who invented slide rule and in what year
Slide rule The slide rule was invented around 1620â€“1630, shortly after John Napier's publication of the concept of the logarithm. In 1620 Edmund Gunter of Oxford developed a calculating device with a single logarithmic scale; with additional measuring tools it could be used to multiply and divide.[17] In c. 1622, William Oughtred of Cambridge combined two handheld Gunter rules to make a device that is recognizably the modern slide rule.[18] Like his contemporary at Cambridge, Isaac Newton, Oughtred taught his ideas privately to his students. Also like Newton, he became involved in a vitriolic controversy over priority, with his one-time student Richard Delamain and the prior claims of Wingate. Oughtred's ideas were only made public in publications of his student William Forster in 1632 and 1653.
Timeline of United States inventions (1890–1945) A Ferris wheel is a non-building structure, consisting of an upright wheel with passenger gondolas attached to the rim. Opened on June 21, 1893 at the Chicago World's Fair, the original Ferris Wheel was invented two years earlier by the Pittsburgh, Pennsylvania bridge-builder George Washington Gale Ferris Jr. in 1891.[19]