824 
PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
29. Sulphate of Alumina. 
The time of diffusion chosen was 16*166 days, or the same as that for sulphate of 
magnesia. The usual number of eight cells of the 1 and 2 per cent, solutions were 
diffused, and four cells of the 4 and 8 per cent, solutions. The whole diffusates of 
each proportion were then mixed together and the quantities of alumina and sulphuric 
acid, diffused for two ceils, determined separately. 
]. T045 per cent, of sulphate of alumina, density T01160, diffused at 65”*4, gave 
1*80 gr. of alumina and 3*93 grs. of sulphuric acid, in all 5*73 grs. for two cells. Cal- 
culated for 1 per cent., 1*72 gr. alumina and 3*76 grs. sulphuric acid, in all 5*48 grs. 
of sulphate of alumina in two cells at 65°*4. 
2. 2*091 per cent, of sulphate of alumina, density 1*02251, diffused at 65°*4, gave 3*32 
grs. of alumina and 7’35 grs. of sulphuric acid, in all 10*67 grs. for two cells. Calcu- 
lated for 2 per cent., 3*18 grs. of alumina and 7'03 grs. of sulphuric acid, in all 10*21 
grs. of sulphate of alumina for two cells at 65°*4. 
3. 4* 182 per cent, of sulphate of alumina, density 1*0438, diffused at 65°*4, gave 3*17 
grs. of alumina and 6*91 grs. of sulphuric acid, in all 10*08 grs. for one cell. Calcu- 
lated for 4 per cent., 3*03 grs. of alumina and 6*61 grs. of sulphuric acid, in all 9*64 
grs. of sulphate of alumina for one cell at 65°*4. 
4. 8*364 per cent, of sulphate of alumina, density 1*08518, diffused at 65°*4, gave 
5*37 gi’S. of alumina and 12*15 grs. of sulphuric acid, in all 17'52 grs. for one cell. 
Calculated for 8 per cent., 5*14 grs. of alumina and 11*62 grs. of sulphuric acid, in 
all 16*76 grs. of sulphate of alumina for one cell at 65°*4. 
Diffusion of Sulphate of Alumina in 16*166 days at 65°*4 ; two cells. 
Grs. 
Ratio. 
From 1 per cent, solution . 
. . 5*48 
1*074 
From 2 per cent, solution . 
. . 10*21 
2 
From 4 per cent, solution . 
. . 19*28 
3*780 
From 8 per cent, solution . 
. . 33*52 
6*572 
The diffusion of sulphate of alumina, it will be observed, is very sensibly less than 
that of sulphate of zinc at the same temperature. 
30. Nitrate of Silver. 
Time of diffusion seven days. The quantity of salt diffused was ascertained by 
precipitation with hydrochloric acid, and weighing the chloride of silver formed. 
1. Nitrate of silver, 0*996 per cent. ; density 1*0089. Diffusion at 51°*4, in eight 
cells, 5*39, 5*39, 5*74, 5*50 ; mean 5*50 grs. for two cells ; calculated for 1 per cent., 
5*52 grs. at 51°*4 for two cells. 
2. Nitrate of silver, 1*98 per cent. ; density 1*0161. Diffusion at 53°, in eight cells, 
11*27, 11*16, 11*05, 11*06; mean 11*13 grs. for two cells; calculated for 2 percent., 
1 T24 grs. at 53° for two cells. 
