Accession No
6258
Brief Description
Otis King’s Patent Calculator, cylindrical slide rule, Model E, in fitted box with instruction manual and promotional material, by Carbic Ltd., English, mid-20th Century
Origin
England; London; 51 Holborn Viaduct, E.C.1
Maker
Carbic Ltd.
Class
calculating
Earliest Date
1940
Latest Date
1971
Inscription Date
Material
metal (steel; brass); wood (or card); paper; fabric (velvet or felt?)
Dimensions
Box - Depth: 40mm, Width: 50mm, Length: 180mm Calculator - Diameter: 30mm, Length: 165mm
Special Collection
Provenance
Donated by a relative of the collector, 27/03/2009. From the collection of calculators of Francis Leslie Freeland (1905-1995) of Darwin College.
Inscription
[on base of calculator]
5063
[on inside lid of box]
Otis King Patent Calculator
Patentees & Sole Manufacturers, Carbic Limited, 51 Holborn Viaduct, London, E.C. 1.
Description Notes
Otis King’s Patent Calculator, cylindrical pocket slide rule with helical scales, model E, in fitted box with instruction manual and promotional material, by Carbic Ltd., English, mid 20th century.
The calculator is a white-metal cylinder that consists of three moving parts. The first is to be held, and contains the lower scale (weight); the second separates to two outer slides and holds them together; the third piece contains the upper scale (money - pound sterling) and can be moved and adjusted depending on the sum being undertaken. The second piece forms a sheath around the two labelled slides, at each end of it are small arrows inscribed into the surface, these are used when calculating. The top of the third piece has a small ring through which a chord could be fastened. At the top there is also a serrated edge to help with grip when pulling the slide-rule out.
The box is made of wood or card covered in a black material. It has two brass hinges and a brass spring loaded clasp that holds the lid shut. It is lined with a white material in the lid and dark blue velvet in the base. The base is fitted to the contours of the slide-rule.
This particular type of Otis King Calculator, Model E, is notable because its scales are designed to be used in calculations that combine money and weight. The scale on the upper cylinder is graduated with a money scale in units of pounds, shillings and pence, ranging from 1d to £100. The scale on the lower cylinder (”The Holder”) is graduated with a weight scale in units of ounces and pounds, ranging from 1oz. to 156lbs.
References
Events
Description
Before the advent of the pocket electronic calculator in the 1970s, the slide rule was the most common tool for calculation used in science and engineering. Used for multiplication and division, the slide rule uses the logarithmic scale, a calculation method invented in 1614 by John Napier. Cylindrical slide rules such as Otis King’s Patent Calculator allow calculations to be done that would otherwise require a linear slide rule of many times its length. This made them popular for their portability.
This particular type of Otis King Calculator, the Model E, is notable because its scales are designed to be used in calculations that combine money and weight. The scale on the upper cylinder is graduated with a money scale in units of pounds, shillings and pence, ranging from 1d to £100. The scale on the lower cylinder (”The Holder”) is graduated with a weight scale in units of ounces and pounds, ranging from 1oz. to 156lbs.
The instructions that come with the calculator boast that “Otis King’s Patent Calculator will solve, in a few seconds, all problems combining money and weight. Given the Pound Sterling value of any known weight, the value of any other weight or the weight of any other value, can be ascertained in one operation. It is invaluable for arriving at cost and selling prices, and the checking of invoices, etc.”
16/04/2009
Created by: Joshua Nall on 16/04/2009
FM:46738
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