THE EARTH AS A PLANET 361 



place where the journey began there has been recorded 

 twenty-four hours or a whole day more of time than has been 

 counted by the traveler with his repeated "setting back" 

 of his time-piece. He is a day behind the calendar upon his 

 return. While his watch reading is in accord with the time 

 at the starting place, his day of the week is made right only 

 by passing over one day in the calendar. If his return is on 

 Tuesday evening by his reckoning, then he must consider 

 the next day Thursday. As a matter of custom this jumping 

 over one of the days of the calendar is done by west bound 

 travelers when crossing the Pacific Ocean, and when near 

 the so-called international date line. 



To travel eastward involves a similar series of changes 

 and adjustment of days. But in this case the watch must 

 be set ahead an hour at a time, and at the international date 

 line two days in succession have the same name. There 

 has been a day gained by the traveler, and his calendar is a 

 day ahead of the places to which he comes, making it neces- 

 sary to live one of his days over again so far as the name of 

 the day is concerned. 



Each new day upon earth may be considered as having its 

 beginning at this international date line, and as traveling 

 around the earth westward. When this same day is just be- 

 ginning at places on that side of the date line to reach which 

 the day "has traveled around the earth," it is twenty-four 

 hours old on the beginning side of the line. The whole earth 

 will then be covered by the same calendar day. But at that 

 very instant the next succeeding day is beginning on the 

 "east side" of this imaginary line to pass on in turn around 

 the earth, while the preceding day is growing older and 

 finally is to pass off from earth when the new day in turn 

 comes to the "west side" of the date line. 



It is not so strange as at first it may appear that news- 

 papers, with headlines that tell of startling events in Europe 



