Berger & Sons Transit

Description
This "Complete Engineers' and Surveyors' Transit" is marked "C. L. Berger & Sons, Boston, U.S.A. 8879" and "PAT'D APRIL 28-1896." Swarthmore College ordered it from Berger in November 1911. The horizontal circle is of solid silver, with opposite verniers placed at 35 degrees to the line of sight, and reading to 30 seconds of arc. The vertical circle is of solid silver, read by vernier to single minutes, and protected by an aluminum guard. The standards have a cloth finish. Berger noted that it was "designed for engineering work of a high class, such as is required in bridge building, water works, and for city and land surveying." New, it cost $255.
It is difficult to know how to interpret the patent reference in the inscription. On April 28, 1896, C. L. Berger received a patent (#559,117) for a Surveyor's Transit with an auxiliary telescope that could "be used for the ordinary plane surveying, and also for mine surveying and similar purposes." This instrument is not of that sort.
Ref: C. L. Berger & Sons, Hand-Book and Illustrated Catalogue of the Engineers' and Surveyors' Instruments of Precision (Boston, 1912), pp. 142-146.
Chicago Steel Tape-Berger Instruments (Document Management Systems, 1995), Book 27, p. 33.
Location
Currently not on view
maker
C.L. Berger and Sons
place made
United States: Massachusetts, Boston
Measurements
overall: 14 in; 35.56 cm
horizontal circle: 6 1/4 in; 15.875 cm
needle: 4 1/4 in; 10.795 cm
verticle circle: 5 in; 12.7 cm
telescope: 11 in; 27.94 cm
hangling level: 5 in; 12.7 cm
ID Number
1986.0668.01
accession number
1986.0668
catalog number
1986.0668.01
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History, Kenneth E. Behring Center

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