Usage/History: The theodolite is a surveying instrument
used for accurately measuring angles in both the vertical and
horizontal planes using a telescope and graduated circles. The
American transit is a slight variation in which the standards
for the telescope are taller to enable the telescope to be completely
revolved or transited in the vertical plane. The terms
theodolite and transit are often used interchangably by American
instrument firms and users.
Some contemporary/early descriptions of the transit and its
use are provided below:
Description: An oval brass tag, attached with brass
pins to the top of the mahogany
case, is stamped: HUMBOLDT S-T-C / 557, the transit itself
is engraved HSC 557.
Bibliolgraphy:
Kiely, Edmond R. Surveying Instruments: Their History.
Carben Surveying Reprints, Columbus (1979).
Smart, Charles E. The Makers of Surveying Instruments
in America Since 1700. Regal Art Press, Troy (1962).
