THE PACES OF THE HORSE. 



131 



represented by similar signs placed exactly over each other. In the 

 horse, this agreement between the movements of the fore and hind 

 limbs belongs to the amble, and the notation is the same as would 

 be given by that pace. In the amble, the ear perceives only two 

 beats at each pace, the two limbs on the same side striking the 

 ground at the same instant. In the notation, these two sounds are 

 marked by vertical lines joining the two synchronous impacts. In 

 the amble, the pressure of the body on the ground is said to be lat- 

 eral, as the two limbs on one side only are in contact with the ground 

 at the same time. 



The rhythms of both the walk and the trot have been similarly 

 ascertained and expressed, but beyond this the unaided senses have 

 failed to give us much trustworthy information. It has been reserved 

 for M. Marey to surmount the difficulties of the investigation ; and we 

 will now give, though necessarily in an imperfect way, some account 

 of his methods and results. 



For the shoe employed in the experiments on man, M. Marey sub- 

 stitutes, in the case of the horse, a ^ 

 ball of India-rubber filled with horse- 

 hair, and attached to the shoe on the 

 under-side of the hoof. The contriv- 

 ance is shown in Fig. 2. A strong 

 band of India-rubber passes over the 

 apparatus and keeps in its place the 

 ball filled with horse-hair, allowing it 

 to rise slightly above the lower surface 

 of the shoe. When the foot strikes 

 the ground, the ball is compressed, 

 which drives a part of the confined 

 air into the registering instruments. 

 As the foot is raised the ball recov- 

 ers its form, and again fills with air, 

 to be expelled at the next impact of 

 the foot on the ground. Another form 

 of apparatus, serving substantially the 

 same purpose, and better adapted to 

 ordinary roads, is seen in Fig. 3. This 

 consists of a kind of leather bi'acelet 

 fastened by straps to the leg of the 

 horse just above the fetlock-joint. In 

 front of this bracelet, which furnishes 

 a solid point of resistance, is firmly 

 fixed a flat box of India-rubber; this 

 box communicates by a transmission- 

 tube with the registering apparatus. Every pressure exerted on the 

 box moves the corresponding registering-lever. A plate of copper, 



Pig. 3. Apparatus to give the Signals 

 op the Pressure and Rise op the 

 Horse's Hoop. 



