aqueous solution of rubidium and caesium chlorides. 385 



One experiment may be quoted at length. 



In this experiment there was a period of four hours, during 

 which the increase in concentration proceeded at a practically 

 uniform rate. 



At 5.30 the concentration was -00303 Mol. NaCl. 



At 9.30 „ „ „ -0087 „ „ 



Thus in four hours the increase was 'OObOll or •001417 per 

 hour. 



Experiments made in the same way with the other salts 

 yielded the following numbers. The observations are plotted in 

 %2. 



Fig. 2. 



Deci-normal Caesium chloride.. 



„ Rubidium chloride 



„ Potassium chloride 



„ Sodium chloride .. 



„ Lithium chloride ... 



•0018 Mol. per hour 

 •001748 „ „ „ 

 •001707 „ „ „ 

 •001417 „ „ „ 

 •001165 „ „ „ 



Or taking the rate of diffusion of potassium chloride as unity, 

 and disregarding the last decimal place, we have 



CsCl 1-05(5), RbCl 1-02(3), KCl 1-000, NaCl 0830, LiCl 0-68(4). 



below that of the water bath and some few minutes must have elapsed before 

 18° was reached. The effect of this delay is to slightly displace the curve to the 

 right without affecting its form except at the very beginning. My calculations are 

 based entirely on the inclination of the curve during a period beginning three 

 or four hours after the experiment was started. 



