414 



SCIENCE. 



[Vol. IV., No. 91. 



THE WORK OF THE MERIDIAN 

 CONFERENCE. 



Though entangled and loaded down with the 

 cumbersome and roundabout methods of diplo- 

 macy, and unnecessarily surrounded with the 

 secrecy of our State department, the Meridian 

 conference has yet reached, in the main, very 

 sensible conclusions ; much the same, no doubt, 

 as a body composed entirety of the leading 

 representatives of the scientific and business 

 interests involved would have reached in one- 

 fourth the time, with much greater unanimity, 

 and without stirring up the feelings and jeal- 

 ousies which the semi-political character of the 

 bodj r has engendered, and which will make its 

 conclusions of much less weight, since a con- 

 siderable percentage of the delegates will de- 

 cline to recommend them to their respective 

 governments. But with England, the United 

 States, and the principal European powers, 

 France excepted, in accord, the action of the 

 rest will be of less importance, however desir- 

 able unanimit}' would have been. 



It was almost a foregone conclusion, that 

 Greenwich would be selected as the prime 

 meridian, on account of the overwhelming sci- 

 entific and commercial reasons in its favor ; 

 while the proposition for an entirely new neu- 

 tral meridian, with its necessary confusion and 

 needless expense, merely for sentimental rea- 

 sons, was too absurd to deserve serious con- 

 sideration. 



The conclusion to reckon longitudes east 

 and west to plus and minus 180° is, no doubt, 

 all things considered, the best. Considered 

 simply as a method of putting down longitudes 

 on charts, the continuous reckoning from 0° 

 to 360° is, without question, less liable to mis- 

 take, simpler, and mathematically more ele- 

 gant. But longitude is inseparably connected 

 with local time, and herein arises the follow- 

 ing difficulty. So long as the sun shines, and 

 the earth revolves on its axis, the mean solar 

 daj', with its alternating light and darkness, 

 must be the great natural unit of time-reckon- 

 ing. Moreover, for civil purposes the date 

 must change during the hours of sleep ; and 

 hence the civil ' day ' must begin in the night, 



and should, for convenience, begin within an 

 hour at least of midnight. Therefore civil 

 dates and hours must be approximately local 

 ones; i.e., must differ with the continuous 

 westward sweep of the sun, the eastern times 

 being farther ahead. A necessary consequence 

 is, that on some meridian of the globe, where 

 the east meets the west, the local time must 

 jump one day ; so that the people living on 

 the west side of this line, i.e., in the ' far east,' 

 will be one day ahead of their neighbors on 

 the east side ; and there is no way of avoiding 

 this inconvenient arrangement. There is thus 

 an inseparable connection between universal 

 or absolute time, local time, and longitude ; 

 and the connection will be most simply ex- 

 pressed, and most easily comprehended, if the 

 longitudes jump 360° at the same point on the 

 earth where the local time jumps twenty-four 

 hours. 



The recommendations of the conference, that 

 the prime meridian be that of Greenwich, that 

 the universal day be the civil day (beginning 

 at midnight) of the prime meridian, and that 

 longitudes be reckoned to plus and minus 180° 

 east and west respectively from this meridian, 

 accomplish their object with the least change 

 from the existing status, the day and the lon- 

 gitudes changing in the Pacific at 180° from 

 Greenwich. 



For the few islands lying close to, or on 

 both sides of, the 180th meridian, like the Fee- 

 jees, which are bound to keep up intercourse 

 with each other, it will be most convenient to 

 have the same day; and this will fall in with 

 the adopted plans, if the longitudes are all 

 given with the same sign, and extended a little 

 beyond 180°, to include the group. 



The recommendation to count the universal 

 day from zero to twentj^-four hours might well 

 have been extended to the local times as well, 

 though not so essential in this case. Still, the 

 more international intercourse and cable news 

 bring out the differences between local times and 

 their relation to absolute time, the more inade- 

 quate and unsatisfactory seems the clumsj^ a.m. 

 and p.m. division of the day into two parts. 

 Railroads can do something towards doing 





