UNDULATORY FORCES.-ELECTRO-METALLURGY. [COPPKB BOLUTIOX* 



cyanogen gn* i evolved, which, if freely inhaled, i 

 dangerous to the health : in consequence, also, of this 

 pe of cyanogen, Uio cyanide of ooppor is not a 



jiroto-cymuido, but contains two equivalents of cyanogen 

 for every three equivalents of copper ; it i freely soluble 

 in a solution of cyanide of potassium ; it is also soluble 

 in aqueous ammonia and in a solution of carbonate of 

 ammonia. The proportions of materials we have used in 

 making it, hare been 65 part* of cyanide of potassium. 

 and 135 parts of aulphate of copper. The precipitating 

 solution is invariably greenish-blue, and contains much 

 dissolved copper after all precipitation ceases ; but no use 

 has hitherto boon made of this remainder. 



120. Copper Kolutitmt, Copper may be easily depo- 

 sited either by simple iinmorston (wash process), by the 

 single cell, or by the battery process. According to 



-oh, iron may be coated with a durable and polish- 

 able layer of copper of any thickness (?). The process 

 by simple immersion is thus : Mix together one mea- 

 sure of hydrochloric acid, three measures of water, and 

 a few drops of a solution of sulphate of copper ; clean 

 and immerse the iron ; wash it, rub it with the copper 

 solution, and reimmerse it repeatedly, adding a tew 

 drops of the copper solution occasionally. In depositing 

 copper by the single cell process, a nearly saturated solu- 

 tion of sulphate of copper answers very well ; but for the 

 battery process, an excellent solution may be made by 

 dissolving four parts, by weight, of finely divided sul- 

 phate of copper (best quality), and one part of sulphuric 

 acid, in about eighteen or twenty parts of water, and 

 then filtering it; neither of these solutions, however, is 

 fit to deposit copper upon iron, steel, or zinc ; because 

 the electrical relations of these metals in the solution 

 are unsuitable: these metals decompose the solutions 

 rapidly, and deposit the copper upon themselves by 

 simple immersion. To effect an adhesive deposit of 

 copper upon iron, a solution composed of cyanide of 

 copper dissolved in a solution of cyanide of potassium 

 may be used. It is formed thus : Dissolve cyanide of 

 copper to saturation in water containing about two 

 pounds of cyanide of potassium to the gallon, and then 

 add about one-eighth more of the cyanide of potassium 

 solution to form free cyanide ; the liquid is then ready, 

 and should be used at a temperature of about 150 Fall. 



121. Copper is electro-positive to irou in the follow- 

 ing liquids at 00 Fah. : Powerfully in a solution of 

 liv.lrosulphurot of ammonia; feebly in a saturated solu- 

 tion of ammonia ; in a solution of oxide of copper in 

 liquid ammonia ; in aqueous ammonia, or in a saturated 

 solution of ferro-cyanido of potassium, each but for a 

 short time; it then becomes negative. In a saturated 

 solution of bichromate of potash ; in a strong aqueous 

 solution of sulphide of potassium, it is increasingly 

 positive up to the boiling point of the liquid. This last 

 liquid has a similar effect on brass. 



r_"J. Bratting Solutions. Much interest and impor- 

 tance was long attached to the discovery of solutions 

 whereby alloys, and especially brass, might bo deposited 

 in the regiiiiuo state, and various liquids have been 

 used and patented for this purpose. M. de Ruolz, in 

 1841, deposited brass from the cyanides of zinc and 

 copper, dissolved together in a solution of cyanide of 

 potassium. Copper articles may be superficially brassed 

 by boiling them in a solution of hitartrato of potash 

 with zinc amalgam, or by boiling them in dilute hyilro- 

 chlnric acid with some bitartrato of potash and zinc 

 amalgam. 



I 'J.l. The same object was effected by Russell and 

 rich's patent, dated March 19th, 1840 ; which is as 

 follows : Take 10 pounds of acetate of copper, 1 pound 

 of acetate of zinc, 10 pounds of acetate of potash, and 5 

 gallons of hot water; dissolve the salts in the water, add 

 as much of a solution of cyanide of potassium as will 

 precipitate the mixture, and redissolve the precipitate ; 

 in addition, add almnt one-tenth of cyanide of potassium. 

 Use a brass anode, or else two anodes one of zinc and 

 one of copper. 



