Franklin's Electric Kite Experiment: Did Benjamin Franklin Really Fly a Kite to Prove That Lightning and Static Electricity Were One and the Same or Was It All Just a Hoax?

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AS A YOUTH, I LEARNED THAT BENJAMIN Franklin (1706-1790) flew a kite in a thunderstorm and drew lightning from the sky. I doubt that I ever knew why he did it, but I thought even then that he must have been crazy to do such a dangerous stunt. My concerns were for naught because, for one thing, he did not draw a lightning bolt down his kite string. Nor, according to Tom Tucker (1), did he ever construct or fly such a kite. Whoa Nelly! Heresy! Didn't Franklin state in writing that he flew an electric kite?

In his book Bolt of Fate: Benjamin Franklin and His Electric Kite Hoax (1), Tom Tucker believes that Franklin only intimated that he did the kite experiment as a hoax to get even with a certain member of the Royal Society of London who not only ignored some of his letters, but ridiculed some of his ideas at meetings of the Society, and plagiarized others. My dictionary defines a hoax as "An act intended to deceive or trick, either as a practical joke or a serious fraud." In his review of Tucker's book, Jessie Thorpe (2) claims that, if you follow Tucker's reasoning, it is difficult to conclude that Franklin did not perpetrate fraud. If not fraud, this leaves Franklin's hoax, if one has been committed, as a practical joke. Did Franklin have a reputation as a jokester? You bet he did, at least in the parts of his life outside of science! (3,4)

The Kite Experiment

In June 1752, Franklin proposed to place an electrical conductor as close to the clouds as possible to draw electricity from the same source where lightning seems to originate. He proposed to use a kite for this purpose. If he could draw a spark from a key at the base of the string with his hand, or charge a Leyden jar (an early type of condenser for storing an electrical charge) by touching the key to it, then he thought he would have proved that lightning and static electricity were identical, differing only in the magnitude of the discharge.

An article by Franklin appeared in The Pennsylvania Gazette on October 19, 1752, intimating that he had flown an electric kite. He sent a copy to his friend Peter Collinson (a member of the Royal Society of London) who relayed it to the Royal Society, where it was published in its Philosophical Transactions about a year later. Here it is:

As frequent mention is made in the public papers from Europe of the success of the Philadelphia experiment for drawing the electric fire from clouds by means of pointed rods of iron erected on high buildings, &c., it may be agreeable to the curious to be informed, that the same experiment has succeeded in Philadelphia, tho' made in a different and more easy manner, which anyone may try, as follows:

Make a small cross, of two light strips of cedar; the arms so long, as to reach to the four corners of a large thin silk handkerchief, when extended: tie the corners of the handkerchief to the extremities of the cross; so you have a body of a kite; which being properly accommodated with a tail, loop, and string, will rise in the air like those made of paper; but this, being of silk, is fitter to bear the wet and wind of thunder-gust without tearing.

To the top of the upright stick of the cross is to be fixed a very sharp-pointed wire, rising a foot or more above the wood.

To the end of the twine, next [to] the hand, is to be tied a silk riband [ribbon]; and where the twine and silk join, a key may be fasten'd.

The kite is to be raised, when a thunder-gust appears to be coming on, (which is very frequent in this country) and the person who holds the string, must stand within a door, or window, or under some cover, so that the silk riband may not be wet; and care must be taken, that the twine does not touch the frame of the door or window.

As soon as any of the thunder-clouds come over the kite, the pointed wire will draw the electric fire from them; and the kite, with all the twine, will be electrified; and the loose filaments of the twine will stand out in every way, and be attracted by the approaching finger. …