Some early chemical slide rules

Williams, William D.

Permalink

https://hdl.handle.net/2142/126016 Copy

Description

Title

Some early chemical slide rules

Author(s)

Williams, William D.

Issue Date

1992-09-15

Keyword(s)

• History
• Chemistry
• Slide Rule Chem History

Abstract

An article by George Bodner in the Winter 1990 issue of the Bulletin described a rare chem. slide rule designed by Lewis C. Beck and Joseph Henry - their little-known "Improved Scale of Chem. Equiv.". The reader is urged to review that description. The present paper attempts to place this slide rule context by describing its origins, as well as some of its predecessors and successors. The concept of "A Synoptic Scale of Chem. Equiv." was first presented in 1814 by the English chemist, William Hyde Wollaston. Chem. substances were arranged on a scale with distances proportional to the logarithm of their equiv. or combining wts., much as the value of π was marked on the scales of the more conventional slide rules of recent memory. A logarithmic slider, numbered from 10 to 320, allowed quick calcn., via the method of direct and inverse proportions, of the wts. of substances reacting with one another, the quantity of products, or the relative proportions of elements in a compd. Wollaston's original design, measuring 12 by 2.5 in., was marketed in London that same year. A contemporary called it "an instrument which has contributed more to facilitate the general study and practice of chem. than any other invention of man.". It accelerated the acceptance of Dalton's at. theory and promoted chem. as a math. science. Only a few of these original slide rules are still in existence. Some are in European museums. Only two are known to have survived in the United States and both are located at Harvard University.

Publisher

Division of the History of Chemistry

ISSN

1053-4385

Type of Resource

text

Genre of Resource

article

Language

eng

DOI

https://doi.org/10.70359/bhc1992n12p024

Copyright and License Information

Copyright 1992 Division of the History of Chemistry

Owning Collections