122 MR CONNELL ON THE ACTION OF VOLTAIC ELECTRICITY 



of an inch fi-om one another. A brisk effervescence ensued from the negative 

 pole, and considerably less from the positive, and the mixed gases were collected 

 over mercury. After twenty to thirty minutes' action, the liquid began to deepen 

 in colour, and when the foUs were examined after nearly an hour's action, the 

 positive foU was found to be fi-inged with white matter, which was afterwards 

 ascertained to be carbonate of potash. In seven and a-half hours, after which time 

 a moderate effervescence was still going on from the negative pole, and none from 

 the positive, the liquid had acquh'ed the colour of Port wine, and after twenty- 

 two hours' action, Avhen a feeble effervescence was still obseiwed, the colour had 

 become a very dark red ; and carbonate of potash was collected at the bottom of 

 the liquid, having doubtless gradually fallen fi*om the positive foil, Avhich was 

 found to be stiU fringed with that salt. When the red solution was evaporated 

 nearly to dryness, re-dissolved in water, and saturated with mm-iatic acid, an 

 abundant precipitation of resinous matter ensued.* 



The hydrogen which was collected diu'ing the second quarter of an hour of 

 the preceding experiment, was found to contain about ^ of oxygen, which had 

 come from the positive pole, the difference between this proportion and that in 

 water, having been employed in producing the secondary action, from which the 

 resinous matter resulted. 



I formerly shewed that when the same electric current was passed through 

 absolute alcohol containing a small quantity of potash, iodide of potassium, or 

 chloride of calcium, and through water either containing the same proportion of 

 the same substance, or simply acidulated with sulphm-ic acid, the quantity of 

 hydi'ogen evolved at the negative pole from both solutions was the same.f I 



* It would appear that DHbereiner had observed the formation of resinous matter in small quan- 

 tities, in a galvanized solution of potash in alcohol (Pog. Annal. xxiv. 609), but he says nothing of any 

 evolution of elastic fluid at either pole ; and although he regarded the formation of resinous matter as an 

 eCfect of oxidation, he gives no more explicit opinion as to the source of the oxygen or nature of the ac- 

 tion. On the other hand, M. Ludersdorf {lb. xix. 77), like Dr Ritchie, had observed that absolute 

 alcohol, holding nothing in solution, gave o£F, under strong voltaic agency, elastic fluid from the negative 

 pole ; but he did not state that it was hydrogen, and, on the contrary, seems to have thought that it was 

 not hydrogen, from the colour of its flame. I have found that the hydrogen evolved from pyroxylic spirit 

 under electric action, when it contained a little of the vapour of the spirit mixed with it, burned with a 

 blue flame, but when freed from that vapour, by being washed with solution of potash, it burned with a 

 pale wliitish flame. In analyzing, by the voltaic eudiometer, the gases obtained in such experiments, 

 deceptive appearances, if we are not on our guard, may arise from the production of small quantities of 

 carbonic acid, proceeding from the presence of vapour of the spirit whicli has passed over. I had read 

 liuth Dobereineb's and Ludeusdohf's observations, when first published, but in the two or three inter- 

 vening years they had escaped my memory, until again recalled to it by allusions to them which I met 

 with in the course of my reading, subsequent to the publication of my former paper ; and even if I had 

 remembered them at an earlier period, they could not have superseded any part of my researches. 



t Edinb. Trans, xiii. 327, et seq. 



