120 NOTATION OF THE PACES OF THE HORSE. 



NOTATION OF THE PACES OF THE HORSE. 



That distinguished French savant, M. Marey, published in 1S78 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 leveis that were airanged 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 rushmg 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 cylmder 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, 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 tiy 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 Marey's lines. Thus, if the time of contact be about equal to 

 that of suspension, Fig. 212 will express the nature of the pace. To render 

 this figure more graphic, I have used plain rectangles to mark the supports 

 of the left foot, and shaded ones, those of the right foot If we desire to 

 represent the ordinary walk of a man in the same manner, we shall be con- 

 fronted with the difficulty that, as both feet are on the ground at certain 

 periods of this pace, the rectangles would naturally have to overlap each 

 other. We may, however, get over it by placing the diagrammatic prints of, 

 say, the left foot on a line above those of the right foot. In this manner, in 



