442 Andersen — System Anorthite-Forsterite-Silica. 



and the boundary curve O P are left out in fig. 11, where con- 

 sequently the points B, C, O and P are not shown and the 

 point K is removed to the side of the diagram. This distorted 

 diagram, therefore, represents a true ternary system of the 

 same type as the anorthite-forsterite-silica system, but without 

 any breaking up of the components A and D and with only 



Fig. 11. 



~ - - - HX 



- - -, S 



one modification of the component H. In the two diagrams 

 the corresponding points are marked with the same letters. 



The eutectic field. — The mixtures within the part of the 

 diagram bounded by F M (field boundary Fo : CI en) and the 

 straight lines M A, A H and H F (fig. 9) behave ^ as if they 

 belonged to a ternary system anorthite-enstatite-silica. This 

 ternary system is of the simplest type, with no compounds, and 

 one ternary eutectic. The crystallization of mixtures of such 



