V.c. i. ON SOLUBILITY. 821 
tion of other non-electrolytes such, for example, as chloroform, nitro- 
benzene, and toluene instead of water also caused an increased solu- 
bility of p-nitrophenol in the medium benzene. Of these added sub- 
stances, alcohols, esters, and ketones were found to exhibit the greatest 
effect, nitroparaffins the least effect, and hydrocarbons, also chloroform, 
did not change the solubility of p-nitrobenzene from that found in pure 
benzene. 
The solubility of carbon monoxide in binary organic mixtures was 
investigated by Skirrow.*8 
Jahn’s * empirical law correlating solubility of gases and the con- 
centration of electrolytes present in the aqueous solvent was found by 
Levi?’ to hold also for methylic alcohol solutions of potassium iodide 
and carbamide. 
In a communication upon the subject of the influence exerted by 
foreign substances on the solubility of phenylthiocarbamide and of boric 
1903 acid in water, Bogdan ‘"® published results showing that the 
’ solubility of these solutes is increased by the presence of non- 
electrolytes such as carbamide, sucrose, acetone, ethylic, and propylic 
alcohol. 
The work recorded by Schiff (1897) was carried further by 
1905 Strémholm,?42 and similar results were obtained. It was found 
’ that small quantities of water greatly increase the solubility in 
ether of a large number of organic compounds. More especially was 
this found to be true with hydroxyl compounds,, carboxylic acids, and 
phenols, although other compounds were also found to dissolve more 
readily in ether containing small quantities of water than when that 
solvent was perfectly dry. 
Morse and Fraser + having shown good reason for comparing weight- 
normal rather than volume-normal solutions, Philip *°" recalculated 
from available data the solubility of gases in aqueous solutions of non-. 
electrolytes—for example, hydrogen in chloral hydrate solutions. He 
found that on this basis of comparison approximately constant solu- 
bility values are obtained for hydrogen dissolved in water, although 
the proportion of chloral hydrate present may vary considerably. 
1908 The work of Kofler*° dealing with the influence of other 
* substances on the solubility of radium emanation is of interest, 
although its significance cannot well be appreciated until more is known 
of the nature of the emanation. In water-alcohol mixtures the emana- 
tion is increasingly soluble as the proportion of alcohol is increased ; 
cane sugar, however, decreases its solubility in water. 
An unusually pronounced instance of change in the solvent power of 
a liquid when a second liquid is added thereto is to be found in the work 
of Galeotti and Giampalmo.**° These authors experimented with zein, 
a protein obtained from maize, and found it to be insoluble in all pure 
solvents although readily soluble in mixtures of alcohol and water. The 
maximum solubility was observed to be in 60 per cent. alcohol. They 
also studied the variations of solubility of this protein in mixtures of 
water, alcohol, and acetone, and also in mixtures of chloroform and 
alcohol. 
* Vide Part I., R. 240. 
+ Amer. Chem. .1. [1905], 34, 1; [1906], 36, 1 and 39. 
