THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JANUARY 1879. 



I. On the Excitation of Electricity at the Contact of Solids and 

 Gases. By W. Beetz*. 



WHEN publishing my first experiments on the electro- 

 motive forces of gas batteries, I expressed my ideas re- 

 specting the place at which the seat of the difference of tension 

 produced was to be sought f. Grove had assumed that it was 

 the place of contact of the platinum, gas, and liquid \. I did 

 not admit the universal correctness of that aaetjmption : it is 

 certainly not true for gases which, like chlorine, strongly ab- 

 sorb water ; for a platinum plate entirely immersed in a liquid 

 containing chlorine behaves, in respect of its electricity, very 

 differently from a plate of platinum immersed in a liquid free 

 from chlorine. I showed that what happens with other gases 

 may be regarded as precisely similar ; only it is the less di- 

 stinctly manifested the less soluble they are in the liquid. 

 The upper part of a platinum plate, enveloped in hydrogen, I 

 covered with an insulating layer, so that the free platinum 

 was entirely covered by the liquid, and yet it preserved a real 

 gaseous element, certainly of somewhat less electromotive 

 force than if the upper end of the platinum had been directly 

 surrounded by the gas. I have in the place above cited given 

 my views respecting the reasons for this difference. Gaugain 

 subsequently arrived at the conclusion that the platinum acts 

 only upon the gases dissolved in the liquid §. A platinum 



* Translated from Wiedemann's Annalen, 1878, No. 9, vol. v. pp. 1-20. 

 t Pogg\ Ann. vol. lxxvii. p. 505. J Phil. Trans. 1813, pt. 2, p. 97. 

 § Comptes Itendus, t. lxiv. p. 364 (1867). 



Phil. Mag. S. 5. Vol. 7. No. 40. Jan. 1879. B 



