CHRONOPHOTOGRAPHY ON FIXED PLATES 65 



is false, because a variety of attitudes on the same 

 spot are reproduced in the photograph as if they 

 were onward movements. The real position of each 

 movement must be located in the diagram. This can 

 be done in the following way : — By the side of a man 

 jumping about on the same spot, or walking slowly, 

 a white and perfectly motionless object is placed just 

 in front of the dark background. The images of this 

 object will be arranged in a consecutive series on the 



Fig. 44.— Rotating mirror for separating the images of an object which moves too 



slowly. 



plate. Xow, as it is known that these positions corre- 

 spond to a fixed point, they serve as a means of 

 estimating the real positions occupied by the man at 

 the time of each exposure. Such a movement im- 

 parted to the apparatus is a very simple means of 

 obtaining a consecutive series of chronophotographic 



