  Crow's foot zinc.
The February 2007 issue of Popular Science magazine (for which I write a monthly column has my article about making an antique-style "gravity cell", a type of battery made with a solution of copper sulfate and an electrode made of cast zinc. These were known a hundred years ago as "crow's foot zincs", and were available at that time in any corner general store. But these batteries have not been used for at least 60 years, and not even on eBay can you buy a crow's foot zinc, so I was forced to machine a graphite mold to use to cast my own brand new copies, based on a photograph I found on the internet. (Within days of the article reaching subscribers I got an email from someone wondering where I got the crow's foot zincs, and if they could get some too. I had to tell them that I've probably made the first new ones manufactured in many decades, and so far as I know there is simply no source for them. Except, of course, my little graphite mold.)
Actually there's no need for such a fancy shape of electrode, any old hunk of zinc would work reasonably well. I was just showing off by making a replica of an antique style electrode: I wanted the pictures to look pretty in the magazine.
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 1 December, 2006
Text Updated: 14 January, 2007
Price: $0.10
Size: 3"
Purity: 99.99%
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