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LONGITUDE A'ND TIME-EEOKOE^IlSrG. 



A FEW WOEDS ON THE SELECTION OF A PRIME MERIDIAN TO BE COMMON 

 TO ALL NATIONS, IN CONNECTION WITH TIME-RECKONING. 



BY SANDFORD FLEMING, C.M.G., Etc. 



In another paper which I have submitted to the Institute, it has 

 been stated that the only means of obviating the confusion insepa- 

 rable from the present system of reckoning dates, is to measure time 

 by the absolute diurnal revolutions of the earth. 



By the system now followed, we count days by the consecutive 

 passage of the sun over the meridian of each spot on the earth's 

 surface. The number of spots around the globe may be said to be 

 infinite, and accordingly the duration of the day, as it is locally dis- 

 tinguished, considered in relation to absolute time, is marked by an 

 equally infinite variety. 



It has been argued that the earth should be considered as a whole, 

 and that its mean diurnal revolution should be the unit measui-e for 

 reckoning dates ; and this theory points to the consideration of the 

 necessity of establishing a common prime meridian. 



If we were placed in some neutral position, such as the earth's 

 tjentre, or its poles, and were called upon to determine the time 

 occupied by a diurnal revolution, we could fix on a point arbitrarily 

 chosen in a circle inscribing the earth's axis, and note the time 

 between two consecutive passages of the sun over that point. A 

 plane passing through that point and the poles, extended to the 

 surface of the globe, would establish a first or prime meridian 

 from which longitude may be reckoned. 



The establishment of an initial or prime meridian as the recognized 

 starting point of time-reckoning by all nations, aflfects the whole area 

 of civilization, and conflicting opinions may arise concerning its posi- 

 tion. Its consideration must therefore be approached in a broad, 

 cosmopolitan spirit, so as to avoid ofience to national feeling and 

 prejudice. 



