Wiowai. ON SOLUBILITY, 829 
or h becomes constant; further, if p=the vapour pressure, then the 
following relationship was said to hold good: 
h 
= ts n 
gn Const. X p 
The addition of foreign substances diminishes p, and in consequence 
. becomes diminished and the total solubility a+h becomes decreased ; 
if h is constant a must increase, and the total solubility is thereby 
increased. 
In the paper above referred to, Rothmund adversely criticised the 
views expressed by Abegg,* and also Philip’s + method of estimating the 
degree of hydration of salts from their effect in diminishing the solubility 
of gases in water. 
Traube **° attributed solubility-influences to ‘‘ cohesion-pressure.’’ 
From a study of the effect produced by non-electrolytes on the solubi- 
lity of lithium carbonate, silver sulphate, and potassium bromate, he 
concluded that the cohesion pressure of the non-electrolyte deter- 
mined the solubility of the salts. +t 
The very interesting observation was made by Pauli and Samec **? 
that proteins in aqueous solution have the effect of diminishing the 
solubility of easily soluble salts, such as magnesium chloride and am- 
monium chloride, whilst they cause an increase in the solubility of 
sparingly soluble salts such as calcium carbonate and calcium sulphate. 
The influence of sodium carbonate upon the miscibility of pyridine and 
water was investigated by Limbosch.*** 
An examination of the solvent properties of sulphuric acid for 
1910 carbon dioxide, oxygen and nitrogen was carried out by Bohr *75 
* and the following interesting results were established. Whereas 
these gases are practically as soluble in 96 per cent. sulphuric acid 
at 21° C. as they are in water, yet in more dilute acid solutions their 
solubility is much decreased, a minimum being attained at a concentra- 
tion of 25/Nn, which corresponds with the proportion of acid to water 
which gives a maximum contraction when mixed together. 
Armstrong and Eyre **® continued their work § dealing with the 
subject of the precipitation of salts from aqueous solution by alcohols, || 
their inquiry being extended to include a study of the behaviour of salts 
and other substances when employed as precipitants. The results of 
chief interest were that of the three alcohols, methylic, ethylic and 
propylic alcohol, the first was found to be the least and the last the most 
active precipitant of salts. The precipitating effect was always larger at 
0° than at 25° C.—a temperature difference which was found to be 
greatest for the alcohol of highest molecular weight and least for the 
alcohol of lowest molecular weight. 
The behaviour of alcohols as precipitants for metallic chlorides dis- 
‘ 
* Zeitschr. f. Elektrochem. 1901, 7, 677. 
+ J. Chem. Soc. 1907, 91, 711. t Vide Section VII. . 
§ A paper communicated to the Roy. Soc. in June, 1909, although not published 
until the following year. || Vide this Section 1907. 
