Chemical Action of Atmospheric Electricity. 261 



especially as there would be plenty of potassa in contact with 

 the acting particles to combine with the nitric acid formed. 

 However distinct all these actions may be from true polar 

 electro-chemical decompositions, they are still highly im- 

 portant, and well worthy of investigation. 



338. The late Mr. Barry communicated a paper to theRoyal 

 Society* last year, so distinct in the details that it would seem 

 at once to prove the identity in chemical action of common 

 and voltaic electricity, but that, when examined, considerable 

 difficulty arises in reconciling certain of the effects with the 

 remainder. He used two tubes, each having a wire within it 

 passing through the closed end, as is usual for voltaic decom- 

 positions. The tubes were filled with solution of sulphate of 

 soda, coloured with syrup of violets, and connected by a por- 

 tion of the same solution, in the ordinary manner; the wire 

 in one tube was connected by a gilt thread with the string of 

 an insulated electrical kite, and the wire in the other tube by 

 a similar gilt thread with the ground. Hydrogen soon ap- 

 peared in the tube connected with the kite, and oxygen in the 

 other, and in ten minutes the liquid in the first tube was 

 green from the alkali evolved, and that in the other red from 

 free acid produced. The only indication of the strength of 

 the atmospheric electricity is in the expression, " the usual 

 shocks were felt on touching the string." 



339. That the electricity in this case does not resemble that 

 from any ordinary source of common electricity, is shown by 

 several circumstances. Wollaston could not effect the decom- 

 position of water by such an arrangement, and obtain the gases 

 in separate vessels, using common electricity; nor have any 

 of the numerous philosophers, who have employed such an 

 apparatus, obtained any such decomposition, either of water 

 or of a neutral salt, by the use of the machine. I have lately 

 tried the large machine (290.) in full action for a quarter of 

 an hour, during which seven hundred revolutions were made 

 without producing any sensible effects, although the shocks 

 that it would then give must have been far more powerful and 

 numerous than could have been taken, with any chance of 

 safety, from an electrical kite-string ; and by reference to the 

 comparison hereafter to be made (371.), it will be seen that 

 for common electricity to have produced the effect, the quan- 

 tity must have been awfully great, and apparently far more 

 than could have been conducted to the earth by a gilt thread, 

 and at the same time only have produced the " usual shocks." 



340. That the electricity was apparently not analogous to 



* Philosophical Transactions, 1831, p. 165. 



