Читать книгу Lightning Conductors - F.C.S. Richard Anderson - Страница 6

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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.