Thacher's Calculating Device

Title

Thacher's Calculating Device

Subject

Calculating Devices

Description

This early relative of the slide rule has a cylinder 4 in. in diameter and 18 in. long that rotates and slides in and out between the array of twenty equally-spaced parallel bars. The bars have a scale with numbers spaced logarithmically, as on a slide rule’s multiplication scales. The cylinder also has a logarithmic scale engraved lengthwise on it. The net effect is that of a very long slide rule, allowing calculations accurate to four to five digits to be made. In 1934 this instrument was sold by Keuffel and Esser for $80.00.

Source

Property of the W&L Physics & Engineering Department

Files

http://s3.amazonaws.com/omeka-net/2253/archive/files/d94d78df3643c79ac43e3b47ca786ab6.JPG

Citation

“Thacher's Calculating Device,” Digital Exhibits at Washington and Lee University Library, accessed November 20, 2017, http://omeka.wlu.edu/items/show/174.