W. & S. Jones Reflecting Circle

Description
This reflecting circle belonged to Georgetown University in Washington, D.C. and may have been purchased when Georgetown built an astronomical observatory in the early 1840s. It is of the "English" form designed by Edward Troughton in 1796. Here the telescope, mirror, and filters are on one side of the circle, while the silver scale is on the other side. This scale is graduated to 20 minutes, and read by three verniers (one has a micrometer screw) to 20 seconds. The circle is supported on a heavy brass stand with a counterweight. The inscription reads "W. & S. Jones, 30 Holborn, London."
Ref: Abraham Rees, The Cyclopaedia; or, Universal Dictionary of Arts, Sciences, and Literature (London, 1819), vol. 8, art. "Circle," and Plate III of "Astronomical Instruments."
Location
Currently not on view
Object Name
reflecting circle
date made
ca 1845
maker
W. & S. Jones
Measurements
overall: 10 1/2 in; 26.67 cm
place made
United Kingdom: England, London
ID Number
PH*328403
catalog number
328403
accession number
272470
subject
Measuring & Mapping
Navigation
See more items in
Medicine and Science: Physical Sciences
Navigation
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Georgetown University
Additional Media

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