BONES AND JOINTS OF THE EXTREMITIES 65 



vinced of this by observing people who walk awk- 

 wardly, especially if they walk unequally. Look 

 at their feet, and you will see that one foot goes 

 straight forward, whilst the other is turned out- 

 wards, and that when they come upon the straight 

 foot, they come down awkwardly, and have no 

 spring from it. 



There is another curious circumstance in the 

 form of the thighbone, showing how it is calcu- 



O ' O 



lated for strength as well as freedom of motion. 

 To understand it, we must first look to the dish- 

 ing of a wheel the dishing is the oblique 

 position of the spokes from the nave to the 

 felly, giving the wheel 

 a slightly conical form. 

 When a cart is in the 

 middle of a road, the 

 load bears equally upon 

 both wheels, and both 

 wheels stand with their 

 spokes oblique to the 

 line of gravitation. 

 If the cart is moving 



o 



on the side of a barrel- 

 shaped road, or if one 

 wheel falls into a rut, 

 the whole weight comes 

 upon one wheel : but the 

 spokes of that wheel, which were oblique to the 



