Casella Pocket Altazimuth

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Description: The Pocket Altazimuth combines a sighting telescope with a magnetic compass for determining bearings, and a pendulum (or wheel) clinometer for determining vertical inclinations. Small, compact, and accurate, it was said to be especially useful for travelers and military surveys.; L. Casella introduced the form in 1864, noting that is was "improved and modified by the kind assistance of Francis Galton, F.R.S." The reference is to Francis Galton, (1822-1911), a gentleman scientist who was a Fellow of the Royal Society of London, and whose work ranged over a number of fields.; This example is signed "L. Casella Maker to the Admiralty & Ordnance LONDON 166." The U. S. Geological Survey transferred it to the Smithsonian in 1907.; Ref: L. P. Casella, An Illustrated and Descriptive Catalogue of Surveying, Philosophical, Mathematical, Optical, Photographic, and Standard Meteorological Instruments (London, [about 1871]), p. 71.; Karl Pearson, (Cambridge, 1914-1930), vol. 2, p. 50.
Location: Currently not on view

Measurements: overall: 3 in x 5 1/2 in x 1 1/4 in; 7.62 cm x 13.97 cm x 3.175 cm; overall: 2 7/8 in x 1 1/4 in x 5 1/2 in; 7.3025 cm x 3.175 cm x 13.97 cm

See more items in: Medicine and Science: Physical Sciences; Measuring & Mapping; Surveying and Geodesy

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