Page:Popular Science Monthly Volume 6.djvu/153

Rh the right fore-foot is about to reach the ground, the left hind-foot has just risen.

At the third or last beat of the pace, the position of the animal is that given in Fig. 15. The moment chosen is that in which the right foot alone rests on the ground, and is about to rise in its turn.

 —A, determination of each of the successive times; B, determination of the number of feet which support the body at each instant.

The gallop in four-time differs from that which has just been described only in this particular, that the impacts of the diagonal biped, which constitute the second beat of that gallop, are in this case disunited and give distinct sounds. This is shown in Fig. 16. According to this notation, the body, at first suspended, is borne successively on one foot, on three, on two, on three, and on one, after which a new suspension commences.



The full gallop, which is a very rapid pace, is in four-time. The impacts of the hinder-limbs, however, follow each other at such short intervals, that the ear can only distinguish one of them; but those of the fore-legs are notably more separated, and can be heard distinctly as two sounds. The notation of the full gallop (Fig. IV) confirms this. Another character of the full gallop is, that the longest period of silence takes place during the pressure of the hinder-limbs. The time of suspension appears to be extremely short. The reactions in the full gallop reproduce with great exactness the rhythm of the impacts. Thus it is observed that, at the moment of the almost synchronous impacts of the two hinder limbs, there is a sharp and prolonged reaction, after which two less sudden reactions take place, each of which corresponds with the impact of one of the fore-feet. The irregular line in Fig. 17 is the tracing; of the reactions at the withers.

Many other points relating to the locomotion of the horse, such as