PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
5 
depth of an inch with water, which required about 30 ounces of the 
Jatter, fig-. 2. The saline solution in the diffusion cell or phial thus 
communicated freely with about 5 times its volume of pure water, the 
liquid atmosphere which invites diffusion. Another modification of 
this procedure was the substitution of phials cast in a mould, of the 
capacity of 4 ounces, or more nearly 2080 grs., which were ground 
down to a uniform height of 3-8 inches. The neck was T25 inch in 
diameter and 0-5 inch in depth ; and the phial was filled up with the 
solution to be diffused to that point. The solution cell or phial and the water-jar 
form together a Diffusion cell. 
The diffusion was stopt, after twenty-seven days in the present experiments, by 
closing the mouth of the phial with a plate of glass, and then raising it out of the 
water-jar. The quantity of salt or of acid which had found its way into the water- 
jar, — the diffusion product as it maybe called, — was then determined by evaporating 
to dryness for the salts, and by neutralizing the same liquid with a normal alkaline 
solution for the acids. The quantities of the acids diffused are estimated at present 
as protohydrates for the sake of comparison with the salts. 
Fig. 2. 
11 
1 
Table I. — Diffusion of Solutions of Density T200. Temp. 66° Fahr. 
Placed ill solution cell. 
Found in water-jar. 
Proportion of anhy- 
drous salt, or of acid 
protohydrate, to 100 
of water. 
Boiling- 
point. 
Diffusion product. 
In grains. 
Ratio. 
Chloride of sodium 
34*21 
225*5 
269-80 
100 
Nitric acid 
37*93 
227 
581*20 
215*42 
Sulphuric acid 
29*03 
223 
455*10 
168*68 
Chloride of potassium (density 1*178)... 
34*86 
221 
320*30 
118*71 
Bisulphate of potash 
31*85 
216 
319*00 
118*23 
Nitrate of soda 
32*42 
220 
260*20 
96*44 
Sulphate of magnesia 
22*38 
214 
95*87 
35*53 
Sulphate of copper 
21*56 
2131 
77*47 
28*71 
It appears that the diffusion from solutions of the same density is not equal but 
highly variable, ranging from 1 to O' 1333. 
The results also favour the existence of a relation between large or rapid diffusibi- 
lity and a high boiling-point. The latter property may be taken to indicate of itself 
a high degree of attraction between the salt and water. 
