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ELECTROTYPE MANIPULATION. 
 
 BEING 
 
 THE THEORY AND PLAIN INSTRUCTIONS 
 
 IN THE ART OF 
 
 WORKING IN METALS, 
 
 BY 
 
 PRECIPITATING THEM FROM THEIR SOLUTIONS, 
 THROUGH THE AGENCY OF 
 
 GALVANIC OR VOLTAIC ELECTRICITY. 
 
 ALSO IN THE ARTS OF 
 
 ELECTRO-PLATING, ELECTRO-GILDING, AND ELECTRO-ETCHING; 
 
 WITH AN 
 
 ACCOUNT OF THE MODE OF DEPOSITING METALLIC OXIDES, AND OF 
 THE SEVERAL APPLICATIONS OF ELECTROTYPE IN THE ARTS, 
 
 BY 
 
 CHARLES V. WALKER, 
 
 HONORARY SECRETARY TO THE LONDON ELECTRICAL SOCIETY; EDITOR OF 
 THE ELECTRICAL MAGAZINE, KTEMTZ'S METEOROLOGY, ETC. 
 TELEGRAPH ENGINEER, AND SUPERINTENDENT TO THE SOUTH-EASTERN 
 RAILWAY COMPANY. 
 
 ILLUSTRATED BY WOOD-CUTS. 
 
 SECOND AMERICAN, 
 FROM THE TWENTY-FIFTH ENGLISH EDITION. 
 
 PHILADELPHIA: 
 HENRY CAREY EAIRD, 
 
 SUCCESSOR TO E. L. CAREY. 
 
 1852. 
 
GETTY CENTER 
 
ELECTROTYPE MANIPULATION! 
 
 PART I. 
 
 BEING 
 
 THE THEORY AND PLAIN INSTRUCTIONS 
 
 IN THE ART OF 
 
 WORKING IN METALS, 
 
 BY PRECIPITATING THEM FROM THEIR SOLUTIONS, 
 THROUGH THE AGENCY OF 
 
 GALVANIC OR VOLTAIC ELECTRICITY. 
 BY 
 
 CHARLES V. WALKER, 
 
 Honorary Secretary to the London Electrical Society ; Editor of the Electrical 
 Magazine, Ksemtz's Meteorology, etc. etc. 
 Telegraph Engineer, and Superintendent to the South-Eastern 
 Railway Company. 
 
 ILLUSTRATED BY WOOD-CUTS. 
 FROM THE TWENTY-FIFTH ENGLISH EDITION. 
 
 PHILADELPHIA: 
 HENRY CAREY BAIRD, 
 
 SUCCESSOR TO E. L. CAREY. 
 
 1852. 
 
PHILADELPHIA: 
 K. AND P. G. COLLINS, PRINTERS. 
 
PREFACE 
 
 TO THE LATER EDITIONS. 
 
 The rapid sale of the earlier editions of this work 
 can only be traced to the great popularity of the subject 
 on which it treats. 
 
 No branch of Experimental Philosophy has been more 
 cultivated than Electrotype. Like all, it is replete with 
 interest, whether examined in its theory or in its re- 
 sults — unlike some, it leaves a trace of its* footsteps — 
 a tangible evidence of its power. I allude not to its 
 profitable applications in the hands of the artisan; 
 furnishing, as they do, a full and forcible reply to the 
 oft-proposed question : " What is the use of Electricity?" 
 For him these pages are not written ; his demands upon 
 the art are of another nature, and are intimately con- 
 nected with his own resources. I write for him who 
 delights to devote a portion of his hours of relaxation 
 to the study of those mysteries of nature, into which 
 the eye of science has been able in a degree to pene- 
 trate. It may be safely said, that in the length and 
 
 1* 
 
vi 
 
 PREFACE. 
 
 breadth of England, the proportion of such individuals 
 is far greater than elsewhere; there is amongst us a 
 national love of home, and of 7iome-occupationsj and 
 when we do wander, we feel that we are wanderers ; and 
 can regard with pleasing anticipation the time which 
 will return us to our home. Amongst home attractions 
 is ever found a taste for the fine arts; this is seen even 
 in the cottage, whose walls are adorned with "much that 
 taste, untaught and unrestrained, surveys delighted;" 
 the inmate of the humble tenement, "around whose 
 walls are heroes, lovers, kings," surveys them with a 
 satisfaction closely akin to that which animates the man 
 of cultivated taste, as he views the perfect productions 
 of a Raphael or a Correggio. This taste is abundantly 
 gratified by the discovery of Electrotype; it enables 
 each, who desires it, to furnish himself with durable 
 copies of the finest productions of the chisel and the 
 graver. He finds an inexhaustible field open before 
 him; and, if he devote his time to forming collections, 
 he is animated at every step by the novelty and interest 
 attached to each fresh acquisition. And not the least 
 feature of interest allied to a collection thus formed, is 
 the fact that every specimen is stamped with a double 
 signature of "mine" — "mine" it is by possession — but 
 especially it is "mine" by production. 
 
 When I consider how many copies of this treatise 
 have, during the last year or two, been dispersed through 
 all quarters of our land (and not ours only), I cannot 
 but feel that it has been in some measure instrumental 
 in enabling very many to tread the same pleasing path 
 
PREFACE. Vii 
 
 that I have trodden. I trust my endeavors to pave the 
 way have not been unsuccessful. On first venturing 
 along the new-discovered road, I found many a stumbling- 
 stone besetting my steps; and many a time have I had 
 to survey before I could tell which track would lead to 
 the desired end. These obstacles I have endeavored to 
 remove from the path of those who are interested in 
 following the traces marked out; I have, too, watched 
 with care the progress made by others; and have in 
 each successive edition embodied as much fresh informa- 
 tion as conveniently I could. To my more mature ex- 
 perience on the subject of mould-making; to the general 
 principles on which the reduction of metals is based; 
 and to the description of new arrangements of apparatus 
 which, with revisions of many paragraphs, were given 
 in the earlier editions, I have, in this, added all the im- 
 provements, up to the present time, that I could con- 
 veniently compress into these pages. 
 
 It was at first my intention* to have added observa- 
 tions on the deposition of other metals; this, however, 
 was not found possible; there was so much to be said 
 that could not be contained within the present pages, 
 that I rather determined to unfold fully the principles 
 and practice of the art in this treatise, and to prepare a 
 Second Part, to be devoted to plating, gilding, etch- 
 ing, and all the several applications of the art, which, 
 for want of space, could not be introduced here. In 
 Part II. will also be found the etching of Daguerreotype 
 
 * Preface to Fifth Edition. 
 
Vlll 
 
 PREFACE. 
 
 plates, and several modifications in Voltaic apparatus. 
 In the Fourth Edition of Part II., Electro-Printing is 
 introduced; and the process of plating and etching are 
 dwelt upon more fully. 
 
 CHAKLES V. WALKER. 
 
 Westbourne, August, 1844. 
 
PREFACE 
 
 TO THE EIGHTEENTH EDITION. 
 
 To the former Editions of this little Treatise so many 
 additions had been made, that the arrangement had be- 
 come somewhat irregular. In preparing, therefore, the 
 Sixteenth Edition, I rearranged the whole, rewrote 
 many parts, and added several interesting facts that 
 recent investigations have brought to light. The same 
 are continued in these later editions.* 
 
 C. V. w. 
 
 Tonbridge, June, 1847. 
 
 * In the Twenty-first Edition, I have given a description of 
 Gutta Percha and other moulds, and in the Twenty-third is a 
 new mode of amalgamating. — Feb. 1852. 
 
• 
 
CONTENTS. 
 
 I.— INTRODUCTORY OBSERVATIONS. 
 
 PAGE 
 
 Voltaic Electricity . . . . .14 
 
 Electrolysis . . . . . .17 
 
 Constant Voltaic Battery . . . . .19 
 
 Note on Voltaic Batteries . . . . .21 
 
 II.— PREPARATION OF MOULDS. 
 
 Fusible Metal . . . . . .26 
 
 To make a Mould in Fusible Metal . . 27 
 
 Clichee Moulds . . . . .28 
 
 Wax Moulds . . . . . .31 
 
 Stearine Moulds, &c. . . . .32 
 
 To copy Plaster-Casts . . . . .33 
 
 To render Non-Metallic Moulds conductible . . 34 
 
 Plaster of Paris Moulds . . . . .38 
 
 Elastic Moulds . . . . . .39 
 
 Gutta Percha Moulds . . . . .40 
 
xii 
 
 CONTENTS. 
 
 III.— VOLTAIC APPARATUS TO BE USED. 
 
 PAGE 
 
 Amalgamation . . . . . .42 
 
 New Process of Amalgamation . . . . .42 
 
 Diaphragms . . . . . .43 
 
 Single-Cell Apparatus . . . . .44 
 
 Single Cell without Acid or Mercury . . .46 
 
 Battery Apparatus . . . . .48 
 
 Solutions . . . . . . .49 
 
 Battery Apparatus extended . . . .53 
 
 Smee's Battery . . . . . .55 
 
 New Electrotype Battery . . . . .57 
 
 Electro-Lace . . . . . .58 
 
 Constant Acid Battery . . . . .59 
 
 Prince Bagration's Battery . . . .60 
 
 The Earth a Battery . . . . .60 
 
 Decomposition Cells . • . . .61 
 
 Management of the Moulds . . . .63 
 
 Management of the Battery Apparatus . . .65 
 
 IV. — BRONZING. 
 
 Chemical Bronze . . . . . .69 
 
 Black-Lead Bronze . . > . .71 
 
 Carbonate of Iron, Bronze, &c. . . . .72 
 
 Mounting the Medals . . . ... 72 
 
 V.— CONCLUDING OBSERVATIONS 
 
 73 
 
ELECTROTYPE MANIPULATION. 
 
 L— INTRODUCTORY OBSERVATIONS. 
 
 1. The object of the present treatise is not so much 
 to dwell upon the philosophical principles on which the 
 art of Electrotype is based, as it is to trace in a familiar 
 manner the several processes in manipulation, and the 
 precautions to be observed in order to escape failure. 
 The instructions given are the results of a long course 
 of experiment ; and it will be the especial aim of the 
 writer to dwell minutely upon those little points which 
 so materially influence the success of the experiments. 
 It will be his endeavor to avoid, as much as may be, 
 the use of scientific phraseology ) so that the amateur, 
 for whose use this work is written, may find as few ob- 
 structions as possible besetting his path. In the course 
 of forming a large collection of medals by the electro- 
 type process, and copying casts of large size, the author 
 has, of necessity, been led to adopt such modes as con- 
 venience and economy dictated. These will be described 
 in order, as the reader is led from the original medal to 
 the perfect copy, ready for the cabinet. 
 2 
 
14 
 
 ELECTROTYPE MANIPULATION. 
 
 2. Galvano-plastic, Electrotype, or Electro-inetal- 
 lurgy, is, as its several names indicate, intimately con- 
 nected with Galvanic, or, as it is more fitly termed, 
 Voltaic Electricity. In order, therefore, to convey cor- 
 rect notions on the subject, it will be requisite, before 
 entering on it further, to give a brief outline of the 
 principles of this science, and to trace their application 
 to the art in question. 
 
 3. Voltaic Electricity. — Galvanism, or Voltaic Electri- 
 city, is the name given to that development of electricity 
 discovered in the year 1790, by Professor Galvani, of 
 Bologna, and subsequently more fully investigated by 
 the labors of Volta, whose letter to Sir Joseph Banks, 
 the then President of the Boyal Society,, announcing 
 the discovery of the apparatus, named after him the 
 Voltaic pile, is dated March 20, 1800. It is obtained 
 by certain arrangements of metals and liquids, of which 
 the following may be taken as an illustration. If a 
 piece of zinc and another of copper be attached one to 
 each end of a wire, and the two be then placed in a 
 vessel containing water, acidulated with sulphuric acid, 
 it will constitute a simple or single voltaic pair in 
 ACTION. 
 
 4. The action is dependent on the different chemical 
 affinity of the liquid for the respective metals ; it will 
 dissolve the zinc rather than the copper: in other 
 words, the water (which is well known to consist of the 
 two gases, oxygen and hydrogen, chemically combined) 
 is decomposed; the hydrogen makes its escape at the 
 surface of the copper plate in the form of gas; the oxy- 
 
INTRODUCTORY OBSERVATIONS. 
 
 15 
 
 gen combines with the zinc, and forms an oxide of zinc ; 
 this oxide unites with, and is dissolved in the sulphuric 
 acid, forming sulphate of zinc. Actions analogous to 
 this occur in all voltaic combinations. The exciting 
 liquid has a greater affinity for one metal than for the 
 other. The former is termed the positive metal ) the 
 latter the negative. 
 
