S74 G. Th. Fechner's Justification of the 



posed to the common notions of chemistry. It now remains 

 only to determine whether this changing action of the fluid on 

 the metal is also the cause of the current. That a solution of 

 nitrate of silver really effects a change of electrical state in gold 

 and platinum, will be seen from the following circumstances : 



Gold is negative to platinum in a concentrated solution of 

 nitrate of silver ( ) part salt to 8 water) as also in a solution 

 in some degree diluted, and finally also in nitric acid saturated 

 to excess with a solution of nitrate of silver; on employing a 

 solution of nitrate of silver greatly diluted a reversion occurs 



from platinum gold into platinum gold. There are many 

 other proofs of the resulting change of the platinum to 

 positive, which I shall here however neglect. Moreover, my 

 experiments have taught me that even the noble metals are 

 capable of undergoing the most remarkable electro-chemical 

 changes in fluids which have generally been considered as 

 devoid of action upon them. It would however lead us too 

 far were we to treat on this subject at present. 



It is evident from all of the above, that with the present 

 state of science experiments on the weaker or smaller galvanic 

 activity of circuits in fluids of apparently greater or smaller 

 chemical activity cannot give certain results either favourable 

 or unfavourable to the chemical theory. The principal ob- 

 ject is to discover the cause of the peculiar changes which in 

 many cases the general condition of the metals would not 

 lead us to expect, that metals undergo in fluids, before we 

 can make use of the condition so acquired for the explanation 

 of other circumstances. 



4. The following experiment against the chemical theory 

 I made known a long time ago in Schweigger's Journal, vol. 

 Ivii. p. 9, and I should not publish it anew if it had been 

 noticed by any one of the supporters of that theory, which 

 makes me suppose that it is but little known. This experi- 

 ment, so easily repeated, and which I annually perform as a 

 class experiment, appears to me to be exactly an experimenttim 

 cnicis against the chemical theory.* 



Let an equal number of pairs of zinc and copper plates 

 (I generally employ ten) be arranged in a couronne des tasses 

 so as to form a compound circuit arranged as a pile ; so, how- 

 ever, that the one half of the elements tends to produce a cur- 

 rent opposed to that of the other. Let the conducting fluid 

 be water. If evei'ything is the same in all the cells, the two 

 opposite currents will compensate each other in action at the 

 connecting multiplier and will produce no divergence. It 



* See Prof. Schoenbein's remarks on this experiment, in p. 162. 



