Chemical Match Output

Number:23

Maker:Keuffel & Esser 4160 Chemist
PHOTO

Length: 25 cm

Gauge Marks:

Scales Front: 2 chemical scles C = D

Scales Back: i2 chemical scales CI = D

Info: Paul Tarantolo Collection
Discussed in Slide Rule Gazette. Issue 19 Autumn 2019 Pg 129 (See Refernces at the Top of the Home Page)
which discussed the movement of the mark for Antimony (Sb) as its atomic mass changes.
Chemical slide rule designed by Raymond Harmon Ashley (ca. 1895-), a chemist teaching at the University of Maine.
Further details from https://americanhistory.si.edu/collections/search/object/nmah_3026 and http://acshist.scs.illinois.edu/bulletin_open_access/num12/num12%20p24-29.pdf