In the school-gallop, the most finished form of the pace, the horse is so closely united that the secondly planted hind leg reaches the ground before its diagonally disposed fore leg, and we have again a gallop of four beats.
It will be seen, then, that the galloping horse should be in gallop right in turning to the right, in gallop left in turning to the left, so that a hind leg will be under the centre of gravity as a bearer of the weight when the turn is made. If a horse, in gallop left, be turned shortly to the right, it will almost invariably fall, for as the horse leans over at the turn there will be no support under the mass. A horse at liberty instinctively changes the lead in the gallop as circumstances require; but the mounted horse cannot be depended upon to make the change voluntarily, and the rider should demand the change at the proper time.
Before the appearance of "Modern Horsemanship," no one had described how the horse began the change in the gallop, from right to left or from left to right, or how it was performed. Dr. Stillman, the only author who had touched upon the subject, suggested that the horse changed the lead when in air, but this was a manifestly incorrect supposition; for the photographs show that the hind legs are always committed to a certain stride before the horse goes into air. By riding trained horses in the gallop changes before the camera, I discovered when those movements were begun and how they were made, and I was able to explain how the aids should be applied to produce the changes; for previously, it had been a matter of experiment and tentative practice with each horse that had been taught to make the gallop change. The loose explanations in the riding regulations of every army, and even those of such authorities as Baucher and others, prove this assertion. I am somewhat familiar with the writings of nearly all the authors of standard works on horsemanship, from the days of Grisone to the present day, and I cannot recall a passage in any one of them that would indicate a knowledge of how the gallop change was made, or one that gave a rational explanation of how and why the aids should be applied.
The gallop changes must have been successfully demanded from time immemorial, but, as has been said, it was always considered a difficult performance to procure with certainty and precision, and in many cases was made as a turn was begun, the forehand beginning the change which would leave the hind legs false for that stride.
When the photographs proved that the hind legs were committed to a certain order before the horse left the ground in each leap, it was apparent that the change must take place in the hind quarters as soon as the legs of that part were free to change their order; and that the legs of the forehand must make a corresponding change when they were free, when the gallop change would be finished in one stride, without a false step.
To make the horse change, say from gallop right to gallop left, in any stride, the forces must first be fairly united; the right heel should be applied when the forehand is down, and as the hind legs are leaving the ground; immediately thereafter, as the forehand is rising, the left rein should make a slight play which will insure the change in the fore legs, and the change will be completed without a false step and without any disturbance of the pace.
FIG. 88.—WHEEL IN GALLOP