822 



HISTORY OF CHRONOPHOTOGBAPHY. 



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

 gull in flight. 



No: 6. Phofoijraph'ic (jxin, lS82.—ln the study of the flight of birds 

 the necessity of operating before a dark field or dead-black y)ack- 



FlG. S. 



ground restricts extremelj^ the number of possible experiments. In 

 order to analyze free flight it was requisite to l>e able to operate in case 

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



Fig. 9. 



aimed at a moving bird like a gun. The photographic gun (fig. 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 difl'erent 

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



