KINETICS OF CERTAIN SILVER SALTS 275 



bulky and cumbrous apparatus, while it was especially de- 

 sirable to study dilute solutions, and to use apparatus which 

 was not subject to such disturbances as variations of tempera- 

 ture, osmose, and the jars unavoidable during mechanical 

 handling produce. Considerations which will be explained 

 later led us to attempt the acquisition of fresh material, es- 

 pecially with reference to highly dilute solutions. We found 

 that we could do this by studying certain silver salts, mainly 

 organic; and we were led to this choice firstly because silver 

 is the only monovalent metal which furnishes a satisfactory 

 electrode a matter of some moment for our subsequent 

 work; secondly, because its salts are readily obtained in the 

 needful state of purity; finally, because Volhard's beautiful 

 method of titration l enabled us to perform the necessary 

 analyses with great ease and extreme nicety. We also 

 availed ourselves of the opportunity for studying the effects 

 of temperature and concentration upon the velocity of the 

 ions of these salts, because one of us 2 has recently shown how 

 important a part is played by these factors in the kinetics of 

 solutions. 



[108] 2. APPARATUS FOR THE DETERMINATION OF THE 

 RATE OF TRANSFERENCE 



In this apparatus we wished to avoid the use of membra- 

 nous diaphragms, and to minimize the internal resistance, 

 necessarily large by reason of our very dilute solutions, so 

 as to keep the necessary duration of an experiment within 

 reasonable limits. After various failures we finally hit upon 

 a form whose simplicity is likely to recommend it in similar 

 cases. As shown in the accompanying drawing, it is seen to 

 resemble the Gay-Lussac burette, but with the addition of 

 a short side-tube of the same bore as the main tube. This side- 



1 Volhard, Annalen, 190, 1. 2 Nernst, Zeitschr. 2, 613. 



