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Bubble Sextant

Catalogue number:
AF*59058-N

Inscriptions:
"BUBBLE OCTANT MARK II, MOD. 2 / BUREAU OF AERONAUTICS U.S. NAVY / SERIAL NUMBER 2-29 / MADE BY / KEUFFEL & ESSER CO. / NEW YORK / 57312 / PAT. PENDING"

Discussion:
The Mark II, Model 2 was designed by Noel Davis, modified by Keuffel & Esser, and produced for the U.S. Navy. This example was the 2^nd one made in 1929. P. V. H. Weems donated it to the Smithsonian in 1963.

Ref: T. C. Lonnquest, "Operation and Adjustment of the Mark II Model 2 Octant," Bureau of Aeronautics, Navy Department, Technical Note No. 207 (Nov. 22, 1929).

Lawrence Radford and Noel Davis, "Sextant," U.S. patent #1,743,979

Further Information:

Keuffel & Esser
Aircraft Sextant