460 REPORTS ON THE STATE OP SCIENCE. 



methylic alcohol and towards moist metliylic alcohol, observed by 



Klepl,* 9 also the observations of Goodwin 93 (vide Section V. A), 



' all point to solubility being dependent upon more than some 



purely mechanical process ; the latter author concluding it to be more of 



a chemical process at low temperature, and more mechanical at high 



temperature. 



In the next year Nicol 96 put forward views on the nature 



' of solution, which had much in common with those previously 



expressed by Dossios (1867). He suggested a possible relationship 



exists between molecular volume and solubility of solids, similar to that 



19S4 found between the molecular volume and the boiling-point of 



" liquids; instances of this were adduced in a later publication. 102 



From a very extensive examination of the behaviour of solutions of 



a large number of isomeric organic compounds Traube 1U4 was 



" able to conclude that the solubility of a substance and the 



cohesion of the solution are in some manner directly related. 



As a result of further research Nicol 124 showed the solubility 



isftfi °^ a sa ^ k° k e dependent on the relation between the cohesion 

 loob. Q £ ^ e g£ jj. anc j ^ e ^hggjon f solvent to the salt. Alexejefj 118 



found the state of aggregation had a decided influence on the solubility 

 of salicylic and of benzoic acids. 



The research of F. Braun 133 [vide Section V. B.) has also 

 ,oo 7 to be mentioned in this section; likewise the relationship, 



although somewhat obscure, observed by Kosman 135 between 

 the amount of salt that saturates 100 parts of water and the molecular 

 weight of the hydrated salt. 



A systematic study of the precipitation of salts from their aqueous 

 lftftft solutions by the addition of the corresponding acids led Engel 139 



to conclude this process to be in no wise due to a dehydrating 

 effect of the added precipitant; in arriving at this conclusion, however, 

 this author entirely neglects to consider any affinity existing between 

 salt and water. 



That salt solutions are very weak chemical compounds was 



inferred by Setschenoff, 1 * 2 while almost at the same time 



Nernst 144 regarded the process of dissolution as being perfectly 

 similar to that of vaporisation; the molecules in botli cases assuming 

 the gaseous state. The specific attraction between salt and solvent was 

 considered by this investigator to be non-existent ; the process of disso- 

 lution being independent of such influences. As the distribution of a 

 vapour takes place in the atmosphere of an indifferent gas as in a 

 vacuum, so the solubility was assumed to be unaffected by the presence 

 in solution of a second substance, provided always the two are without 

 chemical action one on the other. The work of Horsfmann referred to 

 (vide Section V. C (iii, 1889) showed the addition of a product of dis- 

 sociation caused a separation of the substance vaporised, an indifferent 

 gas not being capable of this action. On these lines the precipitation 

 of a dissociated substance in solution by the addition of a compound 

 giving an ' ion ' in common with one in solution was considered as 

 being caused by the increased osmotic partial pressure of that ' ion ' 

 being greater than the solubility tension of the solid substance, and 



