PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
15 
of mixed salt in the three experiments. The analysis of the last product of 18T3 grs. 
gave — 
Carbonate of soda 5’68 31*33 
Chloride of sodium 12*45 68*67 
18*13 100*00 
Here the carbonate of soda presents a diffusion less than one-half of that of chlo- 
ride of sodium. The difference is again greater than the peculiar diffusibilities of 
the same salts as they appear when the salts are separately diffused. For in experi- 
ments made in the same phials with solutions of 4 parts of each salt singly to 100 
water, but with a lower temperature by 3°*6, namely, at 54°*3, the diffusion product 
of the carbonate of soda was 7" 17 and 7'34 grs. in two experiments, of which the 
mean is 7’25 grs.; while the diffusion product of the chloride of sodium was 11*18 
and 10*73 grs. in two experiments, of which the mean is 10*95 grs. The quantity of 
chloride of sodium diffused being taken at 100 in both sets of experiments, we have 
diffused — 
Of carbonate of soda 66*18, when diffused singly. 
Of carbonate of soda 45*64, when diffused with chloride of sodium. 
The least soluble of the two salts appears in all cases to have its diffusibility 
lessened in the mixed state. The tendency to crystallization of the least soluble salt 
must evidently be increased by the admixture. Now it is this tendency, or perhaps 
more generally the increased attraction of the particles of a salt for each other, 
when approximated by concentration, which most resists the diffusion of a salt, and 
appears to weaken the diffusive force in mixtures, as it is also found to do so in a 
strong solution of a single salt. 
(4.) Equal weights of nitrates of potash and ammonia dissolved, as in certain pre- 
ceding experiments, in five times the weight of the mixed salts of water, and diffused 
for eight days, gave in two experiments — 
At 59°-4. At 52°-6. 
Nitrate of potash 28*39 25*88 
Nitrate of ammonia .... 36*16 30*36 
64*55 56*24 
The inequality in the diffusion of these two nitrates is singular, considering that 
in solutions of 1 salt to 10 water, they appeared before to be equally diffusive. 
But on now comparing the diffusion of solutions of 1 salt to 5 water, at 52°*6, the 
salts no longer diffused in equal proportions ; — 
Nitrate of potash gave .... 57'93 grs. 
Nitrate of ammonia gave . . . . 82*08 grs. 
The solution of nitrate of potash last diffused was nearly a saturated one, while 
that of nitrate of ammonia is far from being so. The first has its diffusibility, in 
consequence, impaired, and falls considerably below the second. 