 5. For most practical purposes, zinc is used as the 
 positive metal — either pure zinc, the zinc of commerce, 
 or amalgamated zinc (§ 46). For the negative metal, 
 copper is generally used; but a very convenient ar- 
 rangement has been devised by Mr. Alfred Sniee (§ 65), 
 wherein platinized silver — that is, silver covered with 
 minute particles of platinum — is employed. Another 
 battery has been constructed by Professor Grove, of a 
 very powerful nature, wherein plates of platinum are 
 used. There is also a modification of this latter, con- 
 sisting of zinc and charcoal. Charcoal or carbon, being 
 the only other substance in nature, not metallic, which 
 can be so employed. 
 
 6. I have here spoken (§ 4) only of the cliemical 
 change which takes place ; but in connection with this, 
 and bearing a strict relation to it, is another pheno- 
 menon of the highest interest, namely, the disturbance 
 of electric equilibrium. 
 
 7. During the continuance of the chemical changes 
 already described (§ 4), a transfer of electricity is 
 quietly taking place between the two metals. The po- 
 sitive electricity (which, to avoid circumlocution, we 
 will assume to be, as possibly it is, the electricity) 
 
1G ELECTROTYPE MANIPULATION. 
 
 passes from the zinc through the liquid to the copper, 
 and then continues its course along the wire (§ 3), by 
 which the metals are joined, to the zinc again. If the 
 wire is broken, the transfer of electricity is interrupted, 
 and the chemical effects, so far as electricity is con- 
 cerned,* cease; hydrogen is no longer evolved from the 
 copper plate, and the zinc (if it is pure or amalga- 
 mated), ceases to be dissolved. 
 
 8. The fundamental principle, which cannot be too 
 strongly enforced, is, that the passage of the electricity 
 in the liquid is from the zinc to the copper. If this 
 simple fact is borne in mind, it will decide in every 
 case the question which confuses so many, namely, 
 which is the positive and which is the negative end of 
 a battery ? The positive is the end where the elec- 
 tricity leaves a battery ) the negative where it re-enters 
 it. The direction taken by the current being ascertained 
 by the mere inspection of the situations of the two 
 metals in a cell, the other points follow as a necessary 
 consequence. 
 
 9. If, for instance, the wire connecting the two 
 plates (§ 3), by which we have illustrated a single vol- 
 taic pair, were broken, and the circuit completed by in- 
 terposing some apparatus between the broken ends, an 
 examination of the arrangement would at once show 
 that, as the electricity passes from the zinc to the cop- 
 per, it would leave the battery by the wire attached to 
 
 * The ordinary chemical effects of the acid on the zinc 
 continue, unless prevented by other means (§ 46). <* 
 
INTRODUCTORY OBSERVATIONS. 
 
 17 
 
 the copper plate, and, having passed through the inter- 
 posed apparatus, would return to the battery by the 
 wire attached to the zinc plate; the copper, which is 
 the negative metal, forming in this case the positive end 
 of the battery ; and the zinc, the positive metal, forming 
 the negative end. 
 
 10. Electrolysis. — The great effects of voltaic elec- 
 tricity, those which have rendered it so attractive a 
 science, depend on the various modes of combining a 
 large or small number of these pairs of metals, and on 
 the nature of the apparatus interposed between the 
 wires connected with the respective ends of the arrange- 
 ment. The power which, from its effects, Dr. Faraday 
 has termed the Electrolytic* power, is that which alone 
 demands our attention, because on the right understand- 
 ing of this depends the successful application of the 
 art of electrotype. 
 
 11. If a series of about ten of these voltaic pairs or 
 batteries be arranged in the order of zinc, liquid, and 
 copper, and the terminating wires, which for this purpose 
 should be of platinum, be placed in a vessel of water 
 containing sulphuric acid, f the water will be electro- 
 lyzed or decomposed by electricity ; the hydrogen gas 
 will be released at the wire connected with the negative 
 end of the battery, and the oxygen at that connected 
 
 * Vide Exp. Researches. Series 7, \ 664. 
 
 f In this and all other similar instances the use of sulphuric 
 acid is to increase the conducting power of the liquid ; to 
 facilitate the passage of electricity through it. The modus 
 operandi cannot be entered into here. 
 
 2* 
 
18 
 
 ELECTROTYPE MANIPULATION. 
 
 with, the positive. If these gases be collected separately 
 in tubes placed over the platinum wires, the quantity 
 of hydrogen will in bulk be double that of the oxygen. 
 
 12. If into this acid liquid some crystals of sulphate 
 of copper be thrown, and the current be sent through, 
 electrolysis will still take place, the water will still be 
 decomposed, but only one of the gases, the oxygen, will 
 be obtained. The hydrogen, as it becomes released 
 from the water, will take the place of the copper in the 
 solution, and the copper will be liberated and become 
 visible on the negative (§ 8) wire. This experiment 
 may be continued till all the copper is abstracted from 
 the solution • the remaining liquid will be water, 
 strongly acid. 
 
 13. A third modification of this experiment is by 
 using for the positive wire one of copper, instead of 
 platinum. In this instance, too, the water is decom- 
 posed ; but neither of the gases is visible. The hydro- 
 gen, as before, occupies the place of the copper in the 
 solution, releasing the copper as in the last experiment 
 (§ 12) ; the oxygen, instead of appearing at the positive 
 wire, combines with the copper of which that wire is 
 composed, forming an oxide of copper : this oxide 
 unites with the sulphuric acid, and forms a sulphate of 
 oxide of copper. In proportion as the solution is 
 weakened by the release of copper at the negative wire, 
 it is thus supplied with copper from the positive. If, 
 in these experiments, a measuring instrument had been 
 included in the circuit, it would be found that the first 
 of the three presented the greatest resistance, and the 
 
INTRODUCTORY OBSERVATIONS. 
 
 19 
 
 last the least. For, in the last case, the chemical forces 
 were made to conspire with the electric current. 
 
 14. It will be observed, in these illustrations of elec- 
 trolysis, that the metals are released at the negative 
 plate. One part of the science of electrotype — a 
 science discovered in England by Mr. Jordan and Mr. 
 Spencer, and on the continent by Professor Jacobi — 
 consists in preparing for a negative plate models or 
 moulds (§ 20, &c.) of objects to be copied; and in so 
 arranging the battery or apparatus which generates 
 the voltaic current (§ 43, &c.) as to release the metals 
 in a compact and solid form upon these models. 
 
 15. On these two points many precautions are to be 
 observed ; but a faithful compliance with the directions 
 to be given will enable the least skilled to obtain me- 
 tallic copies of the most beautiful works of art, by 
 merely exercising ordinary care and a little patience. 
 
 16. Constant Voltaic Battery. — Before closing these 
 preliminary observations, it will be requisite to give 
 a brief description of the Constant Battery. The 
 voltaic pair immersed in a cell of acid water (§ 8) is 
 liable to some objections. First, the bubbles of hy- 
 drogen released on a common copper plate partially 
 adhere, and of necessity prevent portions of this plate 
 from being in actual contact with the liquid ; and 
 hence its power is less than it might be. The dissolved 
 zinc, too, is partially released and deposited on the 
 copper or negative plate, according to the laws already 
 illustrated (§ 13) ; hence arise counter-currents, which 
 weaken the force. 
 
20 ELECTROTYPE MANIPULATION. 
 
 17. The late Professor Daniell, by the invention of 
 his constant battery, has enabled us to overcome in a 
 very great measure these difficulties — to remove these 
 objections. The deposition of the zinc is obviated 
 by using two liquids, separated by a porous partition, 
 or, as it is called, a diaphragm, of animal membrane, 
 paper (§ 44), earthenware, plaster of Paris, wood,* &c. 
 (§ 48). The liquid contiguous to the zinc is, as before 
 (§ 11), acidulated water ; that near the copper is a so- 
 lution of sulphate of copper.f By this arrangement, it 
 will be seen, from what has been already stated (§ 13), 
 that copper will be released, in place of hydrogen on 
 the copper — the negative plate. 
 
 18. The continuous action of this battery is preserved 
 by amalgamating (§ 46) the zinc, and supplying the 
 cupreous solution with crystals of sulphate of copper 
 (§ 50). The former prevents the acid acting chemically 
 on the zinc (§ 7) and destroying it uselessly : the latter 
 keeps up the strength of the solution, which is being 
 constantly exhausted by the reduction of the copper. 
 Fresh acid water is occasionally added. 
 
 This instrument is termed a constant battery, from 
 its power of continuing a generally steady action for a 
 lengthened period of time. It has been constructed in 
 various ways, being modified according to the taste of 
 individuals, or to the use to which it is to be applied. 
 
 * Lime-tree or some other porous wood, boiled for an hour 
 at least in water containing a little sulphuric acid. — JacobL 
 f This is more properly termed sulphate of oxide of copper. 
 
INTRODUCTORY OBSERVATIONS. 
 
 21 
 
 Fig. 1. 
 
 But whatever form may be given to it, it is still the 
 constant battery, invented by Professor Daniell, to 
 whom alone the credit is due for devising so valuable 
 an arrangement. The wood-cut (Fig. 1) represents a 
 cell of a Daniell' s battery. The cell, being of copper, 
 itself forms the negative metal. A rod of amalgamated 
 (§ 46) zinc is placed, as shown in the 
 figure, within a tube of porous earthenware. 
 Attached to each metal is a binding screw, 
 to form connections. A cell of this de- 
 scription is put into action by placing its 
 several parts as shown in the figure; filling 
 the porous tube containing the zinc with a 
 mixture of one part sulphuric acid and ten 
 parts water; and filling the copper cell 
 with a saturated solution of sulphate of 
 copper. — By saturated is meant a solution 
 containing as muck of the salt of copper as the water 
 will take up. This is prepared most readily by pouring 
 boiling water on a superabundance of crystals of sul- 
 phate, and stirring them; to this solution one-tenth 
 acid should be added. The perforated metal shelf, 
 shown in the figure, is to support a supply of crystals 
 to recruit the exhausted strength of the battery (§ 50). 
 The crystals are placed thus high up in the liquid, 
 because the upper portions are exhausted first; the 
 specific gravity keeps the strong parts of the solution 
 below. 
 
 19. Note on Voltaic Batteries. — While on the sub- 
 ject of voltaic pairs, it will be as well to pen a few 
 
22 
 
 ELECTROTYPE MANIPULATIONS. 
 
 lines on the powers of the battery, which are not di- 
 rectly connected with the art of electrotype. — If a cell 
 of the constant battery be charged as directed above, 
 and a piece of fine platinum wire be stretched from the 
 screw attached to the zinc, to that attached to the cop- 
 per, it will attain a red or a white heat. This is termed 
 the " heating power" of a battery. The larger the 
 cell, the greater, thickness of wire will be heated. If 
 too thin a wire be used, the passage of the electricity 
 will be so much retarded as to produce no visible indi- 
 
 Fig. 2. 
 
 cations of heat. The length of wire that can be heated 
 depends on the cooling power of the contiguous air ; 
 "a current that will heat one inch of platinum, will 
 
INTRODUCTORY OBSERVATIONS. 
 
 23 
 
 heat a hundred inches/ 7 * The law which regulates the 
 comparative length of wires heated by different combi- 
 nations of the batteries appears to be this : If one such 
 cell as that described, heats x inches, and another cell 
 y inches, the two arranged in series will heat x-\-y 
 inches. f 
 
 If a series of cells be arranged, as in the preceding 
 figure, by uniting the copper of one to the zinc of the 
 other, and points of charcoal be attached to the termi- 
 nating wires, upon bringing these points into contact 
 and then separating them, the well known phenomenon 
 of the voltaic flame is produced. The length of this 
 flame depends on the number of cells used ; the size 
 or thickness (if we may use the term) on the size 
 of the cells. The flame from a hundred cells is 
 very brilliant ; in some experiments at which I assisted, 
 made with a series of upwards of three hundred, it was 
 needful to screen the eyes with a black silk veil. J Few 
 things resist the intense heat of this flame ; the metals 
 are speedily dissipated in fumes ; platinum and gold are 
 melted and vaporized. — The arrangement of cells in 
 series will produce a shock on the human frame, intense 
 in proportion to the number in the series. Thirty will 
 produce the effect; three hundred will produce more 
 than a man with ordinary nerves could endure. The 
 
 # Faraday's Researches. Thirteenth Series. $ 1631. 
 f Transactions Electrical Society, p. 63. $ 36. 
 J Since the above lines were written, active exertions have 
 been made to apply this light to ordinary purposes. — June, 1849. 
 
