THE MICROSCOPE 



31 



Aplanatic lenses are those which have been corrected 

 for spherical aberration. 



THE SIMPLE MICROSCOPE 



The simple microscope or magnifying glass consists 

 of a double convex lens or a combination of such 

 lenses. The image produced appears erect, or right 

 side up, and is a virtual magnification. 

 The object is placed within the focal 

 point of the lens (Fig. 12). While the 

 field or area which can be magnified 

 by a simple microscope is nearly as 

 large as the diameter of the lens, the 

 outer edges will show spherical and 

 chromatic aberration unless the con- 

 struction is such as to correct these 

 faults. The magnification is com- 

 paratively low and seldom exceeds 25 diameters. 

 The forms of simple microscopes range from the 



Fig. 15. — Jewel- 

 er's Magnifier 

 or Simple Micro- 

 scope. 



(Bausch & Lomb.) 



Fig. 16, — Simple Dissecting Microscope. 

 (Bausch & Lomb.) 



jeweler's magnifying glass or loup (Fig. 15), to com- 

 plex instruments fitted with achromatic and aplanatic 



