68 SELECTION AND USB 



calm view of the actual results which have been attained, there 

 is little room for doubting that the wide angles have gained the 

 victory in all the most important points. In a subsequent 

 section we shall give our view in regard to the circumstances 



Fig. 14. 



Fig. 15. 



DR. GORING'S FIGURES ILLUSTRATING ANGULAR APERTURE. 



which ought to influence the beginner in the selection of ob- 

 jectives of high or low angles ; at present we shall confine our- 

 selves to a discussion of what angular aperture is, and its 

 influence upon the working qualities of the objective. 



The reader who will carefully look over the pages of the 

 microscopic journals published during the last few years, will 



