( 556 ) 
Chemistry. — “Critical terminating points m three-phase lines with 
solid phases in binary systems which present two liquid layers.” 
By Prof. H. W. Baknuis RoozeBoom and Mr. B. H. Bücnner. 
(Communicated in the meeting of January 28, 1905). 
Up to the present only one critical terminating point has been 
found in systems of one component, namely in the equilibrium 
liquid-vapour. If this is represented by a p,¢-line this suddenly 
terminates in the point where liquid and vapour have become 
identical. There exist at the moment no well-founded reasons to 
assume critical terminating points also in the equilibria solid-liquid 
and solid-vapour. We will not further consider these here. 
In systems of two components we get instead of a critical point 
liquid-vapour, acritical 
line A,A, which con- 
nects the critical points 
of the components. In 
a p, t, #-diagram this 
line runs in space, 
P 
here its p, projection 
is only indicated. (AK, 
and BK, are then the 
equilibria-lines liquid- 
vapour for the com- 
ponents A and 2). If 
there is a homogeneous mixing for all concentrations in the liquid 
phase, this will then be the only critical line. 
The recent researches of Smits!) 
have shown how in some binary 
P nap * mixtures the equilibrium line 
x, for solid B with liquid and 
A B vapour may meet this critical 
line (it is necessary that the 
t melting point of B should be 
Fig. 2. situated higher than A). There 
are then two such meeting-points p and q with the two parts op 
and qg& of the three-phase line. This line therefore acquires two 
critical terminating points owing to its meeting the critical line liquid- 
vapour. Between p and q both lines cease to exist. 
1) These Proceedings 1904, 
