6\6 SCIENCE PROGRESS 



Society in the following year (written before I had been able to 

 procure Arrhenius's paper) I took definite exception to the ionic 

 dissociation hypothesis, even in the mild form postulated by 

 Clausius. I also took exception, in the most positive manner 

 possible, to the Arrhenius hypothesis in several of the reports 

 published between 1885 and 1890 by the committee appointed 

 to consider Electrolysis in its Physical and Chemical Bearings. 

 At Leeds, again, in the discussion on the theory of solution, I 

 protested against the acceptance of the ionic equation 



H + CI + K + OH = K + CI + H.,0 



in the following terms : 



Such a conclusion, although undoubtedly necessary and 

 logical from the dissociationist's point of view, involved the 

 admission that hydrogen chloride and water were compounds 

 of a totally different order ; that these two hydrides were so 

 different that while that of chlorine underwent practically 

 complete dissociation, that of oxygen remained practically un- 

 changed. Chemists, however, were in the habit of teaching that 

 chlorine and oxygen were comparable elements and the facts of 

 chemistry appeared to afford the strongest evidence that hydro- 

 gen chloride and oxide were in all ways comparable compounds. 

 Moreover, the behaviour of the two compounds at high tem- 

 peratures afforded no grounds for any such belief in the 

 instability of the one and the stability of the other." 



To this Ostwald made reply as follows : 



Professor Armstrong has declared that the dissociation 

 theory of electrolytes is unacceptable to chemists. As far as 

 I am aware, there exists nowhere a real contradiction between 

 chemical facts and the dissociation theory but this theory only 

 runs against all the time-honoured feelings of chemists. As 

 feelings, although very powerful things, are at least variable 

 with time and custom, it is to be expected that they will change 

 sooner or later. The time is not very long past when the 

 assumption that, in the vapour of ammonium chloride, hydro- 

 chloric acid and ammonia, which have " so great an affinity for 

 each other," should exist separately from one another, ran in 

 quite the same manner against the feelings of chemists. Now 

 we are accustomed to this conception and in the same manner 

 in a year or two chemists will speak as quietly of the free ions 

 as they now speak of the uncombined mixture of hydrochloric 

 acid and ammonia in the gaseous state. . . . 



Professor Armstrong has asked why water does not split 

 into ions, while hydrogen chloride, a body similar to water, 



