ON SOLUBILITY. 795 
APPENDIX II. 
A Report on Solubility. Part I. 
By J. Varcas Eyre, M.A., PhD. 
[Ordered by the General Committee to be printed in extenso.] 
PAGE PAGE 
I. Introduction . eecob) || V. Solubility in relation to 
Il. Methods of Deter mination—' | B.—Pressure . 818 
A.—Solids . . «. . 796) C.—Influence of other Sub- 
B.—Liquids Ang Meee 20018) stances— 
C.—Gases .. - 800 (i) Non-electrolytes and 
my yee of Nature of Sole ent— non-electrolytes . 820 
A.—Physical . . 802 (ii) Non-electrolytes and 
B.—Chemical . . . 804 | electrolytes . . 822 
IV. Influence of Nature of Solute— (iii) Electrolytes and elec- 
A.—Physical . . =. 807 trolytes . 830 
B.—Chemical . . . 809 VI. Mutual Solubility and Dis- 
C.—Molecular weight . 810 tribution Coefficients . . 841 
V. Solubility in relation to VII. Theoretical Considerations . 845 
A.—(i) Temperature . 813 | VIII. Chronological tie isa 855 
(ii) Heat of Dissolution 817 IX. Authors’ Index - 865 
I. IntTRoDucTION. 
Iy this Report a brief account is given of the various researches on 
solubility that have been published, and the main conclusions arrived 
at, in so far as they have a bearing on the general subject. The matter 
is arranged chronologically and as far as possible according to subject. 
A systematic study of the literature was commenced in 1908, and 
Part I. of this Report, relating to the period 1790 to 1895, was presented 
at the Sheffield Meeting in 1910; the work published up to and during 
1911 is summarised in this second part. All references are made to 
the original papers, which have been consulted in nearly every case 
quoted. The scheme of classification followed is that adopted in 
Part I. 
It is quite remarkable how much attention has been devoted to the 
study of solutions during the past fifteen years, and how views which 
differ fundamentally have been developed regarding the phenomena. 
Taken as a whole, the trend of recent research is to show that the 
dissolution of a substance involves far greater changes than the mere 
dissemination either of its particles (molecules) or of their constituent 
parts (ions) among the inert particles of solvent; moreover, in the 
light of recent observations, it is not possible to regard solvents, 
especially in the case of water, as inert media acting merely as 
diluents. The recognition of this circumstance, together with a more 
careful study of the facts said to justify the application of the 
ionic dissociation hypothesis to solubility problems, have necessitated 
a fundamental change of view. It is probable that, at no distant date, 
the use of the term ‘‘ ion ’’ in connection with solution problems may 
