4A SELECTION AND USE 



fixed stage. It is hollow, and in it slides a rod which may be 

 moved up and down by means of a rack and pinion, so as to 

 adjust for focus. This rod carries a horizontal arm, into one 

 end of which the lenses fit, and the arm itself may be moved 

 back and forth across the top of the vertical rod, so as to bring 

 the lens over any part of the object. The great objection 

 to this microscope, as usually constructed, is its want of 

 steadiness, and this is a vital defect. 



The Compact Dissecting Microscope. Those who 

 desire a really serviceable and substantial microscope for dis- 

 secting purposes, will find that several manufacturers have 

 recently endeavored to supply the demand for an instrument 



Fig. 11. THE COMPACT DISSECTING AND MOUNTING MICROSCOPE. 



of this kind at a moderate price. We select one by the same 

 firm that manufactures the Excelsior Microscope the Bausch & 

 Lomb Optical Co. It is called the "Compact Dissecting and 



