206 
PROFESSOR GRAHAM ON OSMOTIC FORCE. 
Table XIII. — Carbonate of Potash in Osmometer B of single membrane 
for five hours. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
Proportion 
of salt. 
Rise in 
millimeter 
degrees. 
Same in 
grammes of 
water. 
Diffusate 
in grammes. 
Previous 
maceration. 
Hydrostatic 
resistance. 
Temperature, 
Fahr. 
per cent. 
2 
635 
28-576 
0-514 
day. 
1 
min. 
20 
66 
2 
695 
31-236 
0-548 
1 
20 
68 
10 
892 
40-128 
2-897 
1 
16 
68 
10 
900 
40-508 
3-045 
1 
16 
68 
The fluid was removed from the water-jar at the expiration of the third hour, and 
replaced by distilled water to prevent the reaction of that portion of the salt which 
had already reached the jar upon the progress of diffusion from the osmometer, both 
in the preceding and the following series of experiments. 
Table XIV. — Carbonate of Potash in Osmometer D of double membrane 
for five hours. 
Proportion 
of salt. 
Rise in 
millimeter 
degrees. 
Same in 
grammes of 
water. 
Diffusate 
in grammes. 
Previous 
maceration. 
Hydrostatic 
resistance. 
Temperature, 
Fahr. 
per cent. 
day. 
min. 
2 
449 
21-883 
0-324 
1 
16 
66 
2 
484 
23-621 
0-400 
1 
16 
68 
10 
619 
30-178 
2-764 
1 
16 
68 
10 
595 
28-993 
3-150 
1 
12 
68 
In the double membrane, the average osmose of the 2 per cent, solution is reduced 
to 466 ms., from 665 ms. in the single membrane. The change is similar in the 
10 per cent, solution, namely a reduction to 607 from 896 ms. ; a reduction of nearly 
one-third of the osmose in the double membrane for both proportions of salt. 
The difference of the diffusates is much less marked ; for they may be said to be the 
same for the 10 per cent, solutions, namely 2’966 grammes in the single, and 2'957 
grammes in the double membrane ; and for the 2 per cent, solution 0*53 1 gramme in the 
single, and 0'326 gramme in the double membrane. The diffusion of carbonate of 
potash, as seen here in membrane, will be found to correspond well with that of chloride 
of sodium (Table VII.), as the diffusion of the same two salts in open vessels is known 
to present a near approach to equality. The great osmose or current of fluid inwards 
might be supposed to diminish the outward movement of the salt under diffusion by 
washing back the salt into the osmometer. But the diffusates of the 10 per cent, 
solutions appear to have suffered no remarkable reduction from that or any other 
cause. The diffusate of carbonate of potash, which usually passes through mem- 
brane, appears, however, to be low. In the 1 per cent, solution, formerly referred to 
(page 188), it was 0T95 gramme. In the series of observations, likewise already 
