The Ternary System MgO-Al t O t -SiO v 305 



Table 2. 



Quenchings which determine the limits of the field of forstcrite 

 (2MgO.SiO,) ; see also Table 9. 



Phases present, glass -4- %HgO.SiO... 

 Composition Weight Per cent Temp. Time 



MgO A1A Sid 2 in hours 



310 220 47-0 1450 -5 



300 20-0 500 1450 -5 



26-0 220 520 1370 -5 



28-0 20-0 520 1400 -5 



260 200 540 1377 -5 



320 110 570 1465 -5 



Table 3. 



Quenchings which determine the limits of the field of clinoenstatite 

 (MgO.SiO,) ; see also Table 10. 

 Phases present, glass -4- MgO.SiO*. 

 Composition Weight Per cent Temp. Time 



MgO A1A SiO, in hours 



25-0 180 570 1360 -5 

 30-0 100 600 1465 10 



Table 4. 



Quenchings which determine the limits of the field of Si0 2 ; 

 see also Table 11. , 



Phases present, Si0 2 -4- glass. 



Composition 

 MgO 



Weight 

 ALA 



Per cent 

 SiO, 



Temp. 



Time 

 in hours 



200 



170 



630 



1370 



•5 



150 



20-0 



650 



1390 



•5 



27-0 



8-0 



650 



1475 



■5 



100 



230 



67-0 



1445 



•5 



90 



220 



690 



Table 5. 



1450 



•5 



Quenchings which determine the limits of the field of 

 (ALO : ,.SiO,) ; see also Table 12. 



silliman 





Phases present, glass -4- 



AW,,.SiO„. 





Composition 

 MgO 



Weight 

 AL.0 3 



Per cent 

 SiO. 



Temp. 



Time 

 in hours 



120 



460 



420 



1575 



•5 



160 



38-0 



460 



1490 



■5 



160 



350 



490 



1465 



2-0 



150 



350 



50-0 



1500 



•5 



150 



34-0 



51-0 



1465 



10 



12-4 



31-6 



560 



1490 



•5 



10-4 



26-6 



630 



1425 



■5 



90 



24-0 



670 



1450 



•5 



7-0 



22-0 



710 • 



1475 



•5 



