Mr. T. B. Jordan's Remarks on Electro-Metallurgy. 453 



in part owe. their origin to copying. If then it can be shown 

 that this method possesses advantages for some description of 

 work, which are not common to any other, and that there is 

 good reason to suppose it may be ceconomically conducted, 

 then we may fairly infer, that it will in due time become one 

 of the ordinary processes of our factories. 



Its advantages are numerous, and some of them so self- 

 evident, that they only require naming to be allowed ; for in- 

 stance, any surface, whatever be its material or form, may be 

 covered with a coating of metal, without heat and without 

 force ; this coating may be allowed to accumulate to the re- 

 quired thickness, and may then be removed from its original, 

 when the surfaces which were in contact will be found to be 

 so perfectly alike, that it is impossible to discover the minutest 

 scratch in one which has not its counterpart in the other. 

 In proof of the accuracy of the copy, I may refer to the nume- 

 rous admirable copies of engraved plates and medals already 

 before the public ; if any of these specimens be examined with 

 a glass, it will be found that not only every line of the graver, 

 but every scratch in the polished surface of the original plate is 

 faithfully transferred, both to the deposited matrix, and the 

 subsequent copy of it ; and when we consider the fact that 

 both these copies are of the same material as the original 

 plate, apd that that may just as well have been of a much soft- 

 er and more workable material, we must immediately con- 

 clude that there is no other known mode of copying pos- 

 sessing like advantages. But as the application of it to the 

 copying of engravings, medals, woodcuts, and similar subjects, 

 is already well known, I merely refer to it in illustration of 

 my views, and will now offer a few reasons for supposing 

 that it may eventually be found an ceconomical process for 

 some of the more ordinary branches of our manufactures in 

 metal. 



I can now only explain the principles which lead me to 

 imagine that it would not be a costly process on the large 

 scale. In my preliminary experiments, I have used Mr. 

 Smee's battery of platinated silver and zinc, excited by diluted 

 sulphuric acid ; it acts well, and is more convenient than the 

 sulphate of copper batteries. 



Mr. Spencer's very simple and cheap arrangements, in 

 which the negative plate of a single pair is that receiving the 

 deposit, is I think very suitable for flat work, but for compli- 

 cated forms I should certainly prefer having the battery ar- 

 rangement separate from the depositing cell, both on account 

 of its being more manageable, and because in this way the 

 solution of the sulphate of copper is kept constantly at the 



