Electrolytic Intensity required for Water, S^c, 277 



and these at last completed the metallic communication ; and 

 at the same time that they transmitted a more powerful cur*- 

 rent than the fused chloride, they proved that electro-chemical 

 decomposition of that chloride had been going on. Hence it 

 appears, that the current excited by dilute sulphuric acid be- 

 tween zinc and platina, has an intensity above that required 

 to electrolyze the fused chloride of silver when placed between 

 platina electrodes, although it has not intensity enough to de- 

 compose chloride of lead under the same circumstances. 



981. A drop oi "water placed at a instead of the fused chlo- 

 rides, showed as in the former case (970.), that it could con- 

 duct a current unable to decompose it, for decomposition of 

 the solution of iodide at b occurred after some time. But its 

 conducting power was much below that of the fused chloride 

 of lead (978.). 



982. Fused nitre at a conducted much better than water : 

 I was unable to decide with certainty whether it was electro- 

 lyzed, but I incline to think not, for there was no discolora- 

 tion against the platina at the cathode. If sulpho-nitric acid 

 had been used in the exciting vessel, both the nitre and the 

 chloride of lead would have suffered decomposition like the 

 water (906.). 



983. The results thus supplied of conduction without de- 

 composition, and the necessity of a certain electrolytic inten- 

 sity for the separation of the ions of different electrolytes, are 

 immediately connected with the experiments and results given 

 in § 10. of the Fourth Series of these Researches (418. 423. 

 444. 449.). But it will require a more exact knowledge of 

 the nature of intensity, both as regards the first origin of the 

 electric current, and also the manner in which it may be re- 

 duced or lowered by the intervention of larger or smaller 

 portions of bad conductors, whether decomposable or not, 

 before their relation can be minutely and fully understood. 



984. In the case of water, the experiments I have as yet 

 made, appear to show, that when the electric current is re- 

 duced in intensity below the point required for decomposition, 

 then the degree of conduction is the same whether sulphuric 

 acid, or any other of the many bodies which can affect its 

 transferring power as an electrolyte, are present or not. Or, 

 in other words, that the necessary electrolytic intensity for 

 water is the same whether it be pure, or rendered a better 

 conductor by the addition of these substances ; and that for 

 currents of less intensity than this, the water, whether pure 

 or acidulated, has equal conducting power. An apparatus, 

 fig. 12, was arranged with dilute sulphuric acid in the vessel ^, 



