OP THE UWITED STATES. 361 



aibor going through the clock to bring its other |)inion in the 

 front phite of the clock. 



A stions: piece ol l)rass d is atlapted to tlie |)latc h. pro- 

 jecting a triangular i)iece e dncctly over thcVcapenient wheel. 

 It receives on each side two steel springs w, w^»,//. These 

 are held fast to the piece e by the lower screws if. ,if ; and 

 by means of tlie upper sciews /. / they can he adjusted to 

 more or less pressure in their lower parts. These form the 

 sloping and impelling [)art of the scapenient, which is thcrc- 

 foie regulated I)y them. 



All the four springs have circidar holes, at exactly equal 

 height, immediately below the triangular piece c. and between 

 the two strengthening rims h, //, where they are weakened 

 so much, as to present only a very light S[)ring in their ac- 

 tion upon the scapenient wheel. 



At that place also, the springs are bent, so as to make them 

 tangents to the scapenient w'heel. 



Kach of the spiings ii, ii bears at i a ruby iriounted in brass, 

 and adjustable by the small screws ^, k, projecting from the 

 spring towards the clock, over the scapement wheel, which 

 is stopped by their iailing alternately within the circumfe- 

 rence of the wheel upon a tooth, when tliey are not support- 

 ed by the pendulum in its motion. These rubies stand ten 

 teeth and a half distant from each other. 'I'he distance 

 which they arc allowed to fall is regulated by two screws/, /, 

 going through strong arms reaching up from the bridge c. 

 The screw / is screwed in or out, as the adjustment of the 

 fall of this spring may require. At the end of the springs 

 arc light i)rass pins o.o. projecting ouUvards over the pendu- 

 lum .s. to meet the inclined |)lanes /?, /; at the two ends of 

 the cross bar of the penduhnu. By tins the springs are al- 

 ternately lifted to disengage the scapement wheel. 



The two springs m. m I)car. at the distance of one tooth 

 farther on each side, each an indin'-d plane or |)allet q, q, 

 which are jewelled, and I)y means of which the springs are 

 alternately lifted by the teeth of the scapement wheel, when 

 this slides under them, after being unstopped ; so that on 



