350 MISCELLANEOUS PAPERS. 



numbered from zero in the direction contrary to the motion of. the earth 

 or towards the right, and in imaf^inatioii the numbers be placed in a 

 conspicuous manner against the sky, the spectator ^Yill have within his 

 range of vision a great dial-plate ou which as it revolves the vertical 

 sun will continually point to the passing hours. With the twenty-four 

 division points so numbered around the circle of the horizon, it is obvi- 

 ous that every hour in the day, and equally the smaller divisions of 

 time, will invariably be manifested by the solar i)assage. 



As the imaginary point of observation, the north pole, is common to 

 every meridian, the hours and minutes indicated by the great polar 

 chronometer will be equally common to every locality on the surface of 

 the globe. Whatever the longitude, the solar passage will be the index 

 of time. Two successive passages at zero will complete an interval of 

 tw^enty-four hours ; but it will not be a day in the ordinary sense, as an 

 ordinary day is a local phenomenon in no two longitudes idieutical.* To 

 distinguish this new interval of time common to the whole world from 

 the infinite number of local daj^s at present recognized it has been sug- 

 gested to term it the " Cosmic Day," or some distinctive appellation by 

 which it niaj^ be known. 



Necessarily the zero point must be arbitrarily selected according to 

 convenience, and any zero whatever, other things being equal, would 

 serve the purpose which we have in view. We have only to assume the 

 zero so selected to coincide with the Autiprime Meridian determined by 

 the Washington Conference, and the Cosmic Day will be identical witii 

 the Universal Day, established under the same authority. A Universal 

 or Cosmic Day may therefore be defined as the interval of time between 

 two succeeding solar passages at the Antiprime Meridian common to all 

 nations. 



In his recent discourse on the sul)ject at the Eoyal Institution, Lon- 

 don, the astronomer royal for Great Britain, Mr. Christie, expressed a 

 preference for the term "World Time" to designate this new measure of 

 duration. It has been termed " Cosmic Time" by various societies and 

 individuals ; but the name is of secondary importance, if it be under- 

 stood that the new measure of time is equally related to every locality. 

 By its very nature. Cosmic Time, or by whatever name it may be known, 

 must coincide with some one of the multiplicity of existing times. The 

 decision of the Washington Conference caused it to correspond with 

 CJreenwich Civil Time. Greenwich time is the local time of Greenwich. 

 Cosmic Time is a new and an entirely different conception; it is the time 

 of the world common to every nation. "Cosmic" and "Greenwich" time 

 are identical fortuitously, but the expressions imply two totally differ- 

 ent ideas, and a proper deference to national sensitiveness suggests the 

 good taste and expediency of distinguishing the two ideas by dift'erent 

 terms. Some distinctive name is undoubtedly called for, until the 



* The Nautical Almanac defines an ordinary solar day to be the interval of time be- 

 tween the departure o{ any meridian from the sun and its succeedin}? returu to it. 



