PROFESSOR GRAHAM ON OSMOTIC FORCE. 
219 
To learn whether this arose from the passage of iron into the higher oxide or not, 
sulphurous acid and hydrosulphuric acid were mixed with the protochloride of iron, 
but, as will be seen below, without lessening the osmose. 
Table XXIII. — One per cent. Solutions of several Magnesian Chlorides in 
Osmometer F of double membrane for five hours. 
Salt in osmometer. 
Rise in 
millimeter 
degrees. 
Hydrostatic 
resistance. 
Temperature, 
Fahr. 
Chloride of magnesium 
3 
min. 
2 
O 
59 
Chloride of zinc 
48 
2 
61 
Same 
54 
2 
62 
Chloride of manganese 
24 
1-75 
62 
Same 
34 
1-5 
63 
Protochloride of iron 
160 
1 
6l 
Same 
197 
435 
1 
64 
Same 
2 
65 
Protochloride of iron + Ol per cent, sulphurous acid ... 
404 
4 
62 
Protochloride of iron saturated with SH 
332 
4 
64 
Protochloride of iron, alone 
155 
4 
61 
The osmose of protochloride of iron is large, but singularly unsteady in amount, 
rising from 160 to 435 ms., and falling again to 155 ms. 
In another double membrane, of rather small resistance (1 min.), the osmose of 
the same salt was only 94, 91 and 9 7 ms. Between the first and second of these 
experiments the membrane was washed with alcohol and ether, but without changing 
the character of the osmose. In experiments made with this last membrane, the 
2 per cent, solution of protochloride of iron gave 151 and 157 ms.; and the 5 per cent, 
solution 189 ins., or the osmose did not rise in proportion to the quantity of salt in 
solution. 
Nitrate of Sesquioxide of Iron, formed by saturating dilute nitric acid by hydrated 
sesquioxide of iron, gave, in single membrane, the high osmose of 322 and 359 ms. 
for one per cent, of salt ; and 153, followed by 107 ms., for 0T per cent, of salt. The 
acetate of the same oxide gave, when of a deep red colour, 207 ms., and when it had 
become nearly colourless, from the spontaneous precipitation of a portion of its oxide, 
194 ms., or sensibly the same osmose. 
Manganese . — Sulphate of manganese appeared to have no decided chemical 
osmose, giving in double membrane of moderate resistance (2 min.), for 1 per cent, 
of salt, 34, 51 and 50 ms. ; for 4 per cent, of salt, 53 and 51 ms., and for 10 per cent, 
of salt, 57 and 59 ms. The low osmose of the larger proportions of this salt is excep- 
tional and would require confirmation. 
The chloride of manganese has already been shown to be of low osmose in mem- 
brane (24 and 34 ms. Table XXIII.); in albumen the same salt gave 13 and 14 ms. 
Cobalt . — The chloride of this metal appeared to possess no decided chemical 
2 f 2 
