MOVING PICTURE FILM AND MECHANISM [Cn. XI 



arrangements employed in the different makes of machine, the 

 principle is simple, although the mechanical problems in work- 

 ing out these principles require much care. 



Objective 



FIG. 231. FIGURE TO REPRESENT THE PRiNciPLE7oF THE MOVING 



PICTURE MACHINE MECHANISM. " 

 a b Sprocket wheels moving with uniform velocity. 



c Intermittent sprocket wheel which jerks down the^short section^of film 

 between L and M. 



i Idlers to hold the film on the sprocket wheels. 



D Gate which holds the film in place in front of the aperture plate. 



F Upper film reel, unwinding. 



G Lower film reel, winding up. 



S Aperture plate. 



Objective. 



