THEORY OF GALVANISM. 



diminishes in the successive portions of water, 

 until at length, in the middle of the vessel, the 

 I fluid is in a neutral state. 

 Decompo- Now if we dissolve a quantity of a neutral salt 

 in this water, we find that the acid particles dif- 

 fuse themselves through the water which is posi- 

 tively electrified, and the alkaline particles through 

 that which is negatively electrified. This is well 

 illustrated in the experiments of Sir H. Davy, 

 where the water was tinged with litmus and tur- 

 meric ; for it was found that the intensity of the 

 effect produced on the colours, and consequently 

 the quantity of acid and alkali contained in the 

 water, was greatest near the wires, and diminished 

 until it arrived at the centre, where the effect 

 ceased. The transfer of the acid to the neigh- 

 bourhood of the positive wire may, therefore, with 

 greater probability, be ascribed to its being at- 

 tracted by the positively electrified water, than to 

 the positive wire itself; for it does not attach itself 

 immediately to the wire, but it diffuses itself 

 through the water, in proportion to the electrical 

 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, conjecture, according to Sir H. 

 Davy's hypothesis, that it is owing to the attrac- 

 tion which subsists between oxygenated substances 

 and positive electricity, as the acquisition of this 

 electricity seems to be the only change which the 

 water has experienced. 



