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Physical Sciences Collection - Surveying and Geodesy

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Theodolite - click to enlarge

Theodolite - click to enlarge

Theodolite - click to enlarge

Click photos to enlarge.

Theodolite

Catalogue number:
PH*330222

Inscriptions:
"Troughton & Simms LONDON" and "No. 1"

Dimensions:
height 13.5 inches; horizontal circle 8.5 inches diameter; vertical arc 3.75 inches radius; needle 4 inches; telescope 13.875 inches long; hanging level 6.125 inches

Discussion:

This is a standard theodolite as made by Troughton & Simms in the second quarter of the 19th century. The horizontal circle is silvered, graduated to 20 minutes, and read by two verniers with magnifiers to 20 seconds. The vertical arc is graduated and read in a similar manner. The scale "Diff. of Hypo. & Base" that appears on the back of the vertical arc is used to correlate the angle of elevation or depression with horizontal distances when surveying sloping ground. The "No. 1" was probably added by a former owner.

Further Information:

Troughton & Simms
Theodolite

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