=The upper part of the body easy, flexible, and straight.=
If the upper part of the body is not easy, its stiffness will extend to other parts which should be free to give to the motion of the horse, and thus avoid any shock; if it is not straight, the effect is lost of the perpendicular line upon the horizontal one of the horse's back, which corrects the displacement of equilibrium when the animal is in motion.
=The lower part of the body firm, without stiffness.=
If it were not firm, the spine would bend forward or back from the perpendicular, and derange the center of gravity, with dangerous results in case the horse made a sudden bound; but there must be no stiffness, as that detracts from the ease and suppleness indispensable to a good seat.
=The shoulders well back, and on the same line.=
Well back, in order to give the lungs full space to breathe, and to prevent stooping. The most common fault among ladies who ride is, that the right shoulder is held farther forward than the left, which is not only ungraceful, but bad for the horse, as the rider's weight does not come evenly on his back.
=The arms falling naturally, the elbows being held close to the body without stiffness.=
If the arms are held as if tied to the body, or if the elbows are stuck out, the wrists and hands can not guide the horse with ease.
Forming with the upper arm a right angle, of which the elbow is the apex, in order to give the wrist an intermediate position, whether the hand is held high or low.
Because, if the wrists are held too low, the rider will get into the habit of resting her hands on her right knee, and will consequently neglect to occupy herself with her horse's mouth.
In order to give the rider a fixed intermediary position between the movements of the hands forward, to the left, or to the right, by which she governs her horse: if the wrists are held farther apart, the elbows will appear pinioned to the sides; if nearer together, the elbows, on the contrary, will stick out in an angle.
I attach great importance to this disposition of the reins, as it gives a novice confidence, makes it easier for her to sit square in the saddle, and easier also to manage her horse.
=The fingers firmly closed, facing each other, with the thumbs extended on the ends of the reins.=