Ferguson and Merwin — The Ternary System. Ill 



The Melting Temperatures Within the Fields. 



The temperatures at which charges with compositions 

 lying within the fields become completely fused are given 

 in Tables XIV-XXI, inclusive. 



Table XIV. 



Melting temperatures in the silica field: Melting point of eristobalite 



1710 ± 10°C. 



Time 

 Composition wt. % Temp. in Phases present 



CaO MgO Si0 2 °C. min. 



23 7 70 1675 120 Glass 



previous charge reheated 1638 30 Glass -f- crystals 



23 14-5 62-5 1375 20 Glass -f- trace crystals 



25 10 65 1485 45 Glass 



1472 15 Glass 4- trace crystals 



26 7 67 1546 10 Glass 



1536 10 Glass -f- crystals 



30 5 65 1463 15 Glass -f crystals 



1472 10 Glass 



31 7 62 1347 20 Glass 



1343 20 Glass -j- trace crystals 



Table XV. 

 Melting temperatures in the diopside field; melting point of diopside 1391°C. 



Time 

 Composition wt. % Temp. in Phases present 



CaO MgO Si0 2 °C. min. 



28 13 59 1375 10 Glass 



1370 10 Glass -f crystals 



30 15 55 . 1375 15 Glass + crystals 



1381 10 Glass 



The melting temperatures of compositions lying within 

 the fields of the /?CaO.Si0 2 or wollastonite solid solu- 

 tions and the 5Ca0.2Mg0.6Si0 2 solid solutions must be 

 obtained from the temperatures of the boundaries, as the 

 fields are too narrow to warrant an investigation. 



Table XVI. 



Melting temperatures in the aCaO.SiO, field; melting point of aCaO.SiOo 



154.0 °C. 



Time 

 Composition wt. % Temp. in Phases present 



CaO MgO Si0 2 °C. min. 



32 6 62 1370 15 Glass + trace crystals 

 35 5 60 1402 10 Glass 



1395 10 Glass + crystals 



40 5 55 1468 10 Glass -f trace crystals 



