PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
811 
5. Sulphuric Acid. 
That time of diffusion arbitrarily chosen for this acid was ten days. The diffusate 
of this acid was determined in the same manner as that of nitric acid. 
1. Sulphate of water (HO.SO3), 0993 per cent.; density T0065. Diffused at 
51 °' 7 , in eight cells, 8’87, 8'87, 8'87j 8’69 ; mean 8*82 grs. of sulphate of water for 
two cells. Calculated for 1 per cent,, 8'91 grs. at 51°‘7 for two cells, and 8‘69 grs. 
at 49°'7. 
2. Sulphate of water, r89 per cent.; density T0130. Diffused at 49°'7 j in eight 
cells, 16T3, 16T6, 15'58, 16‘03 ; mean 15‘98 grs, for two cells. Calculated for 2 per 
cent., 16’91 grs, at 49°’7 for two cells. 
3. Sulphate of water, 2 per cent. ; density TO 133. Diffused at 63°'5, in eight cells, 
19'80, 20'05, 19‘67, 19‘41 ; mean 19'73 grs. for two cells. 
4. Sulphate of water, 3'87 percent.; density T0261. Diffused at 49°’7, in eight 
cells, 32'72, 32*72, 33*06, 32*58 ; mean 32*77 gi’S. for two cells. Calculated for 4 per 
cent., 33*89 grs. at 49°*7 for two cells. 
5. Sulphate of water, 7‘90 per cent.; density T0513, Diffused at 49°*7, in four 
cells, 34*08, 34*76, 33*74, 33*63 : mean 34*05 grs. for one cell. Calculated for 8 per 
cent,, 34*48 grs. at 49°*7 for one cell. 
In the 2 per cent, solution the diffusion rises, with the difference of temperature 
between 49°*7 and 63°*5, from 16*91 to 19*73 grs., or from 100 to 116*68, This is an 
increase of 1**209 per cent, for one degree of temperature. 
The diffusion of the different proportions of sulphuric acid is as follows — 
Diffusion of Sulphate of Water in ten days at 49°*7 ; two cells. 
Grs. 
Ratio. 
From 1 per cent, solution .... 
8*69 
1*03 
From 2 per cent, solution .... 
. 16*91 
2 
From 4 per cent, solution .... 
. 33*89 
4*01 
From 8 per cent, solution .... 
. 68*96 
8*16 
The diffusibility of different strengths of this acid appears to be pretty uniform, but 
with a slight tendency to increase in the higher proportions, like hydrochloric acid. 
Sulphuric acid is greatly inferior in velocity of diffusion to hydrochloric acid, but 
still appears to possess considerably more than half the diffusibility of the latter. 
6. Chromic Acid. 
Time of diffusion ten days. The diffusates from four cells of the 2 per cent, solu- 
tion were mixed together, and the quantity of chromic acid diffused for two cells re- 
duced by means of hydrochloric acid and alcohol, and weighed as oxide of chromium. 
1*762 per cent, of anhydrous chromic acid, density 1*01404, diffused at 67°*3, gave 
19*78 grs, of chromic acid in two cells. Calculated for 2 per cent., 22*43 grs. of 
chromic acid, in two cells, at 67°’3. The diffusion of sulphuric acid at 63°*5, was 
19 73 grs., which would give about 21 grs. of that acid at 67°'3. 
5 L 2 
