334 VOLTAIC ELECTEICITY. [SECT. xxix. 



of electricity of uniform power, but it is also of very feeble 

 force. The current is produced by the chemical combina- 

 tion of an acid with an alkali. 



Metallic contact is not necessary for the production of 

 Voltaic electricity, which is entirely due to chemical action. 

 The intensity of the Voltaic electricity is in proportion to 

 the intensity of the affinities concerned in its production, 

 and the quantity produced is in proportion to the quantity 

 of matter which has been chemically active during its evo- 

 lution. Dr. Faraday considers this definite production to 

 be one of the strongest proofs that the electricity is of 

 chemical origin. 



Galvanic or Voltaic, like common electricity, may either 

 be considered to consist of two fluids passing in opposite 

 directions through the circuit, or, if the hypothesis of one 

 fluid be adopted, the zinc end of the battery may be sup- 

 posed to have an excess of electricity, and the copper end 

 a deficiency. Hence, in the latter case, the zinc is the posi- 

 tive end of the battery, and the copper the negative. 



Voltaic electricity is distinguished by two marked cha- 

 racters. Its intensity increases with the number of plates 

 its quantity with the extent of their surfaces. The most 

 intense concentration of force is displayed by a numerous 

 series of large plates, light and heat are copiously evolved, 

 and chemical decomposition is accomplished with extra- 

 ordinary energy ; whereas the electricity from one pair of 

 plates, whatever their size may be, is so feeble that it gives 

 no sign either of attraction or repulsion ; and, even with a 

 battery consisting of a very great number of plates, it is dif- 

 ficult to render the mutual attraction of its two wires sen- 

 sible, though of opposite electricities. 



The action of Voltaic electricity differs in some respects 

 materially from that of the ordinary kind. When a quantity 

 of common electricity is accumulated, the restoration of equi- 

 librium is attended by an instantaneous violent explosion, 

 accompanied by the development of light, heat, and sound. 



