PROFESSOR GRAHAM ON OSMOTIC FORCE. 
221 
Table XXV. — Solutions of 1 percent, of Salts of Lead in Osmometei M of double 
membrane for five hours. 
Salt in solution. 
Rise in 
millimeter 
degrees. 
Hydrostatic 
resistance. 
Temperature, 
Fahr. 
Nitrate of lead 
174 
min. 
2 
64 
Same 
21 1 
2 
65 
Same 
197 
2 
62 
Acetate of lead 
100 
2 
64 
Same 
97 
2 
61 
The numbers which these results appear to authorize, were for acetate of lead 
97 ms., and for nitrate of lead 204 ms. (mean of 211 and 197 ms.). The acetate 
exhibits, as usual, a considerably inferior osmose to the nitrate of the same base. 
It appeared desirable to ascertain the osmose of higher proportions of a salt, which, 
like the nitrate of lead, exhibits decided osmose in the 1 per cent, solution. The 
first results appearing low, the membrane was washed with ether after the third 
experiment, a treatment of the membrane which in this instance sensibly improved 
its osmotic power. 
Table XXVI. — Solutions of Nitrate of Lead in Osmometer K of double membrane 
for five hours. 
Proportion 
of salt 
in solution. 
Rise in 
millimeter 
degrees. 
Same in 
grammes 
of water. 
Diffusate in 
grammes. 
Previous 
maceration. 
Hydrostatic 
resistance. 
Temperature, 
Fahr. 
per cent. 
1 
91 
0 
min. 
2 
61 
1 
127 
1 
1 
64 
1 
125 
1 
1 
63 
1 
157 
3 
8 
63 
1 
157 
9 
12 
63 
2 
184 
1 
12 
63 
2 
195 
1 
12 
66 
5 
209 
1 
12 
66 
5 
229 
1 
12 
67 
10 
213 
1 
12 
C9 
10 
250 
10-56 
3-283 
2 
16 
72 
These experiments lead to the estimation of the osmose of nitrate of lead as fol- 
lows : — in the 1 per cent, solution an osmose of 157 ms., in the 2 per cent, solution 
195 ms., in the 5 per cent, solution 229 ms., and in the 10 per cent, solution 250 ms. 
This, it is to be observed, is but a small increase for the higher proportions of salt. 
The diffusate for the 10 percent, solution of this salt may be considered of an average 
proportional amount. The replacing water then exceeds the salt diffused only about 
three and a half times. 
It is curious that the hydrostatic resistance of the membrane increases so decidedly 
as the experiments advance, in the osmose of this and several other metallic salts, 
