166 DE. B. D. STEELE, DE. D. McINTOSH AND DE. E. H. ARCHIBALD 



The effect of this increased complexity would be that the velocity of the ion would 

 be diminished without altering the ionic change, and also that the concentration 

 change at the cathode would be lessened, owing to the carriage of extra solvent 

 molecules to the cathode. Both of these effects would cause a diminution of the 

 cation transport number as the solution was diluted. 



It will be noticed that this explanation involves a change in the active mass of the 

 solvent, and, as a matter of fact, it was not possible to measure the transport number 

 except in solutions which were so concentrated, that the assumption of a constant 

 active mass for the solvent was no longer justified. 



We have not been able to calculate, even approximately, the velocity of the various 

 ions, as we had no means of determining the actual nature, concentration, or degree of 

 dissociation of the corresponding electrolytes. 



Summary. 



The foregoing pages contain an account of measurements of the vapour pressures, 

 densities, surface energies, and viscosities of the liquefied hydrides of chlorine, bromine, 

 iodine, sulphur, and phosphorus. 



The solvent action of these substances has also been investigated, and we have 

 shown that, with the exception of phosphuretted hydrogen, they are all able to act 

 as ionising solvents, and the conductivity, molecular weight, and transport number of 

 certain dissolved substances have been measured. 



The results of the measurements, although abnormal, are not inconsistent with the 

 ionic theory ; since we have shown that 



(1) If in a given solution the electrolyte is a compound containing n molecules ot 

 the dissolved substance, the concentration of this compound will be proportional to 

 the n th power of the concentration of the dissolved substance, and therefore the 

 expression for the molecular conductivity of the electrolyte becomes icV" instead of /cV. 

 We have also shown that /cV" = aK', and therefore the molecular conductivity of the 

 electrolyte increases with dilution in these solutions in the same manner as in aqueous 

 solutions. 



The variation of the molecular conductivity of the electrolyte with dilution is 

 probably complicated by the occurrence of compounds which contain a different 

 number of solvent molecules at different dilutions. 



(2) The want of agreement between conductivity and cryoscopic measurements is 

 a necessary consequence of the occurrence of polymers or compounds in solution, and 

 may be taken as evidence of the existence of such compounds. 



(3) The conduction of organic substances when dissolved in the halogen hydrides 

 is best explained by the occurrence of electrolytic compounds of the organic 

 substance with the solvent. Transport number measurements have shown that the 

 organic substance is carried to the cathode as a component of the complex cation. 



