4 HISTORY OP ELECTRO-METALLURGY. 



in thus noticing the observations of the first pioneers in electro- 

 chemistry, because these and similar facts of later date have been 

 brought prominently forward by writers upon electro-metallurgy, 

 with the apparent intention to detract from the merit due to the dis- 

 coverers of the new art; founding their objection on the ground 

 that the principle upon which the discovery is founded is not new. 

 "Electro-metallurgy," says Mr. SMEE, "may be said to have its 

 origin in the discovery of the constant battery by Professor DAISIELL, 

 for in that instrument the copper is continually reduced upon the 

 negative plate." And again, when speaking of Daniell's battery, he 

 says Mr. M. DE LA RUE experimented on its properties, and found 

 the copper plate also covered with a coating of metallic copper, which 

 is continually being deposited ; and so perfect is the sheet of copper 

 thus formed, that being stripped off, it has the counterparts of every 

 scratch of the plate on which it is deposited." 1 



Doubtless these experiments border very closely upon the dis- 

 covery ; but yet they have no more claim to serve as dates to its 

 origin, than those we have been referring to. But if it be necessary 

 that an originating experiment must have a resemblance to that 

 which it suggests such as Daniell's battery, and the single cell of 

 electro-metallurgy why omit to refer to Dr. Wollaston's earlier 

 experiments of 1801 ? He says " If a piece of silver, in connection 

 with a more positive metal, be put into a solution of copper, the 

 silver is coated over with the copper, which coating will stand the 

 operation of burnishing." 2 But in our opinion none of these results 

 originated electro-metallurgy : the discovery of that art, although it 

 is an application of such results as we have described, was as original 

 on the part of the discoverers, and as unconnected with these results 

 at the time it was made, as it would have been had the earlier obser- 

 vations never been published. The discovery seems to have been 

 deduced from results which the discoverers had obtained in their 

 own experiments, not even while searching for such a discovery, but 

 during investigations instituted for other purposes. 



Use of Observed Facts. It must not be supposed that we depre- 

 ciate the value of the published facts upon the decomposition of salts, 

 nor that we overlook their relation to the discovery which followed ; 

 for the multiplication of facts, and the improvement of instruments 

 for experimenting, enlarge our knowledge of the principles to be 

 investigated or applied: they facilitate inquiry, and increase the 

 number of observers. The circumstances connected with the dis- 

 covery of ELECTRO-METALLURGY of the application of the decom- 

 posing force of an electro current passing through a solution, will 

 illustrate these observations. 



1 Smee, Elements of Electro-Metallurgy. 2nd Edition, 184,3. 



2 Philosophical Transactions, 1801. 



