Richardson Direct Reading Slide Rule

In the late 19th and early 20th centuries, several American inventors strove to produce inexpensive slide rules. One of them was George Washington Richardson (about 1866–1940), who was born in the United States of British parents. He served as a chief electrician in the U.S. Navy. Census records indicate that by 1910, he was living in Chicago with his wife, young son, and wife's parents and working as an engineer in a Chicago public school. Seeking to better himself, Richardson enrolled in an International Correspondence Schools (I.C.S.) course in electrical engineering in 1901, receiving his diploma in 1904. He copyrighted his first slide rule in 1903, began selling it in 1907, and advertised it in Popular Mechanics by 1909. Working with mechanical engineer John Jesse Clark, the dean of the faculty at I.C.S., he developed a range of slide rules and took out patents in 1911, 1912, and 1918. By 1920, Richardson sold his business to the Gilson Slide Rule Company, purchased an expensive automobile, and retired. He remained in Chicago until his death.
This roughly made 11-inch simplex slide rule has an aluminum frame that holds two pieces of a white celluloid base and a white celluloid slide. The top of the base has an A scale, the bottom has a D scale, and the slide has B and C scales. The A and B scales are logarithmically divided from 1 to 100, and the C and D scales are logarithmically divided from 1 to 10. Various letters are revealed in keyholes in the upper left and lower right corners of the base. These letters correspond to a conversions of units table on paper glued to the back of the rule. An aluminum indicator has a plastic window and is marked: PAT.PEND.
The top of the base is marked: GEO. W. RICHARDSON'S DIRECT READING SLIDE RULE. The bottom of the base is marked: ADDRESS : 4212, 24TH PLACE, CHICAGO, ILL. The back has instructions and is marked: Copyright 1903 By George W. Richardson. The slide rule sold with an instruction booklet for $1.50 in 1909, and with a modified indicator for $2.00 in 1910.
References: Mike Konchak, "Geo. W. Richardson Rule Works,"; Bruce E. Babcock, "George Washington Richardson's Direct Reading Slide Rules," Journal of the Oughtred Society 1, no. 1 (1992): 9–13; George W. Richardson, "New Slide Rule," Popular Mechanics 12 (October 1909): advertising section, 122; "Slide Rule for Mathematical Calculations," Popular Electricity and the World's Advance 2, no. 11 (March 1910): 774; George W. Richardson, "A Direct Reading [Slide] Rule," Modern Machinery 24, no. 12 (April 1910): 330–331; "Direct Readings from a Slide Rule," Practical Engineer 14, no. 8 (August 1910): 502; "Circles and Squares: Use of the Double Scale for Boiler Problems" Practical Engineer 14, no. 11 (November 1910): 701; George W. Richardson, "Slide Rule" (U.S. Patent 982,876 issued January 31, 1911), "Slide Rule" (U.S. Patent 1,021,484 issued March 26, 1912), and "Slide Rule" (U.S. Patent 1,260,454 issued March 26, 1918). On Richardson and Gilson, see also MA*316707.
Currently not on view
Object Name
slide rule
date made
ca 1909
George W. Richardson
Physical Description
plastic (part material)
aluminum (overall material)
paper (part material)
overall: 28 cm x 4.2 cm x .4 cm; 11 1/32 in x 1 21/32 in x 5/32 in
place made
United States: Illinois, Chicago
ID Number
accession number
catalog number
Rule, Calculating
General Calculation
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center


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