THE GAITS IN PARTICULAR. 561 



When the gallop is true, the line of gravitation, as Raabe l has 

 truly observed, is always nearer to the concentric lateral biped than to 

 the other, on account of the inclined position of the body. Hence 

 this biped is more fatigued, because it must support during the whole 

 time the excess of weight of which its congener is relieved. This fact 

 becomes very apparent in ring-horses, which perform always in the 

 same style in circuses in rings only 14 metres in diameter. 



When the gallop is broken, the horizontal displacements of the 

 centre of gravity are more extensive than under ordinary conditions. 

 This follows from the fact that the members, in striking the ground, 

 succeed each other alternately in lateral instead of diagonal bipeds. 

 (See the notation of Fig. 237.) As to the longitudinal displacement, 

 it is eifected laterally, that is to say, from a posterior member to the 

 anterior of the same side. These two peculiarities render the gait 

 more tiresome to the rider and destroy the stability of his position in 

 the saddle. 



Reactions. It suffices to glance over Figs. 238 and 239 to 

 ascertain that the pressure of the feet upon the ground must be 

 much more energetic in the gallop than in the walk or the trot. The 

 descent of the fetlock and the closing of the superior angles during 

 each phase of dispersion of concussion is here much greater. As 

 M. Marey 2 has observed, the horse is obliged not only to support 

 the weight of his body, but also to propel himself by violent impul- 

 sions. The greatest effort seems to appertain to the first beat. 

 The body, raised an instant, again falls, and one foot only sustains 

 this shock. 



The reactions which are produced at the withers are represented 

 in Fig. 240 (upper line R) by an undulating curve, which continues 

 during the whole of the contacts of the feet with the ground. 



Marey considers that the minimum elevation of the curve corre- 

 sponds to the moment when the feet are in the air, and therefore he 

 concludes that the so-called phase of projection is in reality only a 

 simple suspension, without any ascending movement of the body. 



We regret to entertain a different opinion, for these statements are 

 not in accord with the daily observations of all riders, or with those 

 which can be made upon instantaneous photographs, notably those of 

 Mtiybridge and Anschiitz. From the latter, which remove all doubt, 

 it is easy to prove that the distance of the back above the ground 



1 Raabe, Examea des allures, Paris, 1857, p. 53. 



2 Marey, loc. cit., p. 174. 



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