ELECTRO-METALLURGY 209 



upon the subject ; considerable interest was excited in the scientific world, and much 

 astonishment among the general public by the announcement that electricity, Bunder 

 proper management, and by most easy processes, could supersede the furnace in not 

 a few operations upon metals ; and that many operations with metals, which could 

 scarcely be entertained under the old condition of things, might bo placed in the 

 hands of a child, when electricity is employed as the agent. 



Public attention was first directed to the important discovery by a notice that 

 appeared in the 'Athenaeum' of May 4, 1839, that Professor Jacobi of St. Petersburg 

 hud ' found a method of converting any line, however fine, engraved on copper, into 

 a relief, by galvanic process.' Jacobi's own account of the matter was that, while at 

 Dorpat, in February 1837, prosecuting his galvanic investigations, a striking phe- 

 nomenon presented itself, -which furnished him with perfectly novel views. Official 

 duties prevented his completing the investigation, thus opened out to him, during the 

 sumo year ; and it was not until October 5, 1838, that he communicated his dis- 

 covery, accompanied with specimens, to the Academy of Sciences at St. Petersburg ; 

 an abstract of which paper was published in the ' German News ' of the same place on 

 October 30 of the same year. And in a letter of Mr. Lettsom, dated February 6, 

 1839, the nature of the discovery is thus given in the following March number of the 

 ' Annals of Electricity.' Speaking of a recent discovery of Professor Jacobi's, he says, 

 ' He observed that the copper deposited by galvanic action on his plates of copper 

 could by certain precautions be removed from those plates in perfect sheets, which 

 presented in relief most accurately every accidental indentation on the original plate. 

 Following up this remark, he employed an engraved copper-plate for his battery, 

 caused the deposit to be formed on it, and removed it by some means or other ; he found 

 that the engraving was printed thereon in relief (like a woodcut) and sharp enough 

 to print from.' This paragraph does not appear to have caught the eye of the 

 public so readily as the briefer note that appeared a couple of months later in the 

 ' Athenaeum.' 



On May 8, or four days after the appearance of the notice in the ' Athenaeum/ Mr. 

 Thomas Spencer gave notice to the Polytechnic Society of Liverpool that he had a 

 communication to make to the society relative to the application of electricity to the 

 arts. He subsequently desired to communicate the result of his discoveries to the 

 British Association, whose meeting was at hand ; but, for some cause, which does not 

 appear, the communication was not made ; and it eventually was made public, as at 

 first proposed, through the Polytechnic Society of Liverpool, on September 12, 1839. 

 In the meantime, namely on May 22, Mr. C. J. Jordan, referring to the notice in the 

 1 Athenaeum,' wrote to the ' Mechanics' Magazine ' that, at the commencement of the 

 summer of 1838, ho had made ' some experiments with the view of obtaining im- 

 pressions from engraved copper-plates by the aid of galvanism.' His letter de- 

 scribing this process appears in the number for June 8. It occurred to him, from 

 what he had gathered from previous experience, that an impression might be ob- 

 tained from an engraved surface ; and so it was, ' for on detaching the precipitated 

 metal, the most delicate and superficial markings, from the fine particles of powder 

 used in polishing to the deeper touches of a needle or graver, exhibited their cor- 

 respondent impressions in relief with great fidelity.' 



Mr. Spencer in his communication, besides noticing the fidelity with which the 

 traces on an original plate were copied, recorded the case of a copper-plate that had 

 become covered with precipitated copper, excepting in two or three places, where by 

 accident some drops of varnish had fallen ; whence it occurred to him, and experiment 

 confirmed his conjecture, that a plate of copper might be varnished, and a design made 

 through the varnish with a point, and copper might be deposited upon the metal at 

 the exposed part, and thus a raised design be procured. 



In the ' Philosophical Magazine ' for December, 1836, Mr. De La Kue, after describing 

 a form of voltaic battery, refers to the well-known condition on which the properties 

 of the battery in question mainly depend, that ' the copper-plate is also covered with 

 a coating of metallic copper, which is continually being deposited ;' and he goes on 

 to describe that ' so perfect is the sheet of copper thus formed, that being stripped 

 out, it has the counterpart of every scratch of the plate on which it is deposited.' 

 Daniell himself, whose battery is here in question, noticed as he could not fail to 

 do in common with all who had employed his battery to any extent, the same pecu- 

 liarities ; but it does not appear that either he or De La Kue, or any one else, to whom 

 the phenomenon presented itself before Jacobi, Jordan, or Spencer, caught the idea of 

 its applicability in the arts. It would also appear that the impression came with the 

 greater vividness to the two latter ; for, while but little time seems to have been lost 

 to them in realising their idea, twenty lor-g months elapsed between the time when 

 the 4 perfectly novel views ' first presented themselves to Professor Jacobi, and the 

 time when his 'well-developed galvanic production' was communicated to the 



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