THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[THIRD SERIES.] 



FEBRUARY 1850. 



IX. On the Electromotive Force of Gases. 

 By W. Beetz, Ph.D.* 



INVESTIGATIONS upon the measurement of the elec- 

 tromotive force of gas batteries are still wanting. The only 

 experiments which aim at quantitative determination, are those 

 in which Grove f measured the change in the volumes of the 

 gases contained in the tubes of the battery. As a rule, the 

 diminution of the volumes was found greater in proportion 

 to the activity of the current produced by the gas. If, how- 

 ever, we require to draw any conclusion regarding electrical 

 excitation from this measurement, the hypothesis of Grove, 

 .viz. that the combination of the two gases used is the source of 

 the electricity, and hence the circuit produces no effect when 

 the gases have no chemical affinity for each other, must first 

 be proved. Even then much deception might occur in con- 

 sequence of secondary actions, such as were observed by 

 Grove himself, so that in this manner we should never be able "I 



to obtain values which could in any way be regarded as mea- ^ 



sures of the electromotive force of gas batteries. Moreover, 

 in consequence of the great inconstancy of gas batteries, at C 



least with the use of most gases, experiments made with bat- 

 teries which have remained closed for a long time consecu- 

 tively, only give very dubious results, because with many of 

 them the polarization entirely renders insensible the original ■ 



electromotive force. Even in the case of those which are ap- 5, 



parently the most constant, those where hydrogen and oxygen, £ 



and hydrogen and chlorine are used, the original force is | 



quickly diminished ; the polarization cannot however here at- C 



tain any very considerable value, because the gases set free by | 



* From PoggendorfTs Jnnalen, vol. Ixxvii. p. 493. "•«'' «-i ""Sj 

 t Phil.Tians. 1843, part. 2. p. 91. [See also Phil. Mag. vol. xxiv. p. 268.]-^ ^ 



Phil. Mag. S. 3. Vol. 36. No. 241. Feb. 1850. G 



