IMAGE EVALUATION 
 TEST TARGET (MT-3) 
 
 V 
 
 
 <" C^x 
 
 4 
 
 
 t^/ 
 
 / 
 
 i/x 
 
 
 1.0 
 
 I.I 
 
 '«IM 112.5 
 
 in ■? 
 
 IIM 2.2 
 
 
 IIM 
 
 2.0 
 
 .8 
 
 
 1.25 1.4 
 
 1.6 
 
 
 -4 6" — 
 
 
 ► 
 
 5^ 
 
 v] 
 
 <? 
 
 /a 
 
 ''^A 
 
 ^: 
 
 d-A 
 
 ^^ ^% 
 
 
 /. 
 
 /A 
 
 or 
 
 Photographic 
 
 Sciences 
 
 Corporation 
 
 23 WEST MAIN STREET 
 
 WEBSTER, N.Y. 14580 
 
 (716) 872-4503 
 
 m 
 
 \ 
 
 \ 
 
 ^9) 
 
 V 
 
 «r- 
 
 6^ 
 
 ^\%. <^^^ 
 
 % 
 
 V 
 
 '^V. 
 
CIHM/ICMH 
 
 Microfiche 
 
 Series. 
 
 CIHIVI/ICMH 
 Collection de 
 microfiches. 
 
 Canadian Institute for Historical Microreproductions 
 
 Institut Canadian de microreproductions historiques 
 
 1980 
 
Technical and Bibliographic Notes/Notes techniques et bibliographiques 
 
 The Institute has attempted to obtain the best 
 original copy available for filming. Features of this 
 copy which may be bibliographically unique, 
 which may alter any of the images in the 
 reproduction, or which may significantly change 
 the usual method of filming, are checked below. 
 
 L'Institut a microfilm^ le meilleur exemplaire 
 nu'il lui a 6t6 possible de se procurer. Les details 
 de cet exemplaire qui sont peut-dtre uniques du 
 point de vue bibliographique, qui peuvent modifier 
 une image reproduite, ou qui peuvent exiger une 
 modification dans la mdthode normale de filmage 
 sont indiqu6s ci-dessous. 
 
 n 
 
 Coloured covers/ 
 Couverture de couleur 
 
 Covers damaged/ 
 Couverture endommagde 
 
 D 
 
 Coloured pages/ 
 Pages de couleur 
 
 □ Pages damaged/ 
 Pages endommagdes 
 
 D 
 
 Covers restored and/or laminated/ 
 Couverture restaurde et/ou pelliculde 
 
 Cover title missing/ 
 
 Le titre de couverture manque 
 
 I I Coloured maps/ 
 
 Cartes gdographiques en couleur 
 
 ni: 
 
 Coloured ink (i.e. other than blue or black)/ 
 
 ere de couleur (i.e. autre que bleue ou noire) 
 
 ~A Pages restored and/or laminated/ 
 JIlJ Pages restaurdes et/ou pellicul^es 
 
 I — I Pages discoloured, stained or foxed/ 
 
 Pages d6color6es, tachetdes ou piquSes 
 
 Pages detached/ 
 Pages d6tach6es 
 
 r~7i Showthrough/ 
 
 Transparence 
 
 □ Coloured plates and/or illustrations/ 
 Planches et/ou illustrations en couleur 
 
 □ Bound with other material/ 
 Reli6 avec d'autres documents 
 
 □ Quality of print varies/ 
 Quality indgale de {'impression 
 
 □ Includes supplementary material/ 
 Comprend du materiel supplementaire 
 
 D 
 
 Q 
 
 Tight binding may cause shadows or distortion 
 along interior margin/ 
 
 La reliure serr^e peut causer de I'ombre ou de la 
 distortion le long de la marge int6rieure 
 
 Blank leaves added during restoration may 
 appear within the text. Whenever possible, these 
 have been omitted from filming/ 
 II se peut que certaines pages blanches ajoutdes 
 lors d'une restauration apparaissent dans le texte, 
 mais, lorsque cnia 6tait possible, ces pages n'ont 
 pas 6t6 filmdes. 
 
 n 
 
 Only edition available/ 
 Seule Edition disponible 
 
 Pages wholly or partially obscured by errata 
 slips, tissues, etc., have been refilmed to 
 ensure the best possible image/ 
 Les pages totalement ou partiellement 
 obscurcies par un feuillet d'errata, une pelure, 
 etc., ont 6t6 film6es d nouveau de fagon d 
 obtenir la meilleure image possible. 
 
