The slide rule was invented by English mathematician William Oughtred (1575-1660) in the mid seventeenth century on the basis of innovations by John Napier (the inventor of logarithms) and Edmund Gunter (the creator of logarithmic scales). The slide rule is a mechanical analog computing tool used to do multiplication, division, roots, logarithms, and trigonometry calculations. Although slide rules were used in the U.S. starting in the eighteenth century, it was not until Keuffel and Esser began selling imported slide rules based on an 1859 design by French artillery officer Amédée Mannheim that the device became popular in America.
Manual: The Mannheim Slide Rule; Complete Manual with Tables of Settings, Equivalents & Gauge Points. By William Cox, K&E, c. 1909-13, p. i.