Thursday, November 24, 2011

Dr. Franklin’s Turkey Hotline

In 1750, Benjamin Franklin was deep in his investigation of electricity. He told a correspondent at the Royal Society in London that he planned to try killing a turkey with [what we’d now call] the static charge from two big glass jars.

On 25 December, Franklin wrote to his brother John in Boston describing the result of that experiment:
Two nights ago being about to kill a Turkey by the Shock from two large Glass Jarrs containing as much electrical fire as forty common Phials, I inadvertently took the whole thro’ my own Arms & Body, by receiving the fire from the united Top Wires with one hand, while the other held a Chain connected with the outsides of both Jars.

The Company present (whose talking to me, & to one another I suppose occasioned my Inattention to what I was about) Say that the flash was very great & the crack as loud as a Pistol; yet my Senses being instantly gone, I neither Saw the one nor felt heard the other; nor did I feel the Stroke on my hand, tho’ I afterwards found it raised a round swelling where the fire enter’d as big as half a Pistol Bullet by which you may judge of the Quickness of the Electrical Fire which by this Instance seems to be greater than that of Sound Light & animal Motion Sensation.

What I can remember of the matter is, that I was about to try whether the Bottles or Jars were fully charged, by the Strength & Length of the stream issuing to my hand, as I comonly used to do, & which I might Safely enough have done if I had not held the chain in ye. other hand; I then felt what I know not how well to describe; a universal Blow thrôout my whole Body from head to foot which seem’d within as well as without; after which the first thing I took notice of was a violent quick Shaking of my body which gradually remitting, my sense as gradually return’d, & then I thôt the Bottles must be discharged but could not conceive how, till at last I Perceived the Chain in my hand, and Recollected what I had been About to do:

that part of my hand & fingers which held the Chain was left white as tho’ the Blood had been Driven Out, and Remained so 8 or 10 Minutes After, feeling like Dead flesh, and I had a Numbness in my Arms and the back of my Neck, which Continued till the Next Morning, but wore off. Nothing remains now of this shock but a Soreness in my breast Bone, which feels as if it had been Bruised. I did not fall but suppose I should have been knocked down, if I had received the Stroke in my head. The whole was over in less than a minute.
Franklin wanted his brother to warn young James Bowdoin, whom he had just sent a bunch of electrical writings, about this possible danger. The letter survives in the Bowdoin Papers at the Massachusetts Historical Society; you can see it here.

Undaunted, Franklin returned to his experiments and sent a full report to the Royal Society, where it was lost but not before being summarized for its Philosophical Transactions:
He made first several experiments on fowls, and found, that 2 large thin glass jars gilt, holding each about 6 gallons, were sufficient, when fully charged, to kill common hens outright; but the turkeys, though thrown into violent convulsions, and then lying as dead for some minutes, would recover in less than a quarter of an hour. However, having added three other such to the former two, though not fully charged, he killed a turkey of about ten pounds weight, and believes that they would have killed a much larger. He conceited, as himself says, that the birds killed in this manner eat uncommonly tender.
Those experiments led Franklin becoming a Fellow of the Royal Society in 1756.

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