Fig. 123.—Notation of the Ambling Gait in the Horse (after Professor Marey).
Professor Marey has studied these paces by a similar method to that which he adopted for the walking of man, and which we have already described. He employed hollow balls fixed under the hoofs, and a registering apparatus with four styles, each corresponding to one of the limbs. The tracing obtained is rather complicated, since two sets of lines are found marked. But a notation similar to that of which we have spoken can be discovered, and its exact signification should now be determined. For this purpose, we have selected the most simple (see [Fig. 123]). We there see, placed in two superimposed lines, the pressure markings of the right feet (white bands), and of the left feet (gray bands). On the upper line are found those related to the fore-legs; the lower lines contain those associated with the hind-legs. It is, in brief, the superposition of two notations of the human walking movements. And seeing that, as we have previously pointed out, we may make a comparison between a quadruped and two men placed one behind the other, it is easy to understand the significance of the superimposed notations, if we accustom ourselves to look on them as the notations of two bipeds.
To read these notations—that is, to learn to know what occurs at each of the movements of the pace—it is necessary, indeed, to remember that they should be examined in vertical sections; it is to each of these sections—of these vertical divisions—that each of the movements which we more particularly wish to analyze corresponds.
We proceed to study first the pace of ambling, because it is the most simple; we shall then consider the trot, and, finally, we shall examine that which is the most complicated, viz., the step.
The Amble.—To give an exact idea of the general character of the amble, let us fancy the two men whom we discussed above marching one behind the other and walking in step—that is, moving the legs of the same side simultaneously. They will thus represent the amble, which, indeed, results from the alternate displacements of the lateral bipeds; the limbs of the same side (right or left) execute the same movements in the same time.
This is what the notation indicates ([Fig. 123]). We there see that the pressures of the right fore-foot, marked by the white bands in the upper range, are exactly superposed on those of the right hind one, which are marked by a similar band on the lower line; this means that the pressures took place in the same time. We there see also a similar arrangement of the gray bands, which has a similar significance for the left fore and hind feet.
