THE MICROSCOPE. 



9 



The nose-piece is attached to the lower end of the body and bears 

 the objectives. 



The objective is the lens attached to the body or nose-piece. It 

 often consists of several pieces of glass cemented together. 



The objectives commonly used are the two-thirds, one-sixth, and 

 one-twelfth inch. By a two-thirds inch objective is meant one whose 

 magnifying power is equal to that of a lens whose focal length is 

 two-thirds of an inch. 



The eye-piece comprises the lenses which fit into the upper end 

 of the draw-tube. It contains a field-glass and eye-glass, each a 

 piano convex lens, with the convex surface downward. 



The coarse-adjustment consists of the two vertical milled-heads 

 and the rack and pinion. 



The fine-adjustment is secured by the horizontal milled-head. 



Laboratory exercise No. 1. Examine a compound microscope and 

 make out each part named above. Make a study of the diagram on page 

 10. 



Substage Attachment with. Condenser. 



Bausch k Lomb Optical Co., Rochester, N. Y. 



