THE PHOTO-MICEOGBAPHIC CAMEEA 145 



operator may make sure of the absence of glare, which is 

 particularly disturbing in photographic work, by removing 

 the object and replacing it by a non-reflecting body, preferably 

 black velvet. The field, as seen through the eye-piece, should 

 then be black. 



After a little practice this test will become superfluous, since 

 slight glare will be readily recognised in the course of the 

 manipulations described. 



Having secured the proper adjustment, as controlled 

 through the eye-piece tube, put the latter out of action and let 

 the image appear on the ground-glass focussing-screen. Photo- 

 graphs are taken by this apparatus with the aid of an eye-piece 

 as well as the objective, a fitting containing an eye-piece being 

 inserted into the sleeve attached to the camera. The final 

 focussing and the adjustment of the carbons is effected with the 

 aid of the transmission gears F 1 and F 2 (Fig. 53). 



The image, as seen in the observing eye-piece or on the 

 ground-glass screen, should be evenly illuminated, bright, and 

 undistorted. The presence of distortions should be regarded as 

 an indication that prisms P and P 1 are not properly adjusted. 



