508 THE EXTERIOR OF THE HORSE. 



The displacements of the centre of gravity occur in a trans- 

 verse and an antero-posterior sense. 



1st. In the transverse displacement, this centre is carried, during 

 each time, alternately from left to right and right to left, from E, F, 

 G, upon the lines AB, CD, A'B', etc. (Fig. 197), which unite the two 



Fig. 197. 



lateral bipeds on the ground. This movement produces a sort of 

 rocking, which, when exaggerated, may occasion a fall sideways. 



2d. The vertical displacements take place during each period of 

 contact, and can be represented by the arcs EF, EG (Fig. 198), whose 



Fig. 198. 



height is always small, since the gait, being very unstable, is low and 

 quick. This is the reason why the ambler is an easy and pleasant 

 mount, so appreciated by persons who object to the stronger reactions 

 of the gallop or the trot. 



The great speed of this gait is explained by the eccentric position 

 of the base of support, which increases the instability of the equilib- 

 rium, and, consequently, the speed. 



According to M. Lenoble du Teil,' the velocity should be 2.40 m. 

 per second, as in the ordinary walk, for a horse 1.60 m. high. The 

 velocity of this gait, it is perceived, varies in a great measure accord- 

 ing to the conformation, the energy, and the endurance of the animals. 

 In 1844 and 1845, in concert with H. Bouley, we observed a mare, 

 known in Paris by the name of Am^ricaine, which several times, 

 and with the same success on each occasion, ambled the whole distance 

 from Paris to Fontainebleau against thoroughbred horses going at a 

 gallop. 



The amble, in this instance, was leaped, as, indeed, it appears to 

 be whenever its speed attains that of the fast trot. According to M. 

 Lenoble du Teil,^ this particular form of ambling is well known to 

 the Germans, who call it t\\Q flying amble. 



> Lenoble du Teil, loc. cit., p. 57. 2 Lenoble du Teil, note communiqu6e. 



