92 On the Hypotheses of Galvanism. [Feb. 



electrified state of its different parts. If we go farther, and inquire 

 why acids are disposed to be transferred to water which is in a state 

 of positive electricity, we may, I think, fairly conjecture, according 

 to ^il• H. Davy's hypothesis, that it is owing to the attraction which 

 exists between oxygenated substances and positive electricity, as the 

 acquisition of this electricity seems to be the only change which the 

 water has experienced. 



From this view of the subject I am led to conclude, that when 

 the extremities of the pile are connected by water, there are two 

 distinct operations going forwards in the fluid ; the first is the 

 extrication of a quantity of oxygen from the positive wire, in con- 

 sequence of the hydrogen which the electricity requires to enable it 

 to pass through the water, and the subsequent extrication of this 

 hydrogen at the negative wire ; the other is the communication to 

 the water of the electrical state of the wire which is in contact 

 with it J it is to the first of these circumstances alone that the 

 decomposition of the water and the disengagement of the gaseous 

 products are owing, and to the latter alone, the decomposition of 

 neutral compounds, and the transfer of their constituent parts to 

 the different portions of the water. It wdl be admitted, that there 

 b nothing in the nature of these facts which is at all contradictory 

 to the chemical hypothesis ; they are, indeed, so far favourable to 

 it, as tliat they lend us to conclude, that the same kind of effect is 

 carried on between every pair of plates as between tlie two termi- 

 nating wires, except that the electrical fluid having a larger space 

 to pass through, its operations are kept moi:e distinct from each 

 other.* 



A large part of the reasoning in this paper is confessedly hypo- 

 thetical ; but if the hypothesis be a fair deduction from acknow- 

 ledged phenomena, it will be entitled to some consideration. 

 Scientific investigations are seldom performed to much advantage, 

 unless there is some object in view farther than the mere observ- 

 ance of casual phenomena, while a correct hypothesis leads 

 directly to the discovery of truth, by pointing out the track which 

 \vc must pursue in our future experiments. 



* In treating upon the liypotliesis of the Oalvanic pile it would he impossible 

 to omit noticing the elaboraie essavs which hnve been written upon the subject by 

 ivi. De Luc. (a) His experiments are mauy of iheiu very curious and valuable, and 

 to some of his deduction? I fully assent. Yet I am not disposed to coincide with 

 iiim in hii general hypothesis, particularly in that part of it where he endeavours 

 to show that the chemical and electrical etVects of the pile depend upon actions 

 es?enlially dissimilar from each other ; 1 think they may be all referred to a differ- 

 ence either in the quantity, intensity, or velocity of the electric fluid. The 

 experiments prove tli.tt the course of the electricity through water is from the 

 positive to the negative wire, the former disengaging oxygen, and the lattep 

 fiydrngcn, but no attempt is made lo give any explanation of this procws. 



(n) Nich. Jonr, xxvl. and following Toluraes, 



