CANE SUGAR. 149 



the data pertaining to Series I are omitted because the extent of the 

 dilution in that series is unknown. Throughout the three remaining 

 series of the first division the means of maintaining temperature were 

 very imperfect, and the dilution of the cell contents, as determined by 

 the loss in rotation, was large. These unsatisfactory conditions are 

 reflected in the large variations in the ratios obtained at different 

 temperatures for the individual concentrations of solution — that is, in 

 the ratios which are placed in the several vertical columns. 



Throughout the series of the second group, on the other hand, the 

 temperatures maintained were constant, or very nearly so, and there 

 was very little or no loss in concentration. The better conditions under 

 which V to VIII were carried out are likewise reflected in the closer 

 agreement of the ratios in the several vertical columns — the mean 

 variation for all concentrations being 0.007, and the largest for any 

 single concentration, 0.012. It is clear that any conclusions which 

 may be drawn from the relations found in the table should be based 

 upon the data in the second group only. An inspection of these will 

 show that: 



1. The mean ratios of osmotic to gas pressure for every concentration 

 of solution, as well as all the individual ratios, are considerably above 

 unity. This is also true throughout the first group. The observation 

 that between 0° and 25°, the osmotic pressure of cane-sugar solutions 

 is considerably higher than the calculated gas pressure of the solute has 

 been amply confirmed by later measurements. It is not necessary, at 

 the present time, to search for an explanation of this excessive osmotic 

 pressure, but the fact that all ratios have been found to become unity 

 at high temperatures suggests a concentration of the solutions through 

 hydration. 



2. The ratios, from concentration to concentration, are irregular, 

 but, in general, they diminish from the 0.1 weight-normal solution, 

 then show a tendency to become constant through the 0.2, 0.3, and 

 0.4 concentrations, and finally they rise again continuously through the 

 0.5 and all succeeding concentrations. The general trend is obviously 

 as stated, though it is somewhat confusing in its details. Later investi- 

 gations have shown that the ratio is relatively high in the 0.1 solution; 

 markedly lower, but constant, through the 0.2, 0.3, and 0.4; higher again 

 in the 0.5, and still higher in each succeeding concentration. This lack 

 of constancy of ratio from concentration to concentration suggests, but 

 does not prove, that the osmotic pressures of cane-sugar solutions do not 

 conform to the law of Boyle. 



3. The ratios at different temperatures are fairly constant for each 

 concentration. Constancy in this respect is a test of conformity to 

 the law of Gay-Lussac. It will be shown later that, between 0° and 

 25°, all solutions of cane sugar ranging in concentration from 0.1 to 

 1.0 weight-normal do obey this law. 



