58 



MOVEMENT 



the number of images has to be very limited, for the 

 length of each, measured in the direction of movement, 

 is so great that they readily overlap, as in Fig. 38. 



Fig. 38.— Arab horse at a gallop. The large surface covered by e. «.h image cause 

 almo.it complete superposition. 



Influence of the Rate of Movement. — In different 

 speeds of translation, the number of images which can 

 be taken in a given time without producing confusion, 

 increases as the former become greater. This may 

 be proved by comparing a series of images of a runner 

 (Fig. 39) with those of a man merely walking (Fig. 37). 



FlG. o9. - A man ruimuig. Uuiunop.iutogrupliy on ;i fixed plate. 



The figures of the runner are much further apart, 

 although the frequency of exposure is the same in both 

 cases. If the runner were to come to a standstill, the 

 images would become superimposed. Sometimes such 



