24 THE MICROSCOPIST. 



confusion of vision. This may be partly remedied by a 

 small hole or stop behind the object-glass, which reduces 

 the aperture to the central rays alone, yet it is still un- 



FIG. 2. 



Compound Microscope. 



satisfactory. Some considerable improvement may result 

 from using Wollaston's doublet as an object-glass, but the 



