586 Transactioyis. — Chemistry. 



The interpolar connection between the two vessels contain- 

 ing the acid and alkaline solutions was a third vessel charged 

 with a strong solution of salt, from which solution two pieces, 

 of filter-paper rose on either side, and, one entering the acid 

 and the other the alkali, the connection was thus completed. 

 The object of interposing the saline solution was to escape the 

 interference of those electric currents that Faraday discovered 

 to be generated by the combination of acids with alkalies. 



These results (Nos. 4 and 5) demonstrate the fact that the 

 affinity of iron for oxygen in alkaline solutions is even greater 

 under these circumstances than its affinity for this substanc'e 

 in acid solutions, in which solutions, as we know, it is rapidly 

 attacked and dissolved ; and by so much they further demon- 

 strate the fact that not only is a negative metal unnecessary 

 to initiate the oxidizement of the iron, but that the tendency 

 to oxidize on the part of this metal in alkaline solutions is so 

 great that it can be very heavily handicapped without being 

 overpowered. 



It should be stated here that, generally, the stronger the 

 acid used in these experiments — the greater their action on 

 the iron — the more electro-positive the iron in the potash is. 



6. The best iron wire that I can obtain, when allowed tO' 

 have contact with an alkaline solution for a considerable time, 

 may be seen to have acquired a darkish colour when it is com- 

 pared side by side with a piece of the same wire that has not 

 been thus immersed, showing that the metal is oxidized as 

 unassisted by coupling it with another metal. 



These results, taken as a whole, show very plainly that 

 iron, like gold, platina, and silver, readily oxidizes in alkaline 

 or strongly saline solutions in which it has hitherto been sup- 

 posed to be unaffected ; and they show besides that carbonic 

 acid is not, as Professor Grace Calvert has stated, necessary 

 for this action. In either of these solutions, in fact, it rapidly 

 enfilms, but the film being insoluble therein, the process soon 

 ceases, therefore the bulk of the iron is preserved, while the 

 action may easily remain undetected. However, when the 

 iron is polarised, either by itself or another metal, this oxida- 

 tion goes on faster, and the evidences of it are quickly mani- 

 fested. 



Thus all the metals are alike in this — that each oxidizes 

 in air and water ; the only difference being as to the degree of 

 the intensity of their affinities for oxygen under these circum- 

 stances, some, as iron and zinc, being able to decompose water 

 to satisfy their affinities, while others, such as platina, gold,, 

 and silver, are unable to do this, so take all their oxygen from 

 the air present in the solution surrounding them. 



It will also be seen that, so far as these statements are 

 accurate, they are favourable to the opinion I expressed over 



