K. Emil TRÖGER manufactured slide rules for specific uses.
This machine is used in medicine to determine the relationship between the volume of the rib cage and its air holding capacity.

The manufacturing of unique slide rules for specific applications gave birth to an industry whose main actors were:

Germany: Aristo (1862 – 1978), Faber Castell (1880 – 1975), Nestler (1878 – 1978)

U.K.: Blundell (1852 – 1966), Carbic (1921 – 1962), Dinsdale (1883 – 1966), Fowler (1910 – 1988)

France: Graphoplex (1950/1990)

United States: Dietzgen (1 ???- 1972), Keuffel & Esser (1886 – 1976)

Japan: Hemmi (1895 – 1973)