PROFESSOR GRAHAM ON OSMOTIC FORCE. 
195 
times greater than that of the 1 per cent, solution in both series. The hydrostatic 
resistance of the membrane B falls olf in a remarkable manner in the later experiments, 
indicating an increased facility of permeation, which may influence the increased 
osmose in the last two observations of this series. The results otherwise of the two 
series exhibit a fair amount of correspondence, both in the degree of osmose and the 
amount of diffusate for the same proportions of alcohol in the two osmometers. It 
should be added, that in several instances the water in the jars was changed after 
the third hour of the experiment, with the higher proportions of 10 and 20 per cent. 
The alcohol was determined, after it had been concentrated by two distillations, by 
means of Drinkwater’s table of densities. 
Several experiments were made to determine the proportion of the diffusate of 
alcohol from 5 and 20 per cent, solutions respectively of that substance, in membrane 
osmometers. The mean proportion was as 1 to 3’02, which is mentioned here, as I 
was led at first to a different conclusion by earlier and imperfect experiments. 
Sugar.— The osmose of sugar in membrane was examined very fully, in the hope 
that the simple effect of diffusion would be exhibited without being modified by any 
chemical action, in a substance so entirely neutral. 
Crystallized cane-sugar was made use of. 
Table III. — Sugar in Osmometer D of double membrane for five hours. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
Sugar in 
solution. 
Rise in 
millimeter 
degrees. 
Same in 
grammes 
of water. 
Diffusate of 
sugar in 
grammes. 
Previous 
maceration. 
Hydrostatic 
resistance. 
Temperature, 
Fahr. 
per cent. 
1 
21 
1-027 
days. 
1 
min. 
4 
64 
1 
8 
0-395 
0-150 
9 
H 
63 
1 
19 
0-948 
0-140 
1 
H 
63 
2 
19 
0-948 
0-178 
1 
n 
66 
2 
19 
0-948 
0-182 
1 
n 
66 
5 
39 
1-900 
0-438 
1 
H 
67 
5 
49 
2-370 
0-480 
1 
H 
69 
10 
66 
3-239 
1-110 
2 
H 
72 
10 
79 
3-871 
0-853 
1 
H 
70 
10 
76 
3-713 
0-840 
1 
3 
67 
20 
121 
5-975 
1-376 
1 
3 
67 
so 
117 
5-688 
1-485 
1 
3 
67 
It was very desirable to find whether the deviations from a regular progression 
seen in the numbers for the osmose and diffusate in the preceding results are essen- 
tial, or accidental and peculiar to the present membrane. It was also desirable to 
find whether a membrane would stand the repetition of such a series of experiments 
and continue to give similar results. A double series of experiments were accord- 
ingly made with new membrane. 
2 c 2 
