ON SOLUBILITY. 447 



Pressure was regarded by Alexejeff 11S as having no special 

 influence on the solubility of a liquid in a liquid. 

 From a consideration of the influence of pressure in the light of the 

 theory of mechanical heat, Braun 133 supported Sorby's con- 

 clusions by adducing mathematical evidence that substances dis- 

 solving in their nearly saturated solution with development of heat and 

 diminution of volume have their solubilities increased by pressure ; 

 conversely, substances which dissolve either with absorption of heat 

 or with increased volume must be partially precipitated by pressure. 

 Later on in the same year he published 134 experimental verification of 

 his conclusions. 



1889 Woukoloff 147 published an adverse criticism of the conclu- 



sions of Khanikof and Louguinine,* and also of Wroblewski.f 

 that the absorption of carbon dioxide in water does not take place in 

 accordance with Henry's law. It is pointed out that this law only 

 holds when no chemical action occurs ; determinations of solubility of 

 this gas in carbon disulphide at various temperatures showed an 

 approximation to Henry's law. 



The influence of pressure on the solubility of salts and other sub- 

 qqj stances was considered at some length by Van der Waals, 1 * 1 

 more especially, however, from the mathematical side. 



An investigation by Konowaloff 2BS showed the validity of 

 Henry's law for the dissolution of carbon dioxide in aniline. He 

 also found the dissolution of ammonia in water at about 100° C. only 

 approximated to this law. 



V. 0. — Influence of other Substances. 



(i) Non-electrolytes influenced by Non-electrolytes. 



IftftQ With oxygen, hydrogen, and carbon monoxide Lubarseh 148 



- found a minimum of absorption occurred in dilute aqueous 

 alcohol at about the same concentration of alcohol as Midler found with 

 carbon dioxide ; he suggested that other gases will behave similarly 

 in this respect. 



It follows, as a consequence of Nernst's hypothesis to explain the 

 influence of a dissociated substance in solution on the solubility of a 

 second dissolved substance (vide Section V. C (iii) ), that the presence 

 of a non-ionised substance in the liquid should not influence the 

 solubility of an ionised substance, provided such non-ionised substance 

 is not identical with an ion of that which is ionised. 

 lftcn Ouido Bodlander 176 subjected this to the test, and, so as to 



' be free from dissociation phenomena, he considered the case of 

 the solubility of sugar as influenced by alcohol. 



Using Schiebler's solubility values he found that in aqueous alcohol 



solutions less sugar is dissolved than in the corresponding quantity of 



water by itself. This difference increased with increased concentration 



W . , 



of alcohol. The expression y-= = const, was arrived at as giving the 



V & 



* Ann. Ch. Ph. (4), 11, 412. t W*ed- Ann., 8, 29. 



G g 2 



