448 Transactions. — Chemistry and Physics. 



should be that of Greenwich"; also that "longitude should 

 always be counted from this meridian in both directions up 

 to 180°, east longitude being plus and west longitude 

 minus " ; and finally, that " the astronomical day should 

 begin at mean midnight." 



There were therefore three distinct proposals before the 

 Conference — (1) " The change of the astronomical day [the 

 astronomical day at present begins at midday, not at mid- 

 night] ; (2) the use of a universal day ; (3) the reckoning of 

 the hours from to 24 instead of in two periods of twelve 

 each."* 



The first of these proposals has not been adopted gene- 

 rally, as it has been felt that it would involve too much 

 trouble and expense in the rearrangement of astronomical 

 ephemerides. The only work of the sort in which the sug- 

 gestion has so far been acted on is the " Annuaire " of the 

 Paris Bureau des Longitudes, which made the change in the 

 ephemeris for 1900. f 



The second proposal (that for a universal day) has been 

 found to be in advance of public opinion, and it has therefore 

 been adopted merely in the modified form of standard times 

 governed by hour meridians, J the minutes and seconds being 

 everywhere the same as at Greenwich (except, as already 

 explained, in the cases of those countries which have compro- 

 mised by taking the odd half-hour). The proposal to accept 

 Greenwich as the initial meridian did not at first find favour 

 with some nations, and it was suggested that the meridian 

 either of Jerusalem or of some obscure island or other not 

 belonging to any great power should be chosen instead. 

 Ultimately, however, it was recognised that the meridian of 

 Greenwich was in every way the most suitable, and those 

 nations which have taken up the reformed system have been 

 content to set their clocks on the basis of the Greenwich 

 reckoning. 



The third idea (that of having a twenty-four-hour dial) 

 has been realised on part of the Canadian Pacific Eailway 

 and on some other railways in America, and it has also been 

 given effect to in Italy, in Switzerland ('?), in Belgium, and in 

 Spain. Many people claim (and with apparent reason) that a 

 great simplification of railway time-tables is effected when the 

 letters " a.m." and " p.m." are got rid of. 



The following is a list of the countries which have adopted 



* " The Observatory " for February, 1901. 

 t Ibid. 



J The basis of the system being that for 7£° of longitude on either side 

 of a central meridian one time only shall be kept. 



