814 
PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
Ammonia appears to have a diffusibility approaching to that of hydrate of potash. 
It appears somewhat less diffusive than hydrocyanic acid at the same temperature, 
in the proportion of 12 to 13 nearly; or to possess about three-fourths of the diffusi- 
bility of hydrochloric acid. 
10. Alcohol. 
Time of diffusion ten days. The quantity of alcohol diffused was determined by 
careful distillation. 
1. Alcohol, 2 per cent. ; density made up to r0237 with chloride of sodium. Diffused 
at 40°‘7, in eight cells, 17‘80, 16'70; mean 17’25 grs. for four cells, or 8‘62 grs. for 
two cells. 
2. Alcohol, 4 per cent. ; density made up to 1 '0203 with chloride of sodium. Diffused 
at 48°‘75 in eight cells, 34*30, 30*20 ; mean 32*25 grs. for four cells, or 16*12 grs. for 
two cells. 
3. Alcohol, 8 per cent. ; density made up to 1*0154 with chloride of sodium. Diffused 
at 48°*7, in four cells, 30*80, 40*2 ; mean 35*50 grs. for two cells, or 17’75 grs. for one 
cell. 
The results accord less closely with each other than usual, owing, I believe, chiefly 
to the difficulties of manipulation when the density of the liquid placed in the phials 
to be diffused approaches so nearly to that of water. This is more particularly true 
of the 8 per cent, solution. 
Diffusion of Alcohol in ten days at 48°*7 ; two cells. 
From 2 per cent, solution 8*62 
From 4 per cent, solution 16*12 
From 8 per cent, solution 35*50 
It would be unsafe to draw any conclusion as to the proportionality of the diffusion 
of alcohol to the strength of the solution from these experiments. 
Alcohol does not appear to belong to the same class of diffusive substances as acetic 
acid, which might be expected from their similarity of composition, but possesses a 
considerably lower diffusibility. 
Diffusion from 2 per cent, solutions in ten days. 
Acetate of water at 4 8°*8 . . . 11*51 100 
Alcohol at 48°*7 8*62 74 9 
The diffusion of alcohol approaches to one-half of that of sulphate of vv^ater at 
nearly the same temperature, p. 811. 
Alcohol may be substituted for water to dissolve certain salts, and also as an atmo- 
sphere into which these salts may diffuse. From experiments which have been com- 
menced on this subject, it appears that the diffusion of hydrate of potash, iodide of 
potassium, chloride of calcium and others is about four times slower into alcohol 
of density 0 840 than into water. The salts likewise often exhibit the same rela- 
