38 



merwin: media of high refraction 



must be standardized by means of a prism which is ground or 

 moulded. About equal parts of dried precipitated AsaSs and 



2.1 



2.0 



1.9 



X 



111 



o 

 z 



u 



> 



P 



o 

 < 



ir 

 u. 

 ui 

 a. 



1.8 



1.7 



1,6 



1.5 



20 



20 



PERCENTAGES 

 40 60 



80 



JOO 



80 



lOO 



40 60 



ROSIN 



Fig. 1. Composition and refractive index 



flowers of sulfur are intimately mixed by grinding moist with 

 alcohol. The mixture when dry is strongly heated in a test tube 

 which is not more than one-third full. A part of the sulfur will 



