200 Conductivity of Aqueous Solutions. Part VII. 



(1) February 30, 1905. Same as stock solution No. 2 of Noyes and Kato (see 



Part VI). 



(2) April 11. From Baker and Adamson's aqua ammonia used by Noyes and 



Kato. 



(3) June 8. From a new supply of Baker and Adamson's aqua ammonia. 



(4) June 10, and (5) June 16. From liquid ammonia. 



(6) June 24. From same supply as No. 3. 



(7) July 19, (8) October 16, and (9) November 2. From liquid ammonia. 



(10) February 2, 1906, and (11) February 19. From liquid ammonia distilled 

 from ammonium nitrate. 



(12) March 3. From a new supply of Baker and Adamson's aqua ammonia. 



(13) May 22. From same supply as No. 11. 



The acetic acid was made from a preparation of Kahlbaum, marked 

 "99 - 100 per cent." This was twice fractionated by freezing, and once 

 distilled, the yield being 200 grams out of 625. The distillate was received 

 in three fractions. Solutions Nos. 1 and 2 (July 14, 1905) were made from 

 the second and third fractions respectively. No. 3 (July 18) was from the 

 same acid as No. 2, redistilled once. Nos. 4 (October 9, 1905) and 5 

 (May 6, 1906) were from the same acid as No. 1, redistilled twice. No. 

 6 (May 12, 1906) was made from a new supply of the Kahlbaum acid, 

 redistilled three times, the portion used distilling at 117.7 to 118.0. The 

 concentration was determined by titrating the standard barium hydroxide 

 with the acid, using phenolphthalein as indicator and excluding carbon 

 dioxide. 



The ammonium acetate solutions were made by mixing weighed quan- 

 tities of the ammonium hydroxide and acetic acid solutions in such propor- 

 tion as to form a neutral solution. Large enough quantities were taken 

 to make the error of weighing negligible. Solution No. 1 was made from 

 ammonia No. 7 and acid No. 3 ; No. 2, from ammonia No. 8 and acid No. 4. 

 The same solutions were used in adding an excess of acid or base as were 

 used in making the neutral salt solution, except in the experiments fol- 

 lowing Expt. No. 2.18 ; in these, acid solutions Nos. 5 and 6, and ammonia 

 solution No. 13 were used. 



The ammonium chloride was made by first subliming Baker and Adam- 

 son "C. P." salt, "free from traces of hydrocarbons," then recrystallizing 

 this salt three times. Part of the salt was dissolved in water of specific 

 conductance 0.8 X 10~ 6 , and the concentration of this solution (No. 1) 

 found by precipitation with silver nitrate to be 100.8 milli-equivalents per 

 kilogram.* For comparison, solution No. 2 was made by mixing the 

 proper quantities of standard hydrochloric acid and ammonia No. 9. 



The sodium acetate was made by recrystallizing J. T. Baker's "C. P." 

 analyzed preparation, the analysis being given as "no iron or other metals, 



*Derived from the following data : 



Grams of solution 109.29 113.07 121.24 



Grams AgCl 1.5800 1.6337 1.7518 



Milli-equivalents per kilogram 100.83 100.77 100.77 



