58 Scientific Proceedings of the Royal Dublin Society. 
solution being titrated, also part of the condensed froth, the rest: 
of the froth allowed to settle all night. 
Filtered Solution, Condensed froth at Froth titrated next Filtered solution titra- 
25 C.CS. same time. ay. ted next day. 
c.cs. CaCl,. c.cs. CaCl,. clesuCaGle. c.cs. CaCl,. 
5°6 6°2 5:4 5°5 
5:5 6°25 5°3 5°3 
5°45 6.3 5°3 . 0°35 
5°5 5°4 
Mean, 5°5 Mean, 6°25 Mean, 5:3 Mean, 5°38 
To avoid, as far as possible, oxidation, and yet still further to 
increase the difference between the solution and its froth, as 
regards the amount of soap in each, the following plan was 
followed out :— 
Three Winchester bottles were now used, and the froth frac- 
tionated twice, the amount of condensed froth not allowing of 
further fractionation. 
The filtered solution was also fractionated, the froth thrown 
away, and the filtered solution fractionated ten times. It is. 
represented diagrammatically as follows :— 
Soap Solution 
D 
! 2 3 4 
ee 
