Our church had a yard-sale today, to support the upcoming youth-group mission trip. Now, I'm not generally a big yard sale fan, but I do try and support the church. So I took my son and we headed over. He found all sorts of fun junk, and I found this:
For thise youngsters out there, it's a Pickett Model N-531-ES slide rule. The "scientific calculator" that predates calculators. Looks like it is from 1960-1962. Complete with all the documentation, and original box. A wonderfully geeky find for any engineer.
Now, I'm not (quite) old enough to have ever been a slide rule expert, but they did teach us how to use one in middle-school. Probably just to make us suffer, as scientific calculators had already taking over. My cheap plastic one is long gone.