Instructions for Otis King's Pocket Calculator

This 16-page pamphlet was printed on light green paper by Carbic Limited, the London manufacturer of the cylindrical slide rule invented by Otis King. It is titled: The Otis King Calculator: Instructions for Use. This form of pamphlet is typically found with King Calculators manufactured later than those that sold with Carbic's eight-page pamphlet. (See 1987.0788.06.) Thus, it was printed no earlier than the late 1960s. This pamphlet did, though, appear before the pound sterling was decimalized in 1971.
An introduction to the instrument has been added, and explanations have been expanded for multiplication and division, logarithms, and understanding the scales. The further examples are nearly identical to those in the earlier form of instructions. The explanations of how to use the logarithmic capabilities of Model L are the same except that the word "unity" has been replaced by the number 1. Discussions of compound roots and approximation have been added, and the explanation of finding the decimal point is expanded.
Reference: Dick Lyon, "Otis King's Patent Calculator,"
Currently not on view
Object Name
date made
ca 1965-1970
Carbic Limited
Physical Description
paper (overall material)
overall: 20.5 cm x 12.8 cm; 8 1/16 in x 5 1/32 in
place made
United Kingdom: England, London
ID Number
accession number
catalog number
Rule, Calculating
Slide Rules
Science & Mathematics
See more items in
Medicine and Science: Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of John White

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