212 
PROFESSOR GRAHAM ON OSMOTIC FORCE. 
Table XIX. — Solutions in Osmometer Q of albuminated calico for five hours. 
Salt in osmometer. 
Rise in 
millimeter 
degrees. 
Temperature, 
Fahr. 
Sulphate of potash, 1 per cent 
18 
O 
53 
Same 
21 
57 
Sulphate of potash, 1 per cent. + carbonate of potash, 0*01 per cent 
139 
62 
Same + same 
81 
56 
Same + same 
73 
6l 
Same + carbonate of potash, 0-1 per cent 
254 
61 
Same + same 
263 
59 
Carbonate of potash, 04 per cent., alone 
92 
57 
Carbonate of potash, 0-1 per cent., alone 
95 
57 
Sulphate of soda, 1 per cent. + carbonate of potash, 04 per cent 
257 
62 
Same + same 
237 
54 
Same + carbonate of soda, 04 per cent 
299 
54 
Carbonate of soda, 04 per cent., alone 
90 
57 
Same 
127 
58 
The influence of the two alkaline carbonates in giving a high osmose to the sul- 
phates, appears to be pretty nearly equal. The primary source of the great osmose 
may prove to be the action on membrane of the alkaline carbonates, which is pro- 
moted in some way by the presence of sulphate of potash, as it is retarded by the 
presence of chloride of sodium. 
On the other hand, the moderate amount of osmose which appears to be proper to 
these sulphates is completely negatived by the most minute addition of a strong acid. 
Thus, 1 per cent, of sulphate of potash, with the addition of one ten-thousandth part 
(0*01 per cent.) of hydrochloric acid, had its osmose reduced, in the first experiment 
to 8 ms., and in the second experiment to —5 ms., the osmose becoming actually 
negative. 
On one occasion, a specimen of well-crystallized sulphate of potash gave, when 
dissolved, a still more sensible negative osmose, namely —28 ms. On applying litmus 
to the solution, it was found to possess an acid reaction. But the addition of 0‘01 
per cent, carbonate of potash was sufficient to change the acid into an alkaline 
reaction, and to give rise to a positive osmose, amounting to 54 ms. 
It occurred to me to macerate a fresh membrane in water, containing one-thousandth 
part (0 - l per cent.) of hydrochloric acid, for two days, before applying the membrane 
to the osmometer, and then to wash the membrane with distilled water till all acid 
reaction disappeared. With 1 per cent, of neutral sulphate of potash, this membrane 
gave in succession 17, 42, 35 and 62 ms.; with sulphate of soda, 1 per cent., follow- 
ing, 39, 25 and 25 ms. ; and with sulphate of zinc (anhydrous), 1 per cent., after the 
last salt, 14 and 21 ms. These last results show a certain degree of unsteadiness in 
the osmose of the alkaline sulphates, probably arising from the osmose of these salts 
depending so much upon adventitious circumstances. The diffusates were carefully 
weighed, first when fully dried, at 212°, and again when ignited. The difference in 
