belong to the initial series of movements by which a trot or a canter is changed into a gallop. The animal thus photographed was in full gallop all the time. In this position the fore leg marked I appears to bear the entire weight of the body, but, in reality, it does not (although the contrary has been maintained). The body has been propelled forwards and slightly upwards somewhat earlier, as will presently appear, and fore foot 1 is in reality scarcely supporting the body at all, but simply adding to the propulsive motion, the body needing for the moment little support.

Fig. 2 shows the horse twenty-seven inches farther forward. (It may be noticed in passing that Fig.

II shows a position of the body between the positions shown in Fig. 1 and Fig. 2.) The fore leg marked 1 has continued to propel the body forward until this leg had become so aslant (see Fig. 11) that the hoof has to leave the ground, and is thrown back as shown in

FIG. 2.

Fig 2. Fore leg 2 has been carried forward, the hoof rising and the leg becoming more sharply bent. Both hind legs have been thrown forward, but leg 4 more than leg 3, so that the hoofs are rather nearer together than in Fig. 2.

In the interval between the positions shown in Figs. 1 and 2 there had been propulsion, though not very forcibly, only one leg touching the ground, and that only during a portion of the time. As the pictures are made at equal distances of 27 inches apart, the time between Fig. 1 and Fig. 2 is to some degree diminished by the additional velocity due

FIG. 3.

to this propulsive motion. On the other hand, as all four limbs are in the air during the interval of time between Figs. 2 and 3, there has not been, in this case, any propulsive action, and the body of the horse has therefore been all the time, though but slightly, losing forward velocity. We note a considerable alteration in the position of all four limbs. Fore leg 1 has been thrown forward so far as the upper part of the limb is concerned, but the lower part of

Fore leg 2 has been thrown for-
Hind leg 3 seems, at first sight,

the limb has been thrown upward. ward and is now slightly less bent. scarcely changed in position; but, in reality, it has been thrown forward and then backward to nearly the position it had when Fig. 2 was taken. Hind leg 4 has been thrown farther forward.

Between Fig. 3 and Fig. 4 the body has been entirely in the air

until just before Fig. 4 was taken, when hind leg 3 had just touched the ground. Thus the interval in time, as there had been no propulsive motion, has been rather greater between Figs. 3 and 4 than between Figs. 2 and 3, and greater still than between Figs. 1 and 2. A correspondingly greater change has

taken place in the position of the limbs. Fore leg 1 has been curled up under the body, the upper part of the limb being thrown forward. Fore leg 2 has been thrown more markedly forward and partly unbent. Hind leg 3 has been set down by being thrown backward, and hind leg 4 has been thrown forward nearly to the farthest. In this position the body is advancing almost at its slowest-though, of course, it will be understood that in saying this I do not mean to describe the rate of advance as greatly reduced. The body has been only carried forward seven feet four inches from the position it had in Fig. 1, and its rate of advance has scarcely been reduced at all. Nevertheless, such reduction as the rate of advance does undergo during the swift gallop of the horse attains its maximum at about this position.

In Fig. 4 the fore legs have changed notably in position. Fore

leg has been thrown upward (so far as upper half is concerned) and forward. Fore leg 2 has been thrown forward in preparation for the work which this leg will have to do after the hind legs have done theirs. Of the hind legs, No. 3, which in the position of Fig. 4

FIG. St

had just begun the work of

propulsion, has driven the body well forward, so that this limb has become nearly upright. The other hind leg seems to be nearly in

the same position as in Fig. 4, but in reality it is now being carried backwards, whereas, in the former position, it was travelling forwards. This leg is the one which is next to take the work of propulsion. Notice that is the left fore leg and 2 the right. Between the work of these two legs, both hind legs do their work of propulsion: the left fore leg's work is followed by that of the right hind leg, then the left hind leg does its work and next the right fore leg.

I

FIG. 6.

