Accession No

6628

Brief Description

circular card calculator, chemical formulator, by Cambosco Scientific Company, U.S.A., 1940 (c)

Origin

U.S.A.; Massachusetts; Boston

Maker

Cambosco Scientific Company

Class

chemistry

Earliest Date

1940

Latest Date

1940

Inscription Date

1940

Material

paper (cardboard); metal (brass)

Dimensions

diameter 180mm

Special Collection

Provenance

Purchased via www.eBay.com on or before 05/01/2016.

Inscription

THE CAMBOSCO CHEMICAL
FORMULATOR
COPYRIGHT 1940 BY
CAMBOSCO SCIENTIFIC CO. - BOSTON

Description Notes

Chemical formulator, circular card calculator, by Cambosco, U.S.A., c. 1940.

Card device for determining compounds as a result of chemical formulator. Consist of two card circles with chemical symbols around the edges joined at the centre by a brass pin that allows the circles to rotate. Cut out slots in the central circle reveal the chemical compound when the user rotates the circles to match the red valence bonds. Chemicals on the outer circle are negative radicals. The centre of the inside circle shows positive radicals. There are two lists linking the chemical name to the symbol. Below this brief instructions are listed on how to use the Formulator.

The rear side shows longer instructions under two subheadings: ‘Notes and Definitions’ and ‘Directions and Examples’. Under the former heading there are definitions and explanations for ‘chemical compounds’, ‘chemical formulas’ and ‘valence’. The latter demonstrates examples for different formulas, including for Calcium Acetate, Sodium Iodide, Cuprous and Cupric Chlorides as well as ‘common names of hydrogen compounds’ and ‘formulas of hypothetical compounds’. There is also an international table of atomic weights and numbers.

U.S. patent no. 2293405

Condition: good, complete. Crease top right of back.

References

Events