Welcome to the wonderful world of the slide rule.
Invented by William Oughtred in 1622, it consists of two divided scales, one fixed and one movable with a sliding window called a cursor.
Slide rules were the primary tool for performing multiplication, division and other scientific functions up through the 1960s until the development of the electronic calculator arrived.
They come in all shapes and sizes, straight, circular and cylindrical slide rules, all collectible.
Major manufacturers included Keuffel and Esser, Pickett, Gilson, Dietzgen, Post (which became Teledyne), Faber-Castell, Aristo, Unique plus others.
Early slide rules were made of wood and celluloid, while later ones tended to be plastic or metal.
We’ve a range available for sale on this site, as well as an expanding knowledge base for collectors and enthusiasts everywhere.