665 



temperature in the point X; the increments L.viL;/,... have, 

 therefore, to satisfy (9) [XVII] and (10) [XVII]. This is, however, 

 also true for tlie increments A.t/Ay,. .. in the point A^ of curve 

 FiiT=7'x), as this curve has a maximum- or minimum pressure 

 in the point A^. 



In the same weiy the follov^^ing appears yet also. When the curve 

 Fi (R) has a turning-point S, in the P, 7'-diagram, then in the 

 concentration-diagram the three curves Fi{R),Fi {P^=P^) and 

 Fi{T=zTJ touch one another in the point S. 



Corresponding points on the ?i — 1 other curves belong (o each 

 point X (or *S) of a curve Fi(R); consequently the properties 

 deduced above are valid also for each of those curves. 



We shall apply now those general considerations to the ternary 

 equilibrium E=B-\-L-{-G, which we have discussed in commu- 

 nication XVI in connection with the tigs. 6 and 7. As this equilibrium 

 is a ternary one, it may be represented in a plane viz, in triangle 

 ABC of fig. 6. As i^ is a phase of invariable composition, each of 

 the equilibria is represented by two curves, viz. : 



FiR) by the curve L{R) and G {R), 

 F{P=P,) „ „ „ L(P=. P,) and G{P=P,), 



F{T=T^) „ „ „ L(T=1\) 2.m\ G{T=1\). 



Curve L (R) is indicated in tig. 6 by curve mSM (in fig. 7 this 

 curve mSM has a turning-point in S); curve G {R) is not drawn 

 in fig. 6. Further in fig. 6 we tind several curves L {T = 1\) ; 

 rt 6 c r/ represents viz. a curve L {T =z: T^j) (we have to bear in mind 

 that Ta=z Tb =: T^=z TJ); efgh represents a curve L {T =: Te), 

 iSk a curve L{T=:Ti) and In a curve L{T=zTi). The liltle 

 arrows indicate the direction in which the pressure increases along 

 these curves; this is a maximum on branch MS, a minimum on 

 branch mS of the turning-line. The reader may imagine the cur\es 

 L(P=P,), G{T=T^) and G{P—P,) which have not been drawn 

 to be also indicated in fig. 6. 



Let us now imagine in tig. 6 (o be drawn through a point x 

 of curve mSM the curves L[T^= Tx) and L{P=: Pj);' in accord- 

 ance with our general considerations, those curves must, therefore, 

 come in contact with one anothei' in the point x. When we take 

 the point b on m S M, then curve L {T =z 2\), which is represented by 

 abed and the curve L {P= Pt), which is not drawn, touch one 

 another in b, therefore. In the point c curve L {T =z7\) = a b c d 



