STRIKING APPARATUS. 



the air, which resists them with a force which increases in the 

 proportion of the square of the velocity of the rotation. Thus, 

 if the velocity of rotation be in- 

 creased in a two-fold ratio, the "" 

 resistance to AA' B'B is increased 

 in a four- fold ratio ; if the rota- 

 tion be increased in a three-fold 

 ratio, the resistance is increased 

 in a nine-fold ratio, and so on. 

 It is evident, therefore, that by 

 this very rapid increase, the re- 

 sistance to the motion of the train 

 must soon become equal to the 

 descending force of the weight, 

 and then the motion will become 

 uniform ; for if it were to increase, the resistance would exceed 

 the force of the weight, and would slacken the rate of motion ; 

 and if it were to decrease, the resistance being less than the force 

 of the weight, the latter would accelerate the motion. In either 

 case the motion would immediately be rendered uniform. 



Projecting from the face of the wheel H (fig. 31) there is a small 

 pin which rests upon the end m of a lever m n, which turns upon 

 the centre n. The lever m n when in this position stops the 

 motion of the striking train. Behind the same lever m n, and 

 projecting from it, there is another piece, which in the position 

 represented in the figure rests in a notch of the wheel o p, lying 

 behind the striking train, and indicated in the figure by dotted 

 lines. Around the edge of this wheel there is a series of similar 

 notches at unequal distances, determined in the manner which we 

 shall presently explain. 



Upon the face of the wheel G, at equal distances one from 

 another surrounding it, a series of pins project, which, as the 

 wheel turns, successively encounter a lever 6, which plays^upon a 

 centre a. Upon the same centre a is fixed the handle a a' of the 

 hammer A by which the bell v is struck. A spring fixed upon 

 the same centre a causes the lever b to rest in the position repre- 

 sented in the figure, and to return to that position if raised 

 from it. The hammer handle a a' is made either elastic itself or 

 is provided with a like spring. 



When the wheel G is made to revolve at a uniform rate by the 

 weight E, regulated by the fly K, the pins projecting from the face 

 of the wheel G encounter successively the lever &, and raising it, 

 throw back the handle a a' of the hammer which is in connection 

 with the lever b. After the pin has passed the lever b the latter 

 is brought back with a jerk by the action of the spring, and the 



