Otis King's Pocket Calculator Model L Cylindrical Slide Rule

Description:

This six-inch cylindrical slide rule consists of a chromium-plated holder, a metal cylinder that slides into the holder, and a black metal tube that fits around and slides up and down on the cylinder. The rule is ten inches long when extended and equivalent to a linear slide rule 66 feet in length. Two short white lines on the tube and a black mark on the chrome cap at the end of the cylinder serve as the indicator. A paper spiral logarithmic scale is attached to the top half of the holder. A second, linear and logarithmic, paper scale is attached to the cylinder. The logarithmic scales are used to multiply and divide, and the linear scale is used to find logarithms.

The end of the cylinder is engraved: MADE IN (/) ENGLAND. At the top of the cylinder is printed: PATENT No 183723. At the bottom of the cylinder is printed: OTIS KING'S POCKET CALCULATOR; SCALE No 430. The top of the scale on the holder is printed: SCALE No 429; COPYRIGHT. The bottom is printed: OTIS KING'S PATENT No 183723. The end of the holder is machine engraved: T/0503. Engraved by hand (and upside-down to the serial number) is: C73.

The instrument is stored in a rectangular black cardboard box. A label on one end reads: Otis King's (/) Calculator (/) Model "L" (/) No. T0503. The slide rule arrived with instructions, 1987.0788.06, and an advertising flyer, 1987.0788.07. See also 1989.3049.02 and 1981.0922.09.

Otis Carter Formby King (b. 1876) of Coventry, England, received a British patent (183,723) for this instrument on August 31, 1922, and in 1923 he received patents 207,762 and 207,856 for improvements to the slide rule. From London, King filed a U.S. patent application, which he assigned to Carbic Limited, the London manufacturer of the slide rule, when that patent was granted in 1927. With co-inventor Bruce Hamer Leeson, King received U.S. Patent 1,820,354 for an "electrical remote control system" on August 25, 1931.

The serial number indicates that this example of Otis King's calculator was manufactured around 1960 to 1962. Howard Irving Chapelle (1901–1975), a naval architect, maritime historian, and curator of what was then the National Museum of History and Technology, donated it to the Smithsonian around 1969 to 1970.

References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 274, 281; Otis Carter Formby King, "Calculating Apparatus," (U.S. Patent 1,645,009 issued October 11, 1927); Richard F. Lyon, "Dating of the Otis King: An Alternative Theory Developed Through Use of the Internet," Journal of the Oughtred Society 7, no. 1 (1998): 33–38; Dick Lyon, "Otis King's Patent Calculator," http://www.svpal.org/~dickel/OK/OtisKing.html.

Date Made: 1960-1962

Maker: Carbic Limited

Location: Currently not on view

Place Made: United Kingdom: England, London

Subject: InventionRule, CalculatingMathematics

Subject:

See more items in: Medicine and Science: Mathematics, Science & Mathematics, Slide Rules

Exhibition:

Exhibition Location:

Credit Line: Gift of Howard I. Chappelle

Data Source: National Museum of American History

Id Number: 1987.0788.01Catalog Number: 1987.0788.01Accession Number: 1987.0788

Object Name: slide rule

Physical Description: chromium (overall material)paper (part material)Measurements: overall: 17 cm x 4 cm x 3.7 cm; 6 11/16 in x 1 9/16 in x 1 15/32 in

Guid: http://n2t.net/ark:/65665/ng49ca746aa-98e6-704b-e053-15f76fa0b4fa

Record Id: nmah_1214638

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