Otis Carter Formby King (1876–1944) was an electrical engineer
in London who invented and produced a cylindrical
slide rule
The slide rule is a mechanical analog computer which is used primarily for multiplication and division, and for functions such as exponents, roots, logarithms, and trigonometry. It is not typically designed for addition or subtraction, which is ...
with helical scales, primarily for business uses initially. The product was named Otis King's Patent Calculator, and was manufactured and sold by Carbic Ltd. in London from about 1922 to about 1972.
With a
log-scale decade length of 66 inches, the Otis King calculator should be about a full digit more accurate than a 6-inch pocket slide rule. But due to inaccuracies in tic-mark placement, some portions of its scales will read off by more than they should. For example, a reading of 4.630 might represent an answer of 4.632, or almost one part in 2000 error, when it should be accurate to one part in 6000 (66"/6000 = 0.011" estimated interpolation accuracy).
The
Geniac
Geniac was an educational toy billed as a " computer" designed and marketed by Edmund Berkeley, with Oliver Garfield from 1955 to 1958, but with Garfield continuing without Berkeley through the 1960s. The name stood for "Genius Almost-automatic C ...
brand cylindrical slide rule sold by Oliver Garfield Company in New York was initially a relabelled Otis King; Garfield later made his own, probably unauthorized version of the Otis King (around 1959). The UK patents covering the mechanical device(s) would have expired in about 1941–1942 (i.e. 20 years after filing of the patent) but copyright in the drawings would typically only expire 70 years after the author's death.
Patents
* UK patent GB 207,762 (1922
* UK patent GB 183,723 (1921
* UK patent GB 207,856 (1922
* US patent US 1,645,009 (1923
* Canadian patent CA 24198
* Canadian patent CA 24107
* French patent FR56998
* French patent FR57661
* German patent DE 41881
See also
*
Bygrave slide rule
The Bygrave slide rule is a slide rule named for its inventor, Captain Leonard Charles Bygrave of the RAF. It was used in celestial navigation, primarily in aviation. Officially, it was called the A. M. L. Position Line Slide Rule (A.M.L. for Ai ...
*
Fuller's cylindrical slide rule
The Fuller calculator, sometimes called Fuller's cylindrical slide rule, is a cylindrical slide rule with a helical main scale taking 50 turns around the cylinder. This creates an instrument of considerable precision – it is equivalent to a ...
External links
Dick Lyon's Otis King pages
References
{{DEFAULTSORT:King, Otis
1876 births
1944 deaths
English inventors
Mechanical calculators
Logarithms
English inventions
Analog computers