Two Chemical Slide Rules : Notes from the Oesper Collections, No. 44, May/June 2017

Closeup of part of the Ch scale for the circa 1960 Hemmi 257 chemical slide rule.
Closeup of part of the Ch scale for the circa 1960 Hemmi 257 chemical slide rule.

Issue 44 gives a glimpse of two classic chemical slide rules found in the Oesper Collections, one dating from 1814 and the other from 1960.

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