208 



XVI. THE STEM APEX. 



The light from the mirror of a simple microscope is often too 

 strong for convenient observation, and it may be an advantage to 

 cover the mirror with a piece of highly-glazed white paper. 



OC 



W 



FIG. 81. Large dissecting microscope (Zeiss), half natural size, ot, stage ; p, wings 

 as arm rests ; sr, screw-head for adjustment ; I, system of lenses, of which ob is the 

 objective, oc, the eye-piece. Upon the stage is an object-slide fixed with the clips. 



ground, such as a white or black tile, and fixing in the eye a watchmaker's 

 glass. These can be obtained in cork frames, very light and easy to grasp 

 with the facial muscles ; or a good lens may be supported upon a stick set 

 into a weighted foot. 



An excellent method of dissection or of manipulation, provided one does 

 not wish to magnify to more than a limited extent, is to have a pair of 

 spectacle frames made, with round hoops, into which can be inserted two of 

 the watchmaker's glasses with aluminium, cork, horn or wood frames. 

 These can be made with lenses of different strengths, and, with a very little 

 practice, perform yeoman's service. [ED.] 



