CHRONOPHOTOGKAPHY ON MOVING PLATES 105 



of the planet during the period of transit, and each was 

 separated from its neighbour by an interval of seventy 

 seconds. In this photograph the dark silhouette of 

 the planet stood out in strong contrast against the 

 white background formed by the sun's surface. In 

 the first of the series the disc representing the 

 planet projected beyond the solar lirubus, but in the 

 third coincided with it. Mr. Janssen made the further 

 suggestion of applying a photographic series to the 

 study of animal locomotion.* 



It remained fur Mr. Muybridge, of San Francisco, to 

 discover, by means of a rather different method to that 

 of Janssen, the analysis of equine locomotion, as well 

 as that of man and various animals. 



Muybridge's Method and Apparatus — Mr. Stanford, 

 formerly Governor of California, believed that the 

 various positions of a horse in executing its different 

 paces could be reproduced by means of photography, 



* This is bow our colleague expressed himself in 1878: — "The 

 characteristic of the revolver is that it affords an automatic means of 

 taking a series of photographs of the most variable and rapid pheno- 

 mena in a sequence as rapid as may be desired, and thus opens up 

 for investigation some of the must interesting problems in the 

 physiology and mechanics of walking, flying, and various other 

 auimal movements. 



" A series of photographs of any particular movement, comprising 

 the entire cycle of events, would be a most valuable means of elucida- 

 ting the mechanism involved. In view of our present ignorance on 

 the subject, one could imagine the interest of possessing a series of 

 photographs representing tne successive positions of a bird's wing 

 during the act of Might. The principal difficulty would arise from 

 the sluggishness of our photographic plates, for images of this kind 

 reqnire the very shortest exposure. But, doubtless, science will over- 

 come difficulties of this kind. 



"From another point of view, the revolver may be said to present 

 the reverse picture to that of the phenakistoscope. 31. Plate.iu's 

 phenakistoscope is designed for the purpose of reproducing the effect 

 of a movement, or of an action, by means of a serit s of views, which 

 represent the component phases of the movement or action. The 

 photographic revolver gives, on the contrary, an analytical repro- 

 duction of the movement by representing in series its elementary 

 phases." — Bulletin de la Sociele Francaise cle Photoqraphie, Dec!, 

 1876. 



