15000 

 (1460°) 



14000 



13000 



12000 



11000 

 (1145°) 



of the Composition MgSiO v 

 12 



419 



! 



































1 





































































1 









As 



/ 























! 







/ 

































i/ 





/ 



























i 





/ 





1 



























I 





/ 



Z? 





































1 

































/ 





1 



































/ 







































































/ 







































/ 



































1 1 



i 



































i 





















































































































































































1 









































































r^ 





































_ 













































































































f 





































f 





































L 





































r . 





































r 





































r 





































i_ 





































1 

























































































































































































































































Fig. 12. 



Time — 1 division = 1 minute. 



I = Albite glass. 

 II = Albite. 



