174 
ON THE DIFFUSION OF LIQUIDS. 
potassium. The nitrate of potash, chlorate of potash,nitrate 
of ammonia,chloride of potassium,and chloride of ammonium 
formed another equi-diffusive group. The times in which 
an equal amount of diffusion took place in these two groups 
appeared to be as 1 for the second to 1.4142 for the first,or 
as 1 to the square root of 2. Now, in gases, the squares of the 
times of equal diffusion are the densities of the gases. The 
relation between the sulphate of potash and nitrate of potash 
groups would therefore fall to be referred to the diffusion 
molecule and diffusion vapor of the first group having a 
density represented by 2, while that of the second group is 
represented by 1. These were named the solution densities 
of the salts in question. The corresponding salts of sodaap- 
peared to fall into a nitrate and sulphate group also, which 
have the same relation to each other as the potash salts. 
The relation of the salts of potash to those of soda in times of 
equal diffusibility appeared to be as the square root of 2 to 
the square root of 3 ; which gives to them solution densities 
of 2 and 3. Hydrate of potash and sulphate of magnesia 
were less fully examined ; but the first presented sensibly 
double the diffusibility of sulphate of potash, and four 
times the diffusibility of the sulphate of magnesia. If these 
times are all squared, the following remarkable ratios are 
obtained for the solution densities of these different salts, 
each of which is the type of a class of salts : hydrate of 
potash 1, nitrate of potash 2, sulphate of potash 4, 
sulphate of magnesia 16, with nitrate of scda 3, and 
sulphate of soda 6. In conclusion, it was observed that 
it is the diffusion molecules of the salts, having such den- 
sities, which are concerned in solubility; and not the Dalto- 
nian atoms or equivalents of chemical combination ; and 
the application was indicaied of a knowledge of the diffusi- 
bilities ofdifferent substances to the study of endosmose, in 
which the proper function of the membrane would be dis- 
tinguished from that ofthe salt.— Pharm. Jour. Feb. 1850. 
