200 
ME. T. GEAHAM ON LIQUID DIFFUSION APPLIED TO ANALYSIS. 
Table XI. — Diffusion of a 10 per cent, solution of Chloride of Sodium 
in the jelly of gelose, for eight days, at 10°. 
Xuniber of 
stratum. 
Difiusate, 
in grammes.- 
1 
•015 
2 
•015 
3 
■026 
4 
•035 
5 
•082 
6 
•130 
7 
•212 
8 
•350 
9 
•486 
10 
•630 
11 
•996 
12 
M72 
13 
1-190 
14 
1-203 
15 and 16 
3-450 
9-992 
Diffusion of a crystalloid thus appears to proceed through a firm jelly with little or no 
abatement of velocity. With a coloured crystalloid, such as bichromate of potash, the 
gradual elevation of the salt to the top of the jar is beautifully illustrated. On the 
other hand, the diffusion of a coloured colloid such as caramel through the jelly, appears 
scarcely to have begun after eight days had elapsed. The diffusion of a salt into the 
solid jelly may be considered as cementation in its most active form. 
Numerous experiments were made on the diffusion of crystalloids through various 
dialytic septa, such as gelatinous starch, coagulated albumen, gum-tragacanth, besides 
animal mucus and parchment-paper, which all tended to prove how little the diffusive 
process was interfered with by the intervention of colloid matter. Salts appeared to 
preseiwe their usual relative diffusibility unchanged. The same partial separation of 
mixed salts was obseiwed as in the water-jar. With a mixture, for instance, of equal 
parts of chlorides of potassium and sodium in the dialyser, the first tenth part of the 
mixture which passed through was found to consist of 59 T 7 per cent, of chloride of 
potassium and 40 ’83 per cent, of chloride of sodium. Double salts also, such as alum, 
and the sulphate of copper and potash, which admit of being resolved into pairs of 
unequally diffusive salts, were largely decomposed upon the dialyser, as they are in the 
water-jar. The effect of heat in promoting diffusion appeared, however, to be diminished 
in dialysis, at least with a parchment-paper septum. Thus the diffusion from a 2 per 
cent, solution of chloride of sodium in a constant period of three hours was, — 
O 
Eatio. 
At 10 . 
. . 0-738 grm. 
1 
At 20 . 
. . 0-794 grm. 
1-07 
At 30 . 
. . 0-892 grm. 
1-20 
At 40 . 
. . 1-017 grm. 
1-37. 
