Page:Popular Science Monthly Volume 25.djvu/695

Rh with small," the light and sound called forth when glass rods were rubbed were of the same nature as lightning and thunder. Franklin, from the time when the electrical experiments came under his notice, enthusiastically adopted this view. In a letter written to a friend in 1749, he very clearly expressed his reasons for this belief. In this communication he insisted upon the facts that the electric spark gives light like lightning; that the luminous discharge follows a similar crooked track; that this discharge is swift in its motion, is conducted by metals, is accompanied by an explosion when it escapes, rends bodies that it passes through, destroys animal life, melts metals, sets fire to inflammable substances, and causes a smell of sulphur—all of which attributes seemed to him to point to the identity of the phenomena. He also observed that the electric discharge was attracted by points, and stated that he was bent upon ascertaining whether lightning had not the same tendency. In the autumn of the following year he wrote to Mr. Collinson to say that he had satisfied himself in this particular; that he was entirely convinced of the identity of the so called electricity with lightning; that he believed the damage done by lightning descending from the clouds to the earth might be altogether prevented by placing iron rods, with sharp points, upon the summits of buildings; that he intended to test experimentally the soundness of his belief in that matter; and that he hoped other persons would assist him in his labors by following his example. This was virtually the definite forecast of the conductor which Franklin attached to his house in 1752.

In the mean time the suggestion that buildings might be protected from lightning by the use of iron rods with sharp points was incidentally communicated by Mr. Collinson to the editor of the "Gentleman's Magazine" in London, who, at once perceiving the practical importance of the hint, offered to print an account of Franklin's views in the form of a pamphlet. This offer was accepted, and, in the month of May, 1751, a pamphlet was published in London, entitled "New Experiments and Observations on Electricity made at Philadelphia, in America, by Benjamin Franklin." The pamphlet was not very warmly received in England, but it was enthusiastically welcomed and appreciated in France. Count de Buffon had it translated into French, and the translation appeared in Paris within four months of the publication of the original pamphlet in England. It was soon afterward translated into German, Italian, and Latin. The attention of scientific men in Paris was quickly drawn to the method of defense proposed by Franklin, and M. Dalibard, a man of some wealth, undertook to erect the apparatus at his country residence at Marly-la-Ville, some eighteen miles from Paris. The situation of the house was considered to be eminently favorable for the purpose, as the building stood some four hundred feet above the sea. A lofty wooden scaffold, supporting an iron rod an inch in diameter and eighty feet long, was erected in the