Let the Horseman then place himself at once upon his Twist, sitting exactly in the Middle of the Saddle, let him support this Posture, in which the Twist alone seems to sustain the Weight of the whole Body, by moderately leaning upon the Buttocks; let his Thighs be turned inward, and rest flat upon the Sides of the Saddle, and in order to this, let the Turn of the Thighs proceed directly from the Hips, and let him employ no Force or Strength to keep himself in the Saddle, but trust to the Weight of his Body and Thighs; this is the exact Equilibre; in this consists the Firmness of the whole Building; a Firmness which young Beginners are never sensible of at first, but which is to be acquired, and will always be attained by Exercise and Practice.
I demand but a moderate Stress upon the Buttocks, because a Man that sits full upon them, can never turn his Thighs flat upon the Saddle; and the Thighs should always lay flat, because the fleshy Part of the Thigh being insensible, the Horseman would not otherwise be able to feel the Motions of his Horse. I insist that the Turn of the Thigh should be from the Hip, because this Turn can never be natural, but as it proceeds from the Hollow of the Hip-bone. I insist further, that the Horseman never avail himself of the Strength or Help of his Thighs; because, besides that he would then be not only less steady, but the closer he prest them to the Saddle, the more would he be lifted above it; and with respect to his Buttocks and Thighs, he ought always to be in the Middle of the Saddle, and sit down full and close upon it.
Having thus firmly placed the immoveable Parts, let us pass on to the first of the Moveable; which is, as I have already observed, the Body or Trunk, as far as to the Waist: I comprehend in the Body or Trunk, the Head, the Shoulders, the Breast, the Arms, the Hands, the Loins, and the Waist, of the Horseman.
The Head should be free, firm, and easy, in order to be ready for all the natural Motions that the Horseman may make, in turning it to one Side or the other: It should be firm, that is to say strait, without leaning to the Right or Left, neither advanced, nor thrown back; it should be easy, because if otherwise, it would occasion a Stiffness, and that Stiffness affecting the different Parts of the Body, especially the Back-bone, they would be without Ease, and constrained.
The Shoulders alone influence by their Motion the Breast, the Reins, and the Waist.
The Horseman should present or advance his Breast; by this his whole Figure opens and displays itself: He should have a small Hollow in his Loins, and should push his Waist forward to the Pommel of the Saddle, because this Position corresponds and unites him to all the Motions of the Horse. Now, only throwing the Shoulders back produces all these Effects, and gives them exactly in the Degree that is requisite; whereas, if we were to look for the particular Position of each Part separately, and by itself, without examining the Connection that there is between the Motions of one Part with those of another, there would be such a Bending in the Loins, that the Horseman would be, if I may so say, hollow-back'd; and as from that he would force his Breast forward, and his Waist towards the Pommel of the Saddle, he would be flung back, and must sit upon the Rump of the Horse.
The Arms should be bent at the Elbows, and the Elbows should rest equally upon the Hips; if the Arms were strait, the Consequence would be, that the Hands would be infinitely too low, or at much too great a Distance from the Body; and if the Elbows were not kept steady, they would of consequence give an Uncertainty and Fickleness to the Hand, sufficient to ruin it for ever.
It is true, that the Bridle-hand is that which absolutely ought to be steady and immoveable, and one might conclude from hence, that the Left-elbow only ought to rest upon the Hip, but Grace consists in the exact Proportion and Symmetry of all the Parts of the Body, and to have the Arm on one Side raised and advanced, and that of the other kept down and close to the Body, would present but an awkward and disagreeable Appearance.
It is this which determines the Situation of the Hand, which holds the Switch. The Left-hand being of an equal Height with the Elbow, so that the Knuckle of the Little-finger, and the Tip of the Elbow, be both in a Line; this Hand then being rounded neither too much nor too little, but just so that the Wrist may direct all its Motions; place your Right-hand, or the Switch-hand, lower and more forward than the Bridle-hand; it should be lower than the other Hand, because if it was upon a Level with it, it would restrain or obstruct its Motions; and were it to be higher, as it cannot take so great a Compass as the Bridle-hand, which must always be kept over against the Horseman's Body, it is absolutely necessary to keep the Proportion of the Elbows, that it should be lower than the other.
The Legs and Feet make up the second Division, of what I call the moveable Parts of the Body.