Chemistry. — ''On Milksugar". II. By Prof. A. Smits and J. Gnj.is. 

 (Communicated by Prof. S. Hoogewerff.) 



(Communicated in the meeting of Sept. 29, 1917). 



The Ternary Pseudo T, x-jigiire. 



Wiien we draw up the pseudo- ternary 7\ ^--figure, we come to 

 the following representation. (Fig. 9). 



In the side plane for «-anhydride— H,0 

 we know the initial solubility from 0° 

 to 25", (determined by Hudson loc. cit.) ; 

 further the situation of the eutectic point 

 at —0.3° and 0.27 mol. % « (point d). 



We found the melting point of « at 

 222°,8 and that of ««^ at 201 °,6. With 

 regard to the real transformation point 

 of a„q, i. e. the point where under the 

 pressure of 1 atm. the following con- 

 version takes place : 



f^aq -» « -j- Z. 

 we have been able to ascertain that it 

 lies above 100°; for when «-anhydride 

 was brought ^t 100° in a saturate milk- 

 sugar solution, a marked generation of 

 heat still took place as a proof that at 

 this temperature hydration of the solid 

 '« «-anhydride still occurs. 



If instead of a saturate milksugar 

 solution Dure water of 100° is taken, 

 this generation of heat is not observed, because the velocity of 

 solution is very great at this temperature, and the negative heat 

 of solution then hides the smaller positive heat of hydration from us. 

 In the side plane of the system /i-anhydride-water we know the 

 initial solubility at 0°, the eutectic point d' lying at — 2°,3 and 2,2 

 mol. 7o /?, and further the melting point of H^O (point a), and the 

 melting point of /i-anhydride b\ lying at 252°,2. 



42 

 Proceedings Royal Acad. Amsterdam. XX. 



Fig. 9. 



