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Theodolite - click to enlarge

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Theodolite

Catalogue number:
PH*318454

Inscriptions:
"Secretan a Paris"

Dimensions:
12 inches high, horizontal circle 5.25 inches diameter; vertical circle 3.75 inches diameter; telescope 12 inches long; needle 2.25 inches

Discussion:

This instrument was made after 1855 when Marc François Secretan went into business on his own, and before 1901 when the Smithsonian purchased it from Anthony J. Gies, Commissioner of Streets and Drainage in Manila, for use in the Pan American Exhibition. It is similar to the instrument that Secretan called a repeating theodolite. The horizontal circle is silvered, graduated to 10 minutes, and read by four verniers and two magnifiers to 20 seconds; the vertical circle is silvered, graduated to 15 minutes, and read by two double verniers to 30 seconds.

Ref:

L'Industrie Française des Instruments de Précision, Catalogue (Paris, 1901-1902), pp. 247-252.

Further Information:

Theodolite
Secretan

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