12 ELEMENTS OF APPLIED MICROSCOPY. 



piece forms an erect and virtual image, A^B^, of the real 

 inverted image A ^B^. 



g. Defects of the Compound Microscopes. — ^The com- 



FiG. lo. — Hooke's Compound Microscope (1665). 

 (After Carpenter-Dallinger.) 



pound microscope was at first of little practical impor- 

 tance, on account of the complications introduced by 

 spherical and chromatic aberration. The former is due 

 to the fact that the rays which pass through the outer 



