228 



iV. L. Bowen — The Ternary System 



Table IV. 

 Temperature of Beginning of Melting. 

 Composition* 



. Pyroxene 



100(Di 83 En 17 

 100(Di, B En„ 

 100(Di 56 En 44 

 100(Di„En 63 

 100(Di 19 En 81 

 100(Di 9 . 5 En 905 



95(Di 75 En 25 

 95(Di i6 En 44 



95(Di 19 En 8l 



Si0 2 





 

 

 

 

 



5 

 5 

 5 



Fig. 14. 



Temperature 



1390 ± 4 

 1390 ± 

 1390 ± 

 1395 ± 

 1416 ± 

 1450 ± 



1365 ± 4 

 1375 ± 4 

 1400 ± 4 



Fig. 14. Showing three-phase-boundaries for the phases pyroxene, for- 

 sterite and liquid (true scale). 



Fig. 16 is analogous to fig. 13 and shows the relations at 

 various isotherms. 



The points a and b of fig. 16 for 1390° correspond with the 

 points L and K of the theoretical case fig. 12 (b). 



The Course of Crystallization in Typical Mixtures. 



We are now in a position to discuss, with the aid of the 

 three-phase-boundaries, the crystallization of typical mixtures. 



*The material was in each case subjected to preliminary treatment which 

 consisted in converting the mixture to glass and then crystallizing the glass 

 at about 1300 a . The reason for this treatment will appear later. 