 □ 
 
 Additional comments:/ 
 Commentaires suppl6mentaires; 
 
 10X 
 
 This item is filmed at the reduction ratio checked below/ 
 
 Ce document est filmd au taux de reduction indiqu^ ci-dessous. 
 
 14X 18X 22X 
 
 26X 
 
 30X 
 
 y 
 
 12X 
 
 16X 
 
 20X 
 
 24X 
 
 28X 
 
 32X 
 
8 
 
 Stalls 
 s du 
 lodifier 
 r une 
 Image 
 
 The copy filmed here has been reproduced thanks 
 to the generosity of: 
 
 Library of the Public 
 Archives of Canada 
 
 The images appearing here are the best quality 
 possible considering the condition and legibility 
 of the original copy and in keeping with the 
 filming contract specifications. 
 
 L'exemplaire film6 fut reproduit grdce d la 
 gindrositd de: 
 
 La bibliothdque des Archives 
 publiqubs du Canada 
 
 Les images suivantes ont 6t6 reproduites avec le 
 plus grand soin, compte tenu de la condition et 
 de la nettet6 de l'exemplaire filmd, et en 
 conformity avec les conditions du contrat de 
 filmage. 
 
 Original copies in printed paper covers are filmed 
 beginning with the front cover and ending on 
 the last page with a printed or illustrated impres- 
 sion, or the back cover when appropriate. All 
 other original copies are filmed beginning on the 
 first page with a printed or illustrated impres- 
 sion, and ending on the last page with a printed 
 or illustrated impression. 
 
 9S 
 
 Les exemplaires originaux dont la couverture en 
 papier est imprimde sont film^s en commen9ant 
 par le premier plat ot en terminant soit par la 
 dernidre page qui comporte une empreinte 
 d'impression ou d'illustration, soit par le second 
 plat, selon le cas. Tous les autres exemplaires 
 originaux sont f(lm6s en commenpant par la 
 premidre page qui comporte une empreinte 
 d'impression ou d'illustration et en terminant par 
 la dernidre page qui comporte une telle 
 empreinte. 
 
 The last recorded frame on each microfiche 
 shall contain the symbol ^♦^ (meaning "CON- 
 TINUED "), or the symbol V (meaning "END"), 
 whichever applies. 
 
 Un des symboles suivants apparaitra sur la 
 dernidre image de cheque microfiche, selon le 
 cas: le symbole — ^ signifie "A SUIVRE", le 
 symbole V signifie "FIN". 
 
 Maps, plates, charts, etc., may be filmed at 
 different reduction ratios. Those too large to be 
 entirely included in one exposure are filmed 
 beginning in the upper left hand corner, left to 
 right and top to bottom, as many frames as 
 required. The following diagrams illustrate the 
 method: 
 
 Les cartes, planches, tableaux, etc., peuvent dtre 
 filmds d des taux de reduction diffdrents. 
 Lorsque le document est trop grand pour dtre 
 reproduit en un seul cliche, il est filmd d partir 
 de Tangle sup6rieur gauche, de gauche d droite, 
 et de haut en bas, en prenant le nombre 
 d'images n^cessaire. Les diagrammes suivants 
 iltustrent la mdthode. 
 
 errata 
 J to 
 
 e pelure, 
 ;on d 
 
 n 
 
 1 
 
 2 
 
 3 
 
 32X 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
fPROM THE American Joor. op Sci. and Arts , Volume XLIX, March, 1870.] 
 
 Coiitrihutioiis to the Clieniistry of Copper; by T. Sterry 
 Hunt, LL.D., RRS. Part 1. 
 
 [Read before the American Associntion for the Advancement of Science at Salem, 
 « August 26, 1869] 
 
 §1. The resemblances between silver and copper in its cu- 
 prous form luive already attracted the attention of chemists. 
 The ordinary chlorid of silver (argentic cldorid) and the dichlo- 
 rid of copper (ciiproas chlorid) have many properties in com- 
 mon. Both of these chlorids are white, readily fusible, and 
 blackened by exposure to light; both of them are insoluble in 
 water but dissolve in ammonia and in aqueous solutions of 
 other chlorids, in which however the cuprous is far more solu- 
 ble than the argentic chlorid. A saturated solution of chlorid 
 of sodium holds at 90° Centigrade, 16 '9 per cent of cuprous 
 chlorid, at 40° C, 11'7, and at 11°, 8*9 per cent. A solution 
 containing fifteen per cent of chlorid of sodium retains at 90° 
 C, 10*3 })er cent of cupi-ous chlorid, at 40°, 6'0 per cent, and 
 at 14°, 3 '6 percent; vsdiile a solution with only live per cent 
 of chlorid of sodium holds of the cuprous chlorid at 90°, 2*6, 
 and at 40° only 11 per cent. These determinations are from 
 single observations and therefore require verification. From 
 the sparing solubility of the cuprous chlorid in dilute solutions 
 of chlorid of sodium it follows that the denser saturated solu- 
 tions are copiously precipitated by dilution with water, which 
 causes the separation of white cuprous chlorid in a crystalline 
 condition. 
 