24 
 
 ELECTROTYPE MANIPULATIONS. 
 
 electrolytic power of the battery is only manifested on 
 bodies in solution, or on bodies made liquid by heat ; 
 and these several bodies are acted upon with various 
 degrees of facility. Solution of iodide of potassium is 
 most easily decomposed. A battery consisting of a 
 mere wire of zinc and one of copper, will decompose 
 this solution, even by means of platinum wires. Water 
 is more difficult of decomposition. Ten cells of a DanielPs 
 battery are a convenient number to effect the decompo- 
 sition of water. A series of twenty will release very little 
 more gas than one of ten; but two series of ten placed 
 side ~hy side will do twice the work of one series. By an 
 arrangement of this kind it is that the maximum of de- 
 composing power is obtained from a given number of cells. 
 Chlorides of lead or silver, or chlorate of potassa, &c, 
 &c, do not conduct the current in their solid state, 
 and therefore resist decomposition ; but, when made 
 fluid by heat, they obey the same general law as do 
 solutions. When sulphuret of antimony is fused by a 
 powerful voltaic flame, the heat of the same current 
 will keep it fused, while the current itself decomposes 
 it. — One or two thousand cells containing pairs of 
 plates (copper and zinc) connected in series, and 
 charged with water, produce effects closely analogous 
 to those obtained by the common electric machine. 
 This is termed a water-battery. — There is a beautiful 
 regularity in the action of batteries, that cannot fail 
 to interest the most casual observer : it is a regularity 
 to which the attention of the electrotypist should be 
 especially directed. When a number of cells are con- 
 
INTRODUCTORY OBSERVATIONS. 25 
 
 nected in series according to the plan represented in the 
 wood-cut, precisely the same amount of action occurs 
 in each. If in one an ounce of zinc is consumed, so 
 also is it in every other ; and in each, too, a weight of 
 copper is deposited on the surface equivalent to the 
 ounce of zinc. And if the terminating wires of this 
 apparatus be placed to produce the decomposition of a 
 solution, precisely the same amount of the solution will 
 be decomposed as is equivalent to the quantity of zinc 
 consumed or copper released in each cell. — If water be 
 the subject of experiment, the same arrangement of 
 battery will release more or less gas, according to the 
 degree of conductibility given to the water by means of 
 sulphuric acid ; the less conductible it is, the greater 
 resistance it offers to the passage of the battery current, 
 the less gas is released, and the less zinc is consumed : 
 as the conductibility increases, the rate of decompo- 
 sition is higher, and the energy of the action in each 
 battery cell is greater. There is a harmony in all this 
 consistent with what we have hitherto learned of the laws 
 of nature. The knowledge of this law is no small 
 addition to the science of electricity : and it must not be 
 forgotten, that the development of this beautiful system 
 of things is due to an English philosopher, Faraday, 
 whose perseverance in research has been crowned with 
 unusual success. Without dilating longer on these 
 general features of the science, I shall pursue the object 
 at present in view, and endeavor, with as much brevity 
 as is consistent, to explain the nature of the Electro- 
 3 
 
26 
 
 ELECTROTYPE MANIPULATION. 
 
 type art, with so much of its theory as, joined with 
 what has been already said, may guide the experimenter 
 safely through each process. 
 
 II.— PBEPAKATION OF MOULDS. 
 
 20. I can very reasonably conclude that the amateur 
 will commence his experiments on the smaller works of 
 art ; and, as a knowledge of the mode of manipulation 
 to copy these will, with a little practical experience, 
 easily pave the way towards accomplishing greater 
 things, I shall dwell principally on the art of copying 
 medals, medallions, seals, &c, taking the reader with 
 me through the entire process. 
 
 21. There are many materials fitted for forming 
 moulds; of these — -fusible metal, wax, stearine, gutta 
 percha, and a composition whose base is spermaceti, 
 are mostly used. The first is applicable to all medals 
 of ordinary size — the others to plaster medallions and 
 larger medals. 
 
 22. Fusible Metal. — This is an alloy, consisting of 
 bismuth, tin, and lead ; it melts at a low temperature 
 — a few degrees below that of boiling water ; and has 
 been used as a philosophical toy, in the form of spoons, 
 which melt in hot tea. For the latter purpose, it gene- 
 rally contains a small portion of mercury. Since the 
 discovery of electrotype, it has been prepared for that 
 process without mercury. 
 
PREPARATION OF MOULDS. 
 
 27 
 
 23. The proportion of the different ingredients in a 
 pound of this alloy is : — 
 
 oz. 
 
 Bismuth . . . .8 
 
 Tin ..... 3 
 Lead . . . .5 
 
 16 = 1 lb. 
 
 These should be melted together in a clean iron ladle, 
 taking care to keep it on the fire no longer than is 
 necessary to produce the complete liquefaction of the 
 several ingredients. When melted, pour the metal on 
 a stone or marble slab in drops. Then, after having 
 rubbed the ladle clean with coarse paper, return the 
 pieces of metal, re-melt them, and pour them out in 
 drops as before. A third melting will insure the 
 ingredients being well mixed. To retain the metal in 
 a fit condition for use, the ladle must be frequently 
 rubbed clean ; and must always be removed from the 
 fire as soon as its contents are melted. The former 
 insures a bright surface to the mould ; the latter pre- 
 serves the alloy from waste by oxidation. 
 
 24. To make a Mould in Fusible Metal. — Melt some 
 in the iron ladle, and pour it on a slab ; then, from the 
 height of two or three inches, drop on it the medal to 
 be copied, taking care that the medal is cold. In a 
 few seconds the metal will be solid, and may be placed 
 to cool; when it is cold, either with or without a few 
 slight taps, the two will separate : and, if proper 
 care has been taken, an exceedingly sharp mould will 
 
28 
 
 ELECTROTYPE MANIPULATION. 
 
 be obtained. The novice must not, however, be dis- 
 heartened if his first attempts to obtain good moulds 
 fail : for there are so many little accidents which may 
 happen, that the most practised manipulator may have 
 to repeat his attempts. A slight shake of the hand 
 may drop the medal irregularly; too much sunk, for 
 instance, on one side. A film of oxide may rest on a 
 portion of the surface of the melted metal, and render 
 the corresponding portion of the cast dull. Dull look- 
 ing moulds must always be rejected; for so minutely 
 correct is the process of electrotype, that the dul- 
 ness of the mould will be transferred to every copy 
 made from it. Even if an original medal be incau- 
 tiously handled, the slight trace of a finger-mark will 
 be transferred to the mould ; and thence to the electro- 
 type copies. 
 
 25. The fusible metal will not always pour into a 
 round mass, to receive the medal : unless the slab is 
 perfectly level, it runs into a stream. This is a 
 great inconvenience, but may be remedied by having a 
 shallow cavity (saucer fashion) made in the marble ; 
 or by using any article of earthenware, which the 
 kitchen or the laboratory may furnish, suited to the 
 purpose. I have been in the habit of using the brown 
 stoneware saucers, in which blacking is sold ; and in 
 them have produced some of the best moulds. They 
 are to be inverted, and the metal is to be poured on 
 them. 
 
 26. Clicliee Moulds. — The following is the mode 
 adopted on the Continent for obtaining the beautiful 
 
PREPARATION OF MOULDS. 
 
 29 
 
 casts of the French medals, which are so much admired. 
 These casts are in a fusible alloy, containing antimony, 
 as well as the other ingredients (§ 23). The composi- 
 tion is : — * 
 
 Bismuth ..... 8 parts 
 Tin . . . . . 4 
 
 Lead . » . . . . 5 
 
 Antimony ..... 1 
 
 The metals should be repeatedly melted and poured into 
 drops, until they are well mixed. 
 
 27. A block of wood is then turned into a shape 
 similar to that of a button-die, into one end of which is 
 worked a cavity, the size of the medal to be copied, 
 and not quite so deep as its thickness; in this cavity 
 the medal is placed; should it not fit tightly, a circle 
 of paper is pressed in with it; the medal, being thus 
 firmly mounted, is to be copied in the following 
 manner : — - 
 
 28. A sheet of smooth cartridge-paper is fixed, by 
 drawing-pins or otherwise, within side a box having sides 
 about four inches high, which slope inwards in order 
 to prevent the metal from being scattered away; the 
 part to be used is very slightly oiled with a single drop 
 of oil; on this is poured some of the prepared alloy, 
 which should be removed from the fire as soon as melted 
 (§ 23). The metal is then stirred together with cards 
 until it assumes a pasty appearance, and is on the eve 
 
 * Vide Proceed. Elee. Soc. part ii. p. 90, Aug. 17, 1841. 
 
 3* 
 
30 
 
 ELECTROTYPE MANIPULATION. 
 
 of crystallizing; if, at this stage, the surface should 
 appear defaced with dross, one of the cards must be 
 passed over it lightly and speedily; should no dross 
 appear, this part of the process may be omitted. The 
 die containing the medal must then be held firmly in 
 the right hand, and be struck gently and steadily upon 
 the solidifying metal. Should an assistant be at hand 
 to aid in this, it will be as well ; for sometimes during 
 the brief interim, while the card is being exchanged for 
 the die, the exact moment is lost, and the mould is im- 
 perfect. When one stirs the metal, and the other is 
 prepared with the die, the operation can be timed to a 
 nicety. When an assistant is not at hand, the die 
 should be placed within reach of the right hand, with 
 the medal downwards. A little ingenuity "will readily 
 suggest the construction of a press, by which this part 
 of the process could be accomplished. Large medals 
 are moulded without the die, by dropping them in a 
 sidelong direction upon the solidifying metal. 
 
 29. The beauty and perfection of moulds thus ob- 
 tained will amply repay the trouble of producing them 
 — though I am not quite justified in using the word 
 "trouble" — for by this mode, with ordinary care, two 
 out of every three casts are perfect; besides, therefore, 
 the economy of time, the saving in the reduced oxi- 
 dization of metal is thus of no inconsiderable importance. 
 
 30. This method of producing moulds is not confined 
 to obtaining them from medals, which melt at a high 
 temperature; they may be obtained from the common 
 soft, white metal, with little danger of damaging the 
 
PREPARATION OF MOULDS. 
 
 31 
 
 original. They may also be obtained from the metallic 
 casts, which are extant, of the French medals of Andrieu, 
 &c. Moreover, if the fusible mould itself be cut round 
 and fitted into the block in place of the medal, it may 
 be employed as a die j and casts, perfect casts, equal in 
 respect to fidelity, and similar to the original medal, 
 may be obtained. 
 
 31. Having obtained a mould, varnish the back and 
 edge — and also a portion of the front, when the surface 
 of the mould around the impression is larger than 
 necessary. The best varnish is good sealingwax, dis- 
 solved in spirit of wine; but for immersion in the 
 cyanide solutions to be described hereafter (§ 95), wax, 
 or, which is better, pitch must be used. It will now be 
 ready for use, and is to be attached to a copper wire. 
 The end of this wire must be quite clean; the wire is 
 placed across the flame of the candle, with the clean end 
 beyond the flame; it is to be touched with a piece of 
 rosin, and pressed on the edge of the mould. The 
 mould will instantly melt to receive it, and in a few 
 seconds it will be cold and firmly fixed. The moulds 
 should be wrapped in paper, if they are not intended for 
 immediate use. 
 
 32. Wax Moulds. — The manipulation with this ma- 
 terial is very simple. The wax employed is the common 
 white wax, or the ends of wax candles. It is to be 
 melted in an earthen pipkin or a small jug, and kept 
 by the fireside a few minutes after it is well melted. 
 The medal to be copied should be made warm — the 
 warmer the better (the object being to prevent the 
 
32 
 
 ELECTROTYPE MANIPULATION. 
 
 sudden chill of the wax when poured on). It is to 
 be surrounded with a rim, composed of a ribbon of 
 pasteboard. The end of this may conveniently be 
 secured by a small cleft stick. The surface of the 
 medal should be very slightly covered with olive oil. 
 The hot wax is then poured on. It may require five or 
 six hours to become sufficiently cold for removal ; and 
 great care must be taken to allow the cooling process 
 to be gradual ; for, without this precaution, the moulds, 
 especially when of large objects, are apt to split. There 
 will be at times a difficulty in removing wax moulds 
 from medals with elaborate work. This may be ob- 
 viated by a little care : the medal should be very 
 slightly warmed by the heat of a candle, so as to cause 
 a trifling expansion of the metal ; and the wax is then 
 to be drawn cautiously, and at right angles, from the 
 surface of the medal. This applies to other composi- 
 tion moulds. 
 
 33. Stearine Moulds, &c. — From a few practical in- 
 conveniences attendant on the use of wax, I have at 
 times preferred stearine, and consider it on the whole 
 very useful, especially in copying works in metal j but 
 recent experience has taught me that a still better ma- 
 terial, is a composition consisting of 8 oz. of spermaceti 
 to If oz. each of wax and mutton suet. The Rev. F. 
 Lockey recommends a mixture of wax, stearine, and 
 black-lead. On this hint, I have added black-lead to 
 some of my compositions, and with advantage. Since 
 writing this paragraph, I have examined some moulds 
 made with wax and a little of what is termed Flake- 
 
PREPARATION OF MOULDS. 
 
