Engineering Instruments 250-V Simplex Slide Rule
date: label: date made
content: ca 1958-1967
name: label: maker
content: Engineering Instruments, Inc.
label: maker
content: Lawrence Engineering Service
notes: label: Description
content: This ten-inch, one-sided wooden slide rule is coated with white plastic on the front face and both sides of the slide. A, D, and K scales are on the base. B, CI, and C scales are on one side of the slide, with S, L, and T scales on the other side. The indicator is clear frameless plastic. The top of the base is marked: MADE IN U.S.A. It is also marked: ENGINEERING INSTRUMENTS, INC., PERU, INDIANA. It is also marked: PAT. PEND. The right end of the slide is marked: 250-V. Tables for equivalents and conversions appear on the back of the instrument. The rule fits in a tan paper sleeve—neither the original simulated leather case nor the instruction manual were received with the instrument.
label: Description
content: Vivian (Breyer) Lawrence received Lawrence Engineering Service, a manufacturer of slide rules in Peru, Ind., in her divorce from George Lee Lawrence in 1947. Her new husband, Frank Bozarth, was president of the renamed Engineering Instruments, Inc., until the company burned down in 1967. Although the building was insured, Engineering Instruments never rebuilt. This rule probably dates between the late 1950s and 1967. The model number may mean that the rule is 250 mm long with a veneered finish, although the scales are actually about 255 mm. The rule sold for $2.00. Compare to 1983.0042.01.
label: Description
content: References: Bruce Babcock, "Lawrence Engineering Service — A Tale from an American Small Town," <i>Journal of the Oughtred Society</i> 5, no. 2 (1996): 55–61; David G. Rance, "The Unique Lawrence," <i>Proceedings of the 17th International Meeting of Slide Rule Collectors</i> (September 2011), 87–107, http://www.sliderules.nl/index.php?p=papers; Peter M. Hopp, <i>Slide Rules: Their History, Models, and Makers</i> (Mendham, N.J.: Astragal Press, 1999), 195–196.
label: Location
content: Currently not on view
place: label: place made
content: United States: Indiana, Peru
topic: label: Subject
content: Mathematics
label: Subject
content: Rule, Calculating
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
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content: Slide Rules
creditLine: label: Credit Line
content: Gift of Terry M. Sachs
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1980.0097.02
label: accession number
content: 1980.0097
label: catalog number
content: 1980.0097.02
objectType: label: Object Name
content: slide rule
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: plastic (laminate and cursor material)
label: Physical Description
content: paper (case material)
label: Measurements
content: overall: .9 cm x 28.9 cm x 5.9 cm; 11/32 in x 11 3/8 in x 2 5/16 in