 § 2. The aqueous solutions of the chlorids of calcium, mag- 
 nesium, zinc, manganese, cobalt, feiTOsum and cupricum, also 
 freely dissolve cuprous chlorid, and it is probable that this 
 property is shared by otJier soluble chlorids. The strong af- 
 finity of cuprosiim for chlorine enables cuprous oxyd to decom- 
 pose all the chlorids just named, with the exception of those of 
 sodium and calcium, with separation of the corresponding oxyds 
 and formation of cuprous chlorid. In the case of zinc and 
 manganese, insolulde oxychlorids of these metals are formed 
 at the same time. These reactions require further study, and 
 the same may be said of the cupric and cobaltic chlorids with 
 cuprous oxyd. I have, however, partially investigated the be- 
 havior of cuprous oxyd with magnesic and ferrous chlorids, 
 and obtained the results about to be described. 
 
 § 3. The cuprous oxyd for these experiments was prepared 
 by gently heating a solution of sulphate of copper mixed with 
 cane sugar and an excess of caustic soda,"''until tlie whole of the 
 copper was thrown down as a bright dense cinnabar-red powder 
 
 «•. 
 
(34) 
 
 T. S. Hunt on the Chemistry of Copper. 
 
 which was carefully washed and dried. A concentrated solu- 
 tion of chlorid of nuigncsiiini dissolves this oxyd in the cold, 
 and more readily when heated, with separation of hydrated 
 oxyd of magnesium and cuprous chlorid, which latter is held 
 in solution by the excess of magnesic chlorid. By filtering 
 the liquid while hot, and washing with a strong solution of 
 chlorid oi sodium, the hydrate of magnesia may be separated, 
 and the dissolved copper subsequently precipitated by metallic 
 iron from the colorless filtrate, ferrous chlorid being formed. 
 Experiment shows tliat the reaction between the red oxyd of 
 copper and chlorid oi' magnesium may be represented as follows : 
 Cu,0-fMgCl=Cu2CH-MgO. 
 
 §4. A solution of magnesian chlorid nearly saturated when 
 liot with cuprous oxyd, and allowed to cool in contact with the 
 precipitated mognesian hydrate, deposits a portion of orange 
 colored oxyd, or perhaps an oxychlorid, which disappears as 
 often as the sohition is heated. The solid cuprous chlorid is 
 moreover decomposed when digested with water and magnesia, 
 hydrated cuprous oxyd and magnesic chlorid being formed. 
 The double chlorid of cuprosum and magnesium is however 
 stable, even in the cold, in presence of magnesian hj^drate, pro- 
 vided a considerable excess of magnesian chlorid be present. 
 From a filtered solution of cuprous oxyd in chlorid of magne- 
 sium water precipitates a large portion of the cuprous chlorid, 
 in this case colored orange-yellow from adhering oxyd, due to 
 the reaction of a little magnesia, which remains dissolved or 
 suspended in the concentrated solution even after filtration. A 
 solution of magnesian chlorid of specific gravity 1'23, retains 
 in solution at 12° Centigrade, about 7"10 per cent of cuprous 
 chlorid. A solution of magnesian sulphate with chlorid of 
 sodium may be employed to dissolve cuprous oxyd. This, like 
 all similar solutions of cuprous chlorid, rapidly absorbs oxygen 
 from the air and deposits a pale green cupric oxychlorid. 
 
 § 5. With ferrous chlorid and cuprous oxyd it might be ex- 
 pected, from analogy with the magnesian salt, that we should 
 obtain cuprous chlorid and ferrous oxyd, but the reaction is 
 complicated by the tendency of the latter to pass to the state 
 of feme oxyd. When ferrous chlorid in solution with chlorid 
 of sodium is heated with a sufUcient quantity of cuprous oxyd, 
 the whole of the iron is precipitated as ferric oxyd, mingled 
 with metallic copper, whi'3 cuprous chlorid remains in solution. 
 Experiments made with an excess of ferrous chlorid show that 
 one third of the copper is reduced, while two thirds are dis- 
 solved as dichlorid. This reduction may be eftected directly by 
 ferrous oxyd ; if to a solution of cuprous chlorid in chlorid of 
 sodium, we add hydrated ferrous oxyd recently precipitated by 
 an alkaline base and still suspended in the liquid, it is at once 
 
