CONTRIBUTIONS FROM THE RESEARCH LABORATORY OF 



PHYSICAL CHEMISTRY OF THE MASSACHUSETTS 



INSTITUTE OF TECHNOLOGY. — No. 1. 



THE ELECTRICAL CONDUCTIVITY OF AQUEOUS 

 SOLUTIONS AT HIGH TEMPERATURES. 



L — DESCRIPTION OF THE APPARATUS. RESULTS WITH SODIUM 

 AND POTASSIUM CHLORIDE UP TO 306<^. 



By Arthur A. Noyes and William D. Coolidge 



Presented October 14, 1903. Received September 18, 1903. 



Contents. 



I. Plan of the Investigation 163 



II. Description of the Apparatus 165 



III. Details of the Construction of the Bomb 171 



IV. Procedure for the Conductivity Measurements 182 



V. Procedure for the Specific- Volume Measurements 186 



VI. Standardization of the Apparatus 187 



VIL Preparation of the Substances and Solutions 190 



VIII. Discussion of the Systematic Errors and their Correction 190 



IX. Experimental Data relating to the Specific- Volume Determinations 195 



X. Tiie Results of tlie Specific- Volume Determinations 197 



XI. E.xperimental Data relating to the Conductivity Determinations . . 198 



XII. Summary of the Conductivity Values 201 



XIIL Change of the Equivalent Conductivity with the Concentration . . 207 



XIV. Change of the Equivalent Conductivity with the Temperature . . . 213 



XV. Change of the Dissociation with the Concentration and Temperature 216 



XVL Summary 218 



I. Plan of the Investigation. 



Only a few isolated experiments have been previously published on 

 the electrical conductivity of salt solutions above 100°. Sack* investi- 

 gated the conductivity of three copper sulphate solutions up to 120°. 

 Maltby t found that upon heating up to 237° the conductivity of an 

 aqueous potassium chloride solution steadily diminished. Hagenbach t 



* Wied. Ann , 43, 212-224 (1891). 

 t Ztschr. phys. Chem., 18, 155 (1895). 

 I Drude's Ann., 5, 276-312 (1901). 



