Mechanical Navigator by F. E. Brandis, Sons and Company

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The mechanical navigator is an analog computing device designed to solve problems in spherical trigonometry arising in navigation. In this form, it was designed for instruction in navigation (another version was designed for use at sea). It allowed a student to compute a ship’s location from two sights in one operation.
The instrument is a mechanical representation of the celestial sphere. A rotating ring mounted vertically on the right side represents the celestial equator. It is calibrated from 0 to 180 by quarter-degrees twice, representing celestial longitude. It also is graduated from 0 to 24 counterclockwise by one minute, and from 0 to XXIV clockwise by one minute. The iron housing inside the vertical circle is calibrated from 0 to 22 by one and labeled by constellation name. A vernier along the edge of this ring marks the meridian of the navigator.
The instrument has two concentric rings which rotate in perpendicular planes. The outermost represents an hour circle. It is calibrated from 0 to 90 by quarter-degree, four times, and also bears hour lines. The inner ring represents the horizon circle. In addition to degree scales like those of the hour circle, it has is letters for eight cardinal points with sixteen subdivisions between each letter.
A quadrant affixed perpendicular to the horizon ring, has scales calibrated scale along both sides that run from 0 to 90 degrees, divided to quarter degrees and marked every ten degrees. These represent degrees of latitude. All of these parts rotate on pivots. There are screws for setting the circles.
The iron base, in the shape of a “T,” has handles at each end. A prior owner made a fitted wooden base for the navigator. The base has two boards with a space between them. Two removable wooden rods labeled in pencil “Left” and “Right” rest between the boards. A mark engraved on the vertical ring reads: F. E. BRANDIS, SONS & CO. (/) BROOKLYN, N.Y. (/) 2877.
Frederick Ernest Brandis (1845-1916) was a German immigrant who began making and importing instruments in 1871. From the name of the firm, the instrument was made between 1890 and 1916. An eighteen-page typescript of the company’s instructions for using the mechanical navigator is stored in the accession file. According to an account of the instrument published in Engineering News in 1914, the mechanical navigator sold for $2400.
Compare PH*307189.
Brandis & Sons Mfg. Co., Instruments of Precision . . . Catalogue No. 20 (Brooklyn, New York, n.d.), pp. 294-297.
"Instrument for Solving Problems of Navigation," Scientific American (July 16, 1910): 44,56,57.
“An Instrument for Solving Spherical Triangles Mechanically,” Engineering News, vol. 71 #4, January 22, 1914, pp. 180-181.
Currently not on view
date made
F. E. Brandis, Sons and Company
place made
United States: New York, New York
United States: New York, Brooklyn
Physical Description
metal (overall material)
wood (base material)
overall: 26 cm x 44.4 cm x 27.7 cm; 10 1/4 in x 17 15/32 in x 10 29/32 in
ID Number
accession number
catalog number
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Spherical Trigonometry
Data Source
National Museum of American History, Kenneth E. Behring Center


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