82 PHOTOMICROGRAPHY 



(ii) 2", ", 4", or -^" oil-immersion, with x4 and x8 

 eyepieces. 



(iii) In cases where the higher powers? are most fre- 

 quently used, I", J", and T V" oil-immersion, with x 4 and 

 X 8 eyepieces. 



(iv) If only two are bought, a great deal can be done 

 with 1" and |" with x4 and x8 eyepieces. 



