CHAPTER II 



THE COMPOUND MICROSCOPE 



Valuable as is the simple lens either for use in 

 pocket form or as a dissecting microscope, it has 

 distinct limitations, especially in magnifying power. 

 The microscopist cannot dispense with it, for obvious 

 reasons, but when it is necessary to make detailed 

 examinations of minute organisms and structures 

 a compound microscope must be used. 



The beginner will be able to gain a distinct idea 

 of the structure of a comparatively inexpensive 

 instrument from the accompanying illustration 

 (Fig. 5). The body tube (1), with the foot (5), 

 stage (7), and all the appurtenances thereof, com- 

 prise the "stand," which is a convenient structure 

 for the carriage of the lenses and the holding and 

 hghting of the object. The distance between the 

 eye-piece (13) and the objective, which fits into a 

 female thread (12) at the stage end of the tube, is 

 increased by sliding out the draw-tube (2). Rough 

 focussing is accompHshed by means of the milled 

 heads (3), by turning which the body tube is raised 

 or lowered. Fine focussing is managed by the 

 milled head (4) controlling the fine adjustment. 

 The axis joint (6) permits the worker to incline the 

 body of the instrument, along with the stage and 



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