280 Mr. W. K. Bousfield and Dr. T. M. Lowry. [June 24, 



magnitude, whereas the "saline" ionisation does not. Taken in 

 conjunction with the electric conductivity, the cryoscopic method 

 should yield results of utility with soluble electrolytes whose ionisation 

 is considerable. As a means of determining the extent to which acidic 

 or basic ionisation, as distinguished from saline ionisation, has taken 

 place, measurements of electromotive force with hydrogen electrodes 

 may, in some instances, be applied with success. Experiments in this 

 direction are at present in progress. 



"The Electrical Conductivity and other Properties of Sodium 

 Hydroxide in Aqueous Solution, as elucidating the Mechanism 

 of Conduction." By WILLIAM EGBERT BOUSFIELD, M.A., 

 K.C., M.P., and THOMAS MARTIN LOWRY, D.Sc., Lecturer in 

 Physical Chemistry and Crystallography at the Central 

 Technical College. Communicated by Professor H. E. 

 ARMSTRONG, F.E.S. Eeceived June 24, Eead November 17, 



1904. 



(Abstract.) 



The original object of the research was to investigate the decay, as 

 the temperature rises, in the " ionising " properties of water ; which 

 is manifest, especially in the case of the alkalies, in the inflected 

 character of the curves expressing the relation between temperature 

 .and conductivity in aqueous solutions.* It was found, however, 

 that the available data for the physical properties generally of the 

 alkalies were very few ; the inquiry was, therefore, extended so as 

 to include the measurement of the density and conductivity of 

 solutions of sodium hydroxide at 18 C., as well as of the 

 temperature co-efficients of conductivity and density. The great 

 viscosity of the more concentrated solutions being very noticeable, 

 measurements of viscosity were also made, in order to correlate this 

 property with the low conductivity of these solutions. The principal 

 results of the investigation are as follows : 



(1) In the most dilute solutions, in which " ionisation " is nearly 

 complete, the curves expressing the relation between molecular 

 conductivity and temperature are not inflected between 5 and 

 100 C. They resemble the curves representing the changes in 

 viscosity with temperature in dilute aqueous solutions. Concen- 

 trated solutions also give curves that are not inflected. In these 

 solutions a very rapid increase of conductivity takes place as the 

 temperature is raised : the conductivity of a 50-per-cent. solution 



* Compare ' Roy. Soc. Proc.,' 1902, vol. 71, pp. 4254. 



