236 



MOVEMENT 



recourse must be had to chronophotography on moving 

 films. By making use of a dark background we have 

 obtained as many as 60 distinct images per second. 

 Fig. 165 is an example of this kind ; the film is cut 

 into six pieces, which are placed side by side in the 

 illustration. The images are numbered in ordinary 

 the order in which they were 



figures, according to 

 taken. 



Simultaneous Photographs of the Same Bird taken 



Fig. 166.— Arrangement of the three dark backgrounds and the three cameras for 

 simultaneous photograph y of a flying bird, as seen from three points of view. 



from Different Aspects. — If we want to analyze the 

 movements of flight with extreme exactness, the bird 

 must be photographed from several points of view. 

 Three cameras are usually required for this purpose, 

 as well as three dark screens against which the object 

 is clearly visible. The arrangement is represented 

 in Fig. 166. 



