114 MOVEMENT 



by the resistance of the air, as is shown in Fig. 79 ; 

 but in the majority of cases the images are too small 

 to stand enlargement. 



To obtain larger images, certain authors, among 

 others, M. Loncle and General Sebert, have constructed 

 an apparatus furnished with multiple objectives, the 

 shutters of which open in succession. But such a 



Fig. 78. — Photograph of a gull during flight. Reproduction by means of Heliogravure 

 of a cliche obtained by means of the photographic gun. 



multiplication of objectives is productive of serious 

 difficulties. Besides making the instrument very 

 costly, especially if objectives of good quality are 

 used, photographs are produced which, taken from 

 different points of view, are incapable of comparison. 

 This is not the case with photographs of small 

 dimensions taken at a short distance. These cameras 



