Photo of an Arithometer with two slides

A photograph of Science Museum object 1909-167 with a caption that reads 'S.M.48 Arithmometer with two slides. This shows a modern example of the Thomas de Colmar example type of calculating machine. There are two slides which can work together in four ways. Both can be additive; both subtractive; upper additive, lower subtractive; upper subtractive, lower additive. E.10 - 1909 Made by Spitz & Co of Berlin'.