488 
PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
closely at the same temperature, the times of diffusion of the two substances being 
taken as 2 to 1. 
Sulphate of Soda . — Time of diffusion 9‘9 days. The diffusate was evaporated to 
dryness and weighed. 
1. One per cent, of sulphate of soda, density T00940, diffused at 59°‘9, in eight cells, 
6'31, 6'47, 6*21, 6‘32 ; mean 6'33 grs. for two cells. 
2. T995 per cent, of sulphate of soda, density TO 1832, diffused at 59°'9, in eight 
cells, 12'02, 12T0, 1T66, 12T6; mean lT98grs. for two cells; calculated for 2 per 
cent., 12’00 grs. of sulphate of soda in two cells at 59°'9. 
3. 3*99 per cent, of sulphate of soda, density T03594, diffused at 59°'9, in four cells, 
lO’OO, 10'80, 1T53, 1T53; mean 10’96grs. for one cell; ealculated for 4 per cent., 
10'98 grs. of sulphate of soda in one cell at 59°'9. 
4. 7'98 per eent. of sulphate of soda, density T06960, diffused at 59°’9, in four cells, 
20’50, 2T36, 20‘01, 20*68; mean 20*64 grs. for one cell; calculated for 8 per cent., 
20*69 grs. of sulphate of soda in one cell at 59°*9. 
Diffusion of Sulphate of Soda in 9’9 days at 59°*9 ; two cells. 
Grs. 
Ratio. 
From 1 per cent, solution . 
. . 6*33 
1*055 
From 2 per cent, solution . 
. . 12*00 
2 
From 4 per cent, solution . 
. . 21*96 
3*66 
From 8 per cent, solution . 
. . 41*38 
6*896 
The 2 per cent, solution of sulphate of soda above, at 59°*9, appears to be more 
diffusive than the corresponding solution of carbonate of soda at 59°*6, as 12*00 to 
10*65 grs., or as 100 to 88*75. 
The assumed relation in the times of equal diffusion for salts of potash and soda 
appears to derive support from the sulphates, particularly in the lower proportions 
of salt. 
Comparative Diffusion of Sulphate of Potash in 8*083 days at 60°*3, 
and Sulphate of Soda in 9*9 days at 59°*9. 
, From solutions of 
1 per cent. 
2 per cent. 
4 per cent. 
8 per cent. 
Sulphate of potash 
100 
102-74 
100 
103-45 
100 
96-74 
100 
94-21 
Sulphate of soda 
Another set of experiments made upon these two salts, simultaneously with certain 
oxalates and acetates which follow, may be placed here to illustrate the same relation. 
The preceding times of diffusion were observed. 
5. 2*013 per cent, of sulphate of potash, diffused at 59°*8, in eight cells, gave 11*90, 
1 1 *94, 11*41, 11*71 ; mean 1 1 *74 grs. for two cells ; calculated for 2 per cent., 1 1 *67 grs. 
of sulphate of potash in two cells. 
6. Two per cent, of sulphate of soda, density 1*01846, diffused at 59°*6, in eight cells, 
gave 11*58, 11*56, 11*94, 11*97; mean 11*76 grs. of sulphate of soda in two cells. 
