1814.] On the Hypotheses of Galvanism. 89 



immersed in the water, in consequence of tlieir attraction for its 

 constituents, they each begin to act upon tlie parts contiguous to 

 them, A attractiug the oxygen, and B the hydrogen. But no 

 sooner have the wires decomposed tlie water, in coiisi^queuce of 

 their attraction for its constituents, than the substances attracted are 

 disengaged, wliile the otiier constituent remains in the water ; so 

 that the fluid on tlie side near the positive wire will contain an 

 excess of hydrogen ; and that near the negative wire, of oxygen. 

 These liberated |)articles of hydrogen and oxygen are supposed to 

 be repelled from the wires near which they are situated, to meet in 

 the centre of the fluid, combine again, and reproduce watef. This, 

 I believe, will be admitted to exhibit a fair view of tlie hypothesis 

 as detailed by Sir H. Davy; and yet, 1 confess, it has always 

 appeared to me to involve many improbatiilities, if not contradic- 

 tions. The fundamental principle upon which it rests is, that the 

 positive wire attracts oxygen ; and the negative, hydrogen ; and, in 

 consequence of these attractions, that the water is decomposed ; yet 

 the effect produced upon the water is, that tlie oxygen is discharged 

 by the positive wire and the hydrogen retained, and tlie hydrogen 

 discharged from the negative wire and the oxygen retained. But a 

 repulsive force is supposed to be exerted here as well as an attractive 

 one, and the hydrogen is repelled from the positive wire at the same 

 time that the oxygen is attracted by it ; yet the fame peculiarity 

 occurs here as before, the substance tiiat is repelled by the wire is. 

 retained in the water, while that which is attracted by it is dis- 

 charged. It follows, according to this hypothesis, that the different 

 parts of the water must be in diHerent states of clicmical combina- 

 tion, the part near the positive wire containing an excess of 

 hydrogen, and that near the negative wire an excess of oxygen : 

 and the hydrogen and oxygen are here in an uncomlMued stiito, and 

 therefore they might be expected each of them to exhibit tlieir 

 specific chemical propeities, or at least to affect the chemical com- 

 position uf the water with which they are united. This h\poiliesis' 

 necessarily supposes the existence of two currents through the fluid, 

 one of hydrogen from the positive, and the other of ox\gen from 

 the negative wire, which meet in the centre, and are there mutually 

 destroyed. These opjxisite currents depend partly on the lepulsion 

 exercised by the wires on the constituents of the water, and paitly 

 on their attraction for each other. Hence it may be infeared that 

 if some substance were presented to them in their course, to which 

 they had a stronger attraction than that which they possess for each 

 other, the water would not be re])roduced ; and if one of them 

 only was attracted in this way, the other would be discharged. 'J'his 

 will appear nujrc plain if we suppose that the two wires terminate 

 in two separate quantities of water, that are connecled by a tube or 

 any fibrous substance, so as to form a communication between the 

 two |K)nions. The recomposition of tlie v^ater will take place only 

 in this tube, which is supposed to be exactly in the centre, and the 

 whole of the fluid in contact with the jmsiiive wire will be hydro- 



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