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diff --git a/old/54576-0.txt b/old/54576-0.txt deleted file mode 100644 index cbc8276..0000000 --- a/old/54576-0.txt +++ /dev/null @@ -1,10976 +0,0 @@ -The Project Gutenberg EBook of Lightning Conductors, by Richard Anderson - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms of -the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - - - -Title: Lightning Conductors - Their History, Nature, and Mode of Application - -Author: Richard Anderson - -Release Date: April 19, 2017 [EBook #54576] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK LIGHTNING CONDUCTORS *** - - - - -Produced by Chris Curnow, Charlie Howard, and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - - - - -LIGHTNING CONDUCTORS - - - - - LONDON: PRINTED BY - SPOTTISWOODE AND CO., NEW-STREET SQUARE - AND PARLIAMENT STREET - - - - -[Illustration: MONUMENT TO GENERAL BAIRD ON THE SUMMIT OF TOMACHAISTLE -NEAR CRIEFF PERTHSHIRE. STRUCK BY LIGHTNING, MAY 28, 1878] - - - - - LIGHTNING CONDUCTORS - - THEIR - HISTORY, NATURE, AND MODE OF APPLICATION - - - BY - RICHARD ANDERSON, F.C.S. F.G.S. - - MEMBER OF THE SOCIETY OF TELEGRAPH ENGINEERS - ASSOC. INST. C. E. - - - _WITH NUMEROUS ILLUSTRATIONS_ - - - LONDON - E. & F. N. SPON, 46 CHARING CROSS - - NEW YORK - 446 BROOME STREET - 1880 - - - - -_PREFACE._ - - -The want in England of a good practical work on Lightning Conductors, -accessible to both the professional and non-professional reader, has -long been a subject of remark. That there are English works bearing -more or less on Lightning Protection will be seen at once on reference -to the Bibliography contained in the Appendix, pp. 231–248. But it -will be found these books are either obsolete and out of print, or are -written in a purely popular style that conveys little or no ‘usable’ -information whereby may be obtained a trustworthy account of the growth -and application of the LIGHTNING CONDUCTOR. - -It is with a view of meeting this need that the present work has been -written. It contains not only a history of the various methods that -have been used to this end, but also a thoroughly practical exposition -of the systems employed by the best authorities in various countries. - -To Architects, Clergymen, Municipal Officials, and all those in charge -of large and lofty buildings, it would be impossible to over-estimate -the importance of this subject. Year by year an enormous amount of -property is destroyed merely because the simplest precautions have not -been taken to guard churches and other large buildings from the effects -of thunder storms. - -The Author of this work can at all events claim a large practical -acquaintance with its subject. He feels convinced that those concerned -in the preservation of buildings, whether they be houses, churches, or -public offices, need only to learn the simple methods that can be used -to render the action of lightning innocuous, in order to adopt them. - - R. A. - - NEW MALDEN, SURREY: - _October 1879_. - - - - -_CONTENTS._ - - - CHAPTER PAGE - - LIST OF BOOKS REFERRED TO, OR CONSULTED, RELATING TO - LIGHTNING CONDUCTORS xi - - I. ELECTRICITY AND LIGHTNING 1 - - II. DISCOVERY OF THE LIGHTNING CONDUCTOR 17 - - III. EARLY EXPERIMENTS WITH LIGHTNING CONDUCTORS 25 - - IV. GRADUAL SPREAD OF LIGHTNING CONDUCTORS IN EUROPE 34 - - V. METALS AS CONDUCTORS OF ELECTRICITY 49 - - VI. CHARACTER OF LIGHTNING AND OF THUNDERSTORMS 62 - - VII. INQUIRIES INTO LIGHTNING PROTECTION 73 - - VIII. SIR WILLIAM SNOW HARRIS 85 - - IX. THE BEST MATERIAL FOR CONDUCTORS 100 - - X. HÔTEL DE VILLE, BRUSSELS, AND WESTMINSTER PALACE 111 - - XI. WEATHERCOCKS 121 - - XII. LIGHTNING PROTECTION IN FRANCE AND AMERICA 125 - - XIII. LIGHTNING PROTECTION IN ENGLAND 140 - - XIV. ACCIDENTS AND FATALITIES FROM LIGHTNING 169 - - XV. THE EARTH CONNECTION 198 - - XVI. INSPECTION OF LIGHTNING CONDUCTORS 218 - - - APPENDIX 231 - - INDEX 249 - - - - -_LIST OF BOOKS_ - -REFERRED TO, OR CONSULTED, RELATING TO THE HISTORY, NATURE, AND MODE OF -APPLICATION OF - -LIGHTNING CONDUCTORS. - - - ACHARD (Fr. K.) Kurze Anleitung ländliche Gebäude vor - Gewitterchäden sicher zu stellen. 8vo. Berlin, 1798. - - ARAGO (François). Meteorological Essays. Translated by Colonel - Sabine; with an Introduction by Baron von Humboldt. 8vo. - London, 1855. - - BARBERET (J.) Dissertation sur le Rapport qui existe entre les - Phénomènes de Tonnerre et ceux de l’Electricité. 2 vols. 4to. - Bordeaux, 1750. - - BEAUFORT (Dr. Antonin de). Notice sur les Paratonnerres. 8vo. - Châteauroux, 1875. - - BECCARIA (C. B.) Lettere dell’ Elettricismo. 4to. Bologna, 1758. - - BECCARIA (Giambatista). A Treatise upon Artificial Electricity. - Translated from the Italian. 8vo. London, 1776. - - BECQUEREL (Antoine C.) Traité de l’Electricité et du Magnétisme. 7 - vols. 8vo. Paris, 1834–40. - - BERGMAN (T.) Tal on möjeligheten at förexomma askans skadeliga - werkningar. 4to. Stockholm, 1764. - - BIGOT (P.) Anweisung zur Anlegung, Construction und Veranschlagung - der Blitzableiter. 8vo. Glogau, 1834. - - BODDE (M.) Grundzüge zur Theorie der Blitzableiter. 8vo. Münster, - 1804. - - BOECKMANN (N.) Ueber die Blitzableiter. 8vo. Karlsruhe, 1791. - - BREITINGER (D.) Instruction über Blitzableiter. 4to. Zürich, 1830. - - BUCHNER (Dr. Otto). Die Konstruction und Anlegung der - Blitzableiter, mit einem Atlas. 2nd edition, 8vo. Weimar, 1876. - - CALLAUD (A.) Traité des Paratonnerres. 8vo. Paris, 1874. - - CAVALLO (Tiberius). A Complete Treatise on Electricity. 2 vols. - 8vo. London, 1786. - - DALIBARD (M.) Histoire abrégée de l’Electricité. 2 vols. 8vo. - Paris, 1766. - - DAVY (Sir Humphrey). Elements of Chemical Philosophy. 8vo. London, - 1810. - - DEMPP (K. W.) Vollständiger Unterricht in der Technik der - Blitzableitersetzung. 8vo. München, 1842. - - EBERHARD (Dr.) Vorschläge zur bequemeren und zicherern Anlegung der - Pulvermagazine. 8vo. Halle, 1771. - - EISENLOHR (Dr. W.) Anleitung zur Ausführung und Visitation der - Blitzableiter. 8vo. Karlsruhe, 1848. - - EITELWEIN (J. A.) Kurze Anleitung auf welche Art Blitzableiter an - den Gebäuden anzulegen sind. 8vo. Berlin, 1802. - - FAIT (E. M.) Observations concerning Thunder and Electricity. 8vo. - Edinburgh, 1794. - - FERGUSON (James). An Introduction to Electricity. 3rd edition, 8vo. - London, 1778. - - FIGUIER (Louis). Les Merveilles de la Science. 4to. Paris, 1867. - - FONVIELLE (Wilfrid de). Eclairs et Tonnerres. 8vo. Paris, 1869. - - FONVIELLE (Wilfrid de). De l’Utilité des Paratonnerres. 8vo. Paris, - 1874. - - FRANKLIN (Benjamin). Experiments and Observations in Electricity, - made at Philadelphia, in America. 8vo. London, 1751. - - FRANKLIN (Benjamin). Complete Works in Philosophy, Politics, and - Morals. 3 vols. 8vo. London, 1806. - - FRANKLIN (William Temple). Memoirs of the Life and Writings of - Benjamin Franklin. 4to. London, 1818. - - GAY-LUSSAC (F.) et POUILLET (Claude). Introduction sur les - Paratonnerres, adoptée par l’Académie des Sciences. 8vo. Paris, - 1874. - - GRENET (E.) Construction de Paratonnerres. 8vo. Paris, 1873. - - GROSS (J. F.) Grundsätze der Blitzableitungskunst. 8vo. Leipzig, - 1796. - - GUERICKE (Otto von). Experimenta nova Magdeburgica. Folio. - Amsterdam, 1672. - - GÜTLE (J. K.) Neue Erfahrungen über die beste Art Blitzableiter - anzulegen. 8vo. Nürnberg, 1812. - - HARRIS (William Snow) On the Nature of Thunderstorms, and the Means - of Protecting Buildings and Shipping against Lightning. 8vo. - London, 1843. - - HARRIS (Sir William Snow). A Treatise on Frictional Electricity. - Edited by Charles Tomlinson. 8vo. London, 1867. - - HELFENZRIEDER (J.) Verbesserung der Blitzableiter. 8vo. Eichstädt, - 1783. - - HEMMER (J. J.) Kurzer Begriff und Nutzen der Blitzableiter. 8vo. - Mannheim, 1783. - - HEMMER (J. J.) Anleitung Wasserableiter an allen Gattungen vor - Gebäuden auf die sicherste Art anzulegen. 8vo. Frankfurt, 1786. - - HENLEY (William). Experiments concerning the Different Efficacy - of Pointed and Blunt Rocks in securing Buildings against the - Stroke of Lightning. 8vo. London, 1774. - - HOLTZ (Dr. W.) Ueber die Theorie, die Anlage und die Prüfung der - Blitzableiter. 8vo. Greifswald, 1878. - - IMHOF (M. von). Theoretisch-practische Anweisung zur Anlegung - zweckmässiger Blitzableiter. 8vo. München, 1816. - - INGENHOUSZ (Dr. Johan). New Experiments and Observations concerning - Various Subjects. 8vo. London, 1779. - - KLEIN (Hermann J.) Das Gewitter und die dasselbe begleitenden - Erscheinungen. 8vo. Graz, 1871. - - KUHN (Carl). Handbuch der angewandten Elektricitätslehre. Part I. - Ueber Blitzableiter. 8vo. Leipzig, 1866. - - LANDRIANI (M.) Dell’ Utilità di Conduttori elettrici. 4to. Milano, - 1785. - - LAPOSTOLLE (M.) Traité des Parafoudres et des Paragrêles. 8vo. - Amiens, 1820. - - LENZ (Heinrich F. E.) Handbuch der Physik. 2 vols., 8vo. - Petersburg, 1864. - - LICHTENBERG (G. Ch.) Neueste Geschichte der Blitzableiter. 8vo. - Leipzig, 1803. - - LUTZ (F.) Unterricht vom Blitze und Wetterableitern. 8vo. Nürnberg, - 1783. - - MAFFEI (F. S.) Delle Formazione dei Fulmini. 4to. Verona, 1747. - - MAHON (Lord). Principles of Electricity. 4to. Elmsly, 1780. - - MARUM (M. van). Verhandeling over hat Electrizeeren. 8vo. - Groningen, 1776. - - MELSENS (M.) Notes sur les Paratonnerres, in ‘Bulletins de - l’Académie Royale de Belgique.’ 8vo. Bruxelles, 1874–78. - - MELSENS (M.) Des Paratonnerres. 4to. Bruxelles, 1877. - - MEURER (Heinrich). Abhandlung von dem Blitze und den - Verwahrungsmitteln gegen denselben. 4to. Trier, 1791. - - MURRAY (N.) Treatise on Atmospheric Electricity, including - Observations on Lightning Rods. 8vo. London, 1828. - - NEWALL (R. S.) Lightning Conductors: their use as protectors of - buildings, and how to apply them. 8vo. London, 1876. - - NOAD (Henry M.) Lectures on Electricity. 8vo. London, 1849. - - NOAD (Henry M.) A Manual of Electricity. 8vo. London, 1855. - - NOLLET (Abbé J. A.) Leçons de Physique expérimentale. 6 vols. 12mo. - Paris, 1743. - - NOLLET (Abbé J. A.) Recherches sur les Causes particulières des - Phénomènes électriques. 8vo. Paris, 1749. - - OHM (Georg Simon). Bestimmung des Gesetzes nach welchem die Metalle - die Contact-Electricität leiten. 8vo. Nürnberg, 1826. - - PARTON (James). Life and Times of Benjamin Franklin. 2 vols. 8vo. - New York, 1864. - - PHIN (John). Plain Directions for the Construction of Lightning - Rods. 8vo. New York, 1873. - - PLIENINGER (Dr. P.) Ueber die Blitzableiter. 8vo. Stuttgart, 1835. - - PONCELET (Abbé M.) La Nature dans la Formation du Tonnerre. 8vo. - Paris, 1766. - - POUILLET (Claude S. M.) Eléments de Physique expérimentale et de - Météorologie. 7th edition, 2 vols. 8vo. Paris, 1856. - - PRAIBSCH (Christian). Ueber Blitzableiter, deren Nutzbarkeit und - Anlegung. 8vo. Zittau und Leipzig, 1830. - - PREECE (W. H.) On Lightning and Lightning Conductors, in ‘Journal - of the Society of Telegraph Engineers.’ 8vo. London, 1873. - - PRIESTLEY (Dr. Joseph). The History and Present State of - Electricity. 2 vols. 8vo. London, 1775. - - REIMARUS (J. A. H.) Vom Blitze. 8vo. Hamburg, 1778. - - REIMARUS (J. A. H.) Ausführliche Vorschriften zur Blitz-Ableitung - an allerlei Gebäuden. 8vo. Hamburg, 1794. - - ROBERTS (M.) On Lightning Conductors, particularly as applied to - Vessels. 2 vols. 8vo. London, 1837. - - ROWELL (G. A.) An Essay on the Cause of Rain and its Allied - Phenomena. 8vo. Oxford, 1859. - - SAUSSURE (H. B. de). Manifeste, en exposition abrégée, de l’Utilité - des Conducteurs électriques. 8vo. Genève, 1771. - - SIGAUD DE LA FOND (M.) Précis historique et expérimental des - Phénomènes électriques. 2nd edition, 8vo. Paris, 1785. - - SINGER (George John). Elements of Electricity. 8vo. London, 1814. - - SPANG (Henry W.) A Practical Treatise on Lightning Protection. 8vo. - Philadelphia, 1877. - - SPARKS (Jared). The Works of Benjamin Franklin; with Notes and a - Life of the Author. 10 vols. 8vo. Boston, 1840. - - SPRAGUE (John F.) Electricity: its Theory, Sources, and - Applications. 8vo. London, 1875. - - STRICKER (Dr. Wilhelm). Der Blitz und seine Wirkungen. 8vo. Berlin, - 1872. - - STURGEON (William). Lectures on Electricity. 8vo. London, 1842. - - TAVERNIER (A. de). Blitzableiter, genannt Anti-Jupiter. 8vo. - Leipzig, 1833. - - TINAN (Barbier de). Mémoires sur les Conducteurs pour préserver les - Edifices de la Foudre. 8vo. Strasbourg, 1779. - - TOALDO (Giuseppe). Della Maniera di defendere gli Edifizii dal - Fulmine. 8vo. Firenze, 1770. - - TOALDO (Giuseppe). Dei Conduttori per preservare gli Edifizii da - Fulmine. 4to. Venezia, 1778. - - TOMLINSON (Charles). The Thunderstorm. 8vo. London, 1859. - - TYNDALL (John). Notes on Electrical Phenomena. New edition, 8vo. - London, 1876. - - VERATTI (J.) Dissertatione de Electricitati cœlesti. 8vo. Bologna, - 1755. - - WEBER (F. A.) Abhandlung von Gewitter und Gewitterableiter. 8vo. - Zürich, 1792. - - WHARTON (W. L.) The Effect of a Lightning Stroke. 8vo. London, 1841. - - WILSON (Robert). Boiler and Factory Chimneys; with a chapter on - Lightning Conductors. 8vo. London, 1877. - - WINCKLER (Prof. J. H.) Gedanken von den Eigenschaften, Wirkungen - und Ursachen der Elektricität. 8vo. Leipzig, 1744. - - YELIN (J. C. von). Ueber die Blitzableiter aus - Messingdrahtstricken. 8vo. München, 1824. - - - - -LIGHTNING CONDUCTORS: - -THEIR - -HISTORY, NATURE, AND MODE OF APPLICATION. - - - - -CHAPTER I. - -ELECTRICITY AND LIGHTNING. - - -‘First let me talk with this philosopher: What is the cause of -thunder?’ asks Shakspeare in ‘King Lear’ but without giving a reply. -The ‘philosopher’ of Shakspeare’s days had no answer to make; nor -had any others long after. From the dawn of history till within -comparatively modern times, thunder and lightning were mysteries to the -human mind; nor did there exist so much as a surmise that there might -be any connection between them and the equally mysterious agent called -electricity. The latter force indeed revealed itself early to attentive -observers, though in forms very different from those known at the -present time. The Greeks found out that amber, or ‘electron,’ attracted -certain other bodies under friction, and named the force after it; and -the Romans were aware that the shocks discharged by the torpedo fish -were of electrical nature, and they used them for the cure of rheumatic -complaints in the reign of the Emperor Tiberius. Both Greeks and Romans -also observed the sparks emitted, under certain circumstances, from -clothing and from the fur of animals. But this represented the total -sum of knowledge about electricity for ages and ages. - -It was not until the year 1600 that Dr. William Gilbert, physician -to Queen Elizabeth, made a great step forward by showing in his -celebrated work, ‘De magnete, magneticisque corporibus, et de magno -magnete tellure, physiologia nova,’ that the two classes of phenomena, -the magnetic and the electric, are emanations of a single fundamental -force pervading all nature. Dr. Gilbert further discovered that many -other substances besides amber possess the electric power, and that -this power is easily excited when the air is dry and cool, and with -difficulty when it is moist and warm. These discoveries caused great -commotion in the European learned world, yet produced no further result -for another half a century. In 1650, Otto von Guericke, burgomaster -of Magdeburg, the inventor of the air-pump, who had studied with -deep interest Dr. Gilbert’s book, succeeded in constructing a little -electrical machine, composed mainly of a ball of sulphur mounted -on a revolving axis. By the aid of this instrument, very rude in -construction, he produced powerful sparks and flashes of electric -light, and it helped him likewise to discover, first, that bodies -excited by friction communicate their electricity to other bodies -by mere contact, and, secondly, that there resides in electrified -substances the power of repulsion as well as that of attraction. - -Those who followed in the wake of the ingenious burgomaster of -Magdeburg for the next ninety or hundred years, till towards the middle -of the eighteenth century, did very little towards adding to the -already acquired knowledge of electricity. Sir Isaac Newton constructed -an electrical machine of glass, very superior to that of Otto von -Guericke, with which he made some amusing experiments; but, strangely -enough, drew no conclusions from them, treating the mighty force under -his eyes as only a plaything. This was all the more singular as a -contemporary of the great philosopher, Francis Hauksbee, like him a -Fellow of the Royal Society, called attention, in a volume entitled -‘Physico-mechanical Experiments,’ published in 1709, to the great -similarity between the electric flash and lightning, hinting that the -two might possibly be offspring of the same mysterious force. Dr. Wall, -in 1708, said that the light and crackling of rubbed amber seemed in -some degree to represent thunder and lightning. Another member of the -Royal Society, Stephen Gray--the first man in England who made the -study of electricity the devotion of his life, but of whose career very -little is known beyond the fact that he was very poor, and a pensioner -of the Charterhouse--added numberless experiments to those previously -made, and was bold enough to declare, in 1720, six years before Sir -Isaac Newton’s death, that ‘electricity seems to be of the same nature -with thunder and lightning--if we may compare great things with small.’ -For this audacity in ‘comparing things’ he was sharply taken to task by -all the scientific men of the age, and, as deserved, set down as a man -out of his senses. - -Nothing more was done for the next twenty-five years to enlarge the -knowledge of the phenomena of electricity. It stood, in fact, on a -footing not very far advanced from what it had been two thousand -years before. The achievements mainly consisted in a great number -of entertaining experiments performed for the delectation of great -and little children. Various machines had been made for exciting -electricity, but they served only, or at least chiefly, for amusement, -allowing ladies to fire off a cannon by a touch of their delicate hand, -and bringing ladies and gentlemen together to behold the wonderful -spectacle of an infant’s hair being made to stand on end, the little -creature having been placed upon cakes of resin, and fastened to the -ceiling by silken cords. The whole was little more than a repetition, -on a greater scale and with improved means, of the ancient Greek -experiment of rubbing a piece of amber on the sleeve of a philosopher’s -coat. - -The first great step towards a practical insight into the nature and -phenomena of electricity, hitherto a mere plaything, was made in -the year 1745 in the ancient Dutch city and university of Leyden. -Two professors of the high school, John Nicholas Allamand, a member -of the Royal Society of London, and Peter Van Musschenbroek, author -of a treatise entitled ‘Introductio ad philosophiam naturalem,’ had -been trying, like many other scientific men of the time, electrical -experiments, when the thought occurred to them that the real reason -why all the work of the same kind had as yet produced such slight -results was that the electrical force was absolutely unstable. It -slipped, so to speak, through their hands, before they could look at -it; it vanished ‘like a dream, leaving no substance behind.’ One body, -they knew, had the power of electrifying another, but only to let -the mysterious force pass on, like a current of water running down a -cataract. Could they but ‘bottle up’ electricity, what a grand gain -would this be to science! So thought the two professors of Leyden -university; and thought justly. They went on experimenting, with this -end in view, till at last so-called ‘accident,’ the mother of millions -of human inventions and discoveries, threw a brilliant light on the -dark road along which they were groping their way. - -One day Professor Allamand and Van Musschenbroek, together with a pupil -named Cuneus--a sort of Wagner, it would seem, sitting at the feet -of Dr. Faust--were trying the effects of electricity on a small iron -cannon, suspended by silk threads, and connected by a wire with a glass -bottle half full of water, when whey were startled by an extraordinary -incident. Curious, like all students of occult sciences, young Cuneus -took it into his head to see what would happen if he held the prime -conductor of the electrical machine in one hand and the electrified -bottle of water in the other. Something wonderful happened, indeed, -causing profound amazement and terror to the three persons witnessing -it, most of all to the immediate experimenter, who sank down on the -floor, half dead with fright. Master Cuneus had received an electric -shock. It was the first electric shock ever administered by artificial -means to any human being. - -Such was the origin of the long-famous ‘Leyden jar,’ or, as it was -originally called, ‘Leyden phial.’ The whole of the scientific world -of Europe was as much startled by the discovery that electricity -could be imprisoned, like Ariel in an oak-tree, as the two Leyden -professors and their pupil had been, and a perfect fury set in for more -experiments. A professor of the University of Leipzig, in Germany, Dr. -Winckler, started the excitement by submitting his body to frequent -powerful shocks, opening up, besides, a scientific discussion in which -he came forth as the champion of the proposition that the discovery -of the ‘Leyden phial’ was due, not to the professors in the Dutch -university, but to a German ecclesiastic, Ewald George von Kleist, -who made the experiments of Messrs. Allamand and Van Musschenbroek a -year before them. His own sensations in submitting to the force of -electric shocks, Professor Winckler described, doubtless with some -exaggeration, as being convulsed from head to toe, and the prey of -violent agitations, which threw his arms about, and made the blood rush -from his nose. Dr. Winckler did not venture upon many experiments; but -his spouse, undismayed by the arm-shaking and nose-bleeding of her -lord, and having the combined curiosity of a woman and a professor’s -wife, continued upon her own person the electric shocks. However, -she did not take many, nor did science gain by the sacrifice. When a -few graspings of the ‘Leyden phial’ had deprived her of the power to -walk, and, what was worse, to speak, she followed the example of her -bleeding husband, and took ‘cooling medicines.’ All these wonderful -facts were made widely known at the time, and created the most profound -interest. Professor Musschenbroek, of Leyden, added not a little to the -prevailing excitement by writing to his friend René Antoine de Réaumur, -inventor of the thermometer named after him, a long letter, given at -once to the public, in which he dwelt upon the terrible effects of the -mysterious agency which he had helped to call into being, and wound -up by declaring that he had become terrified by his own foster-child, -and that he would not submit to another electric shock ‘for the whole -kingdom of France.’ - -Experiments in electricity now became the prevailing mania. Louis XV. -of France set the fashion among crowned heads of having his soldiers -electrified, to see what benefit he, or they, would derive from it. On -the instigation of Abbé Nollet, considered a man of high scientific -attainments, and who made several important discoveries in electricity, -the King submitted, in his own presence, 180 of the tallest men of his -life-guards, fastened hand to hand by iron wires, to repeated charges -from a connected group of Leyden jars. The big fellows were not visibly -influenced by the electric shocks, experiencing not so much as the -historical nose-bleeding of Professor Winckler of Leipzig, still less -the dumbness of his worthy spouse. On the contrary, the wire-bound -royal guards, conscious of but very slight sensations from the electric -shocks, and feeling somewhat indignant at this, and of being made -scientific tools without at least getting a strong bump on the head, -spoke out strongly, declaring the whole matter to be an imposture. - -Having failed to electrify his soldiers, Louis XV. tried his monks. -It struck his Most Christian Majesty that perhaps the human creatures -who had the honour of fighting for him were endowed by nature with -rather tough hides, and that the case might be different in regard -to the softer beings upon whom devolved the task of praying for him. -Accordingly, the King issued orders that all the monks of the grand -convent of the Carthusians at Paris, over 700 in number, should be -electrified by the same connected group of Leyden jars which had -been tried upon the company of life-guards. The result was entirely -different, and most gratifying to the King. The shock had no sooner -been given when the whole file of monks gave an instantaneous jump, -uttering a howl at the same time. There were some eye-witnesses of -the affair who asserted that the Carthusians jumped and howled even -before the shock had been given, on seeing some one approach the Leyden -jar; but this was officially denied. King Louis XV. was so delighted -with this result of his scientific investigations, that he proposed -to submit all the monks of all the monasteries of France successively -to the process of being electrified, so that it might be accurately -ascertained upon what religious orders and communities it took the -greatest effect. His Majesty likewise was pleased to suggest, that, -after all the monks had been electrified, the nuns might be tried in -their turn. But the proposal was vetoed at Rome. There came definite -orders from the Supreme Pontiff forbidding the contact of any more -persons in the service of the holy Catholic Church with the sinful -electric wire; and the Carthusians of Paris remained the last monks, -as they had been the first, brought to jump and howl at the touch of a -Leyden jar. - -From France and the continent of Europe the mania for electrical -experiments spread into England. But here it was taken up in a -thoroughly practical spirit, worthy of the genius of the nation. -Instead of aiming merely at the production of wonderful phenomena, -made to create astonishment, a number of scientific gentlemen formed -themselves into a body for the express purpose of seeking to ascertain -the nature, effects, and conditions of the mysterious agent which had -obtained the name of electricity. At the head of this body of inquirers -was Dr. William Watson, a member of the Royal Society, indefatigable -in the pursuit of science, and with him worked Martin Folkes, then -president of the Society, Lord Charles Cavendish, Dr. Bevis, and other -distinguished men. They set themselves, first of all, to ascertain in -what manner electricity was communicated through the solid earth, as -well as through fluid bodies; and, secondly, to enter upon experiments -showing the amount of speed at which the force travelled. With the -first object before them, they made some curious trials in the month -of July 1747, which attracted all London. They hung a wire over the -Thames, close to Westminster Bridge, attaching the one end to a Leyden -jar, and giving the other to a man who held it in the left hand, while -he grasped with the right an iron rod, standing in the river. Facing -the latter, on the opposite side of the Thames, not far from the -operators with the ‘jar,’ was stationed another person, also grasping -an iron staff planted in the river. After the charge had been given, -it was found that the electricity, after travelling by the wire over -the river, had come back by the water, the person holding the iron -staff on the starting side not only experiencing a shock himself, but -several individuals touching him. Not content with this experiment, -showing the transmission of electricity, Dr. Watson and his friends -made another, on a larger scale, a week afterwards, on the New River, -at Stoke Newington, London. They spanned, by chains and wires, a -circuit embracing 800 feet by land and 2,000 by water, with the result -of finding that the water transmitted the electric force by itself, if -merely an iron staff was placed in it. But they also discovered at the -same time that moist land would carry the force, equally with water. -To ascertain the latter fact more distinctly, the investigators made -a third experiment at Highbury Barn, Islington, setting up some miles -of wire, separated partly by land and partly by water. The conduit -of the electric force throughout the whole distance was found to be -uninterrupted, which led Dr. Watson to proclaim his conviction that the -agent was far more abundant throughout nature than had been formerly -believed. - -In order to ascertain the speed at which the electric force traversed -space, Dr. Watson and his friends next entered upon a series of -experiments at Shooter’s Hill, near London. They sent an electric -discharge a distance of four miles, observers being stationed at each -end, and a gun fired at the touch of the Leyden jar, when it was shown -conclusively that the movement of the electric force was instantaneous. -This was an important step in advance, in overthrowing all formerly -established conclusions as to the agency being produced by a succession -of waves, like sound, and as such, moving slowly through space. - -The field for electrical experiments was now becoming gradually -more extensive, and a few more practical tests of Mr. Watson and his -coadjutors led the way to the greatest knowledge of the all-pervading -force that had yet been achieved, in the clear apprehension that -lightning was but a manifestation of electricity. The new experiments -were chiefly made with the so-called electrical tube, a glass rod, from -two and a half to three feet in length and about an inch in diameter. -It had been known for some time that the tube, when gently warmed, so -as to be perfectly dry, and rubbed with a silk handkerchief, exhibited -strong symptoms of electricity, to the extent of throwing off luminous -sparks, which obtained the name of ‘electric fire.’ Dr. Watson found, -to his surprise, that this electric fire was not general and always -obtainable, but conditional upon circumstances. Having rubbed a glass -tube while he was insulated by standing upon a cake of wax, he found -that no electricity could be drawn from him by another person who -touched any part of his body, but that the same person could obtain -sparks from the tube by putting his hand near it. Dr. Watson likewise -observed, in the same train of experiments, that if an electrical -machine, together with the person turning the handle, were suspended -by silk, electric fire was not apparent until he touched the floor -with one foot, when the fire appeared upon the conductor. Having made -a great number of trials of a like nature, Dr. Watson made known the -important conclusion derived from them, namely, that glass tubes and -all similar ‘electrifiers’ did not contain within themselves the subtle -agent known as electricity, but formed only its temporary place of -rest, as a sponge would that of water. Dr. Watson was near proclaiming -the fact that electricity resides everywhere throughout the universe; -but for a moment he only touched the fringe of it. The discovery of -this grand truth was left to later investigators. - -One curious result of the experiments made by Dr. Watson and his -friends, and which they themselves probably did not expect, was the -breaking out of a sort of public frenzy for making like trials, but -after the most childish fashion. Everybody who had, or thought he had, -the least tincture of science in him, procured a long glass tube, -and went on rubbing it assiduously with his handkerchief, sitting in -dark rooms and cellars, so as to be better able to watch the first -appearance of the ‘electric fire.’ Ladies and gentlemen alike went on -rubbing, with desperate energy, as if the fate of the world depended on -their exertions. They sold ‘electrical tubes’ in pastry shops; every -draper praised his own handkerchiefs as the best for rubbing; and -lecturers upon electricity went about through the length and breadth -of the land, with glass rods in their hands, delivering wonderful -harangues, and trying to explain to gaping multitudes the mysteries of -nature as regards electricity. The lecturers even crossed the Atlantic -to America, visiting the chief towns, and preaching to large assemblies -in places-- - - Where blind and naked ignorance - Delivers brawling judgments, unabashed - On all things, all day long. - -If it was a ludicrous spectacle to see these wandering lecturers, with -their glass tubes and pocket-handkerchiefs, the movement nevertheless -produced, apparently quite by accident, a striking result. It occurred -through one of the peripatetic preachers of electric revelation -coming face to face with Benjamin Franklin, a printer established -at Philadelphia, when on a visit to his native town of Boston, -Massachusetts, North America. - -There are, in the records of scientific discovery, few figures so -interesting, because so full of marked individualism, as that of -Benjamin Franklin. He was not a man of genius, in the accepted sense -of the word; nor was he even a man of high talents. But he was -nevertheless a decidedly great man, his greatness consisting in the -largest development of that undefined faculty known as common sense. -Benjamin Franklin was the very ideal of a ‘practical’ man, that is, -a man valuing thoughts only as leading to actions, and new ideas -only as the road to visible results. The success of his career in -life was but an illustration of his thoroughly practical character. -Born at Boston in January 1706, the son of a tallow-chandler and -soap-boiler, he was destined by his parents to follow the same trade, -but not relishing the melting pots, he got apprenticed to an elder -brother, a printer at Boston. Harsh treatment drove him away from -this place before the terms of his apprenticeship were over, and with -scarcely a penny in his pocket, and the experience of only seventeen -years in his brain, he made his way to Philadelphia. A year after, -when eighteen years of age, he was induced to sail for England, and -was fortunate enough to find employment as a compositor in a printing -office in London, but so poor as to be compelled to take a lodging -for eighteen-pence a week. However, his self-reliance never deserted -him; he managed to go unscathed through all the perils of poverty and -friendlessness in a great city, and after a few years went back to -Philadelphia, with a small stock of money and a wealth of experience. -He now set up as a master printer, and gradually, though by very slow -degrees and ceaseless toil, devoted to multifarious objects, rose into -prosperity. For upwards of twenty years, from 1728 to 1748, he was the -most energetic and active man of business in Philadelphia. He was not -only a printer, but an author, an editor of newspapers, a compiler of -almanacks, a publisher, a bookseller, a bookbinder, and a stationer. -He made lamp-black and ink; he dealt in rags; he sold soap and geese -feathers; also, as he frequently made known to his fellow-townsmen -in printed notices, he had always in stock ‘very good sack at six -shillings a gallon.’ To dispose of the numerous articles in his store -he invented the art of advertising, unknown before him at Philadelphia. -All the inquiring minds of the ‘Quaker City’ assembled regularly in the -shop of Benjamin Franklin, ‘the new printing office near the market,’ -which came to form the centre of intelligence, and the source from -which all public movements went forth. - -The reward for all this activity was that at the end of twenty years -Benjamin Franklin had accumulated a handsome fortune, his average -income amounting to over two thousand pounds sterling a year: then -considered a very large sum, and of probably three times the purchase -value it would possess at the present day. With increasing wealth, -the active printer, happy in all his family relations, thought -himself justified to seek a little occasional leisure, which he found -chiefly in visits to Boston, his native town. It was on one of these -visits, made in the summer of 1746, that he went with a friend to -a lecture-hall, scarcely knowing what was to be the intellectual -entertainment prepared for him. It proved a discourse, with -illustrative experiments, upon electricity, by a Dr. Spence, duly armed -with a three-feet glass rod and silk pocket-handkerchief. Benjamin -Franklin was not merely interested: he was startled. It was to him, -as he afterwards declared to one of his friends, the opening of a new -world. - -Perhaps the subject which attracted so suddenly the attention of -Benjamin Franklin might have escaped it again, in the pursuit of his -many vocations, but for another accidental circumstance. It so happened -that, immediately after his return to Philadelphia, there came a parcel -of books from England, accompanied by a present in the shape of an -electrical tube. The sender of it was the London agent of the Library -Company of Philadelphia, Mr. Peter Collinson, a member of the Royal -Society, and as such sharing the general interest in the electrical -experiments of Dr. Watson. The tube, which was accompanied with full -directions for its use, was no sooner unpacked, than Franklin seized -it eagerly and began experimenting, at the same time inspiring the -most sanguine of his friends to follow his example. Glass tubes, made -similar to the one sent from London, were soon procured from a local -manufacturer, and then began a general rubbing. ‘I never before,’ -Franklin wrote, early in 1747, ‘was engaged in any study that so -totally engrossed my attention and my time as this has lately done; for -what with making experiments when I can be alone, and repeating them to -my friends and acquaintances, who, from the novelty of the thing, come -continually in crowds to see them, I have, during some months past, -had little leisure for anything else.’ To the greater number of those -friends and acquaintances who came flocking in crowds to the shop of -the Philadelphia printer, the electric tube was, probably, only looked -upon as a new toy; but it was vastly different as regarded himself. His -keen practical eye seemed to discern at once that the manifestations of -the mysterious force on which he was experimenting contained the germ -of something that might be utilised by men, or brought into obedience -to the human will. - -It is not very clear from the published correspondence of Franklin what -his earliest views on the subject were, but there are many indications -that he conceived for a while that the ‘electric fire’ might be -employed in arts and manufactures. In his usual humorous style he spoke -of these utilitarian aims of his in a letter to Mr. Peter Collinson, -written in the early summer of 1747: ‘Chagrined a little that we -have not been able to produce hitherto anything in the way of use to -mankind,’ he wrote, ‘and the hot weather coming on, when electrical -experiments are not so agreeable, it is proposed to put an end to them, -for this season, in a party of pleasure on the banks of the Schuylkill. -Spirits at this party are to be fired by a spark sent from side to -side through the river, without any other conductor than the water: -an experiment which we some time since performed, to the amazement of -many. Then a turkey is to be killed for our dinner by the electrical -shock, and roasted by the electrical jack, before a fire kindled by the -electrified bottle, when the healths of all the famous electricians in -England, Holland, France, and Germany are to be drunk in electrified -bumpers, under the discharge of guns from the electrical battery.’ - -The longer he experimented, the more fascinated grew Benjamin Franklin -with his study of the phenomena of electricity. In order to be able to -devote himself completely to his darling science, he sold his printing -and publishing business in the year 1748, and went to live in a suburb -of Philadelphia, not far from the banks of the Delaware. At the same -time he purchased a complete set of electrical apparatus, the best that -had yet been manufactured, which had been brought over from Europe by -the same Dr. Spence who had given him his first ideas about electricity -at Boston. With these more perfect means he now continued his -investigations, arriving before long at results that formed an epoch in -the history of electricity. - -The results achieved were wholly of a practical kind. With that strong -common sense which formed the most marked feature of his character, -Benjamin Franklin, at a very early period of his experiments, came -to the conclusion that of the actual _nature_ of electricity we know -nothing, and, in all probability, never can know anything, with our -finite senses. But, never losing sight of this starting point, he -treated electricity as astronomers do the movement of the heavenly -bodies. Of the incomprehensible forces that keep countless worlds in -their courses through measureless space, astronomers know no more than -the most ignorant of mankind; still they are able to arrive at very -accurate calculations concerning the directions followed by stars and -planets, and the amount of time consumed in their wanderings through -the inconceivable universe. To such astronomical endeavours Franklin -limited all his researches, and it was precisely because he so limited -them that he achieved greater successes than any other investigator of -the phenomena of electricity. - -Together with many smaller matters, Benjamin Franklin added three great -discoveries to the knowledge of electricity. The first was that the -electric fluid--so called for want of a better word to express the -action of the mysterious force--will run its course more easily and -quickly through sharply pointed metals than in any other way. This had -never before been demonstrated, nor, probably, been ascertained. The -second great discovery of Franklin was that of positive and negative -electricity, or, as he called it for some time, _plus_ and _minus_, -the latter names being really the most descriptive. Of the actual -existence of these two divisions of the great and marvellous agency, -now attracting and now repelling each other, much was known previous -to Franklin, but he was the first to make them clearly understood, -and to bring their effects within reach of calculation. To these two -discoveries Benjamin Franklin added a third, the greatest of all. He -established the identity between the electric force and lightning, -and upon it based one of the noblest inventions of all ages, that of -the lightning conductor. And perhaps there never was any invention -acknowledged more deeply by mankind. The French Academy expressed it -when, on Franklin’s entrance, all the members rose, and the President -exclaimed ‘_Eripuit cœlo fulmen_.’ - -The identity of the electric force and lightning, vaguely surmised -by previous inquirers, and expressed at times in hints, was not only -firmly asserted by Benjamin Franklin, but at a comparatively early part -of his investigations proved by him in experiments. His broad practical -way of looking at facts succeeded in grasping a truth which all the -learned men before him, who had busied themselves with electrical -experiments, had not been able to lay hold of, simply because they lost -themselves in philosophical abstractions. The professors sought the -unattainable, and he confined himself strictly to what he considered -within reach, and it was thus he gained his end. - -The thoroughly matter-of-fact way in which Franklin went to work -is strikingly exhibited in his own description as to how he came -to the conclusion of the oneness of lightning and electricity. In -reply to a friend and correspondent, living in South Carolina, who -had asked him how he came to such an ‘out-of-the-way idea’ as that -of the majestic fire from the cloud-capped firmament being exactly -the same with the puny gleam from a stick of glass, rubbed with the -sleeve of an old coat, Franklin wrote a highly characteristic letter. -‘I cannot answer your question better,’ he told his friend, ‘than -by giving you an extract from the minutes I used to keep of the -experiments I made. By this extract you will see that the thought was -not so much an out-of-the-way one but that it might have occurred to -any electrician. The extract, dated November 7, 1749--a date worth -remembrance in the history of scientific progress--was as follows -in its entirety:—‘Electrical fluid agrees with lightning, in these -particulars: 1. Giving light. 2. The colour of the light. 3. In the -crooked direction of the flame. 4. In the swift motion. 5. In being -conducted by metals. 6. In the crack, or noise, of the explosion. 7. -The subsisting in water, or ice. 8. In the rending of bodies it passes -through. 9. In destroying animals. 10. In melting metals. 11. In firing -inflammable substances. 12. The sulphurous smell. The electric fluid -is attracted by points, and we do not know whether this property is in -lightning. But since they agree in all the particulars wherein we can -already compare them, is it not probable that they agree likewise in -this? _Let the experiment be made._’ - - - - -CHAPTER II. - -DISCOVERY OF THE LIGHTNING CONDUCTOR. - - -With that liberality which distinguishes all truly great minds, -Benjamin Franklin did not keep his great discoveries to himself, -but communicated them to others in the most open-handed manner. -Ever since he had commenced his electrical experiments, he had sent -the detailed results of them to his London correspondent, Mr. Peter -Collinson, for communication to the Royal Society, and he was not -even prevented from continuing the labour of writing long letters by -the knowledge of the fact that scant notice was taken of them by the -Royal Society. The members of this august learned body, with a few -honourable exceptions, seemed unable to hide their contempt for what -they considered the dabblings in science of a mere tradesman, living -in an obscure little town, in a distant colony. Somebody had mentioned -in public that this person, of the name of Franklin, was a dealer in -rags and goose-feathers, dwelling among money-worshipping Quakers in -the City of Brotherly Love: which naturally was productive of great -merriment, but detrimental to scientific respect. Thus, although by the -influence of Mr. Collinson and some of his friends, the letters from -Philadelphia were read before the Royal Society, they met with scarcely -any attention, and the members broadly expressed their disdain of them -by refusing to allow their insertion in their ‘Transactions.’ Three -whole years elapsed in this way, when at length, in the autumn of 1750, -Benjamin Franklin reported to Mr. Collinson his researches on the -identity of electricity and lightning, together with his ideas that all -damage done by the electric fire descending from the clouds upon the -earth might be put a stop to by fixing iron rods, with sharp points, to -the summit of buildings, which would thus be protected. He added that -he himself intended shortly to verify his conclusions by experiments, -but that, in the meanwhile, it would be well if others did the same. -Never before, perhaps, was a grand idea thrown out to all the world -with more munificence of spirit, and with more entire abnegation of the -very thought of self. - -Franklin’s letter made a great impression upon Mr. Collinson. Anxious -to make it public, while persuaded that the Royal Society would give no -better reception to it than to the author’s previous communications, he -hastened to Mr. Edward Cave, proprietor and editor of the ‘Gentleman’s -Magazine,’ and asked him to print it in his publication, the most -widely read at the time. A man of quick sense, Mr. Cave, too, saw at -once the vast importance of Franklin’s paper, describing his discovery, -and readily offered to print it, but recommended that it should be done -in pamphlet form, as likely to make the facts even more extensively -known than could be the case in his own Magazine. This having been -agreed to, there appeared, early in May 1751, a pamphlet with the -name of Benjamin Franklin on the front page, and a preface by Dr. -Fothergill, entitled, ‘New Experiments and Observations in Electricity, -made at Philadelphia, in America.’ It was the most important -contribution to science published since the appearance, five-and-thirty -years before, of Newton’s ‘Principia.’ - -Like Newton’s book, that of Franklin was not immediately successful--at -least not in England. Not appearing under the patronage of the Royal -Society, the supposed fountain-head of all legitimate science, it -was looked coldly upon by the public and the critics, and it was -only after having been greeted with immense applause in France, that -at last something like justice was done to it in England. The great -success of Franklin’s little treatise in France was due, in the first -instance, to rather accidental circumstances, but was none the less -genuine. By a happy chance a copy of the pamphlet printed by Mr. Cave -fell into the hands of the Count de Buffon, the greatest naturalist of -the age, and whose pre-eminent position was established not only in -France, but throughout the whole of Europe. Himself familiar with the -English language, he yet thought that it was necessary to have the book -immediately translated into French, and he employed for the purpose -Professor Dubourg, a literary man of note, well versed in electrical -science. Under such favourable auspices, Franklin’s pamphlet, carefully -translated, was issued at Paris in the summer of 1751, three or four -months after its appearance in London. Its success in France was as -immediate as it was great, and the wave of it spread at once over -Europe, marked by German, Italian, and Latin translations of the ‘New -Experiments.’ For a considerable time nothing was talked of among the -upper classes of France but the discoveries in science of the unknown -Philadelphia printer, and the king, Louis XV., following the fashion of -the day, ordered a course of the electrical experiments, described by -Franklin, to be performed before him at St. Germain, in the presence of -the whole court. - -A rather ludicrous incident, and which gave rise to a great deal of -scientific tournamenting, added to the celebrity of Franklin’s little -book on the continent of Europe. The greatest of French electricians, -Abbé Nollet, a man of acknowledged merit, but inordinately vain, -was mystified in believing that the pamphlet which caused such an -immense stir at court and among the public was not the production -of the obscure man Franklin of Philadelphia, but got up among his -enemies in England and France, to rob him of his reputation. With this -belief fixed in his mind, he sat down at his desk to write a series -of letters intended to demolish the man of Philadelphia, and proving, -entirely to his own satisfaction, first, that Franklin did not exist -at all; secondly, that he had no right to exist; and thirdly, that -all his pretended discoveries were mere dreams. Not long after the -publication of his letters, the wrathful Abbé received undoubted proofs -from America that at Philadelphia there was a man called Franklin, -who himself mildly asserted his right not only to live, but to make -experiments in electricity. Poor Abbé Nollet felt his humiliation all -the more keenly as holding the post of preceptor in Natural Philosophy -to the royal family of France, and he had to suffer from a ‘burst of -inextinguishable laughter’ at one of his appearances at court. - -If Count de Buffon did great service to electrical science by getting -Franklin’s pamphlet translated into French, he did still more by -instigating a series of experiments tending to verify the great theory -put forward in the pamphlet, that lightning could be drawn from the -clouds by means of pointed iron rods. By his prompting, several -gentlemen interested in scientific pursuits engaged upon trials to this -effect, among them two persons of note, M. Dalibard and M. de Lor. -The first-named had the good fortune to be successful, and thereby to -hand his name down to posterity. A wealthy man of science, M. Dalibard -was in the habit of living, during a part of the year, in a handsome -country house situated at Marly-la-Ville, about eighteen miles from -Paris, on the road to Pontoise. Marly-la-Ville stands on a high plain, -some four hundred feet above the sea-level, and the residence of M. -Dalibard being situated on the most elevated part of the ground, it -formed an excellent place for experiments, and was chosen as such by -Count de Buffon. The garden near the house was selected as the best -ground for the experiments. A wooden scaffolding was built up to hold -in its midst an iron rod, eighty feet long, and slightly over an inch -in diameter. On the top of the rod was fastened a piece of polished -steel, sharply pointed, and bronzed to prevent rust. The iron rod -entered, five feet from the ground, into another thinner one, running -horizontally towards an electrical apparatus, fastened to a table in -a kind of sentry-box, erected on purpose for observations. It was -M. Dalibard’s intention to make the experiments himself; but almost -immediately after the structure in his garden had been completed, he -was called by business to Paris, and left the whole in charge of one -of his servants, an old soldier, formerly in the French dragoons, -Coiffier by name. With true military spirit, Coiffier thought that -he ought to spend the greater part of his time in the sentry-box in -his master’s garden, and there he sat in the afternoon of Wednesday, -May 10, 1752, when a violent thunderstorm drifted over the plain -of Marly. Sufficiently instructed by his master what to do under -the circumstances, he touched the electrical apparatus with a key, -silk-bound at the handle, and to his extreme surprise, sees a flame -bursting forth. He touches another time, and there is a second flame -bursting forth, stronger than before. Then the old dragoon rushes from -his sentry-box--most famous private dragoon that ever lived, born to -the high honour of being the first man that ever drew lightning from -heaven. - -It was not fear that drove the worthy servant of M. Dalibard from his -post, but a far better motive. He judged, with the prudence of an old -soldier, that the astounding things he had seen required witnesses, -in order that his master might not think him an inventor of fairy -tales. Accordingly, he hurried to the house of the prior of Marly, -M. Raulet, who lived close by, and asked him to behold the marvel of -marvels. The prior hesitated not for a moment to go, and, entering the -sentry-box, he also drew sparks from the electrical machine. Others of -the inhabitants of Marly-la-Ville, seeing the prior run, followed in -his wake, notwithstanding the rain was pouring down in streams, and -terror was struck among all of them in witnessing the dreaded lightning -creep down, serpent-like, but bereft of all its terrors, into the -sentry-box, in the centre of which stood the now exulting old dragoon. -As soon as the storm was over, the prior insisted upon Coiffier at -once saddling a horse, and riding full speed to Paris, to acquaint his -master with the great news that lightning had been drawn from the -skies by his apparatus at the blessed village of Marly-la-Ville. The -obedient dragoon did as advised, and three days after, on May 13, 1752, -M. Dalibard startled all the members of the Académie des Sciences of -Paris, convoked together in haste, by reading to them a full report of -what had taken place in the first great experiment for ascertaining the -truth of the suggestions of Benjamin Franklin. - -All Europe soon rang with the report of the marvellous discovery -verified at Marly-la-Ville. But before the news of the experiment -made at the village near Paris had reached America, Benjamin Franklin -had made another, which, if not more conclusive, was at least more -original. Ever since he had arrived at his great conclusion regarding -the sameness of electricity and lightning, and the possibility of -conducting the latter to the ground harmlessly, by means of pointed -rods, the discerning citizen of Philadelphia had tried hard to find -some means for putting his ideas to a practical test, but met with -apparently insurmountable difficulties. His first plan was to set -up simply a tall iron rod near his house; but he abandoned this on -ascertaining, by measurement, that nearly all stormclouds passed over -Philadelphia, which was situated in a plain, at a height of several -hundred feet. In his then state of knowledge, he fancied that it -was impossible for him to reach the clouds in this manner. He next -resolved to await the building of an intended steeple for the principal -ecclesiastical edifice, and highest building of Philadelphia, Christ -Church. At that time not a steeple pierced the sky in all the extent -of the ‘Quaker city;’ nor was there a single one in the whole State -of Pennsylvania. But though Franklin made immense efforts to get the -steeple erected, starting a lottery for the purpose, and subscribing -largely to the funds, the work made little or no progress, many of the -principal inhabitants of the city being, from their religious opinions, -averse to the project. At last, getting impatient, Franklin’s ingenuity -hit upon the simplest of all means for verifying his great discovery. - -One day he saw a boy flying a kite, and the thought instantly -occurred to him that here was the straight road from the earth to the -thunderclouds. Accordingly, he at once set to make a kite for his -intended experiments; but fearing he would incur the ridicule of his -sober fellow-citizens in engaging in what might seem to them a childish -undertaking, he kept the whole matter a profound secret. The kite he -made was not distinguished from those used by boys except of being made -of silk instead of paper so as to be able to stand the wet. Franklin -took an ordinary silk pocket-handkerchief, and fastened it over a cross -made of two light strips of cedar, by simply tying the four corners of -the handkerchief to the ends of the sticks. He next fastened a thin -iron wire, a foot long, to the top of the kite, and having provided it -with a loop and tail, attaching to the former a roll of twine, all was -ready for the experiment. Watching the skies diligently, he saw a dark -thundercloud coming up over Philadelphia late in the evening of July 4, -1752, and at once sallied forth from his house, situated at the corner -of Race and Eight streets, into a neighbouring field. There was nobody -with him but his eldest son, a lad of about twenty; and, in order to -get protection against the heavy downpour, as well as to hide from the -gaze of passers-by, the two sought shelter under an old cow-shed. Very -likely, had they been seen here at the time, the philosopher and son -might have been taken for two escaped lunatics, seeking so propitious -an occasion as a thunderstorm to fly their darling kite. Perhaps -Franklin too felt a little foolish, for he was about relinquishing his -experiment after several flashes of lightning which had not in the -least disturbed his kite, when a cloud darker than the previous one -came rolling up. All on a sudden, Franklin felt a smart shock, and saw -a spark flashing before his eyes. He had fastened the twine holding -his kite to a silk ribbon which he held in his hand, joining twine -and silk by a large key, attached to a Leyden jar. The latter at once -became heavily charged, and as shock followed upon shock, and flash -upon flash, there vanished all doubt from Franklin’s mind as to the -absolute truth of the grand discovery he had made. It may be imagined -with what inward satisfaction the great citizen of Philadelphia drew -in his kite, and crept out from under the cow-shed, when the storm was -over, and went home exultingly, the happiest of philosophers. - -The experiment of Benjamin Franklin in drawing, as he thought, the -electricity of stormclouds to the ground by his kite, and thereby -demonstrating the necessity for the establishment of lightning -conductors, for the protection of persons and buildings, was accepted -as thoroughly satisfactory by the whole scientific world of Europe -at that time. Franklin was wrong, however, in supposing that the -lightning had really passed along his kite-string from the clouds to -the earth, for, had this been the case, he would undoubtedly have -been killed. What he witnessed was merely the inductive action of -the thundercloud on the kite and string. There had been some doubts -in respect to the experiment made, at the suggestion of Franklin’s -pamphlet, at Marly-la-Ville, since all the witnesses were inexperienced -persons, entirely unacquainted with the phenomena of electricity; but -there could be none whatever as regarded that tried by the originator -himself, and pronounced satisfactory by him. The fame of the wonderful -discovery spread with extraordinary swiftness through the civilized -world. Praises and congratulations flowed in upon the hitherto obscure -citizen of Philadelphia from all sides. The king of France sent him -a letter, full of compliments; the Royal Society of London voted him -their gold medal, modestly claiming a share in his work; and nearly -all the scientific bodies of France, Germany, and Italy elected him an -honorary member. But the praise of which Franklin had most reason to -be proud came from the great philosopher Immanuel Kant. The sage of -Königsberg grandly called him the modern Prometheus, bringing fire from -heaven. - - - - -CHAPTER III. - -EARLY EXPERIMENTS WITH LIGHTNING CONDUCTORS. - - -The first actual lightning conductor ever constructed was set up by -Benjamin Franklin himself, at his house in Philadelphia. Its main -object was to protect the house against the effects of thunderstorms; -still experiments were so dear to the heart of the great discoverer, -that he could not help making trials even with things devoted to other -uses. It was in the summer of 1752 that Franklin erected over his house -a lightning conductor, made entirely of iron, but with a sharp steel -point on the top, the latter projecting seven or eight feet above the -roof, while the end was above five feet in the ground. Curious to know -whenever an electrical stream was passing through the conductor, he -attached to it an ingenious contrivance, by means of which through -an electric spark two bells were set in movement as soon as this -took place, the greater or lesser noise from them corresponding with -the strength of the electrical current. With the aid of this device -Franklin was enabled to observe some curious phenomena, which at first -puzzled him not a little. ‘I found the bells rang sometimes,’ he -informed a friend, ‘when there was no lightning or thunder, but only a -dark cloud over the rod; that sometimes, after a flash of lightning, -they would suddenly stop, and at other times, when they had not rung -before, they would, after a flash, suddenly begin to ring; that the -electricity was sometimes very faint, so that when a small spark was -obtained, another could not be got for some time after. At other -times, the sparks would follow extremely quickly; and once I had a -continual stream from bell to bell, the size of a crow-quill. Even -during the same gust there were considerable variations.’ By continued -watching, Franklin came to make the discovery that the fluctuations -in the electrical current were owing to changes and interchanges, -in atmosphere and earth, of positive and negative electricity. He -held at first that thunder-clouds are usually in a negative state of -electricity, but afterwards discovered that they varied from negative -to positive during the same storm. - -Notwithstanding the unbounded praises bestowed upon Benjamin Franklin -for the great discovery of the lightning conductor, the actual -adaptation of it spread with extreme slowness. It was in the country -of its origin that it was brought into public use, all the countries -of Europe lagging far behind. But even in the Northern States of -America, though inhabited by a highly intelligent race, there were -great difficulties to overcome. The ministers of religion at first -seemed to think that the iron rods were not altogether free from the -suspicion of infidelity. Franklin himself had the reputation of being -a free-thinker, and indeed never hid from others the fact of his being -accustomed to examine all matters by the light of his own reason, and -to believe nothing that he could not understand. Perhaps on the same -ground many of the New England ministers did not believe in lightning -conductors. They could not understand them. A heavy shock of earthquake -was felt throughout Massachusetts in the summer of 1755, whereupon a -Boston clergyman instantly came forward, denouncing in eloquent strains -the erection of a number of lightning conductors which had taken place. -The high iron rods, he gravely maintained, had been the cause of the -earthquake, by drawing vast masses of electricity from the atmosphere -into the ground. A distinguished friend of Franklin, Professor -Winthrop, of Harvard College, thought it necessary to come forward and -defend lightning conductors against the accusation of accumulating -electricity, but without convincing the plaintiff. A different charge, -still more serious in the eyes of pious people, had been made against -lightning conductors some years before. Another Boston clergyman, -coming forward in 1770, opposed the use of Franklin’s iron rods on the -ground that, as the lightning was one of the acknowledged means of -punishing the sins of mankind, and of warning them from the commission -of acts of wickedness, it was impious ‘to prevent the execution of the -wrath of heaven.’ To this gentleman also Professor Winthrop deemed -it requisite to reply. Franklin himself remained silent, wrapping -himself in the mantle of the sage. But he allowed his friend Ebenezer -Kinnersley, of Philadelphia, who went travelling, by his wish and -partly at his cost, through the principal towns and villages of the New -England States, to explain to the people the uses and advantages of -lightning conductors, to preface all his lectures by the announcement -that the erection of iron rods to protect houses from the effects -of thunderstorms was not an act ‘chargeable with presumption, nor -inconsistent with any of the principles either of natural or revealed -religion.’ - -In the gradual spread of lightning conductors through the British -colonies of North America, Franklin himself took the leading part. He -employed all his leisure time, engrossed though it was more and more -by political affairs, in which he was destined to take a world-famous -part, in going from one part of the country to another, advocating the -use of conductors, advising as to the best mode of their construction, -and, whenever he could, examining into the effects of strokes of -lightning upon buildings. How minute he was in these inspections, and -how practical in the conclusions he almost invariably drew from them, -Franklin gives proof in one of his letters addressed to his friend -Collinson in London. He tells him that he inspected the church of -Newbury, in Massachusetts, which had been struck by lightning, and -traced, foot by foot and inch by inch, the road which the electric -current had taken, creating great havoc and destruction. ‘The steeple,’ -he says, ‘was a square tower of wood, reaching seventy feet up from -the ground to the place where the bell hung, over which rose a taper -spire, of wood likewise, reaching seventy feet higher, to the vane -of the weathercock. Near the bell was fixed an iron hammer to strike -the hours; and from the tail of the hammer a wire went down through a -small gimlet-hole in the floor the bell stood upon; then horizontally -under and near the plastered ceiling of that second floor, till it came -to a wall; and then down by the side of this wall to a clock which -stood about twenty feet below the bell. The wire was not bigger than -a common knitting-needle.’ It surprised Franklin that ‘the lightning -passed between the hammer and the clock in this wire, without hurting -either of the floors, or having any effect upon them, except making -the gimlet-holes, through which the wire passed, a little bigger, and -without hurting the wall or any part of the building.’ The inference he -drew from this was, that even a comparatively thin mass of metal would -give passage to a powerful electric stream. ‘The quantity of lightning -that passed through the steeple,’ he informed his correspondent, ‘must -have been very great, as shown by its effects on the lofty spire above -the bell, and on the square tower below the end of the clock pendulum; -and yet, great as this quantity was, it was conducted by a small wire -and a clock pendulum, without the least damage to the building as far -as they extended.’ - -Besides travelling and employing lecturers, to make the advantages of -lightning conductors known, Franklin found means of doing so in an -annual publication he had started in the year 1732, known as ‘Poor -Richard.’ This almanac, humorous in form but very serious in substance, -which had acquired an enormous circulation, proved in the end the most -powerful instrument for spreading information on the great subject -dear, above all others, to Franklin’s heart, and leading his countrymen -to adopt, before all other nations, the wonderful metal rod, protective -against ‘the wrath of heaven.’ In several of the editions of the -almanac, notably the ‘Poor Richard’ for the year 1758, Franklin drew -attention to his lightning conductors in simple advertisements, drawn -up in a spirit of absolutely touching modesty and self-abnegation. -Not seeking the slightest reward for himself, nor even mentioning his -name, he only sought to benefit others by instructing them how to get -protection against the dangers of lightning. ‘It has pleased God,’ -ran the advertisement in the almanac, ‘in His goodness to mankind, at -length to discover to them the means of securing their habitations and -other buildings from mischief by thunder and lightning. The method is -this:--Provide a small iron rod, which may be made of the rod-iron used -by nailers, but of such a length that, one end being three or four -feet in the moist ground, the other may be six or eight feet above the -highest part of the building. To the upper end of the rod fasten about -a foot of brass wire, the size of a common knitting-needle, sharpened -to a fine point; the rod may be secured on the house by a few small -staples. If the house or barn be long, there may be a rod and point at -each end, and a middling wire along the ridge from one to the other. -A house thus furnished will not be damaged by lightning, it being -attracted by the points and passing through the metal into the ground -without hurting anything. Vessels also, having a sharp-pointed rod -fixed on the top of their masts, with a wire from the foot of the rod -reaching down round one of the shrouds to the water, will not be hurt -by lightning.’ Franklin had occasion subsequently greatly to modify the -advice here given. He early discovered his error of lightning being -‘attracted by the points;’ and also found that his recommendation to -people to construct their own lightning conductors only led to grievous -calamities. There came reports from all sides of houses having been -severely damaged by lightning notwithstanding having conductors, and -close investigation soon showed that in every instance the apparatus -was defective, having been erected by unskilful hands, either the -owners themselves, or a set of wandering impostors, who soon made -themselves notorious as ‘lightning-rod men.’ - -Having improved in various ways the lightning conductor set up -experimentally over his own house, Franklin erected a second one, of -larger dimensions, to protect the residence of one of his friends, Mr. -West, a wealthy merchant of Philadelphia. The apparatus, constructed -entirely under the supervision of Franklin, consisted of an iron rod -half an inch in diameter throughout its length, and ending at the -bottom in a thick iron stake, driven four or five feet into the ground. -The top of the conductor, rising nine feet above the central stack of -chimneys, was formed by a brass wire ten inches in length, tapering off -in a sharp point. Franklin considered the brass wire, which was screwed -and soldered inside the iron rod, a great improvement upon simple iron, -having discovered brass, as well as copper, to be better conductors of -electricity. The result justified his expectations. Not many months -after the lightning conductor had been erected over the mansion of Mr. -West, a thunderstorm more severe than had been experienced for many -years broke over Philadelphia. Vivid flashes of lightning followed each -other incessantly, one of them striking, visible to all beholders, the -house of Mr. West, touching the point of the conductor on the roof, -and appearing again on its base in a thin sheet of flame. Naturally, -Franklin was delighted at this first notable result of his grand -discovery, and lost no time in examining the traces of the lightning -over his conductor. He found that the sharp metal point at the upper -end had been melted, and the small brass wire reduced from ten to seven -and a half inches, with its top very blunt. The thinnest part of the -wire, he saw at once, had disappeared in smoke, while the portion below -it, a little thicker, had simply been liquefied, sinking down while in -a fluid state, and forming a rough irregular cap, lower on one side -than on the other. This was a highly interesting test, showing that -the wire on the summit of the conductor must not be made too thin, so -as to be liable to be burnt. But still more interesting to Franklin -was the investigation of the report, confirmed on all sides, that a -sheet of flame had been seen at the base of the conductor, where it -was connected with the earth. He at once suspected that the earth at -the point, and down to the end of the metal rod, had been very dry, -and such indeed was the case. Hence he arrived at the conclusion that -all conductors should go deep enough into the earth to find sufficient -moisture quickly to dissipate the electric fluid. All subsequent -experience, down to the present day, has proved that the inference of -the practical philosopher of Philadelphia was as sound in this respect -as in the rest of his ever clear and lucid judgments. - -Like most other inventions and discoveries, that of the lightning -conductor was destined not to be without its early martyrs. Among the -many searchers in the science of electricity on the continent of Europe -who had eagerly seized the ideas of Benjamin Franklin, and entered -enthusiastically upon the experiments recommended by him, was Professor -George Wilhelm Richmann, of St. Petersburg. He had conceived some -theories of his own regarding electrical discharges, and constructed -for experimental purposes an apparatus which he called the ‘gnomon,’ -one of the uses of which was to measure the comparative strength of -electrical currents. The instrument consisted of a tube of metal, -terminating in a small glass vessel, into which, for some unknown -reason, he put a quantity of brass filings. Attached to the tube of -metal, at its top, was a chain, so arranged as to be easily attached -or detached from it, and this was fastened to an iron rod going to the -roof, in the form of a lightning conductor, as prescribed by Franklin. -It seems to have been the notion of the professor that he might lead -the electrical current from the clouds down into his ‘gnomon’ bottle, -there to measure its strength; though it is difficult to conceive -how a man acquainted with the manifestations of the mystic force -with which he was experimenting, and knowing its powerful effects, -should not have perceived the extreme danger of thus leading it into a -nonconducting element. However, the enthusiastic man, evidently blind -to all consequences, set out on his course of experiments. A violent -thunderstorm coming over St. Petersburg on August 6, 1753, Professor -Richmann hurried to his ‘gnomon,’ attached the chain to the phial, and -then stood to watch the effect, with not more than a foot and a half -distance between his head and the glass tube. Near him, but further -behind, stood a friend, M. Solokow, who was going to make a drawing -of the electrical apparatus. All on a sudden, there came a terrible -flash of lightning, described as ‘a ball of fire’ by M. Solokow, down -from the skies, falling upon the ‘gnomon’ and springing from thence -upon Professor Richmann, laid the latter dead on the floor, and his -companion senseless. - -When the body of the unfortunate professor came to be examined, it was -found that the electric current had passed right through him, entering -at the forehead, and coming out at the sole of the left foot, both -places being distinctly marked by red spots and small perforations, -like those of a needle. There were no other marks of injury visible, -either inwardly or outwardly, except a number of red and blue spots -over the back and shoulders, which grew larger the day after, and -seemed to bring with them symptoms of rapid decay. Some of the medical -men attending the ‘post mortem’ examination were most desirous to -enter into further observations, so as to ascertain, if possible, the -actual cause which produced death by a stroke of lightning, but they -had no opportunity. When they returned to the professor’s house, the -second day after his death, the body was already so far decomposed as -to be unrecognisable, and it was with difficulty that the remains of -the first martyr of applied electricity could be got into a coffin and -carried to their last resting-place. - -The appalling death of Professor Richmann produced an enormous -commotion, far beyond what might be expected from a similar event, -throughout the learned world of Europe. In France especially the -occurrence created the deepest impression, mingled with admiration of -what was called the ‘glorious death’ of the St. Petersburg professor, -and more than one student of electrical science boldly declared -his determination to become a martyr in the same noble cause. But -reflection, probably, brought better counsel, for, as it happened, -there were no more contributions, for the time being, to the roll of -martyrs. - -[Illustration] - - - - -CHAPTER IV. - -GRADUAL SPREAD OF LIGHTNING CONDUCTORS IN EUROPE. - - -In singular contrast with the burst of applause with which the whole -scientific world of Europe received the great discovery of Benjamin -Franklin, was the extreme slowness of the actual introduction -into Europe of lightning conductors. The opposition they met -with in Franklin’s own country was trifling to that which they -encountered in the principal states of Europe, more particularly -in England and France. It was natural, perhaps, that the lower -classes--ultra-conservative, through the mere effect of ignorance, in -every country in the world--should see danger in the setting-up of -iron rods which, as they were told, drew lightning from the skies; -and it was, perhaps, equally natural that religious fanatics should -regard them with extreme suspicion, as removing one of their imagined -instruments of heaven for punishing sinful mortals. Both these classes, -the untaught multitude and the bigoted zealots, opposed in Europe, -as they did in America, the establishment of lightning conductors; -but to the strength of these parties was unexpectedly added a third -in a not numerous but powerful section of learned literary men. They -were chiefly French, but had many adherents in England, as well as in -Germany, the _savants_ of both countries looking then upon France as -the seat of all science, and indeed human knowledge. - -The opposition raised against lightning conductors in France was -entirely personal, its origin being due to the wounded vanity of a -very estimable but likewise a very weak man, the already mentioned -Abbé Nollet. Born in 1700, the Abbé had very early in life gained -renown for his scientific researches, and after a while devoted much -of his time to electrical experiments, in conjunction with two other -celebrated men, Dufay and De Réaumur. When the report of Franklin’s -discoveries arrived in Europe, the Abbé Nollet was generally looked -upon as the greatest of living ‘electricians,’ and the general homage -paid to him having roused his self-esteem to an inordinate degree, he -got fiercely irritated that another man, a previously quite unknown -person, in a distant land, should have dared to snatch from him his -scientific laurels. Accordingly, he used all his influence among the -public, in the scientific world, and at the French court, where he held -a high position as tutor of the King’s children, not only to depreciate -Franklin’s lightning conductors, but to set them down as something like -an imposture. In various treatises and articles published in learned -papers, Abbé Nollet sought to prove that the person called Benjamin -Franklin--in whose very existence he formerly refused to believe, but -which he now grudgingly acknowledged--was an individual unacquainted -even with the first principles of the science of electricity, and that -his proposal for protecting houses against lightning was so absurd -as not to be worth engaging the attention of any thinking man. More -than this, he argued that the proposed lightning conductors were not -only inefficacious, but positively dangerous. By thus joining in the -vulgar cry of lightning being, so to speak, sucked from the clouds -by Franklin’s conductors, the learned Abbé had the satisfaction of -retarding their introduction in his own, as well as other European -countries, for a number of years. - -In France itself the thus awakened resistance to the setting-up of -lightning conductors was strikingly shown by an incident which occurred -at the town of St. Omer, not far from Calais. A manufacturer settled -here, who had been in America, and there learnt to appreciate the -usefulness of Franklin’s lightning conductors, had one made for his -own house, and quietly fixed it to wall and roof. But the populace no -sooner heard of it when there arose a public disturbance, and the iron -rod was torn down by force. So far from repressing the rioters, the -municipality of St. Omer, acting under priestly influence, forbade the -manufacturer to erect another lightning conductor, on the ground that -it was ‘against law and religion.’ Thereupon the bold manufacturer, a -man of English descent, to try his right, appealed to the tribunals, -and the judges at last, after protracted pleadings, not being able to -discover any statutes against the fastening of metal rods to buildings, -declared that the thing might be done, but with precautions. The lawyer -who pleaded the case of the lightning conductors before the French -tribunals at this momentous period was a very young man, quite unknown -to fame at the time, but destined for a superabundance of it. His name -was Robespierre. - -Perhaps the violent opposition which the erection of lightning -conductors--or ‘Franklin rods,’ as they were often called--met almost -everywhere, would have proved more effective than it ultimately turned -out, had not the great discoverer himself showed admirable temper in -meeting his enemies, thus pouring oil upon the stormy waters. His -calmness and confidence is admirably shown in a letter, dated July 2, -1768, addressed to Professor John Winthrop, of Cambridge, in answer to -one in which astonishment was expressed at the ‘force of prejudice, -even in an age of so much knowledge and free inquiry,’ of not placing -lightning conductors upon all elevated buildings. Franklin--or he must -now be called Dr. Franklin, having received the degrees of LL. D. -and D. C. L. from the universities of St. Andrew’s, Edinburgh, and -Oxford--was residing in England at the time, as agent of the people of -Pennsylvania. He was thoroughly acquainted with the state of public -feeling, yet so far from being angry, smiled down upon it like a -true philosopher. ‘It is perhaps not so extraordinary,’ he wrote to -his friend, ‘that unlearned men, such as commonly compose our church -vestries, should not yet be acquainted with, and sensible of, the -benefits of metal conductors in averting the stroke of lightning, and -preserving our houses from its violent effects, or that they should -still be prejudiced against the use of such conductors, when we see -how long even philosophers, men of science and of great ingenuity, can -hold out against the evidence of new knowledge that does not square -with their preconceptions; and how long men can retain a practice that -is conformable to their prejudices, and expect a benefit from such -practice, though constant experience shows its inutility. A late piece -of the Abbé Nollet, printed last year in the Memoirs of the French -Academy of Sciences, affords strong instances of this; for though -the very relations he gives of the effects of lightning in several -churches and other buildings show clearly that it was conducted from -one part to another by wires, gildings, and other pieces of metal -that were _within_, or connected with the building, yet in the same -paper he objects to the providing of metallic conductors _without_ the -building, as useless or dangerous. He cautions people not to ring the -church bells during a thunderstorm, lest the lightning, in its way to -the earth, should be conducted down to them by the bell ropes, which -are but bad conductors; and yet he is against fixing metal rods on the -outside of the steeple, which are known to be much better conductors, -and through which lightning would certainly choose to pass, rather than -through dry hemp. And though, for a thousand years past, church bells -have been solemnly consecrated by the Romish Church, in expectation -that the sound of such blessed bells would drive away thunderstorms, -and secure buildings from the stroke of lightning; and, during so long -a period, it has not been found by experience, that places within -the reach of such blessed sound are safer than others where it is -never heard, but that, on the contrary, the lightning seems to strike -steeples by choice, and at the very time the bells are ringing, yet -still they continue to bless the new bells, and jangle the old ones -whenever it thunders.’ - -‘One would think,’ continues Dr. Franklin, with exquisite humour, -‘that it was now time to try some other trick. Ours is recommended, -whatever the able French philosopher may say to the contrary, by more -than twelve years’ experience, during which, among the great number of -houses furnished with iron rods in North America, not one so guarded -has been materially hurt by lightning, and many have been evidently -preserved by their means; while a number of houses, churches, barns, -ships, &c., in different places, unprovided with rods, have been struck -and greatly damaged, demolished, or burnt. Probably, the vestries of -English churches are not generally well acquainted with these facts; -otherwise, since as good Protestants they have no faith in the blessing -of bells, they would be less excusable in not providing this other -security for their respective churches, and for the good people that -may happen to be assembled in them during a tempest, especially as -these buildings, from their greater height, are more exposed to the -stroke of lightning than our common dwellings.’ - -While Franklin thus wrote of ‘the great number of houses furnished with -iron rods in North America,’ there was not a single public building -so protected in England. Several private persons had adopted them for -their houses, following the example of Dr. William Watson--subsequently -Sir William--vice-president of the Royal Society, who had been the -first to set up a lightning conductor in England, erecting one over -his cottage at Payneshill, near London, in 1762. But notwithstanding -the evident utility of the ‘Franklin rods,’ they were refused where -they were most wanted--for larger buildings, and particularly for -churches. The ‘unlearned men, such as commonly compose our church -vestries,’ openly declared against them, and among the clergy there -was a steady, if often silent, antagonism to their introduction. The -first movement towards its being upset was given by an occurrence which -caused much commotion, and gave rise to a vast amount of discussion. -On Sunday, June 18, 1764, a few minutes before three in the afternoon, -the splendid steeple of St. Bride’s Church, in the city of London, one -of the architectural monuments of Sir Christopher Wren, was struck by -lightning, the flash being intensely vivid, blinding several people. -The damage done was so serious that about ninety feet of the steeple -had to be taken down entirely, while great and expensive repairs -were required for the rest. Dr. Watson, as the first introducer, so -one of the chief promoters of Franklin’s invention in England, took -this opportunity of publishing in the ‘Philosophical Transactions’ -a detailed account of the effects of lightning upon St. Bride’s -steeple, explaining the potency of conductors in the very action of the -electric force. He showed how the lightning first struck the metallic -weathercock at the top of the steeple, and ran down, without injuring -anything, the large iron bars by which it was supported. At the bottom -of the bars, the electric force shattered a number of huge stones into -fragments, to make its way to some other pieces of iron, inserted into -the walls to give them strength. So it went on till there were no more -metals, when havoc and destruction became the greatest. Thus, as Dr. -Watson conclusively proved, the beautiful steeple of St. Bride was -wilfully made over to ruin for want of a few hundred yards of iron, or -other metal, which would lead the electric force harmlessly from the -weathercock on the summit into the earth. He finished by telling in -the plainest terms, to all on whom devolved the duty of taking care of -churches, that it was neglectful, even to criminality, not to protect -them by conductors against the always imminent danger of being struck -by lightning. - -The lay-sermon of Dr. Watson, deeply impressive by the power of the -indisputable facts on which it was based, had a considerable effect -in rousing public opinion, finding its way even into the dull ears of -‘such as commonly compose church vestries.’ Among the most important -results was a step taken, after long and solemn deliberations, -extending over several years, by the Dean and Chapter of St. Paul’s. -They made an application to the Royal Society, asking for advice as -to the best means of protecting the great cathedral, Sir Christopher -Wren’s noblest creation, against the perils of lightning. The -application was made on March 22, 1769, as recorded under that date in -the ‘Gentleman’s Magazine.’ ‘A letter from the Dean and Chapter of St. -Paul’s,’ it was stated, ‘was read at the Royal Society, requesting the -direction of that learned body for the sudden effects of lightning. -It was referred to a committee consisting of Dr. Franklyn (_sic_), -Dr. Watson, Mr. Canton, Mr. Edward Delaval, and Mr. Wilson, who, -after having examined the building, are to report their opinion.’ The -committee thus nominated embraced all the most eminent men of the -day who had studied the phenomena of electricity, and in the order -in which they ranked. Next to the great discoverer of the lightning -conductor himself, Dr. Watson could claim to stand; and next to him Mr. -John Canton, a most painstaking and intelligent worker in the field, -inventor of the pith-ball electrometer, and other instruments. - -But a curious element of discord pervaded from the first this small -conclave of learned men, chosen to decide the not unimportant question -as to the best means of providing the cathedral of St. Paul with -lightning conductors. That the noble building should be so protected, -all were agreed; and it was clearly understood, besides, that if once -St. Paul’s had lightning conductors, all the other cathedrals and -principal churches of England would follow suit. What they differed -upon was not this, but the best form of lightning conductors. -Franklin’s steadfast assertion that points to the elevated rods were -not only far preferable to any other form of conductors, but the only -really protective ones, was adopted by Dr. Watson and Mr. Canton; but -they were opposed by Mr. Wilson, who asserted, with some degree of -vehemence, that points were dangerous, and that balls on the summit of -the rods afforded infinitely better protection. Standing alone in this -view among the eminent members of the committee of the Royal Society, -his arguments naturally had no effect, and the recommendation to the -Dean and Chapter of St. Paul’s was to protect the cathedral by pointed -lightning conductors. This was done accordingly. ‘Franklin rods’ were -attached to Wren’s splendid structure, worthy to be the introducer of -them, on a large scale, in Europe. - -The dispute as to pointed conductors, or balls, was by no means brought -to a termination by the decision that was come to regarding St. Paul’s. -Endless pamphlets were published on the subject, and it went so far as -to being turned into a political question. As priests scented heresy -in the daring attempt to draw lightning from the clouds, so the court -faction and ultra-conservatives of England smelt republicanism in the -erection of iron rods designed by the representative of the disaffected -American colonies. The king was understood to have given his own high -opinion entirely against points, and in favour of balls, declaring his -preference by ordering a cannon ball of large size to be placed on -the top of a conductor erected over the royal palace at Kew. Meeting -such high patronage, the ‘anti-Franklinians’ only sought an occasion -to break out into open scientific warfare, and they were not long in -finding it. On May 15, 1777, a large public building at Purfleet, on -the Thames, serving as a storehouse for war material, was struck and -greatly damaged by lightning, although protected by a pointed lightning -conductor. Thereupon arose an instant outcry against the system -advocated by Dr. Franklin. From much evidence adduced, there could be -no doubt that the building at Purfleet had been hurt simply because the -conductor was defective in parts, and was besides not laid deep enough -into the ground; still this did not stop the clamour raised. Chiefly -through the agitation of Mr. Wilson, the members of the Royal Society -entered into hot discussions about the respective merits of pointed -and round conductors. The feeling of the partisans of the latter side -ran so high on this occasion, that Sir John Pringle had to resign the -presidency of the Royal Society, which post he had ably filled since -1772, for making himself an advocate of points against balls. When the -fever of the learned men had cooled down a little, it was resolved to -settle the great question of points _versus_ balls by a series of -experiments, to be held in the Pantheon, a large building in Oxford -Street, dome-like in the interior. The arrangement, in fact, carried -out under the direction of Mr. Wilson, leader of the ‘ball’ party, was -to create an artificial thunderstorm--or, as it should properly be -called, ‘lightning storm’--by means of powerful electrical batteries, -to be discharged upon conductors of various forms. His Majesty George -III., greatly interested in the subject, and cherishing fond hopes that -cannon-balls would carry off the victory in the scientific dispute, -as well as in the graver political one with Franklin’s countrymen, -undertook to pay all the expenses of the Pantheon experiments, and -they took place accordingly on an elaborate scale. But though prepared -entirely with a view of showing the inefficiency of Dr. Franklin’s -points, they proved absolutely the contrary. Artificial, like real, -lightning clearly showed its preference for a lancet over a ball; it -would glide down the former quietly, but fall heavily, mostly with an -explosion, upon the latter. However, the question being in reality less -a scientific controversy than a dispute arising from the fiery heat -of political passions, it was by no means set at rest by the Pantheon -trials. ‘Franklin rods’ were more than ever abhorred by a multitude of -persons, learned and unlearned, after the great citizen of Philadelphia -had set his hand, on July 4, 1776, to the declaration of independence -of the ‘United States of America,’ and more than a quarter of a century -had to elapse, a new generation of men growing up, before there arose -clear and unimpassioned views about lightning conductors. - -While thus the battle of the rods was being fought in England, it raged -no less hotly on the continent of Europe. Here there was religious -prejudice alone at work, the political sympathies running in favour -of anything coming from America. But priestly animosity by itself -proved as strong an obstacle as any other to the erection of lightning -conductors. Where it did not exist, they sprang up with rapidity; but -wherever its influence was felt, the movement was arrested. In the -most enlightened parts of Germany, the seat and home of Protestantism, -the ‘Franklin rods’ early made their appearance. The first lightning -conductor set up over a public building in Europe was erected early -in 1769 on the steeple of the church of St. Jacob, Hamburg; and so -rapid was the spread of them that, at the end of five years from -this date, there were estimated to be over seven hundred conductors -within a circle of ten miles of the old Hanse town. To this day -they are comparatively more numerous in this district than anywhere -else in Europe. In contrast with Northern Protestant Germany, the -Roman Catholic South refused the ‘Franklin rods,’ and so did France, -although making a hero of Franklin personally. For many years after -young Robespierre pleaded the case of lightning conductors before the -tribunal of St. Omer, the strongest abhorrence to them was expressed -by the priests and their mob following in almost all parts of France, -and the active antagonism did not cease till after the outbreak of the -great revolution. - -It was the same in most countries of southern and central Europe. Even -in Geneva, famous for the enlightenment of its citizens, the populace -made an attempt to pull down the first lightning conductor. It was -erected, in the summer of 1771, by the celebrated naturalist, Professor -Horace de Saussure, over his own house, after directions furnished -by Dr. Franklin. But notwithstanding that the professor was himself -highly respected, his lightning conductor created general abhorrence, -and to appease it he found it necessary to issue a public address or -‘manifesto,’ as he called it, to his fellow-citizens. The address, -dated November 21, 1771, was strangely characteristic of the times. ‘I -hear with regret,’ Professor de Saussure declared, ‘that the conductor -which I have placed over my house to protect it against lightning, as -well as to observe, occasionally, the electricity of the clouds, has -spread terror among many persons, who seem to fear that by this means -I draw upon the heads of others those dangers from which I myself -wish to escape. Now, I beg you to believe that I would never have -decided upon erecting this apparatus, if I had not been fully persuaded -both of its harmlessness and its utility. There is no possibility of -its causing damage to my own house, or of doing harm to others. All -those who are now labouring under fear would be precisely of the same -opinion, if they had entered upon the same inquiries to which I am -called in the course of my studies.’ After which the professor goes -on minutely to describe the ‘electric conductor,’ which he had been -bold enough to place over his house, dwelling upon the fact of its -having protected, as he believed, already his own residence from being -struck by lightning, and of having been found, likewise, universally -efficacious in the same manner in ‘the English colonies of North -America.’ The citizens of Geneva, much given to reasoning, earnestly -read and studied the ‘manifesto’ of Professor de Saussure, and the -consequence was, not only that he was spared further attacks and -reproaches, but that there arose soon over the churches and houses of -the town some hundreds of lightning conductors. - -In Italy the progress in the erection of conductors was accompanied -by some very curious incidents. The priests here, as in other Roman -Catholic countries, actively opposed their introduction, and to do -so more effectively, they craftily attached to them a stinging name, -calling them ‘heretical rods.’ As a consequence, the mob fiercely -opposed the putting-up of any such accursed pieces of metal, and -whenever the attempt was made to fasten them to houses, it met -with forcible opposition. However, some of the highly accomplished -professors of the universities of Italy, enthusiastic in their -reception of Franklin’s discovery, proved themselves victorious -over both priests and mob. They got the Grand Duke Leopold of -Tuscany--subsequently German Emperor, under the title of Leopold I.--a -man of high scientific acquirements, to place lightning conductors -over his own palace, as well as over all the powder magazines in his -dominions. Here the mob and priest rule ceased, and only silent -curses could be levelled against the ‘heretical rods.’ Another still -more important step in advance was made by the influence of the -Abbé Giuseppe Toaldo, a warm admirer of Franklin, in correspondence -with him, and author of various scientific works, among them one on -lightning conductors. He had some influence with the ecclesiastical -authorities at Siena, in Tuscany, and brought it to bear upon them by -getting them to consent to make trial, in a manner so as not to excite -public attention, of one of the ‘heretical rods,’ over the cathedral. -This was only permitted on account of the extreme danger in which the -edifice stood, having been struck several times by lightning, and -greatly damaged. Placed on the summit of the highest of the three hills -on which stands the ancient city of Siena, the cathedral was opposed -to the dangers brought in the womb of every passing thunderstorm, and -they were all the greater as the building, erected by Pisano in the -thirteenth century, was deemed to be priceless, being one of the most -magnificent structures of the kind in Italy, of red and white marble, -filled with the choicest specimens of art, statues, pictures, gold and -jewelry. It seemed well worth risking a little heresy to guard such -treasures. - -Very silently, in the dark of night, the priests of the Siena -cathedral, directed by Abbé Toaldo, laid their iron rods along the -walls of the building, but inside, planting them deep into the -ground, and with the pointed summit only a few feet above the highest -point of the steeple, so as to be scarcely perceptible from below by -the naked eye. Still the secret of what had been done could not be -entirely kept from the multitude. Some of the workmen, engaged in the -operation of fixing the iron rods to the inner walls and steeple of the -cathedral, whispered about what they had been doing, trembling at the -evil consequences of their work, notwithstanding having received full -absolution from their employers. Murmurs were now heard everywhere, -and there were signs of a popular outbreak, just when one of the many -thunderstorms regularly visiting the mountain city crept over it on -April 18, 1777. Portentously the black clouds laid themselves thicker -and thicker over the high cathedral, till all the people of Siena -crept forth from their houses, awaiting in breathless expectation the -terrors to come. Then the dark masses discharged their fiery streams; -flash followed flash, till one, a long hissing tongue of flame, fell -down upon the cathedral steeple, distinctly visible to thousands -of beholders. A few minutes after, a ray of sunshine pierced the -dark clouds, and to the bewildering astonishment of the masses, the -cathedral was standing there absolutely unhurt. As if to exhibit its -wonderful power, the gilded point of the lightning conductor stood -out brilliantly in the sun, pointing in radiant silence up to heaven. -‘Maraviglia, maraviglia!’ cried people and priests in chorus. High -mass was held forthwith in the wonderfully preserved cathedral, and -on the same day the magistrates of Siena went into the town hall and -had a record made in the book containing the annals of the city, to -make known to all posterity that their noble cathedral had just been -preserved from destruction by the astounding influence of an ‘heretical -rod.’ Though not in the least intended to be sarcastic, the irony could -not have been more complete. - -There was a most remarkable historical concurrence between the gradual -introduction of lightning conductors into Europe and that of the art of -vaccination. Both the great scientific discoveries had the same end in -view for the benefit of mankind, the one teaching the art of drawing -the dangerous electric fire of the clouds harmlessly into the earth, -and the other that of extracting the poisonous seed of disease from -the human body. Both were brought forward with the noblest intentions; -and both encountered the most violent opposition from religious -fanatics, the same in substance, as interfering with the decrees of -Providence, and the ordained wrath of heaven. Both triumphed in the -end, and almost exactly at the same time, though the battle of the -great medical discovery lasted longer, and was more fiercely fought -than that of Franklin’s invention. To make the analogy between the -progress of lightning conductors and of vaccination complete, it so -happened that in at least one conspicuous instance the same man was -an important agent in forwarding the success of both discoveries. The -person in question was Dr. Johan Ingenhousz, a native of Breda, in the -Netherlands, born in 1730. A man of great natural gifts, he came to -England when about thirty years of age, practising as a physician, and -attending specially to the so-called Suttonian method of inoculation -against the small-pox, then an entirely new branch of medical science. -At the same time he eagerly embarked in electrical experiments, got -into correspondence with Benjamin Franklin, and, having made many -friends, was elected a fellow of the Royal Society in 1769. Recommended -to the king, Dr. Ingenhousz became a favourite at court, owing chiefly -to his perfect knowledge of German, which resulted in his being -recommended to a highly profitable as well as distinguished mission. -The famous Imperial lady, the Elizabeth of her age, Maria Theresa of -Austria, had read of the benefits of vaccination, then chiefly known in -England, and wishing to confer them on her own family and friends, she -asked King George the Third to recommend to her some able physician, -who could come to Vienna for the purpose. His Majesty at once named Dr. -Johan Ingenhousz, a recommendation warmly supported by the President of -the Royal Society, Sir John Pringle, who had taken an affection for the -young Dutch physician on account of his electrical researches, which -had resulted in the invention of a novel apparatus, subsequently known -as the plate electrical machine. - -Dr. Ingenhousz set out for Vienna in 1772, was received with marked -honours by the great Empress, and having done his work, and wishing to -visit Italy, received an autograph letter of Maria Theresa to her son, -Grand Duke Leopold of Tuscany. At the court of this enlightened prince, -Dr. Ingenhousz resided for some time, practising vaccination, but also -engaged in electrical experiments, which created the greatest interest. -It was partly by his advice that the Grand Duke consented, in the -teeth of desperate priestly opposition, to erect one of Franklin’s -lightning conductors over his own palace, and to set them up likewise -for the protection of all the powder magazines in Tuscany. This done, -Dr. Ingenhousz went forward to Padua, invited by some of the professors -of the university, and by the famous senator of Venice, Angelo Querini, -who had a magnificent palace in the neighbourhood of the city. In this -palace, bearing the name of Altichiera, the ‘English doctor,’ as he -was called, was made to reside, practising vaccination, the same as -at the court of Florence, but following as a favourite occupation the -setting-up of ‘heretical rods.’ Altichiera itself had the first erected -in May 1774, and soon after Dr. Ingenhousz had the satisfaction of -planting another over the astronomical observatory of the university -of Padua, in the presence of an enormous crowd of students who lustily -applauded, and of an angry multitude, kept in the background less by -persuasion than the strong arms of the young men. As at Siena, so at -Padua, the mob became pacified not long after by seeing the lightning -fall upon the observatory, much exposed by its situation, and which had -often been struck before, without doing the least damage. From Padua, -Dr. Ingenhousz went to Venice, in company of his friend and patron, -Senator Angelo Querini. Here his efforts to spread the knowledge of -lightning conductors, together with vaccination, had the best results. -The church of St. Mark and other public buildings were surmounted -before long by the awe-striking ‘heretical rods,’ and on May 9, 1778, -the Senate of Venice issued a decree ordering the erection of lightning -conductors throughout the republic. It was the first recognition of the -value of conductors by any government of Europe, or, indeed, of the -world. - - - - -CHAPTER V. - -METALS AS CONDUCTORS OF ELECTRICITY. - - -In the history of human inventions and discoveries, the idea of the -lightning conductor is almost the sole one which sprang, all but -perfect, from one brain, like Minerva, in Greek mythology, from -Jupiter’s head. Benjamin Franklin discovered the lightning conductor, -and, except some important improvements in its manufacture, due -to the progress of the metallurgical arts, the conductor remains -the same, in essence, as designed by the world-famous citizen of -Philadelphia. The reason of this is plain enough. Though one of the -most brilliant discoveries in the annals of mankind, the lightning -conductor, by itself, is one of the simplest of things. Franklin -found by experiments, that the mysterious so-called ‘electric fluid’ -had a tendency to make its way in preference through metals, and so -he recommended the laying-down of a metallic line from the clouds to -the earth to prevent damage to surrounding objects, such as buildings -and the human beings within them. More than this he did not know; and -more than this we, to this day, do not know. Of the inner nature, or -constitution, of that grand cosmic discharge of electricity to which -the name of lightning is given, no scientific explanation can be given. -We are utterly ignorant of it, and in all probability ever will be. - -But while the general principle laid down by Franklin, that metals -will conduct the electric force harmlessly from the clouds to the -earth, remains the same, very much has been learnt, in the progress of -scientific investigation, as regards the varying conducting capacity of -different metals. The first conductors were invariably rods of iron, -this metal being preferred by Franklin and his immediate followers -as cheap, ready at hand, and answering all purposes in practice. But -it was gradually found by experiments that there are other metals -through which the electric force will make its way more rapidly than -through iron. One of the earliest investigators of this subject was -Sir Humphrey Davy, the celebrated inventor of the miner’s safety lamp. -It was while studying the decomposition of the fixed alkalies by -galvanism, and tracing the metallic nature of their bases, to which -he gave the names of sodium and potassium, that the great chemist -and natural philosopher was brought to enter upon an examination of -what may be called the permeability of the different metals by the -electric force. The result of his investigations, as stated by him, -was that silver stood highest as a conductor of electricity; next to -it coming copper; then gold; next, lead; then platinum; then the new -metal called palladium--discovered by Wollaston, 1803, in platinum--and -lastly, iron. These were the principal metals experimented upon by -Sir Humphrey Davy, and the net result of his inquiries was expressed -summarily in the fact of copper being more than six times, and silver -more than seven times, as good a conductor as iron. Taking copper at -100, Sir Humphrey Davy drew up the following table of the electrical -conductivity of the seven metals:— - - Silver 109·10 - Copper 100·00 - Gold 72·70 - Lead 69·10 - Platinum 18·20 - Palladium 16·40 - Iron 14·60 - -The practical result of these experiments was that it came to be -recognised that, among the metals, copper might be employed to -greater advantage as a lightning conductor than iron: a much lesser -substance of it doing the same service of passing a given quantity of -electricity from the clouds harmlessly into the earth. - -Sir Humphrey Davy was followed in his researches on the conductivity -of the different metals by the electric force, by a number of other -scientific men. His immediate successor in entering upon this line -of observations was a French naturalist of eminence, Antoine C. -Becquerel. Perhaps no man after Benjamin Franklin studied the phenomena -of electricity with such thorough insight, free from all misleading -theoretical delusions, as Becquerel. He was educated at the Polytechnic -School of Paris, and in 1810, at the age of twenty-two, entered the -army as an officer of engineers, but quitted it five years afterwards -with the rank of colonel, to devote himself entirely to scientific -pursuits. Geology and mineralogy first engaged his attention, but he -soon quitted these studies to devote himself, heart and soul, to the -observation of the phenomena of electricity, which fascinated him as -much as they had done Benjamin Franklin. The result was the discovery -of a great many facts previously unknown, making Becquerel, amongst -others, one of the founders of the science of electro-chemistry. -The result of his researches concerning the conducting power of the -electric force by different metals may be stated as follows: - - Copper 100·00 - Gold 93·60 - Silver 73·50 - Zinc 28·55 - Platinum 16·40 - Iron 15·80 - Tin 15·50 - Lead 8·30 - Mercury 3·45 - -It will be seen, in comparing this statement with the result of the -investigations of Sir Humphrey Davy, that while the latter places -silver before copper in conductivity, Becquerel puts copper at the -head of the list. Probably, the explanation of this difference in the -result of scientific research, by two men equally learned and equally -able, may be found in the fact that the conductivity of copper varies -greatly according to the purity of the metal. It has been ascertained -that absolutely pure copper of the finest kind--such as that existing -in the Isle of Cyprus, youngest of mother Britannia’s colonial -children--has a conducting power of upwards of twenty per cent. more -than the ordinary copper of commerce. While thus arriving at different -estimates, Sir Humphrey Davy and Becquerel are singularly in agreement -in one important respect: they both make the relative electrical -conductivity of copper and iron about the same, placing it, the one a -little under, and the other a little over 100 to 15. In other words, -they both say that the value of copper as a lightning conductor to iron -is as twenty to three, or between six and seven times as great. - -Among a host of other investigators of the subject there stand -forward, besides Sir Humphrey Davy and Antoine Becquerel, two Germans, -Professors Lenz and Ohm, and another French savant, Claude Pouillet. In -the opinion of many scientific authorities, especially in the United -States, the experiments of Professor Lenz regarding the comparative -electrical conductivity of different metals were more carefully made -than any other, and are therefore deserving of the greatest credit. -He had, indeed, ample means and great leisure at his disposal, making -his scientific investigations under the patronage of the Grand Duke, -afterwards Emperor, Nicholas of Russia, while acting as his private -tutor at the university of St. Petersburg. The researches of Professor -Lenz as to the comparative power of various metals to conduct the -electric force were given in the following results--copper, as before, -standing as the centesimal unit:— - - Silver 136·25 - Copper 100·00 - Gold 79·80 - Tin 30·84 - Brass 29·33 - Iron 17·74 - Lead 14·62 - Platinum 14·16 - -A comparison of the figures here given with those of Sir Humphrey -Davy and of Becquerel shows that the results obtained by Professor -Lenz differ from those of both the other investigators. Like Sir -Humphrey Davy, Professor Lenz declared silver to be of greater electric -conductivity than copper, but, on the other hand, he assigned lead a -very low place, putting it under iron, instead of far above it. It is -difficult to explain this wide divergence, even on the utmost allowance -of purity, or impurity, of metals. As regards the most important -question, from a practical point of view--that of the difference -between copper and iron--Professor Lenz, it will be noticed, places -iron higher in the scale than both Sir Humphrey Davy and Becquerel. -Still, in his estimate also, copper was admitted to have about six -times the conductive power of iron. - -While, as just stated, the experiments of Professor Lenz on the -electric conductivity of metals are held in the highest esteem in -America, the same is the case in Germany as regards those of Professor -Ohm. The latter is held to be there the highest authority on all -subjects connected with the measurement of the electric force. The -professor, born at Erlangen, 1787, and for many years teacher of -natural history at Munich, where he died in 1854, devoted the utmost -patience and an immense amount of time to the definite object of -ascertaining the electric conductivity of all the metals, registering -the result of his experiments in a special work, the most complete -existing on the subject. According to Professor Ohm, the principal -metals stand to each other in conductivity as follows:— - - Copper 100·00 - Gold 57·40 - Silver 35·60 - Zinc 33·30 - Brass 28·05 - Iron 17·40 - Platinum 17·10 - Tin 16·80 - Lead 9·70 - -Here again is a striking difference with the statements of other -investigators. It seems absolutely inexplicable indeed, how it could -happen that scientific men of eminence, and admitted authorities on the -subject they are treating, came to vary on the electric conductivity -of several of the metals. The difference is most astounding as -regards silver, the conductivity of which, compared with the per -cent. of copper, Professor Lenz places at 136·25, Sir Humphrey Davy -at 109·10, Becquerel at 73·50, and Professor Ohm at only 35·60. The -only conclusions that can be come to under the circumstances are, that -the record of Professor Ohm’s results as regards silver is incorrect; -or, that the relative degrees of purity of the samples of metal -experimented upon by him and the other professors differed very widely. -What is of more importance than this question, is the comparative rank -of copper and iron. Here, it is satisfactory to find, the results -ascertained by Ohm agree very nearly with the conclusions of the other -investigators, it being laid down that copper has about six times the -conductive power of iron. - -The place filled in America by Lenz, and in Germany by Ohm, is -generally assigned in France to Professor Claude Pouillet, a savant who -devoted, perhaps, more time than any other in his own country to the -study of the phenomena of electricity. Born in 1791, Professor Pouillet -became, at a comparatively early age, the director of the celebrated -scientific institution of Paris known as the ‘Conservatoire des arts -et métiers,’ which led him to enter upon a course of experiments in -electricity, and most particularly, at the request of the government, -upon investigations as to the best material for lightning conductors. -The result of these was published in a lengthened treatise, in which -Professor Pouillet set down the electric conductivity of the principal -metals, taking copper at a hundred, as follows:— - - Gold 103·05 - Copper 100·00 - Silver 81·26 - Brass from 23·40 to 15·20 - Platinum 22·50 - Iron from 18·20 to 15·60 - Cast Steel 14·75 - Mercury 2·60 - -It will be seen that Professor Pouillet, differing from other -investigators, as they among themselves, regarding the relative -conductivity of the precious metals, gold, silver, and platinum, agreed -in the main with them as regards the relative proportions of copper -and iron. Most painstaking and minute in his experiments, he found -moreover that iron, as well as brass--the latter a mixed metal, and -as such variable in composition--was not always the same in respect -to conductivity, the changes being due to difference in temperature, -as well as greater or lesser metallic purity. As set down by him, -the variations in iron were between a maximum of 18·20 in regard to -100·00 of copper, and a minimum of 15·60, which gives a mean of 16·90. -Taking this mean, the comparative list of the positions held by copper -and iron in regard to electrical conductivity, according to the five -investigators, may be set forth in the following summary:— - - Copper Iron - Davy 100·00 14·60 - Becquerel 100·00 15·80 - Lenz 100·00 17·74 - Ohm 100·00 17·40 - Pouillet 100·00 16·90 - -Taking the average of these five statements, it will be found that the -relative conductivity of copper to iron stands as 100 to 16½--that is, -a little over six to one. The approximate correctness of this figure, -being the result of all the investigations by the most eminent men who -studied the subject, can therefore admit of no reasonable doubt. - -The important researches as to the greatly varying degree in which -given quantities of metals will act as conductors of the electric -force, were made possible only by the discovery of the singular -phenomena of electro-magnetism, due chiefly to the Danish philosopher -and naturalist, Hans Christian Oersted. His career, in some respects, -was not unlike that of Benjamin Franklin. The son of an apothecary, -born in 1777, he set up in the same business, not despising trade, but -devoting himself actively to it, as means to an honourable end, that -of gaining independence. Fascinated by the study of the phenomena of -electricity, Oersted devoted himself to it heart and soul, as Franklin -had done; and the result achieved, if not fully as important as the -invention of the lightning conductor, was one filling a prominent place -in modern scientific discovery. It had been observed, long before -Oersted, that there was a close connection between what was known as -magnetism and lightning, or rather, to state it more directly, it was -known that lightning exercised a strong influence upon the magnetic -needle. One of the most notable reports, and one of the first on the -subject, came from the captains of two English vessels, sailing in -company from London to the West Indies in the year 1675. When near -the Bermudas, a stroke of lightning fell upon the mast of one of the -vessels, doing considerable damage, and, as the captain believed, -swinging his ship round, the men at the helm seeing the compass -violently disturbed. He continued steering in what he believed the -old direction, but noticed, a few minutes afterwards, that the other -vessel, his former companion on the route, and which had not been -struck by lightning, was following an opposite course. He had the good -sense to approach it, and explanations ensued, the result being the -discovery that the lightning had completely reversed the polarity of -the magnetic needle, it pointing now south instead of north. The story -of this met with much doubt at the outset, but it was amply verified -before long by the report of many similar occurrences. It became -known, not only that the polarity of the magnetic needle might be -reversed by a stroke of lightning, but that the effect of the latter -frequently was to magnetise iron and steel. An instance of this kind, -on a large scale, occurred at Wakefield, Yorkshire, in the month of -June 1731, during a violent thunderstorm. The lightning here entered -the warehouse of a merchant who had just packed a case of knives, -forks, and other articles of steel and cutlery ware, for despatch to -the colonies. The case was placed immediately under the chimney, which -the lightning entered, breaking open the box, and scattering over -the floor of the room its contents, which, when afterwards examined, -were all found to be strongly magnetic. These, and many similar facts, -were all clearly established; yet a considerable time elapsed before -important conclusions were drawn therefrom. As in the case of Franklin, -so in that of Oersted, it required not merely scientific acumen, but a -thoroughly practical mind, to trace, in the one instance, the actual -connection between electricity and lightning, and in the other that -between magnetism and electricity. - -It was in the year 1819 that Hans Oersted, now settled as a lecturer at -Copenhagen, announced the result of a series of investigations which -laid the foundation for the new science of electro-magnetism. He stated -that he had found that if a magnetic needle, free to move like that of -a compass, was brought parallel to a wire charged with electricity, -it would leave its natural place and take up a new one, dependent on -the position of the wire and the needle relative to each other. If -the needle, he said, was placed horizontally under the wire, the pole -of the needle nearest the negative end of the electric battery would -move westward, but, on the other hand, if the needle was placed above -the wire, the same pole would move eastward. Again, if the needle was -placed on the same horizontal plane as the wire, no motion would be -on that plane, but the inclination would be to a vertical movement. -Finally, if the wire was laid to the west of the needle, the pole -nearest the negative side of the battery would be depressed, but it -would be raised if the wire was placed to the east of the needle. -From these observations, verified in numerous experiments, Oersted -concluded that the magnetic action of the electric force moved in a -circular manner around the conducting object, which he expressed in -the formula that ‘the pole _above_ which the negative enters is turned -to the west,’ and that ‘the pole _under_ which it enters is turned -to the east.’ The discoveries of Oersted resulted in the creation of -that wonderful production of modern science--the electric telegraph. -A minor result, highly important as regards the erection, and still -more the maintenance, of lightning conductors, was the construction of -galvanometers. - -What the microscope is to the student of the inner secrets of animal -and vegetable life, the galvanometer is to the investigator of the -phenomena of electricity, in their practical applications. Until its -invention, there existed no means of practically testing the strength -of the electric force, or the ‘current,’ as it is usually called, -and it was not possible, therefore, to ascertain, in any given case, -whether lightning conductors, among others, were really efficient or -not. Perhaps, had it been only for this purpose, the galvanometer -would have waited long in being constructed, but what brought it into -existence, and led it to its present perfection, was that greatest of -practical uses of electricity, the telegraph. As it arose from small -beginnings to gradually more extended employment, embracing ultimately -some of the highest interests of civilised mankind, there came the -necessity of having instruments for gauging accurately the effects of -the mysterious force thus put in harness at the bidding of science. -The galvanometer having been devised, the next step, indispensable for -its use, was to frame a standard by which electrical energy might be -measured, and to invent terms by which the amount of such energy could -be expressed. It is well known that in order to be able to measure the -dimensions of any material object, standard units are required. In this -country the units adopted are: for length, the foot; for weight, the -pound; for time, the second; and so on. To express mechanical force or -power, the foot pound is the unit employed--that is, the mechanical -energy necessary to raise a weight of one pound to a height of one -foot. On the Continent, where the units of length and weight are the -metre and the gramme, the unit of mechanical energy is the metre -gramme. Apart from the fact that the latter units are very generally -adopted by all the Continental States, the simplicity of the decimal -method of multiplying and sub-multiplying them renders the system of -particular usefulness for scientific purposes; and they are therefore -very extensively employed even in England in scientific research. Thus -experimental results obtained in one country are at once understood, -and are directly comparable with results obtained in any other country, -without the necessity of reducing the figures to terms of units of -other kinds than those in which they are expressed. - -Now electrical energy being merely a form of mechanical energy--the one -being capable of conversion into the other--it follows that the units -of the functions of either of the two powers can be expressed in units -of the other; and this being the case, it is manifestly both convenient -and desirable that in forming the dimensions of the standard electrical -units, they should be constructed in terms of the metre gramme, second -units. - -The proposition to do this originated with Dr. Weber, and acting upon -this proposition a committee of the British Association, comprising -nearly all the leading electricians of Great Britain, was formed some -years ago, which committee, with almost perfect experimental skill, -determined an absolute measure for the values of the several units -required for electrical measurement. Taking as the unit quantity of -electricity that amount which would be generated by a gramme weight -falling through a distance of one metre in one second, the value given -to the unit of resistance was such as would allow this unit quantity -to flow through it in one second. The means by which the values were -experimentally arrived at cannot be described here. It suffices to say, -that the unit of resistance being once determined, copies of it, formed -of lengths of wire of a platinum-iridium alloy, were issued, from which -copies the sets of resistances now so largely employed by electricians -were adjusted. Out of compliment to the great German physicist who -first proposed the fundamental law which governed the flow of the -electrical current, the unit of resistance was called the ‘Ohm.’ It was -a marked progress on the practical application of the electric force -to be enabled to measure it, and, as it were, bring it under control. - -Without its help the electric telegraph could not have become what -it is; nor has it been without notable use in the art of protection -against lightning. One of the greatest steps in advance in the -application of the lightning conductor, from its discovery to the -present day, has been the invention of the galvanometer. Franklin could -not, but we can, test our lightning conductors. - -[Illustration: Fig. 1.] - -[Illustration: Fig. 2.] - -Some of the simplest and most practical galvanometers, specially -designed for ascertaining the actual efficiency of conductors, have -been made in recent years in Germany. The author of this work had -constructed for him by Mr. H. Yeates, of Covent Garden, the one, with -some improvements, as shown in the subjoined engravings: the first, -fig. 1, exhibiting the arrangement of the battery and resistance coils, -and the second, fig. 2, giving a diagram of the battery current. The -battery consists of three cells, and is a modification of the old -manganese cell, in which the carbon and oxide of manganese occupy -the outer, and the zinc plate the inner, or porous, cell. By this -arrangement, the surface of the negative element is greatly increased, -and hence a more constant current is obtained, on account of the -battery not polarising so rapidly as in the old form. Another advantage -of this arrangement is, that the cells can be almost entirely sealed -up, the air-openings being made within the porous cell. In the centre -of the lid of the box is placed the galvanometer with a ‘tangent’ -scale; and on the left are two terminals, by the connection of which -the conductor can be examined. On the right hand end of the lid are -placed five keys, marked respectively, L, B, 1, 2, 3. Under B is -one pole of the battery, so that by depressing this key, as will be -seen by the connections in the diagram (fig. 2), the battery current -is sent through the galvanometer direct. If, however, key No. 1 is -depressed, the battery is connected with the galvanometer through a -known resistance--key No. 2 has a larger resistance, and No. 3. still -larger. The fifth key, L, closes the circuit within the limit of the -instrument, but on being depressed opens it, and includes the line -or conductor placed between the two terminals at the other end, the -battery key at the same time being pressed down. By this arrangement -it will be seen that the resistance of the line or conductor may be -compared with the known resistance connected with any of the keys -Nos. 1, 2, 3, or any of these resistances may be included with that -of the line, so as to get a convenient deflection of the galvanometer -needle. In the case, with the battery, is a bobbin of insulated wire -for connecting the instrument with the conductor and earth which is -to be tested. The whole arrangement here described and illustrated -is exceedingly portable, being in the form of a small carpet bag, -and therefore particularly fitted for persons inspecting lightning -conductors and making periodical tests, without which it cannot be too -widely known there is really no trustworthy security of protection in -lightning conductors. - - - - -CHAPTER VI. - -CHARACTER OF LIGHTNING AND OF THUNDERSTORMS. - - -It is well remarked by Arago, that although we know nothing about -lightning, beyond the well-ascertained fact that it is one of the -manifestations of the equally vast and mysterious electric forces -pervading the universe, we yet may ascertain a great deal about -its mode of action by continued observation, made by many persons -and at many places. As yet the wise recommendation of the French -astronomer has, unfortunately, not been acted upon to any extent, -or in any systematic manner; still, a good many facts and incidents -have been gathered which serve to throw a strong light upon the -apparently erratic, but in reality normal manner in which, as in -obedience to some grand unfathomable cosmic law, the fire of the -clouds flashes along its self-made path. That these observations -are entirely modern, detracts nothing from their value. With all -their famed civilisation, the classical nations of the ancient world -never came to look upon lightning and thunderstorms as regular -functions of nature, but regarded them with dread and horror. Even -the greatest of their natural philosophers found in them means only -for encouraging popular superstition. Thus Pliny the Elder, in his -celebrated ‘Natural History,’ recommends, like Arago, notes being -taken about thunderstorms, but for quite a different purpose. ‘Nothing -is more important,’ says the celebrated author of the _Historia -Naturalis_, than to observe from what region the lightnings proceed, -and towards what region they return. Their return to the eastern -quarter is a happy augury. When they come from the east, the prime -quarter of the Heavens, and likewise return thither, it is the -presage of supreme felicity.’ It is reported by travellers that this -form of superstition--which has reference, of course, to the zigzag -form of many strokes of lightning, apparently in turn advancing and -retrograding--still exists in some districts of Southern Italy. - -The superstitious awe with which lightning was looked upon not only -in ancient times, but in which it is still held by the ignorant at -the present day, finds its easy explanation both in the nature of -the terrifying phenomenon, and in the fact that even now we can only -speculate upon some of the causes of its seemingly capricious actions. -There can be no doubt that thunderstorms will visit some districts -in preference to others, and that lightning will descend constantly -upon some selected spots, and will entirely keep away from others. -As regards the latter case, old historians were fond of quoting the -grand temple of Solomon at Jerusalem, which was never struck by -lightning in the course of a thousand years, although thunderstorms -burst unceasingly over the Holy City, creating immense havoc and -destruction. In this instance at least, the explanation is simple, -although it may not be so in many others. It is stated expressly in -the biblical description of the building of the world-famed temple (1 -Kings vi. 21, 22) that ‘Solomon overlaid the house within with pure -gold; and he made a partition by the chains of gold before the oracle; -and he overlaid it with gold. And the whole house he overlaid with -gold, until he had finished all the house; also the whole altar that -was by the oracle he overlaid with gold.’ If wise King Solomon had -known Franklin’s discovery of the protection against lightning given by -metallic conductors, he could not have guarded his magnificent edifice -better than he did by having ‘the whole house overlaid with gold,’ -as stated in the Bible. But he did even more than this, according -to the historian Josephus, who records that the roof of the Temple, -constructed in what is now called the Italian style, was ornamented -from end to end with sharply pointed and thickly gilded pieces of -iron, in lancet form. These points, the historian surmised, were -placed there to prevent the birds from settling on the magnificent -roof, and soiling it, and it is very possible that this was the -original design. Nevertheless, it is certain that King Solomon guarded, -although, probably, without intending to do so, his magnificent temple -as perfectly against lightning, as could have been accomplished by -the best arranged system of conductors. It is not often that many -thousands of pounds are spent for protection against lightning, even -if intended for great cathedrals and splendid royal palaces; but King -Solomon disbursed, by the most trustworthy calculations, no less than -thirty-eight millions sterling in covering the temple with one of the -best of conductors--including the pointed and gilded lancets along the -roof, as perfect ‘Franklin rods’ as were ever designed by any architect. - -If it is easy to account for the old historical marvel of Solomon’s -temple having stood unharmed amidst the ragings of lightning from -tens of thousands of storms, it is more difficult to find the reason -why many buildings of another kind should be constantly under attack. -A notable case in point, related by the German naturalist G. Ch. -Lichtenberg, occurred at the village of Rosenberg, in the province -of Carinthia, Austria, belonging to the noble family of Orsini. The -village church, although not standing in a very elevated position, was -unceasingly struck, in the course of the seventeenth and eighteenth -centuries, by lightning, which sometimes battered in the roof, -sometimes broke down part of the steeple, and often flew in at the -window on one side and out on the other. Very possibly, there were -large pieces of metal on the wall, or in the roof; or, if not, there -may have been masses of water near, underground, sufficient to account -for the manifestations of the electric force. However, popular opinion, -utterly ignorant as to such causes, ascribed the whole to the doings -of evil spirits, and endless attempts were made to exorcise them -by prayers, fastings, and sprinkling of holy water. But it was all -unavailing. The lightning came again and again, and in the summer of -1730, a flash from the clouds, more violent than any preceding one, -demolished the entire steeple. The Orsini family, suspected by many of -the lower people of being the secret originators of all the mischief, -in league with the evil spirits, erected another steeple, handsomer and -far more solid than the one destroyed, to show their pious intentions. -But the lightning visited it as before, on the average five or six -times a year, doing so much damage that the whole church had to be -taken down in 1778, being found in ruins. Happily, in the meanwhile -the report had gone as far as the little village in Carinthia that -something had been discovered for guarding all buildings, including -spirit-haunted churches, against damage by lightning. Once more, the -proprietors of the village built a new church on the old ground, but -this time, by the advice of an Italian architect, they placed upon it -one of the ‘heretical rods,’ made famous for having done good service -in protecting the cathedral of Siena. Needless to say that it did again -similar service. - -It is very probable that, besides the two causes just referred to which -divert the path of lightning, there are many others of influence, -at present entirely unknown. Numerous cases are reported where the -electric discharge from the clouds touched precisely, and with -singular accuracy, as if directed by a superior intelligence, the -same spot, without the slightest reason being discoverable for such -an action, after the most minute investigation by competent persons. -Thus, on June 29, 1763, a violent thunderstorm broke over the village -of Antrasme, near Laval, in France, the residence of a distinguished -investigator of electrical phenomena, Count de Labour-Landry, a friend -and correspondent of the Abbé Nollet as well as of Benjamin Franklin. -The lightning struck, as carefully ascertained by the Count, first -the steeple of the church, then sprang to one of the lower walls, -where it fused and blackened the gilding of picture frames and some -other metallic ornaments, melting also some pewter flasks used for -sacramental purposes, and finally opened two deep holes, as regular -as if they had been drilled with an auger, in a wooden table, placed -within a recess of soft stone. All these damages were duly repaired; -but, to the boundless surprise of the witnesses, the lightning struck -the church almost exactly a year after, on June 20, 1764, entering -the church by the same way as before, fusing and blackening the same -gildings, melting the same flasks, and, in the end, driving out the -very plugs of the wooden table inserted to fill the holes bored by -the previous stroke of lightning. The account of the whole might seem -almost incredible, were it not attested by independent eye-witnesses. -Arago, with absolute faith in their testimony, remarks thereon that -‘those who will take the trouble of reflecting upon the thousands of -combinations which might have caused the path of the lightning to have -been different in the two cases, will, I imagine, have no hesitation -in viewing, with me, the perfect identity of effect as demonstrating -the truth of a proposition I put forward,’ namely, that ‘lightning, in -its rapid march, is influenced by causes, or actions, dependent on the -terrestrial bodies near which it explodes.’ In other words, lightning, -like many other phenomena of earth, air, and water, is influenced by -unknown causes. Hamlet says very much the same, when exclaiming: - - There are more things in heaven and earth, Horatio, - Than are dreamt of in your philosophy. - -After all possible explanations, Arago could get no further than -Horatio, who thought that there was much in the universe which was -‘wondrous strange.’ - -It does not seem impossible that some of the extraordinary effects -of lightning, either in striking repeatedly certain objects, or in -seldom or never touching others, may be explained on meteorological -grounds. The height, as well as thickness, of the clouds charged with -the electric fire, must naturally greatly influence the direction of -the latter, and though both elements vary enormously, in different -countries and at different seasons, it is likely enough that the -variation is comparatively trifling under given conditions, as, for -example, in a district where there are prevailing winds, and where the -configuration of the earth powerfully acts upon the drift and movement -of the aerial masses, and the atmospheric conditions in general. As -to the height of the clouds charged with lightning, there appears -scarcely any limit, as it has been found that they at times rise above -the summit of the most elevated mountain ridges on the face of the -globe. The great naturalist and traveller, Alexander von Humboldt, -measured the height of a storm cloud, discharging lightning, near the -mountain of Toluca, in Mexico, and found that it was no less than -4,620 metres, or 15,153 English feet, above the level of the sea. The -height of another, ascertained by Professor de Saussure, of Geneva, -when ascending Mont Blanc, was 4,810 metres, or 15,776 English feet, -or almost exactly three miles. Probably, these are exceptional cases, -as even in mountainous districts the heavy moist and electricity-laden -clouds seldom rise to such extraordinary heights; still, even such -as they are they do not represent the extreme limit of elevation. A -member of the French Academy of Sciences, M. De Lisle, records having -measured, by trigonometrical observations, the vertical height of -clouds in a thunderstorm, with strong flashes of lightning, which broke -over Paris, and found it to be 8,080 metres, or 26,502 English feet. -Consequently, this cloud-mass, charged with electricity, stood far -above the summit of the highest mountain peak in the world. - -If some of the lightning-clouds tower at a gigantic elevation over the -earth’s surface, there are others that lie almost flat on it. There are -some remarkable observations on this kind in existence, made by German -meteorologists. Two of these deserve particular notice. On August 27, -a heavy storm burst over the town of Admont, on the river Ens, in -Styria, and the lightning, falling upon the lower part of the great -convent of the Benedictines, and passing through the wall, killed two -young priests near the altar, while reading vespers. The convent lies, -like the town of Admont, in a valley, and above it, some three hundred -feet higher, stands a castle, in which resided at the time a German -professor, specially interested in the phenomena of thunderstorms. He -watched assiduously the coming storm, and saw the lightning fall upon -the great convent, noticing all the while that the gilded cross placed -on the belfry of the edifice, about 115 feet from the ground, remained -standing out clear above the electric cloud, which appeared to come -close to the earth’s surface. He noticed further that above this cloud, -enveloping the ground portion of the Benedictine convent, there hovered -another, more than two thousand feet higher, and at intervals he could -see streaks of lightning fly from between the two, not however from the -more elevated to the lower one, but in a contrary direction. It was -evident that the two clouds must have been charged by electric forces -of different ‘degree,’ or ‘potential;’ it may be, one of a ‘negative’ -and the other of a ‘positive’ kind, or, as Benjamin Franklin termed -them, ‘plus’ and ‘minus;’ although, as long as the forces differ in -‘degree’ or ‘potential,’ it is not essential that they be of opposite -kinds. As the marvellously sagacious discoverer of the lightning -conductor surmised, the wondrous force is really unitarian--that is, -throughout the same, the term ‘kind’ really only indicating on which -side of an assumed zero (the potential of the earth) the observations -or measurements are made. - -Another notable instance of low-lying storm-clouds, and which furnished -the rare opportunity of measuring the thickness of one of them, -occurred at the city of Gratz, Austria, on June 15, 1826. The city is -built along the side of a hill, the highest point of which, called the -Schlossberg, has on its summit a castle, now in ruins, but at the time -garrisoned by troops, and furnished with a small observatory. When -the storm in question broke over the city, several scientific men on -the Schlossberg took notes of the movement and direction of the great -cloud emitting its electric discharges. This they could easily do, as -they themselves, on their altitude, were standing in sunshine, under -a perfectly blue sky, the dark cloud-wave rolling deep under their -feet, indicating its path and size by streams of fire, following each -other in rapid succession. Exclusive of short flashes, vanishing in -the air as soon as seen, there fell nine great strokes of lightning -upon buildings in the city, in the course of about three quarters of -an hour, five of them causing conflagrations and killing a number of -people. The storm over, the observers compared their measurements, and -it was then found that the height of the storm cloud had never been -above the clock-tower of the Johanneum, an edifice connected with the -university, and containing a library and museum, while the lowest part -of it had gone down the sloping ground of the city no further than 120 -feet under the summit of the clock-tower. This, then, was the exact -thickness of the storm-cloud which had caused so much destruction. -It was noticed on this occasion, as had been done often before, that -the discharges of lightning fell all upon buildings standing on moist -ground, near the river Mur, a mountain stream coming from the Noric -Alps, and dividing the city into two parts. There can be no doubt, from -thousands of observations made, that it is one of the characteristics -of the electric force to seek its way towards water--to be, as it were, -dissolved by it, or, as perhaps it might be said more truly, to be -equalised by it. A very remarkable electrical phenomenon, and one which -is often attended with fatal results to men and animals, is what is -known as the ‘return stroke’ of a lightning discharge. This is always -less violent than the direct stroke, but is nevertheless very powerful. -It is caused by the inductive action which a thunder-cloud exerts -on bodies placed within the sphere of its activity, and disastrous -effects often take place upon objects, upon men and animals on the -earth under the cloud, although perhaps miles away from the point -where the discharge takes place. These bodies are, like the ground, -charged with the opposite electricity to that of the cloud; but when -the latter is discharged by the recombination of its electricity with -that of the ground, the induction ceases, and all the bodies charged by -induction return to a neutral condition. The suddenness of this return -constitutes the dangerous ‘return stroke.’ - -Lord Mahon was the first to demonstrate by experiment its mode of -action; as shown in the following illustration. - -[Illustration] - -A B C is the electrified cloud, the two ends of which come near the -earth. The lightning discharge occurs at C. A man at F is killed by the -return stroke, while those at D, nearer to the place of discharge, but -further from the cloud, receive no injury. It may be mentioned that it -was the action of the return shock upon the limbs of a dead frog in -Galvani’s laboratory that led to the Professor’s experiments on animal -electricity, and further to the discovery by Volta of that form of -electrical action which bears his name. - -The subject of the origin of atmospheric electricity has at all times -been a favourite source of speculation with scientific investigators, -and given rise to numerous hypotheses. The eminent Swiss savant, -Professor de Saussure, already referred to, held that all atmospheric -electricity was due to the evaporation of the waters of the globe -through the effect of the sun. To prove this, he made a great number of -experiments, showing that whenever water, whether pure or containing -more or less salt, whether acid or alkaline, is projected upon a -metal crucible heated to redness, the evaporation that takes place -immediately is accompanied by strong liberation of electricity. The -fact is undisputed by scientific men, but not so the conclusion. -Another eminent savant, no less distinguished than De Saussure, -Professor De la Rive, in taking up the experiments of the former, -succeeded in showing that the production of atmospheric electricity -by throwing water upon heated metal was not the simple effect of -evaporation, but due to chemical causes. - -Of the numberless attempts made to elucidate the phenomena of -electricity, in connection with the formation of thunderstorms, none -seem more worthy of regard, and of thoughtful consideration, than -those of Jean Athanase Peltier, a French savant, little known to the -general world. Born in 1785, he occupied his whole life, until his -death in 1845, with the study of meteorology and electricity, making, -among others, the important discovery that a current flowing through -a circuit composed of two metals joined together heats or cools the -junction according to the direction of the current. From all the -experiments upon the phenomena of electricity, to which he devoted -his life, Peltier drew the conclusion that the earth itself, and more -particularly the fiery liquid mass forming the inner bulk of it, over -which the solid crust and the ocean lie, but both thinner in comparison -than the skin of an apple, form one immense reservoir of electricity. -As light comes from the sun, generated, as we believe, by heat, so -the electric force, he held, comes from the interior of the globe, -likewise generated by heat. The atmosphere surrounding the globe, -Peltier asserted, produced no electricity whatever, nor held it, except -temporarily. But he thought it possible that it might exist, engendered -by other flaming masses than those of the earth’s interior, in the -interminable planetary spaces, which no astronomer can measure, and of -which imagination itself, in its loftiest flights, can form no more -conception than the finite ever can of the infinite. On the whole, -Peltier’s explanation, such as it is, may fairly be accepted, in the -present state of the scientific investigation, as one of the best that -can be given. For the rest, men must content themselves to study the -phenomena of electricity, and to regard it simply as one of the great, -if mysterious, forces of nature. - -[Illustration] - - - - -CHAPTER VII. - -INQUIRIES INTO LIGHTNING PROTECTION. - - -From our present ignorance of the actual nature of electricity, -admitted alike by all scientific men, it has often been argued that no -claim can be set up for a perfect protection against the effects of -the electric force called lightning, since we do not know ‘whence it -comes, nor whither it goes.’ That this argument is entirely fallacious, -may be easily shown. The human mind does not understand, any more -than it does electricity, the great forces called centripetal and -centrifugal, which keep millions of suns and of planets in their path -through the boundless universe; yet there is no educated man who doubts -that astronomers are able to calculate, with the greatest mathematical -precision, the time when two particular stars will come near each -other, when the moon will obscure Orion, and Venus make her transit -across the sun. Again, no explanation can be given of the actual -nature, of the Why and the Wherefore, of the force called gravity, -simply in its operation on our globe. Still men can calculate, with -the greatest nicety, the result of any given weight, falling, from any -given height, on the surface of the earth or below it. - -François Arago, reasoning on the disputed efficiency of lightning -conductors, puts another indisputably practical case. ‘If,’ says he, -‘we take the dimensions to be given to conductors from experience, -and if those which we adopt have been found to resist the strongest -lightning recorded for over a century, what more can reasonably be -asked for?’ When the engineer decides on the height and width of -the arches of a bridge, the vault of an aqueduct, the section of a -drain, and similar constructions, what does he concern himself with? -He examines all the facts and records on the matter as extensively as -he can, and, in making his plan, keeps somewhat beyond the dimensions -dictated by the greatest floods and the heaviest rains which have ever -been observed. He thus goes as far back in his research as the evidence -within his reach will enable him to do, but without confusing himself -either with searching for the hidden causes of floods and rains, or -with investigating the character of the physical revolutions, or the -cataclysms which occurred in prehistoric times, and of which geologists -only have been able to discover the traces and estimate the magnitude. -So with the engineer. Greater precaution or foresight than his cannot -be demanded from the constructor of lightning conductors, nor is any -needed.’ - -It may be laid down as an absolute fact, that a well-made lightning -conductor, properly placed, and kept in an efficient state, can never, -under any circumstances, fail in its action. Undoubtedly it has -happened that buildings to which conductors were attached have, in many -instances--of which some will be enumerated in another chapter--been -struck by lightning, and even damaged; but these cases, so far from -going against the truth that good lightning conductors are infallible, -only serve to prove it. A close investigation of all known instances -where the electric force has struck buildings, nominally protected -against lightning, shows most conclusively that the conductors placed -on them were either inefficient, in some way or the other, or did not -lead properly into moist ground--that is, had not the all-indispensable -‘earth connection.’ There is no case on record in which a really -efficient lightning conductor, properly placed, and with its terminal -in technically so-called ‘good earth,’ did not do its duty; and without -being dogmatic on the subject, it may well be asserted can no more -fail to give protection than an efficient drain-pipe can fail to carry -off the water upon the roof. Although the electric force is neither a -‘current’ nor a ‘fluid,’ often as it is so described, still the analogy -holds good so far as the one here given between the drain-pipe and the -conductor. And the reason is clear enough. The water, in running down -a hollow tube, obeys simply the law of gravity, but no less immutable -than this is that which governs the movement of the electric force. As -the water has no choice but to follow the channel made for it, under -the guidance of experience and mathematical calculation, so has the -emanation of the electric energy no option but to pursue the path which -scientific investigation has shown it always to take. Men may speak of -‘erratic’ lightning; but it is certain that the course of the electric -force is as subject to cosmic laws and as immutable as that of the -stars. - -Most of the experiments and investigations for ascertaining the best -form of lightning conductors, and their application to buildings -so as to be invariably efficient, have been carried on by private -activity; still, the subject has also, at various times, undergone -the examination of official authorities, as well as of learned -societies. Little has been done in this respect in England, but very -much in France, where, ever since the publication of Franklin’s great -discovery, the question of protection against lightning has uniformly -interested the public, as well as the learned world, leading to -the production of more treatises on the subject than in any other -country, except perhaps Germany, the world’s centre of book-making. -One of the most important of the French works here referred to, and -which may be regarded as the standard work on lightning conductors, -is a semi-official publication, entitled ‘Instruction sur les -paratonnerres,’ issued in new editions from time to time, and widely -dispersed, not only in France, but all over Europe and America. It -consists of several reports about lightning conductors made, from -1823 to 1867, by committees comprising some of the most distinguished -men of science at the time, to the ‘Académie des Sciences’ of Paris. -The earliest of these reports originated from an application of -the French Government to the ‘Académie.’ In the year 1822, there -happened to be in France, and over the greater part of Continental -Europe, an extraordinary number of violent thunderstorms, accompanied -by earthquakes and simultaneous eruptions of Mount Vesuvius, the -latter on a scale not witnessed for centuries. In France, the almost -continuous thunderstorms caused great alarm among the population; -and the priests in many places held processions in and around the -churches, with special prayer-meetings, to ‘appease the wrath of -heaven.’ In consequence of all this excitement, the Minister of -the Interior, deeming that something also ought to be done besides -the walking in procession to stay the fatal effect of lightning, -ordered that all the public buildings in France should be protected -immediately by conductors, made on the most perfect model and placed -in the best manner. To get pre-eminent advice as to the efficiency of -lightning conductors, the Minister applied officially to the ‘Académie -des Sciences,’ which learned body thereupon nominated a committee -consisting of six of the most celebrated investigators of the phenomena -of electricity--MM. Poisson, Lefèvre-Gineau, Girard, Dulong, Fresnel, -and Gay-Lussac. The committee held many sittings, collecting a vast -amount of evidence on the subject, and on April 23, 1823, presented -through M. Gay-Lussac its report to the ‘Académie des Sciences,’ -which was adopted and ordered to be printed, being declared a highly -important document. The French Government took the same view as the -‘Académie des Sciences,’ and not only acted upon the recommendations -of the report, but issued it to all public functionaries, to the -clergy, and others, with directions to make it generally known. In -this way hundreds of thousands of copies of the ‘Instruction sur -les paratonnerres’ found their way all over France, and from thence -in translations all over Europe, as the best existing guide for the -erection of lightning conductors. - -The information thus spread by the French Government gave rise to -important results. It caused the setting-up of lightning conductors -throughout the country, on private as well as public buildings, and -it likewise led to an improved construction of them, in as far as the -‘Instruction’ recommended the rods to be made of stout pieces of metal, -well fastened to each other, and, above all, led into the ground deep -enough to reach moist earth or water. If this was well enough, and -useful enough, to meet with general acceptation, there were some points -in the advice of the learned men of the ‘Académie’ that gave rise -to much criticism, as being more founded upon theory than practical -experience. In the first place, they laid it down as a hard-and-fast -rule that the upper rod of a lightning conductor--that projecting over -the roof--‘will be an efficient protective against lightning within -the circular area of a radius double that of its height,’[1] and the -acquiescence in this supposed absolute formula had for one of its -results the erection of monstrously huge rods, made to tower high above -buildings, so as to increase the field of protection to the largest -possible extent. Another and worse fault was committed by the authors -of the ‘Instruction’ in not saying anything about the necessity of -regularly inspecting the actual condition of lightning conductors, and -testing them in respect to their efficiency. While giving minute advice -as to the mode of construction and the general design of conductors, -the contents of the ‘Instruction’ were such that, on the whole, its -readers would take it for granted that it was only necessary to -properly join the strips of metals and bring them down into the ground, -after which, thenceforth and for ever, the protection against lightning -would be complete. This grave omission, together with the erroneous -dogma as to absolute rule of protection within an area prescribed by -the height of the ‘tige,’ or upper part of the rod, had the inevitable -result of causing disasters, and before the ‘Instruction’ had been -issued many years, there came report after report to the - - [1] The original, long taken as a scientific dogma, runs: ‘Une - tige de paratonnerre protège efficacement contre la foudre - autour d’elle un espace circulaire d’un rayon double de sa - hauteur.’ - -Government that well-constructed lightning conductors had failed to -do their duty. For a length of time these reports were either not -believed in, or the failure ascribed to partial non-compliance with -the strict rules laid down by the ‘Académie des Sciences.’ However, in -the end, when thirty years had passed, the instances of buildings with -conductors being struck became so numerous, that it was impossible to -ignore them any longer and, flying once more for advice to the savants -of the ‘Académie des Sciences,’ the French Government desired them -to investigate anew the question as to the best means of protecting -buildings against lightning. Complying with the behest, the learned -body nominated again a committee of six, the names of those selected -comprising the most eminent men who had made electricity and its -phenomena their study. They were MM. Becquerel, Babinet, Duhamel, -Despretz, Cagnard de Latour, and Pouillet. - -The ‘Instruction’ of the new committee, drawn up by Professor Pouillet, -was read before the ‘Académie des Sciences’ on December 18, 1854, and -having been unanimously approved, was, like the former one, taken up by -the Government and extensively circulated. The report began by modestly -excusing the short-coming of its predecessor. ‘For the last thirty -years,’ Professor Pouillet remarked, with no fear of being gainsaid, -‘the science of electricity has made great progress--in 1823 the -discovery of electro-magnetism had only just been made, and none could -foresee the immense results that would spring from its revelations.’ -Based upon these grounds, the new ‘Instruction’ entirely reversed -many of the conclusions of the old one. First of all, it declared -inadmissible the theory of a fixed area of protection, to be calculated -by the length of the upper rod. ‘Such a rule,’ Professor Pouillet -justly remarked, ‘cannot be laid down with any pretence to accuracy, -since the extent of the area of protection is dependent from a mass of -circumstances--such as, among others, the shape of the building and the -materials entering into its construction. It is clear, for example, -that the radius within which the conductor gives protection cannot be -so great for an edifice the roof or upper part of which contains large -quantities of metals, as for one which has nothing but bricks, wood, or -tiles.’ Professor Pouillet then proceeded to give detailed instructions -in respect to the design and mode of manufacturing lightning -conductors. He insisted that the rods should be of greater capacity -than those recommended by Gay-Lussac in the report of 1823, and that -there should be as few joints as possible from the point to the earth. -He considered it of the greatest importance that all the joints should -be carefully tin soldered, otherwise the metallic continuity of the -conductor could not be assured. He also advised that the top of the -air-terminal should not taper to so fine a point as formerly, but -be rather blunt. A lightning conductor, said Professor Pouillet, is -destined to act in two ways. In the first place, it offers a peaceful -means of communication between the earth and the clouds, and by virtue -of the power of points the terrestrial electricity is led gently up -into the sky to combine with its opposite. In the second it acts as -a path by which a disruptive discharge may find its way to the earth -freely. In the latter case he considered there was a risk of a sharply -tapered point becoming fused, and recommended that the angle of the -cone at the top of the air-terminal should be enlarged. He also advised -that the point should be made of red copper instead of platinum, and -based his argument on the fact of copper being a better conductor of -electricity than platinum, and considerably cheaper. A copper point, -remarks M. Pouillet, subjected to a heavy stroke of lightning, would -be much less heated than a platinum point, and would scarcely in any -case be fused. While in the report of 1823, iron ropes were recommended -almost exclusively as the best material for conductors for ships, the -‘Instruction’ of 1854 declared strongly in favour of copper as the far -superior metal for the purpose. ‘Copper,’ affirmed Professor Pouillet, -‘is superior to iron as well as to brass for the purpose of lightning -conductors, it having the advantage not only of being less influenced -by atmospheric agencies, but the still more important one of allowing -a freer passage to the electric force of over three to one. Copper -should therefore be exclusively used in the construction of lightning -conductor cables for the protection of ships. - -The inquiries into lightning protection instituted by the ‘Académie -des Sciences,’ and resulting in two reports, the second valuable in -the highest degree, had the good effect, not only of drawing public -attention to the necessity of providing such safeguards, but of -bringing the whole matter under due scientific control. Henceforth the -ground was cut away under ‘lightning-rod men,’ perambulating towns -and villages, and offering their trumpery ware--mostly bits of wire -tied together, with perhaps a lacquered piece of wood on the top--to -credulous persons, as a substitute for good conductors. The French -Government set a laudable example in appealing for the future always to -scientific aid. A few months after the publication of the ‘Instruction -sur les paratonnerres,’ drawn up by Professor Pouillet, a decision was -come to for protecting the new wings of the Louvre, at Paris, with the -most perfect lightning conductor that could be made, and thereupon -appeal for counsel was once more made to the ‘Académie des Sciences.’ -The case was one of special interest. The palace of the Louvre, with -its inestimable treasures of art, had been the first public building -in France provided with a lightning conductor. It was due to the -initiative of an enthusiastic admirer of Benjamin Franklin, David Le -Roy, that this was accomplished, he having excited the public feeling -as to the dangers from lightning to which the Louvre was exposed to -such a degree as to compel the Government, in 1782, to carry out his -plans, under his own superintendence. The conductors erected by Le -Roy had stood the test of experience from 1782 until the year 1854, -many a thunderstorm having passed over the extensive buildings of the -Louvre without causing the least damage. But, in the last month of -1854, one more lightning cloud swept along the banks of the river -Seine, and the electric fire, falling on one of the chimneys of the -palace, knocked off a few bricks. The damage was very trifling, but -the alarm nevertheless was great, and very naturally so. If there was -one building in France, it was said, which ought to be beyond the risk -of being struck by lightning, it was the Louvre, and, if this could -not be accomplished, the art of constructing protective conductors was -altogether vain and ineffectual. It was under these circumstances, -incited by the public outcry, that the Government hastened to submit -the new case to the ‘Académie des Sciences.’ - -Once more the ‘Académie’ nominated a committee on lightning conductors, -composed of the same members who had signed the ‘Instruction’ of 1854, -and drawn up by Professor Pouillet. He again drew up the report, which -was adopted by the ‘Académie’ on February 19, 1855, and contained some -notable additions to the directions previously given. They related, -as was desired, in the first instance to the Louvre alone, but were -made applicable to all large public buildings. For their efficient -protection, the professor insisted, two things should be kept in view -above all others--namely, first, that the point, always of copper, -should be of greater thickness; and, secondly, that it should have a -never-failing connection with either water or very moist earth. To -ensure the latter, it was recommended, as had been done before, that -the underground part of the conductor should be divided. - -The necessity for such a division, and for forming at least two -subterranean arms--the first of it, described as ‘the principal -branch,’ going very deep into ground, into perennial water, and the -second, ‘the secondary branch,’ running nearer the surface--was -explained by Professor Pouillet very clearly in this last report. -‘After a long continuance of dry weather,’ he observed, ‘it often -happens that the lightning-bearing clouds exert their influence only -in a very feeble manner on a dry soil, which is a bad conductor; the -whole energy of their action is reserved for the mass of water which -by percolation has formed below it. It is here that the dispersion of -the electric force (_la décomposition électrique_) takes place; it -will follow the principal branch of the conductor underground, and -leave the secondary branch untouched. The case is entirely different -when, instead of dry weather, there have been heavy rains, moistening -the earth thoroughly, up to the surface. It is the latter now that -is the best, because the nearest, conductor of the electric force, -which will not go to the more permanent sheet of water, lying more or -less deep in the ground, if there is moisture above it. Under these -circumstances, it is indispensable that there should be a direct -connection between the surface soil and the lightning conductor, and -this is what is accomplished by the secondary branch. It is a power in -aid of the principal branch, and one often of the highest importance.’ -The suggestion here made was one so evidently good, that it was at -once accepted by the French Government, and the Louvre not only, but -other public buildings, received lightning conductors ending in two -subterranean branches, as proposed by Professor Pouillet. - -The report on the protection of the Louvre Palace did not contain -the last inquiry of the ‘Académie des Sciences’ on the subject of -lightning conductors. Twelve years after it had been issued, the -Government of France once again called upon that learned body for -advice as to the best mode of protecting powder magazines. Several -cases had happened--among others at Rocroy, on the borders of the -forest of Ardennes--of such buildings being struck, notwithstanding -that they had conductors placed upon them, and the Government, -naturally alarmed, made inquiry as to whether nothing could be done to -ensure protection against lightning, infallible under all atmospheric -conditions and every possible emergency, to these dangerous stores. The -demand was made in a letter of the Minister of War, Marshal Vaillant, -dated October 27, 1866, pressing the ‘Académie’ to give another -‘Instruction,’ without delay, the Government being ‘in fear that some -of the powder magazines are not as completely protected from lightning -as could be wished.’ Thereupon the ‘Académie des Sciences’ nominated -another commission, this time of eight members, including the Minister -of War himself--not complimentary, but as being an author, and with a -warm interest in electrical science; and, besides him, MM. Becquerel -Sen., Babinet, Duhamel, Fizeau, Edmond Becquerel, Regnault, and -Professor Pouillet. The list represented a galaxy of names unsurpassed -in the investigation of such a subject as lightning conductors, looked -upon in most countries of Europe, at least in recent years, as rather -plebeian, to be left to builders and lightning rod men. Many sittings -were held by the committee, all fully attended, so that, although -the Minister had desired to get the new report ‘_le plus promptement -possible_,’ it was not till nearly three months after the receipt of -his message that it was completed, Professor Pouillet again being the -author. It was a most remarkable paper, this one, read before and -approved of by the ‘Académie des Sciences’ on January 14, 1867. - -Before entering upon the subject of the protection of powder magazines -against lightning, the new ‘Instruction’ signed by Professor -Pouillet and his colleagues laid down a few so-called ‘_propositions -générales_‘--that is, either hints, suggestions, or statements, -the French word ‘_proposition_’ being most serviceably vague for -use--on the subject of lightning and of thunderstorms. The first -thesis affirmed that ‘clouds which carry lightning with them are but -ordinary clouds (_ne sont autre chose que des nuages ordinaires_) -charged with a large quantity of electricity.’ The second thesis -boldly defined the nature of lightning. ‘The fire which flashes -from the skies is an immense electric spark, passing either from -one cloud to another, or from a cloud to the earth; it is caused -by a tendency for the restoration of the electric equilibrium (_la -recomposition des électricités contraires_).’ It was laid down in the -third ‘_proposition_’ that, when lightning falls from a cloud upon the -earth, it is but an effort of the electric force to return to its -grand reservoir. That it is similar to water, which, having risen in -the form of vapour from the earth-surrounding ocean high up into the -air, then falls down as rain upon hills and plains, and finally runs -down again in rivers to the ocean, Professor Pouillet did not say in -so many words; but there were vague hints to that effect in the new -‘Instruction.’ Its practical recommendation, offspring of the theories -thus enunciated, was that the best protection against lightning -would be afforded by the most substantial metal rods, made of iron, -surrounding a building on all sides, and passing deep into the ground. -The new declaration of the ‘Académie des Sciences,’ though merely a -repetition of former reports, was not without important consequences. -First in France, and then in other countries, the conviction became -general among scientific men, and others well informed on the subject, -that well-designed conductors, if properly made and kept in good order, -form an absolute, unconditional, and infallible protection against -lightning. - -Professor Pouillet also laid it down that lightning conductors, to be -efficient, must be regularly inspected, he, with his colleagues on the -committee, having come to the conclusion that such examination should -take place at least once every year. So much stress was laid upon the -importance of an annual inspection, that a strong recommendation was -made to the Government to have a _procès-verbal_, or special report, -drawn up on each occasion in the case of all public buildings, so that -it might be known by the central authorities whether the examination -had taken place at the specified time, and what had been the -declaration of the examiners. The advice was judiciously followed, with -the result that at this moment the public buildings of France have the -most complete protection against lightning--greatly in contrast with -the public buildings in England. - - - - -CHAPTER VIII. - -SIR WILLIAM SNOW HARRIS. - - -In singular contrast with what took place in France, the importance of -lightning conductors never created any but the most languid interest -in England. Neither the Government, nor any of the scientific bodies -of the country, at any time occupied themselves seriously with the -question as to how public and private buildings might be best protected -against the dangers of thunderstorms; and from the time, a century ago, -when the Royal Society half patronised and half spurned the merits -of Franklin’s discovery, to this day, the battle of science against -ignorance in the matter had to be fought by individuals. With one -exception, that of Sir William Snow Harris, it proved no profitable -battle to any man; and in his case even, it was only so by accident. -Born at Plymouth, in 1792, and educated for the medical profession, -he early turned his attention to the subject of electricity and -lightning conductors, and more particularly to the use of them in the -Royal Navy. Owing to his early surroundings, leading to connection -with naval officers, he learnt that the damages caused by lightning -to ships of war were very numerous, and most expensive to repair; and -having got once hold of these facts, he gave them to the public in -the ‘Nautical Magazine,’ but chiefly in pamphlet form, insisting upon -the simple remedy of lightning conductors. As usual, the Government -lent a deaf ear to the proposal as long as it was possible, and it -was only when at length, in 1839, the outcry upon the subject became -overwhelming, that a naval commission was appointed ‘to investigate the -best method of applying lightning conductors to Her Majesty ships.’ -The commission drew up an immense report, filling eighty folio pages -of a blue-book, the kernel of which was that, though such protectors -in thunderstorms were rather new-fangled things, they might be tried -without special harm coming to anybody. Thereupon most of the vessels -received lightning conductors, made after designs by Mr. Snow Harris. -The indefatigable advocate of conductors had his reward. He was -knighted in 1847; he had, at various times, considerable grants from -the Government; and he had the final satisfaction of being allowed -to design lightning conductors for the new Houses of Parliament. The -latter remain the most enduring monument of the only man in this -country who ever succeeded in drawing the attention of the public -and the Government to the grave subject of lightning conductors. He -could not have done so, at least not in the line he took up, had he -lived half a century later. With the gradual disappearance of the old -wooden ships disappeared also the necessity of lightning conductors -for men-of-war. An iron-built vessel, metal-rigged, is a conductor by -itself, while as to armour-clad ships of latest design, they are more -absolutely protected against lightning even than the famous gilded -temple of Solomon at Jerusalem. - -In the story of the progress of lightning protection in England, the -career of William Snow Harris forms a chapter of no little interest, -as showing both the inertness of the administration, as well as of -the public, in the most important matters, and the good effects that -may result from the persevering energy of a single man. When Mr. -Snow Harris began his agitation for lightning conductors, about the -year 1820, the ships of the Royal Navy were virtually without them, -although they had something supposed to stand in their place. Just -sixty years before, in 1762, Dr. William Watson, the indefatigable -advocate of Franklin’s discovery, had strongly recommended to Lord -Anson, first Lord of the Admiralty, that all men-of-war should have -lightning conductors; and his urgent zeal, backed by influential -friends, effected that his advice was listened to. Being requested to -send in the best design for a ship’s conductor, Dr. Watson did so with -alacrity, but, unfortunately, with little wisdom. Knowing little or -nothing of ships and their management at sea, the learned member of -the Royal Society advised that the lightning conductors for the navy -should be constructed of strips of copper rod, one-fourth of an inch -in diameter, hooked together every few feet by links, and the whole -attached, for more security, to a hempen line, to be hung on to a -metal spike on the top of the mast, and from thence to fall down into -the sea. In theory, it was not a bad design, but it utterly failed in -practice. Evidently, Dr. Watson had never been on board of a large ship -in a gale, for had he been, he might have known that it would be next -to impossible to keep his chain in its place, exposed as it was to the -operation of violent mechanical forces, not to speak of possible bad -treatment from indignant sailors, with whose movement in the rigging -it interfered. It was a natural consequence of Dr. Watson’s ignorance, -that his conductors entirely failed. In most cases the commanders of -men-of-war, supplied with the copper-hempen chains, quietly stowed them -away in some corner of the ship, with orders to take them out when -needed, and it often happened that this was done only after the ship -had been struck by lightning. Year after year there came reports of -such casualties; and at last they got so numerous as really to attract -the attention of the naval authorities. Still, nothing was done until -William Snow Harris took up the matter. Sitting in his little cottage -at Plymouth, overlooking the sea, the happy thought struck the young -medical man, waiting for patients who did not come, that here might -be found a profitable as well as useful opening for his activity. -He possessed, happily, a few naval friends, ready with counsel and -assistance, and so he went to action, fighting for lightning conductors. - -The battle, resulting as it did in ultimate victory, was a long one, -nevertheless. For many years, all his efforts to induce the British -Government to adopt a system of efficient lightning conductors for the -Royal Navy remained entirely fruitless; and it was only after he had -gained the sympathy of the press, and, through it, of the public, by -publishing long lists of the disasters that had befallen the cherished -‘wooden walls of England,’ that at last the closed doors of the -Admiralty were opened to him. The lists he furnished were appalling -indeed, and enough to impress any minds and open any doors. It was -shown by Mr. Snow Harris, from carefully compiled records, based upon -official documents, that in the course of forty years--from 1793 to -1832--over 250 ships had suffered from lightning. In 150 cases, the -majority of which occurred between the years 1799 and 1815, about 100 -main-masts of line-of-battle ships and frigates, with a still larger -number of topmasts and smaller spars, together with an immense quantity -of stores, were destroyed by lightning. One ship in eight was set on -fire in some part of the rigging or sails, and over 200 seamen were -either killed or severely disabled. But, formidable as was this account -of damage done by lightning, it by no means completed the list of -casualties. Mr. Snow Harris gave it as his opinion, on the authority of -a great many naval officers with whom he came into contact at Plymouth, -that many ships reported officially as ‘missing’ had been struck by -lightning and gone to the bottom, with nobody left behind to tell the -tale. Thus, from a reference to the log of the line-of-battle ship -the ‘Lacedæmonian,’ under the command of Admiral Jackson, it appeared -that this man-of-war sailed alongside a frigate, the ‘Peacock,’ on the -coast of Georgia, in the summer of 1814, and that the latter suddenly -disappeared in a storm of lightning, leaving no trace behind. Again, -the ‘Loup Cervier,’ another man-of-war, was last seen off Charlestown, -in America, on the evening of a severe thunderstorm, and never heard -of again. A famous ship, the ‘Resistance,’ of forty-four guns, was -struck by lightning in the Straits of Malacca, and the powder-magazine -blowing up, it went to the bottom, only three of the crew reaching the -shore, picked up by a passing Malay boat. But for these few survivors, -Mr. Snow Harris justly remarked, nothing would have been known of -the fate of the vessel, which would have been simply reported as -‘missing’ in the Admiralty lists. It was scarcely to be wondered at -that the recital of all these tales of disasters, which might have been -prevented by the most ordinary foresight in applying known means of -protection against lightning, considerably excited the public mind, so -that at last the Government was compelled to act in the direction into -which it was impelled by the energetic Plymouth doctor. It was thus -that at last, in 1839, the naval commission already referred to was -appointed to give counsel as to ‘applying lightning conductors to Her -Majesty’s ships.’ - -Perhaps even this step in advance might not have favoured much the -cause pleaded by Mr. Snow Harris, had he not had the good fortune of -finding a powerful patron in Sir George Cockburn, one of the Lords -of the Admiralty. Sir George, born in London, of Scottish parents, -in 1772, had all his life long taken a great interest in scientific -pursuits; and the application of conductors especially had interested -him much, as he had himself been a witness to frequent damage done -to ships under his command by lightning. The ‘Minerva,’ of which he -was captain at the blockade of Leghorn, in 1796, had been so struck, -and likewise two ships of the flotilla, reducing the French island of -Martinique, in 1809, under his direction. Having taken a prominent part -in the American War of 1813–14, especially the capture of Washington, -Sir George Cockburn retired from active service, and in 1818 was made -one of the Lords Commissioners of the Admiralty, immediately after -being returned a Member of Parliament for Portsmouth. He henceforth -devoted himself more than ever to scientific studies; and, having been -elected a Fellow of the Royal Society, got into acquaintance with many -of its members, among them with Mr. Snow Harris, whom he came to like -on account of his fervid enthusiasm in the cause he was advocating. -The acquaintance proved of the highest advantage to the young Plymouth -electrician. Before even the naval commission, nominated to give -counsel upon the subject of lightning conductors, had given in its -report, he was allowed to make trial, on board of several men-of-war, -with a system designed by himself, and for which he had taken out a -patent. It was not long afterwards that it was officially adopted for -all the vessels of the Royal Navy, with, it is needless to say, the -greatest pecuniary advantages to the designer. - -The system of Mr. Snow Harris for protecting ships against lightning -was similar to that suggested by Mr. Henly in 1774. Instead of hanging -dangling chains from the top of the rigging into the water, he nailed -on to the masts and down to the keel, slightly inlaid in the wood, a -double set of copper plates, overlying each other in such a manner that -the ends of one set were touched by the middle of the other. The plates -were four feet in length, two to five inches wide, and one-eighth of -an inch thick; they had holes drilled in them at distances of six -inches apart, and were secured to the masts and further down by short -copper nails. In order to prevent any break in the conductor at the -junction of the successive masts, a copper plate was led over the cap, -and the continuity preserved at all times by means of a copper hinge -or tumbler which fell against the conductor. It was an altogether -unobjectionable plan for securing protection against lightning, except -that it was liable to fail under imperfect execution. Bad workmanship -necessarily was fatal to it. The numerous copper plates had to be very -neatly and carefully fastened together to ensure metallic continuity, -in the absence of which the electric force might leave the path traced -for it, diverging into neighbouring metallic masses, numerous on board -ships, such as chains and anchors. It was a most costly system from -beginning to end; but as it was, and, for the short time it remained -in use, it accomplished all that was desired. Not one of the ships -fitted with the conductors designed by Mr. Snow Harris was damaged by -lightning, although many were struck, the electric spark in several -cases being so powerful as to melt the too fine metal points on the -top of the masts. However, the new lightning conductors had not to -stand the ordeal of practice for any length of time. One by one the -great wooden ships of war, once the pride and glory of England, went -into peaceful retirement, to be replaced by iron machines, propelled -by steam, metalled from the top of the masts to the water’s edge. It -had been one of the recommendations of Mr. Snow Harris to the Admiralty -that his copper plates, though expensive at first, would always be -worth their money as old metal; and the irony of fate would have -it that the conversion of copper into silver was not to be long in -waiting. Before the death of the inventor, which occurred in January -1867, his lightning conductors were fast disappearing from the ships -on which they were placed. From the windows of his villa at Plymouth, -Sir William Snow Harris could see a fleet of ironclads, dispensing with -conductors, floating on the sea. - -Notwithstanding the short use of his own special naval work which gave -him fame, Sir William Snow Harris effected much in the interest of -lightning protection in general. He was one of the few men in England -who insisted that it was the duty of the Government, as well as of -private individuals, to place lightning conductors upon all objects -liable to be struck, arguing that it was little less than criminal -to neglect such a simple protection against overwhelming danger. It -was with some degree of vehemence, though not more perhaps than was -requisite, that he stood out against those who objected to conductors -because they ‘attracted’ lightning. Such assertion will, at the present -day, be regarded as foolish by all persons possessed of the least -scientific knowledge; but this was not by any means the case forty or -fifty years ago, when even well-educated men denounced conductors. -A civil engineer in the service of the British Government, Mr. F. -McTaggart, sent to Canada in 1826, recommended openly the pulling-down -of all lightning conductors in that colony, and this too in the name -of ‘science,’ of which he held himself to be an enlightened disciple. -‘Science,’ wrote Mr. McTaggart, in a book he published,[2] ‘has every -cause to dread the thunder-rods of Franklin; they attract destruction, -and houses are safer without than with them. Were they able to carry -off the fluid they have the means of attracting, then there could be no -danger; but this they are by no means able to do.’ Had such reasonings -as these been merely the senseless talk of a few individuals, the harm -done might not have been great. But it was quite otherwise. Men of -power and position, if not of high education, were imbued profoundly -with the same ideas as Mr. McTaggart, as evidenced in at least one -striking instance, which would be scarcely credible were it not on -official record. In the year 1838, the Governor-General and Council of -the East India Company actually ordered that all the lightning rods -should be removed from their public buildings, including the arsenals -and powder magazines, throughout India. The rulers of the great country -had come to their decision, as they stated, by the advice of their -‘scientific officers,’ who all apparently shared Mr. McTaggart’s belief -of the perils of ‘the thunder rods of Franklin.’ It was partly on the -representation of the energetic vindicator of lightning conductors -in Plymouth, that the order for their destruction in India was soon -countermanded by the authorities in Leadenhall Street, but not before -several buildings had been destroyed, among them a large magazine at -Dumdum, and a corning-house at Magazine. As often before, so now, -lightning itself proved the most powerful advocate of conductors, and -in India they were more quickly set up than they had been thrown down. - - [2] _Three Years in Canada._ 8vo. London, 1829. - -While designing lightning conductors for the ships of the Royal Navy, -Mr. William Snow Harris was called upon likewise by the Secretary of -State for War to give advice as to the best protection that might -be given to powder magazines and other stores of war material. He -did as requested, writing a very lucid paper on the subject, which -met with the honour, unique in its way, of being put forward as an -official document. To this day there is regularly issued with the -‘Army Circulars’ from the War Office a series of ‘Instructions as -to the Applications of Lightning Conductors for the Protection of -Powder Magazines, &c.,’ reproducing textually the recommendations -of Mr. Snow Harris. These ‘Instructions,’ containing the essence of -what he wrote about conductors, and, in fact, the result of all his -investigations on the subject, treat the whole _ab ovo_, and as such -deserve quotation. ‘Thunder and lightning,’ Mr. Snow Harris wrote to -the War Office, ‘result from the operation of a peculiar natural agency -through an interval of the atmosphere contained between the surface -of a certain area of clouds, and a corresponding area of the earth’s -surface directly opposed to the clouds. It is always to be remembered -that the earth’s surface and the clouds are the terminating planes of -the action, and that buildings are only assailed by lightning because -they are points, as it were in, or form part of, the earth’s surface, -in which the whole action below finally vanishes. Hence, buildings, -under any circumstances, will be always open to strokes of lightning, -and no human power can prevent it, whether having conductors or not, or -whether having metals about them or not, as experience shows.’ - -Mr. Snow Harris then went on philosophising. ‘Whenever,’ he said, ‘the -peculiar agency--whatever it be--active in this operation of nature, -and characterised by the general term electricity or electric fluid, -is confined to substances which are found to resist its progress, -such, for example, as air, glass, resinous bodies, dry wood, stones, -&c., then an explosive form of action is the result, attended by such -an evolution of light and heat, and by such an enormous expansive -force, that the most compact and massive bodies are rent in pieces, -and inflammable matter ignited. Nothing appears to stand against it: -granite rocks are split open, oak and other trees of enormous size rent -in shivers, and masonry of every kind frequently laid in ruins. The -lower masts of ships of the line, 3 feet in diameter and 110 feet long, -bound with hoops of iron half an inch thick and five inches wide, the -whole weighing about 18 tons, have been in many instances torn asunder, -and the hoops of iron burst open and scattered on the decks. It is, in -fact, this terrible expansive power which we have to dread in cases of -buildings struck by lightning, rather than the actual heat attendant on -the discharge itself.’ - -He continued: ‘When, however, the electrical agency is confined to -bodies, such as the metals, and which are found to oppose but small -resistance to its progress, then this violent expansive or disruptive -action is either greatly reduced or avoided altogether; the explosive -form of action we term lightning vanishes, and becomes, as it were, -transformed into a sort of continuous current action of a comparatively -quiescent kind, which, if the metallic substance it traverses be of -certain _known_ dimensions, will not be productive of any damage to -the metal; if, however, it be of small capacity--as in the case of a -small wire--it may become heated and fused; in this case the electrical -agency, as before, is so resisted in its course as to admit of its -taking on a greater or less degree of explosive and heating effect, -as in the former case. It is to be here observed, that all kinds of -matter oppose some resistance to the progress of what is termed the -electrical discharge, but the resistance through capacious metallic -bodies is comparatively so small as to admit of being neglected under -ordinary circumstances; hence it is, that such bodies have been termed -conductors of electricity, whilst bodies such as air, glass, &c., -which are found to oppose very considerable resistance to electrical -action, are placed at the opposite extremity of the scale, and termed -non-conductors or insulators. The resistance of a metallic copper wire -to an ordinary electrical discharge from a battery was found so small, -that the shock traversed the wire at the rate of 576,000 miles in a -second. The resistance, however, through a metallic line of conduction, -small as it be, increases with the length, and diminishes with the area -of the section of the conductor, or as the quantity of metal increases.’ - -After these theoretical explanations, Mr. Snow Harris went into the -practical part of the business of protecting buildings, and, more -especially, powder magazines and others containing explosive materials, -against the effects of lightning. ‘It follows,’ he remarked,’from these -established facts, that if a building were metallic in all its parts, -an iron magazine for example, then no damage could possibly arise to -it from any stroke of lightning which has come within the experience -of mankind. A man in armour is safe from damage by lightning. In fact, -from the instant the electrical discharge, in breaking with disruptive -and explosive violence through the resisting air, seizes upon the mass -in any point of it, from that instant the explosive action vanishes, -and the forces in operation are neutralised upon the terminating planes -of action--viz., the surface of the earth and opposed clouds. All this -plainly teaches us that, in order to guard a building effectually -against damage by lightning, we must endeavour to bring the general -structure, as nearly as may be, into that passive or non-resisting -state it would assume, supposing the whole were a mass of metal. To -this end, one or more conducting channels of copper, depending upon the -magnitude and extent of the building, should be systematically applied -to the walls. These conducting channels should consist either of double -copper plates, united in series one over the other, as in the method of -fixing such conductors to the masts of her Majesty’s ships, the plates -being not less than 3½ inches wide, and of 1/16th and ⅛th of an inch -in thickness; or the conductors may with advantage be constructed of -stout copper pipe, not less than 1/16th of an inch thick, and 1½ to 2 -inches in diameter; in either case the conductors should be securely -fixed to the walls of the building, either by braces, or copper nails, -or clamps. They should terminate in solid metal rods above, projecting -freely into the air, at a moderate and convenient height above the -point to which they are fixed, and below they should terminate in one -or two branches leading outward about a foot under the surface of the -earth; if possible, they should be connected with a spring of water or -other moist ground. It would be proper, in certain dry situations, to -lead out, in several directions under the ground, old iron or other -metallic chains, so as to expose a large extent of metallic contact in -the surface of the earth.’ - -A few pregnant sentences, which by themselves deserved the honour of -permanently figuring in the ‘Instructions’ sent out by the War Office, -completed the advice given by Mr. William Snow Harris in respect to the -setting up of lightning conductors. ‘A building,’ he truly remarked, -‘may be struck and damaged by lightning without having a particle of -metal in its construction. If there be metals in it, however, and they -happen to be in such situations as will enable them to facilitate the -progress of the electrical discharge, so far as they go, then the -discharge will fall on them in preference to bodies offering more -resistance, but not otherwise. If metallic substances be not present, -or, if present, they happen to occupy places in which they cannot be of -any use in helping on the discharge in the course it wants to go, then -the electricity seizes upon other bodies, which lie in that course, -or which can help it, however small their power of doing so, and in -this attempt such bodies are commonly, but not always, shattered in -pieces.’ He summed up as follows:—‘The great law of the discharge is, -progress between the terminating planes of action--viz., the clouds -and earth--and in such line or lines as, upon the whole, offer the -least mechanical impediment or resistance to this operation, just as -water, falling over the side of a hill in a rain storm, picks out, or -selects as it were by the force of gravity, all the little furrows -or channels which lie convenient to its course, and avoids those -which do not. If in the case of lightning you provide, through the -instrumentality of efficient conductors, a free and uninterrupted -course for the electrical discharge, then it will follow that course -without damage to the general structure; if you do not, then this -irresistible agency will find a course for itself through the edifice -in some line or lines of least resistance to it, and will shake all -imperfect conducting matter in pieces in doing so. Moreover, it is to -be especially remarked in this case, that the damage ensues, not where -the metals are, but where they ceased to be continued; the more metal -in a building, therefore, the better, more especially when connected -by an uninterrupted circuit with any medium of communication with the -earth.’ - -‘Such is, in fact,’ he concluded, ‘the great condition to be satisfied -in the application of lightning conductors, which is virtually nothing -more than the perfecting a line or lines of small resistance in -given directions, less than the resistance in any other lines in the -building, which can be assigned in any other direction, and in which, -by a law of nature, the electrical agency will move in preference to -any others. The popular objections to lightning conductors on the -ground that they invite lightning to the building, that we do not know -the quantity of electricity in the clouds, and that hence they may -cause destruction, are now quite untenable, and have only arisen out of -a want of knowledge of the nature of electrical action. What should we -think of a person objecting to the use of gutters and rain-pipes for a -house, on the ground of their attracting or inviting a flow of water -upon the building; and since we do not know the amount of rain in the -clouds, it is possible that the building may be thereby inundated,--yet -such is virtually the argument against lightning conductors.’ - -Mr. Snow Harris, as already mentioned, received the honour of -knighthood in 1847; and after this date lived in comparative retirement -for twenty years at his residence, Windsor Villas, Plymouth. However, -he was called upon, in 1855, to undertake one more important work in -designing a perfect system of lightning conductors for the new Houses -of Parliament at Westminster. It was on the initiative of Sir Charles -Barry, the architect, that the proposal was made by the Board of Works -to Sir William Snow Harris, who accepted it with all his old eagerness -for serving the cause of lightning protection. Accordingly, he drew up -a plan, which he himself characterised, in a letter to the President -of the Board of Works, dated February 14, 1855, as ‘somewhat costly,’ -but which he felt sure would be absolutely certain ‘for insuring the -safety of the buildings against one of the most terribly destructive -elements of nature.’ In its essence, the plan consisted in protecting -all the most elevated parts of the Houses of Parliament, including the -towers, by ‘a capacious metallic conductor of copper tube, two inches -in diameter, and not less than one-eighth of an inch in thickness,’ to -be fastened together ‘by solid screw plugs and coupling pieces,’ and -‘secured to the masonry by efficient metallic staples.’ To do this, -Sir William Snow Harris calculated, would involve an expenditure of -somewhat over 2,000_l._, but nothing less would accomplish it. ‘What -I have recommended,’ he wound up his letter, ‘has been the result of -very serious and attentive deliberation, and I conscientiously think -that what I have proposed is absolutely requisite to a permanent -and satisfactory security of the buildings against the destructive -agency of lightning.’ The Board of Works entirely adopted all the -recommendations of Sir William Snow Harris, and, in accordance with -them, there was included in the Civil Service Estimates laid before the -House of Commons in the session of 1855 a vote of 2,314_l._, on account -of ‘works necessary for securing the new Houses of Parliament against -danger from lightning.’ - -The vote passed without demur. It was in the height of the Crimean War -fever, political questions absorbing all others. Perhaps in a time -of less excitement some voice might have been raised in the House of -Commons asking whether it was wise to spend over 2,000_l._ in putting -up lightning conductors, without previously ascertaining, from the -best scientific authorities, that the system adopted was the best, -and absolutely efficacious. The strongly recommended ‘copper tubes,’ -with their ‘screw plugs and coupling pieces,’ were at least a novelty, -not having stood the test of experience, and there were practical -men who shook their heads when they heard of them. However, with -war discussions raging fiercely, and reports of battles and sieges -absorbing all attention, the House of Commons had no time to bestow -upon such trifling matters as that involved in the plans of Sir William -Snow Harris; and thus the vote passed unchallenged. Perhaps silent -repentance came afterwards to the official mind. At any rate, as it was -the first, so it was the last time of Parliament granting money for -lightning conductors. - -[Illustration] - - - - -CHAPTER IX. - -THE BEST MATERIAL FOR CONDUCTORS. - - -‘The art of protection against lightning,’ says a recent German -writer, in a book on conductors, ‘is precisely the same now as it was -a hundred years ago: still, it has made immense progress since that -time.’ Though apparently involving a paradox, the words nevertheless -are literally true. The art, or rather science, of guarding objects -against the destructive effects of lightning is theoretically the same -as it was in the days of Benjamin Franklin; nevertheless, the practical -execution of the appliances necessary to attain this aim has undergone -extraordinary improvements since that time. This has been due simply to -the astounding progress of the metallurgical arts for the last forty or -fifty years. With the help of machinery on a colossal scale, such as -was never dreamt of before, our factories have come to produce metallic -masses of dimensions and shapes such as make all former achievements of -the kind appear utterly insignificant. We build huge iron ships, armed -with cannon of ponderous weight; we throw iron bridges across rivers -and arms of the sea; we lay metallic cables through the ocean and over -the earth, encircling the globe. All these wonderful achievements, in -which the development of engineering science went hand in hand with -that of tool-making and the ever-growing employment of the power of -steam, have gone to the constant improvement of lightning conductors. -They have benefited, indirectly, in the result of great inventions, and -of immense toil and labour, originally directed to other ends. - -There is something half touching, half comical, in reading of the -troubles which Benjamin Franklin had to undergo before he was able to -set up his first lightning conductor. He could meet with no assistance -but that of the blacksmith of little Philadelphia; and the ability -of the latter in the art of forging iron rods more than a few feet -in length was of the most limited kind. The ingenuity of Franklin -overcame this difficulty by a variety of clever contrivances, such -as connecting a number of small rods by caps and joints, fitting -closely; but others were not so successful as he in the matter. Even -in Paris there were no artisans to be found, for many years after -lightning conductors were first recommended, able to make them, and -foreigners, chiefly English, had to be brought there for the purpose. -The difficulties arising from this backward state of the industrial -arts were greatly increased by the belief, prevalent for a long time, -that lightning conductors, to be efficient, ought to be of very great -height, their so-called ‘area of protection’ being in proportion to -their height. The supposition, originating in France, was carried to -extremes in that country, chiefly through the teachings of M. J. B. -Le Roy, a very able but eccentric man. Guided by vague analogies in -electrical phenomena, M. Le Roy, who enjoyed in his time--the latter -part of the eighteenth century--the reputation of being an authority on -the subject of lightning conductors, laid it down as an indisputable -fact that the ‘Franklin rods’ only protected buildings if rising high -above them. He recommended the length of the rods above the chimney, or -summit of any edifice, to be not less than fifteen feet, guaranteeing -that, if of this height, they would offer absolute protection against -lightning over an area of four times the same diameter--that is, sixty -feet. Modern experience has proved this to be an absurdity; still, -in the infancy of all knowledge about lightning conductors it was, -perhaps, not unnatural that even learned men should believe in such -fancies. Lightning was looked upon, not only in name but in reality, -as an electric ‘fluid’ and the conductor was supposed to draw this -‘fluid’ from the clouds. Therefore it was but cogent reasoning to raise -conductors as high above the roofs, and as near to the storm-clouds, as -could possibly be done. If possessed of modern means for manufacturing -pieces of metal of almost any length, M. Le Roy would not improbably -have recommended to elevate lightning conductors a couple of hundred -feet, instead of only fifteen, above the summit of buildings. - -It was owing chiefly to the difficulty of forging long iron pieces, -and of welding them together in a satisfactory manner, that, for many -years after lightning conductors had been introduced into Europe, -there were constant attempts made to find substitutes for the rods -devised by Franklin. Chains were largely used towards the end of the -last and the beginning of the present century, both in France and -Germany, their employment having been suggested by the example of the -English navy, where they were introduced, as already mentioned, upon -the recommendation of Dr. Watson. The Continental mode of using iron -chains for the protection of buildings against lightning was to hang -them between the upper part of the conductor, surmounting the roof, -which continued to be a straight piece of metal or rod, and the lower -portion buried in the ground, sometimes, but not always, likewise a -chain, but thicker than the rest. The characteristic of this method, -and showing its long existence, is that it gave rise to a nomenclature -existing to this day in France and Germany, where in all books on -lightning conductors they are described as consisting of three distinct -parts. The French call the upper part of the rod, over the roof, ‘_la -tige_,’ the stem or stalk; and the Germans, ‘_die Auffangstange_’ -literally the reception-rod. In both languages the middle part, -from the roof downwards to the earth’s surface, is described as the -conductor proper, ‘_le conducteur_’ and ‘_der Leiter_.’ Again, the -lowest underground part of the conductor is designated, by the French, -‘_la racine_,’ the root, and by the Germans as ‘_der Bodenleiter_,’ -or the ground-conductor. It has often been said that, as language -springs from ideas, so it reacts upon them, and if the proposition -be true, as most will admit, the French and German designations of -the parts of lightning conductors--also to be found in Italian, and -adopted in a few of the older English treatises on the subject, mostly -translations--have a strongly misleading tendency. Nothing could be -further from the truth than the assertion that a conductor ought to -consist of three distinct parts. On the contrary, the more it is ‘one -and undivided,’ the better it will be as a lightning protector. - -The use of iron chains as conductors gave rise to very many fatal -accidents, and for a time resulted in an outcry that the system -itself could not be depended upon, as it was known to be not always -efficacious. Lists were published of numerous instances in which -buildings with what were supposed to be the best conductors were struck -by lightning, from which it was argued that Franklin’s great discovery -of the electric force always seeking a metallic path to the earth -was a myth. It was not till some painstaking scientific men, deeply -interested in the subject, had set to work to discover the causes -of the failure, that the whole became plain enough. The chains, in -some of the instances in which they had proved inefficient lightning -conductors, were found to be corroded to such an extent as barely to -hang together. Of course this corrosion would impair the efficiency -of the conductor by reducing the quantity of metal; but the chief -objection to the use of chains lies in the fact long ago pointed out -by Mr. Newall, that even supposing a chain were formed of links of -half-inch copper rods, and were perfectly bright and clean, the area -of the conductor is reduced to a mere point where the links touch each -other, and the resistance becomes so great in such a small conductor -that instances have been recorded of the fusion of the links. In other -cases, as in that of H.M.S. ‘Ætna’ in 1830, the chain was boomed out, -and did not touch the water! - -Simultaneously with the chains, there was trial made, in several -Continental states, and also in England, of several other metallic -conductors besides iron. Tin and lead had both their advocates, but -the latter more than the former, on account of its far lower price. As -regards tin, it had really no advantages whatever over iron, except -pliability and non-oxidation. Against this was to be set that it was -much more expensive than iron, with only about the same conducting -power, according to Becquerel, Ohm, and other investigators. Professor -Lenz, it is true, ranked tin very much higher, asserting, from -experiments of his own, that its power of conductivity was nearly twice -that of iron; and it was partly owing to his great influence that -the metal obtained a trial in several countries, more particularly -in Russia and in the United States of America. Still, the result was -not satisfactory on many accounts, and its price alone brought tin -to be soon abandoned as a conductor. Lead had a far longer trial. -Its cheapness recommended it strongly, and equally so its extreme -pliability. One of the greatest difficulties of the constructors of -‘Franklin rods,’ when first they came into demand, was to make the -iron pieces fit properly around sharp corners of buildings, either -by bending them in fire, or, as was more commonly done, soldering -them together, or employing screws and other joints. But it was early -discovered that these junctions, when occurring at acute angles, were -bad conductors, occasioning sometimes the electric force to leave its -traced course, and fly off in some other direction. It is probable -that, in several well-authenticated instances in which this really did -happen, the joints were eaten away by oxidation, as in the case of -the chains; still, the effect of such occurrences was all the same. -The joining of strips of lead together was a far easier task than -that of handling iron in the same way, particularly for inexperienced -workmen, and thus the employment of the metal continued for some -time. However, it had to be abandoned gradually, on account of its -manifest disadvantages. Its extreme softness, which made it liable to -be broken by any accident, was one of them, and, still more so, its -want of conducting power--only about one-half that of iron. Thus leaden -conductors slowly went out of use, except in the form in which they -still act often to great advantage, that of water-pipes. - -Among all the experiments made for producing the most perfect lightning -conductors, the one which created the greatest attention, some fifty -years ago, both on the Continent and in England, was the employment -of ropes made of brass wire. They were first recommended about the -year 1815 by a professor at the University of Munich, J. C. von Yelin, -distinguished for his researches into the nature of thunderstorms. -Through his influence most of the public edifices of Bavaria, more -particularly the churches, were provided with conductors of brass -ropes; and within a few years their employment became so popular, -owing to the ease with which they could be attached to all buildings, -that even the Roman Catholic clergy changed their attitude, and, -from being opposed to ‘heretical rods,’ advocated their extension in -every direction. But it was not long before the trust in brass ropes -as protectors against lightning was rudely shaken. Several instances -occurred in which buildings so protected were struck and damaged by -lightning, and at last there came a case which attracted the widest -attention, leading, on account of its supposed importance, to the -institution of a Royal Commission to report thereon. The little town -of Rosstall, in Franconia, Bavaria, had a church the steeple of which -was 156 feet high; and, standing on the brow of a hill, it overlooked -the country far and wide, visible for many miles. Necessarily much -exposed to the influence of lightning clouds, it had been provided -with one of the best brass-wire conductors, designed by Professor von -Yelin himself, and made of unusual thickness, being over an inch in -diameter. Nevertheless, on the evening of April 30, 1822, while a dark -storm-cloud, of extraordinary thickness, was passing over Rosstall, a -heavy flash of lightning was seen to fall vertically upon the church -steeple, followed by a terrible peal of thunder, which seemed to shake -the earth. When people looked up they beheld the church clock thrown -from its place, and part of a lower wall of the edifice thrown to the -ground. It was clear that the electric discharge from the atmosphere -had been one of unusual energy, but equally clear that the trusted -conductor had not done its work. - -It was partly through scientific controversies about the relative -conducting value of metals, and partly through the action then -taken by several German Governments of providing all buildings with -lightning conductors, that the Rosstall case excited an extraordinary -interest at the time. The Royal Commission appointed by the King -of Bavaria, presided over by an eminent savant, Professor Kastner, -went to Rosstall to inspect the effects of the lightning discharge, -and Professor von Yelin did the same, as an independent, though not -disinterested witness. Their reports as to actual facts were the same. -The lightning, after striking the steeple of the church, had melted -the top of the ‘_Auffangstange_,’ or highest part of the conductor, -and further down had passed along the brass rope till coming to the -clock, only a few inches distance from it. Here the electric force had -evidently divided itself into several streams--the one exerting its -disastrous effects upon the clock and brickwork, and several metallic -objects underneath, and the other passing down the rope conductor, -but not without bending it, and, in one or two places, tearing it to -pieces. Such were the facts, visible to all eyes. But the conclusion -drawn therefrom differed widely. The members of the Royal Commission -made it public that the reason of the Rosstall lightning conductor not -having been efficient had simply arisen from its nature. Brass-wire -ropes, they declared, though perhaps useful against small discharges -of electricity, formed no reliable safeguards against powerful ones; -and they therefore strongly advised a return to the old-fashioned -iron rods. The conclusion was vehemently disputed by Professor von -Yelin. He admitted that it might be better, to provide for the proper -discharge of extraordinary masses of the electric force, to make his -brass ropes, when applied to high churches and other large edifices, -even thicker than they had been at Rosstall; but at the same time he -utterly denied that, even in this case, they had been the origin of the -disaster. He showed that the real cause of it was that the conductor -had not been laid deep enough into the ground, so as to touch moist -earth. The church stood upon sandy soil, on an eminence, and to touch -‘good earth’ the brass rope ought to have been sunk down to a depth of -at least fifty feet, whereas it did not reach one-third of that depth. -The professor was undoubtedly right, but his antagonists nevertheless -prevailed. A public prejudice, which no argument could overcome, set in -against brass-wire conductors, and they were pulled down from nearly -all buildings on which they had been laid, to be replaced by iron rods. -Some time had to elapse before real justice was done to metallic ropes -as lightning conductors. - -With our present knowledge of electrical phenomena, and the practical -art of making conductors, it may safely be affirmed that the Munich -professor was right in recommending ropes, though not in approving -of brass as the best metal. In its very nature, brass, a compound, -can never be thoroughly reliable, because its conducting power varies -according to its composition. The facility with which it allows the -electric force to pass through it depends, in fact, entirely on -the amount of copper which brass contains, and is greater or less -accordingly, since the other metal entering into its composition, -zinc, has less than one-third the same conductivity. Now brass is, for -various purposes, made sometimes of 70 parts of copper and 30 parts of -zinc, and again, only equal amounts of both metals, setting calculation -as to its conducting power entirely at nought. But besides this, brass -has the great fault of being excessively liable to destruction by -atmospheric influences, and it was found, among others, in Germany, -that while brass ropes were used as lightning conductors, they were -frequently destroyed, in a comparatively short space of time, by the -action of smoke alone. It is true, the Continental mode, existing -both in France and Germany, of spanning conductors over the tops of -chimneys--illustrated in the engraving here as a warning ‘how _not_ to -do it’--had much to answer for this atmospheric deterioration, since -even tougher metals than brass could not be expected to stand the -constant action of smoke, often containing sulphurous fumes. But even -without such an evidently absurd arrangement as that of running any -conductors, whether in the form of ropes or cords, across the orifices -of chimneys, brass could never have answered all the requirements of -a lightning conductor. It was with justice that brass-wire ropes were -nearly altogether discarded some thirty or forty years ago, after -having had a short-lived reputation. - -[Illustration] - -That copper should not have been employed, long before brass and other -metals, in serving mainly for lightning conductors, its pre-eminence -for this purpose being undisputed, would seem a strange fact, were -it not explicable on several grounds. The first was the cost of -the metal, which, though varying in price, is seldom less than six -or seven times that of iron. It was needless for the advocates of -copper as conductors--and there were not a few from the time its -high conductive power had been demonstrated--to say that if copper -was six times as dear as iron, it was likewise six times better as a -carrier of the electric force, and that consequently the price, in -respect of applicability for lightning protection, was in reality the -same. But the reply to this was that copper, being one of the most -expensive metals, except the so-called ‘precious’ ones, was exposed -to the temptation of theft, and ought therefore not to be employed, -since it was possible that vagrants, or other people, might tear off -at any time the, in more than one sense, valuable pieces of metal -protecting buildings against destruction from lightning. The argument, -perhaps, was not worth much, but a better one not mentioned was in the -background. It was, till quite recent times, an achievement of the -greatest difficulty to manufacture long rods or bands of sufficiently -pure copper to serve as lightning conductors. Sir William Snow Harris -attempted, as already related, to get over this impediment by taking -short plates, and fastening them together, and over each other, by -copper nails. But this process, besides being enormously expensive, -was in many other respects unsatisfactory, notably in that it made a -shifting of the plates possible, and by the destruction of a few of -them ruined the whole system. The pith and substance of the whole was -the technical difficulty of hammering or drawing pure copper out into -great lengths. That it must be pure was essential, the fact being -thoroughly established that the electric conductivity of copper, -mixed with impurities such as arsenic, is often not two-thirds, and -sometimes not as much as one-half, that of the pure metal. This was -conclusively shown by Sir William Thomson in a series of researches, -and likewise by that distinguished investigator in the conductivity of -metals, Professor Matthiessen. The latter, while placing copper on the -same rank with silver, and far above gold--100 to 78--furnished the -following instructive list as to the relative value of different kinds -of copper:— - - Pure copper 100·00 - Best American copper 92·57 - Australian copper 88·86 - Russian copper 59·34 - Spanish ‘Rio Tinto’ copper 14·24 - -It will be seen that, according to the investigations of Professor -Matthiessen, admitted on all hands to be correct, the copper lowest -in the list, the ‘Rio Tinto,’ is barely equal to iron in electrical -conductivity, and, not having the hardness of the latter metal, would -be in every way inferior to it as a lightning protector. The employment -of the purest copper therefore became an essential point in the -manufacture of lightning conductors. - -Fortunately, the difficulty was solved, at an earlier period than might -have been expected, by the demand for submarine cables. These had to -be made of wires of the highest possible electrical conductivity, and -the matter being one of high financial and commercial importance, -manufacturers soon began to use the utmost care in selecting ores -containing the smallest amount of metallic impurities. We believe -the lightning conductors now manufactured at the extensive works of -Mr. R. S. Newall, F.R.S., established at Gateshead on Tyne about -forty years ago, have generally a conductivity of 93 per cent. of -pure copper. It was laid down by one of the most eminent scientific -men of the day, not long ago, that the three principal qualities of -a good lightning conductor ought to be a maximum of conductivity, of -durability, and of flexibility that could be obtained, and there is -nothing coming up to this standard so well as ropes of pure copper. - - - - -CHAPTER X. - -HÔTEL DE VILLE, BRUSSELS, AND WESTMINSTER PALACE. - - -The systems of lightning-conductors used for the protection of -the Hôtel de Ville and Westminster Palace seem worthy of separate -description, as showing the methods employed by Professor Melsens and -the late Sir William Snow Harris, both eminent authorities in their -respective countries. The two buildings are so entirely distinct in -their character, that it will be seen at once that very different -methods had to be employed in rendering them safe from the effects of -thunderstorms. - -The Hôtel de Ville, Brussels, one of the finest Gothic structures -in the Netherlands, is fitted with an elaborate system of -lightning-conductors, erected under the superintendence of Professor -Melsens, a distinguished electrician and scientist. He has for many -years advocated the method of employing a great number of small -lightning-rods, in preference to one rod of large size, for the -protection of buildings from the effects of lightning; the main -characteristic of his system being that of covering the building with -a network of metal furnished with very many points, combined with -numerous and ample earth-contacts. This idea has been thoroughly worked -out at the Hôtel de Ville, Brussels; and probably no other building is -so completely guarded from the dangers of thunderstorms. The principal -feature of the Hôtel is a large central building, with a pinnacled -turret, from which rises a lofty spire, nearly three hundred feet high, -and adorned with four galleries, each with corner pinnacles. Upon the -top of this spire is a gilded colossal figure, seventeen feet high, of -St. Michael, holding a naked sword and standing upon a dragon. This -acts as a vane, and the point of the sword forms the highest terminal -conductor of the system. The main block of the Hôtel is ornamented with -six turrets, from each of which springs a small spire. In the rear is -a courtyard formed by buildings annexed to the front main block, and -composing the remaining three sides of this inner quadrangle. - -The figure of St. Michael, all the parts of which are rivetted and -soldered together, rests on a pivot of iron, three and a half inches -in diameter, which is deeply embedded in the stone-work of the spire. -The weight of the vane produces a metallic connection with the pivot, -and the top of the platform in which the pivot is fixed is covered with -sheet-copper. Around this and in connection with the pivot are fixed -eight perpendicular galvanised iron conductors, two-fifths of an inch -in diameter, and provided with five points each. A flash of lightning -striking the statue would thus reach the pivot and then be divided -between the eight conductors. Just below the platform are placed, at -an angle of 45 degrees, eight large points six and a half feet long. -These are fastened to an iron band which encircles the spire, and are -connected with the eight conductors by means of a mass of zinc. Thus -the pivot of the statue, and consequently the statue itself, the eight -conductors, the eight large points, and the forty small points on the -conductors, constitute a protection which dominates the edifice, and -represents a circular space of about five and a half yards in diameter; -that is, between the extremities of the large points which project from -under the platform. In this manner a flash of lightning is instantly -distributed and conveyed by the conductors to the ground. It may be -mentioned here that a thin copper wire, insulated by three coatings, is -fixed on the north side of the iron band in which the large points are -fastened; the other end of this wire is left free, and can be utilised -as a conductor for a rheometer or any other electric machine which it -might be thought proper to use permanently for the registration of -lightning striking the conductors. - -The eight conductors have each an unbroken continuity of about 310 -feet; and they collectively show a continuous section of nearly -one inch--almost half as much again as the limit of safety given -in the ‘Instruction’ of the Paris Academy. Although, in Professor -Melsen’s opinion, rods of somewhat less diameter would have been -amply sufficient for security, he chose the largest size which could -be easily bent to the varying contours of the building, and also -as allowing for the expansion and contraction caused by changes of -temperature. If conductors of only one quarter of an inch diameter -had been used they would, it is true, have shown a total section -just above the limit of the ‘Instruction;’ but, since Coulomb has -demonstrated that tensional electricity is more particularly carried on -the surface of bodies, M. Melsens thinks it is necessary to consider -the action that this surface might exercise in the easy transmission -of electricity. Some old German writers on this subject went so far -as to assert that the conductivity was proportioned to this surface. -They therefore recommended flat bands or hollow tubes in place of rods. -Although exact figures cannot be given as to the effect due to the area -of the surface, M. Melsens considers that it is unquestionable that -the relation of the section to the surface has a marked and definite, -although at present unknown, result. In the case of the Hôtel de Ville, -Brussels, he thinks the eight conductors possess a signal advantage -over one conductor, even though it had a larger section--say one inch. -Experience will doubtless teach how to determine more precisely the -extent of this surface-action. - -The eight conductors descend the length of the octagon of the spire -until they reach the first gallery; going round this they pass over -the balustrade, and then converge towards each other; are carried -over a prominence in the roof; and as they pass along gather up -other conductors of similar size from the ridges and parapets of the -buildings which form the quadrangle. Projecting vertically from these -horizontal lengths of the conductors are a large number of points and -aigrettes. The summits of the lower tower are also furnished with a -great many points. These eight main conductors are then taken down the -wall of the building into the courtyard, and at about three feet from -the ground are carried into a box constructed of galvanised iron, and -in it are connected into one solid mass by zinc, which has been poured -molten into the box. Almost throughout their length the conductors are -left loose, so as to remove all complication arising from dilatation; -the play of this dilatation being rendered easy on account of the small -section of the conductors, which bend readily. - -In accounts of lightning striking buildings which have been provided -with lightning-conductors, it is almost invariably found that these -conductors are incomplete, and have generally been fixed by persons -ignorant of the scientific questions involved. When the facts in -such cases are carefully examined it is found, as a rule, that the -defect is in the connection with the water underground, or in the -bad conductivity of the earth in which the conductors terminate. -In establishing a perfect communication with the earth, M. Melsens -considers it is necessary, not only to place the conductors in contact -with water, but also to see that the contact extends over a large -surface. The Paris Academy ‘Instruction’ recommends this precaution, -but in a very vague and too succinct a manner. To the above rule may -be added another