362 SURVEY OF THE COAST 



tlie side at which the wheel is stopped, the tooth is at the top 

 of the inclined plane, and on the side where the top falls be- 

 tween two teeth, a tooth stands below the inclined plane. 

 These two springs have also at their end, each a light brass 

 pin ;*, r reaching to the same inclined planes ;;, p, which ter- 

 minate the cross bar of the pendulum. This inclined plane 

 or pallet meets these pins exactly when the stop i is disen- 

 gaged and the oscillation of the pendulum is completed, and 

 the pins press upon it by the strength of the returning spring, 

 to give to the pendulum the necessary impulse after each 

 oscillation. This impulse is moderated by the screws/,/ 

 and the inclined plane returns, by the same power of the 

 spring, into such a position between two teeth, as brings the 

 screw which is more distant exactly at its lower end. 



The succession of these motions, alternating between the 

 two sides, forms the scapement. Their equality, and coin- 

 cidence with the motion of the pendulum, is adjustable by 

 a small horizontal movement of the bar p, p upon the pen- 

 dulum, which is directed by a short arm or tooth z, turning 

 upon the pendnlnm by means of a key, and fitting in an in- 

 denture of this bar. The motion is stopped by the pressing 

 screw y in the middle of tlie cross bar, the hole being some- 

 what elongated, to admit a small horizontal motion. 



The pendulum s, s is suspended from a strong brass bar 

 u, u passing over the upper ends of both plates of the clock, 

 and supported (agreeably to my suggestion) outside of the 

 pendulum, by a strong square pillar t, which stands under it 

 and is screwed below to the same strong brass plate upon 

 which the clock itself is screwed fast. 



The spring v, which foims the suspension of the pendu- 

 lum, is mounted in a brass piece w, sliding in a slit of the bar 

 u, and there kept in its proper place by a steel pin crossing 

 over the piece u, u. The pendulum rod is adapted to the 

 spring by a steel pin x, crossing both. 



To determine the centre of oscillation in the suspending 

 spring V, this is again perforated, the horizontal diameter of 

 the round hole being exactly in the same horizontal plane 



