Chaim Selig Slonimski and His Adding Devices

This article presents the accomplishments of Chaim Selig Slonimski (1810-1904), an important but not sufficiently known figure in the history of calculating devices. The authors briefly discuss Slonimski´s life and the recognition he achieved in the 19th century in both Prussia and Russia as well as his patents, financing attempts, similarities to the work of others, and a detailed account of his adding devices of 1845 and 1846. The authors claim that Slonimski invented more calculating devices than it is currently known and present a recently discovered exemplar of one of these devices. They found that Slonimski invented at least two different adding devices and three different multiplying devices and designed a machine to calculate logarithms.