condition, namely, that the earth-connection should -be large in proportion as the site of the building is redundant in -metal products in direct or indirect contact with the ground, the -subsoil, or the damp earth of the foundations, and sometimes even with -water itself. With regard to the metal contained in the materials of -buildings, it is not sufficient to establish a connection at one point -only, as is generally supposed. On the contrary, it is important that -all the metal-work should be connected with the conductor at least at -two points, in order to realise closed metallic circuits, and thus -offer an entry and exit, or a free metallic course, for the current of -electricity. The foregoing statements have been placed here chiefly -because the principles they convey have been so rigidly, and at the -same time successfully, carried out by Professor Melsens at the Hôtel -de Ville, Brussels. - -[Illustration: Fig. 3.] - -To return to the eight conductors and the earth-connections provided -for them. It has been shown that these conductors, after descending -the wall of the building, reach a point about three feet from the -ground, where they are embedded in a rectangular box of galvanised -iron, which is eight inches long, three inches broad, and three and a -half inches high. In the bottom of the box are three holes, through -which pass three series of eight conductors, each series being of the -same diameter as those which descend from above; the conductivity -being thus increased threefold. All of these are formed into one mass -by the zinc, which has been poured into the box in a molten state, -so that they constitute with the eight rods from above, one integral -conducting system. In the illustration which is here given the box -is represented by B, and the eight main conductors coming down from -the building by C C. The three series of rods numbered 1, 2, 3 show -the triplicated conductors issuing from the box. The first series is -placed in communication with the water by means of an iron pipe, which -carries it underground to a well. Here the rods are inserted in a large -tube six and a half feet long and nearly two feet in diameter (see -engraving). This tube is let down almost four feet below the level -of the earth, and sustained by two chains hung on two iron holdfasts -fixed in the side. The conductors C C are fastened to this tube in the -following manner:--A small length of straight iron cylinder is placed -outside the flange of the tube; and the ends of the conductors being -arranged between the cylinder and the flange, the space _a a_ is filled -with molten zinc; thus rendering the substance of the iron tube and -that of the conductors metallically continuous. The well into which the -tube is sunk furnishes perpetually a contact of eleven square yards -between the water and the iron of the tube. Into the space _a a_ is -also introduced a large number of small galvanised iron wires to act -as auxiliary conductors; these are terminated by being brought to a -point and soldered to the mass of zinc. In order to prevent as far as -possible the formation of rust, a large quantity of lime is thrown into -the well, in order to make the water alkaline. The second series of -conductors, painted with coal-tar, is placed in a covered metal gutter -and carried some distance to a gas-main in a spot where the earth is -moist. The conductors are fixed by means of a large copper plate, which -is soldered to the gas-pipe or main. On the copper plate are fastened -sixteen large-headed brass screws, to which the conductors are secured. -This arrangement is enclosed in brickwork, the wires being painted with -coal-tar; and a quantity of boiling tar is poured on the copper plate, -over which is laid a cloth, thus preserving the whole from oxidation. -The third series of conductors is carried in a gutter, similar to that -which contains the second series, to a water-pipe in the Place de -l’Hôtel de Ville, and the wires are fixed to it in the same way. - -[Illustration: Fig. 4.] - -It may be added that the whole of the conductors above-ground--with the -exception of the points--are painted with oil. - -Although it is correct that the coke generally placed around the -earth-connection of conductors aids by its good conductivity to bring -them in contact with a large surface of earth, Professor Melsens has -preferred to employ tar, which, it is true, is insulating, but helps -materially to preserve the conductors. It is estimated that the entire -contact between the earth and the underground surface of iron is about -300,000 square yards. - -Professor Melsens thinks it is worthy of note that, although copper -is a better conductor of electricity than iron, it has less molecular -strength. Where thin iron wire would simply be beaded--without losing -its conductivity--by an exceptionally strong charge of electricity, -copper wire of the same thickness would by a similar charge be -dissipated to a black powder. Professor Melsens has verified this -in some very interesting experiments. The large use of iron in his -system of conductors on the Hôtel de Ville, Brussels, was rendered -imperative by reason of the enormous cost of sufficient copper for such -an extensive system. But Professor Melsen’s experiments, nevertheless, -give some support to the selection of iron for large and complete works -of this kind. - -Sir William Snow Harris, in his arrangements for the protection of -the Palace of Westminster from lightning, has endeavoured to perfect -the general conductivity of the whole mass of the building, and so -make it assume the same relation to the electric discharge as if it -were a complete mass of metal. Westminster Palace differs in one -important respect from the Brussels Hôtel de Ville--the general level -of the roofs is covered with iron coated with zinc, and in many places -directly connected with the earth by cast-iron water-pipes. The roofing -thus constitutes, although imperfectly, and only to a limited extent, -a protection of itself. Sir William Snow Harris had, therefore, -chiefly to provide for those portions of the building which are above -the general level of the roofs, and, by the use of ample conductors -of copper, to make up for the comparatively low conductivity of the -roofing and the iron pipes which connect it with the earth. - -From the terminal which forms the highest point of the large central -tower is brought a copper tube of two inches diameter and one-eighth -of an inch in thickness, the joints of which are secured by solid -screw-plugs and coupling-pieces. This tube is carried down in the -south-west angle of the tower and fastened to the masonry by metallic -staples. At the junction of the tower with the roofs the tubing is, or -at any rate was, thoroughly connected with the metal of the roof, and -then continued to the earth in as straight a course as practicable, -and there terminates in two projecting branches made of solid copper -rod. By carrying this copper tubing direct to the earth, instead of -terminating it in the metal-work of the roof, the electrical discharge -obtains a conducting medium of the same power throughout, in place of -having to leave a high power for one of lower conductivity. - -The Victoria and Clock Towers, which are each 300 feet high, are both -fitted with a copper band, five inches wide and a quarter of an inch -thick. These run down the walls, and are connected with the metal of -the roof, and also with the metallic rail of the staircase within each -tower. The ornamental turrets and pinnacles of St. Stephen’s Porch -are protected by small bands of sheet-copper, two inches wide and -one-eighth of an inch thick; these are also placed in connection with -the metal of the roof. - -The north and south towers of the central block, and the north and -south wing towers of the front facing the Thames, have attached to -them bands of sheet-copper running from their respective vanes to the -roofing below. The bands are connected with the metal of the roof, and -are then carried down independently to the earth, in a similar manner -to that adopted on the large central tower. - -The only other prominent portion of the edifice is the ventilating -shaft of the House of Commons, where, during the sitting of Parliament, -a coke-fire is generally burning, and from which, therefore, a stream -of warm and rarefied air is constantly being emitted. The conductivity -of an ascending column of warm vapour is known to be great, and -accidents from this cause are of frequent occurrence, although very -often they are not ascribed to their true source. To obviate this -danger, the ventilating shaft is provided with a copper tube conductor, -fixed on its eastern side, and connected with the metal of the roof. - -This short description of the measures adopted by Sir William Snow -Harris for the protection of Westminster Palace contains all the -salient points of the system which at that time, some twenty years -ago, was doubtless the best that could be devised. But, although -nearly 4,000_l._ was spent upon this work, from that time to this, as -far as can be ascertained, these lightning-conductors have never been -tested! It is therefore very possible, and indeed probable, that on the -occurrence of any very heavy thunderstorm they would be found wanting, -and considerable damage would ensue, the extent of which no one can -estimate. - -[Illustration] - - - - -CHAPTER XI. - -WEATHERCOCKS. - - -Although such an opinion seems scarcely orthodox, it may, and not -unreasonably, be doubted whether weathercocks are of any great use in -demonstrating the direction of the wind. The under-currents of air are -so numerous and so conflicting--especially in towns where the houses -are lofty--that it is quite possible for two weathercocks at different -ends of the same street to show at the same moment the wind blowing -from opposite directions. However, the prevailing custom of placing -these ornaments, in connection with lightning conductors, on the -highest points of large buildings renders necessary some explanation of -the manner in which they should be fixed; for if they are improperly or -negligently attached to the lightning conductor, the continuity of the -latter may be rendered defective, or at least seriously impaired. - -The two main points to be kept in view are, that the weathercock should -move freely with the wind, and that the continuity of the lightning -conductor should be preserved. One method of obtaining this result is -to put the weathercock into a circle, with the terminal rod of the -lightning conductor on the top. This is called the ‘nimbus cock,’ and -is in somewhat doubtful taste. The continuity, however, is perfect, and -the cock, which is simply placed on to a point, moves easily with the -wind. An example of this cock may be seen erected on the central finial -of the Cathedral at Amiens. - -[Illustration: Fig. 5.] - -A different way is to make the terminal rod of the conductor serve as -a pivot for the cock, as shown in fig. 5. This is the usual kind of -weathercock used in England, and is considered by many to be one of the -best forms. It is arranged in this manner: the actual terminal of the -conductor ends with a rounded or sharp point of steel, and acts as a -spindle, on which the weathercock revolves. It varies in diameter from -five-eighths to three-quarters of an inch. A tube, from seven-eighths -of an inch to one inch in diameter, and on which is fixed the cock, is -made to fit on to this terminal or spindle. This tube contains at the -extremity of its interior a piece of steel or glass, or sometimes a -glass ball, and being lengthened to a point, with a platinum or copper -tip, serves as the point of the lightning conductor. This weathercock -is generally called a ‘formed cock;’ it measures at its extreme length -about twenty-one inches, and weighs about twelve pounds. It will be -seen that in this method there is nowhere absolute contact between the -point and the pivot; consequently electric sparks must be caused by -the current of electricity. Besides this defect, if the metal becomes -oxidised between the surfaces, insulation will be the result. This -plan, though often adopted, sacrifices the principal for the sake of -the accessory. - -[Illustration: Fig. 6.] - -Fig. 6 shows another method of fixing the weathercock on to the -conductor. It is called a ‘solid cock,’ and is cut out of sheet-copper -one-sixteenth of an inch thick; it revolves on a spindle in the manner -shown in the engraving. This spindle, on which the cock or ‘blade’ -works, differs in diameter according to the weight of the bird, the -height and style of the building, &c., but as a rule it is from -five-eighths to three-quarters of an inch in diameter. - -It is usually used for Gothic buildings and private mansions, but -should not be adopted, as it is apt to be lifted off its spindle by -the wind. When a down-current of wind takes place there is generally -an up-current at the same time, and there is a possibility of the cock -being blown off during a gale. If it is used it should have a long -point fixed above it. - -[Illustration: Fig. 7.] - -A better arrangement than either of the two preceding ones is to let -the point go quite through the weathercock in an encasement. The -cock is then supported on a small round embasement, upon which are -placed three small rollers (see fig. 7); on these the vane revolves -easily, the continuity of the lightning conductor is perfect, and -the weathercock freely turns round on the point so long as the small -rollers are in order. In this arrangement, as in most others, the best -material for the point is copper. Steel has occasionally been used, but -it was found that in a very short time the rust had so eaten into the -joints that the cock would not turn with the wind. - -The most complete and enduring method is that indicated in figs. 8 and -9; this is the plan adopted in England for all the best work. By this -arrangement, the friction being very much diminished, the weathercock -revolves with great ease and freedom; the possibility of its getting -out of order is reduced to a minimum; and the continuity of the -lightning conductor remains unimpaired. - -[Illustration: Fig. 8.] - -[Illustration: Fig. 9.] - -It is accomplished in this way:--A circular plate, through the centre -of which the point passes, is permanently fixed some distance down -the point. On this circular basement rest three glass balls, rolling -on three axes radiating from the centre, i.e. the point, and fixed in -their outward extremities to a ring which surrounds the balls (see -fig. 9). On these balls is placed another circular plate, on which is -fixed the weathercock. The weathercock and circular plate, with a hole -through the centre, is simply put on to the point of the conductor, and -allowed to rest loosely of its own weight on the balls of glass. - - - - -CHAPTER XII. - -LIGHTNING PROTECTION IN FRANCE AND AMERICA. - - -In this chapter it is proposed to give a brief _résumé_ of the -different systems of constructing, erecting, and repairing lightning -conductors in France and America. The laws of electricity being the -same all the world over, the methods employed in these countries are -necessarily similar in their essential principles; nevertheless they -vary somewhat in detail, both from each other and from the work of the -best firms in England. - -Until a very few years ago the lightning conductors throughout France, -although many in number, were in a very neglected state. Badly -constructed in many cases, their original faults had grown worse -from want of attention. The connection of the terminal rod with the -conductor was generally made by means of a strap or iron collar, which, -after a short time, rusted to such an extent that the continuity was -practically reduced to nothing, and the conductor, so far from being a -protection to the building, was a positive danger to it. - -Latterly, however, a reaction has taken place, and a more careful -method of connecting the various joints of the conductor has been -contrived, or rather, revived, and a better system of periodical -inspection and testing is carried out. - -[Illustration: Fig. 10.] - -[Illustration: Fig. 11.] - -Under the French system, what is called in England a lightning -conductor, and to which the French give the name _Paratonnerre_, is -nominally divided into three parts: the terminal rod, the conductor, -and the _racine_, or root, i.e. the earth connection. With regard to -the terminal rod, the ‘area of protection’ theory is, in France at any -rate, still believed in by a great many people. In that country, as -a rule, it is made of wrought iron in a single length, and polygonal -or slightly conical; its height depends upon the size and area of -the building it protects, the general presumption being that, under -ordinary circumstances, a terminal rod will protect effectually a cone -of revolution, of which the apex is the point of the rod, and the -radius of the base a distance equal to the height of the said rod above -the ridge, multiplied by 1·75. Thus a rod rising eight yards above the -ridge of a building would effectually protect a cone-shaped space, the -base of which, at the level of the ridge, has a radius of 8 × 1·75 = -14 yards. In actual practice somewhat wider limits are allowed. The -height of the terminal rod having been determined according to the -circumstances under which it is erected, it is then galvanised with -zinc in order to prevent oxidation, and the connection between the -terminal rod and the conductor is formed by means of the following -arrangement. A little above the base of the terminal rod, say about -eight inches from the roof of the building, a flange A (see fig. 10) is -welded with a hole pierced through it. Through this hole the conductor, -previously filed down to the proper dimensions, must be tightly passed. -After scraping the iron around the hole, a washer of lead is placed at -P and P´ (see fig. 11), and the button B, by means of a strong layer of -solder, thoroughly binds everything together. In this way an excellent -joint is obtained; the contact surface is considerable, and, if the -work is carefully done, the joint is completely preserved from rust. - -[Illustration: Fig. 12.] - -The point of the terminal rod, although sometimes made of platinum, -generally consists of either pure red copper, or, what is considered -still better, an alloy of 835 parts silver and 165 parts copper. It is -fastened to the terminal rod in the manner shown in fig. 12. - -C is the trunk of a red copper cone, upon the top of which a point, P, -made either of platinum or of an alloy of silver and copper, as before -mentioned, is screwed, pinned, and strongly soldered with pewter solder -at _a_, the whole being screwed on to T at _b_. To ensure complete -contact and continuity, a washer of freshly-scraped lead is inserted -between C and T, and the whole of the joint thickly covered with a -layer of pewter solder. It may be added that the point forms an angle -of fifteen degrees with the vertical, consequently the point terminates -in an angle of thirty degrees. - -[Illustration: Fig. 13.] - -For the conductor of the ‘paratonnerre’ lengths of iron bars are -principally used; formerly these were jointed together by means of a -pyramidal bolt let into a notch of the same form, and connected by -a simple iron pin. This method, however, was discovered to be very -bad, as it failed to preserve the continuity of the conductor after -it had been erected a little time. The following plan, as represented -in fig. 13, is now used for the best work, as being more durable and -affording a better contact. On each side of the bars to be joined, two -flanges, about six inches long, and half the thickness of the bars, -are filed out. A thin piece of carefully-prepared lead is then placed -between them. The whole is then firmly fastened together by bolts at B -and B and completely covered with pewter solder, and thus furnishes a -solid, durable contact which possesses very small resistance. - -Formerly the conductors were, at regular intervals, rivetted to -cramps let into the wall for the purpose of retaining the conductor -in its place. As this plan left no room for the play of expansion and -contraction caused by variations in the temperature, it was found that -at times the conductor was very much strained and even bent by reason -of this expansion and contraction. To avoid this evil an apparatus, -which has been approved by the Paris Academy of Sciences, has been -substituted for the cramps and rivets. This apparatus consists of a -fork in which the conductor is held fast by a pin (see fig. 14). Being -able to move backwards and forwards in the fork with great facility, -the conductor is thereby permitted to expand or contract under the -influence of temperature without threatening its supports with -destruction. - -[Illustration: Fig. 14.] - -The question however arises, upon what part of the paratonnerre ought -the effect of such contraction or expansion to be borne? The Paris -Academy of Sciences has sanctioned and recommended the use of a -compensator, which is designed to bear this strain. This compensator, -which is now much used in France, may be seen in fig. 15. It is -composed of an elastic plate F, made of well-annealed red copper, -three-quarters of an inch wide, at least twenty-eight inches long, and -about a quarter of an inch thick. The two extremities of this plate -are firmly fastened to the two ends of two lengths of the conductor -by the bolts and counterpieces B B´, and afterwards covered with a -thick coating of pewter solder. When, in consequence of the heat, the -conductor expands, the curve of the copper plate F will become greater, -and in cold weather it will become less. As a rule, a single apparatus -is supposed to compensate for the effects produced by long straight -lengths, and it is therefore thought sufficient to place one at each -bend. - -With the exception of the terminal rod, it is the rule in France to -cover the whole of the paratonnerre with some coating in order to -preserve it from contact with the air. This is attained by covering it -with either a strong coat of tar, or a painting of a metallic basis, -such as zinc or tin filings. - -[Illustration: Fig. 15.] - -In larger buildings what is termed a ‘ridge-circuit’ is often used. It -consists of an unbroken metallic connection running along the ridges -of the building to be protected, and connected with the conductors -and terminal rods, and consequently with the subterraneous sheet of -water which forms the common reservoir. It is made of lengths of -square iron bars or rods having a thickness of about three quarters -of an inch square, and fastened together by overlaying the ends, -bolting them together with two bolts, and covering them well with -solder in the manner shown in fig. 13. New branches are formed by -T-shaped connections, the cross-piece of the T overlaying the original -ridge-circuit, and the stem making the first length of the new branch. -In some cases the ridge-circuit rests directly on the ridge of the -roof; but in order to avoid injury during the repairs to the roof or in -other ways, the plan adopted in good work is to raise it some distance -above the ridge on supports at suitable distances, and thus prevent the -possibility of damaging the joints and solderings. - -The form and arrangement of these supports depend on the nature of the -roof. Sometimes forked uprights are used--these allow for the expansion -and contraction due to changes of temperature; in other cases simple -cast-iron bearings, weighing from ten to twelve pounds each, are laid -upon the ridge, their upper surfaces being grooved to receive the bars -of the ridge-circuit. - -All masses of metal used in the construction of the building are -metallically connected with the paratonnerre. As a rule, this is -done by pieces of iron about half an inch square, which are strongly -soldered to the metal surfaces, and then connected with some part of -the conductor or ridge-circuit. - -Although in France, as elsewhere, all experts are agreed as to the -prime importance of the disposition and arrangement of the _racine_ or -earth-end of the paratonnerre, a difference of opinion prevails as to -the best means of insuring a good earth-contact, and many methods have -been tried, all of them similar in principle, but differing somewhat in -application. It is proposed to give here a brief outline of the best -contrivances employed for this purpose. - -One main object, in arranging the earth terminal of a lightning -conductor, is to avoid the gradual destruction of the _racine_ by -the action of alternate dryness and moisture which, unless the iron -is protected in some way, corrodes, and eventually eats it entirely -through. There are several ways of remedying this evil. In France it -is common to find used for this purpose a vertical spout of tarred, -boucherised, or creosoted wood, rising a few inches above the soil. -Some authorities recommend the simple plan of covering this part of -the conductor with a strong coating of tar, others covering it with -a wrapper of sheet lead, and this last method is probably the best. -With regard to the extreme end of the conductor, the system approved -of by the Paris Academy of Sciences is generally used in good work. -This system is the use of a trough filled with broken charcoal, through -which the conductor runs; charcoal preventing the too rapid oxidation -of the iron. For charcoal, coke may be substituted. The trough (see -fig. 16) is made either of wood, gutter tiles, or ordinary bricks -without mortar, so as to allow the moisture of the soil to permeate -through. It is preferable, even at the expense of lengthening the -conductor, to carry it through the lowest and dampest plots of ground -around the building. - -[Illustration: Fig. 16.] - -To obtain a perfect contact between the end of the conductor and the -earth, or common reservoir, the French use several methods. One of -the earliest ones was the multiplication of the iron bars attached to -the end of the conductor, and inserting them for some distance into -well-water. Theoretically this arrangement is good, but it has been -found that the decay of these terminals by the action of rust was -so rapid that, unless they were carefully watched and periodically -repaired, they soon became insufficient, if not useless. In addition -to this, it is the opinion of many French savants that a mere water -contact is not enough, a soil that is always moist being in their -judgment far preferable. The simplest plan adopted for attaining this -end is that of inserting into the moist ground to a certain depth, -regulated by the nature of the soil, one or several metallic branching -stems, which are connected with the conductor. By another arrangement, -invented by M. Callard, the conductor is terminated by a kind of -galvanised iron grapnel, placed in a wicker basket filled with pieces -of coke. Where the soil is dry, and moist ground cannot easily be got -at, the harrow or grating shown in fig. 17 is often used. It is placed -between two layers of horn embers, or charcoal, and sunk as deeply -as it conveniently can be, the end of the conductor being carefully -connected with it by soldering or by a quantity of melted zinc. - -In towns, the water-pipes and gas-mains, possessing as they do, -large metallic surfaces, are generally utilised for making the -‘earth-contact.’ - -[Illustration: Fig. 17.] - -Sometimes, instead of iron bars, galvanised iron cables of about an -inch in diameter are used for the conductors of paratonnerre, and -occasionally red copper cables of half-an-inch only in diameter, but -the use of these latter is uncommon. - -[Illustration: Fig. 18.] - -Fig. 18 exhibits a modification of the point of the terminal rod which -is advocated by M. R. F. Michel. The arrangement is based on the -principle that, on the approach of a tempest cloud, the more points -there are, the greater will be the neutralising effect. M. Michel -considers that when a terminal rod has only one point, it acts only -in one direction; but if there is a large number of points branching -in all directions, the preventive action is materially increased; he -therefore proposes the use of this contrivance, which is carried out -by having the ordinary conical trunk copper point on the top of the -terminal rod melted down, and moulded so that it presents in its middle -a circular swelling. Into this swelling arrows are fixed, inclined at -each side of the horizontal plane to an angle of 45 degrees, as shown -in the engraving. These arrows radiating in all directions are supposed -to ‘hasten the neutralisation of the electrified cloud; and in the -event of a discharge, the discharge, by dividing amongst them, will -prevent their fusion.’ - -Before quitting the French system, mention should be made of a novel -form of lightning conductor devised by M. Jarriant. This gentleman -proceeds on the hypothesis that the most essential requisites of a -lightning conductor are:--a terminal rod metallically homogeneous, -which should rise to a good height; that it be sufficiently light -to avoid damage to the roof, and yet be strong enough to resist the -violence of the wind. To attain these requirements, M. Jarriant secures -his conductor with three or four stays, which are firmly fixed to the -roof and converge to the top of the terminal rod, to which is fastened -the ordinary copper point, recommended in the ‘Instruction’ of the -Academy of Sciences. Iron supports are placed at different heights in -order to ensure the perfect solidity of the system. Galvanised iron -is employed, and all the various stays and supports are metallically -connected with each other. The angles of the irons are all acute, -and placed so as to offer the least resistance to the wind. The -advantages claimed for this method are that the upper part of the -conductor bristles with spikes and aigrettes, which he considers a -great advantage in regard to the preventive effect produced by the -conductor; it allows of the conductor being raised much higher above -the building; it presents a large surface to the electrified cloud; the -joints are so arranged that they cannot be dislocated by the expansion -and contraction caused by variations of temperature; and, lastly, it is -affirmed that these conductors cost thirty per cent. less than those -erected under the ordinary system. - -America stands pre-eminent above other countries in the numerous and -extraordinary schemes that have there been promulgated in regard to the -protection of buildings from the effects of lightning, and probably -no other nation has been so systematically victimised and swindled in -this matter. The tramping ‘lightning-rod men’ of the United States are -notorious for extortion and ignorance: they use all kinds of fantastic -and peculiar shaped terminal rods and conductors, the main object -being to make as great a show with as little metal as possible. Their -work is almost entirely confined to the upper portion of the conductor, -to the neglect of the most important part--the earth terminal. In -consequence, the majority of the lightning conductors in America are -untrustworthy; very often they are practically insulated from the -‘common reservoir’ or subterraneous water, and are therefore more often -a source of danger than a protection. Unhappily, these peripatetic -mechanics are by no means extinct, although increased knowledge is -gradually driving them from the field. - -In America, a strong point is made of utilising, as far as possible, -all the existing natural conductors that are to be found upon a -building, such as gutters, rain-pipes, and other metal surfaces. During -a tempest, the opposite electricities of the earth and the air often -select, by their inductive influence, a rain-pipe, gutter, metal roof, -&c., for the passage of an electric discharge between them, and unless -these metallic surfaces are connected with the earth, they are apt to -be dangerous. But if they are properly connected together, and provided -with a good earth-contact, they materially assist to diminish the -intensity of a discharge. - -In the case of a building with a roof of slate, wood, or other material -of low conductivity, a conductor made of either bar iron or stranded -cable is placed along the ridge and gable ends, and carefully connected -with the gutters and rain-pipes; where the rain-pipes are less than -three inches in diameter, the bar or cable conductor is often extended -from the roof down the side of the building, and connected with the -earth terminal. When this is done, the bar or cable conductor is placed -between the rain-pipe and the wall of the building, or at any rate -close to the rain-pipe, and connected with it by solder or bolts. - -All metallic chimney caps, cornices and railings on the tops of -buildings, as well as the water-pipes, gas-pipes, hot water-pipes, -and other large or long pieces of metal, whether they occur inside or -outside the building, are connected with each other by a conductor -composed of light stranded wires, each about three-sixteenths of an -inch in diameter; they are also connected with the main conductor -at its nearest point. Where several adjacent buildings have each -a metallic roof, these roofs are connected together by means of a -horizontal conductor. - -The terminal rod of the conductor generally projects about four feet -above the chimney or other highest point of the building. It consists -of a round iron rod seven-sixteenths of an inch in diameter, the lower -extremity being hammered out for the purpose of fastening it to the -conductor by soldering and screws or by bolts. A small building, not -exceeding twenty-five feet in length or breadth, is generally fitted -with either one terminal rod placed on the centre of the ridge of the -roof, or with two rods, one at each end of the ridge, the latter method -being the preferable one. In larger buildings terminal rods are placed -at intervals of about twenty feet along the roof. The upper end of -the rod is sometimes pointed, but not always, the argument being that -although the ordinary end of a rod is blunt when used in connection -with a Leyden jar, but that when applied to a thunder-cloud, which -extends over thousands of acres, it becomes pointed, and bears the -same proportion to a thunder-cloud as the sharp point of a needle does -to the hand of a man. Occasionally the point is tipped with platinum, -gold, silver, or pure copper, in order to prevent oxidation, but this -is not considered essential, it being presumed that, practically no -amount of rust on the top would impair the efficacy of the terminal rod. - -In the case of a building having a flag-staff upon it, a galvanised -iron wire is fastened along it and projects about six inches above the -top, the lower end of the wire being of course carefully soldered or -otherwise connected with the main conductor. - -Steeples and spires, in addition to the ordinary vertical conductor, -are fitted with horizontal conductors placed around them at intervals -of about twenty feet, and connected with the vertical conductor. This -is to provide against the occasional discharges that take place in -the centre of steeples, and which are caused by the deflection of the -discharge in the air by the rain. - -Chimneys and air shafts, from which heated air or smoke escapes, -are fitted with metallic caps which are connected with the general -conductor. In order to protect this metallic cap from the effects -of the sulphurous fumes arising from the chimney, a terra-cotta cap -is contrived to fit inside the metallic cap. An analogous method is -adopted with regard to the ventilators of barns and ice-houses. If -these buildings have the ordinary ventilators in the form of dormer -windows upon the roof, an iron rod seven-sixteenths of an inch in -diameter is placed vertically across, and above the centre of the -opening of each ventilator, and connected with the conductor. Should -the barn or ice-house have openings or doors through which warm vapour -can escape, a conductor is fixed to the roof at the gable ends above -the centre of each opening or door, and extended outwards about five -feet, at an angle of forty-five degrees from the roof, so as to be in -line with any ascending vapour, or any descending charge of electricity -following the course of the vapour. All these auxiliary conductors and -terminal rods are metallically connected with the main conductor of the -building. - -The conductors are simply fastened to the building by iron staples or -by straps of sheet iron, pierced with two holes for nails or screws. - -In America, as elsewhere, the earth-terminal is regarded as of prime -importance, and in all properly constructed lightning conductors -receives the greatest care and attention. In the first place, such -metal pipes as lead from the building to the water-mains, gas-mains, -and sewers are carefully connected with the principal lightning -conductor, in order that they may act as auxiliary earth-terminals. -For the principal earth-terminal many contrivances have been brought -forward, but very few possess any originality, and many are positively -useless. Some of the best are similar to those in use in England; -among others, perhaps the best method is that of placing a cast or -wrought-iron pipe of three inches inside diameter, and about ten feet -long, vertically in thoroughly moist earth and carefully connecting the -conductor, or conductors, with it. The chief objections to this plan -are the occasional difficulty of getting a moist earth at all, and the -possibility of earth that is generally moist getting dried up in hot -weather. To obviate these risks, the following arrangement is used:— - -In a pipe of wrought or cast iron, at least ten feet long, and having -an inside diameter of two inches with a thickness of three-eighths of -an inch, are made a number of longitudinal openings or perforations, -about ten inches long and a quarter of an inch wide. These openings -or perforations are made at intervals of ten inches, and are placed -in one or two lines opposite to each other. If it is preferred, round -holes of from half an inch to one inch in diameter, and about six -inches distant from each other, may be substituted for the longitudinal -openings. This perforated pipe is placed in an upright position in the -earth, and is so situated that it receives at its top opening the waste -or rain water flowing along a channel or drain constructed for that -purpose. The water, after running into the top of the pipe, gradually -percolates down, and passing through the perforations or openings into -the earth around and underneath the pipe, moistens it to such an extent -and at such a depth as to render it but little affected by the heat of -the sun. The pipe is generally placed at some little distance from the -building, so as to give a sufficient area of earth to be kept moistened -and to prevent the walls of the building being affected by the damp. - -Occasionally, the pipe is made triangular or square, and with -perforated branches and other metallic conductors. It is also sometimes -constructed with enlargements at the top or bottom, so as to hold more -water. Probably, however, the simplest plan is the best, as--if the -soil be suitable--a plain round wrought-iron pipe can be driven into -the earth. If a cast-iron pipe is used, a hole of a convenient size is -excavated for it. In this case, great care has to be taken that the -earth is thoroughly well rammed down all round the pipe. - -Another arrangement is to employ, instead of a cast or wrought-iron -pipe, a number of round or flat-iron bars, fastened together at the top -and bottom by rivetting to metal hoops in such a manner that intervals -are left between each bar, through which the water can pass. Sometimes -a solid pipe without the openings is used, but it is not found to be -so satisfactory as the perforated pipe, because the latter allows a -greater amount of water to pass through it into the soil, thereby -furnishing a larger area of moist earth. - -The French method of carrying the conductor to the bottom of a -neighbouring well is frequently adopted where it is practicable, and -the water of the well is not required for drinking or cooking purposes. - -A few words may be added here on the method of protecting the large -mineral oil tanks which are to be found in the United States. Many of -these oil tanks are of very large capacity, some of them containing a -million gallons of oil. They are generally constructed of thick iron -plates rivetted together. The roofs are usually made of wood coated -with tar, but in some cases iron is adopted. As a rule, several of the -tanks are grouped together and connected with each other--and in some -instances with distilleries--by means of subterraneous iron pipes. - -One method of protecting these tanks is to erect around them, at -a distance of some ten feet, wooden supports, on which are placed -upright metallic conductors which overlook the tank, and are connected -with each other near their tops by stout iron wires, thus forming a -network of conductor which is supposed to intercept any discharge of -electricity from a tempest-cloud, and prevent it from reaching the oil -tank. This method, however, has failed in several notorious instances, -and is not countenanced by the best authorities. - -A better and less complex arrangement is now usually adopted by the -best firms. The chief object of this arrangement is to prevent the -temperature of the oil tank, and of the atmosphere above and around it, -being raised by means of an electric discharge. This is accomplished -by using large conductors, which are carried some distance above the -oil tank. These conductors, of which there should be at least four, -are formed of flat iron bars about one and a half inches wide and -half an inch thick; they are securely fastened to the sides of the -tank at equal distances from each other, and metallically connected -with it. About thirty feet above the roof of the tank they meet, and -are carefully and substantially joined together, and supported, if -necessary, by a wooden post extending from the centre of the roof of -the oil tank. - -The earth terminals, of which there must be one to every two -conductors, consist of perforated iron pipes, as before described, -three inches in diameter and fifteen feet long. They are sunk into -thoroughly moist earth, and metallically connected with the lower part -of the tank. These perforated pipes are so arranged that they catch the -rain water from the roof of the tank; by this means the surrounding -earth is kept moist. It may be mentioned that by utilising the tank -as a portion of the system of conductors, the electric discharge is -distributed and much weakened. - - - - -CHAPTER XIII. - -LIGHTNING PROTECTION IN ENGLAND. - - -In its essence there cannot be anything more elementary than the theory -of protection against lightning. It is simply to lay a metallic line -from the top of a building, or other object to be protected, into moist -ground, so as to make a path for the electric force, along which, -not finding impediments, it will travel freely, without causing the -least damage. But, like many other simple theories, their practical -execution is not without perplexities. The first of these, in regard -to conductors, arises from the existence of more or less considerable -quantities of metals, to be found in almost every building which -requires protection against lightning. As the use of metals, especially -iron, in the construction of dwellings, both exterior and interior, -is rapidly extending, this becomes a very important consideration -in planning the design of lightning conductors. Of equal moment is -a second point--that of the existence of water or great moisture -under the buildings, or part of them. This must decide invariably -the direction of the conductor towards the earth, and its depth -underground. There are many minor matters to be taken into account, but -these two may be laid down as the chief questions to be kept in view -in settling the best mode of application of any conductors under given -circumstances. It happens often enough that a proper solution as to -what is best is not a little difficult. Still, it can always be arrived -at by careful study, which must, however, be aided by experience. - -Keeping always in view the fact that there is nothing whatever that -may be called ‘erratic’ in the manifestations of the electric force, -but that it acts under a ruling principle as strict as that governing -the law of gravity, the first point in designing the protection of any -building will be to clearly ascertain what path the lightning will take -on its course from the clouds to the earth. It is absolutely certain -that the electric force will make its way through materials, termed -good conductors, which allow it free passage, and avoid those of the -opposite class, or bad conductors, the character of every substance on -earth being well known as regards these qualifications, although it -would not be easy to draw sharp lines of demarcation, all conductivity -being relative and not absolute. Looked at in this way, the fundamental -one in the application of lightning conductors, the simplest object for -protection will be a pyramid of stone, such as the Egyptian obelisk, -popularly called ‘Cleopatra’s Needle,’ erected on the Thames Embankment -in the summer of 1878. Stone being a bad conducting material, all that -is necessary to protect it against lightning, provided there is no -metal whatever near it, is to run a thin strip or rope of copper from -the summit to the base, and down into moist earth. Although fragile, -the strip of copper, if uninterrupted and rooted in moisture, will in -this case form an absolute protection. The question assumes another -aspect if, instead of a stone pyramid, a tall factory chimney, not -very dissimilar in outward form, is given as an object for protection. -Here there enters another element. A tall pile of bricks is as bad a -conductor of electricity as a solid mass of stone, but the mass of -bricks constituting a factory chimney is hollow, and the cavity being -filled with smoke and mineral fumes, which are more or less good -conductors of the electric force, the artificial path laid for the free -passage of lightning has to surpass in acceptability the natural one. -In other words, the copper rod laid alongside the factory chimney, to -secure it against damage from lightning, must be considerably thicker -than the one which will protect the simple stone pyramid. It is this -principle which has to be followed all through in the application -of conductors. They must form, in one word, the best path which can -possibly be made for the electric force. - -The system employed by Mr. R. S. Newall, F.R.S., for the construction -and erection of lightning conductors is probably the most complete--and -certainly the most representative--of the various methods in vogue in -England. The special study Mr. Newall has made of the subject in all -its bearings, both theoretical and practical, added to the fact of his -possessing at his extensive cable works at Gateshead such exceptional -facilities for the production of copper ropes and bands composed of the -purest metal, render him one of the first authorities on all matters -connected with the application of lightning conductors to buildings. In -describing, therefore, the English method, reference will chiefly be -made to this gentleman’s apparatus and inventions. - -The function of a lightning conductor is twofold. In the first -instance, it operates as a medium by which explosions of lightning, -or, to speak more accurately, disruptive discharges of electricity, -are led to the earth freely, and without the risk of their acting -with mechanical force, as they invariably do when compelled to pass -on their way to the earth through so-called non-conductors, that is -to say, bodies possessed of low conductivity, such as the atmosphere, -wood, stone, &c. In the second instance, the conductor acts as a means -whereby the accumulation of electricity existing in the atmosphere -is quietly drawn off and carried noiselessly into the earth, and -dissipated in the subterraneous sheet of water beneath it. Now this -accumulation of electricity, always greatly intensified during a -thunderstorm, invariably seeks the easiest road to earth; this road is -technically called ‘the line of least resistance.’ This line of least -resistance is influenced by various circumstances; the resistance of -any line may be lessened by the presence of streams of warm vapour or -rarefied air such as would come from chimneys, from barns or stacks -containing new hay; by a column of smoke, or by the presence of tall -trees moist from rain. It is not always easy to find the reason why -the lightning takes any particular path, but one thing is certain, -that is, it acts under certain fixed principles, and does not take any -particular route by chance, but always because it is the line of least -resistance. What the lightning conductor really does is to prevent the -possibility of an electric discharge within a certain district, for -instance, in the interior of a house or other building. - -From the above remarks, it will easily be seen that lightning -conductors should be made of materials possessing the highest possible -power of conductivity, and be large enough to carry off the heaviest -electric discharge that is ever likely to fall upon them. The various -metals being by far the best conductors of electricity, it follows that -the lightning conductor must be constructed of metal of some kind. -But even metals differ to a great extent in their conducting powers, -as has been shown in a previous chapter. There are, however, only two -metals which are practically available for use as lightning conductors, -namely, iron and copper, and after repeated experiments Mr. E. S. -Newall has arrived at the conclusion that a conductor made of copper -of adequate size is the best--and, in the end, the cheapest--means -of protecting buildings from the effects of lightning. The relative -conductivity of iron and pure copper being as six to one, it follows -that if a copper cable or bar of a given size be sufficient, an -iron cable or bar ought to weigh six times as much per lineal foot -in order to be equally safe. It may be added, that while copper is -more expensive, weight for weight, than iron, it is not so liable to -oxidise; nor, on account of its higher conducting power, is it so -easily fused. The comparative smallness of its mass renders it far more -manageable than iron, and does not interfere with the architectural -features of the building on which it is used. On the contrary, it is -readily adapted to curves and angles. - -It may therefore be taken for granted that, almost without exception, -pure copper is the best material that can be used in the construction -of lightning conductors. - -[Illustration: Fig. 19.] - -[Illustration: Fig. 20.] - -[Illustration: Fig. 21.] - -The size of the terminal rod or point used in Mr. Newall’s method -varies in length and diameter according to the extent and height of -the building to be protected. As a rule, they are from three to five -feet in length, and from five-eighths to three-quarters of an inch in -diameter; at the upper end they branch out as shown in fig. 19. - -In conjunction with this terminal rod a short description of the -‘Auffangstange,’ or ‘reception rod’ of the Germans, may be given. -This ‘reception rod’ (see fig. 21) is made of iron, and varies in -length from ten to thirty feet. It consists of two parts, the higher -part, which measures two-thirds of the whole length, is fastened by a -flange to the lower part of the rod. In fixing this German ‘reception -rod,’ its height and weight have to be taken into consideration. It is -generally made fast by two strong staples, _b_ and _c_, as shown in -fig. 20, which pass through the king post of the roof and are fastened -behind by screw-nuts. The part marked _d_ rests in the lower ring _c_ -so that it cannot sink, and the extreme end passes through this ring -_c_ and is screwed tightly to the nut _e_; _f_ is a cap to prevent the -rain getting into the roof. - -It is much to be regretted that not only professors and amateurs -studying the manifestations of the electric force, but even learned -societies, such as the French ‘Académie des Sciences,’ should have -spread so many imaginative theories about this ‘reception rod.’ At the -bottom of all was the fancy, not often declared, but still visible in -its expression, of the metallic conductor possessing some occult power -of _attracting_ lightning. In France, as well as in Germany and Italy, -there existed for a long time, and to some extent still exists, quite -a mania for erecting huge rods, such as that shown in the engraving -(see fig. 21), on the top of buildings, the general belief being that -the more high-towering the greater would be the ‘area of protection.’ A -little common sense, brought to the aid of fanciful imaginings, should -have taught the supporters of this ‘area-of-protection’ theory that -it was absolutely untenable. The electric force, seeking its nearest -path to the earth, could not be expected to diverge from it through the -action of a rod raised somewhat higher than the surrounding building; -and the proper method clearly was to bring the metal everywhere as -near to any possible emanation of the force, whether lateral or -vertical, as could be done. Besides being really of no use, except -in rare instances, such as the neighbourhood of high trees, these -tall rods formerly employed, and still frequently seen on the roofs of -buildings, had the detriment of being unsightly, while at times they -were positively dangerous. Instances occurred in which a high wind -threw them down from their elevated position into the road below, on -the heads of passers-by. Thus two persons were killed in Paris in the -summer of 1830 by the fall of a gigantic ‘tige’ from the steeple of -the church of St. Gervais. Either at the same moment, or immediately -before, a stroke of lightning fell upon the church in its lower part, -away from the conductor, making a hole in one of the walls, and then -escaping, without doing further damage, by some iron water-pipes -running underground. The conductor in this case had been constructed -on the model approved by the ‘Académie des Sciences,’ but the accident -conclusively showed that there was no trust to be placed in any mere -theoretical calculations as to the extent of the ‘area of protection.’ - -A noteworthy example of the fallacy of the ‘area-of-protection’ theory -is to be found in the case of the explosion at the powder magazine -at the Victoria Colliery, BurntclifFe, Yorkshire, which was struck -by lightning and destroyed on August 6, 1878. The instance is also -instructive as showing how important it is that copper conductors -should possess the highest possible conductivity--i.e. be made of the -best and purest copper. - -The magazine was an oblong building of brick, nine feet long, five feet -wide, and six feet high (internal dimensions), and it had a uniform -thickness of three bricks. At one end was a heavy iron door, and at -the other a lightning conductor, consisting of a copper-wire rope -seven-sixteenths of an inch in diameter. The point of the terminal rod -was about thirteen feet above the top of the building, and a similar -length was carried into the ground and terminated in clayey soil. The -conductor was fixed to a pole distant about two inches from the end of -the building opposite to that in which the iron door was fixed. _It -was not connected with the iron door in any way._ At the time of the -explosion the magazine contained about 2,000 pounds of gunpowder. - -Major Majendie, H.M.’s Chief Inspector of Explosives, in his official -report ascribed the accident to the fact of the iron door being -unconnected with the lightning conductor, and in doing this he was -doubtless right, but only to a limited extent. The author of this work -visited the colliery shortly after the explosion, and found that the -conductor--the weight of which was about one pound per yard--had been -fastened to the pole, which was about twenty-one feet high, by two -glass insulators, and that the conductor was not connected with the -building. On testing the copper rope which formed the conductor, its -conductivity was found to be only 39·2 instead of 93 or 94 per cent. -The conductor, therefore, was but little better than if it had been -made of iron, and, even supposing it had been made of good copper, it -was of too small a size. It should have been of double the weight, and -_not_ insulated from the pole. In order to be thoroughly efficient it -ought to have been brought down the pole, carried through under the -roof, down the iron doorpost, and so into the ground. - -According to the French theory, that the ‘area of protection’ afforded -by a lightning conductor is the space contained within the circular -area of a radius double the height of the conductor, the magazine was -thoroughly secured, for the conductor was twenty-one feet high, and the -building only nine feet long, five feet broad, and six feet high. This -case, however, with many others, entirely controverts this theory, and -shows very forcibly the fallacy of an argument that at one time was -accepted almost as an axiom. - -One other case of more recent date may be instanced. At Cromer, in -Norfolk, the church--a fine perpendicular building of flint and -freestone, having a tower 159 feet high--was damaged by lightning in -August 1879. During a thunderstorm the lightning struck one of the -pinnacles with considerable force, although on another pinnacle, only -twenty-seven feet six inches distant, a good copper conductor, having -a diameter of five-eighths of an inch, was fixed. On testing the -conductor by means of a galvanometer, it and the earth connection were -found to be in thoroughly good order. After what has been said, comment -on this last example is needless. - -[Illustration: Fig. 22.] - -The general disposition and adjustment of a lightning conductor demands -the greatest care and consideration. No hard and fast rules can be -laid down, for each individual case must be studied and elaborated by -itself, especially in the instance of large structures, where much -depends upon style, outline, and other details. The main point is that -_every_ part of the building shall be placed beyond the possibility of -being damaged by a disruptive discharge of electricity. - -It has been stated previously that the lightning invariably follows -the line of least resistance, and that this line may be influenced by -the presence of streams of warm vapour, columns of smoke, &c., which, -escaping into the air, furnish a ready path for the electric discharge. -Consequently it sometimes happens that a building or barn may be struck -although it be provided with a lightning conductor. In order to -explain this it must be borne in mind that the line of least resistance -is not always the shortest line mathematically. The accompanying -illustration (fig. 22) is an example to the point. It represents a barn -furnished with a lightning conductor and filled with new-made hay, -which is a better conductor of electricity than the material of which -the barn is constructed. This hay is giving off the stream of warm -vapour which is pouring out of the opening at the end, and forms an -invisible band of conducting matter between the thunder-cloud and the -barn, as marked out in the engraving by the dotted lines, the direction -of the wind being shown by the arrow and the trees. Under these -circumstances the discharge of lightning would naturally follow the -path between _c_ and _d_ in preference to the shorter route between _a_ -and _b_, because the former is the line of least resistance between the -cloud and the earth. Thus the barn--although furnished with a conductor -in good condition--would most likely be set on fire, or otherwise -damaged. The same deflection of the lightning-stroke might be caused by -a column of smoke, or by the fact of one portion of the building being -moistened by the rain and the other kept dry; an occurrence that might -easily happen when a strong wind is blowing during a storm. - -In order to ensure complete protection, the conductor on the barn -should have been carried along the ridge and down the edges of the roof -at each gable. By this means the stroke of lightning would have been -intercepted. - -The engraving on the next page shows a design for the protection of a -large detached mansion by means of a multiplication of short points -or terminal rods fixed on all the prominent features of the building. -The conductor is carried along the ridges in every direction, and down -the edges of the roof at each gable. Generally it is sufficient to -have two descending conductors, but occasionally the conformation of -the building or the nature of the ground renders necessary the use of -even more. It is imperative, for obvious reasons, that the descending -portion of the lightning conductor shall be carried from the roof -to the ground by the shortest possible route, and placed in perfect -electrical contact with the earth in the manner to be indicated in a -succeeding chapter. - -[Illustration: Fig. 23.] - -The projecting points of the conductor are drawn in fig. 23 larger -than they need be, in order to show them more clearly, distinguishing -them from the rest of the building. The same has been done with the -copper rod, running from the roof to the ground and thence into the -earth. In reality a conductor may be made perfectly safe, and yet -all but invisible to the naked eye. For private houses and buildings, -a rope made of copper ought to be at least five-eighths of an inch -in diameter, for a copper rod of half an inch in diameter has never -been known to be fused. For chimneys of manufactories, where gases are -liable to corrode the rope, it had better be a little thicker. Such -copper ropes as those manufactured by Messrs. R. S. Newall and Co., -five-eighths of an inch in diameter, weighing two-thirds of a pound -per foot, and having a conductivity of 93 per cent., have never been -known to fail in protecting even the largest buildings. It is supposed -by some writers that the value of the conductor is in proportion to -the amount of surface of metal exposed. This, however, is a mistake, -for the conductivity depends on the weight per foot of metal used, the -purity in both being equal. Wire-rope is used simply because it is -so pliable that it is easily handled, and can be made of any length -required without joints. - -[Illustration: Fig. 24.] - -In fig. 24 is given an illustration of a small detached house, in which -the arrangement of the lightning conductor is indicated by the dark -lines. The method followed is exactly the same in principle as that -employed for the mansion just described. A terminal rod is placed upon -each chimney. These terminal rods are connected with each other by a -copper-rope conductor which is carried along the ridges and gables -of the roof, thus constituting a similar arrangement to the French -‘ridge-circuit’ (_circuit des faîtes_), with the additional advantage -of being far lighter and more sightly. The copper conductor descends -to the earth down the angle formed by the projecting entrance to the -house. By this means every corner of the building is protected; an -important matter in all detached buildings, and especially when they -happen to stand among trees. The preference of the electric force for -trees as its path to the earth in the absence of metal or other bodies -of higher conductivity than trees, has probably no other ground than -their being full of moisture; still this is a disputed question. - -Fig. 25 exhibits a slightly different method of arranging the lightning -conductor. In this case the ridges of the roof are surmounted by -ornamental iron-work, instead of the usual terra-cotta, or earthenware, -tiles. This iron-work is utilised and carefully connected with the -conductor. The chimneys, in place of being fitted with terminal rods, -are provided with cast-iron caps--as shown in the engraving--to which -the conductor is attached. The conductor, after descending to the -ridge, is led along it and down the edges of every gable, and is -finally carried down to the ground and connected with the earth in the -usual manner. It is of course absolutely necessary that all masses of -metal, such as gutters, waterspouts, rain-pipes, &c., should be brought -into connection with each other and with the conductor, in order that -the house may constitute one electrically homogeneous body. - -It was for a long time held that the protection of churches against -lightning offered special difficulties. This arose mainly from the -constant reports of churches being struck, often when they were -believed to be protected, whereas the accidents arose from the -conductor not being properly fitted. It is even now too often -forgotten that all so-called ‘conductors’ of the electric force are -only so in relation to ‘non-conductors,’ and that, strictly speaking, -all things on earth are to some extent conductors and to some extent -non-conductors. This being kept clearly in view, there is no more -difficulty in protecting the largest cathedral against lightning in the -most efficient manner than in similarly guarding the smallest cottage. - -[Illustration: Fig. 25.] - -A case in point occurred in May 1879. The steeple of the church at -Laughton-en-le-Morthen was struck by lightning and damaged, the -lightning conductor being thrown down and broken into two pieces. A -correspondence on the subject ensued in the _Times_, and Mr. R. S. -Newall had the remains of the conductor examined, with the following -result: - -‘The spire is 175 feet in height, and it had attached to it a thin -tube, made of corrugated copper, about seven-eighths of an inch in -external diameter and five-eighths internal. The copper is about -one-thirty-second of an inch in thickness, and it weighs about one and -a quarter pound per yard. It is made in short lengths, joined together -by screws and coupling pieces, but there is no metallic contact -whatever between the pieces, which are much corroded. - -‘The conductor appeared to be fastened to the vane. It was not in -contact with the building, which it ought to have been, but it was kept -at a distance of about two-and-a-half inches from it by twenty-one -insulators. The earth contact was obtained by bending the tube and -burying it in the ground at a depth of from six inches to eighteen -inches, the soil being dry loose rubbish; the length of the earth end -was only three feet, with two short pieces of about a foot in length -each tied to the tube by thin wires, thus forming altogether a most -inefficient conductor. It was placed in a corner formed by a double -stone buttress, which came between the conductor and a lead-covered -roof attached to the spire, the distance between the conductor and the -lead roof being about six feet six inches. - -‘The lightning appears to have come down the conductor a certain -distance, and, finding the road to earth bad, it passed through the -buttress, dislodging about two cart-loads of stone, and then came down -the cast-iron down pipes leading from the lead-covered roof and so to -earth.’ - -Mr. Newall, in writing to the _Times_, goes on to say:— - -‘Now if the conductor had been made of copper-wire rope, weighing about -two pounds per yard, and fixed in contact with the spire, without -insulators and with a proper earth contact, no damage whatever would -have been sustained by the building; and if the conductor had been -tested periodically by an expert he would have shown whether the -conductor was good or useless. This examination ought to be insisted -on, as the earth connection is often wilfully destroyed; but I have -never in all my experience known a building which had a conductor -properly fixed to suffer damage from lightning.’ - -What is really required is to make a lightning conductor of sufficient -calibre to carry down the electric discharge, however great it may be, -from the summit of the building into the earth, and that the earth -contact should be above suspicion and thoroughly good in all seasons. - -[Illustration: Fig. 26.] - -[Illustration: Fig. 27.] - -[Illustration: Fig. 28.] - -Fig. 26 shows a plain and simple design for protecting an ordinary -church. The conductor in the case of churches and all other high or -extensive buildings ought invariably to be made of copper rope, other -metals of less conductivity, such as iron, being inadmissible, since -their employment would necessitate the use of ponderous masses of -metal, which would be not only unsightly, but extremely heavy, and -difficult to manipulate successfully. In the accompanying engraving -(fig. 27) lent by the Society for Promoting Christian Knowledge, is -shown a somewhat more complex structure and the method of arranging -the conductors thereon. In this case there is a conductor attached to -each spire, leading to and connected with the metal-work of the roof -and gutters. On the gable _c_, and the transept gables _d e_, there -are fixed three conductors which unite in the centre of the roof, from -which they are carried down to the gutters. The same arrangement is -followed for the smaller gables _f g h_. The water-pipes and gutters -being connected with the conductors, these latter are carried down the -side to the earth. It need scarcely be explained how important it is -that all metal ornaments on the ridges of churches, as well as other -buildings, should either be connected with the general conductors or, -in the case of extensive buildings, with a conductor that is carried -straight to the earth, as shown in fig. 28. In the case of the finials -so often found on Gothic structures, it is necessary to splice the -conductor round the bottom of the finial, as shown in fig. 29. If, -instead of placing terra-cotta tiles along the ridges, a cresting of -fancy iron-work is fixed there, the expense of running a conductor -along the ridges will be saved. - -[Illustration: Fig. 29.] - -[Illustration: Fig. 30.] - -The various methods of fixing weathercocks on to the terminal rod are -fully explained in another chapter. Fig. 30 shows the best arrangement -for connecting the conductor to the terminal rod on a church spire. The -copper rope which forms the conductor is spliced round the terminal -rod at the bottom of the finial, and as an additional security round -the base of the vane rod, which in this instance also serves as the -terminal rod of the lightning conductor. - -There has been much controversy as to whether it is better to carry -the conductor from the roof to the ground inside a building than -outside the walls. As a matter of fact, it is a question of very small -importance which way the conductor is carried, so long as it arrives -at the ground by the shortest possible route. Benjamin Franklin, to -judge from many expressions in his works, seems to have been decidedly -in favour of the inside plan, which was adopted almost universally in -France and on the Continent in general on the first introduction of -lightning conductors. But the method was soon abandoned, owing partly -to a witty saying of Voltaire, constantly quoted to this day. Speaking -of the death of the unfortunate Professor Richman, of St. Petersburg, -killed while experimenting with electric discharges from the clouds, -Voltaire remarked, ‘There are some great lords whom one should only -approach with extreme precaution: lightning is such a one.’ A mere -jocular exclamation, it would have had no great force except in France, -where a _bon mot_ may cause the fall of a king and the dethronement of -a dynasty. In regard to Voltaire’s pleasantry about not approaching -too close to lightning, it really had in great part the effect of -preventing conductors to be laid inside the houses. Even such calm -philosophers and men of science as Professor Arago quote Voltaire with -approval. ‘I feel inclined,’ he remarks in his ‘Meteorological Essays,’ -‘to admit that the illustrious author (Voltaire) may be right, when I -remember a case that occurred in the United States.’ The case relied -upon, a very curious one, was as follows, in Arago’s own words. - -‘Lightning,’ Professor Arago tells his story, ‘having struck a rather -thick rod erected on a Mr. Raven’s house, in Carolina, United States, -afterwards ran along a wire carried down the outside of the house to -connect the rod on the roof with an iron bar stuck in the ground. The -lightning in its descent melted all the part of the wire extending -from the roof to the ground-storey, without injuring in the least the -wall down which the wire was carried. But at a point intermediate -between the ceiling and the floor of the lower storey things were -changed: from thence to the ground the wire was not melted, and at -the spot where the fusion ceased the lightning altered its course -altogether, and, striking off at right angles, made a rather large -hole in the wall and entered the kitchen. The cause of this singular -divergence was readily perceived, when it was remarked that the hole -in the wall was precisely on a level with the upper part of the barrel -of a gun which had been left standing on the floor leaning against the -wall. The gun barrel was uninjured, but the trigger was broken, and a -little further on some damage was done in the fire-place.’ Commenting -upon this case, Professor Arago goes on: ‘Here the lightning went off -horizontally through the wall, in order to strike a fowling-piece -standing upright in the kitchen. How much injury might not have -resulted from this lateral movement, if the lightning had not had to -traverse a thick wall?’ Consequently, he argues, Voltaire is right in -his jocular-oracular declaration about the perils of indoor lightning -conductors, in their being ‘great lords’ dangerous to approach. - -It is really difficult to understand how a man like Professor Arago -could be misled into such false reasoning as this about an accident -which, in itself, was of the simplest, and of the very easiest -explanation. That the stroke of lightning falling upon Mr. Raven’s -house, in Carolina, should have melted the wire of the conductor -points to one cause, and to one only, namely, that there was no proper -earth connection. Had it existed, the wire, although thin, could not -possibly have been ‘melted all the part extending from the roof to the -ground-storey,’ nor could the electric force have left its appointed -path to seek a better one through a wall, and, still more astounding, -‘striking off at right angles.’ It is abundantly clear that such -cases, and others to the same effect, brought against the fixing of -lightning-conductors inside the walls of buildings, prove absolutely -nothing. What is beyond controversy is, that a good conductor, in -proper condition, is absolutely harmless to surrounding objects, -including human beings. A man, even with a ‘fowling-piece’ in his -hands, might lean full length against half-an-inch copper rod carrying -off a heavy stroke of lightning into ‘good earth’ without so much as -becoming aware of the passing of the electric discharge. If certainly a -‘grand seigneur,’ as Voltaire remarks, the electric force has this in -common with some of the greatest of men, of not wasting its time, but -following a clear aim. - -[Illustration: Fig. 31.] - -[Illustration: Fig. 32.] - -A very common, and, it may be added, a very mischievous opinion is -prevalent, that lightning conductors should be carefully insulated -from the buildings to which they are attached, and consequently many -conductors are made to pass through insulators of glass and other -materials of low conductivity. This practice of separating the building -from the lightning conductor is not only utterly useless but positively -dangerous. It is not unusually thought that by insulating the conductor -the electric discharge will be prevented from entering the building. -Such an idea is _ipso facto_ absurd, for it is preposterous to suppose -that a flash of lightning which can travel through thousands of feet of -air--itself a very bad conductor of electricity--and then shatter to -pieces the most compact bodies, would be stopped in its course by means -of a few inches of glass, or a few feet of air. It may therefore be -confidently asserted that no insulator can possibly be made that would -be capable of preventing the electric discharge leaving the lightning -conductor provided it could find an easier path leading to the earth. -Mr. Phin, in his work on ‘Lightning-Rods’ says very pertinently:--But -not only are insulators worthless--they are positively dangerous if -the principle upon which they are adopted is fully carried out, which, -however, is but rarely done. A little consideration will show this. -Thus, if a house be furnished with a carefully-insulated lightning-rod, -and should also have any large surface of metal, such as a tin roof, -an extensive system of gutters, or such like, connected with it, it -is easy to see that the house must resemble a large Leyden jar, of -which the tin roof, or other mass of metal, constitutes one coating, -and the lightning-rod and the earth constitute the other, while the -insulators and the dry material of the house represent the glass of the -jar. If both the outside and the inside of this jar (the tin roof and -the earth) had been connected together, it would have been impossible -to have brought one coating into a condition opposite to that of the -other. But the rod being carefully insulated from the roof, it is -obvious that the inductive action of the cloud will bring the roof -and the earth into opposite conditions; and if a man were to form the -path of least resistance between them, the discharge would take place -through his body, and he would probably be destroyed. It is obvious, -then, in the first place, that lightning-rods should be connected with -all large masses of metal which may exist in or upon the house, such -as metallic roofs, tin or iron gutters, or pipes, iron railings, &c. -In the second place, the rod should be attached to the house in the -neatest and least obtrusive manner possible.’ - -[Illustration: Fig. 33.] - -It is indeed desirable for various reasons that the copper rope or band -forming the lightning conductor should be affixed to the building in -the neatest and least obtrusive manner possible. The conductor may be -fastened by means of ordinary metal staples made of stout copper wire. -A better method however is indicated in figs. 31 and 32, one showing -the rope conductor formed of forty-nine wires, usually employed by -Messrs. R. S. Newall and Co. for the protection of ordinary houses -and buildings, and the other the copper band used by them for the -same purpose. This fastening is simply a strap of copper bent to the -required shape and pierced with two holes, by means of which it is -fixed to any building by copper nails or screws. This method possesses -several advantages; it is very sightly and neat, it can be easily -applied without injury to any building, and as it allows the conductor -a certain freedom of movement, it readily permits the contraction and -expansion caused by the variations of temperature. The band conductor -shown here is one inch wide by one-eighth of an inch thick, and weighs -·44 pound per foot. The rope conductor, although it appears less, has -more metal in it; it measures five-eighths of an inch in diameter, -and weighs ·67 pound. Fig. 33 shows a different mode of attaching the -lightning conductor. It is generally used for the heavier ropes. - -Fig. 34 exhibits an apparatus called a ‘tightening screw.’ It is used -for making the conductor taut when it gets loose from any cause. The -diagram explains itself, so there is no necessity for describing it. - -The tall chimney shafts of factories and similar buildings, from which -smoke or rarefied air escapes, are peculiarly liable to be struck by -lightning. This is principally due to the current of smoke or warmed -air forming, with the soot in the chimney, a medium conductor leading -to the iron-work of the furnace or stove beneath, but ending there--a -result that must be carefully avoided; for although a conductor that -leads past any object is a protection (provided always that it has a -good earth connection), a conductor that leads to an object, and ends -in that object, is a distinct danger. It is therefore necessary to -offer to the electric discharge a better conductor, able to intercept -it and convey it safely to earth on the outside of the shaft. - -[Illustration: Fig. 34.] - -[Illustration: Fig. 35.] - -The mode by which this is generally accomplished in England is by -fixing a copper terminal rod (four or five feet long), on to the side -of the top of the chimney shaft. This method is open to one serious -objection: if the wind should happen to blow the stream of smoke or -heated vapour in a direction opposite to the terminal rod, the electric -discharge might go down the chimney shaft and effect considerable -damage. By far the best plan is that shown in fig. 35. It consists -simply of an iron or copper cap, to the centre of which is attached -the terminal rod. This latter, however, is by no means essential, and -may be said to be merely placed on the top for ornament. A structure -of such small circumference really wants no terminal rod, the most -important thing being to provide a copper rope or band conductor of -sufficient size to carry any electric discharge in safety to the -ground. It will conduce greatly to the strength and stability of such -a conductor if it be built up together with the chimney shaft, and -fastened into the brickwork by clamps on the plan shown in fig. 36. A -conductor of this kind should be made of copper rope or band of much -greater calibre and weight than that used for ordinary buildings. That -made of seven solid wires twisted together (see fig. 37) being the best. - -[Illustration: Fig. 36.] - -A theory propounded some years ago by the late Prof. Clerk Maxwell, -F.R.S., one of the most eminent physicists in Europe, deserves some -notice here, perhaps more from its ingenuity than its practical -accuracy. On investigation, it proves to be a revival of an old -presumption that it is possible to protect a powder magazine or other -building from the effects of lightning by having its roof, walls, and -ground floor surrounded with a covering of sheet metal, or a network of -lightning conductors, and disconnecting the said covering or network -from the earth, or even insulating it by means of a layer of asphalt or -some similar substance. Prof. Clerk Maxwell argues that the presence of -a lightning conductor induces a larger number of electric discharges -in its immediate neighbourhood than would occur provided no conductor -was present, although at the same time these discharges are rendered -less intense and smaller by reason of the existence of the conductor. -Therefore, it is possible that fewer discharges take place in the area -just outside the radius of the conductor. Reasoning from this, Prof. -Clerk Maxwell considers that an ordinary lightning conductor tends -rather to mitigate the accumulation of electricity in the clouds than -to protect the building on which it is placed. - -[Illustration: Fig. 37.] - -He says: ‘What we really wish to prevent is the possibility of an -electric discharge taking place within a certain region--say, in the -inside of a gunpowder manufactory. If this is clearly laid down as our -object, the method of securing it is equally clear. - -‘An electric discharge cannot occur between two bodies unless the -difference of their potentials (i.e. their electrical conditions) -is sufficiently great, compared with the distance between them. If, -therefore, we can keep the potentials of all bodies within a certain -region equal, or nearly equal, no discharge will take place between -them. We may secure this by connecting all these bodies by means of -good conductors, such as copper wire ropes, but it is not necessary -to do so, for it may be shown by experiment that if every part of the -surface surrounding a certain region is at the same potential, every -point within that region must be at the same potential, provided no -charged body is placed within the region. - -‘It would therefore be sufficient to surround our powder-mill with a -conducting material, to sheath its roof, walls, and ground-floor with -thick sheet-copper, and then no electrical effect could occur within -it on account of any thunderstorm outside. There would be no need of -any earth connection. We might even place a layer of asphalt between -the copper floor and the ground, so as to insulate the building. If -the mill were then struck with lightning, it would remain charged for -some time, and a person standing on the ground outside and touching the -wall might receive a shock, but no electrical effect would be perceived -inside, even on the most delicate electrometer. The potential of -everything inside with respect to the earth would be suddenly raised or -lowered as the case might be; but electric potential is not a physical -condition, but only a mathematical conception, so that no physical -effect would be perceived. - -‘It is therefore not necessary to connect large masses of metal, such -as engines, tanks, &c., to the walls, if they are entirely within the -building. If, however, any conductor, such as a telegraph-wire, or a -metallic supply-pipe for water or gas, comes into the building from -without, the potential of this conductor may be different from that -of the building, unless it is connected with the conducting shell of -the building. Hence the water or gas supply-pipes, if any enter the -building, must be connected to the system of lightning conductors; and -since to connect a telegraph-wire with the conductor would render the -telegraph useless, no telegraph from without should be allowed to enter -a powder-mill, though there may be electric bells and other telegraphic -apparatus within the building. I have supposed the powder-mill to -be entirely sheathed in thick sheet copper. This, however, is by no -means necessary in order to prevent any sensible electrical effect -taking place within it, supposing it struck by lightning. It is quite -sufficient to enclose the building with a network of a good conducting -substance. For instance, if a copper wire, say No. 4, B. W. G. (0·238 -inch diameter) were carried round the foundation of the house, up each -of the corners and gables, and along the ridges, this would probably -be a sufficient protection for an ordinary building against any -thunderstorm in this climate. The copper wire may be built into the -wall to prevent theft, but should be connected to any outside metal, -such as lead or zinc on the roof, and to metal rain-water pipes. In the -case of a powder-mill, it might be advisable to make the network closer -by carrying one or two additional wires over the roof and down the -walls to the wire of the foundation. If there are water or gas-pipes -which enter the building from without, these must be connected with -the system of conducting wires; but if there are no such metallic -connections with distant points, it is not necessary to take any pains -to facilitate the escape of the electricity into the earth; still less -is it advisable to erect a tall conductor with a sharp point in order -to relieve the thunder-clouds of their charge. - -[Illustration: Fig. 38. ARRANGEMENT OF PROFESSOR CLERK MAXWELL’S -LIGHTNING CONDUCTORS.] - -‘It is hardly necessary to add, that it is not advisable, during a -thunderstorm, to stand on the roof of a house so protected, or to stand -on the ground outside, and lean against the wall.’ - -Prof. Clerk Maxwell, in a letter to Mr. Charles Tomlinson, F.R.S., the -author of ‘The Thunderstorm,’ says: ‘My plan is to convert a building -into a closed conducting vessel by a sufficient number of wires -enclosing it. For an ordinary house, a skeleton of its edge is quite -enough. A _a_ may be a zinc ridge, B _b_ and C _c_ water-gutters of -zinc or iron; but the pieces A B D, A C E, _a b d_, _a c e_, and the -circuit D E _e d_ should be of stout copper wire or rope, built into -the wall as a security against theft, but connected to every other -piece of metal on the outer surface of the house, and to every gas or -water-pipe which enters the house from without, but _not_ to any masses -of metal wholly within the whole, unless this is desirable for other -purposes.’ - -[Illustration: Fig. 39.] - - - - -CHAPTER XIV. - -ACCIDENTS AND FATALITIES FROM LIGHTNING. - - -The accidents that occur annually from the effects of lightning are -far greater in number and extent than is generally supposed. Although -the art of protecting buildings by means of lightning conductors was -discovered some hundred and twenty-seven years ago, and it is now one -hundred and eleven years since, in 1768, Benjamin Franklin’s ‘lightning -rods’ were first set up over the dome of Saint Paul’s Cathedral, yet -the application of this great discovery is by no means general. At -least one-half, and perhaps two-thirds, of all the public buildings, -including the churches and chapels, of Great Britain and Ireland, -are without any protection against lightning. As to private houses, -it may safely be affirmed that not five out of every thousand are -fitted with lightning conductors. It is well known that the amount of -property annually destroyed by lightning in this country is very great, -though it is, very naturally, impossible to form any accurate, or even -approximate estimate of it. With regard, however, to the number of -deaths from the same cause, certain statistics do exist, although many -of them are notoriously imperfect. According to the ‘Fortieth Report of -the Registrar-General,’ issued in July 1878, and former reports, the -number of deaths from lightning in England and Wales was as follows in -each of the nine years from 1869 to 1877:— - - +--------+-------+---------+-------+ - | Years | Males | Females | Total | - +--------+-------+---------+-------+ - | 1869 | 5 | 2 | 7 | - | 1870 | 13 | 6 | 19 | - | 1871 | 23 | 5 | 28 | - | 1872 | 35 | 11 | 46 | - | 1873 | 17 | 4 | 21 | - | 1874 | 25 | — | 25 | - | 1875 | 14 | 3 | 17 | - | 1876 | 15 | 4 | 19 | - | 1877 | — | — | 12 | - +--------+-------+---------+-------+ - | Total | 147 | 35 | 194 | - +--------+-------+---------+-------+ - -The official returns of the number of deaths from lightning, as given -by the English Registrar-General, are admittedly incomplete. In -Prussia, where the registration of the causes of death is most rigidly -enforced by law, and, in consequence, is far more accurate than in -England, there were one thousand and four persons reported as killed -by lightning in the nine years from 1869 to 1877. According to the -official report issued by Dr. Ernst Engel, Director of the Statistical -Bureau of Berlin, the number of lives lost each year was as follows:— - - +--------+-------+---------+-------+ - | Years | Males | Females | Total | - +--------+-------+---------+-------+ - | 1869 | 47 | 32 | 79 | - | 1870 | 59 | 43 | 102 | - | 1871 | 56 | 47 | 103 | - | 1872 | 50 | 35 | 85 | - | 1873 | 61 | 50 | 111 | - | 1874 | 58 | 49 | 107 | - | 1875 | 92 | 48 | 140 | - | 1876 | 59 | 47 | 106 | - | 1877 | 105 | 66 | 171 | - +--------+-------+---------+-------+ - | Total | 587 | 417 | 1,004 | - +--------+-------+---------+-------+ - -The population of Prussia is somewhat larger than that of England -and Wales--25¾ millions against 24½ millions--but on the other hand, -thunderstorms are less frequent there than with us. Altogether it will -be rather under than over the mark to say that as many persons are -killed by lightning in England as in Prussia, the loss amounting, on -the average, to over one hundred every year. - -Of the deaths by lightning in France, Mons. Boudin some years ago -collected statistics which showed that during the thirty years -beginning in 1834 and ending in 1863, two thousand and thirty-eight -people were struck dead by lightning in that country. During the last -ten years of this period, the deaths amounted to eight hundred and -eighty, and of these only two hundred and forty-three were females. -In connection with this it is a noticeable fact that when a lightning -stroke falls upon a crowd, it almost invariably causes more fatalities -among the men than the women. - -In the following tables are given statistics of deaths and accidents -from lightning in the various countries referred to. - -In the case of the United States, the Chief of the Bureau of Statistics -writes that no record of deaths or fires caused by lightning is -kept--a somewhat curious admission on the part of such a practical -and methodical country. A similar reply has been received from the -authorities in Spain. - - - CAS DE MORT, OCCASIONNÉS PAR LA FOUDRE, DANS LES 49 GOUVERNEMENTS - DE LA RUSSIE EUROPÉENNE, SANS COMPTER LA FINLANDE ET LES - GOUVERNEMENTS DU CI-DEVANT ROYAUME DE POLOGNE. - - +--------------------------------+--------+--------+ - | ANNÉES | HOMMES | FEMMES | - +--------------------------------+--------+--------+ - | 1870 | 261 | 139 | - | 1871 | 260 | 167 | - | 1872 | 404 | 216 | - | 1873 | 300 | 179 | - | 1874 | 227 | 117 | - +--------------------------------+--------+--------+ - | Total (en cinq années) | 1,452 | 818 | - | De ce nombre dans les villes | 75 | 34 | - | De ce nombre dans les villages | 1,377 | 784 | - +--------------------------------+--------+--------+ - - - INCENDIES, OCCASIONNÉS PAR LA FOUDRE, DANS LES 49 GOUVERNEMENTS - DE LA RUSSIE EUROPÉENNE, SANS COMPTER LA FINLANDE ET LES - GOUVERNEMENTS DU CI-DEVANT ROYAUME DE POLOGNE. - - +--------+-----------------+-------------------+ - | ANNÉES | DANS LES VILLES | DANS LES VILLAGES | - +--------+-----------------+-------------------+ - | 1870 | 11 | 571 | - | 1871 | 23 | 767 | - | 1872 | 28 | 1,217 | - | 1873 | 19 | 908 | - | 1874 | 12 | 636 | - +--------+-----------------+-------------------+ - | Total | 93 | 4,099 | - +--------+-----------------+-------------------+ - - Dans le gouvernement de Cherson les villes Odessa et Nicolaev ne - sont pas comprises, à cause du manque de renseignements. - -The returns from Russia, which include the years 1870, 1871, 1872, -1873, and 1874, are here printed as they were received from the -President of the Commission for Statistics at St. Petersburg. - -The returns from Sweden, extending as they do over a period of more -than sixty years, are highly interesting. In this case the difference -in the number of men and women killed is not so noticeable as in other -countries:— - - -DEATHS BY LIGHTNING IN SWEDEN. - - +------+------+------------------------------------------------------+ - | | | Of which | - | Year | Total|----------+----------+------+--------+--------+-------+ - | | | Under 10 | Over 10 | | | In the | In the| - | | | years old| years old| Males| Females| country| towns | - +------+------+----------+----------+------+--------+--------+-------+ - | 1877 | 8 | — | 8 | 4 | 4 | 7 | 1 | - | 1876 | 14 | 2 | 12 | 6 | 8 | 14 | — | - | 1875 | 16 | — | 16 | 10 | 6 | 16 | — | - | 1874 | 9 | — | 9 | 6 | 3 | 9 | — | - | 1873 | 14 | 1 | 13 | 7 | 7 | 13 | 1 | - | 1872 | 26 | 2 | 24 | 10 | 16 | 25 | 1 | - | 1871 | 6 | — | 6 | 2 | 4 | 5 | 1 | - | 1870 | 9 | 1 | 8 | 5 | 4 | 9 | — | - | 1869 | 7 | 1 | 6 | 3 | 4 | 7 | — | - | 1868 | 14 | — | 14 | 11 | 3 | 14 | — | - | 1867 | 5 | — | 5 | 3 | 2 | 5 | — | - | 1866 | 26 | 2 | 24 | 8 | 18 | 25 | 1 | - | 1865 | 13 | 2 | 11 | 7 | 6 | 13 | — | - | 1864 | 5 | 1 | 4 | 2 | 3 | 4 | 1 | - | 1863 | 4 | — | 4 | 3 | 1 | 4 | — | - | 1862 | 12 | 2 | 10 | 10 | 2 | 11 | 1 | - | 1861 | 15 | — | — | — | — | 15 | — | - | 1860 | 7 | — | — | 4 | 3 | 7 | — | - | 1859 | 22 | 4 | 18 | 12 | 10 | 20 | 2 | - | 1858 | 18 | — | 18 | 11 | 7 | 17 | 1 | - | 1857 | 6 | 1 | 5 | 3 | 3 | 6 | — | - | 1856 | 6 | 1 | 5 | 3 | 3 | 6 | — | - | 1855 | 25 | 2 | 23 | 16 | 9 | 25 | — | - | 1854 | 5 | — | 5 | 4 | 1 | 5 | — | - | 1853 | 8 | 1 | 7 | 4 | 4 | 8 | — | - | 1852 | 15 | 4 | 11 | 7 | 8 | 14 | 1 | - | 1851 | 9 | — | 9 | 7 | 2 | 9 | — | - | 1850 | 9 | 3 | 6 | 6 | 3 | 9 | — | - | 1849 | 11 | 1 | 10 | 4 | 7 | 10 | 1 | - | 1848 | 5 | — | 5 | 1 | 4 | 5 | — | - | 1847 | 10 | — | 10 | 3 | 7 | 10 | — | - | 1846 | 21 | 1 | 20 | 14 | 7 | 21 | — | - | 1845 | 16 | 4 | 12 | 10 | 6 | 14 | 2 | - | 1844 | 11 | — | 11 | 9 | 2 | 10 | 1 | - | 1843 | 2 | — | 2 | — | 2 | 2 | — | - | 1842 | 7 | 1 | 6 | 5 | 2 | 7 | — | - | 1841 | 7 | 1 | 6 | 5 | 2 | 7 | — | - | 1840 | 2 | — | 2 | 1 | 1 | 2 | — | - | 1839 | 22 | 4 | 18 | 17 | 5 | 22 | — | - | 1838 | 11 | 1 | 10 | 9 | 2 | 11 | — | - | 1837 | 5 | 2 | 3 | 3 | 2 | 5 | — | - | 1836 | 4 | — | 4 | 2 | 2 | 4 | — | - | 1835 | 5 | 1 | 4 | 3 | 2 | 5 | — | - | 1834 | 36 | 4 | 32 | 21 | 15 | 36 | — | - | 1833 | 7 | 1 | 6 | 6 | 1 | 7 | — | - | 1832 | 5 | — | 5 | 1 | 4 | 5 | — | - | 1831 | 7 | 1 | 6 | 3 | 4 | 7 | — | - | 1830 | 5 | — | — | 5 | — | — | — | - | 1829 | 10 | — | — | 6 | 4 | — | — | - | 1828 | 9 | — | — | 6 | 3 | — | — | - | 1827 | 5 | — | — | 4 | 1 | — | — | - | 1826 | 11 | — | — | 6 | 5 | — | — | - | 1825 | 6 | — | — | 3 | 3 | — | — | - | 1824 | 6 | — | — | 4 | 2 | — | — | - | 1823 | 5 | — | — | 3 | 2 | — | — | - | 1822 | 8 | — | — | 4 | 4 | — | — | - | 1821 | 4 | — | — | 3 | 1 | — | — | - | 1820 | 15 | — | — | 8 | 7 | — | — | - | 1819 | 32 | — | — | 17 | 15 | — | — | - | 1818 | 10 | — | — | 4 | 6 | — | — | - | 1817 | 4 | — | — | 2 | 2 | — | — | - | 1816 | 7 | — | — | 3 | 4 | — | — | - +------+------+----------+----------+------+--------+--------+-------+ - - -DEATHS BY LIGHTNING IN BADEN. - - +-------+-------+----------+-------+ - | Year | Males | Females | Total | - +-------+-------+----------+-------+ - | 1874 | 3 | — | 3 | - | 1875 | 3 | 5 | 8 | - | 1876 | 2 | 7 | 9 | - +-------+-------+----------+-------+ - | Total | 8 | 12 | 20 | - +-------+-------+----------+-------+ - - -FIRES THROUGH LIGHTNING IN BAVARIA. - -_Right side of Rhine._ - - +---------+-------+ - | Year | Total | - +---------+-------+ - | 1843–44 | 24 | - | 1844–45 | 39 | - | 1845–46 | 54 | - | 1846–47 | 25 | - | 1847–48 | 27 | - | 1848–49 | 26 | - | 1849–50 | 30 | - | 1850–51 | 32 | - | 1851–52 | 44 | - | 1852–53 | 60 | - | 1853–54 | 38 | - | 1854–55 | 47 | - | 1855–56 | 70 | - | 1856–57 | 66 | - | 1857–58 | 56 | - | 1858–59 | 60 | - | 1859–60 | 50 | - | 1860–61 | 64 | - | 1861–62 | 63 | - | 1862–63 | 80 | - | 1863–64 | 59 | - | 1864–65 | 90 | - | 1865–66 | 48 | - | 1866–67 | 100 | - | 1867–68 | 140 | - | 1868–69 | 86 | - | 1869–70 | 79 | - | 1870–71 | 115 | - | 1871–72 | 107 | - | 1872–73 | 170 | - +---------+-------+ - - -_Left side of Rhine._ - - Year Total - 1870 6 - 1873 36 - - -AUSTRIA. LIST OF DAMAGES BY FIRE THROUGH LIGHTNING. - - Key: - AWE - Austria, Western Europe - AEE - Austria, Eastern Europe - Sa. - Salzburg - St. - Styria - K. - Kärnten - Il. - Illyria - Co. - Coastland - Ty. - Tyrol - Bo. - Bohemia - Mä. - Mähren - Si. - Silesia - Ga. - Galicia - Bu. - Buckovina - D. - Dalmatia - +-----+------+-----------------------------------------------------------+ - | | | Of which those through lightning are:— | - |Year |Total +---+---+---+---+--+---+---+---+---+---+---+---+---+--+-----+ - | |Fires |AWE|AEE|Sa.|St.|K.|Il.|Co.|Ty.|Bo.|Mä.|Si.|Ga.|Bu.|D.|Total| - +-----+------+---+---+---+---+--+---+---+---+---+---+---+---+---+--+-----+ - |1870 | 4,171| 20| 16| 1| 14| 3| 4| 2| 2| 58| 15| —| 26| —| —| 161| - |1871 | 4,293| 9| 26| 1| 9| 5| 2| 3| 1| 53| 8| 1| 34| 4| —| 156| - |1872 | 5,265| 11| 26| 4| 32| 5| 12| 3| 2| 45| 14| 7| 56| 5| 1| 223| - |1873 | 5,500| 11| 16| 3| 30| 4| 12| 1| 11| 88| 18| 7| 42| 3| 3| 249| - |1874 | 5,244| 15| 24| —| 32| 5| 9| —| 8| 79| 15| 5| 53| 5| —| 250| - |1875 | 4,529| 17| 34| —| 19| 4| 10| 2| 7| 68| 19| 8| 62| —| —| 250| - |1876 | 5,001| 18| 13| 1| 22| 5| 5| 1| 1| 59| 15| —| 48| —| —| 188| - |1877 | 6,125| 21| 23| 3| 23| 8| 8| —| 7| 63| 19| 6| 43| 1| —| 225| - +-----+------+---+---+---+---+--+---+---+---+---+---+---+---+---+--+-----+ - |Total|40,128|122|178| 13|181|39| 62| 12| 39|513|123| 34|364| 18| 4| 1702| - +-----+------+---+---+---+---+--+---+---+---+---+---+---+---+---+--+-----+ - - -DEATHS BY LIGHTNING IN WURTEMBERG. - - Year Total - 1841–42 26 - 1851–60 117 - - -DEATHS BY LIGHTNING IN SWITZERLAND. - - +-------+-------+---------+-------+ - | | Males | Females | Total | - +-------+-------+---------+-------+ - | 1876 | 2 | 1 | 3 | - | 1877 | 21 | 9 | 30 | - +-------+-------+---------+-------+ - | Total | 23 | 10 | 33 | - +-------+-------+---------+-------+ - -The data given here is necessarily incomplete, although much trouble -has been taken in obtaining it. Many countries keep no separate records -of deaths and accidents from lightning, and those kept by others -are often meagre and untrustworthy. Still the statistics given are -sufficient to prove that lightning constitutes no unimportant factor -among the dangers that threaten the safety of human life. The apathy -with which the danger is regarded by most people is simply astounding: -very few make any effort to protect themselves or their houses -against it, although during certain months of the year it is almost -impossible to take up a newspaper that does not contain an account -of some fatality or casualty from the effects of a thunderstorm. The -long roll of accidents appended to this chapter shows only too clearly -the enormous amount of damage that has arisen--and is continually -arising--from this source. Public buildings fare little better than -private houses. Even some of the first cathedrals of England have no -lightning conductors whatever, while others, supplied with them, are -insufficiently protected, as is apparent to any competent observer. A -glaring instance of the absence of protection against lightning is to -be found at Windsor Castle. It is a fact that several portions of this -splendid palace, among them St. George’s chapel, and the adjoining -Belfry Tower, are entirely unprovided with lightning conductors. On -other parts of the castle a few conductors are placed, but clearly -not enough. It is needless to say that, speaking only of St. George’s -chapel and the Belfry Tower, these beautiful buildings, constantly -touched by the storm-clouds that sweep up the valley of the Thames, are -liable at any moment to destruction or great damage. - -Thomas Fuller, in his ‘Church History of Britain,’ states that-- - -‘There was scarce a great abbey in England which (once, at the least) -was not burnt down with lightning from Heaven. 1. The Monastery of -Canterbury, burnt anno 1145, and afterwards again burnt anno 1174. 2. -The abbey of Croyland, twice burnt. 3. The Abbey of Peterboro, twice -set on fire. 4. The Abbey of Mary’s in York, burnt. 5. The Abbey of -Norwich, burnt. 6. The Abbey of St. Edmondsbury, burnt and destroyed. -7. The Abbey of Worcester, burnt. 8. The Abbey of Gloucester. 9. The -Abbey of Chichester, burnt. 10. The Abbey of Glastonbury, burnt. 11. -The Abbey of St. Mary in Southwark, burnt. 12. The Church of the Abbey -of Beverley, burnt. 13. The steeple of the Abbey of Evesham, burnt.’ - -Even in those cases where in modern times lightning conductors have -been applied to buildings, they are very often improperly fixed in -the first instance, or, having once been put up, are never examined -or tested with the view of ascertaining their constant efficiency. -Several accidents owing their origin to one or the other of these -causes have occurred quite recently. In May 1879, the church at -Laughton-en-le-Morthen was struck by lightning and damaged in the -manner described in Chapter XIII. The spire was fitted with a -corrugated copper tube conductor the joints of which were made by -screws and coupling-pieces, but there was no metallic contact between -the lengths; the conductor was insulated from the building; and the -earth-contact was obtained by bending the end of the tubing, and -inserting it about twelve inches deep in dry loose rubbish! Such a -conductor is worse than useless. If it had been examined by a competent -person, it must at once have been utterly condemned. In June 1879, -a disastrous result followed the use of a similar conductor erected -upon a private house near Sheffield. In this case the corrugated tube -forming the conductor contained too little metal, and it was insulated -from the building. The examples show the necessity of leaving the -design and erection of lightning conductors to those persons who have -made a thorough study of the subject, since the work is by no means so -free from complexity as is commonly supposed. - -[Illustration: Fig. 40. ST. GEORGE’S CHURCH, LEICESTER.] - -Figs. 40 and 41 show the tower and spire of St. George’s Church, -Leicester, after being severely damaged by lightning on August 1st, -1846. The storm, during the course of which it was struck, was very -violent, of prolonged duration, and accompanied by torrents of rain and -hail. Mr. Charles Tomlinson, F.R.S., in his work on ‘The Thunderstorm,’ -thus describes the catastrophe:— - -‘It was at five minutes past eight, after one or two peals of unusual -distinctness, that the church of St. George was struck with a report -resembling the discharge of cannon, and with a concussion of the air -which shook the neighbouring houses, and extinguished a lamp burning at -the entrance of the News-room, many hundred feet distant. The Sexton -had gone into the church, as usual, to toll the eight o’clock bell; -but was so terrified by the “fire-balls” that he saw in the sky, and -by the fact that once or twice the clapper struck the side of the bell -without his agency, that he made his work as short as possible, and -had just gone out and locked the churchyard gate when the stroke fell. -Two of the spectators of this awful event were Captain Jackson and the -Rev. R. Burnaby, the rector of the parish, who both described the flash -as a vivid stream of light, followed by a red and globular mass of -fire, and darting obliquely from the north-west, with immense velocity, -against the upper part of the spire. For the distance of forty feet -on the eastern side, and nearly seventy on the west, the massive -stone-work of the spire was instantly rent asunder and laid in ruins. -Large blocks of stone were hurled in all directions, broken into small -fragments, and in some cases, as there is every reason to believe, -reduced to powder. One fragment of considerable size was hurled against -the window of a house three hundred feet distant, shattering to pieces -the woodwork, as well as fourteen out of the sixteen panes of glass, -and strewing the room within with fine dust and fragments of glass. It -has been computed that a hundred tons of stone were on this occasion -blown to a distance of thirty feet in three seconds. In addition to -the shivering of the spire, the pinnacles at the angles of the tower -were all more or less damaged, the flying buttresses cracked through -and violently shaken, many of the open battlements at the base of the -spire knocked away, the roof of the church completely riddled, the -roofs of the side-entrances destroyed, and the stone staircases of the -gallery shattered. The top of the spire, when left without support -beneath, fell perpendicularly downwards, inside the steeple, causing -much devastation in its descent. Falling through the uppermost storey, -and carrying along with it the bell and its solid supports, the ruined -spire entered the room containing the clock, dashed the works to -pieces, and penetrating the strong and well-supported floor, descended -with additional momentum through the third and fourth floors (the -latter being that just deserted by the prudent sexton), and reached the -paved vestibule with so furious a shock as to drive in a portion of -the strong foundation-arch, by which the weight of the whole tower was -supported. On looking upward from the scene of ruin in this vestibule, -the tower appeared like a well, so small were the vestiges of its -various storeys.’ - -[Illustration: Fig. 41. ST. GEORGE’S CHURCH, LEICESTER.] - -After minute examination, it was evident that the course of the -lightning had been nearly as follows:—‘The flash first struck the -gilded vane, marks of lightning being perceptible between its bevelled -edges. After traversing the vane and spindle, and the terminating iron -supports, the only path left for the fluid was through a series of -iron cramps, separated by masses of sandstone; and here it was that -the explosion commenced--the stone being torn and hurled aside as it -came in the path of the lightning to the lowest lead lights of the -spire. Most of these iron cramps were found to be powerfully magnetic; -and one of them, eight weeks afterwards, sustained a very considerable -brush of steel filings at its edges. The lattices of the lights on -three sides of the spire were little injured; but on the fourth side -the stone-work was shattered, and the lattice singularly twisted and -partially fused. Here, it appears, another violent explosion took -place, and the lightning diverging struck the north-west pinnacle, -attracted apparently by the copper bolt by which the stones were held -together. It also struck the large cast-iron pipe on the other side -of the spire, reaching from the tower-battlements to the roof of the -church; and during its passage down the pipe, and at an inequality in -the surface of the metal, it displayed the most extraordinary expansive -force, bursting open and scattering to a distance portions of metal of -great solidity and weight. From the leadwork of the roof the lightning -was conducted to the leaden gutters, and so finally to the earth. - -‘The course of the remaining current in the interior of the tower -was first to be traced on the lattices of the belfry, then in the -clock-room, where the works of the clock were strongly magnetised, -thence in at least three different directions to the outside of the -tower. The external faces of the clock were not much altered, the hands -were, however, slightly discoloured, and the blackened surfaces of -the dials covered with streaks, as if smeared with a painter’s brush. -On quitting the dial faces on the northern and southern sides of the -tower, the lightning evidently fell upon the leads of the side lobbies, -and was finally carried off by the two iron pipes connecting their -roofs with the earth. Both these pipes were chipped and injured, and -one of them was perforated, as if by a musket-shot, a few inches from -the ground. The edges of this fracture were found to possess magnetic -power. Thus, besides the division of the current at the upper part of -the spire, there was a second division in at least three directions -from the clock-room and dial faces. The roof of the church throughout -its whole extent showed signs of an extraordinary diffusion of the -electric current; and in almost every place where one piece of metal -overlapped another, a powerful explosion had evidently taken place.’ - -As far as is known the church was unprovided with any lightning -conductor. The same storm produced most disastrous effects in other -parts of the Kingdom. Seven thousand panes of glass were broken by the -hail in the Houses of Parliament; three hundred at the Police Office, -Scotland Yard; other buildings in the metropolis suffered to a similar -extent, the glass in the picture gallery at Buckingham Palace being -totally destroyed and the apartment flooded with water. - -[Illustration: Fig. 42. WEST-END CHURCH, SOUTHAMPTON.] - -Fig. 42 shows the spire of the church at West End, Southampton, which -was struck by lightning on June 10, 1875. A large quantity of the -stone-work was broken by the passage of the electric discharge, and -some of the pieces were thrown to a great distance. - -[Illustration: Fig. 43. MERTON COLLEGE CHAPEL, OXFORD.] - -On September 27, 1875, the tower of the chapel of Merton College, -Oxford, was struck by lightning. The damage done was confined to the -mutilation of one of the corner pinnacles and the displacement of -fragments of some of the stone-work which were thrown on to the leads -and the pathway beneath. Some workmen were on the leads at the time, -but fortunately were not hurt. The tower had lately been restored, -and the scaffolding had only been removed a few days previous to the -accident. A gentleman who had taken shelter from the storm in one of -the workmen’s sheds beneath the tower was startled by seeing fragments -of stone falling from above; looking up, he discovered that the tower -had been struck, and immediately informed the college authorities. -On ascending the tower it was found that one of the eight crocketted -pinnacles had been struck. This pinnacle occupied the south-western -corner, and had been completely and cleanly severed from summit to -base. Fortunately, the stone-work displaced--which weighed about three -hundredweight--was thrown on to the roof of the tower, a distance of -twenty-five feet. The vane, slightly fused by the electric discharge, -was found embedded in an upright position in the leads. The mouldings -on the edges of the pinnacle were divided to the extent of four feet, -and many of the stones were turned entirely round. - -[Illustration: Fig. 44.] - -The tower, which was erected in 1424, and is one of the landmarks of -Oxford, had not up to the time of the accident been provided with -lightning conductors, but they have since been affixed to the building. - -Fig. 44 shows the steeple of St. Bride’s Church, Fleet Street, London, -which was severely damaged by lightning on June 18, 1764. The spire of -this steeple is built in four storeys, surmounted by an obelisk. These -four storeys are braced together by means of horizontal iron bars; -another iron bar, about twenty feet long and two inches square, passes -through the upper part of the obelisk and supports the weathercock -and other ornamental work on the top; there is also a great deal of -iron-work used generally in the construction of this part of the -building, thus forming a complete series of discontinuous metallic -masses. When the lightning struck the building it was received by the -long iron bar which supported the vane; at the lower end of the bar -the electric discharge, meeting with no metallic conductor, burst with -great violence, shattering the stone on which the bar rested; the -lightning then pursued its course to earth, leaping from one piece -of metal to another and breaking the stone-work in its way. The last -trace of it was found at the west window of the belfry, from whence it -seems to have found a road to the earth. The damage sustained by the -structure was so great that eighty-five feet of the spire had to be -entirely rebuilt. - -The edifice was afterwards attentively examined (as explained in a -previous chapter) by Dr. Watson, a well-known electrician in those -days, who reported to the Royal Society that the accident ‘completely -indicated the great danger of insulated masses of metal to buildings -from lightning; and, on the contrary, evinced the utility and -importance of masses of metal continued and properly conducted, in -defending them from its direful effects. The iron and lead employed -in this steeple, in order to strengthen and preserve it, did almost -occasion its destruction; though, after it was struck by the lightning, -had it not been for these materials keeping the remaining parts -together, a great part of the steeple must have fallen. - -[Illustration: Fig. 45.] - -Fig. 45 shows the condition of St. Michael’s Church, at Black Rock, -near Cork, after being struck by lightning on January 29, 1836. The -damage done was entirely on the windward side of the steeple, caused, -as is suggested in Mr. Tomlinson’s work, by this side receiving the -greatest quantity of rain, and so being rendered the ‘line of least -resistance,’ but not a sufficiently good conductor to carry off the -discharge to earth. - -On Trinity Sunday, June 8th, 1879, a violent thunder-storm broke -over the town of Wrexham about half-past three in the afternoon, -during which the spire of St. Mark’s Church was struck by lightning. -A Sunday-school class was being held in the room at the base of the -spire, and the teacher and five of his scholars were burnt, three of -them severely, and one had his leg broken. Some of the stone-work of -the spire was also displaced and thrown down. The spire was fitted with -a copper conductor, but it was of too small a calibre, and it is very -doubtful whether the earth connection was all it should have been. - -Many other cases might be enlarged upon, but enough have been given -to prove the imperative need for a more general use of lightning -conductors on all public and private buildings. Another equally -important necessity is that lightning conductors should be erected on -sound principles, and also be periodically examined and tested by some -competent person. - - -_PUBLIC BUILDINGS STRUCK BY LIGHTNING._ - - +---------+---------------------+------------------+-----------------+ - | DATE | BUILDING | DAMAGE | AUTHORITY | - +---------+---------------------+------------------+-----------------+ - | 1589. | Nicholas Tower, | The tower burnt | From original | - | July 16| Hamburg | down | notices in | - | | | | Reimarus, Bl. | - | | | | 315 | - | | | | | - | 1670. | Nicholas Church, | Damaged | Phil. Trans. | - | June 29| Straland | | v. 2084 | - | | | | | - | 1673. | Pharr Church, | Damaged | Breslauer | - | June 29| Epperies, Hungary | | Samml. 1717, | - | | | | p. 64 | - | | | | | - | 1693 | Oundle Church | Set on fire | Phil. Trans. | - | | | | xvii. 710 | - | | | | | - | 1700. | Principal church, | Set on fire and | Mém. de | - | Oct. 9 | Troies | shattered | l’Acad. de Sc. | - | | | | Paris, 1760, | - | | | | p. 65 | - | | | | | - | 1708. | All Hallows’ | Damaged | Phil. Trans. | - | July | Church, Colchester | | 432 | - | | | | | - | 1711. | Principal town | Damaged | Scheuchzer, | - | May 20 | tower in Bern; | | Meteorol. | - | | houses adjoining | | Helv. p. 35 | - | | | | | - | 1711. | The belfry of the | Set on fire | Scheuchzer, | - | May 23 | church at Solingen | | Meteorol. | - | | | | Helv. p. 28 | - | | | | | - | 1714. | Elizabeth Tower, | Damaged | Breslauer | - | June 21| Breslau | | Samml. 1717, | - | | | | p. 68 | - | | | | | - | 1717. | Church at | Seven persons | Breslauer | - | July 2 | Seidenberg, near | killed | Samml. 1718, | - | | Zittau | | p. 1534 | - | | | | | - | 1718. | Twenty-four | Set on fire and | Hist. de | - | April | churches between | shattered | l’Acad. de Sc. | - | 14, 15 | Landerneau and | | Paris, 1719, | - | | St. P. de Léon, | | p. 21 | - | | Brittany | | | - | | | | | - | 1718. | Church tower at | Set on fire | Breslauer | - | Dec. 14| Eutin | | Samml. 1718, | - | | | | p. 1968 | - | | | | | - | 1725. | Church tower, | Lightning | Breslauer | - | Dec. 18| Winterthur | followed an | Samml. 