PART III
THE SCIENTIFIC EQUITATION
CHAPTER XXII
THE DIAGONAL EFFECT
THE name, "High School" has long been used and is still employed to designate a system of education which trains a horse to execute in the ring of a circus the low and high airs and the various figures of manege. It is a special kind of equitation, for which the state of equilibrium is not important. Baucher, Fillis, Franconi, and other civilian masters of the art have exhibited their horses in the circus, not alone for the immediate financial profit, but still more to make their systems known and appreciated. It was, in fact, from the circus that Baucher and Fillis were called by various European governments to teach their systems to army officers.
These masters, however, had already accepted the anatomical principles of Benton, Borelli, and Bishop, who, in their discussion of animal motion, emphasize the fact that, at walk and trot, the horse advances by the diagonal movement of its limbs. But in accepting this doctrine of locomotion, these masters at once comprehended that the lateral or direct effects of the two older schools are in flat contradiction to the newer ideas of horse anatomy. They found it necessary, therefore, to create the diagonal effects, in order to be en rapport with the movement in diagonal biped.
The horses exhibited by these masters executed all the movements of the high and low airs, but were maintained continually in the state of equilibrium; and they had gait, speed, and manners. So, to emphasize the distinction between their systems and those of the circus, the masters gave to their principles the name équitation savante. The term has been accepted by horsemen the world over, both in the armies and outside. Unfortunately, the only translation into English seems to be the very inadequate "scientific equitation."
As a matter of terminology, the right diagonal biped means the right fore leg and the left hind one; the left diagonal biped, left fore and right hind. Consequently, the right diagonal effect has to mean the effect produced by the right rein and the rider's left leg; while the left diagonal effect is that of the left rein and his right leg.
The equilibrium, which is the foundation of the whole scientific equitation, can be obtained only as the result of two forces opposed to one another, the one pushing the horse forward and the other holding him back. The first of these forces arises from the effect of the rider's legs: the second from the effect of his hands by way of the reins and the bits. If, let us say, the rider exerts ten degrees of effect with his legs to send the horse forward, and at the same time exerts ten degrees of effect with his hands to prevent this movement, the horse, between these two forces, must concentrate its native powers, and establish a center of gravity. The result is equilibrium, that is to say, balance. The effects of the legs are effects of impulsion. The effects of the hands are effects of retention. Thence arises the equestrian axiom: Equilibrium is the consequence of effects of opposition.
Suppose, then, that the horse is being maintained in equilibrium between ten degrees of impulsion and ten degrees of opposition. If, now, the impulsion is increased from ten degrees to fifteen, the opposition still remaining at ten, the horse must move forward, with the condition of equilibrium still maintained.
Precisely here lies the difference between the scientific equitation and the lateral or reasoned. The former, to produce movement forward, keeps the same opposition as before, but increases the impulsion. The others cease the opposition, and thereby allow the equilibrium to disappear. These last cannot do otherwise. They are employing the lateral effect only. Therefore, they cannot maintain the effect of opposition against a mechanism which is driving itself forward by a diagonal action. Only the diagonal effect can maintain opposition while the animal moves in diagonal.
The reader will note that it is always from the fore leg involved that the right or left diagonal biped takes its name. This, in my opinion, is a mistake. The hind leg is the one which gives the impulse and is the cause of every movement. The action of the fore leg is merely the consequence. It would, therefore, have been more logical to have named the bipeds from the hind legs; and more in accord with the equestrian maxim, "Forward, forward, always forward." This means impulsion, and impulsion is possible only by the effects of the rider's legs acting on the hind limbs of the animal.
It must, of course, be understood that when I discuss these motions in diagonal, I am considering only a horse in the state of equilibrium. Moreover, when any master speaks, let us say, of the right diagonal effect and the use of the right rein and the left leg, he does not mean that the left rein and the right leg are to cease their effects. What he means is that this rein and that leg are to increase theirs. Otherwise, the horse will turn its body, its spine in the dorsal region will no longer remain straight, and the forward impulse will disappear.
To accustom horse and rider to the diagonal effect, they should execute mounted the lateral and direct flexions, and mobilization by the reversed pirouette and backing. If, however, at the beginning of practice in the diagonal effect, a young rider training a young horse is confused in his efforts, it is better to begin the rotation by the diagonal effects on foot. For this, supposing that the movement is from left to right, the trainer places himself exactly as for the direct flexion, except that he holds in his right hand the right reins of both curb and snaffle and also the whip. By means of these two reins he secures a partial flexion to the right; and at the same time, by means of the curb rein held in his left hand, he maintains the head, mouth, and neck inclined to the right. Then, with the whip, he makes the animal execute the mobilization of the hind quarters from left to right, step by step. After some practice at these rotations, both from right to left and left to right, the trainer mounts and repeats the mobilizations by the same effects, but using his leg instead of the whip. But an experienced trainer begins these rotations by diagonal effect, mounted.
For the rotation from left to right, by the right diagonal effect, the cavalier mounted, the horse standing still and in equilibrium, both reins of the bit and the left rein of the snaffle are taken in the left hand, and the right rein of the snaffle is taken in the right hand. The left hand keeps the horse's head perpendicular, the "in hand" position, while the right hand, by a light opposition on the right snaffle rein, inclines the horse's head to the right. Meanwhile, the effect of the rider's right leg impels the horse forward, and the left leg, increasing its effect, pushes the haunches toward the right, the animal's right fore leg gaining a little ground to the front. (Figures 21, 22.)