 33 
 
 ivliite, and never saw any to equal them — nay, not even 
 the metal moulds. 
 
 34. That such compositions will produce minutely 
 correct copies of plaster casts renders them invaluable 
 to the electrotypist, who employs his scientific resources 
 towards the formation of a collection of worlds of art. 
 For he is thus enabled to transfer impressions from the 
 frail and perishable plaster to the durable copper ; and to 
 transfer them with all their beauty and all their perfec- 
 tion. They who have obtained but a casual insight into 
 the treasures transferred to this delicate, but brittle mate- 
 rial, have seen enough to assure them that there is an 
 ample store to suit every taste and every temper. For 
 a few pence, specimens of first-rate execution may be 
 obtained from any of the plaster-shops in London. 
 
 35. To copy Plaster- Casts. — Pour some hotting water 
 into a plate ; stand the cast, face upwards, in this 
 water : the water must not be deep enough to reach the 
 face of the cast. In a few minutes, the cast will be 
 filled with water.* Then, without loss of time, wrap 
 round it a ribbon of pasteboard as before (§ 32), and 
 immediately pour in the melted composition. After it 
 becomes solid, let it remain for two or three hours, and 
 the mould may generally be lifted off from the plaster, 
 without further trouble. 
 
 36. This, however, is not always the case, for if the 
 
 * The small delicate casts, which are slightly tinted, are 
 best copied by first moistening their surfaces with olive oil, and 
 then pouring on the wax. 
 
34 
 
 ELECTROTYPE MANIPULATION. 
 
 water with which the plaster is soaked be too cool, or 
 if the cast be not perfectly saturated, the wax will ad- 
 here ; and, even with every care, this will at times be 
 found to occur, on account of imperfections in the 
 structure of the cast. Unless the latter has been cast 
 from good plaster, very well mixed and stirred, it will 
 be of a rotten texture, and will readily break off in frag- 
 ments after it has once been wetted ; and these frag- 
 ments will adhere to the mould. Having thus destroyed 
 the cast, it is an object of some importance to preserve 
 the mould by removing the fragments without affecting 
 the wax surface. This is readily done by gently touch- 
 ing each spot of plaster with a wire dipped in sulphuric 
 acid ; and then leaving the cast exposed to the air for 
 ten or twelve hours. The acid will gradually absorb 
 moisture from the atmosphere, and their mutual action 
 will so disintegrate the plaster, that it may be entirely 
 washed away with a earner s-hair brush and cold water. 
 
 37. To render Non- Metallic Moulds, Conductihle. — 
 But wax, and such like bodies, are non-conductors; 
 and, as such, will not be of any service to convey 
 the voltaic current. In order to render their surface 
 conductible, many plans have been devised. There is 
 one which combines the three advantages' of simpli- 
 city, certainty, and economy. It is, to cover the sur- 
 face with black-lead ; the application of this substance 
 was recommended by Mr. Murray ; it was also employed 
 by Prof. Jacobi, and its management is described in his 
 
 " GrALVANO-PLASTIC." 
 
 38. This article is known in commerce under the 
 
PREPARATION OF MOULDS. 
 
 35 
 
 several names of plumbago, graphite, and black-lead. 
 The latter might naturally enough induce those unac- 
 quainted with the subject to conclude that lead held 
 a prominent place in its composition. This, however, 
 is not the case ; it contains no lead at all ; it consists 
 of carbon and iron the principal portion being carbon. 
 Plumbago is largely used in the arts ; the finer sorts 
 for drawing-pencils, the inferior in domestic economy, 
 for polishing iron-work. It does not seem that the 
 difference of quality in this substance depends entirely 
 upon the quantity of carbon it contains. The common 
 qualities, such as are used for polishing stoves, are 
 very good conductors ; but, unfortunately, the common 
 kinds are often largely adulterated. The philosophical 
 instrument-makers, who sell the apparatus for Electro- 
 type experiments, generally keep plumbago in a fit con- 
 dition for applying wax to moulds. 
 
 39. It may be applied dry. Having breathed 
 slightly on the mould, dip a soft brush into the plum- 
 bago, and rub it briskly over the surface : continue 
 this, breathing on it occasionally, till the whole presents 
 the well-known black-lead polish. Be very careful to 
 rub the brush into every spot. The best kind of brush 
 is a strong and fine camers-hair pencil. With care, 
 this operation will not affect the sharpness of the 
 mould in the slightest perceptible degree. When the 
 mould seems to be covered, if, upon breathing on it, 
 any parts appear whitish, repeat the operation. — In 
 
 Its chemical name is carburet of iron. 
 
36 
 
 ELECTROTYPE MANIPULATION. 
 
 some cases the black-lead may be applied wet, and after- 
 wards polished. — Messrs. Elkingtons used the following 
 mixture, instead of mere plumbago : Zinc is melted 
 in an iron ladle until near the point of burning, when 
 a few pieces of iron are dropped into it. When cold, 
 the mixture is very friable. They reduce it to a fine 
 powder, and mix it with plumbago, which they apply 
 as before. — A clean wire slightly warmed, and pressed 
 against the back of the mould, will become firmly 
 imbedded in it. Then rub the wire and the wax about 
 it with the plumbago brush, in order to complete the 
 connection between the two. It is advisable to re- 
 move any plumbago which may have been spread on 
 the edges of the mould, by scraping them with a knife. 
 The mould is then ready for use, if small ; but if large, 
 the u guiding-wires," recommended by Mr. Phillips, of 
 St. Austell, may be occasionally added with advantage. 
 One or more thin wires are twisted round the main 
 wire, and their ends are allowed to rest against different 
 parts of the mould, especially in the recesses of deep 
 relief ; and thus the copper may be led to deposit over 
 all parts of the surface in a short time. When this is 
 effected, the guiding-wires are carefully removed. — 
 Sealingwax impressions are coated with plumbago. 
 To cause it to adhere, moisten the seal slightly with 
 spirit of wine, or expose it to the vapor of ether. For 
 delicate objects, as flowers, insects, &c, which cannot 
 withstand the action of brushing, other modes must be 
 adopted. One method is to dip the article in a weak 
 solution of nitrate of silver, and while moist to expose 
 
PREPARATION OF MOULDS. 
 
 37 
 
 it to the vapor of phosphorus, under a tumbler or bell- 
 glass. , The vapor is procured by placing a watch-glass, 
 containing phosphorus dissolved in alcohol, in a saucer 
 of hot sand. By this operation, the metal silver is re- 
 duced from its nitrate; and thus the surface of the 
 article is made conductible. This process has, in some 
 cases, been adopted conjointly with the plumbago; on 
 large objects, the black-lead surface has been painted, 
 first with nitrate of silver in solution, and then with the 
 solution of phosphorus. The silver is sometimes re- 
 duced by the action of light; the same object has been 
 also accomplished by allowing a jet of sulphurous acid 
 gas to impinge on the surface moist with the nitrate. 
 The best preparation of phosphorus, however, is its so- 
 lution in bisulphuret of carbon. This highly inflam- 
 mable and very volatile compound greedily dissolves 
 phosphorus; but about ^tih part of phosphorus will be 
 found sufficient. The object is merely dipped in this; 
 and, after a few seconds, is immersed for a short time in 
 a weak solution of nitrate of silver, and then allowed to 
 dry in the light. The greatest care must be exercised 
 in these operations; for the articles themselves will 
 often inflame spontaneously, if allowed to remain, after 
 having been in the phosphorus solution; — it must not 
 be dropped about ; for, although apparently innocent at 
 the moment, it may afterwards ignite, and cause very 
 serious accidents. It must not be allowed to insinuate 
 itself beneath the nails of the hand. A preparation of 
 wax, containing a little of this solution, is sometimes 
 4 * 
 
38 
 
 ELECTROTYPE MANIPULATION. 
 
 used; it is melted, and the objects, when dipped in, need 
 no further preparation.* 
 
 40. Plaster of Paris Moulds. — Another mode of 
 making moulds is with fine plaster. They are to be 
 saturated with wax or tallow, by standing them in a 
 shallow vessel containing these , substances in a melted 
 state, or they may have their surfaces covered with fine 
 varnish if the work will permit it; or they may be 
 heated with hot boiled oil, containing a little beeswax; 
 and when cold they are to be coated with plumbago 
 (§ 34). The best fine plaster should always be used; it 
 should be fresh; if kept any time, it must be preserved 
 from the air in jars or otherwise. In mixing, water is 
 first poured into a lipped basin ; the plaster is gradually 
 dropped in, and the supernatant water poured away ; the 
 water which remains with the plaster is the proper pro- 
 portion to be stirred with it : when well mixed, let a 
 small quantity be brushed into all the work of the medal 
 with a carneF s-hair pencil; this removes air-bubbles: 
 
 * The following preparation is also used : A pound of wax 
 or tallow is melted; to this is then added a solution consisting 
 of 2 oz. of India rubber and 1 lb. of asphalte dissolved in a pint 
 of spirits of turpentine. To this is added a pound of a solu- 
 tion of phosphorus in bisulphuret of carbon, in the proportion 
 of 1 part of the former to 15 of the latter. The articles are 
 attached to a wire, and dipped into this mixture ; they are then 
 dipped in a weak solution of nitrate of silver, and when the 
 black appearance of the silver is manifested, they are removed 
 and washed in water; they are afterwards dipped in a weak 
 solution of chloride of gold, and then washed. They are now 
 coated with gold, and are ready for the electrotype process. 
 
PREPARATION OF MOULD. 
 
 39 
 
 then pour on the plaster to the thickness required. If 
 the objects to be copied be lightly oiled first, little diffi- 
 culty will be experienced in removing the plaster-mould 
 when "set" Fusible moulds will, with proper care, 
 produce successively as many electrotype copies as the 
 operator pleases. Wax or composition moulds are most 
 commonly damaged more or less, in removing the de- 
 posit. 
 
 41. When the object is undercut, the plaster-mould 
 may be made in pieces ; and when put together in a 
 mother-piece, the joinings must be modelled up. I have 
 adopted this plan in some electrotypes of Thorwalsden's 
 " Triumph of Alexander;" in others, I have made the 
 mould on the plaster-cast, and have then broken the lat- 
 ter carefully away, so as to leave me a mould in a single 
 piece. In either case, the mould requires to be broken 
 away from the Electrotype. 
 
 42. Elastic Moulds. — Three parts of treacle are added 
 to twelve parts of glue that has been carefully melted, 
 and the whole is well incorporated. Metal and other 
 objects, which would not "deliver" on ordinary moulds, 
 on account of their high relief, may be readily moulded 
 by this preparation, which will stretch during the re- 
 moval of the mould, and will readily return to its origi- 
 nal form. 
 
 Another Plan. To a pound of gelatine or of the 
 best fish glue, add three-quarters of a pint of water and 
 half an ounce of beeswax, and dissolve it over the fire 
 in the way of ordinary glue : use it when at about the 
 consistency of syrup. The plaster-cast must be oiled 
 
40 
 
 ELECTROTYPE MANIPULATION. 
 
 before the mould is taken from it. This is Mr. Mitch- 
 ell's plan, and may be at times useful. 
 
 Gutta Percha Moulds. — This material will be found 
 very valuable. In making moulds from metal originals, 
 a piece is to be cut from a sheet of gutta percha about 
 the size required ; and, after being softened in water at 
 the temperature of 150° or 160°, is to be pressed by 
 screw-pressure or otherwise into the medal. Plaster 
 originals may be copied most accurately, without un- 
 dergoing any previous preparation, by the employment 
 of gutta percha macerated with a little coal naphtha. 
 This preparation is made very plastic by warm water, 
 and does not require much pressure to produce most 
 faithful copies, and without damaging the cast. It is 
 more convenient to purchase it prepared than to make 
 it. It may be obtained of the publishers of this book. 
 
 Coating Glass. — It is often desirable to coat glass 
 vessels with copper for chemical purposes. Expose the 
 glass to fumes of hydrofluoric acid, to roughen it, when 
 the vessel is of such a shape that the copper might 
 easily leave the glass ; in other cases, as in flasks, this 
 part of the operation may be omitted. Then varnish 
 and black-lead the vessel. Use copal varnish, or two 
 parts of asphalte and one of mastic in oil of turpentine, 
 or gutta percha solution. 
 
VOLTAIC APPARATUS TO BE USED. 
 
 41 
 
 III.— VOLTAIC APPARATUS TO BE USED. 
 
 43. The moulds thus prepared are fitted to fill the 
 place of the negative or copper plate, in the generating* 
 cell of a simple constant voltaic pair (§ 17); or of the 
 negative plate in a decompositionf cell. In either case 
 they occupy the place where hydrogen is evolved, if the 
 liquid is acid water (§§ 4, 11) j and where copper is 
 reduced, if this acid water contains sulphate of copper 
 (§§ 12, 13, 18). 
 
