Mr. Smee on the Galvanic Properties of Metals. 315 



cases where organic matters are replaced by pyrites, but also 

 in those where silica and other earthy substances are con- 

 cerned. 



By this process I was easily enabled to cover the surface 

 of any article moulded in plaster, sulphur, wax, or any other 

 substance; but it usually happened that by the time that the 

 whole surface was covered some parts had begun to throw up 

 little mammillated excrescences of copper which destroyed 

 the smoothness and regular appearance of the surface. Al- 

 though I thus failed in my original purpose, yet I saw sufficient 

 reason to feel no doubt that plaster may be covered with a 

 uniform coating of copper. The surface of the copper preci- 

 pitated against the plaster is of course smooth, and there- 

 fore the process might be conveniently employed in any case 

 where one or only a few copies are required of any metallic 

 surface. Thus finger plates for doors, and all kinds of thin 

 ornamental metal work, may be copied with great perfection. 



A verj'^ beautiful effect is produced by coating the sur- 

 face of facsimiles of medals or casts, made of lead or fusible 

 metal, with a thin film of reduced copper ; they then exhibit 

 the beautiful silky dull appearance which I have before al- 

 luded to as being possessed by the precipitated metal. If 

 these could be preserved from tarnishing by the application 

 of any varnish or lacquer, exceedingly beautiful and cheap 

 ornaments might be made in this manner, such as clock 

 cases, &c. 



I have likewise been engaged in a series of experiments on 

 the precipitation of other metals by similar means, and shall 

 probably, when sufficiently at leisure, prepare a short account 

 of them. 



38, Bedford Row, March 2, 1840. 



LIII. On the Galvanic Properties of the Metallic Elementary 

 Bodies^ "doith a description of a new Chemico-Mechanical 

 Battery. By Alfred Smee, Esq.* 



T AST May a number of experiments were performed upon 

 ■'-^ the galvanic properties of the non-metallic elementary 

 bodies, and these were attended with the acquisition of some 

 curious information fj but till lately no opportunity has pre- 

 sented itself of extending the series of investigations then con- 

 ducted : now, however, that I believe that I can lay before 



* Communicated by the Author. 



t The results connected v/ith this part of the subject will be given in a 

 future number. 



