222 
PROFESSOR GRAHAM ON OSMOTIC FORCE. 
particularly nitrates. It is not to be supposed, however, that this change has any 
material influence upon the osmose. 
Uranium . — The nitrate of uranium presented a high degree of osmose. This 
result scarcely affects the question of the constitution of the metallic oxide present 
in that salt, as a high osmose is exhibited, both by the salts containing an oxide of 
the type R 2 0 3 , and by a portion at least of the class of protoxides. Viewed as an 
aluminous salt the nitrate of uranium has a basic composition (Ur 2 0 3 N0 5 ), a 
circumstance which suggested the addition of free nitric acid to that salt in some 
experiments. The small proportion of one-tenth per cent, of nitric acid will be seen 
to have a moderate influence, and 1 per cent, of nitric acid to have an overpowering 
influence in reducing the extraordinary osmose of this salt. 
Table XXVII. — Solutions of Nitrate of Uranium in Osmometer M of double 
membrane for five hours. 
Proportion of salt in solution. 
Rise in 
millimeter 
degrees. 
Diffusate in 
grammes. 
Previous 
maceration. 
Hydrostatic 
resistance. 
Temperature, 
Fahk. 
1 per cent, nitrate of uranium 
288 
0-078 
days. 
1 
min. 
1 
60 
1 per cent, nitrate of uranium 
458 
0-102 
3 
i 
61 
Same + 1 per cent, nitric acid 
44 
0-205 
1 
i 
63 
Same + same 
70 
0-136 
1 
3 
66 
Same + (PI per cent, nitric acid 
304 
0-078 
1 
3 
62 
Same + same 
282 
0-108 
1 
3 
61 
The inferior osmose of the first observation in the Table arose from the osmose 
of the early hours of the experiment being less than ihose of the later hours, the 
osmose for the five hours in succession being 36, 46, 67, 77 and 63 ms. 
This progression, combined with the additional circumstance to be observed, that 
the diffusate is below the average in the same experiment, suggests the idea of an 
absorbing or retaining power in the membrane for the salt, which must first be satis- 
fied before the osmose and diffusion can proceed in a regular manner. 
The diffusate is throughout small, like that of an aluminous salt. 
In an albumen osmometer the osmose of the same salt was inconsiderable, namely 
49 and 53 ms.; but that osmose was not further reduced by the addition of nitric 
acid. 
Tin . — The protochloride of tin exhibits a high degree of osmose, like so many 
other metallic protochlorides. The one percent, solution gave, in double membrane, 
an osmose of 235, 253, 289 and 275 ms. The bichloride of tin following immediately 
in the same membrane gave only 27 ms. But the osmose of the bichloride of this 
metal is essentially negative, even when the salt is made as neutral in composition as 
possible. It has been already described (page 192). 
Antimony . — The double tartrate of potash and antimony proved rather remark- 
able for low osmose. 
