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PREFACE. 



This study of the conductivity and dissociation of electrolytes, and of the tempera- 

 ture coefficients of conductivity, was begun eleven years ago in connection with the 

 solvate theory of solution, which had been proposed in this laboratory shortly before 

 that time. Certain relations of interest, and I hope of some importance, between 

 the temperature coefficients of conductivity and the magnitude of the hydration of 

 the dissolved salt were pointed out. 



The work, thus begun, was continued especially for the following reason: When 

 reference was made to the literature for the conductivity of any electrolyte at any 

 given temperature, and for the temperature coefficients of conductivity, we were 

 frequently unable to find what was desired; or, if found, the data were often so dis- 

 cordant that it was impossible to decide what were the true conductivities and 

 dissociations in question. 



Since the magnitude of the dissociation of any electrolyte is fundamental to its 

 scientific use in chemistry, it seemed desirable that such data should be made avail- 

 able over the range of temperature most frequently used in the laboratory. With 

 this idea in mind the work has now been continued here until it represents more than 

 twenty years' continuous labor for one man, about 40,000 conductivity measure- 

 ments having been made. Every one of the investigators has worked from one to 

 two years on the problem, and Doctors Springer, West, and Wightman have each 

 continued their investigations between two and three years. 



The result is, that the conductivities and dissociations of about 110 of the more 

 common salts have been worked out from zero to sixty-five degrees, and over a range 

 in dilution extending from about the most concentrated solution that could be used 

 to the dilution of complete dissociation. The temperature coefficients of conduc- 

 tivity have been calculated in both conductivity units and percentages. Moreover, 

 similar data have been obtained, for about 90 of the more common organic acids, 

 and their constants have been calculated by means of the Ostwald dilution law. 



It is hoped that this work, which has consumed much of the best energy of my 

 laboratory for several years past, may prove to be of some value to other investi- 

 gators in the field of general or physical chemistry. 



Harry C. Jones. 



