The bit and the spur are two means made use of to bring them into order, the former for their guidance, and the latter to make them increase their motion. The mouth does not appear formed by nature to receive any other impressions than that of taste and appetite; but there is so great a sensibility in the mouth of a horse, that, in preference to the eyes and ears, we address ourselves to it, to make him understand our pleasure; the slightest motions, or pressure of the bit, is sufficient to inform and determine his course; and this organ of sense has no other fault than its perfection. Its too great sensibility requires particular management, for if it is abused the mouth of the horse is spoiled, and rendered insensible to the impression of the bit: the senses of sight and hearing cannot be dulled in this manner; but in all likelihood it has been found inconvenient to govern horses by these organs; besides, signs given them by the sense of feeling have more effect on animals in general than those conveyed by the eyes or ears. The situation of the eyes of horses, with relation to those who mount or conduct them, is very unfavourable; and, though they are frequently conducted and animated by the ear, it appears that the use of this organ is limited to common horses, because in the menage they are seldom spoken to; in fact, if they are well broke the smallest pressure of the thighs, or most trifling motion of the bit, is sufficient to direct them. The spur is even useless, or at least it is only made use of to force them to violent motions; and as through the folly of the rider it often happens, that in giving the spur he checks the bridle, the horse finding himself excited on one side, and kept in on the other, only prances and capers without stirring out of his place. By means of the bridle horses are taught to hold up their heads, and keep them in the most graceful position, and the smallest sign or movement of the rider is sufficient to make the horse shew all his different paces; the most natural is perhaps the trot, but pacing and galloping is more pleasant for the rider, and these are the two paces we particularly endeavour to improve. When the horse lifts up his fore legs to walk, this motion should be performed with spirit and ease, and the knee sufficiently bent. The leg lifted up should seem as if suspended for a moment, and when let down the foot should be firmly rested on the ground without the horse's head receiving any impression from this motion, for when the leg suddenly falls down, and the head sinks at the same time: it is usual to ease the other leg, which has not strength to support the whole weight of the body. This is a great fault, as well as that of carrying the foot too far out or in. We should also observe, that when he rests on his heel it is a mark of weakness, and when he rests on the forepart of his hoof it is a fatiguing and unnatural attitude that he cannot long support.