636 



THE APPLICATIONS OF PHYSICAL FORCES. [BOOK v. 



It appears that in Garnier's regulator the antagonistic force is that 

 of gravity, so that these apparatus can only work on one condition, 

 and that is that they should be placed in a vertical position. The 

 advantage is the constancy and invariability of this force, which is 

 not a property of the elasticity of springs (see Froment's system). The 

 regulating clock was at first an ordinary one with a ratchet-wheel 

 whose teeth came against a fixed spring at each second. This spring 

 was simply a thin sheet of gold in communication with one of the 

 poles of the battery, while the wheel itself was connected electrically 



Fi<;. -117. Froment's electric regulator : the indicator. 



with the other pole. There was in this case in each second, first 

 the passage, and then the interruption of the current afterwards. 

 M. Froment substituted an electric regulating clock for the 

 ordinary one. 



In the indicator, of which Fig. 417 represents the arrangement, 

 the armature MN has at the end nearest n a continuation of copper, 

 to which is articulated a system of two levers, SPQN, whose branches, 

 SQ, QN, tend to straighten themselves when the armature is attracted 

 by the passage of the current. The rod PQ then acts on the bent 

 lever vi, and the catch i pushes on the ratchet-wheel R by one tooth. 



