pace. Each one has suffered himself to be guided in this respect by theoretical considerations. Those who admit equal intervals between the four footfalls, have thought that they found in this type more clearness and a more decided distinction between the amble and the trot. The other writers have attempted the realisation of a certain ideal in the kind of pace which served them as a type. For Raabe, it was the maximum of stability, which, according to his theory, is obtained when the weight of the body rests longer on the two diagonal feet than on the two lateral feet; whence arises the choice of the type represented by the notation No. 6. Lecoq, thinking, on the contrary, that the most rapid pace is the best, has chosen as his type the pace in which the body rests longer on the two lateral feet than on the diagonal ones (notation No. 4).

Whatever may be the value of these considerations, of which practical men alone can judge, it seems to us that the physiologist must first of all endeavour to search for facts, and must take simply such types as experiment may reveal to him. It is for this purpose that the investigations have been made with registering apparatus, the result of which will now be given.

APPARATUS INTENDED FOR THE STUDY OF THE MODES OF LOCOMOTION OF THE HORSE.

For the experimental shoe employed in the experiments made on man has been substituted, on the horse, a ball of indiarubber filled with horsehair, and attached to the horse's hoof by a contrivance which adapts it to the shoe.

No. 5.

Normal walking pace (Bouley, Vincent and Goiffon, Solleysel, Colin).

No. 8. Ordinary trot. (In the figure, it is supposed that the animal trots with

out leaving the ground, which occurs but rarely. The notation only takes into account the rhythm of the impacts of the feet.)

No. 9. Norman pace, from Lecoq.

No. 10. Traquenade, from Merche.

By turning an adjusting screw we fix it to the horse-shoe

FIG. 42.-Experimental apparatus to show the pressure of the horse's hoof on the ground.

by three catches, which keep the instrument securely fastened. A strong band of india-rubber passes over the apparatus (fig. 42), and keeps in its place the ball filled with horse-hair, so as to allow it to rise slightly above the lower surface of the hoof. When ⚫the foot strikes the ground, the india-rubber ball is compressed, and drives a part of the confined air into the registering instruments. When the foot is raised, the ball recovers its form, and draws again into its interior the air which the pressure had expelled. These instruments soon wear out on the road, but

will last during some time on the artificial soil of the ridingschool.

For experiments which we have made on ordinary roads, we have had recourse to an instrument represented in fig. 43.

To the leg of the horse just above the fetlock-joint is attached a kind of leather bracelet fastened by straps. In front of this bracelet, which furnishes a solid point of resistance, are placed various pieces of apparatus. There is, first, a flat box of india-rubber firmly fixed in front of the bracelet; this box communicates, by a transmission tube, with the registering apparatus. Every pressure exerted on the box moves the corresponding registering lever. It is evident that all the movements of the horse's foot are shown by pressures on the india-rubber box, and are immediately signalled by the registering levers.

For this purpose, a plate of copper, inclined about 45°, is

1

connected at its upper extremity with a kind of hinge, whilst its lower end is fastened by a solid wire to the upper face of the india-rubber box, on

which it presses by means

of a flat disc. On a wire parallel to the slip of copper slides a ball of lead, the position of which can be varied in order to increase or diminish the pressure which this jointed apparatus exerts on the

india-rubber box.

The function of this apparatus is analogous with that of the instrument represented in fig. 28, intended to show the reactions which are produced in various kinds of locomotion; only the inclination of the oscillating portions allows them to act on the membrane during the movement of the elevation, the descent, and the horizontal progress of the foot.

When the hoof meets the ground the ball has a tendency to continue its motion, and compresses with force the india-rubber box. When the foot rises,

FIG. 43.-Apparatus to give the signals of the pressure and rise of the horse's hoof.

the inertia of the ball produces in its turn a compression by a kind of mechanism already described with reference to fig. 28.

Through the kindness of Mons. Pellier, we have been able to experiment on several horses, ridden by himself, while holding in his hand the registering instruments.

When the horse had his feet furnished with the india-rubber boxes which have just been described, thick transmitting tubes not easily crushed were fitted to these receptacles. These tubes are usually fastened by flannel bands to the legs of the animal, and thence directed to a point of attachment at the level of the withers; they are then continued to the registering apparatus, which has been already described in the experiments on biped locomotion. The registrar now

FIG. 44.-This figure represents a trotting horse, furnished with the different
experimental instruments; the horseman carrying the register of the
pace. On the withers and the croup are instruments to show the re-
actions.

carries a great number of levers; he must have four at least one for each of the legs, and usually two other levers which receive their movements of re-action from the withers: and the croup. Similar kinds of apparatus to those represented in fig. 28 are employed for this purpose. The rider carries by the handle a portable registering instrument, to which all the levers give their signals at once ;. the hand which holds the reins is also ready to compress a

ball of india-rubber at the moment when the horseman wishes the tracings to commence. Fig. 44 represents the general arrangement of the apparatus at the moment when the rider is about to collect the graphic signals of any particular pace.

CHAPTER V.

EXPERIMENTS ON THE PACES OF THE HORSE.

Double aim of these experiments: determination of the movements under the physiological point of view, and of the attitudes with reference to art.

Experiments on the trot-Tracings of the pressures of the feet and of the re-actions-Notation of the trot-Piste of the trot-Representation of the trotting horse.

Experiments on the walking pace-Notation of this kind of motion; its varieties-Piste of the walking pace-Representation of a pacing horse.

THE aim of these experiments is twofold; as far as physiology is concerned, we derive from them the expression of the duration, actions, and re-actions of each pace, the energy and duration of each movement, and the rhythm of their succession. But the artist is no less interested in knowing exactly the attitude which corresponds with each movement, in order to represent it faithfully with the various poses which characterise it. All these details are furnished by the registering apparatus; the artist need fear no error if he conform his sketches to the indications furnished by the tracings made by the instrument.

The remarkable work of Vincent and Goiffon was expressly intended to establish principles relative to the faithful representation of the horse. We shall borrow some things from this book, which seems to have been too much forgotten, and not to have exercised upon art the influence that might have been expected. This is doubtless owing, in some degree, to a certain obscurity in the mode of explanation, and still more to the fact that the writers, having had recourse only to direct