ELECTRO-MOTIVE POWER. 



follows that the same current can simultaneously impart a perfectly 

 regular chronometric motion, to all the clocks dispersed over a 

 large country. 



It remains only to show how the regularity of the intermission 

 of the current can be obtained. This is accomplished by the 

 obvious expedient of putting the commutator, by the motion of 

 which the current is alternately transmitted and interrupted, in 

 connection with a well-regulated chronometer, the pendulum of 

 which shall, in that cas%, itself alternately transmit and suspend 

 the current. 



Among the numerous applications of electric power to be seen 

 in the workshops of M. Froment, are a series of electric clocks 

 constructed nearly upon the principle above described. The 

 motion of each clock is in this case maintained by a small weight, 

 which is alternately raised and lowered upon an appendage of the 

 pendulum by means of an iron counterweight, which is itself 

 alternately raised and disengaged by an electro-magnet, each 

 time that the appendage, by its contact with the weight, opens and 

 closes the voltaic circuit, or, what is the same, transmits and 

 suspends the current. 



The motion of the clock is maintained by a constant weight, 

 without friction and without the application of oil, with great 

 regularity, while the electric current, which is transmitted 

 through it in the intervals of each oscillation, transmits to a 

 distance the chronological indications upon a series of dials, the 

 hands of which are moved by a mechanism, analogous to that 

 Avhich moves the index of an electric telegraph of the kind used 

 on the continental railways. 



208 



