94 
that the characteristics of the added salts in this photocatalysis are 
evidently intimately connected witb the electric charges of the ions 
and with their mutual electrostatic actions upon each other. 
If the relations found here, should indeed appear to be generally 
valid after the investigations have been extended over a much 
greater number of cases of photocatalysis, it would perhaps appear to 
be possible to give a theoretical explanation of all these peculiarities 
and more particularly of the occurrence of a maximal catalysis by salts, 
starting with the views about the nature of strong electrolytes and their 
abnormal behaviour, as developed in recent times by BJerrum }), 
Grosn *), Noyes *), and others; which views in every case, however, 
would involve a complete break with the electrolytic dissociation- 
theory of ARRHENIUS, at present still almost universally adopted. 
Perhaps one of us will return to this question again in future, 
after a more detailed experimental investigation of this kind has 
been made. 
Laboratory for Inorganic and Physical Chemistry 
of the University. 
Groningen, May 1920. 
1) N. BJERRUM, Zeits. f. Elektrochemie, 24, 321, (1918); Zeits. f. anorg. Chem. 
109, 275, (1919). 
*) |. C. GHosH, Journ. Chem. Soc. London, 113. 449, 627, 707, (1918). 
3) A. A. Noyes and Mc. Innes, Journ. Amer. Chem. Soc. 42, 239, (1920). 
