IL.c. ON SOLUBILITY. 801 
of the gas burette by having an enlargement blown in the central portion 
of the tube. 
1903 When determining the solubility, under pressure, of oxygen, 
“~** hydrogen, nitrogen, and carbon monoxide in water, Casuto 181 
confined the gas in a graduated glass tube, which was connected with 
a cylindrical bulb containing a known quantity of water kept agitated 
by a soft iron stirrer controlled by a solenoid. 
McLauchlan**> determined the vapour pressure of hydrogen 
sulphide in solutions of salts by means of a dynamical method, and 
also the solubility by an analytical method; he obtained accordant 
results, thereby establishing the validity of Henry’s law in these cases. 
1904 Knopp '°S made use of a slightly modified form of the 
* apparatus used by Roth, Timofejeff, and others, but took the 
precaution of placing the whole apparatus in a suitably large reservoir 
of water, so as to maintain an equal temperature in all parts of the 
apparatus. 
A very exact method of estimating the absorption of purified carbon 
dioxide by aqueous solutions of various hydrates and carbonates was 
devised by Raikov ?1*4; this method, as well as those already referred 
1905, © was made use of by Christoff?°** when studying the 
* phenomena of absorption of the gas by solutions of other salts 
in water. 
1906 Hiifner ?7°* used a globular absorption vessel provided with 
* an inlet and outlet, the whole constructed of glass. This vessel 
contained the aqueous solution under investigation, which was boiled 
to free it from occluded air before admitting the gas. For the exact 
details of the various operations the original description * should be 
consulted. 
Some of the more recent work on gaseous absorption has been 
earried out under conditions which admit of remarkable precision being 
attained. The apparatus devised for the purpose, although based on 
some earlier and simple form, has necessarily become complex and 
difficult of manipulation. Of these, more particularly, mention must 
be made of the method and apparatus used by Usher *°% in 
aoe measuring the solubility of carbon dioxide in aqueous solutions 
of non-electrolytes, and also the apparatus described by Drucker and 
Moles.**? This last-mentioned apparatus was designed for measuring 
the solubility of gases in small quantities of liquids; it formed the 
subject of a further publication by Moles.**7 
An indirect method of determining the solubility of a gas in a liquid 
was developed by Jones.**® If V ccms. of air are bubbled slowly 
through v cems. of a solution containing a grms. of a gaseous solute, 
and if c grms. of gas are extracted by the air, then if S represents the 
solubility coefficient of the gas in the liquid, the following relationship 
igs true :— 
gle 
a 
Vv log, ate 
* Archiv f. Anatomie u. Physiologie, Physiolog. Abteilg. 1901, p. 191. 
1912. 3Fr 
