PROFESSOR GRAHAM ON OSMOTIC FORCE. 
217 
With 0*1 ]>er cent., rise of 510 ms. at 54° Fahr. 
With 0*1 per cent., rise of 285 ms. at 48° „ 
With 0‘1 per cent., rise of 410 ms. at 56° „ 
The numbers, which are all high, vary considerably among themselves, as often 
happens when osmose is intense and is observed in a single membrane. The tem- 
peratures of the water-jar are added in these and most other observations recorded, 
although it was difficult to draw any positive conclusion respecting the influence of 
heat upon the osmose of small proportions of salt. With large proportions of neutral 
salts, where diffusibility prevails, the osmose appeared to increase with the tempera- 
ture, as does the proportion of salt diffused. With respect to the condition of the 
membrane used above, the first experiment was conducted in the membrane freshly 
dissected and previous to any maceration or washing whatever, with a similar osmotic 
result, it will be observed, as in the later experiments made with the membrane after 
being repeatedly macerated. 
In experiments of diffusing chloride of aluminium in open vessels, decomposition 
of that salt was observed with escape of free hydrochloric acid. The decomposition 
appeared however to affect much less of the chloride of aluminium than it does of the 
acetate of alumina. 
In an albumen osmometer, chloride of aluminium gave an osmose of 245, 233 and 
229 ms., at 57°, 58° and 60°, with diffusates of 0*085, 0*123 and 0*095 gramme of salt, 
calculated from the quantity of chlorine found in the diffusate. 
In the last experiment the solution was coloured with litmus, apparently without 
affecting the amount of osmose. 
Acetate of Alumina was prepared by precipitating pure sulphate of alumina by 
means of the acetate of lead. Mr. Crum has shown that in this reaction one equi- 
valent of acetic acid becomes free, and that the acetate of alumina produced has 
the form AI 2 0 3 -(-2C 4 H 3 0 3 . A specimen of the pure binacetate, prepared by 
Mr. Crum, exhibited an equally high osmose as the salt mixed with free acid obtained 
by precipitation, which is used below. 
Table XXII. — Acetate of Alumina in Osmometer G 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. 
1 
232 
9*728 
days. 
2 
min. 
3-5 
65 
1 
264 
11-096 
1 
3-5 
65 
0-1 
195 
8-208 
1 
3-5 
64 
0*1 
130 
5-472 
0-036 
2 
3 
66 
0*1 
159 
6-688 
0-051 
1 
3 
67 
0-1 
146 
6-152 
0-045 
2 
3 
67 
2 F 
MDCCCLIV. 
