The Abbe Diffraction Theory. By J. W. Gordon. 391 



Proceeding in this way, I have deduced the two following figures 

 for the resulting antipoint in the two contrasted cases, in which 



Fig. 91. 



{1) the objective has a large effective back lens and low magnifying 

 power — (fig. 91) ; and (2) the objective has small effective back lens 

 aperture and high magnifying power — (fig. 92). It is evident that 



Fig. 'J2 



•widely different geometrical figures would result from plotting down 

 the pattern of the diatom with antipoints so very different as these in 



