THE MESSUM NAUTICAL PROTRACTOR
Stock Number: 9394
For sale, antique nautical protractor of thermoplastic or celluloid, fully engraved with various scales for maritime calculations.
7 inches (18 cm)
Country of manufacture
UK and Ireland
THE MESSUM NAUTICAL PROTRACTOR, English, c.1910, signed “Cary, London, Regd. No. 475601.” Made of thermoplastic or heavy celluloid, 7″ overall, the protractor is engraved on both sides with numerous scales in black and red. Included are a “Masthead Angle Table” and a “Tide Scale For 6 Hr. Tide.” The inventor was apparently Cmdr. Stuart V.S.C. Messum, author of Hydrographic Surveying in 1910. Messum does discuss various scales and designs of protractors, as well as the practicality of surveying by measuring the angular height of the top of a ship’s mast above water line. He also devotes many pages to tidal calculations. A rare mathematical instrument, with complex calibrations, in fine condition.
Ask the Dealer
David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at email@example.com.