GENERALITIES OF THE GAITS. 



489 



different attitude and in another place of the space ; this second image, compared to the first, would 

 indicate exactly all the displacements which were effected at this second instant. By increasing 

 thus the images at very short intervals of time, we would obtain, with perfect accuracy, the suc- 

 cession of the phases of locomotion. Now, in order to preserve in the photographic glass plate the 



FIG. 181. Chrono-photograph of the walk of a man. (M. Marey.) 



sensibility necessary to receive the successive impressions, the space in front of the apparatus 

 must be absolutely dark and the man or the animal passing before it must stand out in white 

 upon a black ground. 



FIG. 182. Chrono-photograph of the leap of a man. (M. Marey.) 



" My screen is a cavity whose walls are black. A man entirely clothed in white, with the 

 light of the sun shining brightly upon him, passes, walking, running [Fig. 181], or leaping [Fig. 

 182J. while the photographic apparatus, provided with an oval window rotating more or less 

 rapidly, takes his image at more or less close intervals." 



" This method can be applied to the study of the different types of locomo- 

 tion ; a white horse or a white bird will in the same manner give the series of 

 their attitudes." 



This process has been recently attempted upon the horse by Messrs. Marey 

 and Pages. 1 



1 Marey et Pages, Mouvement du membre pelvien chez 1'homme, l'e"16phant et le cheval, in 

 Comptes-Rendus de 1'Academie des sciences, 18 Juillet, 1887. 



