Model Brunsviga 20 calculating machine, serial no. 146309, supplied by Block and Anderson Limited, Darlington, County Durham, England and made by Grimme, Natalis and Co. A. G., Braunschweig, Germany, 1931-1939

Science involves calculation as well as experiment and theorising. Gradually improving equipment for calculation was a feature of twentieth-century science, from calculators at the beginning to computers at the end. A mechanical calculator like this one was still being used in the 1950s to study and analyse the growing cases of lung cancer in Britain.

Brunsviga was the brand name of a popular series of calculating machines produced by the German manufacturer Grimme, Natalis and Company from the 1890s onwards.