302 



TROUBLES WITH MICRO-PROJECTION 



1G 



[CH. IX 



FIG. 167. UNIVERSAL PROJECTOSCOPE SHOWING THE ARRANGEMENT 

 FOR HORIZONTAL TRANSPARENCIES AND FOR MICROSCOPIC PROJECTION. 



(Cut loaned by the C. H. Stoelting Co.}. 

 Commencing at the left : 



1 Feeding screws for the carbons. 



2 Fine adjustment for moving the arc lamp back and forth along the axis. 

 3-4 Fine adjustment screws for moving the arc vertically and laterally to 



keep the crater in the axis. 

 L H Lamp and lamp-house. 

 C First element of the two-lens condenser. 

 F-F vSupports. 

 T Water-cell. 



M Mirror above the objective to reflect the light to the vertical screen. 

 M, M, Mirror in position to reflect the horizontal beam directly upward. 

 C, C 3 Second element of the two-lens condenser. 

 R Projection microscope. 



B Optical bench on which slide the different pieces of apparatus. 

 B l B, Supports of the optical bench. (See also fig. 16, 102). 



2. The object may not be in the best position in the light cone 



3. The substagc condenser, when that is used, may be a little 

 too near or too far from the specimen. Slight changes in 



