28 



the scattered indications in the literature it is evident that many 

 colloidal substances of great industrial importance must exhibit 

 similar behaviour and be classed together Avith soaps as colloidal 

 electrolytes. 



This conception leads then to the following complete circle of 

 continuous transitions between types of solutions and sols through 

 each of the -n'eU-recognised intermediate types. For convenience, 

 the circle is given as a table. The + signs indicate the relative extent 

 to which osmotic pressure and conductivity are exhibited by the 

 various standard types. The table is intended to represent the 

 natural sequence of transition in which consecutive pairs are much 

 closer than non- consecutive pairs. Thus there is evidently a gradual 

 transition from neutral colloid through semi-colloid (not through 

 charged colloid or coUoidal electrolyte) to ordinary crystalloid, that 

 is, non-electrolyte. Some of these transitions may be reaUsed in 

 the case of soap solutions by merely altering the concentration or 

 temperature or by passing from one member of the homologous series 

 to another. 



Table I. 

 Circle of Continuous Transition between Types of Solutions and Sols. 



Group. 



Examples. 



Osmotic 

 Activity. 



Conductivity. 



Crj'stalloid, non-eleetrolj'te 

 Semi colloid 

 Neutral colloid- 

 Cliarged colloid 

 CoUoidal electrolyte 

 Crystalloidal electrolyte - 

 Electrolyte 



Crystalloidal non-electro- 

 lyte. 



Sucrose 



Dextrines 



Pauli's egg albumin 



Gold sol 



Soap, dyestuiis 



KCl - 



HgCla 



Sucrose 



+ + + 



+ 







+ 



+ + 

 + + + 

 + + + 

 + + + 





 

 



+ 

 + + + 



+ + -f 

 + 







The conception here presented of the constitution of soaps and 

 their solutions, gels, curds, and sediments is only a preUminary sketch 

 but its main outlines would appear to be authenticated by experiment. 



Selected Refeeences. 



Free use has been made in the text of the various investigations carried 

 out in this laboratory, a number of which have not yet appeared, and a few of 

 which are not yet completed. 



I. — Conductivity. 



1. Kahxenberg and Schheineii. (Zeitschr. physikal. Chem. 1898, 27, 552.) 



Conductivity of dilute solutions of sodiiun oleate, potassium stearate 

 and potassium palmitat«. Freezing points of N/8 and N/16 sodium oleate. 

 Boiling point experiments showing tliat the methotl was unreliable. 



