Wheels may also be briefly noticed here. A horse may wheel or turn on his own ground, on three pivots,--on his centre, on his fore feet, and on his hind feet. In all these, the hand directs all before the horseman, and the heel all behind him. In wheeling on centres, the hand and heel operate together--the hand leading the shoulder round--the leg directing the croupe, by which means, in going about, the fore feet describe one half-circle, and the hind feet another. Here the aids of the hand, body, and legs, must exactly correspond; and the degree of appuy must be merely such as will carry its aid into effect; for, if the appuy is too weak, the horse will advance over his ground, and if too strong, he will retire from it. On terminating the wheel or quarter circle, the about or half-circle, or the about and about, or whole circle, the hand, the body, and leg, must instantly resume their proper position. The wheel on the fore, and that on the hind feet, are still more rarely of use in common practice. _Stops in the Walk._ Horses and horsemen generally stop by a gradual cessation of action, in a time and distance which depend on circumstances. As to character, however, the stop, when properly performed, is an instant cessation of advance, without any previous indication. When the stop is properly performed, it shows the great superiority of the rider’s hand over the horse. It confirms him in obedience, unites him, supples the haunches, and bends the houghs. Much mischief, however, may occur from a too frequent or injudicious practice of it. The perfection of the stop consists in the action ceasing at the finish of a cadence, without breaking the previous time; and in the horse being so balanced on his haunches, and so animated, that, with liberty given, he can advance with the same rapidity as before. In performance, the time to be seized is when the first part of the cadence is coming to the ground; so that its finish completes the stop. If this is not done, the cadence will be broken, and the stop rendered irregular. At such a moment, the stop is performed by the rider bracing his arms to his body, holding both reins equally and firmly, drawing the fingers towards the body, closing for an instant both legs, to press the horse up to the bridle, and throwing the body back, with precisely such strength of all the muscles as is proportioned to the effect; all this being done at the same instant, and making but one motion. If the rider do not close his legs, the horse may not bring his haunches under, the stop will be on the shoulders, and its effect will be destroyed.