( t93 ) 



besides the conuodal lines enrliug on the side l^l^ iV^ also counodal lines 

 ending on the side A' A. Both plaits extend more and more when 

 the temperature falls and the two connodal lines approach each other 

 continually ; the crosses on the dotted line d e indicate the plait- 

 points of the different connodal lines. We are therefore led to 

 suppose that in the end the two plaits merge into each other ; yet 

 it was imposible to demonstrate this experimentally, because, in 

 consequence of the appearance of the solid phase succinonitrile, the 

 left connodal line below iir 5°5 and the right one below ^ 4°5 

 indicate only less stable equilibriums. 



Quite different are the phenomena in the system water, anilin and 

 phenol in fig. 2. Here there appears namely but one plait on the 

 ^-surface. Above 1G7° a separation of a liquid in two layers can 

 never occur in this system; the ^-suiface is in every point convex- 

 convex downwards. At 167° there appears a plait-point on the side 

 W An ^, its projection being e. As the temperature falls the 

 plait extends and we get connodal lines as in fig. 2, in which 

 the crosses again indicate the plaitpoints. The plait continues to 

 extend and reaches at 68° the plane TF Pk ^ in a point, the projection 

 of which is indicated by d] the connodal line has a form like the 

 one which in fig. 2 touches the side Ph W in point d. At still lower 

 temperatures the plaitpoint on the ^-surface disappears; the plait 

 extends from one side to the other, so that two entirely separate 

 convex-convex parts are formed. The connodal line now has fallen 

 into two parts, separated from each other, both ending on the sides 

 Ph W and An W. At further lowering of the temperature the con- 

 nodal line keeps its form; the two parts move however continually 

 farther from each other and at last some of the points represent 

 less stable states, as solid phases, viz phenol and a combination of 

 phenol and aniline are formed. 



The preceding investigations have led to a theoretical and expe- 

 rimental investigation of different curves ; in these pages a survey is 

 given of some of the experimental investigations. 



Let us take the connodal lines of fig. 2 ; below 68° no plaitpoint 

 appears on them ; at 68° it appears in point d and the temperature 

 rising it moves along the line de from d to e where it disappears 

 at 167°. It is however very difficult to realize these plaitpointcurves 

 experimentally; neither has this been done in the different systems 

 investigated by Mr. Schkeinemakees. He has however determined 

 ^another curve, which will not much deviate from it in the two 

 systems mentioned above. It is the line of the critical mixingtem- 

 peratures which coincides with the former in at least 2 points, 



