M 



then A K is negative betweeji this point H and the terniinatingpoint 

 of the curve on side JJC. It is apparent tVon» the |)osilion of the 

 cnrves sc and sii (tig. 6) that point s is chosen on that part of the 

 qnadrnplecnrve, where £\V is positi\e. We distingnish now again 

 the same tiiree cases as above. 



1*'^ The vaponr is represented by .s\. 



It is apparent from the position of the points F, B, s and Sy witli 

 respect to one another that the fourphase-reaction : 

 F+ L,:^JJ + Gs.dxVyo) 



F-\- L^ G (Curve sc) 

 F-\-B-\- L 



B-{- L-\- G (Curve sa) 



F-^B^G 



takes place; it proceeds from left to right with increase of volume 

 Hence it follows that the equilibria written at the right of the 

 vertical line occur under lower pressures, the equilibria at the left 

 occur under higher pressures. In accordance with the above we find, 

 therefore, that starting from s (fig. 6) the pi'essure increases along 

 sc (equilibrium F -{- L -\- G) and decreases along sa (equilibrium 

 5 + Z + G). 



2'^^ and 3"^ Also in these cases we find agreement with the 

 previous considerations. 



When a point of maximumtemperature if occurs on the quadruple- 

 curve B -\- F -{- L -\- G, then two points of intersection s occur at 

 temperatures a little below Tjj. When we consider now a point 

 of intersection s between H and the terminatingpoint of the qua- 

 druplecurve on side BC, then A I'' is negative. This involves that 

 above in 1**^ — 3'^' increase of P is replaced l\y decrease of F and 

 reversallj. We find also the same when we consider the threephase- 

 triangles solid-liquid-vapoiir. To be continued.) 



Chemistry. — " On ike quaternari/ s//stem -. KCl—Qu Cl^ — Ba Cl^—H., 0." 

 By Prof. ScHREiNEM AKERS and Miss W. C. de Baat. 



(Communicated in the meeting of October 31, f914). 



In a previous communication ') we have already discussed the 

 equilibria occurring in this system at 40° and at 60° ; the results of 

 the analysis on which these considerations are based, we have hitherto 

 not yet communicated. Now we will communicate the re^iulls of the 

 analysis ; all the points, curves etc. quoted in this communication 

 apply to the two figures of the previous communication (1. c). We 

 want to draw the attention to the fact that fig. 1 represents the 

 equilibria at 40° and fig. 2 the equilibria at 60°. 



1) These Communications (1912; 326. 



