overall: .3 cm x 5.5 cm x 14.2 cm; 1/8 in x 2 3/16 in x 5 9/16 in
United States: Texas, Houston
This stainless steel instrument combines the functions of a slide rule, a vernier caliper, and a vernier depth gauge. The moveable calipers are along the top edge. Adjacent to them on one side is a scale four inches long, divided to fortieths of an inch and to sixty-fourths of an inch. Below this are a C scale (on the slide) and a D scale (on the base). The other side has, next to the caliper, is a scale a scale equally divided from 0 to 13. Measuring the diameter of a circular object with this scale, one can read off the circumference. The scale is labeled: CIRCUMFERENCE-INCHES. The slide on this side has scales labeled A and B that are visible through a window in the metal. The scale labeled A is marked: READ (/) CIRCULAR (/) AREAS. It is divided logarithmically and runs from 0 to 4. The scale labeled B is marked: SQUARE AND (/) SQUARE ROOTS. It is divided logarithmically and runs from 0 to 1.
The instrument is stored in a pocket-sized leather case with metal trim. For a folded sheet of instructions, see 1981.0992.19.1.