140 LECTURE III. 



where feats of horsemanship are displayed. 

 We there see a man stand with one foot on 

 the saddle, and maintain his balance, when 

 his horse is at full speed. This he does 

 when his body is placed horizontally, and 

 with one arm and leg extended in opposite 

 directions. To maintain so perfect a ba- 

 lance, it is necessary that the weight of the 

 body should move in various directions, 

 and with nicely adjusted gradations upon 

 the head of the thigh-bone, and also, that 

 by the motions of the knee and ancle, the 

 support should be equally varied under the 

 incumbent weight. 



The weight of the body is transmitted 

 from the arch of the pelvis, to a second 

 arch made by the form of the heads and 

 necks of the thigh-bones, the basis of which 

 rests against the side of the bone near its 

 top, and protrudes tliat part of the bone 

 outwards, and the bottom in a contrary 

 direction, so as to bring the knee-joint 

 nearly under the general line of gravity of 

 the whole body, and from this joint, the 

 weight is transmitted in a perpendicular 

 direction upon the arch of the foot. 



