fixed on with one screw each, so as to allow them to be moved either to front or rear, but sufficiently tight to retain them in the position in which they are placed. A small weight is then placed exactly on the centre point of the board at p, the four legs being ad

justed square, as at x x x x. If the weight be not so heavy as to overcome the slight friction of the heads of the screws, the board will remain in its position— that is, it will stand; but if it be removed towards one end of the board, say to p1, it will cause the board to turn on the screwheads, and, if not prevented, slide down towards f; but if the two legs at this end be bent backwards to xl x1, the board will support the weight as before. In like manner, if the weight be removed in the other direction to p2, the legs being square, the same thing will occur, and the board will turn on its legs and slide down towards h, which, however may be prevented by adjusting the same pair of legs as before, and which here represent the hind legs of the horse, to the position x2x2, and in both these cases the board will assume a slanting position, in which the end a b will be lower. Or, the weight being at p2, the board may be made to stand by adjusting the other pair of legs, representing the horse's fore legs, to

the position 3 x3, and in this case it will slant the other way, the end c d being lower.

Now this is just what takes place when a rider is put on a horse's back in analogous positions, leaving out of the question for the moment the influence of the overhanging head and neck on the stability of the machine. Referring back to Plate I., we see, in fact, that the points a and d of the board correspond with the hip and shoulder joints A and D on the one side of the horse, as b and c do with the same joints on the other, and these are the two points of support of the back, whilst p corresponds with the fourteenth vertebra at E; and, still leaving the head and neck out of the question, the rider placed here would sit not only directly over the centre of motion, but also over the centre of gravity-that is to say, a central point equally removed from each of its four supporting points;* he would occupy the apex or summit of a regular pyramid, the most stable of all forms of construction.

Let us now suppose the rider, or the weight, whatever it may consist of, placed farther back towards the horse's

*It is to be remarked that the points on which the horse's feet stand seldom coincide exactly-that is, lie precisely under the shoulder and hip joints respectively. The fore feet especially seldom reach, even with the toes, the perpendiculars from the shoulderjoints. With Eclipse they did so naturally, with tolerably wellbuilt horses moderately "set up" they will generally do so; and if the setting-up is carried beyond a certain point, they not only reach but project before them, the two hind feet either following proportionately in the same direction, or going to the rear, as may be seen when the horse-dealer "stretches a horse," in order to show how much ground it covers. There is a great difference, too, between the jointed flexible legs of a horse, and the rigid straight ones represented in fig. 1. An animal always exerts a certain amount of muscular action to maintain its balance even when resting.

loins, corresponding to the point p1 of fig. 1. What does the horse do, if compelled to stand still under a burden that is more than his hind legs can easily support with perpendicular hocks? Let the reader turn to Plate VII., where the English hussar there presented shows the horse extending his hind legs precisely in the way indicated in fig. 1, x1 x1. What between the rider sitting at the hinder part of the saddle and the weight of the enormous pack, the perpendicular passing through the centre of gravity of the whole falls considerably in rear of the fourteenth vertebra. This figure is photographed from life, and is very instructive. The horse, certainly not a fair specimen of the regiment or of the cavalry in general, was selected, probably, for no other reason than because he could be easily brought to stand still during the operation; and the clearness of the lines of the original everywhere except about the head, which he probably tossed once or twice, shows that he did so, which was rendered possible, under the burden he had to bear, and the mode in which it was placed on his back, only by this very position of his hind legs; he could not stand straight under it, and the less so because his hind quarters are weaker in proportion than the forehand. The position of the head and neck has much to do with it, but this we shall have to consider further on.

The cases in which a horse, when standing still, and weighted chiefly on his forehand, assumes with his fore legs the positions indicated in fig. 1 by 3 233 or x2x2, occur so frequently that it is quite superfluous to devote a figure to their illustration. Put a man on a horse without a saddle, and with nothing but a halter on the animal's head, and he will inevitably slip for

wards till his seat comes in contact with the withers. Let him then stand still, and the horse, especially if a young or untrained one, will most probably shove forward his hind or fore legs in one of those two ways.

There remains a third case for consideration—namely, where the horse, being weighted back to the line G H, Plate I., brings his hind legs under him up to the line I K, but with the hocks bent. This is the position into which manege-horses have to be brought for certain. definite purposes, the general object being to enable them to make short turns on the hind quarters or croup, the forehand turning round this latter; whereas, with a horse weighted on the centre line E F, Plate I., the hind and fore quarters both turn equally round a common point, and with one weighted principally on the forehand, the hind quarters will turn round the former.

Now, in order to avoid drawing false conclusions from these facts, we must take another view of the question. What we have hitherto inquired into is, the effect of certain modes of distributing the weight on a horse's back when in a state of rest on the position of his legs with regard to that weight; but the really important thing to know is, how these various modes influence the horse's action. It was, however, necessary to enter into the preliminary inquiry, because most of the conditions governing a horse's attitude in a state of rest continue to be equally imperative after action has commenced, and some even more so; for it is more dangerous to the horse to lose his balance when in motion, especially at high degrees of speed, than when standing still.

We may put the questions to be resolved as follows: 1st, How does the distribution of the weight to be

carried affect the horse's speed? and, 2dly, How does action affect equilibrium or balance ?

The way in which these questions present themselves points directly to their solution; and, as regards the first, it is to the horse's legs, and the mode in which they are moved, that we must look, just as in the former case we looked to the mode in which they are fixed. There is, however, a great difference observable between the functions of the hind and fore legs when we come to compare action with rest. In the latter, we were justified in looking on both pairs equally as bearers; in the former, the fore legs are still employed chiefly as bearers, and only in a smaller degree as propellers, whereas the hind legs act chiefly as propellers and in a less degree as bearers. It should follow from this, that we may favour the propelling power of the hind legs by weighting forward within certain limits; and this we know to be the case- -the long stride of the race-horse is favoured by the well-known forward seat of the jockey. Well, what are the limits? In the case of the jockey it is difficult to draw a "hard and fast" line, because his total weight is inconsiderable, and the distances to be got over are inconsiderable; and this is precisely the reason why heavier riders, especially when they have to do long distances, should not ride forward like the jockey, because they are sure, sooner or later, to use up their horses' fore legs by making them exclusively bearers: even race-horses will break down under the light weight, and some jocks are unfortunate in this respect.

And if this be true, it is equally so that placing the weight too near the hind legs must diminish their propelling power, by converting them, in a greater degree,