1886.] on Universal Time. 389 



take account of tlie effect of business intercourse between different 

 communities separated by distances which may range from a few miles 

 to half the circumference of our globe. So long as the means of 

 communication were slow, the motion of the traveller was insignificant 

 compared wath 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 600 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 traveller due to the combined motions would be 660 miles an 

 hour, whilst if the train were going westward it would be only 540 

 miles. In other words, if local time be kept at the stations, the 

 apparent time occupied in travelling sixty miles eastward would be 

 54 minutes, whilst in going sixty miles westward it would be 66 

 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 botb 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 travelled east or west. This would seem to be 

 the reductio ad ahsurdum 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. Green- 

 wich) 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 20 minutes behind Greenwich time, the discord- 

 ance between the sun and the railway clock was of no practical con- 

 sequence. 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, &c., 

 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 36^ minutes. 



But in countries of great extent in longitude, such as the United 



