THE 



LONDON AND EDINBURGH 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



■ — f- — 



[THIRD SERIES.] 



JUNE 1837. 



LXXX. Experiments on the peculiar Voltaic Condition of 

 Iron as excited by Peroxide of Lead ,• in a Letter to Mr. 

 Faraday. By Professor Schcenbein.* 



Dear Sir, 



I ONCE more take the liberty to address to you by writing 

 a short account of the results of* my latest researches on 

 the peculiar condition of iron. In my opinion, these results, 

 though they do not yet solve the riddle of the subject, are such 

 as to excite scientific curiosity, at least as much as the facts 

 did, a description of which I had the honour to communicate 

 to you last year. The space allotted to a letter being so small, 

 I am obliged to be as concise as possible in describing the 

 phasnomena recently observed by me ; but if you should be 

 interested with the details of the subject, I take the liberty of 

 referring you to a paper of mine which will hereafter be 

 published in Poggendorff 's Annalen. In the first place I must 

 tell you, that the most powerful voltaic association into which 

 iron can be brought in order to excite its peculiar condition, 

 is that with peroxide of lead. A common iron wire, one of 

 the ends of which is covered with this substance, proves to be 

 iaactive, not only towards nitric acid of a given strength, but 

 towards nitric acid -containing any quantity of water ; whilst, 

 as you know, my oxidized iron wire, or one associated with 

 platina, &c., is acted upon by that acid if much diluted just in 

 the same manner as unprotected iron. But the superiority 

 of the association mentioned to any other at present known is 

 exhibited in a still more striking manner by putting the two 

 endsof an iron wire (one of which is covered by peroxide of lead) 



* Communicated by Mr. Faraday. 

 Third Seties. Vol. 10. No. 65. Jutie 1837. 3 I 



