THE GAITS IN PARTICULAR. 



515 



ciated by most authors who only had recourse to direct observation. 

 The means of investigation employed by M. Marey has enabled him to 

 harmonize these views. Having established this divergence of opinion by 

 citing H. Bouley, 1 according to whom the period of projection is shorter 

 than that of the contact, contrary to Raabe, 2 who claims the reverse, 

 this learned experimenter expressed himself in the following terms : 3 



" An old and very docile horse has furnished the tracing repre- 

 sented in Fig. 209. In this figure are indicated the tracings of the 



FIG. 209. Tracing, notation, and reactions of the trot. 



AG, beginning of the contact of the anterior 



left foot. 

 AD, beginning of the contact of the anterior 



right foot. 



PD, beginning of the contact of the posterior 



right foot. 

 PG, beginning of the contact of the posterior 



left foot. 



contact with the soil of the four members, with their notation, and, 

 besides, the reactions given by this gait to the horse. . 



" Here it is observed that the curves of the contacts of the four 

 feet reach two different levels : the higher are the curves of the ante- 

 rior members ; the lower, those of the posterior. In each of these 

 series the curves of the left foot are represented by dotted lines ; those 

 of the right by the continuous lines. 



" The ascent of each curve expresses the commencement of the 

 contact of the foot upon the ground ; the descent indicates the moment 

 when the foot is raised. 4 It is seen, from these tracings, that the feet 



1 H. Bouley, loc. cit., t. i. p. 391. 



2 Raabe, Locomotion du cheval (Examen des allures), p. 39. 



3 Marey, La machine animale, p. 150. 



4 " The duration of the contact should be indicated by a horizontal line, but we have given 

 to the tube a narrowness destined to weaken the sudden impulse impressed upon the registering 



