CYLINDRICAL ESCAPEMENT. 



pallets, which project from the axis of the balance-wheel at right 

 angles with each other, one of which acts at the top, and the 

 other at the bottom of the escapement- wheel G, the axis of which 

 is horizontal and the wheel vertical. These pallets, as the 

 balance-wheel oscillates, engage alternately in the teeth of the 

 escapement-wheel exactly in the same manner as do the pallets of 

 the anchor of the escapement attached to the pendulum already 

 described. This form of escapement was long the only one used, 

 and is still continued in the more ordinary sorts of watches. 



It has, however, been superseded, in watches and chronometers 

 where greater precision is required, by others of more improved 

 construction. 



40; In pocket watches, where great flatness is required, the 

 cylindrical escapement is used, in which the axis of the balance- 

 wheel, instead of having pallets attached to it, is formed into a 

 semicylinder, having a sort of notch in it, as represented on an 

 enlarged scale in fig. 21. The semicylinder a 6, is cut away at c, 

 through about half its height. The axis A B, fig. 22, of the 

 escapement- wheel is vertical, and the teeth raised at right angles 



Fig 21. 



Fig. 22. 



to its plane, and therefore parallel to its axis, have the peculiar 

 form represented in the figure. As the balance-wheel oscillates 

 on the one side and the other, the semicylinder upon its axis 



p 2 35 