 44. For the simplest mode of obtaining an Electro- 
 type medal, the reader is referred to the description 
 given (§ 3), of a single voltaic pair. Instead of using 
 the copper-plate as there described, attach (§ 31) to the 
 end of the wire one of the fusible moulds (§ 24). Bend 
 the wire into the shape of the letter f| > so that the 
 mould shall face the zinc : wrap the zinc in a piece of 
 brown paper; pour within the paper some salt and 
 water, or some water very slightly acidulated with 
 sulphuric acid; and immerse the whole into a vessel 
 containing a saturated (§ 18) solution of sulphate of 
 copper, having a little acid in it. 
 
 45. This apparatus will represent a single cell of a 
 constant battery (§ 17) ; not constructed on the best 
 
 * This term is applied to that cell containing the single vol- 
 taic pair of zinc and copper, or other metal (f 3). 
 
 j- This term is applied to the second cell, into which the 
 terminating wires (g§ 11, 12, 13) are brought. 
 
 4* 
 
42 
 
 ELECTROTYPE MANIPULATION. 
 
 principles, it is true, but sufficiently so for an introduc- 
 tory experiment. The copper of the solution will be 
 released on the fusible mould (§ 17) ; after a few min- 
 utes' immersion, the mould will be covered with a very 
 brilliant coating of pure metallic copper ; after thirty 
 hours, or less, with proper arrangements (§ 58), this 
 coating will be thick enough to remove. 
 
 46. Amalgamation. — To complete, however, the cha- 
 racter of this constant voltaic pair, the zinc must be 
 amalgamated ) for besides the electric action into which 
 common zinc may enter, the acid acts on it chemically. 
 This partly arises from the quantity of foreign matter 
 contained in the zinc of commerce : this matter, which 
 is mostly metallic, forms, with the particles of zinc, 
 very many small voltaic pairs, all acting independently 
 of the negative plate (§§ 3, 17), and at the expense of 
 the zinc and acid. Pure zinc, which may be obtained 
 where electrotype apparatus is sold, is not to this extent 
 destroyed. 
 
 47. The process of amalgamation is this : Place 
 some mercury in a saucer or plate ) pour on it some 
 water and sulphuric acid ; brush the liquid and mer- 
 cury over the surface of the zinc, till the whole is 
 covered with a bright coat of mercury.* 
 
 * New Process of Amalgamation. — At the meeting of the 
 British Association in 1849, Mr. Walenn gave the following 
 process of Amalgamation: " After the plates are cleaned with 
 emery, immersion in dilute sulphuric-acid, and then in water, 
 they are dipped into a mixture of about equal parts by measure 
 of saturated solutions of chloride of mercury (corrosive subli- 
 
VOLTAIC APPARATUS TO BE USED. 
 
 43 
 
 48. Diaphragms. — But the paper diaphragm above 
 mentioned is very inconvenient in experiments of any 
 duration; it seldom, perhaps never, prevents the partial 
 mixing of the liquids ; and its use is always attended 
 with a great waste of the sulphate of copper. The 
 same may be said, though in a less degree, of animal 
 membrane. Either will do very well for solitary ex- 
 periments; but something more substantial and more 
 durable is requisite. For this purpose porous tubes 
 have been constructed of the material used for butter- 
 coolers : others have been made of pipe-clay. 
 
 49. Very good diaphragms are easily made from 
 plaster of Paris ; and for this purpose the coarse 
 plaster used by builders is best, care being taken to 
 have it as new and fresh as possible : it is mixed with 
 water in the usual way (§ 40), and is poured into a 
 mould of the following construction : A core is turned 
 out of hard wood, nearly cylindrical, but a little smaller 
 
 mate) and acetate of lead ; they are then rubbed with a cloth, 
 and are ready for use. The superiority of this method of 
 preparing the plates consists in the fact that local action is 
 entirely prevented, and they only require one preparation until 
 they are quite dissolved ; they are not so liable to break as 
 common amalgamated plates are, and are therefore able to be 
 used as long as any metal remains. They are also more highly 
 positive than common amalgamated zinc plates." 
 
 Should this process be found in practice to maintain the cha- 
 racter here assigned to it, it will be of unquestionable value. 
 I am testing it on an extensive scale, with batteries that will 
 be required to remain efficient for many months together. 
 
44 
 
 ELECTROTYPE MANIPULATION. 
 
 at one end, in order that it may draw out of the 
 diaphragm when made ) the thicker end has a shoulder 
 rising a quarter of an inch or more beyond the surface 
 of the core, according to the thickness required to be 
 given. This, as well as the length and diameter of the 
 core, will depend on the kind of diaphragm required. 
 A thin sheet of tin or copper is now tied round the 
 shoulder ; and plaster being poured between the core 
 and the envelop, a diaphragm is readily made. These 
 diaphragms are very durable; and will be found a great 
 acquisition to those who, from local circumstances, may 
 not be able to obtain other kinds of porous ware. 
 
 50. If, in the introductory experiment already 
 described, the amalgamated zinc and these diaphragms 
 be employed, a constant battery is obtained, with all 
 its parts complete. And if, in addition, a bag of 
 crystals of sulphate of copper be hung in the blue solu- 
 tion, in order to recruit its strength, and the acid 
 water around the zinc be occasionally renewed, the 
 action may be continued for days or even weeks. And 
 by removing the mould as soon as a sufficient thick- 
 ness of copper is obtained, and supplying its place by 
 another, three or four medals may be copied in a week. 
 
 51. Single-cell Apparatus. — The annexed wood-cut 
 (Fig. 3) represents the single-cell apparatus in its com- 
 plete form, z is a rod of amalgamated zinc, m the mould, 
 w the wire joining them, c the copper solution, p a tube 
 of porous earthenware, containing a solution of acid and 
 water. To put this in action, pour in the copper solu- 
 tion, fill the tube with the acid water, and place it as 
 
VOLTAIC APPARATUS TO BE USED. 45 
 
 shown in the figure. Last (§ 75) of all put in the bent 
 wire, having the zinc at one end and the mould at the 
 other. Another form of this apparatus is here given 
 (Fig. 4). The zinc is connected by a wire and binding 
 
 Fig. 3. Fig. 4. 
 
 screws with a metal rim ) and on the latter can be hung 
 several moulds, as in the drawing. Things are much 
 more likely to go on well when several moulds, as thus, 
 are operated on, than when only one is introduced. 
 The reason will be manifest hereafter. 
 
 52. The following precautions must be observed in 
 using this apparatus : The copper solution must be kept 
 saturated, or nearly so ; this is effected by keeping the 
 shelf well furnished with crystals. The mould must 
 not be too small in proportion to the size of the zinc. 
 The concentrated part of the solution must not be 
 allowed to remain at the bottom. In the latter case, 
 the copy will be irregular in thickness — in the former, 
 
46 
 
 ELECTROTYPE MANIPULATION. 
 
 the metal may be a compact brittle mass; or may be 
 deposited in a dull red, a violet, or a black powder. 
 The nature of these several depositions will be elsewhere 
 alluded to (§ 62, &c); so will also the relative pro- 
 portions of the zinc, &c. (§ 78). 
 
 53. Single Cell without Acid or Mercury. — The tyro 
 must not imagine from the above descriptions that acid 
 and mercury are the sine qua non of success; because 
 either of the above apparatuses would be effective, though 
 in a feebler degree, by charging the porous tube with a 
 solution of sal-ammoniac, or even with one of common 
 
 salt, and using zinc in its ordinary state, and employing 
 a neutral solution of sulphate of copper. Sal-ammoniac, 
 or hydrochlorate of ammonia, consists of ammonia and 
 
 Fig. 5. 
 
VOLTAIC APPARATUS TO BE USED. 
 
 47 
 
 muriatic acid. Its electro-chemical analysis is too com- 
 plex to need a place here. Table salt or chloride of 
 sodium, consists of the gas, chlorine, and the metal, 
 sodium : its action is, that the chlorine combines with 
 the zinc, and forms the very soluble chloride of zinc ; 
 and the sodium combines with the oxygen, that would 
 be nascent at the diaphragm, and forms soda. This ar- 
 rangement is not so powerful as the other, because the 
 sum of the favorable, minus the unfavorable, affinities is 
 less in the one case than in the other. 
 
 54. A single-cell apparatus may consist of a wooden 
 box, as shown above (§ 53), well varnished in the in- 
 terior, and divided into two unequal cells by a partition 
 of porous wood. The wood is prepared as described 
 above (§ 17). The larger cell is filled with a saturated 
 solution of sulphate of copper, the smaller with a half- 
 saturated solution of muriate of ammonia, or one of 
 common salt. In the former is a shelf for containing a 
 supply of crystals. 
 
 55. I do not recommend the use of the single-cell 
 arrangement, except for small objects ; I do not adopt it 
 on the large scale. Seals are electrotyped by the sim- 
 plest form of the single cell : a warm wire is pressed 
 into the edge of the seal, which is then covered with 
 plumbago; the other end of the wire is twisted to a 
 little piece of zinc, or even an iron nail, and the wire is 
 bent p| fashion : a little diaphragm of card, sewed up, 
 having the joinings secured with wax, is filled with 
 water containing a pinch of salt, or a few drops of acid; 
 this is placed in a tumbler of sulphate of copper ; and 
 
48 
 
 ELECTROTYPE MANIPULATION. 
 
 the seal is immersed in the copper solution, while the 
 other end of the wire, with its attached metal, is within 
 the other liquid. — While upon seals, I may mention, 
 that their electrotypes are easily backed up with lead. 
 When fresh from the solution, let them be varnished 
 with rosin, dissolved in ether, or otherwise; after which, 
 there will be no difficulty in causing the adhesion of tin 
 or of soft solder, when required. Under other circum- 
 stances, the best means of tinning is to wash the metal 
 with a solution of chloride of zinc and sal-ammoniac. 
 Mr. Lockey recommended stearine instead of rosin. 
 
 56. Battery Apparatus. — A valuable improvement 
 was devised in Russia, by Professor Jacobi,* and in 
 England by a Member of the Electrical Society, Mr. 
 Mason.f It consists in using a decomposition cell, 
 analogous to that already described (§ 11). The con- 
 stant voltaic pair (§ 17), of copper and zinc is used 
 as the generating cell. To the end of the wire 
 attached to the copper is fastened a plate of copper : to 
 the end of the wire attached to the zinc is affixed the 
 mould. The sheet of copper and the mould are placed 
 face to face in the decomposition cell. This arrange- 
 ment will be better understood from the annexed figure. 
 A is a cell of Daniell's Battery (§§ 17, 50); B the de- 
 composition cell, filled with the dilute acid solution 
 of sulphate of copper ; c the sheet of copper to furnish 
 
 * Vide Jacobi' s Galvano-Plastic. 
 
 f Vide Proceedings of the Electrical Society, April, 1840, p. 
 203. 
 
\ 
 
 VOLTAIC APPARATUS TO BE USED. 49 
 
 a supply ) m the moulds to receive the deposit. To 
 charge this, pour in the several solutions : hang a piece 
 of copper on the brass rod c; connect this rod with the 
 
 Fig, 6. 
 
 copper of the generating cell by the wire z ; and the 
 other rod rn, with the zinc, by the wire x ; then, and 
 not till then (§ 51), hang the moulds on the rod m. 
 
 57. Solutions. — The solution used in this decompo- 
 sition cell or depositing trough, greatly depends on the 
 battery or power employed ; with a cell of Daniell's 
 Constant Battery, a solution of about 2 sulphate of 
 copper by measure, and 1 acid water (1 acid + 9 
 water), is undoubtedly the best. When less power is 
 employed, a little acid in addition is found to be advan- 
 tageous. 
 
 Professor von Kobell, instead of mixing acid water 
 with the saturated solution of sulphate of copper, adds 
 solutions of Glauber's salt, or of potash alum, or of 
 nitrate of potash j by which means he obtains deposits 
 of very malleable copper. Glauber's salt appears to be 
 5 
 
50 
 
 ELECTROTYPE MANIPULATION. 
 
 the best ; it renders the solution more conductible, and 
 is not itself decomposed by such feeble currents, as are 
 here in use ; while its solution will take up as much 
 sulphate of copper as common water does. Two of 
 saturated solution of sulphate of copper, and one of 
 sulphate of copper in solution of Glauber's salt, are 
 stated to be good proportions. 
 
 To the ordinary solution of sulphate of copper, the 
 Messrs. Elkingtons add caustic potash or soda in small 
 quantities, until the precipitate is no longer redissolved 
 by the solution, and they thus obtain a solution for the 
 precipitating trough which gives up a greater quantity 
 of copper for a given battery action, and gives it up also 
 in a less space of time. 
 
