What, then, shall you do first in the way of education? Well, let us see. As Nelly has been broken to harness, she can probably only walk and trot. You, yourself, seem to stick fairly well to the saddle. But how about your own position? Your leathers are a trifle long. They should be of just such length that, when you are in the middle of the saddle, on your seat, not your crotch, with the ball of your foot in the stirrups, your feet are almost parallel with the ground, the heel a trifle lower than the toes. Your toes are below your heels, you see. You should be able to get your heels well down when you settle into your saddle. The old rule of having the stirrups just touch the ankle-bone when the foot is hanging is not a bad one. The arm measure is unreliable, and physical conformation, as well as different backed horses, often require, even in a sound man, odd lengths of leathers.
You should not attempt to ride with your feet "home" until you can keep your stirrup under the ball of your foot without losing it, whatever your horse may do; and when you do ride "home," you should occasionally change back to the ball of your foot, so as to keep in practice. Moreover, you can train a horse much more easily, riding with only the ball of the foot in the stirrup, for you can use your legs to better advantage. My disability obliges me to ride "home" at all times, and I have always found it much more difficult to teach a horse the right leg indications than the left. I have to employ my whip not infrequently, in lieu of my leg. Your stirrup should be larger and heavier, for safety. I don't like your fine, small stirrups; and your saddle should have spring bars, which you should always keep from rusting out of good working order. They have saved many a man's collar-bone.
Be in the habit of using your knees and thighs alone for grip, though the closer you clasp the saddle without getting your legs _around_ the horse, the better. In the leap, or with a plunging horse, you may use the upper part of the calf, or as much more as your spurs will allow you to use. But of all equestrian horrors the worst is the too common habit of constantly using the calves instead of the knees to clasp the saddle-flaps. To such an extent is this often carried by a tyro (and no man gets beyond this stage who does it), that you can see an angle of daylight between the points where his thigh and calf touch the saddle, showing that his knee, which ought to be his main and constant hold, does not touch the saddle at all. The stirrup-leathers, especially if heavy, as they should be, often hurt the knee, if you are new to the saddle, and perhaps are the main inducement to this execrable habit. But you must either get your knees hardened, or else give up the saddle. Keep a steady lookout for this. You will never ride if you don't use your knees. If you do use them properly, your feet will look after themselves. Ride with the flat of the thigh and the knee-bone at all times close to the saddle.