4'iS THE IMECHANICAL FUNCTIONS. 



be raised from the ground, the other three feet are 

 always so placed as to form a stable base of 

 support. 



In quick walking, it often happens that quadru- 

 peds raise their fore foot, on either side, a little 

 before the hind foot comes to the ground. This is 

 shown by the impression made by the latter being 

 in the same spot, or even rather in advance of the 

 impression made by the former. But the time, 

 during which the body is thus supported only by 

 two feet, is so short as not sensibly to influence the 

 results. In consequence of the obliquity of the 

 alternate impulses given to the centre of gravity 

 by the successive actions of both the hind legs, a 

 slight degree of undulation is occasioned ; but these 

 undulations are only lateral. 



A trot may be considered as a succession of 

 short leaps made by each set of feet taken dia- 

 gonally ; that is, by the right fore foot, and the 

 left hind foot ; or, vice versa, the one set being 

 raised together a short time before the others have 

 reached the ground : so that during that minute 

 interval of time, all the feet are in the air at the 

 same moment; and during the remaining por- 

 tion of the time, the body is resting upon the two 

 feet placed diagonally with regard to each other. 

 The undulations are here chiefly vertical, instead 

 of lateral, as they are in the walking pace. 



A gallop is a continued succession of longer leaps 

 made by the two hind feet in conjunction. In this 

 case, the centre of gravity is lifted higher from the 

 ground, and is projected in a wide arch, and with 

 great velocity. 



In the amble, both the legs on one side are raised 