 58. By an action already illustrated (§ 13), the cop- 
 per from the solution is transferred to the mould ; and 
 the copper sheet is dissolved, being converted with the 
 sulphuric acid into sulphate of copper ; thus keeping up 
 the strength of the solution. The time is somewhat 
 longer by this method : two days will produce a medal 
 of very good substance, firm and pliable. In speaking, 
 however, of the time required for these experiments, it 
 must be borne in mind that this depends much on the 
 temperature. If the solutions are kept boiling, a medal 
 may be made in a few hours. A single-cell apparatus 
 can be readily treated thus ; contrivances may easily be 
 devised for applying the heat from a furnace or a spirit- 
 lamp. In severe weather, the action of the battery 
 almost ceases. During the severe winter of 1840-41, 
 
VOLTAIC APPARATUS TO BE USED. 
 
 51 
 
 from November to March, my batteries were placed 
 within a few yards of the fire. 
 
 59. The advantages derived from the introduction of 
 a decomposition cell are not limited to the production of 
 single copies. Two or more may be made without any 
 further consumption of material in the battery. If, for 
 instance, two cells be placed side by side, and the plate 
 of copper (§ 56) be placed in one, and the mould (§ 56) 
 in the other : then, if the two cells be connected by 
 means of a bent copper wire, dipping into the liquid of 
 each, a circuit will be completed for the passage of the 
 voltaic current. In one cell, the copper plate will be 
 dissolved as before (§ 58), and copper will be deposited 
 on one end of the bent wire : in the other cell, the end 
 of that wire will be dissolved, and copper will be de- 
 posited on the mould. If the bent wire is removed, and 
 a mould is fixed (§ 31), on one end of it to receive the 
 copper released in the first cell, and a plate of copper* 
 on the other end to furnish a supply in the second cell, 
 the one action of the battery will produce two medals. 
 
 60. This mode of proceeding is not confined to tak- 
 ing merely two copies at a time; it may be extended 
 much further by using more cells. Experience has 
 taught me that six is a very convenient number. The 
 cells are to be connected, each to each, by bent wires, 
 
 * Soldering is not necessary for this purpose ; let a hole be 
 punched in the copper, and the wire be passed through and 
 twisted. It is then as well to varnish the wire (g 31) to pro- 
 tect it. Wires may be united by binding screws, cleft sticks, 
 or twisting. Mk 
 
52 
 
 ELECTROTYPE MANIPULATION. 
 
 having a mould on one end and a piece of copper on the 
 other. In proportion to the number of cells used, the 
 strength of the solution (§ 57) in them must be reduced 
 by adding water, and its conductibiliiy increased by 
 adding acid. It is desirable to place the moulds and 
 the sheets of copper as near together as possible, taking 
 care that they do not touch. A single pair of copper 
 and zinc in the battery or generating cell (§ 56) will thus 
 produce a series of six medals in three days, if the tem- 
 perature is not much below sixty. 
 
 61. They who possess the earthenware troughs be- 
 longing to the Wollaston battery will find the cells, on 
 account of their shape, very convenient for this purpose. 
 These troughs commonly contain twelve cells. The 
 shape of these cells permits the moulds and copper 
 plates to be placed face to face, which, with other pre- 
 cautions, insures an even deposit, and near to each 
 other, which shortens the length of liquid to be passed 
 through, and thus facilitates the operation. Troughs, 
 for this purpose, may be made in well-varnished wood, 
 of various sizes, and be divided into cells by means of 
 plate glass or glazed porcelain partitions.* 
 
 62. The advantage of this mode, in point of economy, 
 will be manifest, when it is remembered that for every 
 ounce of copper released from the solution in the gene- 
 
 * Gutta percha is very valuable for forming cells ; they are 
 not costly, and possess many advantages. Mr. Forster's pro- 
 cess of uniting gutta percha with wood for vessels of capacity, 
 will be found useful for large cells. 
 
VOLTAIC APPARATUS TO BE USED. 
 
 53 
 
 rating cell, an ounce will be deposited on each mould 
 (page 25); and about an ounce of zinc will be consumed 
 in effecting this. Whether, therefore, one (§ 56), or 
 six (§ 60), or even twenty moulds be placed in series, 
 the same quantity of zinc will be required. Hence an 
 ounce of zinc may be made to furnish electricity enough 
 to produce, according to the will of the experimenter, 
 one, or six, or more medals, each weighing an ounce. 
 
 63. Battery Apparatus extended. — Fig. 7 is an en- 
 graving of a DanielFs battery, thus connected with a 
 series of six cells, in each of which is a mould. A, the 
 battery ; B, the trough ; wire connecting copper plate 
 
 Fig. 7. 
 
 m 
 
 A 
 
 a cr, cl cf. a \ 
 
 0 
 
 % 
 
 
 % 
 
 
 
 C with the copper (§ 4) plate of the battery; x, wire 
 connecting mould m with the zinc of battery; a, a, a, 
 a, a, five bent wires, each having a mould at one end 
 and a piece of copper at the other (§ 31). A little 
 management is requisite in charging this, in order to 
 preserve the bright surface (§ 51) of the medals pro- 
 
 5* 
 
54 
 
 ELECTROTYPE MANIPULATION. 
 
 duced. Charge the battery as elsewhere directed; con- 
 nect the copper plate C with the battery; place a wire 
 with its extreme ends dipping in the extreme cells of the 
 trough ; then, having previously connected the zinc and 
 mould with the wire x } place the zinc in the porous cell 
 and the mould in its place at m ; in about two minutes, 
 it will be covered with copper; after this, there is no 
 fear of chemical (§ 60) action; then remove the end of 
 the copper wire from the cell containing m, and place it 
 in the next cell ; complete the circuit with the bent wire 
 a, having a mould at one end, and a sheet of copper at 
 the other; after waiting a minute or two for a deposit 
 of copper, remove the end of the wire one cell further 
 forward ; and so continue till the six moulds are placed 
 in. 
 
 64. I have been in the habit of rendering the elec- 
 trotype art available in the production of the very ap- 
 paratus which is destined to be employed in the art; 
 and have produced a compact, neat, and very simple 
 lattery , by the same process by which the battery thus 
 formed will produce copies of medals. I take a large 
 jelly-pot, and, placing within it some wax, stand it by 
 the fire till the wax is melted and the vessel thoroughly 
 heated ; then turn it about, so that the wax shall spread 
 over every part of the interior; and, having done this, 
 pour away the superfluous wax. When cold, I rub 
 plumbago, in the manner formerly described (§ 38), over 
 the wax adhering to the sides. This vessel is then filled 
 with a saturated acid solution of sulphate of copper, and 
 in it is placed a porous tube ; the tube is filled with acid 
 
VOLTAIC APPARATUS TO BE USED. 55 
 
 water; a piece of amalgamated zinc is placed in the tube; 
 the wire attached to it is bent over, and made to press 
 upon the surface of the plumbago. In two or three 
 hours, the whole of the interior where the plumbago is 
 will be covered with metallic copper. The vessel will 
 now form one of the best and simplest generating or 
 battery cells that can be constructed : this deposition of 
 copper forms the copper plate (§ 3) of the voltaic pair. 
 The plaster diaphragm (§ 49) and the solutions will 
 complete the apparatus. Or the whole of the interior 
 surface might be covered with plumbago; and when, 
 after having been used for a week or two, the deposited 
 copper should become thick enough, it might be drawn 
 out, or the earthenware cell might be broken from it, 
 and thus a complete cell of a Daniell's battery (§56) 
 might be obtained without a seam or joint. To connect 
 a wire with this coating, it is only necessary to brighten 
 the end, and bend it so that it shall press closely. 
 
 65. Smee's Battery. — This very useful source of vol- 
 # taic power was named by its inventor, the Gliemico-me- 
 chanical Battery. It requires but one liquid for excit- 
 ing it, namely, acid water ; the metals are amalgamated 
 zinc and platinized silver ; that is, silver on which mole- 
 cules of platinum have been voltaically deposited in the 
 form of a black powder. A small quantity of the bi- 
 chloride of platinum is mixed with acid water, and the 
 solution is decomposed by the use of a platinum terminal 
 in connection with the copper of the battery, and the 
 substance to be platinized in connection with the zinc, 
 A few minutes' action will suffice. Platinum is some- 
 
56 
 
 ELECTROTYPE MANIPULATION. 
 
 times platinized; but, for all practical purposes, silver 
 is equally serviceable. This aggregation of small points 
 facilitates the liberation of the evolved hydrogen, which 
 escapes with a loud hissing noise, in place of adhering 
 to the metal and interrupting the action. The arrange- 
 ment is generally made with one platinized silver plate 
 between two zinc plates, as in the following figure, where 
 s is the silver plate connected with the copper of the 
 usual decomposition cell, and z the zinc plate connected 
 with the moulds. In employing this arrangement, care 
 must be taken to avoid dropping any sulphate of copper 
 into the acid water ; for the copper would at once be 
 reduced upon the silver plate, and by altering the nature 
 of the battery would spoil it. 
 
 66. As the silver plate in this arrangement is between 
 the zinc plates, it follows that the streams of hydrogen 
 must ascend between the metals of the pair, so that, 
 while in one sense they form a partial screen between 
 the plates, they, on the other hand, prevent the plates 
 
VOLTAIC APPARATUS TO BE USED. 57 
 
 being approximated within certain limits. A very in- 
 genious modification of this arrangement has been 
 devised by Professor Grove,* who substitutes platinized 
 silver gauze in place of the plate of silver ; as, by this 
 means, a facility is afforded to the hydrogen of passing 
 through the apertures of the gauze, and making its 
 escape at the outer side instead of between the two 
 plates, the latter may be brought much closer together, 
 without having the action intercepted by the presence 
 of the liberated and escaping hydrogen. 
 
 67. New Electrotype Battery. — As it is no easy 
 matter to obtain silver gauze, I advise the following 
 substitute, which has its peculiar advantages : Take a 
 sheet of cleaned (§ 98) copper gauze, of the exact size 
 required (for it must not be cut afterwards), and affix 
 to it permanently the binding screw or wire, which is to 
 be employed afterwards in making connections. Place 
 it then in a decomposition cell, containing sulphate of 
 copper, and submit each side to the action of the bat- 
 tery, until a bright deposit of pure copper is thrown 
 down, of sufficient thickness to coat all the wires, and 
 to unite them permanently into one. Then remove and 
 wash it in boiling water. After which, electro-plate it 
 by the means to be described in Part II. A piece of 
 copper gauze, thus prepared, will be even better fitted 
 for the desired purpose, than if it were of silver wire ; 
 for the deposition of copper on it, and then plating this 
 deposit, will have advanced one great step towards 
 
 * Vide Proceed. Elec. Soc. p. 117.— Sept. 21, 1841. 
 
58 
 
 ELECTROTYPE MANIPULATION. 
 
 altering the character of the surface; and producing 
 one better fitted to throw off the hydrogen. The opera- 
 tion will be completed by platinizing according to the 
 directions given above. 
 
 68. In the illustration of the platinized battery 
 (§ 65), the metals are represented parallel and per- 
 pendicular ; in the present arrangement there must be 
 but one zinc plate, and the zinc and gauze must be 
 very near to each other, but must deviate a few degrees 
 from the perpendicular ; and in such a direction that 
 the platinized gauze shall be, as it were, uppermost. 
 For, as the gas finds its way to the surface in perpen- 
 dicular lines, such a disposition of the arrangement 
 will at once admit it to pass through the interstices of 
 the gauze, and readily to escape by the desired channel 
 — the outside of the gauze. A better mode of con- 
 structing the apparatus is to employ a gauze on each 
 side of the zinc. In this case, the zinc must be perpen- 
 dicular • and the gauze not exactly parallel, but rather 
 closer at the top than below. The difficulty of obtain- 
 ing copper gauze led to the production of electro-lace, 
 which was first suggested and made for this kind of 
 battery by Mr. Phillips of St. Austell. 
 
 69. Electro-Lace. — A piece of lace is stretched on a 
 frame, and well rubbed with warm wax : it is then held 
 to the fire to effect its saturation with wax, and is 
 placed afterwards, and while hot, between two pieces of 
 blotting paper in order to remove the wax from the pat- 
 tern ; or it may be saturated with varnish. It is then 
 plumbagoed and treated as an ordinary mould. A few 
 
VOLTAIC APPARATUS TO BE USED. 59 
 
 hours' action will so deposit metal on it as to present 
 the character of a perfect conversion into copper. This 
 may be plated, and then platinized. 
 
