REPRESENTATION BY ZETA FUNCTION 325 



Suppose this line cuts the WW axis in the point Po(fo,0). 

 Then 



^2 "To f 2 ~ f 1 



X2 X2 ~ Xi 



Allow the points Pi and P2 to coalesce in the tangent point 

 Qmi^m, Xm), the tangcut line passing through Pq. Then we get 



or 



U/. 



fo — r»n ~" ^"i I J ) — (M2)x = z^. 



This result shows that the pure solid phase corresponding to the 

 point Po on WW is in equilibrium with the liquid x^ determined 

 by the tangent from Po to the f -curve. It is to be observed 

 that Po is {W) in the notation of Schreinemakers. 



