( 456 ) 



as this will be possible, as to the inner condition of the cold lime- 

 containing sugar solution ; on the other side, the insight gained in the 

 phenomena at 80° will, perhaps, facilitate our investigation as to 

 the conditions at a lower temperature. 



F'rom the experiments mentioned (table 2) it appears that the 

 definite condition of equilibrium of the complex investigated consisted 

 in the coexistence of calcium hvdroxide and solution. 



In the above cited treatise, Claasskn comes to the conclusion that 

 on warming solutions treated with lime at the ordinary temperature 

 ("saturated") "stets audi nach vielstilndigein Riihren, erheblich mehr 

 Kalk gelost (bleibt), als sich bei der höheren Temperatur unmiltelbar 

 lösen würde". This conclusion does not seem to us justified. Ci.aassen's 

 determinations occupied only 57-^ hours; moreover, from his figures 

 it is evident that the alkalinity at that moment ^^namely, after öVj 

 hours) was still decreasing. To us, however, it appears very probable 

 that on shaking for a sufficiently long time (in our case more than 

 30 hours) the condition of equilibrium would have set in. As, how- 

 ever, both the yellow colour of the solution and the results of the 

 analysis indicated that the sugar commenced to decompose perceptibly 

 it was obvious to start for the determination of the condition of 

 equilibrium, from a complex, the composition of whose phases was 

 removed less from the condition of equilibrium. 



In a small bottle were placed 5 grams of calcium hydroxide and 

 10 grams of water, the whole was heated to 100°, boiled for a 

 moment and then suspended in the thermostat at 80° (± 0.2°). In 

 this was also introduced a small bottle containing so much of a 

 sugar solution of a definite concentration that, after mixing with the 

 10 grams of water in the other bottle a desired sugar concentration 

 (of 5, lO^/o etc. respectively) was approximately obtained. After it 

 could be taken for granted that everything had attained the same 

 temperature, the contents . of the bottles were mixed (cooling being 

 carefully avoided) and shaken for the time desired. The results of 

 the analysis of the liquid phases are communicated in table 5. 



The figures for a 10" \ solution agree well with those found by 

 Cla ASSEM at the same temperature. The time of his experiments was 

 60 minutes; evidently the equilibrium was thereby attained somewhat 

 more rapidl}', which can be attributed to the calcium hydroxide and 

 the whole modus operandi. Yet it appeared to us still a little doubtful 

 whether in Claassen's experiments the equilibi'ium had been fully 

 attained, because after one hour the lime content of the 10andl37o 

 solutions was still falling while after that time that of the 16.7 and 

 33.37o solutions was still rising. 



