This has an air-driven gyroscope mounted on the index arm in such a way that
it can be moved up and down, that serves as the artificial horizon. The form was developed in France shortly after World War I, and exhibited at the Paris Air Show in 1920. Beij referred to it as a Derrien sextant. The National Bureau of Standards transferredthis example to the Smithsonian in 1957.
One card in the box reads: "GEORGES DERRIEN Lieutenant de Vaisseau de Réserve."
Another reads: "YVES LE PRIEUR Directeur Technique de la Societé La Precision Moderne 78, rue d’Anjou, Central 19-29." A third indicates that this sextant was tested in November 1920.
Ref: K. H. Beij, "Astronomical Methods in Aerial Navigation," Report of the National Advisory Committee for Aeronautics 198 (1924), p. 21.
Peter Ifland, Taking the Stars (Newport News, 1998), pp. 160-161.
