Smithsonian - National Museum of American History, Behring Center

Physical Sciences Collection - Surveying and Geodesy

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Altitude and Azimuth Instrument
Chain, Tape and Base Bar
Compass, Pocket
Compass, Railroad
Compass, Solar
Compass, Surveyor's
Cross, Surveyor's
Electromagnetic Distance Measurement (EDM)
Holland Circle
Range Finder
Repeating Circle
Transit and Equal Altitude
Transit, Geodetic
Universal Instrument
Vertical Circle
Zenith Telescope


Solar Compass

A solar compass is a railroad compass with a solar attachment that allows surveyors to determine the north direction by reference to the sun rather than by reference to the magnetic needle. The form originated with William Austin Burt, a United States Deputy Surveyor who began surveying government lands in Michigan in 1833. In 1835, while working in an area of Wisconsin where there were large deposits of iron ore, Burt experienced great difficulty in using his standard vernier compass. By December he had roughed out his ideas for a solar compass, and asked William J. Young in Philadelphia to make a model that he could submit to the Patent Office. Burt received a patent (#9428) the following year, and the Franklin Institute awarded him the Scott’s Medal for this "ingenious" instrument. But, as the solar compass was not yet serviceable, Burt went back to the drawing board. In 1840, confident that he had solved all the problems of his design, Burt asked Young to produce solar compasses. In 1850, the year that Burt’s patent expired, the General Land Office adopted the solar compass as a standard instrument for all major boundary lines in regions of magnetic disturbance, and demand rose accordingly. Claiming that he had never received even $300 "for his right in said invention," Burt petitioned Congress to renew his patent. But to no avail.

Burt’s solar apparatus consists of three arcs: one for setting the latitude of the land to be surveyed; one for setting the declination of the sun; and one for setting the hour of the day. In the latter half of the 19th century, several instrument makers offered solar attachments of this sort that could be used with transit instruments.


William A. Burt, Description of the Solar Compass (Detroit, 1844).

William A. Burt, A Key to the Solar Compass, and Surveyor’s Companion (Philadelphia, 1855).

John Burt, History of the Solar Compass Invented by Wm. A. Burt (Detroit, 1878).


Gurley (1860)
Gurley (about 1880)
Young (1848)
Young (about 1840)