12 
PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS, 
Table V. — Diffusion of acid solutions (4 acid to 100 water) at 59°‘3. 
Name of acid. 
Density of 
solution at 60°. 
Anhydrous acid diffused. 
In grains. 
Means. 
Nitric acid 
1*0243 
29*21 
28*19 
28*7 
Hydrochloric acid 
1*0225 
34*22 
33*99 
34*1 
Sulphuric acid 
1*0317 
18*71 
18*26 
18*48 
Acetic acid 
1*0094 
19*13 
17*19 
18*16 
Oxalic acid 
1*0235 
12*38 
12*38 
12*38 
Arsenic acid 
1*0320 
12*16 
12*16 
12*16 
Tartaric acid 
1*0194 
9*90 
9*69 
9*79 
Phosphoric acid 
1*0284 
9*09 
9*09 
9*09 
Chloride of sodium 
1*0285 
12*32 
12*32 
Considerable latitude thus appears to exist in the diffusibility of the different acids. 
To make the result for nitric acid fairly comparable with that for liydrochloric acid, 
the former should be increased in the proportion of 54 to 63, that is estimated as 
nitrate of water. This calculation gives 33'5 grs. of nitrate of water diffused, which 
approaches closely to 34' 1 grs., the quantity for chloride of hydrogen or hydrochloric 
acid. The quantity of soda neutralized by the sulphuric and hydrochloric acids dif- 
fused was as 14‘32 to 28'97, or nearly as 1 to 2. Sulphuric and acetic acids, on the 
other hand, appear to be equally diffusible. Phosphoric acid is the least diffusible 
acid in the series, presenting only about half the diffusion product of the two last- 
mentioned acids. The solution of phosphoric acid had been boiled for half an hour 
before diffusion, and was therefore in the tribasic state. The same precaution was 
not thought of for arsenic acid, although it is possibly required by this acid also. 
These two acids do not exhibit the equality of diffusion anticipated from their recog- 
nized isomorphism, but it is to be stated that the acidirnetrical method of analysis 
followed is not so properly applicable to these two acids as it is to all the others. 
3. Diffusion of Ammomated Salts of Copper. 
It was interesting to compare together such related salts as sulphate of copper, the 
ammoniated sulphate of copper or soluble compound of sulphate of copper with 
2 equivs. of ammonia and the sulphate of ammonia. It is well known that metallic 
oxides, or subsalts of metallic oxides, when dissolved in ammonia or the fixed alkalies, 
are easily taken down by animal charcoal. This does not happen with the ordinary 
neutral salts of the same acids, which are held in solution by a strong attraction. 
Supposing the existence of a scale of the solvent attraction of water, the preponde- 
rance of the charcoal attraction will mark a term in that scale. And if the solvent 
