CH. VIII] 



THE POLARISCOPE IN MICROSCOPY 



265 



parallel, i.e. when the faces through which the oblique section passes 

 are parallel, light passes freely through the analyzer to the eye. If 



FlG. 150. MlCRO-POLARISCOPE IN POSITION ON THE MICROSCOPE. 



Polarizer The Nicol prism under the stage of the microscope. 



Analyzer The Nicol prism over the ocular. 



Stage The stage of the microscope. 



Object The object on a slide. 



Objective The microscopic objective. 



S Set screw for clamping the analyzer to the tube of the microscope. 



Ocular The microscopic ocular in position. 



Pointer and Scale The graduated ring and pointer to show the amount 

 of rotation. 



A Handle for raising and lowering the analyzer to arrange it properly 

 with reference to the eye-point. 



these corresponding faces are at right angles, that is, if the Nicols 

 are crossed, then the light is entirely cut off and the two transparent 

 prisms become opaque to ordinary light. There are then, in the com- 



