LOCOMOTION OF QUADRUPEDS 



207 



of its movements from a physiological or mechanical 

 aspect. We have applied the method of geometrical 

 chrono-photography to the study of equine paces, so as 

 to obtain a large number of photographs on a fixed plate 

 in series, and to show the movements of each of the 

 segments of the limbs ; in fact, just as we did in the 

 case of human movements. It would be very difficult 

 to cover a horse with black velvet, and to arrange on it 

 black spots and lines marking the different joints and 

 the various axes of the long bones. We, therefore, 



Fig. 146. — Frieze at the Parthenon. Horse at a canter. 



chose an animal with a dark coat, and in places we 

 deepened the colour by painting it with lamp-black. 

 Then, on the principal joints, we fixed little pieces of 

 white paper, the shape being different for each joint — 

 one square, another triangular, another straight, and 

 another circular, and so on (Fig. 147). The animal was 

 then made to pass in front of a dark screen, and a 

 series of trajectories of the joints was thus obtained. 

 In the enlarged photograph, the different joints had to 

 be connected by lines, so as to indicate the positions of 



