SVANTE AEEHENIUS WALKER 717 



Angstrom was so great that, beyond the apparatus for elementary 

 students, there was little else in the department but instruments for 

 exact measurements of wave lengths, a subject for which Arrhenius 

 had no liking. Thalen did not encourage independent work in his 

 laboratory, and Arrhenius was forced to look about for some other 

 opportunity to begin physical research. He, with a fellow student, 

 repaired in September, 1881, to Stockholm with the intention of 

 working in the laboratory of Erik Edlund, professor of physics to 

 the Swedish Academy. Edlund gave them a hearty welcome, and 

 they began by assisting him in his work on electromotive forces in 

 the spark discharge. In the spring of the following year Arrhenius 

 started his first independent research on the decay of galvanic polar- 

 ization with time, an account of which was published in the Bihang 

 of the Swedish Academy in 1883. From this he passed to the 

 measurement of the conducting power of electrolytic solutions. 



It is of interest to inquire into the reasons which induced Arrhenius 

 to take up this line of work. The pursuit of science, like other 

 human activities, is not exempt from the prevalence of fashions. 

 At the period under consideration the study of the properties of 

 solutions was in the air. Van 't Hoff was busy tracing the analogy 

 between dilute solutions and gases; Raoult was developing empirical 

 methods for the determination of the molecular weights of dissolved 

 substances; Kohlrausch had just perfected his telephone method for 

 determining electrolytic conductivities ; Ostwald was working at reac- 

 tion velocities and the affinities of acids and bases in aqueous solution. 

 Arrheniu,s yielded to the same influence, but curiously enough what 

 led him to the investigation of electrolytic solutions was not directly 

 concerned with the conducting substances themselves. He tells us 

 that Cleve in his lectures had emphasized the impossibility of ascer- 

 taining the molecular weights of substances, .such as sugar, which 

 could not be volatilized without decomposition. Arrhenius rightly 

 recognized that this was a great drawback, by the removal of which 

 a considerable advance in chemistry would be rendered possible. He 

 was unaware of Raoult's work, and thought that some light might 

 be thrown on the molecular weight of dissolved substances by meas- 

 urements of electrolytic conductivity. He knew that when some of 

 the water of a conducting solution was replaced by more complex 

 nonconducting substances, such as alcohol, the conductivity was low- 

 ered, and he thought it might be feasible to deduce the molecular 

 weight of this added substance from its effect on the conductivity. 

 He had not proceeded far with his measurements, however, when he 

 recognized that the state of the conducting salt was the matter of 

 primary importance. 



The theory of electrolysis and electrolytic solutions was also de- 

 cidedly in the air at the same period. The chains of Grotthus, the 