1725, | - | | | accidental | p. 166 | - | | | conductor, and | | - | | | resulted in | | - | | | melting it | | - | | | | | - | 1728. | Church tower, | Shattered | Reimarus, Bl. | - | Aug. 25| Mellingen, in Baden| | 145 | - | | | | | - | 1731. | Three villages | Destroyed | Gent.’s Mag. | - | July | near Geneva | | p. 309 | - | | | | | - | 1732. | The Escurial at | Set on fire | Gent.’s Mag. | - | Oct. | Madrid | | p. 1034 | - | | | | | - | 1743. | Liberton Church, | Steeple | Gent.’s Mag. | - | Aug. | Scotland | destroyed | xiv. 450 | - | | | | | - | 1745. | Tower of | Shattered. | Reimarus, Bl. | - | July 21| monastery, Bologna | Lightning | 93 | - | | | followed an | | - | | | accidental | | - | | | conductor, and | | - | | | melted it | | - | | | | | - | 1746. | Tower of the | The ball on the | Reimarus, 198 | - | May 21 | School Church, | tower bent, | | - | | Halle | and other | | - | | | mechanical | | - | | | effects | | - | | | | | - | 1747. | Tower of the | Physio. and | Mém. de | - | Aug. 20| College Church, | mechanical | l’Acad. de Sc. | - | | Pluviers | effects | Paris, 1748, | - | | | | p. 572 | - | | | | | - | 1748. | Top of a church | Shattered and | Hamburg | - | May 31 | tower, Witzendorf | tore off the | Magazine, ix. | - | | | roof; melted | 301 | - | | | and shattered | | - | | | accidental | | - | | | conductor | | - | | | | | - | 1750. | Church tower, | Set on fire | Phil. Trans. | - | Feb. 5 | Danbury, Essex | | xlvi. 611 | - | | | | | - | 1750. | Tower of Dutch | Lightning | Franklin, | - | Spring | Church, New York | followed an | Experiments | - | | | accidental | and | - | | | conductor, | Observations | - | | | which was | xv. 180 | - | | | shattered, and | | - | | | caused other | | - | | | mechanical | | - | | | effects | | - | | | | | - | 1751. | Tower of church, | Lightning | Phil. Trans. | - | June 6 | South Moulton, | followed an | xlvii. 330 | - | | Devonshire | accidental | | - | | | conductor, | | - | | | which was | | - | | | shattered, and | | - | | | caused other | | - | | | mechanical | | - | | | effects | | - | | | | | - | 1752. | Church tower, | Tower damaged; | Schwed. Abh. | - | June 19| Alfwa, Sweden | several persons | xv. 80 | - | | | injured | | - | | | | | - | 1753. | Darlington Church | Much damaged | Gent.’s Mag. | - | Mar. | | | xxiii. 145 | - | | | | | - | 1753. | Church of Les | Reduced to ashes | Gent.’s Mag. | - | Oct. | Filles de St. | | xxiii. 487 | - | | Sacrament, Naples | | | - | | | | | - | 1754. | Belfry of Newbury | Point of spire | Phil. Trans. | - | June 16| Church | shattered, | xlix. 307 | - | | | accidental | | - | | | conductor | | - | | | melted, and | | - | | | other damage | | - | | | | | - | 1755 | Danish Church, | Clock damaged | Phil. Trans. | - | | Wellclose Square | | xlix. 298 | - | | | | | - | 1755. | St. Aubin Church, | Much damaged | Gent.’s Mag. | - | Dec. | Lorraine | | xxv. 42 | - | | | | | - | 1757. | Lostwithiel | Much damaged | Gent.’s Mag. | - | Jan. | Church, Cornwall | | xxviii. 427 | - | | | | | - | 1757. | Christ Church, | Much damaged | Gent.’s Mag. | - | Nov. | Dublin | | xxvii. 527 | - | | | | | - | 1759. | Great Billing | Steeple | Ann. Reg. ii. | - | April | Church, | destroyed | 84 | - | | Northamptonshire | | | - | | | | | - | 1759. | Portsmouth Church, | Much damaged | Gent.’s Mag. | - | May | New Hampshire | | xxix. 355 | - | | | | | - | 1759. | Jacob Church, | Several persons | Reimarus, Bl. | - | June 10| Aumale | injured | 158 | - | | | | | - | 1760. | Church, Altona | Lightning | Reimarus, 59 | - | July 16| | struck the | | - | | | copper covering | | - | | | on the top of | | - | | | spire, followed | | - | | | accidental | | - | | | conductors, and | | - | | | melted them | | - | | | | | - | 1761. | Shifnal Church, | Greatly damaged | Ann. Reg. iv. | - | June | Norfolk | | 136 | - | | | | | - | 1761. | Ludgvan Church, | Greatly damaged | Ann. Reg. iv. | - | July | near Penzance | | 142 | - | | | | | - | 1763. | Harrow Church | Set on fire | Gent.’s Mag. | - | Mar. | | | xxiii. 142 | - | | | | | - | 1763. | Salisbury Cathedral | Damaged | Gent.’s Mag. | - | Mar. | | | xxiii. 143 | - | | | | | - | 1763. | Southam Church, | Damaged | Gent.’s Mag. | - | Mar. | Warwickshire | | xxxiii. 142 | - | | | | | - | 1764. | St. Bride’s | Spire struck | Phil. Trans. | - | June 18| Church, London | and much damaged| liv. 227 | - | | | | | - | 1765. | Bicester Church | Much damaged | Gent.’s Mag. | - | Aug. | | | xxxv. 391 | - | | | | | - | 1766. | Skipton-in-Craven | Much damaged | Ann. Reg. ix. | - | July | Church | | 118 | - | | | | | - | 1766. | St. Mary’s Church, | Much damaged | Ann. Reg. ix. | - | Aug. | Bury St. Edmunds | | 122 | - | | | | | - | 1767. | Provence, France | Three churches | Ann. Reg. x. 81 | - | April | | set on fire | | - | | | | | - | 1767. | Mentz Cathedral | Set on fire | Ann. Reg. x. 92 | - | May | | | | - | | | | | - | 1767. | Nicholas Tower, | Lightning | Reimarus, Bl. | - | Aug. 6 | Hamburg | followed | 291 | - | | | accidental | | - | | | conductors, and | | - | | | partly melted | | - | | | them | | - | | | | | - | 1767. | Genoa | Several | Ann. Reg. x. | - | Sept. | | churches damaged| 126 | - | | | | | - | 1768. | Church tower in | Damaged. | Haarlem Verh. | - | Aug. 21| Alem | Several persons | xiv. 34 | - | | | injured | | - | | | | | - | 1770. | St. Keverns | Damaged. | Hemmer, Act. | - | Feb. 18| Church, Cornwall | Several persons | Acd. Palat. | - | | | injured | iv. 37 | - | | | | | - | 1771. | Nicholas Church, | Lightning | Ackermann’s | - | Feb. 2 | Kiel | followed | notice, Kiel, | - | | | accidental | 1772 | - | | | conductor, and | | - | | | left traces | | - | | | | | - | 1772. | St. Paul’s | Lightning | Arago, iv. 88 | - | Mar. | Cathedral, London | followed | | - | | | accidental | | - | | | conductor, and | | - | | | left traces | | - | | | | | - | 1773. | Lighthouse at | Destroyed | Gent.’s Mag. | - | April | Villafranca, Nice | | xliii. 246 | - | | | | | - | 1773. | Rhichenback, Saxony | Town reduced to | Ann. Reg. xvi. | - | June | | ashes | 115 | - | | | | | - | 1773 | St. Peter’s | Shattered the | Phil. Trans. | - | | Church, London | tower roof | lxv. 336 | - | | | | | - | 1774. | Buckland Church, | Damaged | Ann. Reg. | - | Aug. | near Dover | | xvii. 140 | - | | | | | - | 1775. | St. Colomb Church, | Much damaged | Ann. Reg. | - | Feb. | Cornwall | | xviii. 91 | - | | | | | - | 1775. | A church in Munich | Tower injured | Epp. 90 | - | June 27| | | | - | | | | | - | 1776. | Cuckfield Church, | Much damaged | Ann. Reg. xix. | - | Aug. | Suffolk | | 170 | - | | | | | - | 1778. | Church in Altona | Metal melted | Reimarus, Bl. | - | April | | | 64 | - | 15 | | | | - | | | | | - | 1780. | Church of the Holy | Injured | Reimarus, N.B. | - | Sept. | Spirit, Hamburg | | 47 | - | | | | | - | 1780. | Hammersmith Church | Much damaged | Ann. Reg. | - | Oct. | | | xxiii. 230 | - | | | | | - | 1783. | Ashbourne Church, | Steeple | Gent.’s Mag. | - | July | Derbyshire | demolished | liii. 707 | - | | | | | - | 1783 | St. Mary’s, | Steeple | | - | | Leicester | demolished | | - | | | | | - | 1786. | Church in | Shattered. | Act. Acad. | - | June 26| Wachenheim | People injured | Theod. Palat. | - | | | | vi. 332 | - | | | | | - | 1787. | St. Mary’s Church, | Much damaged | Gent.’s Mag. | - | June | Grenoble | | lvii. 820 | - | | | | | - | 1787. | Vendamir Church, | Several persons | Gent.’s Mag. | - | June | Vercovia | killed | lvii. 820 | - | | | | | - | 1787. | St. Gregorius | Set on fire | Gent.’s Mag. | - | June | Church, Prague | | lvii. 820 | - | | | | | - | 1787. | Cranbrook Church | Much damaged | Gent.’s Mag. | - | June | | | lvii. 824 | - | | | | | - | 1789. | Pforzheim Church | Entirely | Gent.’s Mag. | - | May | | consumed, | lix. 754 | - | | | with thirty | | - | | | adjoining | | - | | | buildings | | - | | | | | - | 1789. | Barnewell Church, | Damaged | Gent.’s Mag. | - | June | near Oundle | | lix. 665 | - | | | | | - | 1790. | Beckenham Church | Set on fire | Ann. Reg. | - | Dec. | | | xxxii. 229 | - | | | | | - | 1790. | Horsham Church | Set on fire | Ann. Reg. | - | Dec. | | | xxxii. 229 | - | | | | | - | 1791. | Ashton-under-Lyne | Much damaged | Ann. Reg. | - | Jan. | Church | | xxxiii. 3 | - | | | | | - | 1791. | Rainham Church | Much damaged | Gent.’s Mag. | - | Oct. | | | lxi. 1050 | - | | | | | - | 1795. | Castor Church | Much damaged | Gent.’s Mag. | - | June | | | lxv. 517 | - | | | | | - | 1795. | Church in Bergen, | Set on fire | Gilb. Ann. | - | Dec. 25| Norway | | xxix. 176 | - | | | | | - | 1797. | Grantham Church | Damaged | Gent.’s Mag. | - | July | | | lxviii. 104 | - | | | | | - | 1797. | Caldecot Church, | Spire much | Gent.’s Mag. | - | Aug. | Rutland | damaged | lxvii. 817 | - | | | | | - | 1801. | Corby Church | Damaged | Gent.’s Mag. | - | July | | | lxxi. 659 | - | | | | | - | 1804. | St. Gertrude | Burnt by | Gent.’s Mag. | - | Mar. | Church at Nevelles | lightning | lxxiv. 368 | - | | | | | - | 1804. | St. Maria at | Burnt by | | - | Mar. | Oudenard in | lightning | | - | | Flanders | | | - | | | | | - | 1804. | Edenham Church, | Damaged | Ann. Reg. | - | June | Lincoln | | xlvi. 394 | - | | | | | - | 1804. | Hanslope Church, | Spire destroyed | Ann. Reg. | - | June | Bucks | | xlvi. 395 | - | | | | | - | 1806. | Sunbury Church, | Damaged | Ann. Reg. | - | July | Middlesex | | xlviii. 426 | - | | | | | - | 1807 | Montvilliers | Damaged | Howard’s | - | | Church, France | | Climate of | - | | | | London, ii. 29 | - | | | | | - | 1810. | Attercliffe Chapel | Much damaged | Gent.’s Mag. | - | July | | | | - | | | | | - | 1811. | Ashford Church | Much damaged | Gent.’s Mag. | - | June | | | lxxxi. 584 | - | | | | | - | 1811. | Ledbury Parish | Damaged | Gent.’s Mag. | - | Dec. | Church | | lxxxi. 650 | - | | | | | - | 1812 | St. Pelverin | Set on fire and | Howard’s | - | | Church, Department | burnt to the | Climate of | - | | of the Loire | ground | London, ii. 165| - | | | | | - | 1813 | Bridgwater Church | Spire destroyed | Howard’s | - | | | | Climate of | - | | | | London, ii. 222| - | | | | | - | 1813 | Weston Zoyland | Tower much | Howard’s | - | | Church | damaged | Climate of | - | | | | London, ii. 222| - | | | | | - | 1814. | Thackstead Church, | Much damaged | Gent.’s Mag. | - | Nov. | Essex | | lxxxiv. 491 | - | | | | | - | 1815 | The steeples of | Struck and set | Howard’s | - | | many churches in | on fire nearly | Climate of | - | | Belgium, in places | at the same hour| London, ii. 259| - | | far distant from | | | - | | one another | | | - | | | | | - | 1816. | Worschetz, county | Church and the | Ann. Reg. | - | July | of Temeswar | town greatly | lviii. 102 | - | | | damaged | | - | | | | | - | 1816. | Moselle Church | Damaged | Ann. Reg. | - | Oct. | | | lviii. 161 | - | | | | | - | 1817. | St. Paulinas | Set on fire | Ann. Reg. lix. | - | Mar. | Church, Germany | | 15 | - | | | | | - | 1819. | St. Martin’s | Much damaged | Ann. Reg. lxi. | - | Jan. | Church, Guernsey | | 5 | - | | | | | - | 1819. | Sedgeford Church, | Much damaged | Ann. Reg. lxi. | - | July | Lynn | | 50 | - | | | | | - | 1821. | Tower of | Church burned | Gilb. Ann. | - | May 7 | Katherine’s | | lxviii. 224 | - | | Church, | | | - | | Gross-Selten | | | - | | | | | - | 1821. | Wooden Tower of | Tower burned | Gilb. Ann. | - | May 7 | Katherine Church, | | lxviii. 224 | - | | Tischendorf | | | - | | | | | - | 1821. | Church at Carlsruhe | Damaged | Gilb. Ann. | - | May 8 | | | lxviii. 224 | - | | | | | - | 1821. | Redcliffe Church, | Much damaged | Gent.’s Mag. | - | April | Bristol | | xci. 367 | - | | | | | - | 1822. | Church at | Damaged | Wurtemberger | - | Jan. 15| Gerstetten | | Jahreshafte, | - | | | | xi. 463 | - | | | | | - | 1822. | North Luffenham | Much damaged | Gent.’s Mag. | - | June | Church, Rutland | | xcii. 636 | - | | | | | - | 1822. | Church at Chatham | Spire ripped | Tomlinson’s | - | Aug. | | open | Thunderstorm, | - | | | | p. 165 | - | | | | | - | 1822. | Rouen Cathedral | Set on fire | Tomlinson’s | - | Sept. | | | Thunderstorm, | - | | | | p. 165 | - | | | | | - | 1822. | St. Peter’s | Reduced to ruins | Gent.’s Mag. | - | Oct. | Church, Venice | | xcii. 553 | - | | | | | - | 1823 | Kemble Church, | Spire destroyed | Howard’s | - | | Wilts | | Climate of | - | | | | London, iii. | - | | | | 135 | - | | | | | - | 1823. | Shaugh Church, | Tower struck | Tomlinson’s | - | Feb. | near Plymouth | and much | Thunderstorm, | - | | | shattered. An | p. 165 | - | | | iron conductor | | - | | | had been | | - | | | erected about | | - | | | two years | | - | | | before, but | | - | | | this had rusted | | - | | | and gone to | | - | | | decay | | - | | | | | - | 1824. | Church at | Damaged | Würtemberger | - | July 10| Simmerfeld | | Jahreshafte, | - | | | | xi. 463 | - | | | | | - | 1824. | Charles Church, | Steeple struck, | Tomlinson’s | - | Nov. | Plymouth | and the small | Thunderstorm, | - | | | brass rod | p. 165 | - | | | erected as | | - | | | a lightning | | - | | | conductor | | - | | | knocked to | | - | | | pieces | | - | | | | | - | 1825— | Torrington Church, | Tower and | Tomlinson’s | - | about | North Devon | steeple ruined. | Thunderstorm, | - | | | They had to be | p. 165 | - | | | rebuilt | | - | | | | | - | 1826. | Alphington Church, | Much damaged | Ann. Reg. | - | June | near Exeter | | 1826, p. 97 | - | | | | | - | 1827 | Pailant Church, | Considerably | Howard’s | - | | Chichester | damaged | Climate of | - | | | | London, iii. | - | | | | 259 | - | | | | | - | 1827. | Church Tower, | Set on fire, | Würtemberger | - | Jan. 11| Bussen | although | Jahreshafte, | - | | | covered with | xi. 463 | - | | | snow | | - | | | | | - | 1828. | Edlesborough Church | Set on fire | Gent.’s Mag. | - | April | | | xcviii. 358 | - | | | | | - | 1828. | Kingsbridge | Steeple rent, | Tomlinson’s | - | June | Church, Devon | and other damage| Thunderstorm, | - | | | | p. 165 | - | | | | | - | 1828. | Kilcoleman Church, | Spire destroyed | Ann. Reg. p. | - | Oct. | co. Mayo | | 131 | - | | | | | - | 1830. | Independent | Damaged | Ann. Reg. p. | - | July | Chapel, Edgworth | | 101 | - | | Moor, near Bolton | | | - | | | | | - | 1830. | Marlborough | Tower and | Tomlinson’s | - | Aug. | Church, near | church severely | Thunderstorm, | - | | Kingsbridge, Devon | damaged | p. 166 | - | | | | | - | 1831. | Kilmichael Church, | Much damaged | Ann. Reg. p. 39 | - | Feb. | Glassire | | | - | | | | | - | 1833. | Strasburg Cathedral | Much damaged | Builder, ii. 39 | - | Aug. | | | | - | | | | | - | 1835. | Church Tower, | Much shattered | Würtemb. | - | May 16 | Endersbach | | Jahreshafte, | - | | | | xi. 465 | - | | | | | - | 1835. | Durham Cathedral | Western tower | Ann. Reg. p. 94 | - | June | | damaged | | - | | | | | - | 1836. | Black Rock, near | Spire demolished | Tomlinson’s | - | Jan. | Cork | | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1836. | Christ Church, | The spire | Tomlinson’s | - | Nov. | Doncaster | shattered and | Thunderstorm, | - | | | the church | p. 166 | - | | | greatly | | - | | | injured. The | | - | | | roof was | | - | | | smashed in, and | | - | | | the churchyard | | - | | | presented | | - | | | a scene of | | - | | | ruin and | | - | | | devastation. | | - | | | The spire was | | - | | | surmounted by a | | - | | | ball of glass | | - | | | to keep off the | | - | | | lightning! | | - | | | | | - | 1837. | Hoo Church, Kent | Set on fire | Gent.’s Mag. | - | June | | | N.S. viii. p. | - | | | | 80 | - | | | | | - | 1839. | Church tower in | Damaged | Arago, Notiz, | - | Jan 8 | Hasselt | | 125 | - | | | | | - | 1841. | Spitalfields, | Spire rent, and | Tomlinson’s | - | Jan. | London | other damages | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1841 | Streatham | Spire nearly | Tomlinson’s | - | | | destroyed, and | Thunderstorm, | - | | | church set on | p. 166 | - | | | fire | | - | | | | | - | 1841. | Walton Church, | Spire destroyed | Tomlinson’s | - | May 10 | Stafford | | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1841. | St. Michael’s, | Beautiful spire | Tomlinson’s | - | Aug. 24| Liverpool | shattered, and | Thunderstorm, | - | | | clock injured | p. 166 | - | | | | | - | 1841. | St. Martin’s, | Spire | Tomlinson’s | - | Aug. 24| Liverpool | shattered, and | Thunderstorm, | - | | | other damage | p. 166 | - | | | | | - | 1841 | Wolverhampton | Set on fire | Annals of | - | | Parish Church | | Electricity, | - | | | | vi. 504 | - | | | | | - | 1841 | Spitalfields Church | Steeple damaged | Annals of | - | | | | Electricity, | - | | | | vi. 504 | - | | | | | - | 1842. | Brixton Church, | Dome and | Tomlinson’s | - | April | London | building much | Thunderstorm, | - | 24 | | rent | p. 166 | - | | | | | - | 1842. | St. Martin’s, | Spire | Tomlinson’s | - | July 28| London | shattered; cost | Thunderstorm, | - | | | of repair, | p. 166 | - | | | 1,500_l._ | | - | | | | | - | 1843. | Exton Church, | Spire | Tomlinson’s | - | April | Rutland | destroyed; | Thunderstorm, | - | 25 | | church set on | p. 166 | - | | | fire and nearly | | - | | | destroyed | | - | | | | | - | 1843. | St. Mark’s, Hull | Slightly damaged | Tomlinson’s | - | May 25 | | | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1843. | North Huish, near | Steeple | Tomlinson’s | - | Oct. | Modbury, Devon | shattered | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1844. | Oving Church, near | Spire damaged | Tomlinson’s | - | Mar. | Chichester | | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1844 | St. Clement’s, | Clock injured | Tomlinson’s | - | | London | | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1844. | Magdalen Tower, | One of the | Tomlinson’s | - | July | Oxford | pinnacles | Thunderstorm, | - | | | damaged; | p. 166 | - | | | staircase | | - | | | injured | | - | | | | | - | 1844. | Stannington | Seriously | Tomlinson’s | - | July 20| Church, near | damaged | Thunderstorm, | - | | Sheffield | | p. 166 | - | | | | | - | 1846. | Church near | Damaged | Compt. Rend. | - | June 14| Chambrey | | xxiii. 153 | - | | | | | - | 1846. | St. George’s | Spire destroyed | Builder, iv. | - | Aug. | Church, Leicester | | 395 | - | | | | | - | 1846. | Dedham Church, | Much damaged | Builder, iv. | - | Aug. | Essex | | 395 | - | | | | | - | 1846. | Village of | Completely | Journal des | - | Oct. | Schledorf, near | destroyed | Debats, Oct. | - | | Munich | | 20, 1846 | - | | | | | - | 1847. | Her Majesty’s | One tower much | Builder, vii. | - | June | palace, Osborne | damaged | 291 | - | | | | | - | 1847. | Church in Thann | Much damaged | Compt. Rend. | - | June | | | xxix. 485 | - | | | | | - | 1847. | Walton Church, | Lightning | Tomlinson’s | - | Aug. | Lincolnshire | entered at the | Thunderstorm, | - | | | belfry; one man | p. 158 | - | | | killed, several | | - | | | injured | | - | | | | | - | 1849. | St. Saviour’s, | Damaged | Ann. Reg. xci. | - | July | Southwark | | 80 | - | | | | | - | 1850. | Norton-by-Gaulby | Spire much | Builder, viii. | - | May | Church | damaged | 248 | - | | | | | - | 1850. | Little Stretton | Much damaged | Builder, viii. | - | May | Church | | | - | | | | | - | 1850. | Roman Catholic | Bell-turret | Builder, viii. | - | Aug. | Church, York | shattered | 405 | - | | | | | - | 1850. | Keysoe Church | Considerably | Builder, viii. | - | Oct. | | damaged | 509 | - | | | | | - | 1850. | Cobridge Church, | Considerably | Builder, viii. | - | Nov. | Potteries | damaged | 533 | - | | | | | - | 1851. | St. Sepulchre’s | Much damaged | Builder, ix. | - | May | Church, Northampton| | 329 | - | | | | | - | 1851. | Edinburgh Assembly | Much damaged | Builder, ix. | - | May | Hall | | 305 | - | | | | | - | 1851. | Boulogne Cathedral | Dome damaged | Builder, ix. | - | June | | | 415 | - | | | | | - | 1852. | Ross Church, | Severely damaged | Tomlinson’s | - | July 6 | Hereford | | Thunderstorm, | - | | | | p. 166 | - | | | | | - | 1852. | Woolpit Church, | Tower and spire | Builder, x. 492 | - | July | Suffolk | destroyed | | - | | | | | - | 1852. | Leighton Buzzard | Much damaged | Builder, x. 492 | - | July | Church | | | - | | | | | - | 1852 | Exton Parish Church | Church nearly | Builder, xii. | - | | | destroyed | 575 | - | | | | | - | 1853. | Derby Church | Much damaged | Builder, xi. 28 | - | Jan. | | | | - | | | | | - | 1853. | Parish Church, | Entirely | Builder, xi. 43 | - | Jan. | Eskdalemuir, | destroyed | | - | | Dumfries | | | - | | | | | - | 1853. | Lincoln Cathedral | Struck | Tomlinson’s | - | Feb. | | north-west | Thunderstorm, | - | | | pinnacle of | p. 166 | - | | | the broad | | - | | | tower; set on | | - | | | fire; narrowly | | - | | | escaped | | - | | | destruction | | - | | | | | - | 1853. | Skipton Church | Much damaged | Builder, xi. | - | July | | | 423 | - | | | | | - | 1853. | Hereford Old | Slightly damaged | Builder, xi. | - | July | Parish Church | | 487 | - | | | | | - | 1853. | Chaddesley Corbett | Considerably | Builder, xi. | - | Nov. | Church | damaged | 704 | - | | | | | - | 1854. | Hanwell Church | Spire much | Builder, xii. | - | May | | damaged | 283 | - | | | | | - | 1854. | Helpringham Church | Spire much | Builder, xii. | - | May | | damaged | 269 | - | | | | | - | 1854. | Ealing Church | Had a common | Tomlinson’s | - | June | | conductor, | Thunderstorm, | - | | | which was | p. 167 | - | | | fused; the | | - | | | church slightly | | - | | | damaged | | - | | | | | - | 1854. | Ashbury Church | Had a common | Tomlinson’s | - | July | | conductor, | Thunderstorm, | - | | | which was | p. 167 | - | | | fused; church | | - | | | damaged, but | | - | | | not considerably| | - | | | | | - | 1854. | Tower of Magdalen | Much damaged | Tomlinson’s | - | July 19| College, Oxford | | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1854. | National School | Three children | Ann. Reg. | - | Aug. | Chapel, St. Mary, | killed, several | xcvi. 140 | - | | Ipswich | injured | | - | | | | | - | 1855. | Trinity Church, | Slightly damaged | Builder, xiii. | - | May | Southwark | | 239 | - | | | | | - | 1855. | St. Mark’s, | Considerably | Builder, xiii. | - | May | Myddelton Square | damaged | 239 | - | | | | | - | 1855. | Holy Trinity | Slightly damaged | Builder, xiii. | - | July | Church, Brompton | | 348 | - | | | | | - | 1855. | St. Ebbe’s Parish | Slightly damaged | Builder, xiii. | - | July | Church | | 348 | - | | | | | - | 1856. | Chimney at | Much damaged; | Tomlinson’s | - | Feb. | Liverpool, 310 ft. | struck at 20 | Thunderstorm, | - | | high | yds. below the | p. 167 | - | | | top | | - | | | | | - | 1856. | Hemingbrough Ch. | Much damaged | Builder, xiv. | - | June | | | 348 | - | | | | | - | 1856. | Clapton Church | Much damaged | Builder, xiv. | - | July | | | 391 | - | | | | | - | 1856 | Addlethorpe Church, | Much damaged | Builder, xiv. | - | | | | 391 | - | July | Lincolnshire | | | - | | | | | - | 1856. | Church of St. | Much damaged | Tomlinson’s | - | July 14| Ebbe, Oxford | | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1856. | Holy Trinity | Much damaged | Builder, xiv. | - | Aug. | Church, Manchester | | 451 | - | | | | | - | 1857. | Parish Church, | Steeple set on | Tomlinson’s | - | May | Wisborough, Sussex | fire | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1857 | Walgrave Church | Damaged | Tomlinson’s | - | | | | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1857. | Wargrave Church, | Pinnacle | Tomlinson’s | - | May | Twyford | destroyed | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1857. | Tower of Windsor | Four tons | Tomlinson’s | - | Aug. | Castle | of parapet | Thunderstorm, | - | | | demolished | p. 167 | - | | | | | - | 1857 | Independent | Set on fire | Tomlinson’s | - | | Chapel, Portsmouth | | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1857. | St. Michael’s | Pinnacle | Tomlinson’s | - | Aug. | Church, Stamford | demolished | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1857 | Trinity Church, | Struck during | Tomlinson’s | - | | Southwark | service | Thunderstorm, | - | | | | p. 167 | - | | | | | - | 1857. | A gasometer at | Struck, and gas | Builder, xv. | - | Aug. | the Chartered Gas | ignited | 488 | - | | Co.’s works, St. | | | - | | Luke’s | | | - | | | | | - | 1858. | The monument to | Slightly injured | | - | July | Dugald Stuart at | | | - | | Edinburgh | | | - | | | | | - | 1858. | Peak Hall, near | Church struck; | Tomlinson’s | - | July | Stoke-on-Trent | roof damaged, | Thunderstorm, | - | | | walls seriously | p. 167 | - | | | fractured, and | | - | | | organ injured | | - | | | | | - | 1862. | Mashbury Church, | Set on fire | Builder, xx. | - | May | Essex | | 391 | - | | | | | - | 1862. | Bampton Parish | Much damaged | Builder, xx. | - | May | Church | | 391 | - | | | | | - | 1862. | Rainham Parish | Damaged | Builder, xx. | - | May | Church, Kent | | 391 | - | | | | | - | 1862. | Tackley (near | Much damaged | Building News, | - | July | Woodstock) Parish | | 1862, p. 77 | - | | Church | | | - | | | | | - | 1863. | Dunoon Church, | Nearly destroyed | Builder, xxi. | - | Feb. | Scotland | | 140 | - | | | | | - | 1863. | St. Paul’s Church, | Considerably | Building News, | - | June | Manchester | damaged | 1863, p. 457 | - | | | | | - | 1864. | St. Mary, York | Slightly damaged | Builder, xxii. | - | Sept. | | | 691 | - | | | | | - | 1865 | St. Lawrence, | Much damaged | Builder, | - | Jan. | Nuremberg, Bavaria | | xxiii. 53 | - | | | | | - | 1865. | St. Mary’s Church, | Much damaged | Builder, | - | July | Stamford | | xxiii. 526 | - | | | | | - | 1865. | St. Botolph | Much damaged | Builder, | - | July | Church, Boston | | xxiii. 526 | - | | | | | - | 1865. | Roman Catholic | Much damaged | Builder, | - | July | Chapel, Colchester | | xxiii. 526 | - | | | | | - | 1867. | Sutton-in-Ashfield | Spire destroyed | Builder, xxv. | - | Sept. | Church, | | 695 | - | | Nottinghamshire | | | - | | | | | - | 1867. | St. Pé-Saint-Simon | Much damaged | Builder, xxv. | - | Sept. | Church, France | | 684 | - | | | | | - | 1867. | Sanzet Church | Set on fire | Builder, xxv. | - | Sept. | | | 684 | - | | | | | - | 1868. | St. Paul’s Church, | Much damaged | Builder, xxvi. | - | May | Little Chester, | | 340 | - | | Derby | | | - | | | | | - | 1868. | St. Stephen’s, | Slightly damaged | Builder, xxvi. | - | June | Southwark | | 433 | - | | | | | - | 1868. | Temporary | Set on fire | Builder, xxvi. | - | June | Congregational | | 433 | - | | Church, Buckhurst | | | - | | Hill | | | - | | | | | - | 1868. | Victoria Tower, | Slightly damaged | Builder, xxvi. | - | June | Houses of | | 416 | - | | Parliament | | | - | | | | | - | 1868. | Morville Church, | Much damaged | Builder, xxvi. | - | June | Shropshire | | 416 | - | | | | | - | 1868. | School, Furze | Much damaged | Builder, xxvi. | - | June | Hill, Brighton | | 416 | - | | | | | - | 1868. | Church, Shanghai | Destroyed | Builder, xxvi. | - | June | | | 416 | - | | | | | - | 1870 | St. Saviour’s, | One pinnacle | Builder, | - | | Southwark | destroyed and | xxviii. 604 | - | | | church damaged | | - | | | | | - | 1870 | Rotherfield Church | Considerably | Builder, | - | | | damaged | xxviii. 604 | - | | | | | - | 1871. | Hethersett Church | Much damaged | Builder, xxix. | - | June | | | 450 | - | | | | | - | 1871. | St. John’s Church, | Slightly damaged | Builder, xxix. | - | June | Bury St. Edmunds | | 450 | - | | | | | - | 1871. | St. Margaret’s | Much damaged | Ann. Reg. p. 72 | - | July | Church, King’s Lynn| | | - | | | | | - | 1871. | Cromer Church | Damaged | Ann. Reg. p. 72 | - | July | | | | - | | | | | - | 1871. | Congregational | Considerably | Scientific | - | Sept. | Church, Terre | damaged | American, xxv. | - | | Haute, Ind., U.S. | | 161 | - | | | | | - | 1872. | St. Mary’s Church, | Set on fire and | Builder, xxx. | - | Jan. | Crumpsall, | destroyed | 51 | - | | Manchester | | | - | | | | | - | 1872. | Baptist Chapel, Wem | Slightly damaged | Builder, xxx. | - | June | | | 511 | - | | | | | - | 1872. | St. Mary’s Church, | Set on fire and | Builder, xxx. | - | June | Beeston, Norfolk | destroyed | 423 | - | | | | | - | 1872. | St. Martin’s | Slightly damaged | Builder, xxx. | - | June | Church, Birmingham | | 423 | - | | | | | - | 1872. | Rainham Church, | Damaged | Builder, xxx. | - | May | Kent | | 391 | - | | | | | - | 1872. | Mashbury Church, | Set on fire | Builder, xxx. | - | May | Essex | | 391 | - | | | | | - | 1872. | Bampton Parish | Much damaged | Builder, xxx. | - | May | Church | | 391 | - | | | | | - | 1872. | Chiddingley Church | Slightly damaged | Builder, xxx. | - | June | | | 484 | - | | | | | - | 1872. | All Saints’ | Slightly damaged | Builder, xxx. | - | June | School, Little | | 484 | - | | Horton | | | - | | | | | - | 1872. | Kibblesworth | Slightly damaged | Builder, xxx. | - | June | Wesleyan Chapel | | 484 | - | | | | | - | 1872. | Brixton Church | Considerably | Builder, xxx. | - | July | | damaged | 603 | - | | | | | - | 1872. | Leigh Church | Severely injured | Builder, xxx. | - | July | | | 591 | - | | | | | - | 1872. | St. Giles, | Slightly damaged | Builder, xxx. | - | Aug. | Cripplegate | | 629 | - | | | | | - | 1872. | Holy Trinity | Severely injured | Builder, xxx. | - | Aug. | Church, Windsor | | 610 | - | | | | | - | 1872. | Dundonald Parish | Spire and roof | | - | Sept. | Church | damaged | | - | | | | | - | 1873. | Parish Church, | Slightly damaged | Builder, xxxi. | - | April | Cromer | | 331 | - | | | | | - | 1873. | Martham Church | Much damaged | Builder, xxxi. | - | April | | | 331 | - | | | | | - | 1873. | Ripponden Church | Much damaged | Builder, xxxi. | - | Nov. | | | 875 | - | | | | | - | 1873. | Industrial School, | Set on fire | Builder, xxxi. | - | Nov. | Mosbank, Glasgow | | 875 | - | | | | | - | 1874. | Chesterfield Church | Slightly damaged | Builder, | - | July | | | xxxii. 613 | - | | | | | - | 1874. | Christ Church, | Slightly damaged | Builder, | - | July | Salford | | xxxii. 613 | - | | | | | - | 1874. | St. Luke’s, | Set on fire, | Builder, | - | July | Homerton | much damaged | xxxii. 613 | - | | | | | - | 1874. | General Post | Slightly damaged | Builder, | - | July | Office, St. | | xxxii. 613 | - | | Martin’s le Grand | | | - | | | | | - | 1874. | Military Prison, | Slightly damaged | Builder, | - | July | R.A. Barracks, | | xxxii. 613 | - | | Woolwich | | | - | | | | | - | 1874. | Free Church of | Completely | Builder, | - | July | Braco, Perthshire | destroyed | xxxii. 613 | - | | | | | - | 1874. | Ayot St. Peter | Completely | Ann. Reg. p. 70 | - | July | Parish Church, | destroyed | | - | | Herts | | | - | | | | | - | 1875. | Chester le Street, | Spire | Newcastle | - | June | Durham | considerably | Chronicle, | - | | | damaged | June 16th | - | | | | | - | 1875. | West End Church, | Spire destroyed | Builder, | - | June | near Southampton | | xxxiii. 586 | - | | | | | - | 1875. | London and South | Destroyed | Builder, | - | June | Western Railway | | xxxiii. 586 | - | | Co.’s tall | | | - | | chimney shaft at | | | - | | Southampton | | | - | | | | | - | 1875. | Barthomley Church, | Damaged | Daily paper | - | July | near Crewe | | | - | | | | | - | 1875. | St. Mary’s Church, | Much damaged | Builder, | - | July | Birkenhead | | xxxiii. 632 | - | | | | | - | 1875. | St. Nicholas | Much damaged | Builder, | - | Aug. | Church, | | xxxiii. 783 | - | | Blundellsands | | | - | | | | | - | 1876. | Cottingham Church, | Set on fire | Daily paper | - | Mar. | near Hull | | | - | | | | | - | 1876. | Snettisham Church | Considerably | Daily paper | - | April | | damaged | | - | | | | | - | 1876. | Shotts Parish | Steeple | Daily paper | - | April | Church | destroyed | | - | | | | | - | 1876. | Union Workhouse, | Roof set on fire | Daily | - | July | Retford | | Chronicle, | - | | | | July 25 | - | | | | | - | 1876. | Bishopstone Church | Considerably | Lloyd’s Weekly | - | July | | damaged | News, July 23 | - | | | | | - | 1876. | Wilmcote Church | Considerably | Lloyd’s Weekly | - | July | | damaged | News, July 23 | - | | | | | - | 1876. | St. Peter’s | Considerably | Sunday Times, | - | July | Church, | damaged | July 23 | - | | Stratford-on-Avon | | | - | | | | | - | 1876. | Market Hall, | Damaged | Daily | - | July | Doncaster | | Telegraph, | - | | | | July 24 | - | | | | | - | 1876. | Grey Friars Tower, | Considerably | Daily paper | - | Sept. | King’s Lynn | damaged | | - | | | | | - | 1877. | Catholic Church, | Six persons | Globe, May 31, | - | May | Wieschen, Poland | killed and | 1877 | - | | | seventy | | - | | | seriously | | - | | | injured | | - | | | | | - | 1877. | All Saints Church, | Much damaged | Builder’s | - | May | Stand Whiteland, | | Weekly | - | | Lancashire | | Reporter, May | - | | | | 25, 1877 | - | | | | | - | 1878. | Sir David Baird’s | Almost entirely | Daily | - | May | monument, | destroyed | Telegraph, May | - | | Perthshire | | 30 | - | | | | | - | 1878. | St. Luke’s Church, | Damaged | Daily paper | - | June | Hackney | | | - | | | | | - | 1878. | Wesleyan Chapel, | Damaged | Daily paper | - | July | Southampton | | | - | | | | | - | 1878. | Free Methodist | Damaged | Daily paper | - | July | Church, Tamworth | | | - | | | | | - | 1878. | St. Jude’s Church, | Much damaged | Daily paper | - | July | Bethnal Green | | | - | | | | | - | 1878. | Church of the Holy | Considerably | The Times, | - | July | Nativity, Knowle | damaged | July 27 | - | | | | | - | 1879. | Henlow Church, | Considerably | The Times, | - | April | Bedfordshire | damaged | April 18 | - | | | | | - | 1879. | Laughten-en-le- | Considerably | The Times, May | - | May | Morthen Church | damaged | | - | | | | | - | 1879. | St. Marie’s | Set fire to the | Weekly | - | June | Church, Rugby | woodwork | Dispatch, June | - | | | | 8 | - | | | | | - | 1879. | Clevedon Market | Very much | Daily | - | June | House, nr. Bristol | damaged | Chronicle, | - | | | | June 10 | - | | | | | - | 1879. | Parish Church, | Burnt to the | Norwich paper | - | Aug. | Wells, Norfolk | ground | | - | | | | | - | 1879. | Cromer Church | Pinnacle damaged | Daily paper | - | Aug. | | | | - | | | | | - | 1879. | St. Bride’s | Slightly damaged | Daily paper | - | Aug. | Church, Stepney | | | - | | | | | - | 1879. | Sanctuary of | Damaged. | Electrician, | - | Sept. | Madonna de | Several persons | Sept. 6 | - | | Valmala, Valmala | killed | | - +---------+---------------------+------------------+-----------------+ - - -_POWDER MAGAZINES STRUCK BY LIGHTNING._ - - +-------+------------------------------+-----------------------------+ - | DATE | BUILDING | DAMAGE | - +-------+------------------------------+-----------------------------+ - | 1732. | Gunpowder Magazine at | Exploded. City laid in | - | Oct. | Compost Major, Portugal | ruins; above 1,000 people | - | | | injured | - | | | | - | 1739. | Bremen | 1,000 houses destroyed | - | Sept.| | | - | | | | - | 1763. | Fort Augusta, Jamaica, | Great number killed; much | - | Nov. | powder magazine, containing | damage to property | - | | 2,850 barrels of powder | | - | | | | - | 1769. | Brescia Magazine, containing | Exploded; 3,000 persons | - | Aug. | 207,600 lbs. of powder | killed | - | | | | - | 1769 | Venice | 400 persons killed | - | | | | - | 1772. | Chester | Great damage to property; | - | Nov. | | many lives lost | - | | | | - | 1773 | Cambray | 18 people killed; several | - | | | houses greatly damaged | - | | | | - | 1773 | Abbeville | 150 persons killed; 100 | - | | | houses destroyed | - | | | | - | 1780. | Malaga Gunpowder Magazine | | - | Aug. | | | - | | | | - | 1782. | Sumatra Gunpowder Magazine | | - | Mar. | | | - | | | | - | 1785. | Tangiers Gunpowder Magazine | | - | May | | | - | | | | - | 1807. | Luxembourg Gunpowder Magazine| About 12 tons of powder | - | June | | exploded | - | | | | - | 1808. | Venice Gunpowder Magazine | | - | Sept.| | | - | | | | - | 1829. | Navarino Gunpowder Magazine | 17 killed; 78 wounded | - | Nov. | | | - | | | | - | 1840. | Bombay Gunpowder Works Dum | | - | June | Dum Gunpowder Magazine | | - | | | | - | 1843. | Sicily, Puzzaloni Gunpowder | | - | April| Magazine | | - | | | | - | 1843. | Spain, Gaucin Gunpowder | A number of persons | - | April| Magazine | killed; church and 200 | - | | | houses destroyed | - | | | | - | 1853 | Hounslow Gunpowder Magazine | | - | | | | - | 1855. | Firework manufactory, | Exploded | - | Oct. | Liverpool | | - | | | | - | 1856. | Rhodes Gunpowder Magazine | A considerable number of | - | Nov. | | persons killed, and a | - | | | large portion of the town | - | | | laid in ruins | - | | | | - | 1857. | Bombay, Joudpore | About 1,000 persons | - | Aug. | | killed; 500 houses | - | | | destroyed | - | | | | - | 1878. | Bruntcliffe Colliery, near | Exploded | - | Aug. | Leeds; powder magazine, | | - | | containing about one ton of | | - | | powder | | - | | | | - | 1878. | Pottsville, Pa., U.S.; a | Exploded; 3 persons | - | Aug. | powder magazine containing | killed, several injured; | - | | 25,000 lbs. of powder | many houses wrecked | - +-------+------------------------------+-----------------------------+ - - - - -CHAPTER XV. - -THE EARTH CONNECTION. - - -To dwell too largely upon the importance of leading all lightning -conductors down into moist earth, or, as technically called, ‘good -earth,’ would be scarcely possible. It would perhaps not be too -strong an expression to say that the part of the conductor above -ground is a mere appendage to that under ground, the essential -function of the whole apparatus--that of dispersing the electric force -harmlessly--being accomplished by the subterranean portion. The clear -understanding of Benjamin Franklin perceived this at the outset; -but after him it seemed as if forgotten for a long time, and the -result showed itself in numerous disasters that occurred to buildings -protected with conductors, which brought the latter into disrepute with -many persons. While, no doubt, in many instances the cause of these -disasters was in the bad application of the conductors themselves, -their defective character, or their feebleness, still in the great -majority the underground connection may be taken to have been in -fault. It may be laid down as an absolute certainty that a really good -conductor--say, a copper rope from five-eighths to three-quarters of an -inch in thickness--cannot possibly fail to carry off the electric force -if the lower part reaches moist earth or water. Probably, in nine cases -out of ten, whenever a building provided with a conductor is struck by -lightning, it is for want of ‘good earth.’ - -Franklin’s own ideas were very clear on the subject. He laid them -down at various times, more particularly when residing in England, -during the years from 1764 to 1775, as colonial agent for Pennsylvania. -During the latter part of this period he took an active interest in the -proceedings of the Royal Society; and this learned body being requested -by the Government to give advice regarding the best protection against -lightning that could be provided for the great powder magazines at -Purfleet, he was nominated into a committee with three other members, -William Watson, H. Cavendish, and J. Robertson. The committee drew up -a report, dated August 21, 1772, signed by all the members, but known -to be written by Franklin alone. Dwelling strongly on the importance of -the underground connection, Franklin says in this report: ‘In common -cases it has been judged sufficient if the lower parts of the conductor -were sunk three or four feet into the ground, till it came to moist -earth; but this being a case of great consequence, we are of opinion -that greater precaution should be taken. Therefore we would advise that -at each end of each magazine a well should be dug, in or through the -chalk, so deep as to have in it at least four feet of standing water. -From the bottom of this water should rise a piece of leaden pipe to, or -near, the surface of the ground, where it should be joined to the end -of an upright bar.’ Franklin then goes on to recommend the usefulness -of having even more wells than the two, so as to avoid any possibility -of failure in protecting the powder magazines. ‘We also advise,’ he -says in his report, ‘in consideration of the great length of the -buildings, that two wells of the same depth with the others should be -dug within twelve feet of the doors of the two outside magazines--that -is to say, one of them on the north side of the north building, and the -other on the south side of the south building, from the bottom of which -wells similar conductors should be carried up.’ It is not on record -whether these recommendations were adopted by the Government, but it -seems likely that this was the case, as the fear of explosion of powder -magazines through a stroke of lightning was very great at the time. Not -long before, a magazine had been so destroyed at Brescia, in Italy, -with the appalling result of a considerable part of the city being laid -in ruins, burying many hundreds of persons. The destruction of the -Brescia powder magazine, like all similar events, had, it is scarcely -necessary to say, its due effect in spreading a desire for lightning -conductors, fear doing what was not effected by foresight. - -Whether or not the English Government made the wells recommended by -Franklin for the Purfleet powder magazine, it is certain that the -sound advice given was not largely followed. On the contrary, there -grew a generally prevailing laxity in regard to the indispensableness -of a good underground connection, which led to numerous accidents. -They were seldom, however, ascribed to the right cause, others being -sought instead--such as particular forms of conductors and the -insufficient length of those phantoms called ‘reception-rods,’ which, -as many thought, could never be made high enough, in order to ‘draw -the electric fluid’ from the clouds. Height was sought where nothing -but depth was required, and the same unsightly rods, towering high -above buildings, would have very effectually carried off the electric -forces if brought from the top to the bottom of the conductor, being -taken out of the air and stuck into the earth. Still, there were -not wanting philosophical minds impressed with the truth that no -lightning conductor can discharge its functions unless rooted in -moisture, and who not only knew it, but did their best to spread this -knowledge in all directions. One of these philosophers, a singular -character in his way, was a German clergyman, the Rev. Dr. Hemmer, -who lived at Mannheim, on the Rhine, at the end of the last century. -Taking the deepest interest in Franklin’s great discovery, he made -many experiments with lightning conductors, which brought him to the -conviction that the electric force, in its chief tendency, seeks -the mass of water on the globe, and that where this is not on the -surface, it must be guided to it to become harmless. Consequently, he -recommended to sink the conductor invariably deep into the ground, so -as to reach water, and to subordinate everything else to this prime -necessity. To make the use of lightning conductors as general as -possible, Dr. Hemmer not only wrote a number of little books, which -he liberally distributed, but travelled about through many parts of -Germany, instigating the authorities to place conductors on all public -buildings, and the people to set them up over their own houses. Holding -that the earth connection was everything, he advocated simply to dig -a hole in the ground till water or very moist earth was reached, and -to stick a small iron bar, wrapped in lead to prevent rust, into it, -running up the roof. The bar any village blacksmith could forge, and -the hole any man or boy could dig, thus making the absolute cost of the -conductor under this arrangement very trifling. Dr. Hemmer was right, -no doubt, in his main argument, and most successful in spreading the -knowledge of lightning conductors, while he was able to boast that not -one of all the number he had set up had ever failed. However, he lived -in an age when as yet water and gas pipes were unknown, and iron, or -any other metal, scarcely entered into the construction of buildings. -Given a leaden roof and a network of metal tubes, and Dr. Hemmer’s -small iron rod could scarcely be expected to do its work of protection. - -Together with Dr. Hemmer in Germany, Professor Landriani, of Milan, -drew attention to the paramount importance of a perfect earth -connection. He made it his special business to investigate cases in -which buildings with lightning conductors had been struck, and was able -to show in nearly every instance that it had been for want of ‘good -earth.’ A very striking case, which ought to have brought conviction -of the truth to all investigators of the subject, occurred in Genoa in -1779. The church of St. Mary in this city, standing in a very elevated -position, had been frequently struck by lightning, sometimes as often -as twice in one year, and it was noticed that the electric force always -followed precisely the same path, running along a certain portion -of masonry, partly secured by iron hoops, and finally demolishing a -wall at the bottom to get into the earth. At last, in November 1778, -a conductor, made of the most approved design, was placed over the -church, but, to the great surprise of the scientific men who had -superintended the work, the lightning fell once more upon the building -in the month of July of the following year, again following the old -path it had constantly taken before, and causing absolutely the same -damage as previously, even to the knocking out of certain portions of -the wall nearest the ground. Naturally, the event caused widespread -interest, leading to the closest examination of the church of St. Mary -by several experts, among them Professor Landriani. He had no great -trouble in discovering both the causes of the path of the lightning -having always been the same when falling upon the church, and of the -edifice having been struck again in the same manner when provided with -a lightning conductor. Being a somewhat peculiar structure, consisting -in part of hewn stones held together with iron cramps, there was a -large quantity of metal both in and outside; and it was found that -the path of the lightning had always been precisely in the direction -where the metal offered the greatest continuity, leaping over the short -intervals that existed by destroying the stone, and finally getting -into the ground to a place where there was always a collection of -water by knocking down a wall. If this accounted satisfactorily for -the former accidents, that which took place when a conductor had been -placed was not much more difficult of explanation. Professor Landriani -found that though the conductor itself was very good, it was useless -simply by having its roots in hard rock instead of moist ground. On -the one side of St. Mary’s Church there was a rill of water rippling -down from the hills, and forming a small pool near the church, while -on the other was the hard rock. It was into a crevice of the latter -that the conductor had been laid, thus leaving the electric force to -seek its old path into the water along the iron bars, which, although -disjointed, formed a far better road to earth than the planned road. -It was a convincing proof of the supreme necessity of a good earth -connection. Still, a long time yet was to elapse before conviction -became general. - -Probably, the matter was more studied by Italian scientific men than -any others, the study of electricity having always been a favourite -pursuit in that country; yet there, too, the matter was not understood -till quite recently. This is proved by a letter of the celebrated -astronomer and meteorologist, Father Secchi, addressed to the French -scientific journal ‘Les Mondes,’ in October 1872, in which he tells -the story of an accident that befel a building protected by lightning -conductors set up under his own direction, the earth connection being -made after rules laid down by Professor Matteucci, considered the -leading authority on the subject. The letter of Father Secchi, though -of some length, is given here entirely, both on account of the great -fame of the writer, but recently deceased, and because it throws a -flood of light on some of the most important points connected with the -art of designing and applying lightning conductors. - -‘Eight years ago,’ says Father Secchi, writing, as just mentioned, in -1872, ‘some lightning conductors had been erected under my direction -on the cathedral and on the Bishop’s palace of Alatri, situated at -the summit of the Acropolis of that town, which, by its elevated and -solitary position, was exposed to frequent ravages from storms. It was -not long ago that a flash of lightning demolished a great part of the -belfry, and damaged the organ of the church. In the erection of this -lightning conductor there arose a great difficulty proceeding from the -nature of the soil, which at the depth of some centimetres turns out to -be entirely of solid calcareous rock. - -‘In order to remedy this defect, that part of the conductor which -enters the ground has been made very long, more than 4 metres [13 -feet], and has been provided with a great many couples of points, 5 -centimetres [2 inches] broad, 5 millimetres [⅛ inch] thick, indentated -on the edges, with the addition of a thick copper wire twisted among -the same points, to help to multiply the points of contact between the -rod and the carbon. The foot of the lightning conductor is entirely -of copper. The rod is also of copper up to a metre [3¼ feet] above -the ground; and there is joined to it the iron conductor, in the -ordinary receptacle made in the heart of the wall, to preserve it from -disturbances of the inferior parts. The ditch into which the foot of -the lightning conductor was sunk is 5 metres [·16 feet] long, and -half-a-metre [1⅝ feet] wide, and it was dug into the ground as far -as to touch the roots of some neighbouring trees, from which point -upwards a layer of cinders was placed, covering the greater part of the -ditch. Thus the surface of contact between the metal and the carbon, -and of the latter with the soil, was such that one would have supposed -it to be more than sufficient, while the presence of trees, although -they were not very large, made it highly probable that the ground did -always contain sufficient moisture. Moreover, as the edifice had two -culminating points--namely, the belfry and the raised back portion of -the choir--two rods were placed on them, each having an independent -connection with the earth, so that, in the case of a discharge on one -of the points, the electric force might find two ways in its course -towards the earth. - -‘These arrangements produced, on the whole, a good result, since, -although the edifice was struck at least four times after conductors -had been placed on it, it suffered no damage of any kind. Nevertheless -a very curious accident, highly interesting as a scientific study, -happened on October 2. Early on the morning of this day several flashes -of lightning fell down from the clouds during a terrific storm, -which lasted over two hours. The belfry was struck at first by weak -discharges twice; but the third flash was so appalling in its strength -as to terrify the whole town below. The injuries it caused were not -great, still they seemed to me to be extremely noteworthy. But before -I describe them I must give some necessary details as to place and -position of the lightning conductor. - -‘It so happened that four years after the erection of the conductor -a line of pipes was laid down to carry water to the towns of Alatri -and Ferentino, passing at a short distance from the belfry of the -cathedral. The lightning conductor was not placed in communication with -the pipes, because it seemed established, from previous experiments -and observations, that it was needless to do so, the ground containing -apparently sufficient moisture, the head of the waterworks being close, -and there existing also a running fountain. I was not asked at the time -whether it was necessary to establish this communication, but, had the -question been put to me, I should probably have answered it in the -negative, considering, from what I then knew, the work as superfluous. -That I was in error then as to the necessities of a perfect underground -connection is shown by what happened during the great storm in the -early morning of October 2. The heavy flash of lightning before -referred to did not go its appointed path underground, but passed off -into the waterworks, with the following results:— - -‘1. It made in the earth a perfectly rectilinear excavation, which, -from the lower part of the conductor, went to the tube of the -waterworks running to Ferentino, and in traversing the wall destroyed -the angle of that structure. The earth of the ditch thus dug was -disposed regularly to right and left with great symmetry. The length -of the ditch was about 10 metres, the depth about 70 centimetres [28 -inches]. - -‘2. The lightning struck the water-pipe of Ferentino, broke it -completely, throwing the pieces to a distance of about 80 centimetres -[32 inches]. The lead which soldered the joint of the broken tube with -the tube beyond was found melted. In consequence of this rupture the -water ceased flowing to Ferentino, and poured into the waterworks. - -‘3. Another part of the discharge spread itself by the pipe which goes -to Alatri, and traversing the reservoir threw to a great distance -some wooden plugs which stopped up the discharging tubes, the plugs -being forcibly hammered in. It arrived at the town in a tank, where it -damaged and twisted in a strange manner a leaden slab which was in the -tank, made some other little injuries, and finally left the trace of -its passage at the spouts of the public fountain. - -‘4. The point of the lightning conductor was examined, and it was found -very blunt; it was found impossible to unscrew it, and it could not be -removed without breaking the screw. It was found broken to a length of -more than 3 centimetres [1¼ inch], and the section of fusion was nearly -flat, as though it had been cut. The gold of the gilding had nearly all -disappeared. In the church, and in the edifice which is attached to -it, no injury was detected. These facts appear to me important both as -regards practice and theory: in respect to theory, because they give -an idea of the quantity and of the immense force of the discharge. -The melting of the point down to a section 1 centimetre [½ inch] in -diameter proves that it would have been melted down much further if it -had been slighter. It is not prudent, then, to use very slender points; -it is best that they should thicken quickly. - -‘The excavation of the ditch at the foot of the lightning conductor -could not be the direct effect of electricity, but would be the result -of the sudden evaporation of the moisture of the ground, generating -steam, and forming, as it were, a mine. - -‘The breaking of the tube is most singular. It seems to me that it -can with difficulty be attributed to the mechanical shock of the -electricity itself. As the lead which united the broken tube to the -one beyond was found melted, it is evident that, in spite of the water -which flowed in this tube, it was raised to an enormous temperature in -the place where it was struck, and probably it was the instantaneous -evaporation of the water inside which caused the breaking of the tube. - -‘But the most singular fact, in a certain respect, is what was observed -in the tube which descends to Alatri--that is to say, the alteration -in form of the leaden slab. The little interruption which necessarily -exists in this tank between the conducting-pipe and the metallic -receptacle evidently gave occasion for a discharge by a flash, and, in -consequence, for an explosion of steam. But we see at the same time -by that that the distance traversed in the tube from the building to -the slab, a distance of more than 200 metres [650 feet], in which the -pipe is buried underground, did not suffice for the charge to lose -itself in the ground, although during the passage it had to cross the -reservoir, and might there have distributed itself. Our surprise is -still greater when we reflect that it was only part of the discharge, -since the greater portion had to flow by the water-pipe of Ferentino, -which was the first struck in a direct manner, and that these pipes -are joined together with lead. The quantity of electricity must have -been enormous, in order to be able to have so much force and to run -another 300 metres [975 feet] to reach the public fountain, and leave -its traces there. A circumstance which deserves attention is, that this -storm took place after a long and constant drought; and consequently -the earth was less moist, and could offer little facility for -dispersion. - -‘These cases are not so rare among us as one might suppose. Not very -long ago, at Lavinia, a flash of lightning destroyed a great part of -the belfry, passed to the bell, broke and melted it in its passage in -such a manner that the metal had run away like wax. I do not believe -this breakage of the bell to have been a mechanical effect of the -lightning in a rigorous sense, for the bell could have been broken by -the instantaneous expansion produced by the heat at the point of the -passage, an expansion which had had no time to disperse, as a glass -vase breaks when touched with a red-hot iron. - -‘Let these facts come about how they may, they enable us to see that it -is necessary to devote great attention in the erection of lightning -conductors, that we must allow them a large surface for discharge, _and -that there can never be too much of it_. The surface of the foot of -our lightning conductor was certainly superior to what has been judged -sufficient by Matteucci for the discharges of telegraphic conductors, -and yet it has not sufficed. Further, it is a confirmation of the -necessity of making the neighbouring metallic masses communicate, and -especially with water and gas-pipes.’ - -From out of the almost endless number of cases in which lightning -conductors failed for want of a good earth connection, another one or -two may be given, illustrated as having happened quite recently in -England, and as such showing, in a very striking manner, in what a -neglected state the knowledge of the subject still is at this moment. -A thunderstorm passed over the town of Clevedon, Somersetshire, in the -afternoon of March 15, 1876, and a flash of lightning fell upon the -steeple of Christchurch, provided, as was generally thought, with a -most efficient conductor of recent construction, made of good copper -rope. What happened is graphically and minutely told in a letter -addressed to the ‘Journal of the Society of Telegraph Engineers,’ by -Mr. Eustace Buttor, of Lewesfell, near Clevedon. ‘There was but a -single flash,’ Mr. Buttor relates, ‘which appeared to many observers -to travel horizontally through the air. However, the lightning passed -down the lightning conductor of Christchurch. The flag-staff, about -100 feet high, and the four pinnacles, about 90 feet high, have each a -conductor, the flag-staff having the usual conical point, the pinnacles -having the copper rope attached to their vanes. The five copper ropes -unite inside the tower in the neighbourhood of the clock. Lower down -the conductor passes through a slanting hole to the outside, and for -the lowest 12 feet is encased in a pipe. On reaching the ground it -passes into a dry freestone channel for about a dozen feet, and then -dips down into the drain which carries rain-water from the roof. As no -rain preceded or accompanied the flash, it may be presumed that _the -drain was dry_. - -‘The protector is copper throughout, and, with the exception of the -termination, seems to have been carefully and efficiently placed. -The diameter I estimate to be half-inch, or it may be a trifle more. -Just at the point where it leaves the pipe and enters the ground, the -electric charge left it, dashed through three feet or more of solid -wall supporting the tower, in order to reach the gas-meter inside, then -it passed safely along the gas-pipe. The cavity made was considerable, -but very irregular. I was unable to ascertain when the workmen were -engaged in repairs, and therefore cannot give their estimate of the -weight of stone displaced, but it must have been many hundredweights, -though only a few pounds were actually thrown out on to the path, or -inside into the vault. A large quantity of stone was pulverised, and -the whole gave one the idea of the explosion of a charge of gunpowder -under great compression. In a house about 100 yards from the church, -the inmates felt the shock intensely, but did not know that the house -had been touched. Some hours after, however, on going to turn on the -gas, a hissing noise was heard, and a hole was found in the composition -gas-pipe, about five-eighth inch diameter, just where the pipe passed -within an inch of a water-pipe. The lightning must have come along -the main from the church gas-pipe to this house, and then passed to -the water-pipe as the readiest way to moist earth. The whole soil in -the neighbourhood is mountain limestone, very dry. There is not the -slightest evidence of displaced plaster, or any other sign of the -passage of an electrical discharge through the house.’ There need be -little comment on the facts stated in this letter, notable though they -are. It is the old delusion that a lightning conductor need be brought -down underground only, and that then all is right. In this case, those -who protected Christchurch, Clevedon, thought it quite sufficient to -bring the conductor down into a drain-pipe carrying rain-water from the -roof, without reflecting for a moment that an earthenware drain-pipe -would insulate the conductor from ‘earth.’ A similar instance came -under the writer’s notice about a year ago. One of the pinnacles -of Cromer Church, in Norfolk, was struck by lightning, although -fitted with a conductor on one of the pinnacles. On examination it -was discovered that the earth terminal had been inserted into an -earthenware drain. - -It is not very easy to give exact prescriptions as to the best manner -in which the underground connection should be effected. The means -vary entirely with the circumstances, and the matter should in all -cases be intrusted to an expert. Simple as is the whole theory of -lightning protection, consisting in nothing else but laying a good -metallic path from the top of a building down into moist earth, as an -unfailing path for the electric force, the practical execution of it -is not the less often very complicated. It is especially so as regards -the most important of points, that of the underground connection. Of -course, wherever there is running water at hand, a river, or even a -tiny stream that never dries, the matter is easy enough, but as in the -great majority of buildings to be protected such water does not exist, -the solution of the question becomes more difficult, and frequently -one of the greatest perplexity. It tends even to be more and more so -in consequence of the progress of sanitary arrangements under which -towns and villages are ‘drained’ until the soil has been made as dry -as a rock. Immense as the benefit is to public health, it is, like all -benefits, attended by certain drawbacks. One of these certainly is a -greater danger from lightning. It is often proposed by builders to -use the drain-pipes themselves in making ‘good earth’ for lightning -conductors, but the fallacy of this recommendation need scarcely be -exposed, seeing that these conduits are generally made of earthenware, -as happened when Christchurch, Clevedon, was struck by lightning. - -While broad rules cannot be laid down, still it may be affirmed that a -good earth connection, sufficient to carry off the heaven’s electric -discharges, may always be obtained by either of two means. The first, -and in all cases most preferable, is to lay the conductor deep enough -into the ground to reach permanent moisture. When this exists in a -considerable mass, the single conducting rope, touching it, will be -quite sufficient; but when the quantity is deficient, or doubtful, it -will certainly be advisable to spread out the rope, so as to run in -various directions, similar to the root of a tree, likewise in search -of moisture. There are various modes of accomplishing this, shown in -figs. 46 and 47. - -[Illustration: Fig. 46.] - -[Illustration: Fig. 47.] - -A variety of methods have been proposed for the dispersion of the -electric force underground where the soil contains little or no -moisture, except at great depths, to be reached only by a vast amount -of labour and expenditure. In France, the system most generally adopted -in these cases is to place at the bottom of the underground connection -an apparatus, made either of iron or copper, shaped somewhat in the -form of a harrow, and to embed it thickly in charcoal. Fig. 48 will -illustrate this system of earth connection. - -[Illustration: Fig. 48.] - -The apparatus is as simple as it may be useful, and the more so, of -course, the thicker the mass of charcoal in which it is embedded. But -it may be doubted whether it is sufficient to make ‘good earth’ under -all circumstances. Perhaps it will do so in ninety-nine cases and fail -in the hundredth. The amount of electric force discharged in ordinary -thunderstorms does not seem to vary much, and, according to all -observations, such an artificial connection as this of the charcoal bed -is sufficient to disperse it safely beneath the surface. But now and -then there come storms of extraordinary violence, or, in other words, -extraordinary accumulations of atmosphere electricity, which demand -precautions such as are not fulfilled by the subterranean harrow, -however thickly embedded in charcoal, or, as oftener done, in gas coke -or cinders. It is certain that there have been cases in which buildings -with otherwise excellent conductors, but provided with such an -artificial earth connection, have been damaged by lightning. However, -it may be stated, as the net result of all observations and known facts -upon the subject, that small private houses can be well protected by -this means against lightning, but that the system cannot be recommended -as absolutely safe for large edifices and public buildings. - -To protect any structure of great extent, it is absolutely necessary to -bring the conductor, or conductors, deep enough into the earth to reach -water. It is all the more indispensable with modern buildings, as they -contain large masses of metal, not only in gas and water-pipes, but -often in staircases and iron columns, towards which the electric force -has the strongest tendency to direct itself unless drawn to the earth -by an immediate and unfailing connection with the great sheet of water -below its surface. It is considered by German electricians that there -is no necessity, if a large edifice has a number of conductors, to let -each have a separate earth connection; it is quite sufficient to bring -them all into one, provided only that this is absolutely perfect at all -seasons and under all circumstances. Fig. 49 will show how this can be -done. - -[Illustration: Fig. 49.] - -It will be seen that for the protection of this edifice there are six -conductors, with four elevated points marked A, B, C and _c_. Two of -these points, A and C, expand from the roof to the ground into double -conductors, so as to protect the sides of the building against possible -lateral discharges of lightning, and all the six conductors meet a -little below the surface in the earth connection prepared for them. To -form this one connection, either by digging or boring, may sometimes -be costly, but whether the expenses be more or less, the protection -against lightning thus effected will be so absolute as to be invaluable. - -In a similar manner as the large edifice, with its many gables, a -church may be fitted with lightning conductors. Fig. 50 scarcely needs -much explanation. - -[Illustration: Fig. 50.] - -There is one thing, however, regarding churches, that must be well -borne in mind in establishing their protection against lightning. -Besides containing great masses of metal, in bells, organs, and other -contents, they are frequently placed in high situations, exposed to -the most violent discharges of the electric force. It often happens -also that they stand on rocky ground, with the subterranean waters -far below the surface. To ensure absolute protection under these -circumstances, it is indispensable to connect the conductors with -water, wherever it is to be found, by a solid channel, into which -the copper rods may run, if possibly some distance below the surface -of the earth. The form such a channel may take is indicated on the -engraving. It will be seen that the protection against lightning -indicated here is not only for the church, but the adjoining parsonage, -the conductors spreading over both, with points on the most prominent -and exposed places. It would be possible to carry out this principle -in ensuring the protection of a whole block of private buildings. -German electricians think that one channel or well, sufficiently broad, -leading from the surface of the earth to layers always moist, or to -perennial springs, would suffice to carry the electric force discharged -upon a hundred conductors, and all the easier as it would be impossible -that many would be struck at one and the same time by lightning. -Perhaps some such arrangements will be made in the future, when both -houses and towns are built upon a more systematic plan than is followed -at the present time. - -If, as a rule, one channel of underground connection is amply -sufficient for the protection of even the largest buildings, there -may be cases in which it is indispensable to spread the conductors -into several directions. It may be laid down, broadly, that when -there is water to be reached, the one channel is sufficient, but that -when this is not possible, or expedient, more lines of underground -connection must be formed. Fig. 51 may serve to illustrate a case of -the latter kind. It shows a powder-magazine, partly above and partly -underground, standing on dry soil, with trees in the neighbourhood, -likely to add to the danger of atmospheric discharges of electricity, -and with no stream, or permanent moisture, into which to guide them. -Nothing remains, under these circumstances, to ensure safety, but to -multiply the lines of underground connection to the utmost extent. To -add to the facility of the dispersion of the electric force, the main -channels may be filled with charcoal, broken coke, or cinders, and if -large quantities of these substances can be placed in one or two pits, -it is possible to make thus an artificial connection as nearly as can -be responding to ‘good earth.’ Still, it must never be forgotten that, -absolutely, ‘good earth’ in reference to lightning conductors means -moisture, or water. - -If permanent moisture cannot be obtained and iron water-mains are -within reach, it is desirable to connect the ground terminal with them -by means of good solder, as from the large mass of metal they generally -form very good ‘earths.’ - -[Illustration: Fig. 51.] - -In giving directions, or rather suggestions, about the design and -application of conductors, and, what is most important in regard to -them, their connection with the subterranean mass of waters, the -idea that persons may construct their own conductors is left aside -altogether as absurd. It is a good old proverb which says that a man -who is his own lawyer is certain to lose his cause; another has it -that a man who is his own doctor is sure to succumb to his illness. -With regard to the setting-up of lightning conductors, it is precisely -the same. Simple enough as is the theory of ‘drawing lightning’ from -the clouds, the practical execution of it is, as mentioned more than -once, not a little complicated. The formation of the underground -connection, in particular, is a matter requiring very great experience, -and very frequently one of the utmost difficulty. Vast sums of money -are often thrown away needlessly in making a connection which in the -end proves useless, while, on the other hand, a trifling addition to -the expenditure in setting-up a conductor would procure its efficiency, -not attained simply from want of ‘good earth.’ A recent writer on -lightning conductors whimsically, yet with much truth, expresses it by -remarking that ‘people spend money upon gilded points on the top of -the house, while they ought rather to sink it in water at the bottom.’ -Undoubtedly, the efficiency of conductors lies, even more than at the -top, on ‘the bottom.’ The earth connection may be called ‘the alpha and -omega’ of lightning protection. - - - - -CHAPTER XVI - -INSPECTION OF LIGHTNING CONDUCTORS. - - -There is one subject in regard to the proper protection of buildings -against the destructive effects of lightning which is generally -overlooked, at least in this country, to a really surprising degree. -It is the necessity that lightning conductors, once put up, should be -regularly inspected, to see if they are in good order, so as to be -really efficacious. That this is very rarely done, is one of the main -reasons why accidents by lightning sometimes occur in places nominally -protected by conductors. The neglect is the more astounding, as one -would think that all intelligent persons, whose knowledge prompted them -to see the wisdom of protection against lightning, would likewise come -to the conclusion that the scientific apparatus set up to effect it -required occasional repairs, such as the clocks in their houses and the -buildings themselves. But such is very far from being the case. It is, -perhaps, not too much to assert that at present not one in a thousand -persons who have gone to the expense of protecting their houses by -lightning conductors make the protection complete, at a merely nominal -cost, by providing a regular--say, annual or bi-annual--inspection. - -The causes which necessitate such inspection are numerous. In the first -instance, there is the constantly acting influence of wind and weather -upon those parts of the conductor which are above earth. Wonderful -as is the simple machinery devised by Franklin which conducts the -mysterious electric force from the clouds into the ground, depriving -it of its destructive power, it is, after all, but a feeble thing in -itself, and necessarily so. The upper terminal of the conductor--what -the Germans call the ‘reception rod,’ and the French the ‘tige,’ or -stem--cannot be very thick without becoming unsightly, and, as regards -large public buildings, destroying their architectural effects; while -the rope, or ribbon, running to the ground must, for the same reason, -as well as that of cost, be of comparatively small diameter. Subject -to the constant effects of moisture, to wind, and ice, and hailstorm, -there is always a possibility of the slender metal strips being -damaged, so as to interrupt their continuity, and thus destroy the -free passage of the electric force. Instances have happened in which -the damage done was so slight as to be scarcely visible, and still -sufficient to destroy the efficacy of the conductor. Nothing but the -regular testing by a galvanometer--one of which is described, with an -illustration, on page 60--by an experienced person can establish the -fact that the action of the conductor remains perfect. - -A second important cause for inspection lies in the necessity of always -ascertaining with accuracy whether the earth connection is really in a -faultless state. The immense significance of the earth connection--the -basis, in more than one sense, of lightning protection--having been -dwelt upon in the preceding chapter, it is only necessary here to -state that, even if perfectly secured at the outset, it is liable -to disarrangements. One not infrequent accident causing them is a -change in the soil from moisture to dryness, which may be brought -about either by altered drainage or long absence of rain. The dangers -which threaten a break in the earth connection by altered or improved -drainage are of the most serious kind, and likely to become more so -from year to year. Not only the soil of our towns and cities, but even -that of our villages, and the fields themselves, is getting ever more -honeycombed by drain-pipes, until almost every drop of moisture is -sucked out of the ground. No doubt the pipes themselves may improve the -earth connection, if of iron or any other metal. But very frequently -they are of earthenware, in which case they are far more dangerous -than useful, even if filled with water. To guard against the danger -likely to arise from changes in the drainage, it would be wise to have -a thorough examination, by means of the test galvanometer, of all -lightning conductors near to or affected by alterations in the drains, -whenever completed. The same recommendation may be made as regards -cases where the soil has become unusually dry after a long absence of -rain. Few persons, except those who have made a study of the subject, -can form an idea to what depth such dryness often extends, more -especially in sandy and gravelly soils. - -There is a third ground, as material for consideration as each of the -two preceding ones, upon which the regular inspection of lightning -conductors must be strongly urged. It is, that constant alterations -in the interior of buildings, private residences as well as public -edifices, may serve to destroy the efficacy of a conductor which was -originally good, even to perfection. Thus a roof may be repaired, and -lead or iron introduced where it was not before; or clamps of iron may -be inserted in the walls of houses, to give them greater strength; -or, in fact, any changes may be made which bring masses of metal more -or less in proximity to the conductor. Under such circumstances, the -efficacy of the conductor is destroyed just in proportion as the -metal forms a better path for the dispersion of the electric force -than the one artificially prepared. There are hundreds of instances -to prove that changes made in buildings, such as the addition of a -leaden roof without, or the iron balustrade of a staircase within, -diverted the current of the electric force from the conductor on its -way to the earth, originally well provided for. In one rather curious -case, which happened at Lyons not many years ago, even an alteration -of the fixtures of a house proved destructive to the efficacy of a -conductor, perfect at the outset, the latter fact being shown in -that it had previously received a stroke of lightning and brought it -harmlessly to earth. The case was that of a banker possessed of the -piece of furniture indispensable to his profession, namely, a large -iron safe. It stood at first near an inner wall, in the centre of the -house; but wishing to add to its strength in resisting the attack of -burglars, the banker had it embedded partly in another wall adjoining -that on the outside, near a place where the masonry was held together -by some large iron clamps. In delightful ignorance of the effect of -this removal of his safe inside the house upon the lightning conductor -outside--an ignorance which would have been the same, probably, among -999 persons out of 1,000--the banker sat quietly down to dinner with -his family one day in July, when a terrific shock made the whole house -tremble to its foundations, upsetting furniture and breaking glasses. -The idea of an earthquake naturally came up at once; but when looking -out of the window (shivered to pieces) the banker was told by a crowd -assembled outside that there had been no earthquake, but that his house -had simply been struck by lightning, as it had been before. But while -previously the electric force had passed silently into the ground, -unknown even to the inmates of the house, and its passage verified -only by the accidental observation of a neighbouring meteorologist, -it had this time left its appointed path, seeking a new road more -strongly attractive. The lightning had found its way into the banker’s -safe, filled with gold. Once inside, the electric current, not finding -a farther outlet, had expended its force in shattering the walls -and making the house tremble, besides melting some gold and burning -banknotes. The investigation of the case at the time made some noise, -but it had one most useful result--it led to the institution of a new -office in connection with the Department of Public Architecture of the -city of Lyons, that of an inspector of lightning conductors. He was -charged to examine at stated intervals, or as often as circumstances -seemed to require it, the conductors applied to all the public -buildings of the city, to ascertain their efficacy, and, if not deeming -them in good condition, to effect all necessary repairs. Shall we -repeat, again and again, ‘They manage things better in France’? - -The regular inspection of lightning conductors, as yet unknown or -all but unknown in England, has been for a long time in practice in -several States of Continental Europe, among them Germany and France. -The origin of such inspection may be traced to Northern Germany. It has -been mentioned before (Chap. IV., page 43) that the first lightning -conductor set up over a public building in Europe was erected on the -steeple of the Church of St. Jacob, Hamburg, and that the extension -of conductors in the city and neighbourhood was so rapid, that before -five years had gone by there were over seven hundred conductors. ‘To -this day they are comparatively more numerous in this district than -anywhere else in Europe.’ To this day, too, the scientific aspect of -the question of lightning protection, and the statistics connected with -it, are more appreciated here, and have been more closely investigated, -than in any other part of Europe. In recent years, this has been more -particularly the case in the territories to the north of the city of -Hamburg, the German province of Schleswig-Holstein. Not even in the -country of their origin, and the one which, as yet, has the greatest -number of them in use, have the ‘Franklin rods’ given rise to so much -serious study as in that part of Germany. - -Thunderstorms are more numerous, on the average, in Schleswig-Holstein -than in any other part of Central and Northern Europe--due, probably, -to the fact of the province not only being a narrow peninsula, with the -Baltic on the east, and the German Ocean on the west, but intersected -by rivers and canals, producing a generally moist atmosphere. Almost -all public edifices in the province, and the great majority of private -buildings above the rank of mere cottages, are protected by lightning -conductors; and to aid in their extension there are special laws under -which damages by lightning are not made good, except to a limited -extent, by fire insurance companies, unless it is proved that the -edifices struck had been provided previously with efficient conductors. -These laws gave rise to a curious investigation some three or four -years ago. It was found that the principal fire insurance office--an -institution under the patronage of the Government, called the -‘Landesbrandkasse,’ or ‘County Fire Insurance Office’--had been called -upon a number of times to pay for damage caused by lightning in cases -where the buildings were provided with lightning conductors of the best -kind, in apparently perfect condition. Though the cases were very few -indeed--namely, but four out of 552 claims for damages from lightning -which had been made in the course of eight years--still, the interest -taken in the subject was so great, that the managers of the institution -appointed a special commissioner to inquire thoroughly into the -matter as to how it could happen that buildings provided with proper -conductors could ever be struck by lightning. The gentleman chosen to -undertake this task was Dr. W. Holtz, of Greifswald, well known as -having given much time to the study of the phenomena of electricity, -as well as the construction of lightning conductors. Dr. Holtz in due -course made his report, which was afterwards published in a scientific -journal called ‘Nachrichten des Naturwissenschaftlichen Vereins für -Neuvorpommern und Rügen,’ being the organ of a society under the latter -title. The report--which must be completely unknown in this country--is -full of interest, and well deserves being extracted from in several -notable particulars. - -Dr. Holtz begins his report by referring to the well-known fact, -already dwelt upon, that in some instances lightning conductors have -got into disrepute because houses provided with them have been struck -and damaged. ‘Unhappily,’ he says, ‘there are still at the present -moment many persons who question the utility of conductors, simply -because it happens now and then, that lightning, apparently in entire -disregard of them, falls upon dwellings. These persons completely -overlook two facts, namely: first, that such cases are excessively -rare; and, secondly, what is far more important and more to the -point, that it is beyond dispute that whenever buildings nominally -provided with conductors are struck by lightning, these conductors are -not in an efficient state. Such buildings are absolutely in the same -condition as if they had no conductors at all.’ Dr. Holtz then goes on -to speak of his journey of inspection to inquire into the causes of -failure, or so-called failure, of lightning conductors. He says that, -having examined a vast number of conductors, he found that in a good -many instances real use had been sacrificed to ornament. He expresses -this somewhat quaintly, in scientific style, apparently with the -intention of not giving offence to anybody--not even to manufacturers -of lightning conductors. ‘It was found by me,’ Dr. Holtz states, -‘that the unreal was frequently placed above the real, and that many -lightning conductors, although very costly in the first instance, -afforded no certain protection.’ The meaning of this clearly is, that -too much attention is given to the upper part of conductors, especially -the pointed top--frequently covered with needless gilding--and far -too little to the part underground, forming the all-important earth -connection. It is a criticism true for other countries besides Germany. - -Among the many interesting remarks of Dr. Holtz, evidently based on a -thorough knowledge of the subject which he treats, are some good ones -about the necessity of constructing lightning conductors, not slavishly -after old models, but in conformity with modern requirements, carefully -considering the nature of the buildings to be protected and their -materials. ‘The increase of metals,’ he says, ‘in the construction -of houses, both inside and outwardly, is assuming larger proportions -from year to year. An absolute consequence of it is, that the electric -force called lightning is tempted, far more than was the case in older -dwellings, not to go to the conductor at all, or, if attracted to -it, to leave the path afterwards, seeking other attractions. I found -this to have been the case, in the course of my investigations, in -several instances, two of them notable ones. The first was that of the -public school of the town of Elmshorm, struck by lightning away from -the conductor; and the second that of the church of St. Lawrence, in -the town of Itzehoe, where the conductor was struck at first, but the -lightning deviated subsequently from its metal path. In both cases I -found that the non-efficacy of the conductor was caused by a number of -gas-pipes. But there are many other metallic masses besides gas-pipes -which interfere thus with the proper action of lightning conductors. -More or less, all metals do so, especially those which lead to the -ground, or are in contact with moisture. Water-pipes will attract -the electric force even more than gas-pipes, and likewise the metal -tubes which carry the rain from the roof into the ground. But it may -also happen that mere ornaments on the roof, more particularly if of -thick metal, and carried all along the top and sides, may divert the -electric force from the conductor, although they have no connection -whatever with the ground. Even the many wires outside and inside -houses, for bells and other purposes, may do mischief. There can be -no doubt whatever that the large increase of the use of metals in the -construction and ornamentation of modern houses has led to far greater -danger to which they are exposed from lightning. At the same time -there is equally little doubt that all this increased danger may be -absolutely guarded against by the setting up of lightning conductors -by competent persons, carefully designed to meet all cases.’ Dr. Holtz -adds, further on, that one most important element of protection to -be obtained from conductors consists in the regular testing of them, -without which, indeed, there can be no permanent security. - -What the writer says on the inspection of conductors is particularly -worth quoting. ‘A lightning conductor,’ he remarks, ‘however excellent -in the first instance, may lose all its good qualities, for several -reasons. In the first instance it may suffer, like all mundane things, -from age. The decrepitude will come on all the sooner whenever the -materials are not of the best kind, or whenever little care has been -taken in properly connecting the various parts. This is frequently -the case in conductors of old design. But, even if all has been done -that scientific skill can accomplish, age will make itself felt some -time or other. Oxidation will play its part; so will the warfare of -the elements. However safely secured at first, the attachment of the -parts to the buildings will get loose, or perhaps even broken. Repairs -consequently become indispensable. When are they to be effected? It -can only be indicated by testing the conductor from time to time.’ -Dr. Holtz next dwells at some length on the necessity of conductors -being designed by thoroughly competent persons; not mere ‘lightning -rod men,’ who are able to take into account all the particulars of the -building which is to be protected, more especially the metal employed -in the construction. ‘A conductor,’ he truly remarks, ‘cannot be -expected to be a trustworthy protection against the destructive force -of lightning, if simply set up over a house without consideration of -its outer and inner features. Perhaps in buildings of olden times, into -the construction of which metals seldom or never entered, a simple -wire running from top to bottom, surmounted by an iron rod, was quite -sufficient, but this is no longer the case, all the circumstances -having been completely altered. The wire, however thin, was not merely -the best, but the only path for the electric force. But at present -the masses of metal used in the construction of buildings constitute -a number of rival paths, and it requires very careful consideration -indeed to lay down an absolutely infallible lightning conductor in such -a way as to overcome all influences opposing its action. Therefore -conductors of old construction can not only not be expected to be -efficacious under modern exigencies, but even those made at the present -time cannot be expected to be efficient under circumstances which, -probably, the future may bring forth. There is really nothing else to -make a lightning conductor a safe protection under all circumstances, -and at all times, but regular, constant, and skilful examination.’ - -To the three great causes before indicated which make the regular -testing of conductors an almost imperative necessity, several minor -ones may be added. Among them may be cited the frequency of repairs -of the walls and roofs of houses. Our modern houses, as we all know, -are not built, like those of the Romans, ‘for an eternity,’ but in the -vast majority, particularly in towns, are ‘leaseholds for ninety-nine -years.’ Many of them, perhaps, can scarcely be expected to last -ninety-nine years, being constructed by their builders on the principle -of Peter Pindar’s razors, ‘not to shave, but to sell.’ Hence the -absolute necessity of repairs without end. Without casting the least -slur upon the character of the artisans who execute these, bricklayers, -plasterers, painters, plumbers, and others, it may be fairly asserted -that they are densely ignorant as to the nature of lightning -conductors. It is not at all a wonder that this should be so, since -they share their ignorance with many persons of far higher education, -who know no more of the action of the electric force in seeking its -way from the clouds into moist earth than they do of that of a voltaic -apparatus, or of a condensing steam-engine. These artisans, then, in -whose hands the repairs of houses are left, naturally treat the narrow -strip of metal running from the top of houses to the bottom with great -indifference, not having the slightest idea of its being one of the -most marvellous conceptions of the human mind. It has been reported, -on good authority, that there are frequently workmen to be found, such -as house painters and others, whose business it is to ‘decorate’ the -outside of dwellings with the stuff called ‘stucco,’ who feel a sort -of mild hatred for lightning conductors, as interfering with their -achievements, and, as they think, disfiguring the beauties which they -are creating. Woe to the poor conductor within their reach! Unless very -conspicuously placed, which is rarely the case, the tenant of a house -will seldom discover in time that the slender rope, or ribbon, which -gives him and his family protection against lightning has been broken -by cunning hands when the last repairs were effected, and the ends -stowed away in the gutter on the roof. The discovery will be made, in -the absence of inspection, probably, only under the fierce light of a -flash of lightning from a passing thunderstorm. - -If in towns the ever increasing accumulation of gas, of water, and of -drainage pipes constitutes a danger against the efficacy of lightning -conductors--to be guarded against only by frequent testing--there is -another source of danger arising in the country. It is in the planting -of new trees and the growth of old ones which is constantly going on -in the vicinity of the thousands of country houses and mansions with -which Great Britain is dotted from one end to the other, more than -any other country in the world. The fact has already been dwelt upon, -that trees are more liable to be struck by lightning than any other -natural objects, the reason of it being unknown, except in the very -probable surmise that the moisture in them forms the natural cause why -the electric force seeks its path through them to the earth. Whatever -the cause or causes, there can be no doubt that trees are incessantly -struck by lightning, and that they are the more exposed to be struck -the higher they are and the wider the extent of their branches. -Consequently, wherever trees are being planted, or growing up around -houses, the greatest care should be taken in designing lightning -conductors, so as to provide against the action exercised by them in -juxtaposition to the electric force. Thus, if trees, originally small, -should reach to such a height above dwellings as to make it possible -that a stroke of lightning will fall upon them, in preference to the -conductor, the arrangements for protection will have to be altered, -so as to ensure the safety of the house nearest these particular -trees. Again, if, as often happens, there are new trees planted near -a building the side of which has no protection whatever, such as a -greenhouse or conservatory, the conductor should be extended in this -direction. In connection with trees, mention must be made of wells -and fountains, as possible dangers to the proper action of lightning -conductors. Many a disaster has been caused by newly-made wells to -dwellings which were previously well protected by conductors. The -only safeguard against danger arising from these and numerous other -causes, which it would be tedious to specify, lies in careful, constant -inspection and testing of conductors. - -It is lamentable to think that while the regular inspection of -lightning conductors has been admitted long ago to be a necessity in -many countries on the Continent of Europe, we as yet have taken no -steps whatever to realise it. There is, probably, not a single public -building in England which has conductors systematically tested from -time to time. While there are tens of thousands of edifices, private -and public, that are entirely without protection against lightning, -there are many thousands of others which, nominally protected, are -in reality in the same position. They have conductors, but it is -impossible to say whether they would be efficacious were a more than -usually heavy stroke of lightning to fall upon them. The inmates of -such dwellings live in fancied security, which is the more to be -deplored, as it would be so easy to make it real. All that is required -is a knowledge of the subject. With the growth of such knowledge it is -certain that the inspection of conductors will become general, with -the good effect, above all others, of setting at rest all doubts as -to the infallible security they afford, if properly constructed and -maintained, against damage from lightning. - - - - -APPENDIX. - -_BIBLIOGRAPHY OF WORKS BEARING UPON LIGHTNING CONDUCTORS._ - - - 1663. HIER. CARDANI de Fulgure liber unus. 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Der Rathgeber, wie man sich vor Gewittern - in unbewaffneten Gebäuden verwahren soll. 8vo. Mannheim. - - BODDE. Grundzüge zur Theorie der Blitzableiter. 8vo. Münster. - - 1810. J. PH. OSTERTAG. Antiquarische Abhandl. über - Gewitterelektricität. Auswahl aus den kl. Schriften - des.... Sammlung ii. 455. Salzbach. - - J. A. H. REIMARUS. Ueber die Sicherung durch Blitzableiter. - Gilbert’s Ann. xxxvi. 113. - - 1811. L. VON UNTERBERGER. Nützliche Begriffe von den - Wirkungen der Elektricität und der Gewittermaterie, - nebst einer practischen Belehrung 8vo. Wien. - - M. V. IMHOF. Ueber das Schiessen gegen heranziehende - Donner- und Hagelgewitter. 4to. München. - - B. COOK. On the Prevention of Damage by Lightning. - Nicholson’s Journal of Philosophy and Chemistry. Aug. - 1811, and Feb. 1812. - - 1812. J. K. GÜTLE. Neue Erfahrungen über die beste Art - Blitzableiter anzulegen. 8vo. Nürnberg. - - 1814. G. J. SINGER. Elements of Electricity and - Electro-Chemistry. 8vo. 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Französ. Mit einer Abbildung. 8vo. - Weimar. - - GAY-LUSSAC’S Bericht über La Postolle’s Blitzableiter aus Stroh. - Gilb. Ann. lxviii. 216. - - MÜLLER und HOFMANN. Einige prüfende Versuche hierüber. - Gilbert’s Annalen, lxviii. 218. - - LINDNER. Blitzableiter von Strohseilen. Magazin der neuesten - Erfindungen, Entdeckungen und Verbesserungen von - Poppe, Kühn und Baumgärtner. Neue Folge, ii. 18. - - VINCENT. Blitzableiter von Stroh. Journ. d. Connaiss. Usuell. et - Pratiques, et Recueil des Notions etc., par Gillet de - Grandmont et C. de Lasteyrie et d’autres. 8vo. xix. - 281. Paris. - - 1822. DAVY. Neue tragbare Blitzableiter. Polyt. Journ. ix. - 133. - - WEBER. Die Sicherung unserer Gebäude durch - Blitzstrahlableiter, theor. und pract. beleuchtet und - bewährt, sammt einer Beurtheilung der Ableiter aus - Stroh. Landshut. - - 1823. HARRIS. 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Instruction adoptée par la Commission qui - a été chargée d’étudier la meilleure disposition à - donner aux Paratonnerres surmontant les Edifices - municipaux et departementaux. Comp. Rend. lxxxi. 1118. - - E. SAINT-EDME. Sur la Construction des Paratonnerres. Ib. - 949. - - J. CHEMINEAU. Une Description et un Dessin de - Perfectionnement apportés aux Paratonnerres. Ib. 1203. - - M. FIZEAU. Avis de la Commission des Paratonnerres sur une - Disposition nouvelle proposée pour les Magasins à - Poudre. Ib. lxxx. 1440. - - LT. COLONEL STOTHERD, R.E. On Earth Connections of - Lightning Conductors. Jour. Soc. Tel. Eng. iv. 262. - - J. CLERK MAXWELL. Lightning Conductors. Ib. 429. - - DR. ANTONIN DE BEAUFORT. Notice sur les Paratonnerres. 8vo. - Chateauroux. - - J. F. SPRAGUE. Electricity: its Theory, Sources, and - Applications. 8vo. London. - - DR. MANN. Lightning Conductors. Jour. Soc. of Arts. xxiii. - 528. - - R. F. MICHEL. On the Construction and Maintenance of - Lightning Conductors. 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Des Paratonnerres à pointes, à conducteurs et - à raccordements terrestres multiples. 8vo. Bruxelles. - - 1878. M. MELSENS. Cinquième Note sur les Paratonnerres. - Bulletins de l’Acad. Royale de Belgique, xlvi. No. 7. - - W. HOLTZ. Ueber die Theorie, die Anlage und die Prüfung - der Blitzableiter. 8vo. Greifswald. - - E. CARTAILHAC. Superstitions about Thunderstorms. L’Age de - Pierre dans les Souvenirs et Superstitions populaires. - 8vo. Paris. - - R. J. MANN. Further Remarks concerning the Lightning Rod. - Jour. Soc. Arts, xxvi. 328. - - M. MASCARL. On Artificial Thunderstorms. Nature, xvii. 515. - - R. P. BROWN. Effects of a Thunderstorm on the Colon - Lighthouse. Jour. Soc. Tel. Eng. vi. 330. - - PROF. C. V. ZENGER. On the Law and Origin of Thunderstorms, - from the Bulletin International, Paris. Nature, xvii. - 362. - - RICHARD ANDERSON. On Lightning Conductors and Accidents by - Lightning. The Electrician, vol. i. 215. - - DR. NIPPOLDT. Dimensions of Lightning Rods. Telegraphic - Journal, vi. 78. - - J. B. JOULE. On a Remarkable Flash of Lightning. Nature, - xviii. 260. - - 1879. S. A. R. On the Cause of Thunder. Nature, xx. 29. - - R. S. NEWALL. On the Importance of a Sufficient Earth Contact - for Lightning Conductors. Times, May 30 and June 14. - - Curious Effects of Lightning. Electrician, vol. iii. 181. - - AYRTON and PERRY. On the Earth Connection of Lightning - Conductors. Nature, xix. 475. - - G. W. CAMPHUIS. On the Effects of Lightning. Nature, xx. 96. - - R. S. NEWALL. On Lightning Conductors. Nature, xx. 145. - - CHARLES S. TOMES. On Lightning Conductors. Nature, xx. 145. - - - - -INDEX. - - - A - PAGE - Accidents and fatalities from lightning 169–197 - - Admont, Styria, convent struck by lightning 67 - - Air-pump, the inventor of the 2 - - Alatri, the Cathedral of, struck by lightning 203 - ———— Father Secchi’s account thereof 203 - - Allamand (John Nicholas), his researches on electricity 4 - - Amber or ‘Electron’ and its properties 1 - - America, lightning protection in 133 - ———— the tramping ‘Lightning-rodmen’ of 133 - ———— account of the details of the American system 134 - ———— utilisation of gutters and rain-pipes in 134 - ———— the protection of chimneys and air-shafts in 136 - ———— the method of constructing the earth-terminal in 136 - ———— the protection of mineral oil tanks 138 - - Antrasme, France, church twice struck by lightning at the same - point 65 - ———— Arago’s remarks thereof 66 - - Arago on the observation of thunderstorms 62 - ———— on the efficiency of lightning-conductors 73 - ———— on whether lightning-conductors should be carried down - inside or outside a building 159 - - Area of protection theory 77, 101, 126, 145 - - Auffangstange, the German 145 - - Austria, statistics of fires caused by lightning in 174 - - - B - - Baden, statistics of deaths from lightning in 173 - - ‘Balls _v._ points,’ the controversy of 40 - - Banker’s iron safe struck by lightning 221 - - Bavaria, statistics of fires caused by lightning in 173 - - Becquerel (Antoine C.), his experiments on the conductivity of - metals 51 - - Bevis (Dr.), experiments in electricity 7 - - Bibliography of works bearing upon lightning-conductors 231 - - Black Rock, Cork, St. Michael’s Church struck by lightning 184 - - Brass wire, the use of, for lightning-conductors 105, 107 - - Brescia, Italy, powder-magazine destroyed by lightning 200 - - Brussels, the Hôtel de Ville. The system of lightning-conductors - at 111 - - Buffon (Count de), his opinion of Franklin’s first pamphlet on - electricity 19 - - Buffon (Count de), his promotion of experiments in electricity 20 - - Buttor (Eustace) account of the striking of Christ Church, - Clevedon, by lightning 208 - - - C - - Carthusian monks at Paris, electrical experiments made on 6 - - Cavendish (Lord Charles), experiments in electricity 7 - - Chains, iron, the use of, for lightning-conductors 102 - - Chimney-shafts, the protection of, from lightning 163 - - Chimneys and air-shafts, the protection of, from lightning in - America 136 - - Churches struck by lightning 27, 38, 64, 65, 146, 147, 153, 176, - 177, 181, 182, 183, 184, _see also_ 186–196, 201, 203, 208 - - Churches, the protection of, from lightning 152, 156 - - Coiffier first draws lightning from the atmosphere 21 - - Cleopatra’s Needle, the protection of, from lightning 141 - - Clevedon, Christ Church struck by lightning 208 - ———— Eustace Buttor’s account thereof 208 - - Cockburn (Sir George) and Sir William Snow Harris 89 - - Collinson (Peter) Correspondence with Benjamin Franklin 12, 13, 17 - - Compass reversed by a lightning-stroke 56 - - Compensator for contraction and expansion in lightning-conductors 128 - - Copper, the relative value of different kinds of 109 - ———— the necessity for its purity when used for - lightning-conductors 109 - ———— and iron, the relative electrical conductivity of 52, 143 - ———— rope-conductors, the proper thickness and weight for - different buildings 151 - ———— description of 62, 164 - - Cromer, Norfolk, church damaged by lightning 147 - - Cuneus, his experiments in electricity 4 - - Cyprus, the copper of 52 - - - D - - Dalibard (M.), his experiments in electricity 20 - - Davy (Sir Humphrey), his experiments on the conductivity of metals 50 - - Deaths from lightning, statistics of 170–175 - - De la Rive (Professor) on the origin of atmospheric electricity 71 - - Dumdum, India, destruction of a magazine by lightning at 92 - - - E - - Earth connection, the French methods of arranging the 131 - ———— general description of 198–217 - ———— Benjamin Franklin on 199 - ———— Rev. Dr. Hemmer on 200 - ———— Professor Landriani on 201 - - Electrical machines, Otto von Guericke’s 2 - ———— Sir Isaac Newton’s 2 - - ‘Electrical tubes,’ the mania for 9, 10 - - Electricity, the early history of 1 - ———— the discovery of the instantaneity of its movement 8 - ———— positive and negative, Benjamin Franklin on 26 - - ‘Electron’ or amber, and its properties 1 - - Electro-magnetism, Hans Oersted’s researches in 57 - - England and Wales, deaths from lightning in 170 - - England, lightning protection in 140–168 - - - F - - Fatalities and accidents from lightning 169–197 - - Fires caused by lightning in Russia 171 - - Folkes (Martin), experiments in electricity 7 - - France, the ‘Instruction’ of the Paris Academy on - lightning-conductors 75 - ———— the general adoption of lightning-conductors in 77 - ———— the protection of powder-magazines in, from lightning 82 - ———— lightning protection in 125 - ———— neglect of lightning-conductors in 125 - ———— account of the details of the French system 126 - ———— the ‘area of protection’ theory in 126 - ———— the ‘ridge-circuit’ as used in 129 - ———— deaths from lightning in 171 - - Franklin (Benjamin), his early life 10, 11 - ———— his first experiments in electricity 12–19 - ———— correspondence thereon with Peter Collinson 12, 13, 17 - ———— on the identity of lightning and electricity 16 - ———— ‘New Experiments and Observations in Electricity’ 18 - ———— his ‘kite’ experiment 22 - ———— honours conferred on him 24 - ———— his first lightning-conductor 25 - ———— his experiments therewith 25 - ———— on positive and negative electricity 26 - ———— his lightning-conductor on West’s house 30 - ———— his letter to Professor Winthrop defending - lightning-conductors 36 - ———— his troubles in making his first lightning-conductor 101 - ———— on the earth connection of lightning-conductors 199 - - French technical terms for lightning-conductors 102 - - Fuller (Thomas) on fires caused by lightning 176 - - - G - - Galvani’s experiments on animal electricity 70 - - Galvanometer, the invention of the 58 - ———— a new form of 60 - - Geneva, the progress of lightning-conductors in 43 - - Genoa, St. Mary’s Church struck by lightning 201 - ———— Professor Landriani thereon 202 - - ‘Gentleman’s Magazine’ _quoted_ 40 - - George III., his opinions on lightning-conductors 41, 42 - - German technical terms for lightning-conductors 102 - ———— theories on the earth connection 212, 214 - - Germany, the progress of lightning-conductors in 43 - - Gilbert (Dr. William), his electrical discoveries 2 - - Gratz, Austria, buildings struck by lightning at 68 - - Gray (Stephen), his researches on electricity 3 - - Guericke (Otto von) his electrical machine 2 - - - H - - Harris (Sir William Snow) his efforts for the protection of ships - from the effects of lightning 85 - ———— and Sir George Cockburn 89 - ———— his system for protecting ships 90 - ———— his ‘Instructions for powder-magazines’ 93 - ———— his system for the protection of Westminster Palace 98, 118 - - Hauksbee (Francis), his researches on electricity 2 - - Height of lightning-clouds 67 - - Hemmer (Rev. Dr.), his theories on the earth connection 200 - - Henly’s system for protecting ships from lightning 90 - - ‘Heretical-rods’ 44 - - Highbury Barn, electrical experiments made at 8 - - Holtz (Dr. W.), on the construction and maintenance of - lightning-conductors 223 - - Humboldt (Alex. von) on the height of lightning-clouds 67 - - - I - - India, the use of lightning-conductors in 92 - - Ingenhousz (Dr. Johan) and lightning-conductors 47 - - Inspection of lightning-conductors 218–229 - - ‘Instruction’ of the Paris Academy on lightning-conductors 75 - - Insulators, the dangers of 147, 160, 176 - - Iron and Copper, the relative electrical conductivity of 52, 143 - ———— safe, a banker’s, struck by lightning 221 - - Italy, the progress of lightning-conductors in 44 - - - J - - Jarriant’s system of lightning-protection 133 - - Josephus’ account of Solomon’s Temple 63 - - - K - - Kant (Immanuel) on Benjamin Franklin 24 - - Kastner (Professor), his report on the partial destruction of - Rosstall Church by lightning 106 - - Kew, lightning-conductor erected by George III. at 41 - - Kinnersley (Ebenezer), his lectures on lightning-conductors 27 - - Kite, Benjamin Franklin’s experiment with 22 - - Kleist (Ewald George von) and the discovery of the Leyden Jar 5 - - - L - - Landriani (Professor), his theories of earth protection 201 - - Laughton-en-le-Morthen, church damaged by lightning 153, 176 - ———— R. S. Newall’s comments thereon 153, 154 - - Lead, the use of, for lightning-conductors 104 - - Leicester, St. George’s Church struck by lightning 177 - - Lenz (Professor) his experiments on the conductivity of metals 52 - - Leopold, Duke of Tuscany, and lightning-conductors 44 - - Le Roy (David) and the protection of the Louvre from lightning 80 - ———— (J. B.), his theory of protecting buildings from lightning 101 - - Leyden Jar, the first discovery of the 5 - - Lightning, superstitions in regard to 63 - - Lightning-clouds, the height of 67 - - Lightning-conductors, the discovery of 17–24 - ———— early experiments with 25, 33 - ———— the clergy on 26 - ———— Professor Winthrop’s defence of 26, 27 - ———— E. Kinnersley’s lectures on 27 - ———— ‘Poor Richard’s Almanac’ on 28 - ———— the gradual spread of 34–48 - ———— Abbé Nollet’s animadversions on 35, 37 - ———— Franklin’s reply thereto 36, 37 - ———— their general use in North America 38 - ———— their first erection on St. Paul’s 39 - ———— their progress in Germany 43 - ———— Italy 44 - ———— the various metals used for 50 - ———— Arago on the efficiency of 73 - ———— the French ‘Instruction’ on 75 - ———— Professor Pouillet on 78 - ———— for ships 85 - ———— Sir William Watson’s system of, for ships 87 - ———— Sir William Snow Harris’s system of, for ships 90 - ———— F. McTaggart’s opinion of 92 - ———— their use in India 92 - ———— the best material for 100–110 - ———— German and French technical terms for 102 - ———— and weathercocks 121 - ———— Jarriant’s form of 133 - ———— the twofold function of 142 - ———— the insulation of 147, 160, 176 - ———— Newall’s system of 140–168 - ———— should they be carried down inside or outside the building 158 - ———— Professor Clerk Maxwell’s theory of 164 - ———— the necessity for periodically inspecting 218 - ———— Dr. W. Holtz on the construction and maintenance of 223 - - ‘Lightning-rod men,’ the tramping, of America 133 - - Lightning and thunderstorms, character of 62 - ———— protection, inquiries into 73–84 - - Line of least resistance, the 142, 148 - - Lisle (M. de) on the height of lightning-clouds 67 - - Louis XV. and experiments in electricity 6, 19 - - Louvre, the protection of the, from lightning 80 - ———— the first public building in France fitted with - lightning-conductors 80 - - - M - - McTaggart (F.), his opinion of lightning-conductors 92 - - Magnetisation of metals by lightning 56 - - Magnetism and lightning, the connection between 56 - - Majendie (Major), report on the destruction by lightning of the - powder magazine, Victoria Colliery, Burntcliffe 147 - - Marly-la-Ville, Dalibard’s electrical experiments at 20 - - Matthiessen (Professor), his researches on the conductivity of - copper 109 - - Maxwell (Professor Clerk, F.R.S.), his theory of lightning - protection 164 - - Melsens (Professor), his system of lightning-conductors at the - Hotel de Ville, Brussels 111 - - Merton College Chapel, Oxford, struck by lightning 182 - - Metals as conductors of electricity 49–61 - - Metals, the different conductivity of various 50–55 - - Michel (R. F.), his modified terminal-rod 132 - - Mineral oil-tanks, the protection of, from lightning in America 138 - - Monks, Carthusian, electrical experiments made on 6 - - Musschenbroek (Peter Van), his researches on electricity 4, 5 - - - N - - Newall (R. S., F.R.S.), his copper-rope manufactory 110, 142 - ———— on the church at Laughton-en-le-Morthen being struck by - lightning 153, 154 - - Newall’s system of protecting buildings from lightning 140 - ———— copper-rope conductors 162, 164 - - Newbury Church, Massachusetts, struck by lightning 27 - - New River, electrical experiments made on the 8 - - Newton (Sir Isaac), his electrical machine 2 - - Nollet (Abbé), his criticisms on Franklin’s electrical - experiments 19, 35 - ———— his animadversions on lightning-conductors 35, 37 - ———— Franklin’s reply thereto 36, 37 - - - O - - Oersted (Hans Christian) his researches in electro-magnetism 55, 57 - - Ohm (Professor), his experiments on the conductivity of metals 53 - - Ohm’s law 59 - - Oil, mineral, tanks, the protection of, from lightning in America 138 - - Orsini family and lightning-conductors 64 - - Oxford, Merton College Chapel struck by lightning 182 - - - P - - Padua, the first lightning-conductor in 48 - - Painting lightning-conductors 129 - - Paratonnerres, the Paris Academy ‘Instruction’ on 75 - - Paris Academy, the ‘Instruction’ of the, on lightning-conductors 75 - - Paris, death of two persons by the fall of a ‘tige’ from steeple - of St. Gervais 146 - - Peltier (Jean Athanase), his researches in electricity 71 - - ‘Physico-mechanical experiments,’ Hauksbee’s 3 - - Pliny the Elder, on the observation of thunderstorms 62 - - ‘Points _v._ balls,’ the controversy of 40 - - ‘Poor Richard’s Almanac’ and lightning-conductors 28 - - Pope, the, on electrical experiments on monks 7 - - Pouillet (Professor Claude), his experiment on the conductivity of - metals 54 - ———— on lightning-conductors 78 - - Powder-magazines in France, the protection of, from lightning 82 - ———— Sir William Snow Harris’s instruction for protecting 93 - - Pringle (Sir John) his resignation of the Presidency of the Royal - Society in 1777 41 - - Protestantism and lightning-conductors 43 - - Prussia, statistics of deaths from lightning in 170 - - Purfleet, building struck by lightning in 1777 41 - - - R - - Rarefied air, the conductivity of 142, 149 - - Raven (Mr.), his house in Carolina, U.S., struck by lightning 159 - ———— Arago’s comments thereon 159 - - Réaumur (Rene Antoine de) Musschenbroek’s letter to, on the Leyden - Jar 5 - - ‘Return strokes’ of lightning 70 - - Richmann (Professor G. W.), his experiments on electricity 31 - ———— his death thereby 32 - - ‘Ridge Circuit’ as used in France 129 - - Robespierre and lightning-conductors 36, 43 - - Roman Catholicism and lightning-conductors 42, 44 - - Rosenburg, Austria, church repeatedly struck by lightning at 64 - - Rosstall, Bavaria, church struck by lightning at 105 - ———— Professor Kastner’s report thereon 106 - - Royal Navy, vessels of the, destroyed by lightning 88 - - Royal Society and Benjamin Franklin 17 - - Russia, statistics of deaths from lightning in 171 - - - S - - St. Bride’s Church, London, struck by lightning in 1764 38 - ———— Dr. William Watson’s account thereof 39 - ———— account of the damage done 183 - - St. Omer, the first lightning-conductor at 35 - - St. Paul’s Cathedral, the erection of lightning-conductors upon 39–41 - - Saussure (Professor Horace de) erects the first lightning-conductor - in Geneva 43 - ———— the opposition thereto and his manifesto thereon 43, 44 - ———— on the height of lightning-clouds 67 - ———— on the origin of atmospheric electricity 70 - - Schleswig-Holstein, thunderstorms in 222 - - Secchi (Father) on the protection of churches from lightning 203 - - Ships destroyed by lightning, statistics of 88 - - Shooter’s Hill, electrical experiments made at 8 - - Siena, the erection of lightning-conductors on the Cathedral at 45 - - Smoke, the conductivity of 142 - - Solokow and Professor Richmann’s experiment in electricity 32 - - Solomon’s Temple, its immunity from lightning-strokes 63 - - Staples for lightning-conductors 163 - - Statistics of deaths, fires, and damage caused by lightning 170 - - Superstitions in regard to lightning 63 - - Sweden, statistics of deaths from lightning in 172 - - Switzerland, statistics of deaths caused by lightning in 175 - - - T - - Terminal-rods, Newall’s 144 - - Thomson (Sir William, F.R.S.), his researches on the conductivity - of copper 109 - - Thunderstorms and lightning, the character of 62 - - ‘Tightening-screw,’ the 162 - - Tin, the use of, for lightning-conductors 104 - - Toaldo (Abbé Giuseppe) and lightning-conductors 45 - - ‘Tomlinson’s Thunderstorm,’ _quoted_ 177 - - Torpedo fish and electric shocks 1 - - Trees, their liability to be struck by lightning 228 - - Tuscany, the erection of lightning-conductors upon - powder-magazines in 48 - - - U - - United States, lightning protection in 133 - - Units, the law of 68 - - - V - - Vaccination and lightning-conductors, analogy between the progress - of 46 - - Venice, the erection of lightning-conductors in 48 - - Victoria Colliery, Burntcliffe, destruction of the magazine by - lightning 146 - ———— Major Majendie’s report thereon 147 - - Volta and the ‘return stroke’ 70 - - Voltaire, his _bon mot_ concerning lightning 158 - - - W - - Wall (Dr.), on electricity and lightning 3 - - Watson (Dr. William), experiments in electricity 7 - ———— the first to erect a lightning-conductor in England 38 - ———— on St. Bride’s Church being struck by lightning 39 - ———— and the protection of the Royal Navy from lightning 86 - - Weathercocks and lightning-conductors 21 - - Weber (Dr.) and the law of units 59 - - West-End Church, Southampton, struck by lightning 181 - - Westminster Bridge, electrical experiments made from 7 - ———— Palace, the system of lightning-conductors at 98, 118 - - Wilson, the advocate of ‘balls _versus_ points’ 40 - - Winckler (Dr.), his experiments in electricity 5, 6 - - Windsor Castle inadequately provided with lightning-conductors 175 - - Winthrop (Professor), his defence of lightning-conductors 26, 27 - ———— Franklin’s letter to, defending lightning-conductors 36 - - Wurtemberg, statistics of deaths caused by lightning in 175 - - - Y - - Yelin (J. C. von) his advocacy of brass wire for - lightning-conductors 105 - - -_Spottiswoode & Co., Printers, New-Street Square, London._ - - - - -Transcriber’s Notes - - -Punctuation, hyphenation, and spelling were made consistent when a -predominant preference was found in this book; otherwise they were not -changed. - -Simple typographical errors were corrected; occasional unbalanced -quotation marks retained. The spelling of non-English words was not -checked or corrected. - -Ambiguous hyphens at the ends of lines were retained. - -In the original text, Figures and Footnotes were numbered from “1” in -each chapter. 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