THE MICROSCOPE. 



45 



rendering the paper less brilliant, and thus enabling the eye 

 better to see the reflected image. The lens L below the reflector 

 is to cause the light from the paper and pencil 

 to diverge from the same distance as that re- 

 ceived from the eye-glass; in other words, to 

 cause it to reach the eye in parallel lines. 



Dr. Wollaston's camera lucida, as shown in 

 Fig. 24, is sometimes attached to the eye-piece 

 of the microscope for the same purpose. In 

 this instrument the rays suffer two internal re- 

 flections within the glass prism, as will be seen 

 explained in the article " Camera Lucida." In 

 this minute figure we have omitted to trace the reflected rays, 

 merely to avoid confusion. 



Annexed are four engravings of microscopic objects, the true 

 character of which it is, however, impossible to give in wood, and 

 is difficult indeed to accomplish by any description of engraving. 



Fig. 



Fig. 25. 



Fig. 26. 



Fig. 27. 



