THE COLLOID-CHEMISTRY OF SOAPS 95 



Table XXVII and Fig. 58. There is at first a progressive increase 

 in viscosity until a beautiful gel is formed. Further addition 

 of the alkali then brings about a 

 separation of the soap from the 

 water as already described for 

 potassium hydroxid. 



Table XXVIII and Fig. 59 

 show that none of these things 

 happen when equinormal ammo- 

 nium hydroxid is added to the 

 potassium oleate. In fact, even 

 if the concentrations of the 

 ammonium hydroxid are carried 

 beyond those in the table no 

 gelation and no separation of 

 the soap occurs. The reasons 

 for this are discussed later. 



The fact of interest in these 

 parallel series of experiments is 

 that the sodium hydroxid leads 

 to increase in viscosity and the 

 setting of the soap into a solid 

 jelly at a somewhat lower con- 

 centration than is the case for 

 potassium hydroxid; and this 

 same shifting of effect toward 

 t he left is true of the separation 

 of the soap from the aqueous 

 dispersion medium in the higher 

 concentrations of the alkali. 

 To the meaning of these things 

 we shall return later. 



3. We next compared th< 

 effects of a group of salts having 

 a common base and different acid 

 radicals. To simplify matters 

 a series of potassium salts was 

 chosen. 



The effect of the halogens is shown in T .1 1. \ \ 1 \ \ \ \ 

 XXXI and XXXII. Photographs of the chloric! and bromid 



