64 ELECTROTYPE PROCESSES. 



distilled water, and then immersed in the solution of protochloride 

 of gold about three minutes : the surface takes a bronze tinge by 

 the reduction of the gold. It is next washed in distilled water by 

 merely dipping, not by throwing water upon it. The wire connec- 

 tion is now attached to the zinc of the battery, and then the article 

 put into the copper solution, and in a few minutes the article is 

 coated over with a deposit of copper. A thin copper surface may 

 thus be given to small busts or figures without sensibly distorting 

 the features by want of proportion. 



Figures from Elastic iTionida. When taking a wax cast from the 

 elastic mould, described in page 58, we prefer the phosphorized 

 mixture. After taking out the mould it is only necessary to make 

 the connections, and pass it through the gold and silver solutions, as 

 described, and then to connect it with the battery. 



We may also mention that the principal object of making copper 

 moulds by this process, in the Manufactory, is not to make fac-similes 

 in copper, but to make articles of solid silver or gold. Copies of 

 highly wrought work, either chased or engraved, or of articles, du- 

 plicates of which cannot be obtained, or of which the workmanship 

 is costly, may by this means be made in solid silver or gold, at little 

 more expense than the cost of the metal. Having obtained the 

 copper mould, silver is deposited in it to any thickness, and the 

 copper dissolved off. However, an extensive trade is now being 

 carried on in figures and other works of art deposited in copper and 

 then bronzed, which gives them an appearance often not much 

 inferior to that of antique works of the highest art. 



Electrotypes from Daguerreotypes. What may be justly termed 

 the perfection of electrotyping, is the production of electrotypes 

 from daguerreotypes. The daguerreotype picture being taken, a 

 small portion of the back is cleaned with sand-paper, taking care 

 not to allow anything to touch the face ; a little fine solder is placed 

 on this part ; a piece of flattened wire, also cleaned, is placed upon 

 the solder, the whole moistened with dilute muriatic acid, or chloride 

 of zinc. The wire is now held over the gas or a lamp about half an 

 inch from the plate ; the heat is transmitted through the wire to the 

 solder, which melts, and the wire is soldered to the type ; the back 

 is then protected by wax, and the daguerreotype is now put into 

 the copper solution in the same manner as a medal ; the deposit 

 proceeds rapidly, and when sufficiently thick the two easily separate, 

 and an impression of the picture is obtained from the daguerreo- 

 type, with an expression softer and finer than the original : several 

 electrotypes may, with care, be taken from one picture. The 

 electrotype may now be passed through a weak solution of cyanide 

 of gold and potassium, in connection with a small battery, and thus 

 a beautiful golden tint be given to the picture, which serves to 



