416 



Transactions of the Society. 



A column of the denominators m — t — O.I. is given 

 course 4370 throughout the table. 



10 v is of 



Objective. 



Apochromatic 



„ ■ • . . 



Achromatic 



Apochromatic 



>» 



»> 



„ . . . . 

 Achromatic 



h • • 



Apochromatic 



>» 



ii 



,, • • . . . • 



„ without screen 



n . . . . • • 



Achromatic 



» 



Apochromatic 



» 



» ■ • * • 



Achromatic 



,, . . . . . . 



Semi-apochromatic * . . 



,, .... 



i» .... 



Achromatic 



is 



Semi-apochromatic * . . 



Achromatic ' 



* Short-tube objectives. 



