How does it work?

From: Steve
Email: steamcar@alphalink.com.au


I have a very old instrument that I think is some kind of calculating device. It is made of brass and is about 180mm by 30mm by 4mm thick. It has scales on both sides and some more that run accross the diagnel. It also opens up like a carpenters rule and there is a leg that sets it to 90deg. Much of the writing is in French. The maker is Cadote and the item is dated Paris 1733. I do not want to sell this but it would be fun to find out what this is and how it works if someone can help. Thanks Steve