tLUMSDEx] UNIFICATION OF Tl.ME 87 



ol'the reform, in 1901, is assured if Germany luke action similar to thai 

 of Great Britain and France, the countries which, with the United States, 

 publish the '-greater ephemerides." The promoters of this movement in 

 Canada -and elsewhere are, therefore, awaiting- with some interest the 

 reply that shall be sent to the British Government by that country. To 

 these promoters, however, time is becoming an important factor. As is 

 well known, astronomical ephemerides are prepared three years in advance, 

 iind as the issue for 1901 should be printed off in 1897, or 1898, at latest, 

 and as the computers must have an interval in which to make necessary 

 alterations and changes, there remains but a comparativel}" brief pei'iod 

 within which to carry on effectually the discussion of the proposal with.a 

 view to its universal adoption. The beginning of a new century makes 

 a,dmittedly the best time-point, for a departure of the kind suggested. The 

 year date 1901 is by far the best for the same purpose, because it can 

 easily be fixed in the minds of future astronomers and computers^whose 

 investigations may require an examination of past records. As a date, it 

 is certainly superior to those of the years in which the Gregoi'ian system 

 was substituted for the Jvilian, and when other changes took place of 

 which note has to be taken by scientific investigators. 



The question is not a new one, but cii'cumstances now exist which 

 give it a prominence it never before possessed. It is said that Hipparchus 

 " the father of Astronomy."' himself counted the hours from midnight to 

 midnight. The practice of taking noon as the moment from which the 

 hours were to be counted, originated with Ptolemy, not always a safe 

 guide but, who, in this instance adopted, possibly, the system best suited 

 to the means at his disposal. In 1804, La Place sent to Le Bureau des 

 Longitudes, a letter in which he proposed to unify asti-onomical time 

 with civil time, by counting the hours from midnight. After an ex- 

 haustive discussion, the Bureau, by a vote of T to 5, adopted the proposal. 

 Nevertheless, La Connaissance des Temps, which was and is published by 

 the Bureau, continued to appear in the ancient manner of counting 

 a.stronomical time. La Place, however, in La Jléchanique Céleste and 

 in the calculation of his Tables employed civil time and, in this, was 

 imitated by the other Fi-euch constructors of tables until Le Verrier 

 reverted to the former system of reckoning. In 1884, 1885 and 1886, the 

 question having again arisen as a result of the discussions which took 

 place at the conferences at Washington and Geneva, M. Faye, the French 

 astronomer, had his attention called more than once to the subject and 

 was reminded that, under the influence of Ija Place, the Bureau had 

 formerly calculated the Lunar and Planetary Tables for Paris mean mid- 

 night, but in view of the probable o^^position of the German astronomers, 

 indicated by their attitude at Geneva, no decision was reached. Now, as 

 we see, the Bureau has committed itself at a time when such an adhesion 

 to the principle involved, marks a great step in advance. In this con- 



