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Bubble Sextant - click to enlarge

Bubble Sextant - click to enlarge

Bubble Sextant - click to enlarge

Click image to enlarge.

Bubble Sextant

Catalogue number:

"U.S. ARMY AIR CORPS AIRCRAFT OCTANT / TYPE NO. A-8 SERIAL NO. A.C.40-10 / SPECIFICATION NO. 27914 / ORDER NO. AC-144464 / MFR’S ASS’Y DWG. NO. 277728 / BAUSCH & LOMB OPTICAL CO. / ROCHESTER, N.Y. U.S.A." and "U.S. PATS. 1,531,615; 1,674,550; 1,703,705; 2,080,851"

Bausch & Lomb made this instrument for the U.S. Army shortly before America entered World War II. It is based on the Bureau of Standards design, but with an improved method for illuminating the bubble and the marking pad designed by George Gallasch and Henry Kurtz, both of Bausch & Lomb. It also has a mechanical averager that can handle eight consecutive readings. Thomas L. (Tommy) Thurlow of the Army Air Corps filed a patent application for an averager on August 3, 1937, but was scooped, by one day, by P. F. Everitt of Henry Hughes & Son, the leading British manufacturer of nautical and aeronautical instruments.

Ref: Operation, Service and Overhaul Instructions for Aircraft Sextants Types A-6, A-6A, A-8 and A-8A (Bausch & Lomb) (Army Air Corps, 25 August 1943, revised 23 January 1946); the original restrictions on this publication were lifted after the war.

Bausch & Lomb at War (ca. 1943), p. 20.

G. B. Gallasch and H. F. Kurtz, "Sextant," U.S. patent #2,080,851.

Further Information:

Bausch & Lomb
Aircraft Sextant