TIME-KEEPING IN LONDON. 



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together, and each group has a separate relay, in order that the shorter 

 may not unduly deprive the longer lines of their share of the current. 

 The four relays are all worked by the hourly signal from Greenwich, 

 and therefore act simultaneously. The lines of the Metropolitan group 

 are used only for time purposes, and are therefore always connected 

 with their relay, and distribute the signals hourly. But the lines of 

 the other groups are in use generally for ordinary telegraphic pur- 

 poses, and distribute time-signals only at ten and one o'clock. At these 

 hours, therefore, the wires must be switched off from their ordinary 

 duty, and placed in communication with their respective relays to be 



