Casella Telescope

Description
Casella described this as a "Military or Target Telescope" that "will show the time by a clock at six miles distance, and the form of the rocks of Calais from Dover, a distance of twenty-one miles." It has an achromatic objective, and a tapered four-draw brass body covered with leather. Its four-element erecting eye piece is "pancratic," which means that it can produce various magnifications (in this case, of 20, 25, or 30 times). It was probably made after 1878 when the U.S. Coast Survey became the U.S. Coast & Geodetic Survey. It was transferred to the Smithsonian in 1929. The instrument bears the inscription "L. CASELLA LONDON" and "U.S.C.&G.S. No. 168."
Louis Paschal Casella (1812–1897) was an Italian immigrant who opened a shop in London in 1848, offering a wide range of meteorological, mathematical, optical, and philosophical instruments, and photographic apparatus. Casella prospered, and soon obtained appointments to the Prince of Wales and several government agencies. With Charles Frederick Casella in charge, the firm became C.F. Casella in 1897, and C. F. Casella & Company Ltd. in 1910.
Ref: L. Casella, List with Notes of Standard Meteorological and Other Instruments for Observatories, Travellers and Explorers, and the Army and Navy (London, 187?), p. 61.
Gloria Clifton, Directory of British Scientific Instrument Makers 1550-1851 (London, 1995), pp. 51-52.
Location
Currently not on view
Object Name
telescope (spy glass)
telescope
maker
Casella, Louis Paschal
Measurements
overall: 12 7/8 in x 2 5/16 in; 32.7025 cm x 5.842 cm
place made
United Kingdom: England, London
ID Number
PH*309649
catalog number
309649
accession number
106954
subject
Measuring & Mapping
Navigation
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Medicine and Science: Physical Sciences
Navigation
Data Source
National Museum of American History, Kenneth E. Behring Center

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