Lawrence Engineering Service 10-B Mannheim Simplex Slide Rule

Lawrence Engineering Service 10-B Mannheim Simplex Slide Rule

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This inexpensive 9-1/2 inch one-sided wooden slide rule is painted white on the front face. A, D, and K scales are on the base, and B, CI, and C scales are on one side of the slide. A plastic indicator is in a metal frame. The top of the base is marked: MADE IN U.S.A. It is also marked LAWRENCE ENGINEERING SERVICE, PERU, INDIANA and PAT. PEND. The right end of the slide is marked: 10-B. Tables for equivalents and conversions appear on the back of the instrument, which is in a cardboard box covered with black synthetic leather.
George Lee Lawrence (1901–1976) established a firm in Chicago to make slide rules for photography. In 1935 he moved to Wabash, Ind., renamed the company Lawrence Engineering Service, and began to manufacture general purpose slide rules. In 1938 he relocated once more to Peru, Ind., probably to enlarge the factory. Lawrence's second wife, Vivian Breyer, received the company in their 1947 divorce. Its name was changed to Engineering Instruments, Inc., and the company remained in business until its building burned down in 1967. Thus, this rule dates between 1938 and 1947. The model 10-B sold for 25 cents during this period. There is no record that Lawrence ever received a patent for any aspect of his design or manufacturing process. According to the donor, this rule belonged to her father, George L. Sterns. Compare to 1980.0097.02.
References: Bruce Babcock, "Lawrence Engineering Service — A Tale from an American Small Town," Journal of the Oughtred Society 5, no. 2 (1996): 55–61; David G. Rance, "The Unique Lawrence," Proceedings of the 17th International Meeting of Slide Rule Collectors (September 2011), 87–107,; Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 195–196; accession file.
Currently not on view
Object Name
slide rule
date made
Lawrence Engineering Service
place made
United States: Indiana, Peru
Physical Description
wood (overall material)
plastic (cursor material)
metal (part material)
cardboard (case material)
overall: 3.5 cm x 26.5 cm x 3.5 cm; 1 3/8 in x 10 7/16 in x 1 3/8 in
ID Number
accession number
catalog number
Credit Line
Gift of Mabel Sterns
Rule, Calculating
General Calculation
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History
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Dear Sir/Madam, I recently acquired my '10-B' from a goodwill store in Queensland Australia where I reside. I'm a little 'gobsmacked' about the apparent age of this instrument: roughly the same age as my parents (!). On this instrument the 'table of equivalents & conversions' was replaced by a smaller table of 'scales appropriate to functions' and a reminder that commonsense should be used in determining the position of the decimal point with respect to the result.. The cursor appears to be clear celluloid (?) framed by nickel-plated brass. There is no obvious warping of the wood in any plane and the scales are in exquisite condition. The box it travelled in is in 'good nick' and was open at the top. Was there ever a cap? Presumably so... I had hoped to find an engineer's slide rule circa late 1960's and found this instead. A little like searching for a rifle and finding a musket haha. Sobering to think that this humble piece of Buxus has survived where countless artifacts haven't, and indeed where countless humans have shuffled 'on stage', delivered their lines and shuffled off 'stage left'. A moment's silence on that thought. I fully intend to master the use of my 'new' EMP-proof computational instrument. Another three decades of occasional use isn't out of the question. This would take it up to it's centenary... In numero veritas,

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