Stream of Consciousness: Executions, Frogs' Legs and Salty Electricity

Josh Clark

I found a pretty neat blog called Executed Today. It's pretty much what it sounds like -- entries about the executions, typically by a government, of people throughout history. They're worth following on Twitter too.

One particular entry caught my attention recently, on the 1803 hanging execution of George Foster, a Brit who was convicted of drowning his wife and child in a local canal. Foster would likely have been lost to history had not Giovanni Aldini, the nephew and ardent promoter of Luigi Galvani, an early researcher of electricity. Almost a full century before the Nikola Tesla/Thomas Edison AC/DC tussle, Galvani and Alessandro Volta had a friendlier rivalry about just how electricity was conducted through the body.

This is where George Foster enters the picture. To study the electrical processes of the body, Aldini managed to get permission to apply electrical currents to the recently deceased Foster to see what would happen. Executed Today has an excerpt of the description:

"On the first application of the process to the face, the jaws of the deceased criminal began to quiver, and the adjoining muscles were horribly contorted, and one eye was actually opened. In the subsequent part of the process the right hand was raised and clenched, and the legs and thighs were set in motion. Mr Pass, the beadle of the Surgeons' Company, who was officially present during this experiment, was so alarmed that he died of fright soon after his return home."

All of that, in turn, reminded me of a blog post by Marshall Brain where I first saw this video of frog's legs being stimulated electrically with salt (*possibly not for the squeamish):


Thinking about salt generating electricity led me to this article in Scientific American about generating electricity in Norway using saltwater. I was surprised to find that the electrical outfit wasn't somehow using salt's electrical potential, but rather something akin to osmosis to generate pressure instead. It's pretty ingenious: A container of seawater and a container of freshwater are separated by a membrane that allows water but not salt to pass through. Since homeostasis seems to be the key to the universe, nature is all about dilution and the freshwater travels toward the salty side, it generates the pressure equivalent to a column of water rising 120 feet skyward. This pressure is used to turn a turbine that generates electricity. Pretty neat.