VII. ON SOLUBILITY. 847 
tion theory and the law of mass action. Their experimental results 
were found to be in fair agreement with the requirements of that theory. 
Dahms ** published a thermodynamical discussion which led him 
to results in support of the general law of solubility enunciated by 
Schréder and Le Chatelier.* Goldschmidt ** tested the accuracy of the 
formulze representing molecular solubility changes proposed by Van’t 
Hoff and Van Laar, and found the degree of dissociation was not the 
same as that which is calculated by means of either formula, neither 
was the heat of solution in agreement with the calculated values. 
The relation between solubility and heat of formation of electrolytes 
formed the subject of a discussion by Bodliénder.47 He found the 
solubility of different salts of the same metal to be greater the greater 
the tendency for the acid radicle to pass into the ‘ ionic state.’ With 
different salts of the same acid similar observations were made, namely, 
that the solubility is greater when there is a greater tendency for the 
metal to pass into the ‘ionic state.’ These facts were explained by 
reference to variations in the heats of formation of the salts. 
Evidence in favour of a theory of solubility based upon association 
was published by Brown,*® who made the interesting observations that 
the boiling-point of 50 per cent. alcohol is not raised but is lowered by 
the addition of potassium chloride, and carbamide, which is equally 
soluble in water as in alcohol; raises the boiling-point of 50 per cent. 
alcohol. 
1900 Rothmund ** pointed out that notwithstanding the results 
“—"" obtained by Gordon, Roth, Euler, and others, many scientists 
still assume that the addition of a salt has no effect on the solubility of a 
non-electrolyte. A study of the influence of salts on the solubility of 
phenylthiocarbamide furnished additional evidence in contradiction of 
such an assumption. 
The conclusion of Noyes and Whitney that dissolution is a diffusion 
phenomenon was supported by the work of Bruner and Tolloczko 7* on 
the rate of dissolution of benzoic acid and of gypsum. 
Stortenbecker 7° continued his studies of mixed hydrated crystals, 
dealing with cadmium and ferrous sulphate, and copper and manganese 
sulphate. 
The increased solubility of the carbonates of the alkaline earth metals 
when in the presence of carbon dioxide is well known; Bodldnder 7’ 
showed how this can be calculated at different pressures of carbon 
dioxide from a knowledge of the solubility of carbon dioxide in water, 
the conductivity of the solution, the dissociation of the water, and the 
solubility of the carbonate in pure water. 
In a publication dealing with ‘ The relation of ammonia to salts in 
aqueous solution,’ Konowalow *° criticised vehemently the dissociation 
theory of solutions, and insisted upon the formation of hydrates in 
solution. 
Further confirmation of Jahn’s equation for gaseous absorption 
was furnished by the research of Levi.1°’ It was found to express the 
relationship obtaining when nitrogen dissolves in solutions of 
Be: methylic alcohol containing an electrolyte (potassium iodide) or 
a non-electrolyte (carbamrde). 
* Vide Part I. R. 202 and 221, 
