TIME-KEEPING IN LONDON 



333 



broken, the relay-bars go back to their normal position, the train- 

 work moves away the cam (C), and restores the vertical bars to con- 

 nection with their instruments. 



The apparatus which effects the shunting at one o'clock is somewhat 

 different in construction. The pin (P, Fig. 9) falls into the notch (N'), 



_4_ 



Fig. 9. Diageam showing Klecteic Connections of Clock ttitii Cheokophee. 



a pin (p) on the wheel (W) coming against the arm (I) of the forked 

 lever (Y) raises the flexible arm (G) against the upper contact (D), so 

 that the circuit of the local battery (U) is closed through the starting 

 magnet (M), which operates the one o'clock train- work. 



Wires which receive both the ten and one o'clock signals pass 

 through both switching arrangements. 



For the hourly currents on metropolitan lines the relay (V") serves, 

 by closing the circuit of the battery (U) at the contact (K), the rest 

 of the apparatus remaining inoperative. 



