485 



give ail example of' . the view tliat at least in defuute cases, ioiii- 



sation- and dislocation-potentials are not only decisive with regard 



to the possibility of reaction, imt also with regard to reaction 



velocity and reaction temperature. 



Pkhhin sees photo-chemical action in every chemical action. Our 



insight into the structure of the atom makes us lealize that the 



fundamental feature is the displacement of the electrons in it. This 



displacement may be brought about by radiation, but also in various 



other ways. Accordingly it is not justiliable to assign merely apart 



to light in the explanation of chemical action; other forms of energy 



also make their influence felt. In connection with the conception of 



an interaction between the different forms of energy, the possibility 



might, however be considered of a derivation, even though it be a 



critical energy supply 



formal one, of the relation ^^ ^ = constant from 



reaction temperare 



the laws of radiation, in which case the directing lines given by 



R. C. Toi.MAN ') and E. K. Rideai, ') .should be taken into account. 



This will be treated elsewhere. 



Dordrecht, June 26"' 1923. 



N^ote at the correction. From recent determinations of the electron- 

 affinity of some electronegative elements as well as from known 

 electro-chemical date may be deduced — as will be shown elsewhere 

 — that the addition potential of an electron to an atom of oxygen 

 can at most be about 2 volt. This value confirms the assumptions 

 given sub /" and jiistilies the neglect of the addition potential of 

 the valency-electron to the oxygen, the value of which in our cases 

 (as a rule) can only be little. 



July, 4'i>, '23. 



>) R. C. Tolman. Journ. Araer. Chem. Soc. 42, 2506 (1921). 

 2) E. K. RiDEAL. Phil. Mae. 42, 156 (1921). 



