IVIE. T. GEAHAM 01^ LIQIHP DIEEUSION APPLIED TO ANALYSIS. 199 
of the following salts at two different temperatures appeared to be, — 
For chloride of potassium at 5°-3 (41°-5 F.), 1 ; at 16°'6 (62° F. ), 1’4413 
For chloride of sodium at 5°-3 (41°-5 F.), 1 ; at 17°-4 (63°*4 F.), 1-4232 
For nitrate of soda at 5°-3 (41°-5 F.), 1 ; at 17°-4 (63°-4 F.), 1-4475 
For nitrate of silver at 5°-3 (41°-6 R), 1 ; at 17°-4 (63°-4 R), 1-3914. 
The salts are unequally affected to a sensible extent ; and it will be observed that the 
superiority of chloride of potassium over chloride of sodium, in diffusibility, is increased 
at the low temperature. 
'Within the range of temperature of the preceding experiments, the diffusibility of 
chloride of sodium being taken as 1 at 17°-4 (63°-4 F,), it becomes 0-7026 at 5°-3 (41°-5 F.}; 
or it diminishes 0-0246, or 47 ^, for a depression of 1° (0-0136, or for a depression 
ofFR). 
3. Dialysis. 
Passing from liquid difftision in the water-jar, I may advert first to the diffusion of 
cr)'stalloids through a gelatinous or colloid mass, the circumstance of the experiment 
being varied as little as possible fi-om those of jar-diffusion. 
Ten grammes of chloride of sodium and 2 grammes of the Japanese gelatine, or gelose 
of Patex, were dissolved together in so much hot water as to form 100 cub. cents, 
of fluid. Introduced into the empty diffusion-jar and allowed to cool, this fluid set into 
a Arm jelly, occupying the lower part of the jar, and containing of course 10 per cent, 
of chloride of sodium. Instead of placing pure water over this jelly, it was covered by 
700 cub. cents, of a solution containing 2 per cent, of the same gelose, cooled so far as 
to be on the point of gelatinizing; the jar at the same time being placed in a cooling 
mixture, in order to expedite that change. The jar with its contents was now left 
undisturbed for eight days at the temperature 10°. After the lapse of this time the 
jelly was removed from the jar in successive portions of 60 cub. cents, each from the 
top, and the proportion of chloride of sodium in the various strata ascertained. The 
results were very similar to those obtained in diffusing the same salt in a jar of pure 
water. The diffusion in the gelose appeared more advanced in eight days than diffusion 
in water for seven days, as will be seen by comparing the gelose experiment below with 
a water experiment on chloride of sodium which had been conducted at nearly the same 
temperature (Table III.}. 
