INTRODUCTORY. 



I will now give you a few short instructions in your 

 use of the instrument. Let it be inclined at a con- 

 venient angle, screw on your low-power objective, and 

 slide the eye-piece into the tube at the top of the 

 body, having previously taken care to see the lenses 



Triple-bodied Microscope. 



are free from dust; place the object you wish to 

 examine on a glass slide, and transfer it to the stage 

 of the microscope ; you will soon learn to obtain the 

 proper focus. If your object is a transparent one, 

 you must turn the mirror under the stage until a clear 

 circular light illumines the field of view; if your 

 object is opaque, you must use the condensing lens or 

 the bull's-eye condenser, and throw the light upon the 



