Scale RulesCalculating Rules
In addition to length measurements, scale rules could be marked with aids for calculation. Perhaps the most notable rule of this type was Gunter's scale, which was similar to a sector or a slide rule. Gunter's scales are named after Edmund Gunter, a 17th-century English mathematical practitioner who figured out how to put a table of logarithms on a rule so that logarithmic calculations could be made with the aid of dividers. These instruments were especially handy for mathematicians and navigators.
The mathematics collections contain several other objects, ranging from the 18th to the 20th centuries, that were used to simplify computations for tasks including designing sundials, keeping track of calendar dates, and plotting data for aeronautical engineering. A few of these rules were designed specifically for positioning artillery.
"Scale Rules - Calculating Rules" showing 1 items.
- Robert Frederick Roche (b. about 1839), an immigrant from Ireland, apparently purchased this 20-inch wooden rule as a blank straight edge and then marked it by hand. One side has a proportional scale marked up to one billion; an evenly divided scale numbered by ones from 1 to 12, with each unit equivalent to 4 cm; a logarithmic scale; a scale labeled PERCENTAGE; a scale labeled under 2 Percent; and a proportional scale numbered by ones from 2 to 13, with the number 6 miswritten as 8. The upper left corner of this side is missing. The right end is marked: Robert (/) F. Roche. A hole near the right end is for hanging the rule.
- The other side has a proportional scale of units that is numbered by ones from 2 to 17 and labeled TENS at the right end; a logarithmic scale of tenths that is labeled UNITS at the right end; a proportional scale of roots and powers numbered by ones from 2 to 14; a proportional scale numbered by ones from 11 to 0; a scale of equal parts numbered by ones from 1 to 12, with each unit equivalent to 4 cm; and a scale of equal parts numbered by ones up to 47, with each unit equivalent to 1cm. The left end is stamped with an eagle logo and the word: TRADEMARK. This end is also marked: KEUFFEL & ESSER (/) N.Y.
- Although the instrument was marked by Keuffel & Esser, by 1880 that firm sold no 20-inch straight edges. James W. Queen of Philadelphia did offer a 20-inch wooden straight edge for 30¢ in 1874, but one edge was beveled while both long edges of this instrument are straight. By 1877, like K&E, the shortest wooden straight edges offered by Queen were 24 inches long.
- In 1864, Roche served in the U.S. Army at Fort Columbus in New York Harbor. According to a patent he received in 1878 and a notice of his son, Roche was stationed at Fort Foote in Maryland from at least 1871 to 1878, when this installation that provided defense to Washington, D.C., was abandoned and Roche moved his family into the District of Columbia.
- References: James W. Queen & Co., Priced and Illustrated Catalogue . . . of Mathematical Instruments (Philadelphia, 1874), 46; James W. Queen & Co., Priced and Illustrated Catalogue . . . of Mathematical Instruments (Philadelphia, 1877), 46; Catalogue and Price List of Keuffel & Esser Co., 13th ed. (New York, 1880), 116; Robert F. Roche, "Improvement in Adding Sticks" (U.S. Patent 206,136 issued July 16, 1878); "New Inventions," Scientific American n.s., 39, no. 9 (August 31, 1878), 133; "Roche, Sidney," Who's Who in the Nation's Capital (Washington, D.C.: The Consolidated Publishing Company, 1921), 335. MA*311957 is an example of the patented device.
- Currently not on view
- date made
- ca 1880
- Keuffel & Esser Co.
- Roche, Robert F.
- ID Number
- accession number
- catalog number
- Data Source
- National Museum of American History, Kenneth E. Behring Center