Page:Popular Science Monthly Volume 29.djvu/817

Rh compared with that due to the rotation of the earth, which gives us our measure of time. But it is otherwise now, as I will proceed to explain.

Owing to the rotation of the earth about its axis, the room in which we now are is moving eastward at the rate of about six hundred miles an hour. If we were in an express-train going eastward at a speed of sixty miles an hour (relatively to places on the earth's surface), the velocity of the traveler due to the combined motions would be six hundred and sixty miles an hour, while if the train were going westward it would be only five hundred and forty miles. In other words, if local time be kept at the stations, the apparent time occupied in traveling sixty miles eastward would be fifty-four minutes, while in going sixty miles westward it would be sixty-six minutes. Thus the journey from Paris to Berlin would apparently take an hour and a half longer than the return journey, supposing the speed of the train to be the same in both cases.

In Germany, under the influence of certain astronomers, the system of local time has been developed to the extent of placing posts along the railways to mark out each minute of difference of time from Berlin. Thus there is an alteration of one minute in time-reckoning for every ten miles eastward or westward, and, even with the low rate of speed of German trains, this can hardly be an unimportant quantity for the engine-drivers and guards, who would find that their watches appeared to lose or gain (by the station-clocks) one minute for every ten miles they have traveled east or west. This would seem to be the reductio ad absurdum of local time.

In this country the difficulty as to the time-reckoning to be used on railways was readily overcome by the adoption of Greenwich time throughout Great Britain. The railways carried London—i. e., Greenwich time all over the country, and thus local time was gradually displaced. The public soon found that it was important to have correct railway-time, and that even in the west of England, where local time is about twenty minutes behind Greenwich time, the discordance between the sun and the railway-clock was of no practical consequence. It is true that for some years both the local and the railway times were shown on village clocks by means of two minute-hands, but the complication of a dual system of reckoning time naturally produced inconvenience, and local time was gradually dropped. Similarly in France, Austria, Hungary, Italy, Sweden, etc., uniform time has been carried by the railways throughout each country. It is noteworthy that in Sweden the time of the meridian one hour east of Greenwich has been adopted as the standard, and that local time at the extreme east of Sweden differs from the standard by about thirty-six and a half minutes.

But in countries of great extent in longitude, such as the United States and Russia, the time-question was not so easily settled. It was