THE COLLOID-CHEMISTRY OF SOAPS 



L45 



The potassium soaps, it is obvious, begin to foam at lower temper- 

 atures than the corresponding sodium soaps (see Fig. 79) but 

 th -y also lose this quality sooner with increase in temperature. 

 When the tube marked 11 of the potassium series (Fig. 85) is 

 compared with the corresponding tube of the sodium series 



FIGURE 82. 



(Fig. 79) the more li<|m<l character of the potassium soap/water 

 system e\ idem <> itself by the better foam production. Fig. 

 86 shows IIM\N tin- foams of the potassium soaps look at tl, 

 of two hours. It is again obvious that they die down earlier 

 in the series of the potassium soaps than in the corresponding 



so. In JIH soaps, Or, put another way. they last longest in the higher 



,,f the potassium soaps and at the lower temperatures. 



