104 THE USE OF THE MICROSCOPE 



made, but the greater ease in painting conipeiisate.s foi- 

 this. Then when the whole is complete, and dry, a wash 

 with a large brush and water all over will improve the 

 evenness of the colors. 



Practical Points 



1. The Abbe camera should be raised or lowered till the eye- 

 piece circle and the opening in the silver coincide vertically. 



2. Microscope stage and desk must have the same slant. 



3. The mirror of the camera should be set at 45 degrees. 



4. Details may be put in under a binocular magnifying about 

 3 times. 



5. Line engravings are usually to be preferred to half-tones for 

 scientific drawings. 



6. The reference letters should be unobtrusive. 



7. Line drawings may be made on light photographic prints, 

 which are afterwards bleached by iodine solution and 

 hyposulphite. 



8. The magnification of the drawing may well be marked by 

 projecting the virtual image of the scale of an object micrometer 

 with the same camera on it. This has the advantage over stating 

 the numerical magnification, that it is not made erroneous by 

 enlargement or reduction of the drawing. 



