LATEST FORMS OF ABBE'S CAMERA LUCID A 283 



image must not to any serious extent be weakened by the light from 

 the drawing material. (2) The image of the drawing paper must 



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FIG. 222. Latest modification of Abbe's camera 



reach the eye with the least possible intensity and be coaxial with the 

 microscopic image. (3) There should be an arrangement by which 



FIG. 223. 



the relation of the intensities of these two images can be modified 

 to suit each other. (4) The apparatus must be adjustable in height 