T. S. Hunt on the Chemistry of Copper. 
 
 8 
 
 converted into ferric oxyd, with precipitation of metallic cop- 
 per. The first stage in the action of ferrous chlorid on cuprous 
 oxyd niav be represented as similar to that of magnesic cliforid ; 
 CujO + i'eCl^^Cu.Cl + FeO. In the second stage CuyCl + 
 3FeO=Cu ^ + FeCl + Fe, O 3 . It follows from this that one-third 
 of the cuprous chlorid formed in the first stage is reduced to 
 the metallic state, and the final result may be represented as 
 follows: 3Cu30 + 2FeCl=2Cu,Cl+2Cu-fFe303. 
 
 A similar result is obtained if ferrous chlorid is added to an 
 unfiltered solution of cuprous oxyd in chlorid of magnesium. 
 The suspended hydrate of magnesia in this case liberates an 
 equivalent of ferrous oxyd, which reduces to the metallic state 
 one-third of the dissolved cuprous chlorid, in accordance with 
 the second reaction given above. 
 
 § 6. The reducing power of ferrous oxyd is also shown with 
 cupric cblorid, which is at once converted by it into cuprous 
 chlorid in accordance with the equation, 2CuCl 4- 3FcO = 
 CUaCl-f FcCl-fFcaO,. The further action of ferrous oxyd 
 will, as we have seen, leduce the cuprous chlorid to the metallic 
 state: in fact, 2CuCl-|-6FeO = 2Cu-f 2FeCI+2Fe303. If re- 
 cently precipitated hydrated ferrous oxyd or ferrous carbonate 
 be added to a solution of cupric chlorid in the proportions indi- 
 cated by the last equation, the whole of the copper is separated 
 in the metallic state, mingled with ferric oxyd, while ferrous 
 chlorid is found in solution. The reaction with ferrous carbo- 
 nate, which requires a gentle heat, is accompanied by a violent 
 disengagement of carbonic acid gas. This experiment is best 
 made by dissolving in water feiTous sul])hate and sodic carbo- 
 nate or sodic hydrate in the proportions required, and adding 
 thereto a solution holding the proper amount of cupric chlorid. 
 Under certain conditions the cuprous preci})itate is brownish- 
 black in color, like that obtained by heating ferrous chlorid 
 with cuprous oxyd, but more generally it is of a bright red 
 color, and often coats the glass with a mirror-like film. A 
 warm solution of cupric chlorid with chlorid of sodium at once 
 conve]'ts the metallic copper of the precipitate into cuprous 
 chlorid, which is dissolved, leaving behind only hydrated ferric 
 oxyd. When a solution of ferrous chlorid with chlorid of 
 ammonium and excess of ammonia is added to a solution 
 of a cop})er salt the precipitated films of metallic copper some- 
 times possess considerable brilliancy and show a bluish ti-anslu- 
 cency. It is to be remarked that although the cupreous precipi- 
 tate thus obtained is bright red in color, that which is produced 
 by boiling cuprous oxyd with ferrous chlorid is nearly bliick. 
 
 § 7. It was long since shown by Levol that hy<lrated feirous 
 oxyd will reduce cupric to cuprous oxyd, and this, as we have 
 already seen, can separate from its combinations ferrous oxyd, 
 
4 T. S, Hunt an the Oiemtstry of Copper. 
 
 whose reducing power may be still further exerted upon the 
 cuprous combination thus formed. These facts serve to explain 
 the results obtained by E. Brann {Zeitschr. Chem., 1867, [). 568. 
 cited in Jahresberic/it for 1867), vviiicli were not known to me 
 at the time of making these experiments, lie found that by 
 digesting cupric hydrate or cupric carbonate with ferrous sub 
 phate in solution there was obtained a reddish mixture of basic, 
 ferric sid})]iate with cuprous oxyd, formed ap]>arently in accord- 
 ance with the equation, 
 
 2FeO, SO,4-2CuO=Cu,04-Fe,03, 2S0 
 
 3* 
 
 This, when boiled with a further })ortion of ferrous sulphate, 
 became black in color, and from the small amount of oxygen 
 present was supposed to contain metallic copper. By addmg a 
 large excess of carbonate of ammonia to a mixture of ferrous 
 and cupric sulphates, Braiin succeeded in obtaining solutions in 
 which all the copper was present in a cuprous form, and even 
 in reducing portions of it to the metallic state, a process which 
 we have seen is complete when tlie requisite amount of ferrous 
 oxyd is brought in contact with the chlorids of copper. 
 
