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Thacher's Cylindrical Slide Rule

Thacher's Cylindrical Slide Rule

Thacher's Cylindrical Slide Rule
Thacher's Cylindrical Slide Rule
Edwin Thacher (1839-1920), a U.S. engineer best known for his pioneering work in reinforced concrete construction, was the inventor of an ingenious cylindrical logarithmic slide rule, capable of giving accurate readings to four figures, which he patented in 1881. With this instrument, multiplication and division could be performed by the more simple operations of addition and subtraction to a much greater degree of accuracy than had been possible previously.