378 
contains comparatively much carbon, whereas compounds with a 
smaller percentage of carbon will probably behave like iron. 
If we now assume that Vs, and Vg, are both positive, then it 
is possible that the denominator of equation (II) is negative, and the 
dp\ . ee. 
= will begin in 
dl’) 5,5,L 
this case in 6 with a positive value. In the second quadruple point 
g the numerator is positive, as I showed before, and consequently 
dp : ; 
T | — |} will be negative. 
aT S SD 
Reasoning in the same strain as before in the discussion of the 
three-phase line for 5,-+5,-+ G it follows that the three-phase line 
for S, +5, + L will possess a pressure maximum, as has been 
schematically represented in fig. 4. 
numerator also having a negative value at b, r( 
Fig. 4. 
When on the other hand Vg, is positive and Vs, negative, the 
: dp 
denominator has a positive value, and 7 (5) will consequently be 
SSL 
negative at 5 and positive at g, in consequence of which the P,7- 
figure becomes as it has been drawn in fig. 5. 
A metastable minimum cannot occur here, because the three-phase 
lines for C+ FeC+G and for C-+ FeC-+L pass continuously 
