PRACTICAL MICROSCOPY, 



PAKT FIRST. 



TECHNOLOGY. 



THE LABORATORY MICROSCOPE. 



THE histologist should be provided with a microscope, in which 

 the principal features of the laboratory instrument, Fig. 1, are 

 embraced. 



The body A, which carries the optical parts, is made of two pieces 

 of brass tubing, one sliding within the other and providing for alter- 

 ations in length. The objectives, C, D, are attached to the body by 

 means of the angular carrier E. The carrier is so pivoted that either 

 objective may be turned into the optical axis, at will. The eye-piece, 

 F, slips into the upper part of the body, with but little friction, so 

 that it may be quickly and easily removed. 



The coarse or quick adjustment for focussing consists of a rack Gr, 

 which is attached to the body, and into this gears a small (concealed) 

 pinion turned by the milled-head H. 



The fine steel screw 1, by means of which the more delicate adjust- 

 ments for focussing are accomplished, terminates below in a hardened 

 point, which impinges upon one end of a lever (concealed in the arm) 

 the fulcrum of the same being indicated at the point J. The oppo- 

 site end of the lever is inserted in a notch in the split arm K. By 

 turning the milled-head L, the lever is moved, and the optical body 

 raised or lowered with extreme delicacy. 



The sfage, upon which objects are placed for examination, is per- 

 forated at M, and a rotating disc not indicated in the drawing 

 1 



