4.6 Gilson, Richardson, USA

The slide rule companies of Gilson and Richardson were both formed in the early part of the 20th century, both were family-owned and operated, initially right from their homes, and both produced metal slide rules.

George W. Richardson, of Chicago, Illinois, USA, copyrighted his first slide rule in 1903, using stainless steel to produce less expensive rules with colorful scales and a unique system for Gauge Marks. He operated his initial business out of his home in Chicago and began selling his rules in 1907, advertising them in the magazine Popular Mechanics by 1909. In 1912 Richardson first published his popular book, The Slide Rule Simplified (by Richardson and J.J. Clark), and later editions included advertising for the Richardson line and other slide rules – particularly those by Gilson!

Meanwhile, Claire Gilson founded the Gilson Slide Rule Company in the basement of the Gilson family home in Niles, Michigan, USA in 1915, just a 100 mile drive to the east of Richardson’s home. Gilson produced circular slide rules with double cursors. These rules were first made of wood with paper overlays, but the wood gave way to steel and then to aluminum by 1919.

Around 1919 Richardson sold his business and retired, continuing to live in Chicago until his death in 1940. There is circumstantial evidence that the Richardson business was in fact sold to Gilson.8

The Gilson company moved to Stuart, Florida in 1927, and was sold to a buyer from New Jersey in the early 1960’s. Gilson slide rules were often sold by others under their own names, including Frederick Post Co., Eugene Dietzgen Co., and others. As a result the name Gilson often does not appear on Gilson slide rules.

Richardson Direct-Reading Model 812

Richardson Direct-Reading Pocket Rule

Gilson Midget Type II (left) and Type VI Version I (right; made for Dietzgen). Gilson Binary Type I.

Gilson Midget Type II (left) and Gilson Binary Type I (right).

Total number of Gilson and Richardson slide rules in the collection: 9.

Maker Model Year Type Mat Size Note
Richardson Direct Reading (812)
1911 L Al 10 Nice condition; early rule
Richardson Direct Reading Pocket
1912 L ss 5 pocket rule; leather pouch in rough condition
Richardson Direct Reading Pocket
1912 L ss 5 pocket rule; slight warping on end of slide; no cursor
Richardson Pantocrat 812
1912 L ss 10 Richardson Rule Works; nice condition though slight warp; SR Simplified c. 1922
Richardson 1776
1918 L ss 10 1776 Simplex; nice condition
Gilson Midget 1919 C Al 12 99 mm Gilson Midget Type II w/ original case
Gilson Atlas
1931 S Al 468 Type II Atlas Calculator
Gilson Midget
1940 C Al 12 made for Dietzgen; 99 mm Gilson Midget Type VI version I
Gilson Binary 1941 C Al 26 Gilson Binary Type I with case


  1. See Michael Konshak, “Richardson and Gilson,” Jour. Oughtred Soc., Vol. 15, No. 1, p. 39 (2006).↩︎