Brearley, Harry Chase, 1870-1940, Ingersoll, Robt. H., & Bro · New York : Pub. by Doubleday, Page & Co. for Robert H. Ingersol & Bros. · leaf 110
ecame Pope Sylvester II, was the one who first tookthe important step of producing a real clock, and that thisoccurred near the close of the tenth century—or to bemore exact, about 990 A. D. This period was one of densestsuperstition, and expectancy of the end of the world was inthe air, since many… … Galileo Discovering the Principle of the Pendulum As a youth of seventeen Galileo watched a swinging lamp, in the Cathedral of Pisa, timed it by his pulse, and discovered the principle upon which pendulum clocks are built.
Time measurements · Clocks and watches
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