THE MICROSCOPE. 
30. Thus, for example, if the tube which carries the object- 
piece be vertical, a plane reflector, M M, fig. 15, receiving the rays 
Fig. 15. 
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,. 
A 
the vertical ray, e e' being reflected by the back, a c, of the prism 
in the horizontal direction e' e". 
Since a single reflection thus made produces an inverted image, 
34 
