Spherometer
date: label: date made
content: ca 1800s
name: label: maker
content: Alvan Clark & Sons
notes: label: Description
content: A spherometer is used primarily to measure the curvature of objects such as lenses and curved mirrors. This example came from the U.S. Naval Observatory. It was made by Alvan Clark & Sons for the U.S. expeditions to observe the 1874 transit of Venus. It has only a horizontal scale and no vertical scale common to most spherometers. The box for this sphereometer appears to be homemade.
label: Description
content: Alvan Clark (1804-1887) was the first prominent American telescope maker. In 1846 he went into business with his two sons, Alvan G. and George B. Clark, founding Clark & Sons. At first they repaired scientific instruments, but the firm quickly progressed on to making telescopes. During the second half of the 19th century, five of Clarks' telescopes held the record for world's largest. To aid in grinding lenses, Clark & Sons also made devices such as spherometers.
label: Description
content: Ref: Warner, D. J., "Alvan Clark & Sons: Artists in Optics," <i>United States National Museum Bulletin </i> 274 (1968): 1-13.
label: Location
content: Currently not on view
place: label: place made
content: United States: Massachusetts, Cambridgeport
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
content: Science & Mathematics
label: See more items in
content: Spherometers
creditLine: label: Credit Line
content: U.S. Naval Observatory
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 2005.0172.07
label: accession number
content: 2005.0172
label: catalog number
content: 2005.0172.07
objectType: label: Object Name
content: spherometer
physicalDescription: label: Physical Description
content: metal (instrument material)
label: Physical Description
content: wood (box material)
label: Measurements
content: overall: 4 in x 3 1/4 in x 4 in; 10.16 cm x 8.255 cm x 10.16 cm
label: Measurements
content: overall: 4 in x 3 1/4 in x 4 1/8 in; 10.16 cm x 8.255 cm x 10.4775 cm