Rapid Trigonometrical Indicator Area = B x C / 2 Turn Space To Required Function Formula Is Then Shown [ CIRCULAR CALCULATOR, 2 X CELLULOID OR COMPOSITE WHITE DISCS ROTATING ON CENTRAL METAL PIVOT, SINE & COSINE & TAN ETC MARKED OF, CUT-OUT VIEWING AREA ]

anonymous

Published by Bovril, 1920

About this Item

7.7cm diameter. White celluloid discs rotating about a central pivot, black lettering on top, plain rear, cut-out view area. Very slight browning, faint scuffs to base, few faint fox marks to base else else very clean with chips. VG+. Seller Inventory # 11053

Bibliographic Details

Title: Rapid Trigonometrical Indicator Area = B x C...

Publisher: Bovril

Publication Date: 1920

Binding: Hardcover

Condition: Near Fine