Summary. 



337 



conductance steadily decreases with rising temperature, so that the curve 

 is always concave toward the temperature axis. With the tri-ionic salts, 

 on the other hand, the rate of increase steadily increases, owing to the 

 great increase in the equivalent conductance of the bivalent ion ; the 

 curve is therefore always convex toward the temperature axis. 



It is of interest to note that the fluidity, or the reciprocal of the 

 viscosity, of water shows nearly the same increase as the conductance 

 of the di-ionic salts, at any rate up to 156, which is about the limit to 

 which previous determinations of the viscosity have extended. Thus, 

 using for the viscosity (rj) the data of Thorpe and Rodger and of de 

 Haas* and taking the mean values of A for the five uni-univalent salts 

 included in this research, the product v;A has the values 1.19 at 18, 1.04 at 

 100, and 1.01 at 156. When it is considered that the conductance values 

 increase five- fold, this variation in the ratio will be seen to be of secondary 

 significance. 



With respect to the variation of the equivalent conductance (A) with 

 the concentration (C), it has been found that between the concentrations 

 0.1 and 0.002 or 0.0005 normal the results at all temperatures with all the 

 salts, both di-ionic and tri-ionic, and also with hydrochloric acid, nitric 

 acid, and sodium hydroxide, are expressed by the function C(A A) = 

 K(CA)" provided that to the exponent n a value (varying with the differ- 

 ent substances) between 1.40 and 1.55 is assigned. This is clearly shown 

 by the summary of the 11 values given in table 140. These were derived 



Table 140. Values of exponent n in the function C(A A) = iv(CA)". 



*See Landolt-Bornstein-Meyerhoffer. Physikalisch-chemische Tabellen, pp. 76-77. 

 From the data there given the viscositv in dynes per sq. cm. is found by interpola- 

 tion to be 0.01052 at 18, 0.00283 at ]00, and 0.001785 at 156. The mean values of 

 A for the salts referred to are 113 at 18, 369 at 100, and 566 at 156; the salts 

 investigated were potassium, sodium, and ammonium chlorides, sodium acetate, and 

 silver nitrate. Reference may also be made to the table given in Part II, page 53, in 

 which a comparison is made between the change in fluidity and that in the equivalent 

 conductance of potassium chloride for six temperature-intervals between and 156. 



