128 On the TYansmission of Electrolysis across Glass, 



from the outer vessel and tapped, minute bubbles rose from the 

 interior surface. When a tolerably thick test- tube was used 

 instead of the Florence flask, a very slight effect of electrolysis 

 could be detected ; and when the outer wire was removed to a 

 short distance from the surface, sparks passed, but not of half the 

 length of those with the Florence flask. When, however, a 

 large phial of somewhat greater contents- than the Florence flask 

 was used, the effects were the same as with the latter, showing, 

 as I expected, that surface is an important element in the success 

 of the experiment. 



There seems little doubt from the above experiments that the 

 electrolysis was effected by induction across the thin glass of the 

 Florence flask ; and its cessation after a time, and recurrence after 

 interruption of the current, would seem to indicate something 

 like a state of charge or polarization of the surface of the glass. 



Whether the bubbles which arose from the interior surface of 

 the glass were the effect of electrolytic action or mere air-bubbles, 

 cannot be affirmed with certainty; but as there was distinct 

 evolution from the platinum wires, the corresponding elements 

 must have been either dissolved, evolved, or deposited somewhere, 

 and the most probable place of evolution would be the surface of 

 the glass. If this be so, the glass would act in effect just as an 

 interposed plate of inoxidable metal, though the one acts by in- 

 duction, the other by conduction. 



The oxygen and hydrogen may, however, be spread over the 

 surface of the glass without evolution in the form of gas ; and 

 when the glass is, so to speak, coated by the elements, decom- 

 position would cease. 



The quantity of gas in the above experiment was too small 

 for analysis; and in all probability, could it have been examined, 

 some mixed gas would have been found to have been eliminated 

 from each electrode. When, however, there is a small interrup- 

 tion in the secondary circuit of RuhmkorfFs coil, producing a 

 rapid succession of sparks, I have found that between electrodes 

 in the same circuit true polar decomposition takes place, and a 

 galvanometer is steadily deflected according to the direction of 

 the current, while without such interruption the movements of 

 its needle are most irregular. I therefore repeated the experi- 

 ment of interposed glass with an interruption in the circuit, and 

 found that electrolysis took place as before; and in this case I 

 have little doubt was true polar decomposition. 



Although I failed with thirty cells of the nitric acid battery, 

 I should fully expect that a battery of very high intensity, such 

 as the 500 cells nitric acid, or the water battery of Mr. Gassiot, 

 would produce effects of electrolysis across glass without the use 

 of the coil. 



