Standard time.
Chiefly for the convenience of the railroads in the
United States a standard of time was established by mutual agreement in 1883, on principles first suggested by
Charles F. Dowd, of
Saratoga Springs, N. Y., by which trains are run and local time regulated.
The
United States, beginning at its extreme eastern limit and extending to the
Pacific coast, is divided into four time-sections: eastern, central, mountain, and Pacific.
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The eastern section, the time of which is that of the seventy-fifth meridian, lies between the
Atlantic Ocean and an irregular line drawn from
Detroit, Mich., to
Charleston, S. C. The central, the time of which is that of the ninetieth meridian, includes all between the last-named line and an irregular line from
Bismarck, N. D., to the mouth of the
Rio Grande.
The mountain, the time of which is that of the 105th meridian, includes all between the lastnamed line and the western boundary of
Montana,
Idaho,
Utah, and
Arizona.
The Pacific, the time of which is that of the 120th meridian, includes all between the last-named line and the
Pacific coast.
The difference in time between adjoining sections is one hour.
Thus, when it is twelve o'clock noon in New York City (eastern time, it is 11 A. M. (central time) at
Chicago, and 10 A. M. at
Denver (mountain time), and at
San Francisco, 9 A. M. (Pacific time). The true local time of any place is slower or faster than the standard time as the place is east or west of the time meridian; thus, the true local time at
Boston, Mass., is sixteen minutes faster than eastern standard time, while at
Buffalo, N. Y., it is sixteen minutes slower, the seventy-fifth
time meridian being half-way between
Boston and
Buffalo.
Local time and standard time agree at
Denver, Col., as
Denver is on the 105th meridian, that of the mountain section.
