Artifact Details

Title

Calculex Patent Circular Slide Rule

Catalog Number

X171.83

Type

Physical object

Date

ca 1920s

Manufacturer

J. Halden and Company

Place Manufactured

U.K.

Dimensions

1/2 x 2 3/8 x 3 in.

Description

From Computer Museum report, Summer 1983: "Manufactured by J. Halden and Company, London, during the 1920s, the pocket watch style calculator and slide rule has two logartithmic scales, A and B, on one side for multiplication, division and proportion which correspond to the A and B scales of an ordinary slide rule. Around the outer edge is a scale of logarithms read by a cursor. The inner circles contain a scale of square root. The other side of the Calculex contains A and B scale for inverse proportions."

Category

Pre-computer: slide rule

Credit

Gift of Tom McIntyre

Lot Number

X171.83