124. Joseph Rtoole's patent, dated August Oth, I860. 

 Dissolve 2} pounds of American potash in 6 gallons of 



hot water, and filter the solution ; also dissolve ty onnccc 

 of acetate of copjx-r in half a pint <i 1 am- 



monia, and add it to the first solution wit: . also 



add 4 or 6 ounces of sulphate of zinc, and stir till dis- 

 solved ; and, finally, add 2 ounces of cyanide of potas- 

 sium, iilt<-r the resulting solution, and use it at 100* 

 Fah., with a brass anode. To obtain a dark-coloured 

 brass add more acetate of copper ; and to obtain it of a 

 lighter colour, add more sulphate of zinc. 



125. Saliedc's patent, dated September 30th, 1847 

 Take 6,000 parts of water, dissolve 12 parts of cyanide 

 of potassium in 120 parts of it, then add 610 parts of 

 sub-carbonate of potash, 48 parts of sulphate of zinc, 

 and 25 parts of chloride of copper to the remainder of 

 the water, and heat the mixture from 144 to 172 Fah. ; 

 and when the salts are entirely dissolved, add 306 parts 

 of nitrate of ammonia, allow the liquid to remain un- 

 disturbed for twenty hours, and then add the solution 

 of cyanide of potassium ; allow it to remain again till 

 clear, and then draw off the transparent liquid, whi-h 

 is ready for use; work it with a large brass anode and n 

 strong battery. Another liquid which he uses for brass- 

 ing, consists of 5,000 parts of water, 500 parts of sub- 

 carbonate of potash, 35 parts of sulphate of zinc, 15 parts 

 of chloride of copper, and 50 parts of cyanide of potas- 

 sium. For a bronzing solution, he uses 25 parts of 

 chloride of tin in place of the sulphate of zinc of the 

 first brassing liquid, and proceeds as with that process ; 

 for A second bronzing solution, ho uses 12 parts of 

 chloride of tin in place of the sulphate of zinc of the 

 second brassing liquid, using the solution from 77 to 

 97 Fuh. 



12C. Brunei, Bisson, and Gaugain's formula consists 

 of 50 parts of carbonate of potash, 2 parts of chloride of 

 copper, 4 parts of sulphate of zinc, and 25 parts of 

 nitrate of ammonia, dissolved together in cold 

 which are used with a brass anode and a strong battery. 



127. Morris and Johnson's patent, dated December 

 llth, 1852. According to this patent, dissolve 1 pound 

 of cyanide of potassium, 1 pound of commercial car- 

 bonate of ammonia, 2 ounces of cyanide of copper, and 

 1 ounce of cyanide of zinc, in 1 gallon of water, and use 

 the solution at 150 Fah., with a large anode of brass 

 and a powerful battery. Or a solution may l>e tak. 



1 pound of cyanide of potassium and 1 pound of car- 

 bonate of ammonia, dissolved in 1 gallon of water, and 

 saturated with copper and zinc to the requisite <|. 

 by means of a strong battery, a large brass anode, and 

 small cathode, until the latter receives a good deposit of 

 brass ; the solution being at a temperature of 150 Fah. 

 To increase the proportion of copper in the, <lri 

 either add cyanide of potassium, or raise the temporal HIT 

 of the liquid ; and to increase the proportion of zinc 

 in it, either add carbonate of ammonia, or lower the 

 temperature. 



128. Of the numerous solutions that have been tried 

 for depositing brass, the one just mentioned is iniu-h flu- 

 best. By it, rogulino and thick deposits of brass, of 

 uniform colour, and of any desired composition, may be 

 obtained. It is not an expensive liquid; it acts with 

 average strength upon the anode ; it holds a sulli< 

 quantity of the alloy in solution ; it conducts electricity 

 with moderate facility; and it yields its metal in the. 



nio state very uniformly; it bean a great variation 

 in the, electric power without injury to the character of 

 the deposit, and is, therefore, very easily managed ; it 

 does not act perceptibly upon cast-iron, wrouuht-ii.'ii. 

 steel, or even zinc, so as to injure the adhesion of the 

 deposit; and it is not decomposed by exposure to the 

 atmosphere, to light, or heat, in such a way as to affect 

 its depositing power. Its defects are, that it requires 

 to be worked hot, and with considerable battery power, 

 in order to make the anode dissolve rapidly, the solution 

 conduct copiously, and to cause a rapid deposit ; it also 

 evolves an abundance of gas at the cathode when work- 

 ing, whether the solution bo hot or cold, which indicates 

 that part of the battery power is expended in decom- 

 posing the water of the liquid, debiting its hydrogen 

 with the metallic alloy, and oxidising the solution. 



