142 NOTATION OF THE PACES OF THE HORSE. 



CHAPTER XIV. 



NOTATION OF THE PACES OF THE HORSE. 



That distinguished French savant, M. Marey, published in 1878 his re- 

 searches on the paces of the horse. He prosecuted them by means of a 

 registering apparatus somewhat similar to the one, the sphygmograph, used by 

 doctors for recording the movements of the pulse. The machine consisted of 

 a cylinder which was made to revolve round by clockwork. Attached to it 

 were four pointed levers that were arranged so as, when pressed upon, to 

 trace lines on a piece of blackened paper. Each of these levers was 

 provided with an India-rubber tube, which communicated with a rubber ball 

 filled with air and fixed on the ground surface of one of the animal's feet. 

 These levers and their connections were made so that, when the horse 

 during movement put a foot on the ground, the rubber ball attached to that 

 particular foot would be compressed, and the air rushing into the tube would 

 raise the lever and bring its point against the sheet of blackened paper. 

 When the animal lifted its foot from the ground, the air would go back into 

 the ball, and allow the point of the lever to be taken off the surface of the 

 paper. As, while this was being done, the cylinder revolved round at a 

 uniform rate of speed, it follows that the line traced by each lever point 

 would be a record of the duration of the contact of the foot with the ground, 

 and that the intervals between two such contacts would be a measure of the 

 time the foot was suspended in the air. By this means, M. Marey 

 investigated the nature of the paces of the horse. He also devised a very 

 ingenious method of representing them on paper, which I shall now try to 

 explain to my readers. 



If we wish to express on paper the running pace of a man, we may do so 

 by making a scale with rectangles, which, for convenience sake, we may use 

 instead of M. Marey's lines. Thus, if the time of contact be about equal to 

 that of suspension, Fig. 154 will express the nature of the pace. To render 



