LEGAL TIME IN VARIOUS COUNTRIES—PHILIPPO’T. 949 
process, is one in which the uninitiated is very liable to make errors. 
As the transformation is generally wished quickly, it is important to 
reduce the process to its simplest state. Since the time defined by 
the mean sun is itself purely conventional, it may be used over a 
considerable region with little inconvenience. Thus, for the whole of 
a country may be adopted either the time corresponding to some 
point in its capital or to that of its principal observatory, whichever 
is preferable. 
With the extension of international communication, quite naturally 
certain countries grouped together in the use of the time correspond- 
ing to some place near their center when this did not bring too great 
discordance with the true local time. But this effected only a partial 
solution and trouble still remained when it was desired to pass from 
the time of one group to that of another. An international agree- 
ment was necessary for considering this problem and bringing it to a 
rational solution. 
SYSTEM OF ZONES—DIAL OF 24 HOURS. 
In 1884, a conference, called together at the initiative of the United 
States, met at Washington for the purpose of coming to some under- 
standing among the various nations of the world as to the choice of a 
standard meridian and a universal system of time. Several such 
systems were proposed. The conference, which, moreover, had no 
legal power, limited itself, among other resolutions, to recommending 
the adoption of the meridian of Greenwich and to the expression of 
their sentiment in favor of a universal system of time without com- 
mitting themselves to any special system. However, during their 
sessions the delegates planned a system of hour lunes or spherical 
sectors, which was already coming into use in certain portions of 
North America. According to this scheme, the terrestrial globe is 
divided into 24 sectors, 15° or 1 hour in width; that which extended 
7.5° or 30 minutes of time to the west and to the east of Greenwich 
was adopted as the initial sector. The time in any sector is exactly 
1 hour ahead of the neighboring sector just to the west and 1 hour 
behind that just to the east. 
The advantage of such a convention is that at any instant the 
time indicated by accurately regulated clocks the world over would be 
the same as to minutes and seconds, differing only in the whole hours; 
consequently in passing from the time of one place to that of another 
it is necessary to add or subtract only a whole number of hours. This 
process consists in combining two numbers of never more than two 
figures; thus the task is reduced to its minimum. 
Evidently such a simple system must finally prevail from its own 
merits; consequently we find it coming more and more into use. 
