Standard time

Local mean solar time depends upon longitude; it is advanced by four minutes per degree eastward. In 1869 Charles F. Dowd, principal of a school in Saratoga Springs, N.Y., proposed the use of time zones, within which all localities would keep the same time. Others, including Sir Sandford Fleming, a Canadian civil engineer, strongly advocated this idea. Time zones were adopted by U.S. and Canadian railroads in 1883.

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