15 



of each fraction. The specific gravity of the first 92 per cent dis- 

 tilled is seen to be very uniform, as it varied only from 0.8660 to 



100 



90 



80 



70 



I 



"3 60 



#50 



it! 



30 



20 



7 



INDEX Of ftFFftACT/O/V - /S* C. 



FIG. 7. Percentage weight-index of refraction curve for a gum turpentine. 



[Cir. 152] 



