96 



SOAPS AND PROTEINS 



series are shown in Figs. 60 and 61. It is obvious from the tables 

 and the figures that these neutral salts behave in the same general 

 fashion as the previously described hydroxids. With progressive 

 increase in concentration there is observed in all the series a pro- 

 gressive increase in viscosity of the soap until it sets into a stiff 

 jelly. With further addition of the salt the viscosity falls, a slight 

 turbidness develops and, later still, separation of the soap from 

 the dispersion medium sets in. This separation finally becomes 

 so great that the soap floats as a practically dry white mass upon 

 the underlying clear dispersion medium. Some difference seems 

 to exist in the power with which the four halogens lead to the 

 setting of the soap and its subsequent dehydration and separation. 

 The difference may, however, be one of experimental error only. 



FIGURE 58, 



It is exceedingly difficult, as everyone knows who has worked 

 quantitatively in these fields, to be sure of getting absolutely 

 equal rates and degrees of mixing and thus absolutely equal 

 effects when producing these various systems. 



Of other monobasic potassium salts the effects of the nitrate, 

 sulphocyanate and acetate have been studied. Potassium 

 nitrate acts very much like potassium chlorid as shown in Fig. 62 

 and Tables XXXIII and XXXIV. With increasing concentra- 

 tion of the added salt the soap first gels and then softens, though 

 the solubility limits of potassium nitrate, as seen in mixtures 9 

 arid 10 of Table XXXIV are such as to lead to the formation of 

 nitrate crystals in the tubes and not to an actual dehydration 

 and separation of the soap from the dispersion medium. 



The range from a liquid to a gel, through a secondary 

 zone of liquefaction succeeded by dehydration of the soap and 



