36o 



HAROLD L. ALLING 



feldspars outside of the anorthoclase-cryptoperthite ranges exhibit 

 the same phenomenon, although to a lesser degree. As has been 



KAISi^Os 



.V Triclinic" Series 



NaAIQi n ^^^ •^J'.'^ <S> <S> ^ S> S" '^ <^ 



naAibisUs " 'I' 1 1 <i <i/ <i/ ^- .^r <i> ii> 



CaAlsSiaOs 



KAISiaOs 



Monoclinic" Series 



NaAISiaOs 



^ 1 '^ v 



<?•%■ 1, <t,> I.- 



CaAlzSigOg 



Fig. 4. — Plot of specific gravities of the potash-soda-lime feldspars shown by iso- 

 gravity lines. Upper figure: Microcline, albite, anorthite, "triclinic" series. Lower 

 figure: Orthoclase, "barbierite" and " barbierite "-rich anorthite, "monoclinic" series. 

 Offered with fuU knowledge that they leave much to be desired. 



already stated, the degree to which they under cool is dependent 

 upon their origin; consequently it follows that the position of the 

 solubility lines (perhaps best appreciated when projected to the 



