COMMON THINGS CLOCKS AND WATCHES. 



interposes itself alternately "between the teeth of the escapement- 

 wheel, stopping them and letting them escape in the usual way. 

 The manner in which the action takes place will be more clearly 

 understood by the figures 23 and 24, in which a view in plan 

 upon an enlarged scale is given of the position of the semicylinder 



Fig 23 



and the teeth of the escapement-wheel after each successive 

 oscillation. 



In fig. 23, the balance-wheel swinging from right to left, 

 throws the convex side A D of the semicylinder before the tooth c 

 of the escapement-wheel, and thus for the moment arrests it, 

 while the side A E of the. semicylinder has turned out of the way 

 of the preceding tooth and has let it pass. The balance -wheel 



Fig. 24. 



then swings from left to right, and the convex side A D of the 

 semicylinder slides against the point of the tooth c. When the 

 edge D of the semicylinder passes the point of the tooth, the latter 

 in slipping over it gives to it a slight impulse, which restores to 

 36 



