812 
PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
7 . Acetic Acid. 
Time of diffusion ten days. This acid cannot be determined accurately by the 
acidimetrical method, owing to the acetates of potash and soda being essentially 
alkaline to test-paper, like the carbonates of the same bases, although neutral in 
composition. The weight of carbonate of baryta dissolved by the acid was had re- 
course to. 
1. Acetate of water (HO.C4H3O3), 2 per cent. ; density T0030. Diffused at 48°'8, 
in eight cells, 12‘62, 10’94, ITIO, 1T39 grs. of acetate of water; mean 1T51 grs. for 
two cells. 
2. Acetate of water, 4 per cent. ; density T0060. Diffused at 48°'8, in eight cells, 
22*12, 2T71j 21*59, 22*67 ; mean 22*02 grs. for two cells. 
3. Acetate of water, 8 per cent.; density TOII 7 . Diffused at 48°*8, in four cells, 
21*19,20*13,21*84, 20*44 ; mean 20*90 grs. for one cell. The diffusion of the different 
proportions of acetic acid is as follows : — 
Diffusion of Acetate of Water in ten days at 48°*8 ; two cells. 
Grs. 
Ratio. 
From 2 per cent, solution . 
.... 11*31 
2 
From 4 per cent, solution . 
.... 22*02 
3*83 
From 8 per cent, solution . 
.... 41*80 
7*26 
The diffusibility diminishes with the larger proportions of acid. This acid appears 
to be considerably less diffusive than sulphuric acid. I was led to over-estimate the 
diffusion of acetic acid in a preliminary observation of my former paper, by trusting 
to the acidimetrical method of determination. Hydrochloric acid appears to diffuse 
about two and a half times more rapidly than acetate of water, at the same tempe- 
rature. 
8. Sulphurous Acid. 
The time of diffusion chosen for this acid was ten days, for comparison with 
sulphuric acid. 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 proportional quantity of liquid 
representing two eells in the 1 and 2 per cent, solutions, and 1 cell in the 4 and 8, 
was converted into sulphuric acid by a slight excess of bromine, and determined from 
the sulphate of baryta. 
1. 0*982 per cent, of sulphurous acid, density 1*0056, diffused at 68°*1, gave 
7*94 grs. in two cells. Calculated for 1 per cent., 8 09 grs. of sulphurous acid in 
two cells at 68°*1. 
2. 1*965 per cent, of sulphurous acid, density 1*01055, diffused at 68°*1, gave 
16*66 grs. for two cells. Calculated for 2 per cent., 16*96 grs. of sulphurous acid in 
two cells at 68°*1. 
3. 3*93 per cent, of sulphurous acid, density 1*01991, diffused at 68°*1, gave 
