386 SCIENCE PROGRESS. 



curve shows maxima and minima, similar elements falling 

 on the corresponding points of each portion of the curve. 



The conductivities of an immense number of salts con- 

 taining one or more organic radicles have also been measured 

 and the velocities of their ions calculated. The following 

 are some of Ostwald's results : — 



Similar tables for univalent kations of the ammonium, 

 methylammonium, etc., series follow, and an immense 

 amount of similar matter will be found in Bredig's paper. 

 The differences for successive additions of CH 2 decrease as 

 we ascend the series ; the ionic velocity is hence described 

 as a "Convergent additive property". In general, as it is 

 natural to expect, compound ions travel more slowly than 

 elementary ones, but no very simple relations can be traced, 

 as the nature as well as the number of the compounded 

 atoms exerts an important influence on the velocity. 



The speed with which an ion travels in solution, how- 

 ever, so obviously depends on many factors, that one 

 would only expect a qualitative relation between it and the 

 constitution of the ion. 



The extension of Kohlrausch's theory to solvents other 

 than water, a first attempt at which is described above, and 

 the investigation of aqueous solutions of abnormally low 

 conductivity, seem the most promising fields for future work. 

 Most interesting information about the existence and nature 

 of complex ions ought to be thus obtained and light thrown 

 on the whole subject of solution and electrolysis, for it is by 

 the study of apparent exceptions that we learn the full scope 

 and limitations of a new theory. 



W. C. Dampier Whetham. 



