Desilva Octant

This octant has an ebony frame, reinforced brass index arm, and ivory name plate. The ivory scale is graduated every 20 minutes from -3° to +109°, and read by vernier with tangent screw to single minutes of arc. The inscription reads "W. DESILVA* LIVERPOOL."
The Smithsonian purchased this piece in 1903. At that time, it had a wooden box with a trade label that read "William Desilva, 78 Regent Road opposite the Bramley-Moore Hotel, Liverpool." Desilva was in business from 1851 to 1881, offering optical and nautical instruments.
Currently not on view
Object Name
date made
mid 19th century
Desilva, William
Physical Description
ebony (frame material)
ivory (inlay material)
brass (overall material)
glass (overall material)
radius: 9 5/8 in; 24.4475 cm
overall: 12 in x 9 3/4 in x 3 3/8 in; 30.48 cm x 24.765 cm x 8.5725 cm
place made
United Kingdom: England, Liverpool, Liverpool
ID Number
catalog number
accession number
Measuring & Mapping
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History, Kenneth E. Behring Center
Additional Media

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