Sphere's Slide Rule Universe is a repository for information about slide rules, pictures, history and links to sellers, other sites and experts, and an on-line store. Located in Kelowna, BC, CANADA.

The Museum of HP Calculators Slide Rules In 1614, John Napier discovered the logarithm which made it possible to perform multiplications and divisions by addition and subtraction. (ie: a*b = 10^(log(a)+log(b)) and a/b = 10^(log(a)-log(b)).) This was a great time saver but there was still quite a lot of work required. The mathematician had to look up two logs, add them together and then look for ...

Personal collection of slide rules, along with various resources including general background information, manuals, books, restroration tips, links and more.