1 54 Conductivity of Aqueous Solutions. Part VI. 



were extended to 218, as the data at this temperature were needed in 

 interpreting the results of Noyes and Cooper ; and also to the higher con- 

 centration of 0.05 normal on account of the interest attaching to the 

 results themselves. 



After describing the apparatus and method used in all the experiments 

 and the preparation of the solutions, we will first present the results ob- 

 tained with the three substances last referred to, and then in separate 

 sections will present and discuss the hydrolysis experiments with ammo- 

 nium acetate. 



61. APPARATUS AND METHOD OF PROCEDURE. 



The same bomb was employed as in the investigation of Noyes and 

 Cooper (section 47, Part V) in the form designated by them as cell in, 

 that is, with a cylindrical platinized platinum-iridium electrode. The same 

 heaters were also used. The measurements at 51, 75, and 125 with the 

 ammonium hydroxide solutions were made in the liquid xylene bath com- 

 monly used at 18. It was heated electrically by means of a nickel-steel 

 resistance coil immersed in the xylene. The same three thermometers 

 were used in the 18, 100, 156, and 218 baths as before. That used at 

 156 and 218 was also employed in the few measurements at 125. The 

 100 point of the French thermometer (No. 65650) used in the bromben- 

 zene and naphthalene vapor-baths was frequently tested by heating in steam 

 in the usual Regnault apparatus. The Beckmann thermometer used in 

 the 100 bath was similarly tested. As in all the preceding researches, the 

 temperatures above 100 were reduced to the hydrogen-gas scale by means 

 of Crafts's table of corrections after modifying them in accordance with 

 the lower value for the boiling point of pure naphthalene found by 

 Jaquerod and Wassmer. A fourth thermometer was employed in deter- 

 mining the temperature of the liquid xylene bath when used at 51 and 75. 

 This thermometer was standardized by comparison with a thermometer 

 certified by the deutsche physikalisch-technische Reichsanstalt. A new 

 conductivity measuring apparatus of the roller type described by Kohl- 

 rausch and Holborn* was employed. It was calibrated as described in the 

 preceding parts. The maximum correction on the bridge-ratio at any 

 point was 0.06 per cent, that on the resistance coils 0.02 per cent, but 

 these corrections were always applied. The induction-coil was a small 

 one of the ordinary form. The procedure followed in the experi- 

 ments was nearly the same as in the preceding investigation. In fill- 

 ing the bomb with the solutions especial care was taken to avoid con- 

 tamination from the carbon dioxide of the air. Some of the solution 

 was forced by purified compressed air out of the bottle containing it 



*Leitverm6gen der Elektrolyte, 1898, p. 42, fig. 37. 



