Picture a stormy day in Philadelphia, 1752. The clouds come in heavy, and dark over the frontier city of low-slung wooden buildings carved out of the wilderness. Those clouds are ominous, threatening lightning and fire. Most of the residents retreat inside, button up their shutters, and wait for it to pass.
But one man does not seek shelter. That man has been waiting for exactly such a storm to test a theory. That man, not content with wild success as a printer, author, publisher, journalist, politician, and philosopher, is also interested in “natural philosophy,” or what we today would call science. His theory is that lightning is made of the same stuff as electricity, and he has an idea to test it.
With the help of his son he designed and built a kite, a simple kite, with two crossed sticks and a silk handkerchief connected to a twine string. The only thing unusual about the kite is that he tied a very sharp pointed wire to the top of it, and he tied an iron key near the bottom of the twine. The twine, quickly wetted in the rain, would make a fine conductor, conveying the electricity to the key. A metal wire then connected the key to a Leyden Jar, a type of primitive battery. The twine was also connected to a silk string, to be held the man conducting the experiment. He was careful to keep the silk string dry, under the cover of a barn, where he himself stood sheltered. He hoped, correctly, that these last measures would prevent what he called the electric fire from electrocuting him.
The clouds roll in, electric fire crackles in the sky, and the man watches, and waits as his kite flies aloft into the tempest, buffeted to and froe. There is no single dramatic moment where lightning strikes the kite. If it had it’s likely the man would have been killed despite his precautions. But attracting a lightning strike was never his intent. Instead he intended to draw electricity from the clouds gradually, having observed that a sharp pointed wire, as opposed to blunt metal, has a tendency to draw electricity gradually. He watches, as the loose filaments on the twine stand out every which way, having acquired an electric charge.
Throwing caution to the wind, the man approaches and holds his knuckle out to the key. Sure enough, electricity streams freely from the key into his own hand, though not so much as to hurt him. He smiles. He was right. The lightning fire of the clouds is electricity, and he’s proved it. He later confirms that the Leyton Jar is charged with exactly the same type of electrical current previously obtained by the help of a rubbed glass globe or tube. It’s the same thing.
The man was 46-year-old Benjamin Franklin.
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For more, listen to the Podcast episode and check out my book, History Stories for Everyone, where I dive deeper into this and some of history’s other most fascinating and relatable human stories:
