1902.] 



Conductivity of Electrolytic Solutions. 



47 



Kt = K 18 {l + a (*-l8) + /?(*-18) 2 }. 



In the case of solutions of very great dilution, the coefficient /3, 

 which determines the curvature of the lines (fig. 1) is related to the 

 coefficient oc, which determines the slope of the tangent at 18° C, in 

 accordance with the equation 



P = 0-0163 (oc -0-0174), 



and the whole influence of temperature on conductivity is thus deter- 

 mined by a single arbitrary constant. A similar equation is also used 

 by Kohlrausch to express the influence of temperature on the separate 

 ionic mobilities. Negative values of /5 occur only in the case of the 

 hydrogen ion, 



oc = +0-0154, p = -0-000033, 



and the acids which contain that ion ; positive values of p range from 

 that of the hydroxyl ion, 



oc = +0-0179, p = +0-000008, 



which obeys a law which is almost linear to that of the lithium ion, 



oc = +0-0261, P = +0-000155, 



where the curvature of the lines in the conductivity temperature 

 diagram is very pronounced. In order to make a direct comparison 

 between conductivity and viscosity — a comparison which is hardly 

 possible when two entirely different types of formula are used for the 

 two phenomena — we have sought to express the viscosity of water by 

 means of the formula 



^18 = r ]t {I + a (t - 18) + P(t- IS)*}. 



In order to make the comparison as exact as possible, we have 

 deduced the constants oc and p from the values given by Thorpe and 

 Eodger for the viscosity of water at 5° '45, 13° -52, and 30° '72, the 

 temperature limits being thus almost identical with those of Deguisne's 

 experiments, and have thus obtained the values 



oc = +0-0251, p = +0-000115, 



for the two constants. We find that between 5° and 55° this expres- 

 sion represents the experimental data with even greater closeness than 

 the formula used by Thorpe and Eodger, but that above 55° it gives 

 values smaller than those determined experimentally. The closeness 

 of the agreement is shown by the following table : — 



