Benjamin Franklin; Self-Revealed, Volume 2 (of 2) / A Biographical and Critical Study Based Mainly on his own Writings

by Wiliam Cabell Bruce

It concludes with a lively paragraph:

Chagrined a little that we have been hitherto able to produce nothing in this way of use to mankind; 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, somewhat humorously, in a party of pleasure on the banks of Skuylkil. Spirits, at the same time, 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. 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 drank in electrified bumpers, under the discharge of guns from the electrical battery.

An electrified bumper, a note to the letter explained, was a small thin glass tumbler, nearly filled with wine, and charged, which, when brought to the lips of a person, gave him a shock, if he was close-shaved, and did not breathe on the liquor. Another note states that the biggest animal that the experimenters had yet killed was a hen.

A later letter to Collinson on the phenomena of thunder-gusts takes Franklin away from the Leyden Jar of the laboratory to the stupendous batteries of the outer universe—from the point of a bodkin to the lofty natural or artificial objects, upon which lightning descends from the illimitable sky. "As electrified clouds pass over a country," he remarks, "high hills and high trees, lofty towers, spires, masts of ships, chimneys, &c., as so many prominencies and points, draw the electrical fire, and the whole cloud discharges there." From this observation to the lightning rod was but a short step.

Another letter to Collinson in the succeeding year brings us to the lightning rod in principle if not in name. Speaking of what a sea captain had said of luminous objects, which had settled on the spintles at the topmast heads of his ship before an electrical shock, and burned like very large torches, he says:

According to my opinion, the electrical fire was then drawing off, as by points, from the cloud; the largeness of the flame betokening the great quantity of electricity in the cloud: and had there been a good wire communication from the spintle heads to the sea, that could have conducted more freely than tarred ropes, or masts of turpentine wood, I imagine there would either have been no stroke; or, if a stroke, the wire would have conducted it all into the sea without damage to the ship.

In the same letter, there is an adumbration of his grandest experiment, when he speaks of the flash from two of his jars as "our mimic lightning."

This letter also shows that with electricity Franklin had frequently imparted polarity to needles and reversed it at pleasure. Wilson, at London, he said, had failed to produce these results because he had tried it on too large masses and with too small force. The letter also evidences the fact that he had employed the electric spark for the practical purpose of firing gunpowder.

Another letter to Collinson dated July 29, 1750, is accompanied by an additional paper on the properties and effects of the Electrical Matter. It acknowledges the debt that Franklin owed to Collinson for the glass tube and the instructions which attended it, and to the Proprietary for the generous present of a complete electrical apparatus which "that bountiful benefactor to our library," as he calls him, had made to it. The telegraph, the Marconi tower, the telephone, the electric bulb, the electric automobile and the trolley car rise up before us when we read this observation in the paper that accompanied the letter: "The beneficial uses of this electric fluid in the creation, we are not yet well acquainted with, though doubtless such there are, and those very considerable." The paper is the most important that Franklin ever wrote on electricity; containing as it does the two suggestions which, when carried into execution, made his name famous throughout the world, that is to say, his suggestion, already quoted by us at length, that houses, churches and ships might be protected by upright rods of iron, and his suggestion, already quoted by us, too, as to how the identity of lightning and electricity could be established. The point of the bodkin and the electrified shot and ball, and the mimic brightness, agility and fury of the lurking fire in the wonderful bottle had led, step by step, to two of the most splendid conceptions in the early history of electrical science.[54]

With the discovery that electricity and lightning were the same thing, the real achievements of Franklin in the province of electricity came to an end. But he still continued his electrical experiments with undiminished ardor. We find him on one occasion prostrating with a single shock six persons who were so obliging as to lend themselves to the pursuit of scientific truth. Twice he was the victim of his own inadvertence. Speaking of one of these occasions, in a letter to a friend in Boston, he said: