THE ELECTRIC TELEGRAPH. 



the electric current could, by means of the conducting wires, be 

 transmitted to any distances, its use in the important problem of 

 the determination of longitudes, became conspicuously apparent. 

 By reference to our Tract on Latitudes and Longitudes, it will be 

 seen that the difference of the longitudes of two places upon the 

 earth's surface is nothing more nor less than the difference of 

 the hour of the day or night, as shown by two well-regulated 

 clocks at the two places. Thus, if while it is 3 o'clock at one 

 place, it is 4 o'clock at the other, the latter is one hour of 

 longitude east, and the former one hour west of the other ; or if 

 it be preferred to express the longitude in degrees, the one place is 

 15 east or west of the other. 



Now since the machinery of the electric telegraph supplies the 

 means of making all the time-pieces of whatever kind, or where- 

 ever placed, which are brought into connection with the same 

 system of wires, move in exact accordance, it is capable of making 

 all the time-pieces in the United Kingdom move in exact accord- 

 ance with the standard chronometer of Greenwich Observatory ; 

 or, to take a still larger view of the principle, it is capable of 

 governing the movement of all the time-pieces of whatever sort, 

 and wherever situated within the range of the vast net- work of tele- 

 graphic wires, which overspreads the European continent, so as to 

 make them move in accordance with any standard time-piece, which 

 may by common consent be adopted as the common regulator. 



Now, if such an uniformity of chronometers were established, 

 the longitudes of all places would be determined by ascertaining 

 by observations on the sun, which are always easy and susceptible 

 of great precision, the local time, that is to say the time which 

 would be shown by a well-regulated clock on the present system. 

 The difference of the two times, that shown by the common 

 standard regulator and that shown by the local clock, would be 

 the difference of longitude between the place in question and the 

 place where the standard regulator would show local time. 



265. In places at great distances asunder, and in different 

 countries, such horological uniformity would, at first, for civil 

 purposes be attended with some inconvenience, since the hour of 

 noon would vary with the longitude. Thus, at a place 15 east of 

 the standard station, the hour of noon would be one o'clock, and at a 

 place 1 5 west it would be 1 1 o'clock. Such an inconvenience would, 

 however, only be felt at the moment of the change of custom. It 

 is obvious that it would be as easy and simple to mark the moment 

 at which the sun passes the meridian by 11 or 1, as by 12. 



Incidentally to such an horological uniformity would arise, 

 however, the convenience that the hour of noon at all places would 

 express their longitude with relation to the standard station. 



