GENERAL SUMMARY. 



(4) The chemical action in a cell is also diminished by 

 increasing the distance from each other in the exciting fluid of 

 the positive and negative metals. 



(5) The lines of chemico-polar molecules in the exciting fluid 

 should be repulsive of each other, like lines of magneto-polar 

 elements, as illustrated in the mutual repulsion and divergence 

 of the threads of steel filings which attach themselves to the 

 pole of a magnet (Fig. 9.) That the lines of induction do diverge 

 greatly in the acid, starting from the zinc as a centre, is placed 

 beyond doubt by many experiments of Mr. Daniell. A small 

 ball of zinc suspended in a hollow copper globe filled with acid, 

 is the arrangement in which this divergence is least restrained, 

 and was found to be the most effective form of the voltaic circle. 

 When the copper too, is a flat plate, and wholly immersed in 

 the acid, the back is found to act as a negative surface, as well 

 as the face directly exposed to the zinc, showing that the lines 

 of induction in the acid expand and open out from each other, 

 some bending round the edge of the copper plate and terminating 

 their action, after a second flexure, on its opposite side. To 

 collect these diverging lines, the surface of the copper may be 

 increased with advantage to at least four times that of the 

 zinc. 



(6) The polar chains of molecules, in the connecting wires and 

 other metallic portions of the circle, must be equally repulsive 

 of each other. Hence the small size of the negative plates in 

 the active cells, and of the platinum plates in the cell of decom- 

 position, and the thinness of the connecting wires, are among 

 the circumstances which dimmish the number of polar lines 

 that can be established, and impair the general efficiency of a 

 battery. 



6. The effect of multiplying the active cells in a battery is 

 not to increase the number of polar chains, or quantity of in- 

 duced particles, but to increase the intensity of the induction in 

 each chain ; although this increase in intensity generally aug- 

 ments the quantity also, in an indirect manner, by overcoming 

 more or less completely such obstacles to induction as have 

 been enumerated. 



7. The intensity of the induction, also, is much greater with 

 some zincolytes than others. Thus a single pair of zinc and 

 platinum plates excited by dilute sulphuric acid, decompose 

 iodide of potassium, proto-chloride of tin and fused chloride of 



