832 REPORTS ON THE STATE OF SCIENCE.—1912, V.c. iii. 
The researches of Riidorff on the condition of equilibrium between 
a solution saturated with two salts and the solid solutes was extended 
by Massol and Maldés.** Experimenting with copper sulphate and 
sodium sulphate these authors found the composition of the saturated 
solution is fixed when both salts are present in excess and the tempera- 
ture is 15° C. At temperatures higher than this—namely, 30° or 50°— 
they found that the composition of the solution varied with the 
relative amounts of the two solids present. It must be observed, 
however, that their results may have been complicated by the appearance 
at these temperatures of different hydrates, a possibility which they have 
not taken into consideration. 
Work was published by Drucker?°* which was in direct opposition 
to the conception of a ‘ solubility product.’* He found that whereas 
potassium sulphate decreases the solubility of silver sulphate in water, 
sulphuric acid increases it. The solubility of mercurous sulphate is 
also first increased and then lowered by the gradual addition of 
sulphurie acid. 
Dawson and McCrae *' studied the influence of various electrolytes 
upon the distribution of ammonia between water and chloroform. 
Carbonates and sulphates were found to have most influence, iodides, 
bromides, chlorates, and nitrates exerting less influence; ammonium 
and lithium salts were less active than potassium and sodium. 
Cameron ** found the solubility of gypsum to be greatly increased 
by the addition of sodium chloride; a fact which explains how it is 
that such a relatively large proportion of gypsum is present in sea- 
water. Magnesium chloride was found *® to occasion a maximum 
solubility for gypsum, calcium chloride lowers its solubility, whilst 
sodium sulphate depresses the solubility to a minimum and then 
increases it on further addition of the salt. 
Enklaar **° studied the diminution of solubility of sodium chloride 
when in presence of hydrogen chloride. Making the assumption that 
both these electrolytes are equally dissociated, the solubility is stated to 
be correctly expressed by the following equation 
m= -2/o+ Vm +o], 
in which x=concentration of HCl and m, the solubility of NaCl in 
pure water. The solubility actually observed was always less than 
the calculated, and the sum (z+ m) is nearly a constant and equal to 
m,. Similar relationships were observed with barium chloride and 
hydrogen chloride and with barium nitrate and nitric acid. It is of 
interest to observe that the solubility of sodium acetate was found to 
be almost unaffected by the presence of acetic acid. 
The influence of certain fluorides on the solubility of cadmium, 
mercury and lead fluorides was investigated by Jaeger.'°° 
1902 Following a preliminary note+ Findlay 4+ published the 
“ application of Ramsay and Young’s t expression R= R! + C (t' — 1) 
correlating the vapour pressure of two substances, for the representa- 
tion of the solubility relationship between two bodies. In this applica- 
* Vide Nernst, Part I. R. 144. 
+ Zeit phys. Chem., 41, 28. This Part, R. 127. 
t Phil. Mag. [1886] (5), 21, 33. 
