Tavernier-Gravet Mannheim Simplex Slide Rule

This eight-inch wooden Mannheim linear slide rule is coated with white celluloid and has a brass indicator in the single chisel style. It has no endpieces. The top edge is beveled and has a scale of 20 centimeters, divided to millimeters. A 20-centimeter scale, divided to millimeters, is on the front edge. A third 20-centimeter scale under the slide is numbered from 22 to 41.

The top of the base has a scale divided logarithmically from 1 to 10 twice. The bottom of the base has a scale divided logarithmically from 1 to 10. These are the usual A and D scales, although they are not lettered. One side of the slide has the same two scales (the usual B and C scales, although they are not lettered). The other side of the slide has a scale of tangents that runs from 0 to 45 degrees and is lettered T; a scale of equal parts that runs from 0 to 10 and divides every two centimeters into 50 increments; and a scale of sines that runs from 70 to 0 and is lettered S. Compare to MA.318474. There is a place on the back of the instrument for a table of physical constants, but there is no table.

The top of the base is marked: TAVERNIER-GRAVET. The bottom of the base is marked: RUE MAYET 19.PARIS. It is also marked there: KEUFFEL & ESSER Co NEW-YORK & CHICAGO. The back is marked: MÉDAILLES D'OR 1878 ET 1889.

The British engineer's rule was brought to France by Edme-François Jomard in 1815, and by around 1820 Paul-Etienne Lenoir was manufacturing them in Paris. Lenoir's firm was succeeded by Gravet-Lenoir and later Tavernier-Gravet. From about 1851, Tavernier-Gravet manufactured a slide rule on the design of Amédéé Mannheim; this is such a slide rule. It was made after Tavernier-Gravet was awarded gold medals at world's fairs held in Paris in 1878 and 1889.

Before Keuffel & Esser manufactured its own rules around the turn of the 20th century, the company sold slide rules from Tavernier-Gravet and from Dennert & Pape of Germany. (Additional company history is provided with MA.318477, MA.318478, and MA.326613.) Although the scales and indicator resemble the ten-inch model 479–2 (subsequently numbered 1746N and 1746), a rule of this length (scales about 8" long) is not listed in K&E catalogs. The ten-inch version with brass indicator cost $4.50 between 1883 and 1890. In 1892 the single-chisel indicator was replaced with a double-chisel indicator.

References: Florian Cajori, A History of the Logarithmic Slide Rule and Allied Instruments (New York: Engineering News Publishing Company, 1909), 55–58, 80–81; M. Jomard, "The Slide Rule in France—1815," trans. Francis Wells, Journal of the Oughtred Society 8, no. 2 (1999): 11–16; Catalogue of Keuffel & Esser, 17th ed. (New York, 1883), 93; Catalogue of Keuffel & Esser, 20th ed. (New York, 1887), 129; Catalogue of Keuffel & Esser, (New York, 1890), 131.

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