In the position shown in Fig. 6 both hind legs are at work, giving to the body its strongest propulsion both forwards and upwards, but chiefly forwards. Hind leg 3 has nearly done its work; hind leg 4 has little more than begun. Fore leg has been thrown upwards and forwards, slightly unbending. Fore leg 2 has been straightened into a position which no one would imagine to be ever assumed by a horse's leg. However, one can at once see that the attitude is indicative of the energy which is about to be put into the backward stroke given by this fore limb. In considering this picture, and indeed all those in which a hoof touches the ground, it must be borne in mind that the attitude is not one assumed by the horse for any definite period of time, however short. It is difficult to dispossess oneself of the notion that this is the case, and the absurdity of some of the attitudes in our series of pictures arises chiefly from this mistaken conception. Regarding these attitudes as simply passed through during the horse's rapid rush forward in swift gallop, they no longer appear so absurd; though, even as thus viewed, there is some difficulty in imagining that attitudes so unlike those which the eye can recognise as a horse gallops past, should be assumed once in each stride. In Fig. 6 we see the horse in that part of his action which is most energetic in the galloping gait. At this stage of his stride, and at this stage only, those two legs are at work in propelling the horse forward which have the greatest propulsive power. Strictly speaking, the stride should be regarded as commenced from this attitude; and I should so have dealt with the series of pictures had it chanced that they represented precisely one stride. Since, however, Fig. 11 shows a position about a foot in advance of that shown in Fig. 1, but about as much behind that shown in Fig. 2, the series only runs by equal intervals from Fig. 1 to Fig. 11, and it was necessary therefore to commence with Fig. 1, though that really belongs to the middle of stride.

In Fig. 7 two feet are shown touching the ground, one a fore

to see how much more powerful the propulsive action of the hind legs must be than is that of the fore legs. I would venture to predict that if ever an experimental test is applied by which the propulsive action of the fore and hind legs is compared, the former will be found at least three times as effective as the latter. It will be remembered that 2 is the right fore leg and that 4 is the left hind foot. We notice, further, that the gallop is not a symmetrical gait, as the trot is. For in the trot right and left fore legs work in similar ways with left and right hind legs respectively. But we see, from the series of figures illustrating the gallop, that whereas the right fore leg works with the left hind leg, the left fore leg does not work with the right hind leg. Each of these legs-the left fore leg and the right hind leg-does its work alone, except that the right hind leg during a part of its work receives help from the other hind leg, but at no time from either fore leg. Such, at least, is the case illustrated in our series of figures; of course, the gallop can equally be executed when the right and left fore legs do the work which the left and right fore legs are here represented as doing, the hind legs also interchanging their work. In fact, the illustrations would have appeared precisely as they do if the work of the two fore legs, as of the two hind legs, had thus been interchanged. In Fig. 8 the two hind legs are both thrown back, and arc, for the moment, in a position not very unlike that in which these limbs are commonly represented in pictures of a galloping horse. But the fore limbs are posed as the fore limbs of a horse never were shown in a picture. Fore leg 2 is at work urging the

FIG. 8.

horse forward, or rather it is maintaining and increasing the

forward motion given by the energetic action of the hind legs. Fore leg I has been straightened from the position shown in Fig. 7, but it is to be noticed that in the interval between the positions shown in Figs. 7 and 8 this leg has reached its highest motion upward, and is now on its way downward. Notice also that the fore legs are always more or less bent when rising, but that as they are brought down. wards to give their stroke, they are straightened, even from the beginning of this downward motion. Compare, for instance, the pose of fore leg 2 in Figs. 5 and 6, and again of fore leg 1 in Figs. 7 and 8. Notice also that each leg remains straight in sweeping round through about a right angle, fore leg 2 from the position of Fig. 6 to that of Fig. 9, and fore leg 1 from the position of Fig. 8 to that of Fig. 11.

In Fig. 9, fore leg 2 is shown doing the last part of its work of propulsion, while fore leg is just about to begin its work.

FIG. 9.

The hind legs are so nearly in the same position in the picture that it is not easy to tell which is which. However, a little consideration will show that the leg whose hock shows highest is, as marked, fore leg 3, or the right. For, notice that in Fig. 3 the right fore leg (3) has nearly the same position as the left fore leg (4) in Fig. 5. In Fig. 4 and Fig. 6 these legs have respectively nearly the same positions. So have they in Figs. 5 and 7, in Figs. 6 and 8 though here the slight difference in time between the action of the right fore leg in one picture, and the left fore leg in the next picture but one, is shown by the right fore leg being on the ground in Fig. 6, while the left fore leg has just been lifted from the ground in Fig. 8. We infer, then, that the left fore leg in Fig. 9 has nearly the same position as the right fore leg (3) in Fig. 7-in other words, is nearly straight. Therefore, the other or more bent leg in Fig. 9 is the right fore leg (3). We see, in fact, that just as the fore legs begin to straighten just after they begin to descend for their propulsive stroke, so the fore legs continue nearly straight after their propulsive stroke, until just before they reach their greatest height. In Fig. 9, hind leg 4 is travelling backwards and passing hind leg 3, which has just begun to travel forwards, precisely as in Fig. 3 hind leg 4, travelling forwards, is passing hind leg 3 travelling backwards. The vigorous action of fore leg 2, and the vigorous attitude-preparative for