This instrument is marked "L. Casella, Maker to the Admiralty & Ordnance LONDON 5227" and "U.S.C.&G.S." It was made between 1878, when the U. S. Coast Survey became the U. S. Coast and Geodetic Survey, and the death of Louis Casella in 1897. Casella termed it a "Transit Theodolite . . . with achromatic telescope." New, it cost £24.
Ref: L. P. Casella, List of a Few Instruments in General Use, Selected from the General Catalogue of Standard Meteorological and Other Instruments for Observatories, Travelers and Explorers, and the Army and Navy (London, 1896), p. 26.
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