Mr. Smee's New Definition of the Voltaic Circuit. 249 



production of power, and that this latter is of no value, further 

 than as a means for the removal of the second element of the 

 intervening compound fluid. On the other hand, the mul- 

 titude of experiments by Faraday all show that the chemical 

 action between one element of a compound fluid and some 

 conducting body appears to be the source of the power, 

 or rather that the power is always directly proportionate 

 to this chemical action. Putting these two series of facts 

 together, an idea presented itself to my mind explanatory 

 of the nature of the voltaic force, for if the force from the 

 experiments of Faraday is proved to depend on chemical 

 action, and the negative pole from my own experiments is 

 proved to be useless, except as affording the means for the re- 

 moval of the second element of the compound fluid, then it 

 follows as a natural consequence, that if the chemical affinity 

 of any substance for one element of a compound fluid is 

 greater than the resistance offered to the evolution of the 

 second, force is produced. Now it immediately occurred to 

 me that some metals might be made to reduce from a solution 

 of one of their own salts, metal of the same description, by 

 placing the metal partly in a solution for one element of which 

 it has great affinity and in which it is easily dissolved, and 

 partly in a solution of one of its salts. This was actually 

 found to take place in various cases, by following the facts 

 that were made out respecting the ease with which hydrogen 

 reduces various salts. 



■ Zinc reduces zinc by taking a piece of the metal and doubling 

 it, one half is then to be amalgamated and placed in dilute 

 muriatic acid, and the unamalgamated into a strong solu- 

 tion of chloride of zinc, made as neutral as possible, when 

 the affinity of the zinc for the oxygen and the quick removal 

 of the oxide by miiriatic acid is sufficiently great to cause 

 zinc to be reduced at the other end of the same piece of metal. 

 The use of platinum, palladium, silver, copper, or any other 

 metal appears not to increase the action in the least, which 

 experiment shows most powerfully the utter fallacy of the con- 

 tact theory, or in other words, that the voltaic force is in any 

 degree dependent on the opposition of one substance to another. 

 In this experiment, according to the advocates of this now 

 untenable doctrine, the force should have set from the amal- 

 gamated zinc to the mercury, the two metals, according to 

 those electricians, having from simply looking at each other 

 the property of evolving power, — but we find that the che- 

 mical affinity determined the course of the current. 



Copper may by very simple means be made to reduce cop- 

 per with truly great rapidity ; for if a test tube be half filled 

 with sulphate of copper, and then muriatic acid be poured 



