16 HOW TO USE THE MICROSCOPE 



mirror (10), which, in its gimbal (11), is inchned at 

 any angle. Beneath the stage is a substage collar 

 (9), into which a hght condenser, a spot lens, or 

 polariscope, may be slipped. The stage, it will be 

 noted, has a circular opening, ia order that hght 

 may reach the object from beneath. 



The stand figured embodies all the essential 

 features of a compound microscope. More ela- 

 borate stands in great variety, providing numerous 

 conveniences, are obtainable at considerable cost, 

 but the less costly stand described is equal to all 

 the demands that an amateur worker is hkely to 

 make upon it. 



A handy youth, possessed of more iagenuity than 

 cash, and desiring to have a microscope, need ex- 

 perience httle difficulty in making one for himself. 

 When the author was a boy he made one with which 

 he did a good deal of work, and from which he 

 extracted much pleasure. Of course, it had many 

 faults, but it served when money for a good instru- 

 ment was not available. The body tube was made 

 by rolhng glued black paper round a portion of a 

 broom-stick. When the glue had set, the tube was 

 removed from the stick and cut to a 10-inch length. 

 I had two objectives, one consisting of a small 

 double convex lens set in a home-made tube 1 inch 

 long, and made to sUp in the body tube ; and the 

 other of two double convex lenses, fixed one at 

 each end of an inch tube, shpping into the body in 

 similar fashion. In each objective there was a 

 Umiting diaphragm in the form of a metal " washer " 

 with an aperture of about ^ inch. The diaphragms 

 served to cut off objectionable light rays, and thus 



