oo 



UNDDLATOKY FORCES.-ELECTRO-METALLURGY. [LAWS OF DBPO*. 



copper, biimuth, sine, tin, load, and iron receive a cop^r 

 -it ; whilst antimony, uiokel, ooppor, silver, gold, 

 ant I platina do not 



!- r. In a solution of nitrate of copper, 

 7 ; .ii'-. tin, Ic.id, ami iron become coated ; whilst antimony, 

 ith, nickel, copper, silver, gold, and platina n 

 pout. 



Murvle of Copper. With a solution of diehloride 



of copper in liquid ammonia, or of oxido of copper in a 



: sal-ammooiao, zinc receives a deposit ; whilst 



antimony, bismuth, tin, lead, iron, nickel, ooppor, silver, 



gold, or p'atiii.i ilo not. 



i!ts. Solutions of mercurial salts nave 

 metal deposited by arsenic, antimony, bismuth, 

 admimn, tin, load, iron, copper, and brass ; also by 

 the alloys of silver with zinc, tin, lead, or copper. 



rate of Mercury. A solution of nitrate of mercury 

 yields its metal to bismuth, zinc, cadmium, lead, iron, or 

 copper, and, if acidulated with nitric acid, to antimony 

 also ; but not to silver, gold, or platina. 



Acetate of Mercury. Iron deposits mercury from a 

 solution of acetate of mercury. 



Silver Solutions. The following metals viz., man- 

 ganese, arsenic, antimony, bismuth, zinc, cadmium, 

 tiu, lead, iron, copper, and mercury, deposit silver from 

 its solutions in the metallic state ; an aqueous solution 

 of nitrate of silver yields its metal to manganese, 

 arsenic, antimony, bismuth, zinc, tin, lead, iron, nickel, 

 copper, brass, and German silver ; but not to silver, 

 gold, or platina. Lead and tin deposit the silver most 

 quickly ; then follow the other metals in this order 

 uitim, zinc, copper, bismuth, antimony, arsenic, 

 mercury. Arsenic deposits silver from the alcoholic 

 solution of nitrate of silver ; antimony receives a coating 

 of silver either in the aqueous sulphate 'or alcoholic 

 nitrate. ; bismuth deposits silver from the alcoholic ni- 

 trate, but not from the aqueous sulphate; zinc rer 

 a silver deposit in the alcoholic nitrate ; tin becomes sil- 

 vered in the alcoholic nitrate, but more quickly in the 

 aqueous sulphate; iron deposits silver from the sulj 

 of silver, but not from the alcoholic nitrate ; copper de- 

 posits it from the aqueous sulphate or alcoholic nitrate ; 

 brass and the alloys of silver, with zinc, tin, or lead, 

 deposit silver from silver solutions completely. In a 

 solution of the double cyanide of silver and potassium 

 (tho ordinary plating liquid), zinc, lead, and copper be- 

 come silvered ; also brass and German silver, but more 

 slowly; whilst antimony, bismuth, tin, iron, nickel, 

 silver, gold, and platina do not. 



Quid Solutions. From an acid solution of terchlorido 

 of gold, most of the base metals, likewise mercury, 

 silver, platina, and palladium deposit gold, generally in 

 the metallic state, but not always ; arsenic rapidly de- 

 posits gold from this solution ; antimony, tellurium, and 

 bismuth become gilded; zinc, cadmium, load, iron, 

 .it, mercury, silver, platina, and palladium deposit 

 the gold; whilst titanium, tungsten, molybdenum, and 

 chromium do not. In a solution of the double cyanide, 

 of gold and potassium, zinc quickly becomes gilded, ami 

 copper, brass, and German silver slowly; whilst anti- 

 mony, bismuth, tin, lead, iron, nickel, silver, gold, and 

 platina do not. 



Bichloride of Platina. Platina is deposited from a 

 solution of iU bichloride by arsenic, antimony, tellurium, 

 bismuth, zinc, cadmium, tin, lead, iron, cobalt, nickel, 

 copper, brass, German silver, mercury, and silver; but 

 not by gold or platina. 



