( 818 ) 
the point lying on the left z,, then 
d 
v,,dp = (#, — 4,) (=) pits + nd 
© Jp 
“dp «  (òp\ dz, & 
AT Lee Oss oT ie 
holds for the equilibrium between these two liquids for the point 
lying on the right. 
2 
or 
In the second member the second term (5) holds for the section 
Tas 
for constant value of x, the shape of which section we will determine 
— in the first term of the second member we have omitted the 
index 7’ to avoid great complication in our notation. The shape of 
the line of equilibrium between the two liquids is known of a 
pse-section of the surface of saturation, if three-phase-pressure occurs. 
It is a curve which ascends steeply in the points 2 and 3, and. 
e 
OE 
reaches a maximum value between them. In the point 3 | =} hasa 
Oase 
. ° . ‚de, . Ore . . 
high negative value, and if — is positive, which is the case on the 
dT 
is smaller 
d 
lower side of the righthand half of the dotted curve, S 
ry 
123 
le, 
C 
dT 
Op 2 
than eS . On the lefthand part of the lower side is negative, 
Tog 
07 
. UFR Ea 
but there A Fe positive, so that we arrive at the same result 
U) 93 
there. On the upper side we come to the opposite conclusion. So if 
we draw the upper branch of the section of the surface of saturation, 
such a modification must be applied between the limits of the tempe- 
rature, which are to be derived from the dotted curve of fig. 39, 
that the three-phase-pressure lies below this curve — which was, indeed, 
a priori to be expected. And by a comparison of the two equations: 
dp __ (0p\ de, Op 
Ch aR iN aa eh + om : 
dp (Op de, En Op 
Cie oe) dT OT yam 
from which follows: 
Op Op 
Ow 13 a 
Op Op _ da, 
Ga x oT “13 a dT 
and 
