280 Prof. H. E. Armstrong. Electrolytic [Mar. 25, 



molecular simplification, and that, in consequence, conductivity will 

 diminish with rise of temperature ; a mixture of alcohol and ether 

 would appear to furnish an example of this kind; according to 

 Pfeiffer's recent observations (" Wied. Ann.," 1886, 26, p. 226), such a 

 mixture behaves as a metallic conductor of very high resistance. 



The increase in conductivity of graphite and gas-retort carbon on 

 heating, and the effect of light on the conductivity of (? impure) 

 selenium and some other substances (Shelford Bidwell, " Phys. Soc. 

 Proc," 7, p. 129, 256), appear to me to be also explicable on the 

 assumption that in all these cases we are dealing with composite 

 electrolytes. 



If any further proof be needed of an intimate connexion between 

 molecular composition and electrolytic conduction, it is most con- 

 clusively afforded, I think, by the observations of W. Kohlrausch on 

 chloride, bromide and iodide of silver (" Wied. Ann.," 1882, 17, 

 p. 642), which are exhibited in the accompanying curves. In the fused 



state, these compounds are better conductors than the most highly- 

 conducting mixture of sulphuric acid and water, which of all liquids 



