theories are the product of philosophizing by writers who do more riding with a pen than with hands and legs on a horse's back.
The saddle horse is useful to mankind only by virtue of its locomotion. This locomotion is the consequence of impulsion; and impulsion is given only by the animal's hind legs. To drive the body forward, therefore, it is absolutely necessary that the horse should have one or two feet on the ground. A foot in the air, so long as it remains in the air, can have no effect.
But if, let us say, the right hind foot is on the ground, the right hind leg may deliver its thrust either to the right or to the left fore leg. In the first case, the right lateral biped is set in motion, in the second case, the left diagonal biped.
In order, then, to pass from standing still, or from walk or trot, to the gallop upon the right lateral biped, the rider throws his entire weight upon the right lateral biped, and at the same time, by a quick inclination of the body forward to the right, the rider places the horse in the position to gallop. It then remains only to give the action to the whole machine, the legs of the horse moving in accord with the gait asked.
This action will be given by the effect of the right leg of a rider, who at the same time closes the fingers of the right hand upon the right rein of the curb bit or snaffle. These effects of the right leg and right hand have to be executed by a quick
