This sextant was made for emergency use during World War II. The body is
plastic. The scale is graduated every degree from -5o to +140o and read by vernier to 3 minutes of arc. The box is marked "U.S. MARITIME COMMISSION / CRUVER MFG. CO." The Cruver Manufacturing Co., in Chicago, began making novelty objects of plastic in the early 1900s. The U.S. Maritime Commission (fl. 1936 to 1950) was responsible for further developing and maintaining a merchant marine for the promotion of American commerce and defense.
Ref: W. J. Eckert, Lifeboat Sextant. Instructions for Use in Finding
Latitude and Longitude Together with Simple Sailing Instructions (U.S. Naval Observatory, 1944).