16 



Studies on Solution. 



mium chloride in water served as a color screen, and such a screen was 

 used whenever a was determined for wave-lengths greater than 1,200/zju. 

 This absorbs the light up to 700|//x (see fig. 24) and is transparent for 

 wave-lengths above this. Water itself is quite opaque above 1,300/xju 

 (see fig. 3) and hence this screen cut down the deflections to such an 

 extent that the values for a were liable to great inaccuracy. In most 

 cases, therefore, the long- wave limit of the absorption curves is at 

 about 1,200/i/u. 



TABLE 2. Nickel Sulphate in Water, 

 Temperature 18.6. < = 10mm. c=0.4. 



Kahlbaum materials were used, and when possible the salts were 

 purified by recrystallization. In preparing the solutions a uniform 

 method was adopted. A solution saturated at room temperature was 

 prepared, and the concentration was determined by a standard method. 

 The solutions of lower concentration were then prepared by diluting 

 this mother solution. 



