Slide RulesCylindrical Slide Rules
Writing a logarithmic scale in a spiral that is then imprinted around the outside of a cylinder allows instrument makers to lengthen the scale. Since a logarithmic scale only needs to run to 10 twice to include all possible results from adding or subtracting two logarithmic numbers, this means that the distance between the points on the scale may be increased. When any two numbers on the scale are further apart, the user may read a fractional position between these numbers (expressed as a decimal) to a finer level of granularity. For example, on a 10" linear slide rule, results generally may be calculated to only three significant figures (0.123, 1.23, 12.3, 123, 1230, and so on). A cylindrical slide rule may provide results of up to seven significant digits (0.1234567, 1.234567, 12.34567, 123.4567, 1234.567, and so on).
On the other hand, cylindrical slide rules were typically about twice as expensive to produce as linear slide rules, and the provenances for the objects on this page indeed suggest that, in the main, only corporate and government offices could afford them. A number of the objects in this category were received with instruction manuals and advertising pamphlets, which may be viewed in the Index by Makers & Retailers. The collection includes multiple examples for several of the objects, as the 23 items below represent only eight different slide rules, half developed in Europe and half invented by Americans. The cylindrical slide rule by Edwin Thacher, a Pennsylvania railroad bridge designer, also illustrates the 19th-century shift in production from Europe to the United States, as originally William Ford Stanley's London firm made the entire instrument. Then, Keuffel and Esser of New York City began constructing the wooden drum and brass and wood stand while continuing to import the scales printed on paper and pasted around the drum. Finally, K&E developed its own dividing engine for printing the scales and henceforth manufactured the entire instrument in the United States.
"Slide Rules - Cylindrical Slide Rules" showing 1 items.
- This is the U.S. patent model for a cylindrical slide rule invented by George Fuller (1829–1907), a British civil engineer and professor of engineering at Queen's College, Belfast. Fuller received patents in Great Britain (no. 1044) in 1878 and in the United States in 1879. W. F. Stanley of London manufactured the rule from 1879 until 1975, and it was marketed in the United States by Keuffel & Esser, Dietzgen, and other dealers.
- The model has a wooden handle and shaft, with a wooden cylinder that slides up and down the shaft. A paper covered with scales fits around the cylinder. The lower edge of the cylinder has a scale of equal parts. The remainder bears a spiral scale divided logarithmically. A rectangular clear plastic pointer has broken from its attachment on the handle and is tucked into a red ribbon tied around the cylinder. A paper patent tag is marked: No. 291.246; 1879 (/) G. Fuller. (/) Calculators. (/) Patented Sept 2. (/) 1879. A printed description from the patent application of April 16, 1878, is glued to the back of the tag. The tag is attached to the handle with a red ribbon.
- L. Leland Locke, a New York mathematics teacher and historian of mathematics, collected this patent model and intended it for the Museums of the Peaceful Arts in New York City. When that institution encountered financial difficulties in 1940, Locke gave a collection of objects, including this model, to the Smithsonian Institution.
- For production models of this instrument, see MA*313751, MA*316575, and 1998.0046.01.
- References: George Fuller, "Improvement in Calculators" (U.S. Patent 219,246 issued September 2, 1879); The Report of the President of Queen's College, Belfast, for the Year Ending October, 1876 (Dublin, 1877), 9, 29–30, 107–110; James J. Fenton, "Fuller's Calculating Slide-Rule," Transactions and Proceedings of the Royal Society of Victoria 22 (1886): 57–61; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 42–43.
- Currently not on view
- date made
- Fuller, George
- Fuller, George
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- accession number
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- Data Source
- National Museum of American History, Kenneth E. Behring Center