54) Prof. Schoenbein on a j^eculiar Voltaic Condition of Iron^ 



But by far the most curious fact observed by me is, that 

 any number of iron wires may be made indifferent to nitric 

 acid by the following means. An iron wire with one of its 

 ends oxidized is made to touch another common iron wire ; 

 both are then inti'oduced into nitric acid of sp. gr. 1*35, so 

 as to immerse the oxidized end of the one wire first into 

 the fluid, and to have part of both wires above the level of 

 the acid. Under these circumstances no chemical action upon 

 the wires will take place, for the second wire is, of course, but 

 a continuation of that provided with an oxidized end. But 

 no action occurs, even after the wires have been separated 

 from each other. If the second wire having become indif- 

 ferent be now taken out of the acid and made to touch at any 

 of its parts not having been immersed a third wire, and both 

 again introduced into the acid so as to make that part of the 

 second wire which had previously been in the fluid enter first, 

 either of the wires will be acted upon either during their 

 contact or after their separation. In this manner the third 

 wire can make indifferent or passive a fourth one, and so on. 



Another fact, which has as yet, as far as I know, not been 

 observed, is the following one. A wire made indifferent by 

 any of the means before mentioned is immersed in nitric acid 

 of sp. gr. 1-35, so as to have a considerable part of it remaining 

 out of the fluid ; another common wire is put into the same 

 acid, likewise having one of its ends rising above the level of 

 the fluid. The part immersed of this wire will, of course, be 

 acted upon in a lively manner. If the ends of the wires which 

 are out of the acid be now made to touch one another, the 

 indifferent wire will instantly be turned into an active one, 

 whatever may be the lengths of the parts of the wires not im- 

 mersed. (If there is any instance of chemical affinity being 

 transmitted in the form of a current by means of conducting 

 bodies, I think the fact just stated may be considered as such.) 

 It is a matter of course that direct contact between the two 

 wires in question is not an indispensably necessary condition 

 for communicating chemical activity from the active wire to 

 the passive one ; for any metal connecting the two ends of 

 the wires renders the same service. 



Before passing to another subject, I must mention a fact, 

 which seems to be one of some importance. An iron wire 

 curved into a fork is made to touch at its bend, a wire pro- 

 vided with an oxidized end; in this state of contact both are 

 introduced into nitric acid of sp. gr. 1-35 and 30°, so as 

 first to immerse in the acid the oxidized end ; the fork will, 

 of course, not be affected. If now a common iron wire be 

 put into the acid, and one of the ends of the fork touched by 

 it, this end will immediately be acted upon, whilst the other 



