n2 



Mr, W. E. Bousfield and Dr. T. M. Lowry. [June 19, 



of solutions in sulphur dioxide of hydrogen chloride, quinoline, and a 

 number of organic iodides. The first of these solutions is of special 

 interest, since hydrogen chloride is known to be of itself a non- 

 electrolyte, and to possess no power of self-ionisation ; the conductivity 

 of its solution in sulphur dioxide, unlike that of the salt-solutions 

 examined by Hagenbach, appears to decrease regularly to a zero value 

 at the critical temperature, which is therefore identical with the upper 

 conductivity zero of the solution. 



We are now in a position to review the influence of temperature on 

 the conductivity of a " composite electrolyte " over the whole range of 

 temperature within which it remains a conductor. Its general charac- 

 ter may be represented by means of a curve (fig. 3), in which tempera- 



tures are represented as abscissae on a horizontal axis and conductivi- 

 ties as ordinates. At some intermediate temperature T 3 , depending 

 on the nature of the solvent and solute as well as on the concentration 

 of the solution, the conductivity reaches a maximum and the tem- 

 perature coefficient is momentarily zero. As the temperature falls the 

 conductivity decreases, the increasing viscosity more than counter- 

 balancing the effects of increasing ionisation. Over a considerable 

 range, BC, the curve follows an approximately linear law, the line 

 becoming concave to the axis of temperature near C, and convex near 

 B. On this part of the curve the conductivity of the majority of 

 aqueous solutions must^be represented, the acids giving values on the 

 concave and the salts on the convex part of the curve. This portion 

 of the curve would, if produced, cut the horizontal axis at T 2 , the 



