STUDENTS HISTOLOGY 



FIG. 1. THE MICROSCOPE. 



The whole is supported on a short, stout pillar rising from the 

 base, O. 



LENSES OF THE MICROSCOPE 



Fig. 2 shows the arrangement of lenses, including a high- 

 power objective. 



The objective, A, is provided with one simple and two compound 

 lenses. The lens, B, nearest the object, and the one upon which 

 the magnifying power mainly depends, is a hemisphere of crown 

 glass. A lens of such form possesses both chromatic and spherical 

 aberration in high degree. These faults are corrected by the com- 

 pound flint and crown lenses, C and D, placed above the hemi- 

 spherical glass. 



The eye -piece consists of two crown glass, plano-convex lenses, 



