CHKONOPHOTOGKAPHY ON MOVING PLATES 125 



filni itself, or at least the series of positive images 

 obtained from it by superposition on a similar strip, 

 can produce a series of effects following one another in 

 such rapid sequence that the spectator sees the move- 

 ment reproduced in all its phases. This synthetical 

 representation of movement will be described further 

 on. For ordinary publication the images are repr< >duced 

 by means of a special process called " simili-gravure." 

 Most of the figures scattered in the text were obtained 

 by this process. But as simili-gravure requires a 

 special treatment of dotting, or hatching, to give the 

 shapes of the shadows, it would be of no use for 

 reproducing very small photographs of microscopical 

 objects, nor for very graduated shading such as is 

 required for the delineation of muscles. In these 

 two cases we had recourse to impressions made with 

 lithographer's ink. When a long series of photo- 

 graphs has to be reproduced, showing the successive 

 phases of a phenomenon, plates of special size must be 

 used, or otherwise only a small number of images can 

 be obtained. If these photographs are reduced so as 

 to suit the limitations of a page, they lose much of 

 their merit and interest. This occurred in the case of 

 Fig. 87, in which eight reduced images are represented, 

 each occupying one-fourth of the space occupied in 

 the original plate. 



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