798 REPORTS ON THE STATE OF SCIENCE.—1912, IIa. 
ence at electrodes of the type Ag/AgX, N/,,MX, when AgxX is the silver 
salt and MX a soluble salt of the metal M with the same anion: for MX 
the following substances were taken: KBr, KCNS, KCl, 4 Ba (OH),, 
4 Na,CO,, 4 K,CrO,, and 4 Na,B,O,. From the results obtained the 
solubility of AgX was calculated in accordance with Nernst’s theorem.* 
The conductivity method has been used by Béttger *° in determining 
the solubility of sparingly soluble salts: he has published full details of 
the method and of the precautions necessary to be observed. 
1904 A full description was given by Cantoni?}* of an apparatus 
* for determining the solubility of salts in solvents other than 
water. 
When measuring solubility at any particular temperature the Earl of 
Berkeley 7° took the precaution to make observations at 1° above and 
at 1° below the required temperature, and to take the mean of those 
results. He also designed a special form of apparatus for determining 
the solubility of salts and the density of their saturated solutions at the 
boiling point. 
1905 When measuring the solubility of ammonium nitrate in 
"various aqueous alcoholic solutions Fleckenstein 24° dissolved 
known weights of salt in known weights of solvent, and observed the 
temperature at which the solute began to crystallise. 
1906 Veimarn ?§4 described an apparatus whereby the solubility of 
’ solids in liquids may be conveniently determined and for which 
he claimed superiority over other forms: it was based on the same 
principle as that devised by V. Meyer, but had several novel features. 
When determining the solubility of a solid at the eutectic point, 
Trautz and Anschiitz °° slowly cooled the solution saturated at 0°C and 
analysed the last liquid fraction. This fraction was frozen and then 
partly thawed and the melted portion analysed. In the case of a true 
eutectic the results of the two analyses should agree, 
The solubility of salt mixtures at temperatures above the boiling 
points of their saturated solutions was determined by Thiele and 
Calberla.*** The mixed salts were dissolved in water in one chamber 
of a specially constructed closed tube which was maintained at constant 
temperature by superheated steam; the solution, when saturated, was 
filtered into a second chamber of the same closed tube, was slowly 
cooled, restored to ordinary pressure, and then analysed. 
Hartley and Thomas ?** used a closed-tube method, similar to that 
previously adopted by Kuriloff?*, in determining the solubility of 
triphenylmethane in organic solvents. Weighed quantities of solvent 
and solute were enclosed in small tubes, and these were then heated 
and the temperature observed at which the last crystal was (a) just 
growing and (b) just dissolving. The mean of many such observations 
of temperature was taken as being the temperature of saturation. 
1907 The ultramicroscope has been brought into use by Biltz 28° 
‘in determining the solubility of sparingly soluble substances. With 
the aid of this instrument it was found possible to determine the degree 
of dilution at which two solutions no longer give a precipitate when 
mixed, and in this manner to determine the solubility of the precipitate 
* Vide Part I., R. 144, 
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