SOLIDIFICATION OF ALLOYS AND MAGMAS 585 
the eutectic constituents, and an elimination of the composite 
texture. 
Furthermore, we do not make alloys in which the components 
are not perfectly miscible when molten, because in this case there will 
be separation by liquation and a defeat of the object sought by the 
mixture of the metals. But igneous-rock mixtures are not of man’s 
choosing. Consequently there will very likely often be encountered 
the case of mixtures of imperfect miscibility, with a first separation 
of the components of saturation, and their final solidification according 
to the laws of freezing. 
To clear up the intricacies of the problem, it is essential that 
extended research be conducted along the line of the few cases already 
worked out, beginning with the simpler conditions and extending 
the scope as circumstances warrant. With the electric furnace, 
desired minerals or rocks could be melted and could also be synthe- 
sized under any pressure; the pyrometer would give us the thermal 
reactions; finally with the microscope we could compare the structure 
of our artificial material with the natural rock in its original and 
remelted states. An investigation of this kind may reduce cases of 
seeming complexity to ones of comparative simplicity, by fixing a 
certain few of the components as of primary importance, and the rest 
of a secondary modifying nature. For example, while steel is a many- 
component alloy of Fe, C, Si, S$, P, and Mn, we treat it as a two- 
constituent mixture of Fe and C as of greatest importance; the other 
elements have their influence mainly in their effect on the transition 
ranges of the carbon and iron. 
At any rate, the thermal investigation has the great advantage of 
getting at the internal reactions, and can be backed up by our present 
methods with the microscope, and otherwise, which are suitable only 
for the end reactions. ; 
In conclusion, it is well to bear in mind that the laws of equilib- 
rium of solutions show that the melting-points of the constituents are 
of no service in predicting the order of their separation in the solidi- 
fication of the magma. And is it going too far to predict that the study 
of the freezing-point diagrams of the conditions of this separation may 
result, as did Van’t Hoff’s application to the carnallite deposits at 
Strassburg, in economies in the recovery of the metals from their ores ? 
