LOCOMOTION OF QUADRUPEDS 187 



limbs at one and the same moment. The question is, 

 however, largely simplified, if the quadruped is 

 looked upon as two bipeds walking one behind the 

 other, and presenting various combinations of steps ac- 

 cording to the individual sequence of each. If two men 

 take up such positions, the one in front will reproduce 

 the movements of the fore feet of a horse, and the one 

 behind those of the hind feet. Both will execute in a 

 given time an equal number of steps, but by varying 

 the sequence they can imitate all the paces of a horse. 



In Chapter I. we gave an example of the kind of 

 diagram which is used to represent the successive rise 

 and fall of the fore and hind limbs of a horse, whether 

 at an amble, a walk, a trot, or a gallop. 



Fig. 123 presents a complete table of all the paces, 

 and shows how one is derived from another. In the 

 order in which these diagrams are arranged, beginning 

 from the top in Fig. 123, each differs from the preceding 

 one, inasmuch as the hind feet slightly anticipate 

 the movement of the front. The description under 

 these diagrams suffices in itself to show how authors 

 disagree in the definition of each pace. 



We only give a brief account of these chronographic 

 researches, because we merely want to give a general 

 idea of the principles of the method.* 



To demonstrate the value of this method suffice it 

 to say that these experiments have put an end to most 

 of the disagreements relating to equine paces, and 

 we believe that the results of our investigations are 

 now universally accepted. 



Transition or Passage from one Pace to Another.— It is 

 very difficult for an observer to realize how an alter- 

 ation of pace is effected ; chronography demonstrates 

 this very clearly. This is one of the greatest practical 

 advantages of the method. Let us compare the paces 



* See, for analysis of paces, T.a Machine Animate, pp. H0-18G. 



