

GENERAL INTRODUCTION. 



I. THE MICROSCOPE AND ITS USE. 



The microscope * consists of a stand, a tube, and 

 lenses. Attached to the column of the stand is a 

 horizontal plate, the stage, which holds the object 

 to be examined. 



In the middle of the stage is a round hole 

 through which light can be directed upward by a 

 mirror which is attached to the stand below the 

 stage. The amount of light can be regulated by 

 diaphragms. 



The stand gives support above the stage to a 

 vertical cylinder in which the tube slides up and 

 down. 



The combination of lenses to be inserted into 

 the upper end of the tube is the eyepiece (or ocu- 

 lar) ; that at the lower end the objective. 



The objective AA is a low power, D is a high 

 power. 



Objective AA, eyepiece 2 magnifies about 50 

 diameters. 



Objective AA, eyepiece 4 magnifies about 90 

 diameters. 



* The description applies to the Zeiss microscope, Stativ VII, 

 with oculars 2 and 4, objectives AA and D. 