 §8. In this Journal for March, 1867, page 308, I described 
 briefly the reaction between cupric oxvd and ferrous cldorid, ac- 
 cording to the equation, 3CuO-f2FCf= Fe.^0 ,+Cu,C\-\-OnG\. 
 I was not then aware that the same had been shown by Meyer 
 (Berg, und Hutt. Zeit., 1862, 182, cited by Kerl).* 'Further 
 studies of this reaction have given me interesting results. The 
 black oxyd of copper, even after ignition, is attacked by ferrous 
 chlorid in tlie cold, but the insolubility of the resulting cuprous 
 chlorid retards the action. If however the ferrous chlorid be 
 mingled with a strong solution of chlorid of sodium, and heat 
 applied, the cuprous chlorid is readily dissolved, and the reac- 
 tion is rapid and complete, the whole of the iron separating as a 
 bulky reddish-brown precipitate, provided three equivalents of 
 cupric oxyd have been taken for two of ferrous chlorid. The 
 greenish solution thus obtained readily dissolves precipitated me- 
 tallic copper, ill virtue of the cupric chlorid which it contains, 
 and, unless a large excess of chlorid of sodium be present, de- 
 posits white crystalline cuprous chlorid by cooling or by dilution. 
 When digested at a temperature of 50° Centigrade with carbon- 
 ate of lime, tlie greenish solution deposits one-third of its cop- 
 per as a pale gi-een insoluble cupric hydro-carbonate, while the 
 colorless filtrate retains the remaining two-thirds in the form of 
 cuprous chlorid. If a solution of ferrous chlorid with chlorid 
 of sodium is digested with a sufficient excess of cupric oxyd the 
 cupric chlorid formed unites with the latter to form an insoluble 
 cupric oxychlorid, and only cuprous chlorid remains in solu- 
 tion. 
 
 * Me tall. Huttenkunde, xi, 588. 
 
T. S. Hunt on the Chemistry of Copper, 5 
 
 § 9. For tlie ferrous chlorid in the experiments in §6 and §8, 
 a solution of ferrous sul})lmte with chlorid of sodium may be 
 substituted. When oupric o.xyd is heated with an excess of 
 ferrous cidorid, a small portion of ferric oxychlond is produced. 
 I he red brown precipitate may be waslied free from cupric, cu- 
 prous and ferrous chiorids by "a strong solution of chlorM of so- 
 dium, but will then yield to pure water a portion of soluble ferric 
 oxychlorid. By careful desiccation in a water-bath and subse- 
 quent washing with dilute alcohol the ferric precipitate may be 
 obtamed free from chlorid of sodium, and completely insoluble 
 in water ; but its composition appears to be variable. Of two 
 preparations the first contained one equivalent of chlorine for 
 eleven, and the second, one for twenty equivalents of iron. In 
 a,nother experiment where fine oxyd of copper from the calcina- 
 tion of malachite was dissolved inan excess of a mixture of fer- 
 rous sulphate and chlorid of sodium at a boiling heat, it was found 
 that for thirty equivalents of copper dissolv(;d there were pre- 
 cipitated twenty-one equivalents of iron, instead of twenty as 
 required by the formula given in §8; the additional equivalent 
 being separated as ferric chlorid in union with tlie ferric oxyd. 
 The production of a small and variable amount of ferric chlOrid 
 m the above conditions is apparently due to a secondary reaction 
 between cupric and ferrous chiorids in the presence of ferric 
 oxyd; 2CuCl+2FeCl = Cu,Cl4-Fe,Cl3. This point however 
 req^uires further investigation. 
 
 ^ 10. The facility with which cupric chlorid parts with one- 
 half of Its chlorine and passes into the more stable cuprous 
 compound is shown by its well known power to chloi '-ze not 
 only metallic copper, but metallic silver and even suiphid of 
 silver. Its action on cuprous suiphid is not less remarkable. 
 A strong solution of cupric chlorid mingled with chlorid of so- 
 dium rapidly attacks pulverized copper-glance, ev.-n in the cold, 
 sulphur being separated and cuprous chlorid formed; 2CuCl-f 
 CujS = 2Cu2Cl-fS. Chalcopyrite, on i\v contrary, is but 
 slightly acted upon by such a solution, which, however, slowly 
 takes up a portion of iron, forming ferrous chlorid with a corres- 
 ponding amount of cuprous chlorid. %