PROFESSOR GRAHAM ON OSMOTIC FORCE. 
215 
Table XXI. — Oxalate and Chromates of Potash in Osmometer K of albuminated 
calico. 
Solution of salt. 
Rise in 
millimeter 
degrees. 
Diffusate in 
grammes. 
Previous 
maceration. 
Hydrostatic 
resistance. 
Temperat 
Fahr 
days. 
min. 
195 
1 
15 
65 
173 
1 
15 
65 
91 
1 
15 
63 
100 
2 
20 
60 
161 
8 
15 
56 
211 
1 
15 
60 
109 
1 
15 
62 
120 
1 
15 
68 
195 
1 
15 
62 
188 
2 
15 
55 
36 
0-244 
1 
15 
54 
34 
2 
10 
56 
129 
0-253 
1 
10 
62 
123 
0-242 
1 
10 
58 
95 
0-251 
2 
10 
57 
102 
0-320 
1 
10 
60 
1 per cent, oxalate of potash 
Same 
(H per cent, oxalate of potash 
Same 
1 per cent, oxalate of potash +(H per cent 
carbonate of potash 
Same + same 
(H per cent, carbonate of potash 
Same 
1 per cent, oxalate of potash + 0-1 per cent. \ 
carbonate of potash J 
Same + same 
1 per cent, bichromate of potash 
Same 
1 per cent, chromate of potash 
Same 
1 per cent, chromate of potash +0-1 per "I 
cent, bichromate of potash J 
Same 
The average rise for the 1 per cent, solution of each of the salts is, for bichromate 
of potash 35 ms., for chromate of potash 126 ms., and for oxalate of potash 184 ms., 
all a little higher than in the previous membrane osmometer. The diffusate is lower 
than before, probably owing to the less permeability of the albuminous septum, the 
weight of chromate of potash diffused being 0'2475 gramme, and of bichromate of 
potash 0 - 244 gramme. 
The two chromates have been found to possess nearly equal diffusibility in open 
vessels, and to correspond closely in that property with sulphate of potash. The 
oxalate of potash exhibits a considerable osmose when present in the small proportion 
of one-thousandth part (O’l per cent.), namely 91 ms. in membrane and 95'5 ms. 
in albumen. This is the surest indication of considerable osmotic capacity. Bin- 
oxalate of potash and free oxalic acid are both remarkable for high negative osmose. 
Barium , Strontium, Calcium, Magnesium. — The salts of these metals never appear 
capable of producing strong positive osmose when dissolved in a proportion of less 
than 1 per cent. On the contrary, some of the salts of this class, particularly the 
nitrates, exhibit a tendency to negative osmose. 
Hydrate of Baryta gave a small positive osmose for minute proportions of salt, 
which disappeared as the proportion of salt was increased, exhibiting an analogy in 
this respect to hydrate of potash. The results for hydrate of baryta in double mem- 
brane were 6, 4, 1 and 1 degrees of osmose for the OT, 0'25 and 0'5 per cent, solu- 
tions. In albumen the same solutions gave 0, —8, —23 and —17 ms.; and the 
1 per cent, solution gave —25 ms. 
