OF AQUEOUS SOLUTIONS. BARNES. 133 



platinum wires to the ebonite covers. These electrodes were 

 platinized in the solution proposed by Summer and Kurlbaum. 

 The reduction factor by which the conductivities obtained in 

 this cell are reduced to the standard employed by Kohlrausch, 

 was obtained by comparing the value of the conductivities of 

 two solutions of pure potassium chloride, twice recrystallized, 

 of different concentrations, with values given by 2 Kohlrausch 

 for the same concentrations of the same salt. The ratio of 

 Kohlrausch's value to the observed value gives the reduction 

 factor. It was always determined before and after a series of 

 observations, and was found to be the same in value at both 

 times. 



Solutions of different concentrations of each acid were pre- 

 pared and carefully analysed. Fifty cubic centimetres of one 

 of these solutions was placed in the electrolytic cell at a time, 

 and two successive dilutions prepared in the cell by the addition 

 of known volumes of water at 18C. Then the other prepared 

 solutions were introduced in order, and the same process of 

 dilution repeated till a sufficient number of conductivity values 

 had been obtained. In the case of mixtures, equal volumes 

 (fifty cubic centimetres) of the constituent solutions were mixed 

 at 18 C., and the mixture was then placed in the cell. 



For a more detailed description of some of the above instru- 

 ments and methods, see my former paper on conductivity. 



Results of the Conductivity Observation* on Simple Solutions. 



It is necessary for the determination of the regional con- 

 ductivities (k) and the regional concentrations (C) in the 

 mixture (see my former paper), 8 to draw curves showing the 

 relation of conductivity to the concentration for each acid. In 

 the case of one of the electrolytes, (hydrochloric acid was 

 selected), the values of the conductivity must be multiplied by 

 a constant before plotting, this constant being the ratio of the 

 specific molecular conductivities at infinite dilution for the two 



. Ann., 66, 315, 1897. 

 "Kohl. u. Holb., loc. cit., p. 159. tab. 2. 

 8 Trans. N. S. Inst. Sci., 10, 113, 1899-1900. 



