388 DR. MEYER WILDERMAN ON THE CHEMICAL STATICS AND DYNAMICS OF 
tion,’ Liverpool, 1896. Since 1896 I often made use of the above results in many of my 
publications (see ‘Report Brit. Ass.,’ Liverpool, 1906, the ‘ Zeitschr. physik. Chemie,’ 
vol. 30, pp. 348-368, 1899, ‘Phil. Mag.,’July, 1901, pp. 50-90). The very same 
equation (and for the same kind of reaction) later on Noyes and Whitney (‘ Zeitschr. 
physik. Chemie,’ vol. 23, p. 689, 1897), and more recently Nernst and Brunner 
(‘Zeitschr. physik. Chemie,’ vol. 47, pp. 50-102, 1904), confirmed in their investigations 
of the speed of solution of salts. The equation used by Noyes and Whitney (using 
• dt 
the same notation) is-p = c' (t 0 —t) (they are taking the velocity constant per unit 
(IT 
dt D 
surface); the equation used by Nernst and Brunner is -j- = 2* (t 0 —t) or=C % t (t 0 —t), 
D 
where is also a constant as my C is. 
o 
So far they only confirm the general law 
which was given and established by me before Noyes and Whitney, and long before 
Nernst and Brunner (also for solution and separation of salt, &c., &c.). 
As to their attempt to explain the constant C by diffusion, it entails a number of 
hypotheses, which appear to me to be quite incompatible with experience. As none 
of their fundamental hypotheses have been, in my opinion, shown to exist by any 
reliable experiments, they seem to me at present only as arbitrary interpretations 
of qualitative results. My law has been shown to he general, it gives the velocity 
of all molecular transformations between different parts of the heterogeneous system, 
including those (such as melting of ice, separation of ice from overcooled water, &c.) 
where diffusion cannot possibly enter into consideration. It follows, therefore, that a 
law of such a wide scope cannot be based upon diffusion, and that no more should 
be read in the content of my equation than it is clearly given by its form. 
( f ) Velocity of Chemical Reaction in Heterogeneous Systems, produced by and going 
on only under the Action of Light, evidently follows after the Induction Period 
has passed, the Laws deduced by the Author for Velocity of Chemical Reaction 
in Heterogeneous Systems in the Dark. 
We have thus shown, on the one hand, that the velocity of chemical reaction in 
homogeneous systems under the action of light follows, after the induction period, 
the law of mass action, as in the dark, and, on the other hand, the equations for the 
induction and deduction periods in galvanic cells make it highly probable that the 
speed of molecular or physical transformations between different parts of the 
heterogeneous system under the action of light must follow the same law as in the 
dark. It follows from this that the laws governing velocity of chemical reaction in 
heterogeneous systems under the action of light, must, after the induction period has 
passed, follow the laws which I deduced for this region in the dark. In ‘ Zeitschr. 
physik. Chemie,’ 1899, vol. 30, pp. 371-382, and ‘ Phil. Mag.,’ 1902 (6) 4, pp. 
468-489, I showed that the laws for velocity of chemical reaction in heterogeneous 
