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bring a sufficient quantity of / into a space. We cull this an in: 
congruent sublimation of £ + 1”. 
C. The point / is situated between /” and r. This case is exactly 
analogous with the previous. 
D. As transitioncase between A and 5 (or C) point 7 coincides 
with /” (or £). We shall refer to this later. 
When we lower the pressure below P,, the points of inter- 
section disappear. In the case, mentioned sub A, then the two curves 
are situated outside one another; the equilibria /’) + G and #” + G 
then both occur in stable condition. On further decrease of P these 
curves disappear; that of # under the sublimationpressure of /, 
that of F’ at the sublimationpressure of 2”. 
In the case B the two curves touch one another internally in 7; 
further the curve of /” is surrounded by that of /. On decrease of 
P both the curves contract and then two cases are imaginable. 
When in the vicinity of r curve F contracts more rapidly than curve #7, 
two points of intersection arise; when, however, curve /” contracts 
more rapidly than curve F, curve /” happens to fall completely 
within curve #. In order to show that only this latter is the case, 
we apply (5) to the point of contact r of the two curves. When 
we represent / by /, formula (5) is true for curve F. When we 
represent /’r by /, then for curve #” a formula (5) is true, in 
which /, @ and 2 are replaced by /’, @ and 6’. As the value of AV, 
is very approximately the same in both the formulae, the relation 
di: dl’ =U :1. follows. This means: on change of P the velocities 
of the two curves in the vicinity of their point of contact are in 
inverse ratio to one another, as the distances from 7 to F and Ff”. 
In the case, now under consideration, (/ > //) curve /” consequently 
moves in the vicinity of the point 7 more rapidly than curve /. 
On increase of P consequently two points of intersection arise; on 
decrease of P these points of intersection disappear and curve /” 
is completely surrounded by curve /. The equilibrium # + G occurs, 
therefore, in stable” condition; the equilibrium /” + G can occur 
only in metastable condition. 
When we lower the pressure still further, firstly curve 4” disappears 
and afterwards curve /’; consequently the sublimation-point of the 
substance /” is metastable. In the case A, / and /’ may both 
sublimate without decomposition ; in the case B only / sublimates 
without decomposition, while /” converts itself into /’+ G. | 
As to the case B analogous considerations apply to the case C. 
From the previous considerations among others the following can 
be deduced: To each temperature 7’ belongs a definite congruent or 