 70. Constant Acid Battery. — Since the appearance 
 of the first edition of this work, I have been employ- 
 ing, with slight modification, an ordinary acid battery, 
 namely, a chemico-mechanical battery, in which rough- 
 ened copper is used instead of platinized silver ; and I 
 find it admirably adapted to the purpose of electrotype. 
 Other circumstances being the same, it requires nearly 
 twice the time of a sulphate battery ; but this is in a 
 degree compensated by the fineness of the deposit ob- 
 tained, and the trifling expense attending its use. — The 
 interior of a jar is coated with copper (§ 67), and the 
 action is continued until the solution employed for this 
 purpose is nearly exhausted. By this means, the sur- 
 face of the copper obtained presents an infinite number 
 of small points, which very readily part with the hydro- 
 gen. The principle is precisely that developed by Mr. 
 Smee, and brought to practice in his platinized battery. 
 — This arrangement may be adopted without the use of 
 diaphragms. Amalgamated zinc is employed. I find 
 that this kind of battery, variously arranged, is greatly 
 used in the arts. Sometimes a single battery is suffi- 
 cient; at other times, a series of two, three, or four, 
 having the zinc of one connected with the copper of the 
 next; as in Fig. 9. — I have myself been of late operating 
 with this battery on a large scale, using surfaces of from 
 10 to 14 square feet : if the copper surface has been 
 exposed to the air for any time, while the battery is out 
 
60 
 
 ELECTROTYPE MANIPULATION. 
 
 of use, it should be well washed with acid water, or the 
 old solution of zinc, before using it again, in order to 
 remove any oxide of copper that may be there. Under 
 
 these circumstances, I have every reason to be satisfied 
 with its action, and to prefer it, from its simplicity and 
 steady action, to any other form. 
 
 71. Prince Bagration's Battery. — A pan is filled 
 with earth, which is then saturated with a solution of 
 sal-ammoniac ; a copper plate, having been first wetted 
 with solution of sal-ammoniac, and then exposed to the 
 air until a green film is formed, is thrust into the pan of 
 earth ; and opposite to it is thrust a zinc plate. Prof. 
 Jacobi speaks favorably of this source of a constant 
 power for the reduction of metals. 
 
 72. The Earth a Battery. - — When slow actions are 
 required, the moisture of the earth itself may be made 
 
VOLTAIC APPARATUS TO BE USED. 
 
 61 
 
 a source of power ; all that is necessary being to bury 
 in it large plates of zinc and copper. The native moist- 
 ure of the soil constitutes the exciting liquid. 
 
 73. Decomposition Cells may be constructed of all 
 sizes, according to circumstances, of wood, protected 
 with varnish, or other compounds impervious to water. 
 Two parallel wires are secured along the top ; one is to 
 be connected with the zinc, and the other with the cop- 
 per of the battery. On the former are hung the moulds, 
 by merely bending the wires attached to them into a 
 hook ; and on the latter is hung a sheet of copper. These 
 wires may be placed nearer to each other, as circum- 
 stances require. By this means, several medals may be 
 made at the same time. This arrangement is most 
 commonly adopted; it does not of course economize the 
 zinc, as described in a former place (§ 62). One ounce 
 of zinc produces six or more medals, not weighing each, 
 but all together an ounce. 
 
 74. The deposited metal will present various thick- 
 nesses, according to the relative position of the mould 
 and the plate of copper; if they are face to face, and 
 parallel, the thickness will be uniform, or nearly so; 
 generally speaking, the copper on the lower part of the 
 mould is thicker than that on the higher : this occurs 
 from the specific gravity of the sulphuric acid, used to 
 render the liquid conductible, determining it in a mea- 
 sure toward the bottom of the cell, rendering the lower 
 part of the liquid more conductible than the upper. To 
 cause a more uniform distribution, it is better to stir the 
 liquid occasionally. But in many cases it is advisable 
 
 6 
 
62 
 
 ELECTROTYPE MANIPULATION. 
 
 to have a flat trough, as in the annexed sketch, and to 
 place the mould below and the copper plate above. With 
 large casts, and those in deep relief, this is absolutely 
 
 Fig. 10. 
 
 necessary; for without it a uniform thickness in the de- 
 posit is next to impossible, and the solution within the 
 recesses of the mould, being unable to ascend and inter- 
 change itself with the rest, as it becomes exhausted of 
 metal, soon gives a brittle deposit, and finally no de- 
 posit at all. My largest trough, which will contain 
 upwards of a hundred gallons of solution, is of this 
 form, and is lined with a mixture of asphalte and rosin. 
 Mechanical arrangements keep the mould sunk, until the 
 deposited metal is itself heavy enough for the purpose. 
 The copper plate is removed once or twice a day and 
 washed, to prevent defiling the cast with the impurities 
 of the metal. 
 
 In order to hasten the thickening of the deposit, 
 Professor Jacobi has recommended that copper filings 
 be occasionally sifted upon the electrotype; and when 
 one batch of filings have become incorporated with the 
 
MANAGEMENT OF MOULDS. 
 
 63 
 
 solid metal, by means of the reduced copper, he advises 
 other siftings to be made : and so on. 
 
 75. Management of the Moulds. — Thus much, then, 
 with respect to the construction of moulds, and the nature 
 and various forms of the voltaic apparatus. From what 
 has been said, the reader will be able to make his own 
 selection, according to circumstances; he will see the 
 capabilities of the several processes, and adopt the one 
 best suited to his particular purpose. It remains now to 
 give a few special directions in reference to the manage- 
 ment of moulds, and of the voltaic apparatus generally. 
 The copper solution will act chemically on the fusible 
 metal, if the mould is placed in it before the battery is 
 in action, and will produce on its surface a dirty, dark 
 deposit. To guard against this, it is necessary that 
 everything should be arranged before the mould is placed 
 in the situation allotted to it (§ 51). The circuit should 
 be completed by immersing the mould last. With this 
 precaution, the immersion of the mould, if of metal, will 
 be followed by an instant deposit of copper on its whole 
 surface ; after which there is no fear of the oxide. A 
 circumstance no less strange than true in these experi- 
 ments, is, that the surface of a fusible mould thus man- 
 aged is never wetted by the liquid in which it is placed ; 
 in fact, it never comes into actual contact with the liquid ; 
 its immersion in the liquid and its receiving a coating 
 of copper are simultaneous ; the one is the instantane- 
 ous cause of the other. When the copy is removed, the 
 mould is as bright and as dry as when first made. 
 
 76. The deposition of the copper on the plumbagoed 
 
64 
 
 ELECTROTYPE MANIPULATION. 
 
 surface (§ 39) of the wax moulds, is not thus instantane- 
 ous. The film of conducting substance with which they 
 are coated being very thin, and not continuous, the ope- 
 ration is a step by step process from particle to particle. 
 The deposition of copper is gradual: it commences in 
 the neighborhood of the wire attached to them, and 
 spreads gradually over the remaining portion. These 
 moulds do become wetted, and the medals obtained from 
 them often come off with dirty surfaces ; the medals also 
 bring with them the whole or part of the plumbago, and 
 hence the moulds, if not damaged, require a fresh coat 
 of this, before they are used again. These dirty speci- 
 mens may be very readily cleaned, if required ; the mode 
 will be described in the sequel. The production of dirty 
 medals is the least evil arising from the use of plumba- 
 goed moulds ; there is one of far greater importance — 
 one which requires some attention to escape. As the 
 deposition of copper, which is gradually diffused over the 
 whole surface, commences at one point contiguous to the 
 connecting wire, it follows that the power of the battery 
 at the first is concentrated in a small space. The con- 
 sequence of this will be, that, unless means be taken to 
 avert it, hydrogen will be evolved with the copper at 
 first, decreasing in quantity till enough of the mould is 
 covered with a film of copper to increase the size of the 
 surface to the requisite standard for releasing copper alone, 
 after this all things go on well ; but it is invariably 
 found that the portion near the wire, from the irregu- 
 larity of the primitive deposit, is rotten or very brittle. 
 To prevent this, I always begin by placing a wire in lieu 
 
MANAGEMENT OF APPARATUS. 
 
 65 
 
 of a plate, opposite the plumbagoed mould, in the de- 
 composition cell ; this reduces the power of the battery 
 or the quantity of electricity passing : as the copper 
 deposits, I immerse the wire to a greater depth, and 
 when the mould is partially covered with copper, I re- 
 move the wire, place in the copper plate, and leave the 
 experiment with the assurance of a successful result. 
 But moulds furnished with guiding-wires (§ 39) may 
 be put into the decomposition cell without the precau- 
 tion of using a wire first, instead of a plate, as above 
 suggested. It will occasionally occur in wax moulds, 
 and sometimes in fusible metal moulds of very elabo- 
 rately executed medals, that bubbles of air remain in some 
 of the complicated interstices; these must be removed, 
 or the result will be infallibly disfigured. They are re- 
 moved by lightly brushing the surface of the mould with 
 a feather, immediately after it is immersed in the liquid. 
 If it should seem that any part of the mould is not suffi- 
 ciently coated with plumbago, it may be removed from 
 the solution, washed with water, dried with blotting- 
 paper, and again rubbed with plumbago. This will 
 sometimes save it, although generally such a condition 
 of things announces a failure. 
 
 77. Management of the Battery Apparatus. — The 
 electrotypist, who expects to find all his experiments 
 going on favorably, will be often grievously disappointed : 
 with the best intentions and the most careful arrange- 
 ments he may sometimes fail. For, after having observed 
 all the directions hitherto given, his battery may have 
 too little work to do, or too much; and this can only be 
 
 6* 
 
66 
 
 ELECTROTYPE MANIPULATION. 
 
 determined by experience, and by attention to the prin- 
 ciples laid down in this book. The former will produce 
 the dark powder, elsewhere mentioned (76); the latter 
 a hard, red, brittle deposit, or a heap of crystals. The 
 terms too much and too little are here used in a very 
 general sense, and. will be better understood by describ- 
 ing the causes, the results, and the mode of rectifying 
 these irregularities. 
 
 78. If the battery is too large, or the copper plate in 
 the decomposition cell is too large; or if the mould is 
 too small, hydrogen as well as copper will be released, 
 and the deposit will be the dark powder ; the same 
 will occur if the solution in the decomposition cell con- 
 tains too mrach acid or too little sulphate of copper. To 
 rectify this, the battery may be made smaller by pour- 
 ing out some of the solution, and so exciting less of its 
 surface ; or a smaller copper plate may be used in the 
 decomposition cell ; or crystals of sulphate of copper 
 may be thrown into the liquid contained therein ; or 
 the copper plate and mould may be removed far apart ; 
 or a fine wire may be interposed between the mould and 
 the wire connecting it with the battery. Each or all of 
 these alterations may be made according as circum- 
 stances or convenience shall dictate ; a few days' expe- 
 rience will be better than pages of instruction. 
 
 79. If the battery is too small, or the copper plate in 
 the decomposition cell too small ; or if the mould is too 
 large, or if the decomposition cell contains too little acid 
 or too much sulphate of copper, or if the weather be too 
 cold, the copper will be deposited very slowly, and will 
 
MANAGEMENT OF APPARATUS. 
 
 67 
 
 present a dull red exterior, and be of a very brittle tex- 
 ture ; or will be thrown down in a crystalline form. 
 The alterations necessary to rectify this defect will 
 readily suggest themselves. 
 
 80. The medium between these two conditions for- 
 tunately has a very wide range, so that the chances of 
 avoiding the two extremes are greatly in favor of the 
 experimenter. The lines of demarcation within which 
 the proper deposit is obtained, are, as may be imagined, 
 not precisely denned. And hence the deposited metal 
 possesses various gradations of character, according to 
 the circumstances under which it is obtained. When 
 all things are going on well, if the mould be lifted out* 
 of the solution, it will present a brilliant, light, copper- 
 colored surface : this characteristic can scarcely be mis- 
 taken after it is once seen. 
 
 81. In addition to this, the following general ob- 
 servations on the theory of deposits, may be ac- 
 ceptable : "It was thought that the rotten deposit 
 —a characteristic with which all those who are but just 
 initiated into the art are familiar — results from the 
 presence of the sulphate of zinc among the sulphate of 
 copper . . . The real cause depends on the relation 
 subsisting between the generating power, dependent on 
 the action between the zinc and the acid, and the 
 strength of the solution of the sulphate of copper, on 
 which this power is exercised. If the latter is well 
 
 * The mould may be removed with impunity, after it is well 
 coated with metal. 
 
68 
 
 ELECTROTYPE MANIPULATION. 
 
 saturated, the copper will be released pure and firm ; if 
 it is almost exhausted, the hydrogen gas will be released 
 with the copper, and the deposit will be a dull powder. 
 In the wide range between these two states is found the 
 brittle deposit : it appears under many varieties of 
 forms, according as. the solution is nearer to a state of 
 saturation or to one of exhaustion on the one hand ; or 
 according to the energy or weakness of the affinity be- 
 tween the zinc and its exciting solution on the other. 
 This latter condition exists in a modified form, when a 
 large piece of zinc is used with a small object to be 
 copied. The deposit is very hard, but not tenacious. 
 It may be easily broken. In copying seals, and such 
 like small objects, little pieces of zinc an inch square 
 are quite large enough." 
 
