THE ELECTRIC TELEGRAPH. 



Fig. 59. 

 D 



from left to right, the tooth of the wheel, which was previously 

 stopped by the upper surface n' of the pallet c, is allowed to escape, 



and in obedience to the 

 power of the spring or 

 weight, which moves 

 the clock-work, it ad- 

 vances towards m'. 

 Meanwhile the pallet A 

 enters the space be- 

 tween two teeth of the 

 wheel, one of which 

 coming against its lower 

 surface, it stops its 

 motion. "When the an- 

 chor moves back from 

 right to left, the pallet 

 c comes under the next 

 tooth of the wheel. In 

 this manner every move- 

 ment of the anchor to 

 J c the right lets a tooth, 

 which was stopped by 

 the pallet c, advance, 

 and afterwards the pal- 

 let A stops the advance 

 of another tooth, while 

 every movement to the 

 left lets the tooth 

 stopped by A advance, 

 and afterwards the 

 pallet c stops the next tooth which advances on that side. 



Thus each complete oscillation of the anchor, consisting of a 

 motion to the right and a motion to the left, lets one tooth of the 

 escapement wheel, and no more, pass. 



Now if we suppose the pulsations of the current to impart to 

 the anchor by the intervention of the electro-magnet and its 

 appendages a motion of vibration, a tooth of the escapement 

 wheel, and no more than one tooth, will pass the anchor for each 

 pulsation of the current. If the current be suspended the move- 

 ment of the escapement wheel and the clock-work connected with 

 it will be also suspended, and when the pulsation of the current 

 recommences, the oscillations of the anchor, and consequently the 

 motion of the escapement wheel, and the clock-work connected 

 with it, will also recommence. 



152. If the pulsations of the current be regulated (as they may 

 202 



