Universal Magnetometer with Earth Inductor

Description:

This instrument combines a theodolite to determine latitude, azimuth, and time; a magnetometer to determine declination and horizontal intensity; and an earth inductor and galvanometer to determine dip. The inscriptions read "Edelmann, Munchen" and "U.S.C. & G.S. No. 22."

The form was designed in the early 1890s by Heinrich Wild, a Swiss scientist who spent much of his career directing the Russian magnetic and meteorological observatory at Pavlovsk. This example was built by Max Thomas Edelmann (1845-1913), an accomplished instrument maker in Munich. Both men had made major contributions to the development of earth inductors. The U.S. Coast and Geodetic Survey installed instruments of this sort in its several magnetic observatories around 1901. This one was used at Honolulu until 1927.

The horizontal circle is 30 cm in diameter and read directly to 2 seconds by micrometer microscopes.

Ref: H. Wild, "Beiträge zur Entwicklung der magnetische Beobachtungsinstrumente," Repertorium für Meteorologie (1893), vol. 17, no. 6.

M. Th. Edelmann, "On the Construction of Earth-Magnetic Instruments," Weather Bureau Bulletin 11 (1893): 522-550, on 528-529.

H. Wild, "Theodolit für magnetische Landesaufnahmen," Vierteljahrschrift der Naturforschenden Gesellschaft in Zürich (1896), vol. 2, pp. 149-173.

Daniel Hazard, Results of Observations Made at the Coast and Geodetic Survey Magnetic Observatory Near Honolulu, Hawaii, 1902-1904 (Washington, D.C., 1909), pp. 12-13.