260 Dr. Faraday's Experimental Researches in Electricity. 



charcoal, resembling the brightness of the voltaic discharge 

 on such surfaces. When the discharge of the unretarded 

 electricity was taken upon charcoal, it was bright upon both 

 the surfaces, (in that respect resembling the voltaic spark,) 

 but the noise was loud, sharp and ringing. 



335. I have assumed, in accordance, I believe, with the 

 opinion of every other philosopher, that atmospheric electri- 

 city is of the same nature with ordinary electricity (284.), and 

 I might therefore refer to certain published statements of che- 

 mical effects produced by the former as proofs that the latter 

 enjoys the power of decomposition in common with voltaic 

 electricity. But the comparison I am drawing is far too ri- 

 gorous to allow me to use these statements without being fully 

 assured of their accuracy; and I have no right to suppress 

 them, because, if accurate, they establish what I am labour- 

 ing to put on an undoubted foundation, and have priority to 

 my results. 



336. M. Bonijol of Geneva* is said to have constructed 

 very delicate apparatus for the decomposition of water by 

 common electricity. By connecting an insulated lightning 

 rod with this apparatus, the decomposition of the water pro- 

 ceeded in a continuous and rapid manner even when the elec- 

 tricity of the atmosphere was not very powerful. The appa- 

 ratus is not described ; but as the diameter of the wire is men- 

 tioned as very small, it appears to have been similar in con- 

 struction to that of Wollaston (327.) : and as that does not 

 furnish a case of true polar electrochemical decomposition 

 (328.), this result of M. Bonijol does not prove the identity in 

 chemical action of common and voltaic electricity. 



337. At the same page of the Bibliotheque Universelle, M. 

 Bonijol is said to have decomposed potash, and also chloride 

 of silver, by putting them into very narrow tubes and passing 

 electric sparks from an ordinary machine over them. It is 

 evident that these offer no analogy to cases of true voltaic de- 

 composition, where the electricity only decomposes when it is 

 conducted by the body acted upon, and ceases to decompose, 

 according to its ordinary laws, when it passes in sparks. These 

 effects are probably partly analogous to that which takes place 

 with water in Pearson's or Wollaston's apparatus, and may 

 be due to very high temperature acting on minute portions of 

 matter; or they may be connected with the results in air 

 (322.). As nitrogen can combine directly with oxygen under 

 the influence of the electric spark (324.), it is not impossible 

 that it should even take it from the potassium of the potash, 



* Bibliotheque Universelie, 1830, tome xlv. p. 213, 



