I have one. I don't know what it's called or what I am supposed to do with it. It was my grandaddy's, but he was a lawyer.
BTW, I taught Anthony, our summer intern, how to use a planimeter earlier this week. He said "That's dumb, just use the computer." I told him to show me how he knows the computer is right. Ahhh, kids.
The difference between the older generation and the younger generation... the younger generation does math in their head and checks it with a calculator... the older generation does math on a calculator and checks it in their head...
It's called a ruling pen