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
Object Name
date made
ca 1877
Colton, Allen L.
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
place made
United States: Michigan, Ann Arbor
ID Number
accession number
catalog number
Science & Mathematics
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Martha Taylor
Additional Media

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Selected comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about the history, rarity, or value of your personal artifacts.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Enter the characters shown in the image.