[ 335 ] 
VII. Galvanic Cells Produced by die Action of Light.—The Chemical Statics and 
Dynamics of Reversible and Irreversible Systems under the Influence 
of Light. (Second Communication .) 
By Meyer Wilderman, Ph.D., B.Sc. ( Oxon). 
Communicated by Dr. Ludwig Mond, F.R.S. 
Received June 27, 1905,—Read January 25, 1906. 
[Plates 1-8.] 
Introduction. 
In this communication we devote all our attention to constant reversible galvanic 
cells created by light. Having first shown in § 1 that the E.M.F.’s created by light 
in the combinations of Becquerel and Minchin, or any others, are not surface 
phenomena on the plates of the electrodes, but galvanic, we shall have next to 
establish in § 2 that the E.M.F. created by light represents a new phenomenon, and 
is not an ordinary thermo E.M.F. Having further shown in § 3 that all wave-lengths 
act as actinic rays, we shall then proceed, after the account given of the method 
employed to secure accurate results, to a very detailed study of constant cells rever¬ 
sible in respect of the cation (§ 6) and reversible in respect of the anion (§ 7) carried 
out with the total light of acetylene or arc, or with the total light passing coloured 
screens. A study (in § 5) of the chemical statics and dynamics in constant reversible 
cells created by light, which at the same time enables us to fix aiiy chemical com¬ 
bination of cell into its proper class, must evidently proceed to the research given 
in § 6 and § 7. In § 8 we shall collect from the results given in § 6 and § 7 the 
experimental evidence in support of the physico-mathematical theory of galvanic 
cells given by the author in ‘Roy. Soc. Proc.,’ November, 1904, vol. 74. Finally, in 
§ 9, a short outline will be given of the general laws obtained for chemical statics and 
dynamics under the action of light, of which galvanic cells form only a part. 
VOL. ccvl—a 408. 
31.7.06 
