810 REPORTS ON THE STATE OF SCIENCE.—1912. IV.c. 
Wolff **° made an extensive study of the solubility of some simple 
1906 and double cerous and ceric salts. Measurements were made by 
‘ Lowry *°° of the solubility of various di-halogen derivatives of 
camphor in alcohol alone and in presence of sodium ethoxide. In the 
latter case an increased solubility was always observed, but not in the 
case of B-bromcamphor, nor in cases where both a- and a’-hydrogen 
atoms were displaced. Increase of solubility was ascribed to the 
formation of small amounts of the stereoisomeric a/-compound. 
Foote and Menge ?** studied the relative solubilities of a number of 
sparingly soluble barium and calcium salts, and in the same year 
Walden *°* compared the solubilities of tetralkylammonium halides in 
various organic solvents. He came to the general conclusion that, for 
any one solvent, the solubility was greater the greater the complexity of 
the alkyl groups in the positive radicle. 
Béttger ?°" observed that whilst silver chloride is considerably more 
soluble at all temperatures than the bromide and the thiocyanate, yet 
the relative increase of solubility between 0° and 100° is much greater 
in the case of the two last-mentioned compounds than in the case of the 
chloride. 
The solubility of isomeric organic compounds in water, benzene, and 
1907 nitrobenzene was studied by Rogojawlenski*+® and others; 
"among the compounds examined were the o-, m-, and p-nitro- 
phenols, nitroanilines, and chlornitrobenzenes; the rule of Carnelley 
and Thomson,* that the most easily fusible isomeride is the most soluble, 
was confirmed. The ratio of the solubilities of the isomerides was found 
to vary with the solvent. Contrary to statements previously published, 
it was shown by Jones *°° that the solubilities of d- and l-isomerides 
are identical when dissolved in optically active as well as in inactive 
solvents. 
190 The solubility of monosodium, monopotassium, and mono- 
ammonium urates was compared by Gudzent,**® who made the 
curious observation that when these substances are shaken with water 
at any particular temperature the solubility passes through a maximum, 
and subsequently diminishes. This is not due to hydration of the salt 
nor to any other assignable cause. 
IV. C.—Molecular Weight. 
1897 In the course of his work on the sulphates and selenates of 
’ the alkali metals, potassium, rubidium, and cesium, Tutton *§ 
made determinations of the solubility of these salts, and found that in 
the two series, selenates and sulphates, the solubility increases as the 
atomic weight of the metal increases. A comparative study of the solu- 
bility at 0° of the hydrated sulphates of magnesium, zinc, and cadmium, 
carried out by Mylius and Funk,** showed that the molecular solubility 
of these salts increases with an increase in the atomic weight of the 
metal. With the object of finding the existence of some such relation- 
ship among the salts of the alkali and alkaline earth metals, these 
authors ?® measured the solubility of a number of chlorates, chromates, 
* Vide Part I., R. 136. 
