( 693 ) 
more, the coexistence surface contains no longer a point with 
fier: values for 2, and 4}, and a mixture of aie composition has 
become a permanent gas. 
After these preliminary considerations we may begin the discussion 
of equation (1). 
A. We find, if we keep x, and 4, constant: 
d; W, 
T can eee 
dr Ti Yi Va1 
The quantity p in this equation represents the limiting value of the 
pressure, for which a mixture with the given composition 2 and y, 
is still homogeneous. If the phasis is a gas phasis, an increase of 
the pressure, 7 being kept constant, would cause condensation. If 
it is a liquid phase, decrease of the pressure would make part of 
it evaporate. This equation, which for the components themselves 
is nothing but the equation of CLAPEYRON, has for a ternary system 
the same form as for a binary one, and would also have the same 
form for a system of still more components. I suppose the shape 
of such a p,/’ curve to be known from the knowledge of the pro- 
perties of a binary system; here I only point out that the peculiar 
points of this curve are found, if Ws, or v2, or both these quantities 
d, 
are zero. If vg, = 0, then (=) = Oy te We) =10; then Sp ais. a 
maximum. If both values are zero, as is the case in the plaitpoint, 
d. ‘ ‘ EE 
we get the value of = in an indefinite form, yet from the position 
d, ' 
of the plaitpoint we may conclude the real value of (4) „ARS 
dT? pj 
lies on the vapour sheet, vz, and Ws, are both negative, therefore 
the value will be positive, and the greater as it gets nearer to the 
contour. If it lies on the liquid sheet, between the border and the locus 
dpi ; ; 
for which Ws} = 0, then (=) is negative. If we want to bring 
Pl 
i) in an analytical form, we have to write: 
Pl 
OPEN ae de (Ean) 
1 Ge)? dd en Ri 
For 
d d 
(€91)» = (&2—#1) — (02) = — (eye) an tienes 
4 
