THE MICROSCOPE. 



30. THUS, for example, if the tube which carries the object- 

 piece be vertical, a plane reflector, M M, fig. 1 5, receiving the ray& 



Fig. 1C. 



coming in a vertical direction from the object-piece, will reflect 

 them horizontally to the eye-piece E E. 



The same object would be attained with more advantage, and 

 less loss of light, by means of a rectangular prism, ABC, fig. 16, 



Fig. ir. 



Fig IS. 



the vertical ray, E &' being reflected by the back, A c, of the prism 

 in the horizontal direction E' R". 



Since a single reflection thus made produces an inverted image, 

 34 



