Royal Society. 39 



tendant on the different modes in which electricity has been excited 

 and supplied. Thus no difference was found to exist in the mode in 

 which a Leyden battery charged with ordinary electricity, and a vol- 

 taic battery, were discharged, when the comparison was made by 

 means of fine points, nicely arranged and approximated, either through 

 air of the ordinary temperature, or through heated air, such as the 

 flame of a spirit-lamp, interposed between the points. 



By the term current, the author designates any progressive change, 

 of whatever nature it may be, in the electric state,' whether consisting 

 in the motion of one electric fluid in a particular direction, or of two 

 fluids in contrary directions : and by the term arrangement, he under- 

 stands a local adjustment of particles, or fluids, or forces, not pro- 

 gressive. 



By ordinary electricity, he understands that which can be obtained 

 from the common electrical machine, or from the atmosphere, or by 

 pressure, or cleavage of crystals, or similar mechanical operations -, 

 its character being that of great intensity, and the exertion of attrac- 

 tive and repulsive forces, not merely at small but also at considerable 

 distances. The parallel between voltaic and ordinary electricity is 

 then pursued by the production of evidence that those attractions 

 and repulsions, which were thought to characterize the latter, are 

 exhibited also by the former ; and that, on the other hand, ordinary 

 electricity, when in motion, gives rise to an increase of temperature, 

 to magnetic phenomena, to chemical decompositions, to physiological 

 impressions, and to luminous appearances, precisely of the same kind 

 as those which had been supposed to be the peculiar effects of voltaic 

 electricity. The experiments of Mr.'Colladon, which seemed to show 

 that a stream of common electricity has power to produce the deflexion 

 of a magnet, — a conclusion which has hitherto rested on the single 

 testimony of that experimentalist, — have been repeated and extended 

 by Mr. Faraday, who completely confirms their accuracy, and the 

 truth of the result that had been obtained from them. The author 

 succeeded in making common electricity assume more of the charac- 

 ters of voltaic electricity, by availing himself of the retarding power 

 of bad conductors interposed in the electric circuit. In this way he 

 easily succeeded in obtaining the same decisive evidence of chemical 

 action by common electricity as Dr. Wollaston had done in his expe- 

 riment. But Mr. Faraday considers the experiment in which water 

 is decomposed by this power, as affording no proof of electro-chemical 

 agency ; because, as Dr. Wollaston had pointed out, both oxygen 

 and hydrogen are evolved at each of the points of the interrupted 

 circuit, and not separately at the respective poles. The author re- 

 gards the amount of electro-chemical decomposition as being pro- 

 portional, not to the intensity, but to the quantity of electricity trans- 

 mitted. It is not effected by electricity passed from the machine in 

 sparks, although these tend to decompose water into its constituent 

 elements. Some experiments of Bonijol on the decomposition of 

 water by atmospherical electricity, are commented on by the author, 

 who considers them as analogous to the experiment of Dr. Wollaston 

 already referred to. Mr. Faraday also makes some remarks upon 

 Mr. Barry's paper in the Philosophical Transactions for 1831, and 



