Alkemade theorem

In this case, the Alkemade line C-AB does not cross die boundary curve ef) between these primary phases. Now, we state the Alkemade theorem in a more general form ... 

Figure 3.6 Compatibility triangles (dashed lines) superimposed on the stability fields 1 to 10, and directions of falling temperatures on the phase boundary curves (arrowheads), determined according to the Alkemade theorem.

Alkemade theorem The direction of falling temperature on the boundary curve of two intersecting primary phase areas is always away from the Alkemade line. If the... 

The arrows indicate the directions of falling temperatures as determined by the Alkemade theorem (see footnote 5). For clarity, not all possible arrows are shown. 

Figure 3.26 Cotectic (compatibility) triangles (solid lines) in the ternary diagram Ca0-Al203-Si02 (mass%). In the Si02-rich portion, three important triple points are indicated at the intersection of the phase boundaries (dashed lines). The arrows show the direction of falling temperatures according to the Alkemade theorem...

---