Of course, the same thing occurs on land. If we travel east our watches become too slow; if west, too fast; and the traveler is constantly occupied comparing his local time with those of the places he visits and of the trains on which he is carried. If in Pittsburgh, he finds western trains running by Columbus time, twelve minutes slower than Pittsburgh; eastern trains _via_ Pennsylvania Central R. R., nineteen minutes faster; and eastern trains on the Baltimore and Ohio road fourteen minutes faster—just four standards for one city. After some fourteen years of discussion among scientists and railroad men, an expedient has been finally adopted by which one clock will exhibit the “time” of the whole world. And it is simply this: Since by the earth’s revolution on its axis, any (all) point on the earth’s surface passes through 360° every twenty-four hours, or at the rate of 15° each hour, the surface can be divided into twenty-four sections, each 15° of arc, or one hour of time, in breadth, having for its standard time, the time of its (the section’s) middle meridian. This makes the difference in time between any two adjacent sections exactly one hour. Thus, if at Greenwich it is noon, from 7½° to 22½° west of Greenwich it is only 11:00 a. m., while in the section included by the meridians 7½° to 22½° east, it is 1:00 p. m. Or, when it is 3:25 p. m. at Greenwich, it is 2:25 and 4:25 p. m. respectively in the sections directly west and east of the Greenwich section; and 1:25 and 5:25 p. m. respectively in the next adjoining sections; and so on. Now applying this principle to our own country, we have the following scheme: ----------+-----------------+-------------------+------------------- | Local time | | Meridian | compared with | Boundaries of | Name of time. Standard.| Greenwich time. | Sections. | ----------+-----------------+-------------------+------------------- 60° W. | 4 hours slow. | 52½° to 67½° W. | Atlantic. 75° W. | 5 “ “ | 67½° to 82½° W. | Eastern. 90° W. | 6 “ “ | 82½° to 97½° W. | Valley or Central. 105° W. | 7 “ “ | 97½° to 112½° W. | Mountain. 120° W. | 8 “ “ | 112½° to 127½° W. | Pacific. From which it is readily seen we have but five instead of over fifty standards as heretofore; and that the time of any place can not vary more than thirty minutes from its own local time.