60 Mr. Faraday on a peculiar Voltaic Condition of Iron. 



rent. The iron wire rendered inactive either by association 

 with the oxidized wire or in any other way, is also as platina 

 to the platina, and produces no current. 



When ordinary iron and platina in connexion by means of 

 the galvanometer are dipped into the acid, (it matters not which 

 first,) there is action at the first moment on the iron, and a 

 very strong electric current, the iron being as zinc to the pla- 

 tina. The action on the iron is, however, soon stopped by 

 the influence of the platina, and then the current instantly 

 ceases, the iron now acting as platina to the platina. If the 

 iron be lifted into the air for a moment until action recom- 

 mences on it, and be then reimmersed, it again produces a 

 current, acting as zinc to the platina ; but as before, the mo- 

 ment the action stops, the current is stopt also. 



If an active or ordinary, and an inactive or peculiar iron 

 wire be both immersed in the nitric acid sepai'ately, and then 

 connected either directly or through the galvanometer, the se- 

 cond does not render the first inactive, but is itself thrown into 

 action by it. At the first moment of contact, however, a strong 

 electric current is formed, the first iron acting as zinc, and the 

 second as platina. Immediately that the chemical action is 

 reestablished at the second as well as the first, all current 

 ceases, and both pieces act like zinc. On touching either of 

 them in the acid with a piece of platina, both are protected, 

 and cease to act ; but there is no current through the galva- 

 nometer, for both change together. 



When iron was associated with gold or charcoal, the phae- 

 nomena were the same. Using steel instead of iron, like ef- 

 fects ensued. 



One of the most valuable results in the present state of this 

 branch of science which these experiments afford, is the addi- 

 tional proof that voltaic electricity is due to chemical action.^ and 

 not to contact. The proof is equally striking and decisive with 

 that which I was able to give in the Eighth Series of my Ex- 

 perimental Researches (par. 880)*. What indeed can show 

 more evidently that the current of electricity is due to chemi- 

 cal action rather than to contact, than the fact, that though 

 the contact is continued, yet when the chemical action ceases, 

 the current ceases also ? 



It might at first be supposed, that in consequence of the 

 peculiar state of the iron, there was some obstacle, not merely 

 to xhe. formation of a current, but to the passage of one; and 

 that, therefore, the current which metaUic contact tended to 

 produce could not circulate in the system. This supposition 

 was, however, negatived by removing the platina wire into a 

 * See Lond. and Edinb. Pliil. Mag., vol. vi. p. 36.— Edit. 



