NATURE OF SOLUTION. 603 
been heretofore determined, and the following pages give the results of my 
determination of the coefficients for solutions of chlorides. The solutions were 
made to contain quantities of salt proportional to the molecular weights of 
the anhydrous chlorides, so as to secure an equal number of molecules in equal 
volumes. By this method it was hoped that any influence due to the number 
of molecules would become apparent. 
The method at first adopted was to saturate 10 c.c. of the solution with 
chlorine, read the temperature of a thermometer placed in the test-tube con- 
taining the solution, blow off the atmosphere of chlorine, run in excess of 
iodide of potassium, and titrate with hyposulphate solution. This method 
did not give concordant results, owing to the difficulty of getting rid of the 
superposed atmosphere of chlorine. A slight modification of ScHONFELD’s 
method was then adopted. This chemist has determined the solubility of 
chlorine in water at temperatures between 10° C. and 40° C. He passed the 
chlorine through boiled water contained in a flask fitted with a stopper having 
four holes bored in it—one each for the entrance and exit tubes, one for a 
thermometer, and a fourth for a bent tube through which the chlorine water 
was forced out, when required, by stopping the exit of the gas. To estimate 
the amount of chlorine dissolved at any temperature, a given volume of liquid 
was drawn off, diluted to a known volume, of which an aliquot part was 
titrated by the iodometric method (Ann. Ch. Pharm., xevi. 8). The 
apparatus employed in the present research is sketched in Plate XX XVL., fig. 
vil. Chlorine evolved in A from a mixture of potassium bichromate, and strong 
hydrochloric acid is washed in B, and led through G into the solution con- 
tained in E, thence away by F, a rubber tube, which can be closed at will by a 
pinch-cock. E was surrounded by a freezing mixture, after the liquid had 
been saturated at the ordinary temperature, and determinations were made as 
the temperature rose from the lowest point attained, by closing the tube F and 
receiving the liquid forced out through D in a specific gravity flask (10 c.c.), 
which was quickly stoppered, washed, immersed in a solution of potassium 
iodide, and opened to allow the solution to escape. The iodine set free was 
titrated with standard solution of sodium thiosulphate. The stream of chlorine 
was easily regulated by means of a burner under the flask A, and formed a 
most efficient stirrer for the solution in E. The temperature was accurately 
marked by a thermometer T, graduated in tenths of a degree. 
The solubility in water was first examined. The flask E was partially filled 
with water, and the chlorine passed through for some time at ordinary tempera- 
ture. The bath was then filled with ice, and the end of the tube D, which 
dipped below the surface of the water in E, was loosely plugged with asbestos, 
to act as a filter for the chlorine hydrate. As soon as the thermometer was 
