Mott-Smith Gravimeter
date: label: date made
content: ca 1940
notes: label: Description
content: Gravimeters (gravity meters) are extremely precise instruments that measure the earth’s gravity at a specific location. Gravimeters are often used by prospectors to locate subterranean deposits of valuable natural resources (mainly petroleum) as well as by geodesists to study the shape of the earth and its gravitational field. Differences in topography, latitude, or elevation—as well as differences in subterranean density—all affect the force of gravity. Commonly, gravimeters are composed of a weight hanging on a zero-length spring inside a metal housing to negate the influence of temperature and wind. Gravity is then measured by how much the weight stretches the spring.
label: Description
content: Lewis Morton Mott-Smith (b. 1902), a professor of physics at Rice Institute in Houston, Texas, designed an astatic gravimeter that used an auxiliary quartz fiber as a labilizing spring. That meant that it could maintain a constant temperature within one-thousandth degrees centigrade under normal field conditions. Its basic features were covered by Mott-Smith's patent for a "torsion gravimeter" (#2,130,648), granted in 1938. A second patent (#2,304,191), granted in 1942, described a photoelectric indicating system for a gravimeter in which variations of intensity of the light source are eliminated by the use of a comparison light beam.
label: Description
content: The Mott-Smith Corporation was formed in 1935. By 1938 there were some 18 Mott-Smith gravimeters in use. This example was probably made in the early 1940s. Robert M. Iverson donated it to the Smithsonian in 1966.
label: Description
content: Ref: L. M. Mott-Smith, "Gravitational Surveying with the
label: Description
content: Gravity-Meter," <i>Geophysics</i> 2 (1937): 21-33.
label: Description
content: L. L. Nettleton, <i>Geophysical Prospecting for Oil</i> (New York: McGraw-Hill, 1940), pp 34-35.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Agriculture and Natural Resources
label: See more items in
content: Measuring & Mapping
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: AG.MHI-P-9195
label: catalog number
content: MHI-P-9195
label: accession number
content: 281132
objectType: label: Object Name
content: gravity meter, Atlas Model C
physicalDescription: label: Measurements
content: overall: 15 in x 14 3/16 in x 17 5/16 in; 38.1 cm x 36.068 cm x 43.942 cm