

ELECTRICAL RELATIONS. 207 



pole of a galvanic arrangement.* That is, the wire 

 which carries the current from an excited zinc plate 

 has a relation to all bodies, which is directly opposite to 

 that which is exhibited by the wire conveying the cur- 

 rent from, or completing the circuit with, the copper 

 plate. The one, for instance, collects and carries acids 

 and the like, the other the metallic bases. At the 

 extremity of one galvanic wire, placed into a drop of 

 water, oxygen is always liberated ; and at the end of 

 the other, necessary to complete the circuit with the 

 battery, hydrogen is set free. 



It appears necessary, to a clear understanding of 

 what takes place in this experiment, that we should 

 regard each mass, howsoever large, as the representative 

 of a single atom. Nor is this difficult, as the following 

 illustration will show. 



* The appearance of acid and alkaline matter, in water acted 

 on by a current of electricity, at the opposite electriiied metallic 

 surfaces, was observed in the first chemical experiments made 

 with the column of Volta (see Nicholson's Journal, vol. iv. p. 

 183, and vol. iv. p. 261, for Mr. Cruickshank's Experiments ; and 

 Annales de Chimie, torn, xxxvii. p- 233, for those of M. Desormes) : 

 On some Chemical Agencies in Electricity : by Sir Humphry Davy. 

 Philosophical Transactions for 1807. The various theories of 

 electro chemical decomposition are carefully stated by Faraday, in 

 his fifth series of Experimental Researches on Electricity, in which 

 he thus states his own views : " It appears to me that the effect 

 is produced by an internal corpuscular action exerted according 

 to the direction of the electric current, and that it is due to a force 

 either superadded to or giving direction to the ordinary chemical 

 affinity of the bodies present. The body under decomposition 

 may be considered as a mass of acting particles, all those which 

 are included in the course of the electric current contributing to 

 the final effect ; and it is because the ordinary chemical affinity 

 is relieved, weakened, or partly neutralized by the influence of the 

 electric current in one direction parallel to the course of the 

 latter, and strengthened or added to in the opposite direction, that 

 the combining particles have a tendency to pass in opposite- 

 courses." 



