640 THE APPLICATIONS OF PHYSICAL FORCES. [BOOK v. 



the left, brings the left hand peg into contact with c ; the contact on 

 the other side is now closed ; the electro-magnet E acts on the left- 

 hand branch, arid the bell c, in turn, falls on the side A of the crossbar, 

 and so on indefinitely. 



M. Froraent's electric clock, Fig. 420, owes its motion to the 

 periodical action of a little weight, p, which comes into contact with 

 a lateral screw every time the circuit is closed. The regulator is 

 arranged and works in this way : The pendulum B, suspended by an 



Fro. 419. Verite's electric clock. 



FIG. 4-20. -Froment's electric dock. 



isochronous spring, is in direct communication with the positive pole 

 of the battery. The other pole is connected with the wire of the 

 electro-magnet E, which communicates with a spring band, at the end 

 of which is soldered the weight p. The branch R of a lever RL sustains 

 this band and weight when the circuit is open, the other branch, L, 

 carries an armature which is attracted by the electro-magnet every 

 time the circuit is closed and the current passes. Now the opening 

 and closing of the circuit are produced at each successive oscillation 



