848 REPORTS ON THE STATE OF SCIENCE.—1912. VII. 
From a study of the influence of various electrolytes on the distri- 
bution of ammonia between water and chloroform, Dawson and 
McCrae *! were led to conclude that the solvent power of water is 
changed to a varying extent by the different ‘ions ’ present. Cameron *® 
regarded the peculiar effect on the solubility of gypsum produced by 
common salt as being inexplicable by the current hypotheses regarding 
solutions. 
Enklaar ° endeavoured to explain the anomalous solubility of 
sodium chloride when in the presence of hydrogen chloride on the pos- 
sibility of a change of volume of the water being conditioned by the 
‘ions ’ of the hydrogen chloride. 
The conclusion of fitard* that the temperature-solubility graphs 
for salts are straight lines if the solubility is defined as the weight of 
salt in 1,000 grms. of saturated solution was shown to be erroneous by 
Cohen and Biichner.+°° 
Nernst ** contributed a theoretical and mathematical discussion of 
solubility in which he made use of Wilsmore’s experimental results. 
The manner of representing mathematically the velocity of dissolu- 
tion formed the subject of a controversy between Drucker and Bruner 
and Tolloczko. Drucker ** considered that the formula proposed by 
Noyes and Whitney was insufficient, inasmuch as it does not take into 
account the volume of the solute, and he deduced a more general formula. 
Bruner and Tolloczko 1°? endeavoured to show that Drucker’s con- 
clusions were vitiated by experimental error, and he, in reply,}°4 refused 
to regard the constants of the Noyes-Whitney formula as diffusion con- 
stants. 
The process of dissolution was defined by Wyrouboff 1°! as the dis- 
aggregation, or the setting at liberty of the molecules of a solid sub- 
stance. Seeing that this change must be accompanied by absorption of 
heat, those cases of dissolution where the reverse takes place were con- 
cluded to be accompanied by secondary phenomena, such as polymor- 
phous changes, combination with solvent, &c. 
1902 A theoretical discussion of solubility graphs was published 
* by Lumsden.* The factors which condition the solubility of a 
substance were considered to be (i) affinity between solvent and solute; 
(1) thermal energy of the solid; (iii) pressure of dissolved particles— 
osmotic pressure—all of which vary with change of temperature and 
pressure. Normal solubility graphs were stated to be those which are 
convex to the temperature axis, although graphs showing a diminution 
of solubility with rise of temperature and then an increase, were not 
considered to be anomalous: such graphs being only peculiar in having 
the descending portion come within the observed range of temperature. 
The reciprocal nature of solubility influence was discussed by Roth- 
mund and Wilsmore.1*® They deduced that if the solubility of a sub- 
stance A is lowered by the addition thereto of substance B, then that of 
B must be lowered by the addition of 4. If L, and L, represent the 
solubilities of the pure substances and 1, and 1, the solubilities in a 
saturated solution of both, then 
1, log (7) = ly log (7) 
1 2 
* Vide Ann. Phys. Chem. [1898] (iii), 65, 344. 
