Electrogro,phy. 157 



Art. XIX. — Electrography or the Electrotype.* 



Instructio7is for the Multiplication of Works of Art in Metal 

 hy Voltaic Electricity ; by Thomas Spencer. (Part IV of 

 Griffin's Scientific Miscellany: Glasgow, 1840, pp. 62.) 



It is now about three years since we were first informed in the 

 public prints, that Prof. Jacobi, of St. Petersburg, had succeeded 

 in producing lines of metallic copper in relief, upon plates of the 

 same metal, by precipitation from the solutions of the sulphate of 

 that metal, by aid of Voltaic electricity. 



Since that time very many experiments have been instituted 

 on the subject, all having the same object in view, viz. the pro- 

 duction of perfect metallic casts or copies of medals, copper-plates, 

 and other works of art. But no one has attained the object more 

 perfectly or by more simple means than Mr. Spencer, of Liverpool, 

 whose attention was called to this subject before any thing was 

 known by him of what Prof. Jacobi had done. We do not pre- 

 tend to give an opinion as to the priority of claim which either 

 of these gentlemen may have to the process in question, since we 

 deem it quite possible that each may have pursued his own re- 

 searches, both leading to the same result, without any knowledge 

 of what was doing by the other ; and without the slightest inten- 

 tion of interference.! 



The conditions necessary to the success of this process are the 

 following. 1. Two fluids, one of which must be a saturated so- 

 lution of the salt, on the negative side of a Voltaic series ; the oth- 

 er may be, either water slightly acidulated with sulphuric acid, 

 or a weak saline solution, as sulphate of soda. 



2. These two fluids must he in conta.ct without mixture; this 

 is effected by placing them in a vessel provided with a porous di- 

 vision, such as plaster of Paris, unglazed earthen ware, brown 

 paper, bladder, calf-skin, or other animal membrane. 



* Some of our readers may have been surprised, that we have not sooner given 

 an account of this important art. We should have done so, but preferred to wait 

 until we had time to go through ourselves with the process in all its details. We 

 were reminded of our backwardness by receiving, through the kindness of the 

 author, the work whose title stands at the head of this article, and have revised 

 our experiments made many months since on this subject, and instituted others. 

 Our experience will be found in the above notice of Mr. Spencer's pamphlet. 



t In a Liverpool paper, we find an ardent vindication of Mr. Spencer's claim to 

 priority and superior excellence in the results. 



