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A variety of rulers A carpenter's rule Retractable flexible rule or tape measure A closeup of a steel ruler A ruler in combination with a letter scale. A ruler, sometimes called a rule, scale or a line gauge or metre/meter stick, is an instrument used to make length measurements, whereby a length is read from a series of markings called "rules" along an edge of the device. [1]
In 1851 Anton Ullrich invented the folding ruler, and in 1887 obtained the patent for the springed hinge of the folding ruler. The "Gebrüder Ullrich" company expanded quickly and later built another factory site in the neighbouring village of Kirrweiler.
The duplex rule was invented by William Cox in 1891 and was produced by Keuffel and Esser Co. of New York. [ 17 ] [ 18 ] In 1881, the American inventor Edwin Thacher introduced his cylindrical rule, which had a much longer scale than standard linear rules and thus could calculate to higher precision, about four to five significant digits.
Ruler A tape measure or measuring tape is a long, flexible ruler used to measure length or distance . [ 1 ] It usually consists of a ribbon of cloth, plastic, fibreglass, or metal strip with linear measurement markings.
William Oughtred (5 March 1574 – 30 June 1660), [1] also Owtred, Uhtred, etc., was an English mathematician and Anglican clergyman. [2] [3] [4] After John Napier discovered logarithms and Edmund Gunter created the logarithmic scales (lines, or rules) upon which slide rules are based, Oughtred was the first to use two such scales sliding by one another to perform direct multiplication and ...
This is a list of rulers of Kievan Rus', the Tsardom of Russia, the Russian Empire, the Russian Republic, the Soviet Union, and the modern Russian Federation.It does not include regents, acting rulers, rulers of the separatist states in the territory of Russia, persons who applied for the post of ruler, but did not become one, rebel leaders who did not control the capital, and the nominal ...
The Fell All-Way precision level, one of the first successful American made bull's eye levels for machine tool use, was invented by William B. Fell of Rockford, Illinois in 1939. [2] The device was unique in that it could be placed on a machine bed and show tilt on the x-y axes simultaneously, eliminating the need to rotate the level 90 degrees.
Robert Gair was a Scottish printer and paper bag maker who invented the folding carton in 1879. [1] Born in Edinburgh, Scotland in 1839, he emigrated to the United States at age 14. Gair invented the paperboard folding carton by accident when a metal ruler