5. Observations upon Class of Instances, No. 1. In 

 reviewing all these instances, we may make the following 

 observations : 1st, that various metals, by mere im- 

 mersion in solutions of other metals, at the ordinary 

 temperature of the atmosphere, sometimes become 

 coated with a deposit of metal, and sometimes not ; 

 2nd, that no metal becomes coated by mere imm 

 in a solution of tho same metal for instance, zinc does 

 not become coated with zinc in a solution of sulphate of 

 zinc; copper v. . in a solution of its sul; 



gold with gold in its chloride ; I'.nl, that the baser 

 inetaU, especially zinc, cadmium, tin, lead, and iron, 



become coated nioru frequent: noble metals, 



especially gold and pl.itm.i; ith, that solutions of base 

 metals, especially of zinc and iron, yield their metal leaa 

 frequently thin those of tho nolilu metals, especially 

 those of gold and platina; 5th, that of all tho ordinary 

 metaU mentioned in the foregoing instances, zinc de- 

 posits metal from the greatest number of solutions, and 

 appears to have the strongest depositing power ; 6th, 

 that tho coherent and adhesive deposits obtained, ai 

 all cases, exceedingly thin; and 7th, that frequently the 

 deposited metal, whatever its kind may bo, has the ap- 

 pearance of a black or dark -coloured powder on its sur- 

 face, especially when it has been deposited very rapidly ; 

 but sometimes it exhibits its ordinary colour and appear- 

 ance, especially if its outer portion be ruiii.ed oil'. 



G. To this mode of depositing belongs the process of 

 tinning brass articles (wash tinning), by Ixjiling them in 

 water containing a salt of tin and bitartrate of potash ; 

 the process of silvering brass nails, buttons, hooks and 

 eyes, buckles,' <tc., by rubbing them with any of the 

 well-known silvering compositions moistened with water ; 

 also the water-gilding process, jfeo. 



7. Depositing Arrangement No. 2. Deposition by Two 

 < ami One Lu[itvl. Tho following instances belong 

 to the class of deposition by two metals and one. liquid, 

 the two metals being either in mutual contact (touching 

 each other either above or beneath tho liquid), or 

 nected together by a wire. 



Fig. so. Chloride of Antimony. If we immerse 



a piece of antimony A, in contact with a 

 piece of zinc B, in a solution of the 

 ordinary chloride of antimony C, it will 

 receive a coating of antimony ; or if we 

 immerse a piece of platina in contact with 

 a piece of tin in this liquid, it will receive 

 a deposit of antimony; but if we ium 

 a piece of antimony in contact with a 

 piece of platina, or a piece of platina in 

 contact with a piece of silver in this liquid, it will receive 

 no metallic deposit. 



Chloride of Bismuth. In a solution of chloride of 

 bismuth, brass in contact with a piece of zinc, copper in 

 contact with tin, or German silver with iron, receive .1 

 deposit of bismuth ; but brass in contact with a piece of 

 gold, gold in contact with silver, or German silver with 

 platina, receive no deposit. 



Sulphate, Chloride, or Nitrate of Zinc. With a solu- 

 tion of either sulpliato, chloride, or nitrate of zinc, no 

 metal of any pair of metals selected from amongst the 

 following, will receive a deposit of zinc : antimony, bis- 

 muth, zinc, tin, lead, iron, nickel, copper, mercury, 

 silver, gold, platina, or palladium. 



Protocltiortde of Tin. With a solution of protochloride 

 of tin, either antimony, tin, or copper, immersed in 

 contact with zinc or lead, will receive a coating of tin ; 

 but antimony in contact with tin, tin with silver, copper 

 with iron, or either gold or platina with copper, will not 



a deposit. 



H yponitrite of Lead. With a solution of hyponitrite 

 of lead, either tin, copper, or brass, in contact with a 

 piece of zinc, will receive a deposit of lead; but tin in 

 contact with copper, copper with lead, or brass with 

 plat.ina, receive no deposit. 



Nitrate of Lead. With a solution of nitrate of lead, 

 either copper, brass, or silver, in contact with zinc, 

 receive a coating of lead ; but copper in contact with 

 iron, brass with tin, or silver with copper, receive no 

 such coating. 



Proh>snli>hate, of Iron. With a saturated solution of 

 protosulphate of iron, platina in contact with zinc re- 

 ceives a deposit of iron ; but in contact with copper it 

 receives no metallic deposit, 



Chloride of Nickel awl Ammonia, In a solution of the 

 double chloride of nickel and ammonia, copper in cor 

 with /.iin 1 . receives a deposit of nickel; but in contact 

 with .silver it doe* not receive such a deposit. 



Xiil/ihiitf i if t'o/i/u'r. In a solution of sulphate of 

 copper, brass in contact with zinc; or tin, German 

 silver, silver, or platina, in contact with iron, receive 



