40 Rankin and Wright — Ternary System OaO-Al^0 3 Si0. 2 . 



footnote, page 16. Photographs of a solid model constructed 

 in this way are given in figs. 9-11. Fig. 9 is taken from the 

 Si0 2 end and shows the binary systems 0aO-SiO 2 and A1 2 8 - 

 Si0 2 and also the slopes of the ternary fields which have their 



Fig. 8. 



1625 



Si0 2 



Cnstobalit* 



AI 2 3 S.0 2 



Fig. 8. Projection of concentration-temperature diagram of ternary sys- 

 tem CaO-Al 2 3 -Si02 with isotherms and melting temperatures of compounds 

 and invariant points. 



origin in the two binary systems. In the same way fig. 10 

 shows the binary systems of CaO-Al 2 3 and Al 2 3 -SiO a and 

 their relation to the ternary system. Fig. 11 is a photograph 

 taken from directly above the solid model and shows the rela- 

 tive positions and slopes of the various fields. 



