Brandis termed this a "Mechanical Navigator," noting that it is a model of the celestial sphere with 3 vertices: the pole, the zenith, and the observed body. It was designed to eliminate the mathematical labor involved in navigation, and was said to be "sufficient to be able to find, by a single operation, a ship’s place from two sights, also making allowance for the ship’s run." Brandis advertised the instrument in 1923 "As Made for Universities where Navigation is Taught," suggesting that its complexity probably kept it from being of much use to a practical navigator.
The Mechanical Navigator is made of cast iron, brass, and wood. It has
several interlocking discs, each graduated to different scales. A large disc
towards the top of the instrument represents the equator and is made up of two silver circles. One circle is graduated in time and the other in degrees
longitude. The knob in the center of the two circles looks to the position of
the celestial body to be sighted. Another graduated circle represents the
horizon and can pivot northward or southward. A circle at the bottom of the
instrument is set to the exact latitude of the ship, and a spherical compass
rests in the middle.
Ref: Brandis & Sons Mfg. Co., Strictly First-Class Instruments
of Precision…Catalogue No. 20, (1923), p. 294-297.
