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Bubble Sextant

Catalogue number:
NASM 1966-398

Inscriptions:
"KEUFFEL & ESSER CO. / NEW YORK / 57321 / PATENT PENDING" and "BUBBLE OCTANT MARK II, MOD. 2 / BUREAU OF AERO. U.S. NAVY / SERIAL NUMBER 8 / MADE BY / KEUFFEL & ESSER CO. N.Y."

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 made before the issuance of the Radford-Davis patent in January 1930. It’s provenance is unknown.

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).

L. Radford and N. Davis, "Sextant," U.S. patent #1,743,979

Further Information:

Keuffel & Esser
Aircraft Sextant