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LONGITUDE AND TIME-RECKONING. 
A FEW WORDS ON THE SELECTION OF A PRIME MERIDIAN TO BE COMMON 
TO ALL NATIONS, IN CONNECTION WITH TIME-RECKONING. 
BY SANDFORD FLEMING, C.M.G., Erc. 
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 measure 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 
centre, 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, affects 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 offence to national feeling and 
prejudice. 
