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HISTORY OF OHRONOPHOTOGRAPHY. 



each to the next, and representing the successive attitudes of a sea- 

 gull in flight. 



No. 6. Photographic gun, 1882. — In the study of the flight of birds 

 the necessity of operating before a dark field or dead-black back- 



ground restricts extremely the number of possible experiments, in 

 order to analyze free flight it was requisite to be able to operate in case 

 of need on the bright sk} T and to arrange an apparatus capable of being 



aimed at a moving bird like a gun. The photographic gun (tig. 8) con- 

 tains in its barrel a long-focus objective. In its breech there turns a 

 circular plate, which presents to the focus of the objective different 

 points of its border. In short the apparatus is analogous to the astro- 





