On the Intensity necessary for Eledrolyzation, 2'7S 



could really pass through, and yet not decompose an electro- 

 lyte (910.). 



968. An arrangement (fig. 12.) was made, in which two 

 glass vessels contained the same dilute sulphuric acid, sp. gr. 

 1*25. The plate z was amalgamated zinc, in connexion, by 

 a platina wire «, with the platina plate e ; b was a platina wire 

 connecting the two platina plates P P^; c was a platina wire 

 connected with the platina plate P". On the plate e was 

 placed a piece of paper moistened in solution of iodide of 

 potassium : the wire c was so curved that its end could be 

 made to rest at pleasure on this paper, and show, by the evo- 

 lution of iodine there, whether a current was passing ; or, 

 being placed in the dotted position, it formed a direct com- 

 munication with the platina plate <?, and the electricity could 

 pass without causing decomposition. The object was to pro- 

 duce a current by the action of the acid on the amalgamated 

 zinc in the first vessel ; to pass it through the acid in the se- 

 cond vessel by platina electrodes, that its power of decom- 

 posing water might, if existing, be observed ; and to verify 

 the existence of the current at pleasure, by decomposition at 

 e, without involving the continual obstruction to the current 

 which would arise from making the decomposition there con* 

 stant. The experiment, being arranged, was examined, the 

 existence of a current shown by the decomposition at e, and 

 then left with the end of the wire c resting on the plate e^ so 

 as to form a constant metallic communication there, 



969. After several hours, the end of the wire c was replaced 

 on the test paper at e: decomposition occurred, and the proof 

 of a passing current was therefore complete. The current 

 was very feeble compared to what it had been at the begin- 

 ning of the experiment, because of a peculiar state acquired 

 by the metal surfaces in the second vessel, which caused them 

 to oppose the passing current by a force which they possess 

 under these circumstances (1040.). Still it was proved, by 

 the decomposition, that this state of the plates in the second 

 vessel was not able entirely to stop the current determined in 

 the first, and that was all that was needful to be ascertained 

 in the present inquiry. 



970. This apparatus was examined from time to time, and 

 an electric current always found circulating through it, until 

 twelve days had elapsed, during which the water in the se- 

 cond vessel had been constantly subject to its action. Not- 

 withstanding this lengthened period, not the slightest appear- • 

 ance of a bubble upon either of the plates in that vessel oc- 

 curred. From the results of the experiment, 1 conclude that 

 a current had passed, but of so low an intensity as to fall be- . 



Third Series. Vol. 6. No. 34. Jpril 1835. 2 N 



