220 
PROFESSOR GRAHAM ON OSMOTIC FORCE. 
osmose, 1 percent, giving in double membrane 21 and 27 ms.; 0T per cent. 20 and 
23 ins., and 1 per cent, again 44 ms. 
Nickel . — The sulphate of oxide of nickel resembled that of magnesia and prot- 
oxide of iron. In double membrane 1 per cent, gave 12 and 10 ms.; 4 per cent. 
38 and 38 ms.; 10 per cent. 72 and 106 ms. 
The chloride of nickel, however, appeared to have a tendency to chemical osmose, 
like the protochloride of iron, and gave in double membrane 52,89 and 95 ms. 
Zinc . — None of the salts of this metal can be said to exhibit decided chemical 
osmose; sulphate of zinc giving 34 and 29 ms., nitrate of zinc 18 and 32 ms., and 
chloride of zinc 48 and 54 ms., all in double membrane. 
Cadmium. — The nitrate of cadmium appeared to affect chemical osmose ; the one 
per cent, solution of this salt giving, in double membrane, 90, 124 and 137 ms. 
Copper . — Copper appears to possess the capacity for chemical osmose in its 
salts generally, with the exception of the sulphate. But no sulphate appears to be 
remarkable for osmotic activity. The comparative osmose of four salts of copper in 
the same membrane is given below. 
Table XXIV. — Solutions of 1 per cent, of Salts of Copper in Osmometer E of 
double membrane for five hours. 
Salt in solution. 
Rise in 
millimeter 
degrees. 
Hydrostatic 
resistance. 
Temperature, 
Fahr. 
min. 
Chloride of copper 
351 
i 
60 
Sulphate of copper 
48 
10 
59 
Nitrate of copper 
154 
10 
60 
Same 
204 
12 
62 
Acetate of copper 
148 
10 
62 
Same 
102 
10 
63 
Same 
101 
10 
61 
The rate of osmose is generally a little deranged on passing from one salt to another 
in the same membrane, and in consequence the second or third experiment is always 
to be preferred to the first made with the same salt. The preferable numbers for the 
osmose of the preceding salts would therefore be, sulphate of copper 48 ms., acetate 
102, nitrate 204, and chloride 351. The number for the sulphate, however, is pro- 
bably too high, being raised by the previous chloride. 
The salts of several of the magnesian metals exhibit a much lower osmose in 
albumen than in membrane. In an osmometer of the first description nitrate of 
copper gave only 22 and 27 ms. ; acetate of copper 22 and 25 ins., or no more osmose 
than is obtained from the corresponding salts of lime and magnesia. 
Lead . — The salts of this metal are probably equally osmotic with those of copper. 
The nitrate and acetate of lead only were examined. The osmose of these two salts 
obtained in the same membrane was as follows : — 
