GENERALITIES OF THE GAITS. 



499 



reserved for a certain number of cards, upon which are written all the indications for the rapid 

 construction of the trail of eacli gait. 



The anterior face of the board contains forty-five lines, indicated by numbers along the 

 edges. Finally, upon the middle of this face also exist two vertical series of hooks, DE, FG, the 

 one indicating the trail of the left feet, the other that of the right. The shoes, whose light color 

 contrasts with the black ground of the board, are hung on these hooks. We will compose the 

 trail of the amble, for example. From the middle drawer is selected the memorandum card 

 of the gait upon which the necessary instructions are given, as follows: 



ORDINARY AMBLE. 



It suffices to hang each shoe to the number indicated in order to obtain immediately the 

 desired trail. 



4th. Artificial Reproduction of the Locomotory Movements ; 

 Animators for Instantaneous Photographs or Draw^ing-s taken from 

 them. — Physiology teaches that the impressions received by the retina last for 

 some instants after the luminous body which has produced them has disappeared. 

 It is thus that the rapid displacement of an incandescent coal apj)ears to the 

 eye in the form of a stream of fire ; the descent of a rain-drop, under that of 

 streaks passing from the clouds to the earth, etc. 



Basing his observations upon this fact. Plateau, in 1832, constructed an 

 apparatus, the phenakislicnpc, in which are placed a series of pictures, each rep- 

 resenting a special phase of a determined movement, the gallop of a horse, for 

 example. A proper rotation being given to these images, there will be repro- 

 duced with surprising exactness the complete movements of which we have, in 

 reality, only the different periods. 



The zootrope is an instrument based upon the .same principle. It is com- 

 posed of a cylindrical box, in the interior of which is a strip of paper with the 

 portraits of an animal in different positions of his gait. A certain number of 

 vertical openings or windows expose the interior of the box and allow the 

 observer to view the series of images on the inside. The whole pivots on a ver- 

 tical axis and can be rotated at will more or less rapidly. 



It is with the zootrope that we can demonstrate the absolute truth of the 

 instantaneous photographs. It is even possible to render the movements result- 

 ing from the succession of these images tangible to a whole audience, as we have 

 witnessed with M. Marey, by placing the animator in front of an apparatus on 

 which the images are projected. The effect is then complete : the displacements 

 of the neck, the head, the members, the tail, the inflection of the body,— all, 

 even the movements of the jockey, give to the spectator the sense of reality. 



5th. Schematic Fig-ures of M. Mathias Duval.— Knowing, as we will 

 verify farther on, that the differences existing between the gaits are associated 

 with a more or less marked quickness of the movements of the posterior members 

 in relation with those of the anterior. Professor Mathias Duval has conceived 

 the idea of reproducing a gait in all its details, by constructing a series of designs 

 capable of gliding one upon the other, and thus realizing the quickness in question. 



