OF MUSCULARITY AND ELASTICITY 79 



slowly, and an impediment to the working of a 

 machine, at length acquires momentum, so as to 

 concentrate the power of the machine, and enable 

 it to cut bars of iron with a stroke. 



The principle holds in the animal machinery. 

 The elbow is bent with a certain loss of mechan- 

 ical power; but by that very means, when the 

 loss is supplied by the living muscular power, the 

 hand descends through a greater space, moves 

 quicker, with a velocity which enables us to strike 

 or to cut. Without this acquired velocity, we 

 could not drive a nail : the mere muscular power 

 would be insufficient for many actions quite ne- 

 cessary to our existence. 



Let us take some examples to show what ob- 

 jects are attained through the oblique direction 

 of the fibres of the muscle, and we shall see that 

 here, as well as by the mode of attachment of 

 the entire muscle, velocity is attained by the sac- 

 rifice of power. Suppose that these two pieces of 

 wood (Fig. 22) be drawn together by means of 

 a cord, but that the hand which pulls, although 

 possessing abundant strength, wants room to re- 

 cede more than what is equal to one third of the 

 space betwixt the pieces of wood ; it is quite clear, 

 that if the hand were to draw direct on the cord 

 A B, the point A would be brought towards B, 

 through one third only of the intervening space, 

 and the end would not be accomplished. But if 



