294 



VI. — On a Modified Form of the Lever Fine-adjustment, and a 

 simple Turn-out Device for the Suh-stage Condenser ; with 

 a Note on the use of the Bertrand Lens. 



By E. B. Stringer. 



(Eeod April 17, 1912.) 



The principal objection to the usual form of lever fine-adjustment 

 appears to be that the lever bears upon the movement from below, 



Fig. 53 



pushing it up against an opposing spring situated at the top. 

 Lateral movement is tlius very likely to be set up. The object of 



