A. S. Aloe Pocket Compass (prismatic)

Like the prismatic compass for which Charles Schmalcalder obtained a British patent in 1812, this one lets the user read the card while sighting a distant object. It has a tall folding sight at north, and at south, a shorter sight with a prismatic eyepiece at its base. The floating card is colored bright green; the numbers around its edge read correctly when seen through the prismatic eyepiece. Unlike the Schmalcalder instrument, this one has a solid plate covering most of the card. It was termed an Improved Hutchinson Prismatic Compass, said to be lighter and less bulky "than the old form," and was "adopted by the various branches of the English and Foreign Services." This example, which belonged to the University of Missouri at Columbia, is marked "A. S. ALOE CO. ST. LOUIS." A. S. Aloe & Company became A. S. Aloe Co. in 1894.
Ref: James J. Hicks, Illustrated & Descriptive Catalogue (London, 1876), p. 141.
Currently not on view
Object Name
compass (pocket prismatic)
A.S. Aloe and Company
place made
United States: Missouri, St. Louis
ID Number
catalog number
accession number
Measuring & Mapping
Surveying and Geodesy
See more items in
Medicine and Science: Physical Sciences
Surveying and Geodesy
Data Source
National Museum of American History, Kenneth E. Behring Center
Hicks, James J.. Illustrated & Descriptive Catalogue
Additional Media

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