The rotation must be executed calmly and step by step. It is completed when the horse has aboutfaced. In the rotation from left to right, the action of the rider's right leg is absolutely necessary for maintaining the forward impulse while the haunches wheel at the effect of the rider's left. The rotation is stopped at its completion by the effect of the rider's right leg; not by the cessation of the effect of his left. The rotation can be done also at the trot, but only upon a circle, and only after the horse has learned to make two pistes, which makes the figure a half-passage. The rotation at the gallop is very complicated, and cannot be performed until the horse can do the two pistes at a gallop.
The pirouette is asked only by the direct flexion of the mouth and neck and can be done at trot and gallop. Backing is asked by the diagonal effect. It is done step by step, and needs great care to avoid wear and tear of the hocks.
The trot is executed by the action of diagonal bipeds, precisely like the walk except that each biped, remains a longer time off the ground. (Figure 23.)
The gallop is the same as the run, but slower. The canter is still slower than the gallop. The run is natural and instinctive to the horse; the gallop is taken and held under the control of the rider; the canter is an artificial gait given by the cavalier.
These three gaits have given rise to so many theories that the result has been and still is an endless confusion. Some theorists teach that run and gallop are executed by the lateral bipeds. All such 
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 movement, yet without occasioning too much surprise. But the effects of right leg and right hand will have a tendency to send the haunches to the left rather than forward. Therefore the rider's left leg has also to be closed, partly to prevent the haunches from getting away to the left, and partly because the attack of the right leg first attracts the right hind leg below the center of gravity, and then calls the left hind leg to its support, the front legs being raised by the effects of the right hand, the right ready to extend to receive the weight as the foot comes back on the ground.
All these effects have to be executed with decision and precision, in a word, with equestrian tact. It is this employment of this left leg of the rider to maintain the horse straight at the beginning of the gallop to the right, which has created the mistaken theory that it is the function of the left leg to start the gallop to the right, and of the right leg to start the gallop to the left. Such was the foundation of the theory of the gallop executed by the diagonal biped.
The motion in diagonal at the gallop shows itself only when the horse changes lead from one lateral biped to the other. With the gallop on the right hind leg, this leg, which is giving the impulse, is always in front of the left, which is the more continued support. But for the forcible change of lead from right to left, the impulsion alters first, and after this the support passes to the other leg. The 
Note, now, the difference between Baucher, Fillis, and myself. Baucher says, "I do not try to explain something inexplicable; it is for the equestrian tact of the esquire to discover how to execute the movement." Fillis says, "I make my horse gallop to the right by the effect of my left rein and my left leg. To change the lead, I employ the opposite effects."
I, on the contrary, sum up my directions thus: By the effect of my right rein, I lift the horse's right fore leg. (Figures 18-22.) By the effect of my left leg, I raise the horse's left hind leg—the diagonal effect. If, then, the horse's left hind leg is off the ground, his right hind leg is pressed forcibly against the ground. (Figure 18.) Thereupon, by the effect of my right snaffle rein, I compel the horse to extend its right fore leg. (Figure 22.) With my right rein and my left leg—diagonal effect—I obtain the right diagonal biped. With my left rein and my right leg—again diagonal effect—I obtain the left diagonal biped for the walk and trot. (Figure 21.) With my right rein, I raise the horse's right fore leg, while with my right leg I raise the horse's right hind leg—lateral effect. This right hind leg will come to the ground under the center of gravity, and drive the body forward. The right fore leg will thereupon extend forward for the gallop to the right—lateral biped. (Figure 25.) My body, being inclined forward, will carry forward the center of gravity, and the gallop will continue until other forces intervene.
And there is all the demonstration of the theorem and the solution of the problem!
Every horse, however, has one side which is more supple than the other; and it is better to begin practice in changing lead by shifting from the less supple to the more supple side.
Suppose, for example, that the more flexible side is the left. My horse being straight, I start it galloping to the right, by the method given above, and keep it going straight. I then reverse all my effects. If the horse changes lead, I stop it as soon as may be, and recompense its obedience. When it is completely calm, I begin again, galloping to the right. After several steps, I again change; and again recompense.
When the horse understands the change of lead from right to left, I proceed in the same way to teach the change from left to right. At first, I ask the change only after the horse has galloped ten or fifteen steps on the same foot. When the horse manages this, I reduce the interval progressively, first to six or eight steps, then to four, and finally to only two. I need not say that this training takes time that cannot be measured by days or lessons. I progress slowly, ask very little, rest my horse a great deal, and keep calm. I do not, under any circumstances, permit my horse to choose the lead for itself, nor to change foot on its own initiative. It is essential that the rider always impose his mastership upon the horse's intelligence. The rules are: short lessons, precision helped by moderation, recompenses, no overexertion or fatigue. With these, success is assured.
THE FALSE GALLOP
BY "false gallop," we mean galloping on one side when turning to the other. A horse is also said to gallop false when it leads with either side, after the rider has signaled for the other.
A horse galloping in a straight line leads with whichever side the rider determines. If this chances to be the left, the rider must change the foot before making a turn to the right. Otherwise the horse will gallop false.
Turning on the wrong foot is always dangerous. In turning, for example, to the right at the gallop, the center of gravity will be displaced toward the right, and the right lateral biped will take the longer step. All this occurs naturally if the horse is galloping to the right. But if it is galloping to the left, the right leg cannot reach out to receive the additional weight, and the horse may cross its legs and fall.
The false gallop is, nevertheless, employed in training the horse to gallop equally on the two sides, and also in teaching it the change of lead on a straight line without change of hand. But it should be understood that in all such cases the false gallop is always asked by the rider, never taken by the horse at its own will. It is essential to a well-trained saddle horse that it gallop equally to either side, and always at the signal of the rider.