254 Wisconsin Academy of Sciences , Arts and Letters. 
cm. The temperature then rose gradually to 18° C. during the 
succeeding three days, when the pressure was 46.3 cm. 
55) In this experiment the inner liquid was a solution of 
cane sugar in pyridine containing 0.25 gram-molecule per liter 
of solution, while the outer liquid was a solution of cane sugar 
in pyridine containng 0J25 gram-molecule per liter of solu¬ 
tion. The pressure rose slowly, the mercury column reaching a 
height of 137.5 cm. at 16.8° C. By far the most of this was 
accomplished during the first two days. The final measure¬ 
ment just given was taken after thirty days. The experiment 
was then left undisturbed for twenty-six days longer. The 
pressure began to diminish gradually and finally measured only 
89 cm., when the experiment was discontinued. The membrane 
when examined at the end of this time was to all appearances 
intact and but slightly changed, if at all. 
56) Two experiments were made with solutions of cane 
sugar containing 0.25 gram-molecule of cane sugar per liter of 
solution in pyridine as the inner liquid, and pure pyridine as 
the outer liquid, employing in this case, however,, a common 
thick sheet rubber 1 —such as is used on the ordinary foot-power 
laboratory bellows— in place of the finer vulcanized caoutchouc 
used in the other experiments. The experiments were con¬ 
ducted side by side as duplicates of each other. The pressure 
rose gradually, the mercury column reaching a height of 43.0 
cm. in one case and 39,5 cm. in the other at 22° C. The rubber 
was found to be much softened when examined at the end of 
ten days, the duration of the experiments. The maximum pres¬ 
sure was practically reached after fort}’-eight hours. The 
pressure diminished gradually after seven days. Small amounts 
of sugar were found in the outer liquid, though the exact 
amount was not determined. 
From the results just detailed it is evident that the methods 
employed are not capable of yielding concordant values. 
Though only attempts to measure osmotic pressures of sugar 
solutions in pyridine have been described, similar experiments 
were made using lithium chloride and silver nitrate solutions 
in pyridine. In these cases the results were no more; concordant 
than in those in which sugar was solute. At first it was thought 
