1890-91.] REFORMS IN TIME RECKONING. 135 



which is 1 80° from the meridian of Greenwich. The unit is the smallest 

 and most available measure of time which nature presents to us ; the 

 period occupied by a single rotation of the earth on its axis, and is 

 denoted by two successive solar passages on the zero meridian. 



The " universal day," as defined by the Washington Conference, is 

 actually the time unit, but the term "day" is unfortunate and misleading.* 

 A " day " is always associated with sunlight and darkness, and is in fact a 

 local and superficial phenomenon. Ever}^ separate meridian which can 

 be laid down on the surface of the globe has its definite day with the 

 accompanying and distinct sun-rise and sun-set in each case. It is im- 

 portant to disassociate til's normal unit, the standard measure of time for 

 the world, from our ordinary conception of the day. In order to do so 

 and make clear the fundamental idea of unity of reckoning, it will 

 answer our purpose to find a point of reference equally related to the 

 whole globe. The centre of the earth is this one point identical in 

 relation to every spot on the surface. If we could directly communicate 

 with a standard chronometer at the centre to regulate clocks in all 

 latitudes we would have the means of obtaining the perfect unifi- 

 cation of time-reckoning the world over. Is there no other point 

 where we could establish a common standard? Is not the axis of 

 rotation which passes through the earth's centre common to the whole 

 earth, and would not any point on this axis furnish the position 

 we are in search of? Let us accordingly take one extremity of the 

 axis, the north pole, and in imagination place ourselves in observa- 

 tion at this point, free from local influences. We would find no sun- 

 rise, no sun-set, neither east nor west, every radius of direction would 

 be identical. We would have nothing given but the position of the 

 meridian establishing the time-zero ; from this starting point suppose we 

 divide the horizon into a series of arcs, each of fifteen degrees, making 

 the total number of arcs twenty-four, and through the end of each arc 

 we draw a meridian. The passage of the sun over the zero meridian will 

 indicate the commencement of the time-unit which, according to the 

 usage of centuries, and the decision of the Washington Conference, is 

 divided into twenty-four hours. At the end of the first hour the sun 

 will be over a meridian which may appropriately be termed the first 

 hour meridian ; at the end of the second hour the solar passage will have 

 advanced to another meridian, which may be distinguished as the 



* The question of a proper name for the " time unit " has been considered by the Royal 

 Society of Canada at its May meetings in 1890 and 1891. A time nomenclature committee has 

 been appointed and some progress has been made in this, as well as the question of distinguish- 

 ing the hour meridians. 



