344 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



FlGUBE 1. Diagram of PnoTOGRAPnic APPARATUS. (', natural size) 



A, sensitive plate or film holder 

 I'., box containing Bhutter. 



C, pulley attached to axle of Bhutter to communicate power from motor. 

 I), light r- »<l moved by crank attached to Bameaxle; D is guided by a stout 

 support in which it moves loosely. 



E, segment provided with ratchet-teeth; moved gradually by rod D. 



F. microsc >pe 



'. slide for object, moved by wire running to II 



II, holes to n amplitude of object's motioa 



I, weight, balancing segment. 



J, horizontal projection of revolving shutter in detail. 



Tin- diagram represents the apparatus an Instant before an exposure begins 



