THE MINERALOGRAPHY OF THE FELDSPARS 247 
POTASH SODA- LIME FELDSPARS 
-F 
oe 
LIQUIDUS 
E 
120 1530 
Na-F ISOTHERMS Ca: 
Fic. 11.—The liquidus and solidus surfaces of the ternary system, potash-soda- 
lime feldspars, projected to the base and represented by contours of equal tempera- 
tures or isotherms. 
