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the phases which shows this phenomenon in the system iron-carbon, 
is graphite. Graphite is the second component, and when there was 
no deviation from the ordinary state of things the succession of the 
solid phases, which coexist with the saturated solid and liquid solu- 
tions, would be such that the carbon content continually increased 
in one direction. Starting at the ordinary temperature we find, how- 
ever, this that first graphite, and then carbides are formed, which 
latter however will finally have to give way before the graphite 
again. 
Now it would follow from the preliminary investigations of Wirtorr, 
when namely the equilibria examined by him are stable, that twice 
such an inverse deposition takes place in the system 7ron-carbon, 
for with rise of temperature he found this succession: 
C—-Fe,C—FeC—Fe, C—Fe,C ? 
from which it appears that a solid phase with a hiyher percentage 
of iron sueceeds not only C, but also Fe C. 
This phenomenon of inverse occurrence of solid phases is still so 
strange to us that it is expedient theoretically to enter a little more 
deeply into this matter. 
To throw the peculiar element into strong relief, I shall discuss 
the phenomenon led by the same example as I used as an illustra- 
tion in the Zeitschr. f. Elektrochemie. So I shall suppose for a 
moment that the succession of the solid phases which coexist with 
saturated liquid solutions with rise of temperature, is this: 
C — FeC — Fe, — C. 
If we now suppose that the situation of the lines for the three- 
phase equilibrium with one of these solid phase, so for S + L + G, 
is as has been represented in fig. 1, the easiest way to find the 
situation of the other three-phase lines is to prolong the two three- 
Ji 
Fig. 1. 
phase lines be and de metastable through the point of intersection 
c, till we meet the metastable middle portion of the three-phase 
line for C+ L+G in g resp. f. 
