The Calcumeter

Coplanar toothed wheel adder

since 1901

The calcimeter was designed by James J. Walsh from Elizabeth in New Jersey, who also holds the corresponding patent. From about 1901 on, the machine was manufactured by Herbert North Morse in Trenton, New Jersey, whereby the inventor was also initially named Walsh. Otnes assumes that the calculator was on the market until 1920. The sales figures of the stable and reliable machine were considerable: 60,000 copies are said to have been sold by 1910. A brochure from 1907 describes over 12 models in different sizes (number of discs). All of them have a simple tens transfer, in the case of fractional rake discs the corresponding transfer. This model has five decimal places. Between the second and the third digit there is a hyphen, which can be used as a decimal point. The disks can only be rotated in one direction, the zero position is marked with a '0' on each disk. With the help of a pencil the summands on the disks are adjusted manually. Deletion can only be done by entering the complement of nine. An improved model has a zeroing disc (FDM 8911).