34 



Svante Arrhenius on Electrolytic 



lines of the second ? And these straight lines have to serve 

 alone as the support of the hydration theory ! " Non dantur 

 saltus in naturd " is a proposition which is rightly taken as a 

 motto in every science capable of mathematical treatment. 



Fig. 2. 



When, exceptionally, a sudden break occurs in a series of 

 phenomena, it must be verified with the greatest care both 

 theoretically and practically before its existence is finally 

 accepted. The first curve therefore must be looked upon as 

 the Correct one, because it contains none of those extraordi- 

 narily improbable breaks, until the contrary is proved by a 

 thorough investigation such as does not at present exist. We 

 must therefore reject the idea that the existence of the five 

 straight lines of the second curve is proved. Even, however, 

 if this form were correct, still the conclusions which Prof. 

 Mendelejeff draws would be extremely bold ones. For it 

 might be that the straight lines change their position at 

 higher temperatures (as is the case with internal friction), 

 and thus the singular points where they terminate would 

 indicate the existence of quite other hydrates. This, accord- 

 ing to a note (Ber. deut. chem. Ges. 1886, p. 387), actually' 

 occurs with the point of greatest contraction : — " The greatest 

 contraction g in ] 00 parts by weight at 0° corresponds approxi- 

 mately to ?w = 3, but suffers a considerable displacement with 

 rise of temperature, being at 100° near m = 2." In addition, 

 attention must be drawn to the extreme difficulty of finding 

 the exact positions of these singular points. The experimental 

 material used by Prof. Mendelejeff in his two German publi- 

 cations must be looked upon as insufficient for such purposes. 



ds 

 Strictly speaking, what does the fact that the values of -j- 



