Page:Popular Science Monthly Volume 6.djvu/149

Rh in a forward propulsion, with a scarcely perceptible impulsion of the body in an upward direction. This agrees with the theory quite generally admitted, that the fore-legs have little to do in the normal pace, except to support alternately the fore-part of the body, while to the hind-limbs belong the propulsive action and the tractive force exerted by the animal. Fig. 12 is a representation of the horse at a walking-pace. The instant is marked in the notation by a dot.



The gallop comprises all those paces in which irregular impacts of the feet upon the ground recur at regular intervals. Most writers distinguish three kinds of gallop by the rhythm of the impacts, and name them, according to this rhythm, gallop in two, three, and four time. The most common kind is the gallop in three-time, from which the tracings in Fig. 11 have been obtained. At the commencement of the figure the animal is suspended above the ground; then comes the impact P G, which announces that the left hind-foot touches the ground. This is the foot diagonally opposed to that which the horse places forward in the gallop, and whose impact A D will be the last produced. Between these two impacts and in the middle of the interval which separates them, comes the simultaneous impact of the two feet forming the left diagonal biped. The superposition of the notations A G, P D, clearly shows this synchronism. In this series of movements the ear has therefore distinguished three sounds at nearly equal intervals. The first sound is produced by a hinder-foot, the second by a diagonal biped, the third by a fore-foot. Between the single impact