Colton Spherometer

A spherometer is a device used primarily for measuring the curvature of objects such as lenses and curved mirrors. For further information about spherometers, see object MA.315739.
This spherometer was constructed by Allen L. Colton (1857-1950) while he was a student at the University of Michigan. He worked for the US Weather Bureau in the late 1800s, followed by five years as assistant astronomer at the Lick Observatory where he was a physicist, photographer, and instrument maker. Early in the 20th century, he joined the faculty at the University of Wisconsin as a physics instructor. This item was donated to the Smithsonian in Colton's memory by his cousin.
To improve accuracy, a magnifying lever is mounted on the top of the micrometer disc. The two small arms would have pointed to a secondary scale that arched over the top of the device, but is now missing.
Barton, Albert (ed.), The Wisconsin Alumni Magazine 5, no. 3 (December 1903): 82.
Currently not on view
date made
ca 1877
Colton, Allen L.
place made
United States: Michigan, Ann Arbor
Physical Description
wood (overall material)
glass (overall material)
brass (overall material)
overall: 14.5 cm x 14.5 cm x 14.5 cm; 5 23/32 in x 5 23/32 in x 5 23/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Martha Taylor
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History


Add a comment about this object