THEORETICAL OBSERVATIONS. 143 



to this copper an increased tendency to unite with the acid, it will 

 attract the acid from the copper in solution by virtue of this in- 

 creased attraction. Suppose two wires coming from a battery are 

 placed in a solution of sulphate of copper, thus (fig. 51) : the double 

 row representing the compound atoms of sulphate of copper forming 

 the electrolyte : C C the copper or positive element, and SO 4 the 

 sulphuric acid or negative element of the solution. The two single 

 rows, C C, &c., at each end of the double row, represent the wire, 

 or solid conductors of the electricity, from the battery to the decom- 

 position cell : the last particle of the single rows p n nearest the 

 double row may be viewed as the electrodes. The sulphuric acid, 

 SO 4 , and the copper C, in solution, are held together by their affi- 

 nity for each other. 



Now let it be supposed that an equivalent of electricity leaves 

 the positive terminal of the battery P, and passes along the solid 

 particles of the conductor, that particle upon which the electricity 

 is, must be for the time in a higher state of excitement than the 

 other particles. When the electric current comes to the last par- 

 ticle of the solid chain p, which is in contact with the electrolyte, 

 its increased excitement causes it to attract and combine with the 

 acid particle SO 4 nearest it ; the electricity being dynamic, passes 

 to the first basic particle Cl, giving it an exalted excitement, which 

 causes it to unite with the acid particle S0 4 2, the electric force pass- 

 ing to C2, which becomes excited in turn, and takes the particles 

 S0 4 3 ; and so on through the chain till the last particle Co, which, 

 having no further acid to combine with, gives its electricity to the 

 solid conductor, or electrode n, and passes along to the battery, the 

 particle C5 being thus left adhering to the solid chain of par- 

 ticles, or electrode. 



By this we observe that every equivalent of decomposition will 

 carry an equivalent of acid to the positive electrode, without taking 

 the metallic element to the other or opposite electrode. This is 

 exactly the facts of the case, the result that takes place in all solu- 

 tions undergoing decomposition by the current, and also in the 

 battery between the zinc and copper. 



