Using the Microscope 



287 



that they require frequent adjustment. The Nernst light is a good 

 source of illumination, but, after repeated trials, we have laid it 

 aside because it is always getting out of order. 



Optical companies are now making very small incandescents with 

 reflector, ground glass, and filter which promise to be satisfactory 

 for most work. 



FIG. 106. A satisfactory artificial light 



We are still using the globes and find such light not only equal 

 to the best daylight, but in many cases superior. 



When using the camera lucida, it is necessary to have a mirror 

 placed so as to throw a fairly strong light upon the paper and the 

 pencil point. A piece of silvered glass 3 or 4 inches square is large 

 enough. Such a mirror can be held by an ordinary ring stand, as 

 shown in Figs. 105 and 106. 



