CaO 



49 



29 



34-3 



35 



37 



A1 9 3 



30 



52 



52-7 



55 



54 



SiO„ 



21 



19 



13- 



10 



9 



32 Rankin and Wright — Ternary System OaO-Al 2 3 -/Si0 2 



Table VIII. 



Melting temperature of various compositions within field 11-12-G-H 

 primary phase is 3Ca0.5Al 2 3 . (M. P. 1720° ±10°). 



Composition 

 Weight per cent 



Temperature of melting 1540 1590 1570 1590 1509 



X. The field of CaO. Al 2 3 . (F-G-12-13-U).—Tsib\e IX 

 gives the melting temperatures of various compositions within 

 this field. 



Table IX. 



Melting temperature of various compositions within field ^-(2-12-13-14 ; 

 primary phase is OaO.Al 2 3 (M. P. 1600° ±5°). 



Composition 

 Wt. per cent 



CaO 



A1 2 3 



Si0 2 



45 



47 

 8 



48*5 

 45- 

 6*5 



36*7 



58-1 



5-2 



45 



50 



5 



40 



55 



5 



47 



49 



4 



47*5 



49*5 



3-0 



Temperature 

 of melting 





1456 



1361 



1549 



1468 



1535 



1432 



1421 



XI. The field of 5Ca0.3Al 2 0, (E-F-U-15).—$C&O.ZK\0 % 

 occurs in two forms, a stable form and an unstable form which 

 occurs in melts with considerable frequency. The melting 

 slope of the narrow field for the stable form follows from the 

 melting temperatures of the boundaries which have been ascer- 

 tained. 



XII. The field of 3CaO.Al 2 0, (E-15-16-17-D)— 3CaO. 

 A1 2 3 is a compound unstable at its melting point, wherefore 

 its composition lies outside of its field of stability. Table X 

 gives the melting temperatures of various compositions within 

 this field. 



Table X. 



Melting temperature of various compositions within field #-15-16-17-1); 

 primary phase is 3CaO.Al 2 3 . 



" CaO 



Composition ^j q 

 Wt. per cent q-A 3 



IS? 16 1448 1435 137 ° 149 ° 1437 139 ° 



58-5 



57'5 



52-5 



60 



55 



52-5 



33-5 



35* 



41* 



35 



40 



42-5 



8* 



7'5 



65 



5 



5 



5- 



