Peculiar Voltaic Arrangements. 139 



tion in which one of the constituent parts of the electrolyte 

 moves with regard to the substance which chemically acts 

 upon the electrolyte. If the electrolyte be water for in- 

 stance, and its hydrogen happens to recede from the body 

 that operates the composition of water, the current goes along 

 with the hydrogen and we call the body causing the chemical 

 action electro-positive. If, on the contrary, the oxygen of the 

 electrolyte recedes from the substance by means of which 

 chemical action is brought about, the current approaches that 

 substance, and we term the latter electro -negative. Generally 

 speaking, the direction in which the atoms of hydrogen move 

 during the electrolyzation of water is also the direction in 

 which the current circulates, both motions being one and the 

 same thing. After what has been said it cannot surprise us 

 that the chemical decomposition of water caused by chlorine 

 or bromine produces a voltaic effect exactly opposite to that 

 which is obtained by the decomposition of the same electrolyte 

 brought about by the action of zinc. As to the peroxides, it 

 cannot be doubted that their surplus of oxygen acts the same 

 voltaic part with regard to water, as chlorine and bromine do in 

 the cases which have just now been discussed ; but how does it 

 happen, that oxygen, being in a combined state, exerts any tend- 

 ency to unite with the hydrogen that is chemically associated 

 with oxygen ? I tried to answer this puzzling question some 

 time ago in a letter to the editor of the Phil. Mag.: having 

 however ascertained since some facts which do not well agree 

 with my views developed in the paper alluded to, I am inclined 

 to consider the latter as erroneous. As I think it to be a 

 fundamental principle of the theory of galvanism, that any 

 hydroelectric current, even the weakest one, is absolutely de- 

 pendent upon real chemical action, in other terms, that hydro- 

 electric currents and certain chemical actions are the same 

 things, I am forced to admit that the decomposition of per- 

 oxide of lead for instance, which takes place when that sub- 

 stance constitutes a voltaic circle with (acidulated) water and 

 platina, is an immediate action ; that is to say, the immediate 

 effect of the tendency of one proportion of oxygen contained in 

 the peroxide of lead to unite with the hydrogen of water, is just 

 as immediate as the tendency of zinc to combine chemically 

 with the oxygen of water. But such a supposition certainly 

 implies something which seems to be altogether impossible, 

 or at least highly improbable, namely that different portions 

 of oxygen being in different states of combination, are not to 

 be considered as being absolutely identical with each other 

 with regard to their voltaic action or properties. 



A supposition of this kind sounds indeed very strangely, and 



