414 PROCEEDINGS OF THE AMERICAN ACADEMY. 



cussed at the end of Section IV, in order to obtain the most probable 

 values of the equivalent conductivity at infinite dilution. The values 

 so obtained are 380.1 for hydrochloric acid, and 377.0 for nitric acid. 

 The values recently derived by Kohlrausch * are 383.4 and 379.8 respec- 

 tively, Avhich differ from ours by less than 1 per cent. Unless the 

 change with the concentration at very high dilutions follows a law radi- 

 cally different from that prevailing at moderate dilutions, it seems cer- 

 tain that these values are substantially correct. The much higher value 

 395,5 for hydrochloric acid derived by Noyes and Sammet from transfer- 

 ence experiments apparently arises from some considerable error the 

 nature of which still remains to be explained. 



VII. Summary. 



In this article have been described measurements of the electrical 

 conductivity at 18° of very dilute (0.0001 to 0.002 normal) hydrochlo- 

 ric and nitric acid solutions made by adding to a known weight of water 

 successive portions of 0.01 normal acid. To eliminate the effect of the 

 impurities of the water, two methods of computation of the equivalent 

 conductivity have been used. In both of these, the assumption is in- 

 volved that the total effect of the acid and impurities on the conductance 

 of each other is produced when a relatively small quantity of acid has 

 been added to the water. The experiments themselves furnish evidence 

 of the correctness of this assumption. In the first method, the increase 

 of the specific conductance over this initial value divided by the in- 

 crease of concentration is regarded as the equivalent conductivity at the 

 higher concentration. In the second method, such a quantity, con- 

 stant at every concentration, is added to the observed values of the 

 specific conductance as will cause the maximum in the equivalent con- 

 ductivity values calculated therefrom to occur at the lowest concentra- 

 tion at which the total influence of the acid and impurities on each 

 other has been produced. In spite of considerable variations in the ob- 

 served conductivities due to the use of different samples of water, the 

 corrected values of the equivalent conductivity derived from different 

 experiments and those computed by the two methods agree well with 

 each other. New determinations were also made at higher concentra- 

 tions with hydrochloric acid. The final values of the equivalent con- 

 ductivity (A) at various round concentrations (C) in equivalents per 

 liter are as follows: 



* Sitzungsbur. d. koiiigi. preuss. Akad., lUOl, lOol. 



