no Conductivity of Aqueous Solutions. Part IV. 



Table 29. Un-ionised fraction in relation to valence-product. 



It will be seen that the principle continues to hold, especially when the 

 comparison is made at the same equivalent concentration, even when the 

 ionization has become very small ; thus it is only 26 per cent for the uni- 

 bivalent salts at 306 and only 7 per cent for the bibivalent salt (magne- 

 sium sulphate) at 218. 



In correspondence with this principle, the rate of decrease of ionization 

 with rising temperature for the individual substances is greater for the 

 unibivalent than for the uni-univalent salts, and is still greater for the 

 bibivalent salt magnesium sulphate. Moreover, the rate of decrease of 

 ionization per degree increases rapidly with rising temperature, especially 

 above 100. The following values of ( 10 3 Ay/A^), which represent the 

 absolute decrease in percentage ionization produced by a rise in tempera- 

 ture of 10, illustrate these statements. 



Table 30. Temperature-coefficients of ionization ( io 3 A7/Aj). 



45. SUMMARY. 



In this article have been presented (in table 22, section 41) values for 

 the equivalent conductance of silver nitrate, potassium sulphate, and 

 barium nitrate at six different temperatures lying between 18 and 306 

 and at concentrations between 0.002 and 0.08 or 0.1 normal. Similar values 

 are given for magnesium sulphate up to still higher concentrations for 

 four different temperatures extending up to 218. From these by graphic 

 extrapolation have been derived equivalent conductance values for zero 

 concentration, which are proportional to the migration-velocities of the 

 constituent ions. The ratios of the conductance at the various concen- 

 trations to that at zero concentration, which ratios represent approximately 



