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.