identifying; polarized light 



235 



A NEW METHOD OF IDENTIFYING POLARIZED LIGHT 

 REFLECTED FROM SMALL OPAQUE CRYSTALS. 



LeROY d. weld. 



The method is a modification of one used originally by Voigt 

 for the identification of elliptically polarized light. The light 

 under examination passes first through an arrangement of quartz 

 wedges acting as a Babinet compensator, then through a "rota- 

 tor'' consisting of another pair of quartz wedges cut perpen- 



Fig. 41A. View of Apparatus. 

 Fig 41B. Typical Spot-Patterns with Selenium (19 and 20), and ComparisMn 



Pattern (21). 



dicular to the axis, one from right-handed, the other from left- 

 handed quartz: and finally through a large Nicol prism. The 

 result is that the field is filled with rows of black spots in regu- 