 82. The medals are removed from the fusible moulds 
 by gradually raising the edges with a pointed instru- 
 ment, a brad-awl, for instance, and then using it lever- 
 fashion to raise the medal out of the mould. Care must 
 be exercised in this, for the contact between the two is 
 so close that the force occasionally required may cut 
 the medallion. The separation from the wax-moulds 
 requires no force, they are laid face downwards on a 
 table, and after pressing the slight overlapping edge of 
 copper with the brad-awl, in different parts of the cir- 
 cumference, the two may be pulled apart. 
 
BRONZING. 
 
 G9 
 
 IV.—BKONZING. 
 
 83. If proper precautions are taken, the medals from 
 the fusible moulds will generally present a bright copper 
 surface ; occasionally, however, they will present a very 
 brilliant surface, greatly resembling silver. When this 
 is the case they may be placed, without further trouble, 
 for the cabinet. The silvery tint is only obtained on 
 first specimens : it would seem that the surface of the 
 new-made mould is covered with a metallic film, which 
 attaches itself firmly to the surface of the deposited cop- 
 per. It is so firmly attached, that it may be polished 
 with a leather or plate brush, without sensibly affecting 
 it. If specimens of this description are exposed to the 
 air, they will occasionally require the application of the 
 plate-brush to restore their primitive brilliancy. 
 
 84. Chemical Bronze. — There are many modes of 
 bronzing employed in the arts ; the intent of each is to 
 bring out the workmanship of the object. The selection 
 is entirely a matter of taste. To prevent too great a 
 sameness of appearance in a cabinet, it is perhaps better 
 not to confine one's self to a solitary method. — A chemi- 
 cal bronze may be made by boiling two ounces of car- 
 bonate of ammonia with one ounce of acetate of copper 
 in half a pint of vinegar, till the vinegar is nearly evap- 
 orated. Into this, pour a solution consisting of sixty- 
 two grains of muriate of ammonia, and fifteen grains 
 and a half of oxalic acid, in half a pint of vinegar. 
 Replace the vessel on the fire till the contents boil : 
 
70 
 
 ELECTROTYPE MANIPULATION. 
 
 when cold, strain through filtering paper ; preserve the 
 liquor for use. The remaining sediment may be again 
 treated with another half pint of the solution. This 
 preparation must only be applied to medals perfectly 
 bright and clean. 
 
 85. Dirty specimens may be polished by an article 
 used in domestic economy, consisting of rotten-stone, 
 soft soap, and water; the medal is to be well rubbed 
 with a hard brush dipped in this. Care must be taken 
 not to scratch the medal. It must afterwards be wash- 
 ed in water and placed to dry ; when dry, the applica- 
 tion of the leather and plate brush will produce the re- 
 quired polish. Medals may also be cleaned by dipping 
 them for a few seconds in nitric acid, either concen- 
 trated or diluted; wax and grease may be removed by 
 boiling in pearlash and water, or by pouring the boil- 
 ing lye on the medals ; or by washing with turpentine. 
 Cleansing processes will be more fully described in the 
 Second Part, when we come to electro-gilding and 
 plating, in which they are of prime importance. 
 
 86. In applying the bronze, first warm the medal, 
 then dip a earner s-hair pencil into the liquor (§ 84), 
 and brush the surface for half a minute ; immediately 
 after, pour boiling water over it ; directly the medal is 
 dry, rub its surface lightly with soft cotton, very 
 slightly moistened in linseed oil : gentle friction with a 
 piece of dry cotton will finish the operation. The color 
 produced by this means, is red ; its tint varies accord- 
 ing to circumstances. Medals bronzed thus must be 
 examined occasionally before they are consigned to the 
 
BRONZING. 
 
 71 
 
 cabinet ; for if perchance the vinegar has not been per- 
 fectly washed away, they will be disfigured by the forma- 
 tion of a green powder — the acetate of copper. Should 
 this occur, it may be removed by means of the moist 
 and dry cotton. 
 
 87. Black-Lead Bronze. — A very beautiful bronze is 
 obtained by the simple application of plumbago ; it is 
 obtained in a few minutes, and with very little trouble. 
 The tint obtained seems very much to depend on the 
 condition of the surface of the original medal ; copies 
 of some medals " take " the black-lead better than those 
 of others. To produce the tint in the greatest perfec- 
 tion, the operation should be performed immediately 
 after the medal is separated from the mould. Briglit 
 specimens from fusible moulds are best, but all others 
 may be thus treated ; those taken from wax should be 
 cleaned with pearlash or soda. 
 
 88. The bronze is obtained by brushing the surface 
 of the medal with plumbago ; then placing it on a 
 clear fire till it is made too hot to be touched, and 
 applying a plate-brush as soon as it ceases to be hot 
 enough to burn the brush. A few strokes of the brush 
 will produce a dark brown polish, approaching black, 
 but entirely distinct from the well-known appearance of 
 black-lead. If the same operation is performed on a 
 medal that has been kept some days, or upon one that 
 has been polished (§ 85), a different but very brilliant 
 tint is produced. The color is between red and brown. 
 The richness of color thus produced is by many pre- 
 ferred to the true dark brown. 
 
72 
 
 ELECTROTYPE MANIPULATION. 
 
 89. Carbonate of Iron Bronze. — Very beautiful tints 
 are produced by using the substance commonly known 
 as plate-powder, or rouge ; after moistening it with 
 water it is applied and treated precisely in the same 
 manner as the plumbago. Some care and practice are 
 required in its use, lest it should stain instead of bronze 
 the medal. — I have received from the publishers of 
 this book a specimen of bronze superior to any I have 
 elsewhere met with. It leaves nothing to be desired. 
 
 ■ — Should an experiment fail, the several bronzes may, 
 in many cases, be removed, and the attempt can be 
 repeated. 
 
 90. Mounting the Medals. — I have adopted a method 
 of mounting the medals obtained from the fusible 
 moulds (§ 20), which gives a finish to their appearance. 
 I obtain pale green cards, the size of visiting cards ; 
 and cut some of these into single squares ; the width of 
 the card being the side of the square ; others into 
 smaller squares, half the length of the card forming the 
 side of the square. A pencil circle is drawn the size of 
 the medal; and two ink circles in order to " throw' ' 
 the medal " forward." The part within the pencil 
 circle is cut out ; and waste cards are cut to fit the extra 
 edge of the medal. The two cards being fixed together 
 with very strong gum water, the medal is placed in, 
 and secured by another card gummed on at the back. 
 The obverse and reverse are then gummed back to back, 
 and thus the appearance of a perfect and solid medal is 
 produced, equal, in point of workmanship and beauty, 
 to the original. To hold the cards together until the 
 
CONCLUDING OBSERVATIONS. 
 
 73 
 
 gum dries, I use cleft-sticks. The medals obtained from 
 wax moulds, having no addition to the edges, are not 
 well fitted to be mounted thus : they may simply have 
 any roughness removed from their edges with a sharp 
 file, and be placed in the cabinet without being fitted 
 with cards. 
 
 V.— CONCLUDING OBSERVATIONS. 
 
 91. Having now gone systematically through the 
 process of working in copper, by means of the voltaic 
 current, halting here and stepping aside there, in order 
 to make all things as clear as possible; and having 
 fulfilled my promise (§ 1) of leading the reader " from 
 the original medal to the perfect copy, ready for the 
 cabinet f f I trust he is in a condition, so far as these 
 instructions are concerned, to go from small things to 
 great, and by increasing the size of his apparatus, as 
 it shall seem good to him, to carry out on the large 
 scale what he has here been taught to do on the small. 
 I now, therefore, refer him to Part II., in which the 
 manipulation with gold and silver, and other metals 
 and alloys of metals, will be detailed ; and all and sun- 
 dry the leading applications and the extensive ramifica- 
 tions of the art will be set before him. 
 
 7 
 
INDEX. 
 
 Acid battery, constant, \ 70. 
 Affinity, elective, electro-chemical, \ 4. 
 Air-bubbles to be removed, g 76. 
 Amalgamation of zinc, $ 46. 
 
 Battery for works on a large scale, \ 70. 
 
 Prince Bagration's, § 71. 
 
 produced by the electrotype process, \ 70. 
 
 the earth as a, \ 72. 
 
 too large, \ 78. 
 
 too small, \ 79. 
 
 without acid or mercury, \ 53. 
 
 Black-lead for wax moulds, § 37. 
 Brittle copper, mode of avoiding, $ 77. 
 Bronze, carbonate of iron, \ 89. 
 
 Knight's, \ 89. 
 
 chemical, § 84. 
 
 application of, \ 86. 
 
 plumbago, § 87. 
 
 Charcoal, or carbon, for negative plate, \ 5. 
 Chemical action, ordinary, cause of, \ 46. 
 Chemical effects, ordinary, \\ 7, 18. 
 Chemico-mechanical battery, \ 65. 
 Cleaning electrotype medals, \ 85. 
 
7G 
 
 INDEX. 
 
 Clichee moulds, § 26. 
 Constant battery, H 18, 56, &c. 
 
 Copper in good condition, chances in favor of depositing, \ 80. 
 irregularity in the deposition of, \ 74. 
 
 Daniell's constant battery, \\ 18, 56. 
 Decomposition cell, \\ 43, 73. 
 flat, I 74. 
 
 introduction of, for electrotype, g 56. 
 
 of sulphate of copper, \\ 12, 13. 
 
 of water, g 11. 
 
 Diaphragms, brown paper, § 44. 
 
 membrane, \ 48. 
 
 pipe-clay, \ 48. 
 
 plaster of Paris, \ 49. 
 
 Elastic moulds, \ 42. 
 
 Electrical equilibrium, disturbance of the, \ 6. 
 Electro-chemical equivalents, page 14, \ 51. 
 Electro-lace, § 69. 
 Electrolysis, description of, § 10. 
 Electrotype, § 14. 
 
 facility of practising, \ 15. 
 
 minutely correct in copying, \ 24. 
 
 Filings for thickening casts, § 74. 
 Flame from charcoal points, page 23. 
 Flowers, mode of copying, $ 39. 
 Fused compounds decomposed, page 24. 
 Fusible metal for smaller medals, §21. 
 ingredients in, \ 22. 
 
 Gauze for battery plate, \ 66. 
 Generating cell, § 43. 
 Glass, how to coat, g 41. 
 
INDEX. 
 
 77 
 
 Glauber's salt to give conducting power, \ 37. 
 Guiding-wires, \\ 39, 76. 
 Gutta Percha moulds, \ 42. 
 
 Heating power of batteries, page 24. 
 Hydrogen released at the copper plates, $ 4. 
 released with the copper, § 78. 
 
 Insects, mode of copying, \ 39. 
 
 Iodide of potassium, decomposition of, page 24. 
 
 Medals to be cold for use, \ 24. 
 
 Metals released at negative end of voltaic pairs, \ 14. 
 Moulds, elastic, \ 42. 
 
 gutta percha, \ 42. 
 
 made in parts, \ 41. 
 
 management of, \ 75. 
 
 of fusible metal not wetted by the liquid, g 75. 
 
 preparation of, page 26. 
 
 Mounting electrotype medals, mode of, $ 90. . 
 Muriate of ammonia for batteries, | 53. 
 
 Names given to the art of copying by voltaic electricity, \ 2. 
 Negative end of the battery, which is the, \ 8. 
 
 Oxygen released at the positive plate, \ 4. 
 
 Phosphorous solution for flowers, &c, § 39. 
 Physiological effects of Voltaic electricity, page 23. 
 Plaster-casts, facility of obtaining, \ 34. 
 
 wax moulds from, $ 35. 
 
 diaphragms, moulds for, \ 49. 
 
 of Paris, manipulation with, \ 40. 
 
 moulds, § 40. 
 
 7* 
 
78 INDEX. 
 
 Plaster of Paris, to be used fresh, \ 49. 
 
 removed from wax, \ 36. 
 
 Platinized silver, § 65. 
 Platinum terminal wires, $ 13. 
 
 Pliable copper, directions for the production of, \\ 58, 77. 
 Positive end of the battery, which is the, § 8. 
 Plumbago, adulteration of, \ 38. 
 
 for wax moulds, \ 38. 
 
 mode of application to wax, \ 39. 
 
 Removing medals from moulds, \ 82. 
 
 Saucers for fusible moulds, § 25. 
 
 Seals, mode of copying, \ 55. 
 
 Series of moulds, deposition on a, \\ 60, 63. 
 
 Silver for a conducting surface, § 39. 
 
 Silvery surface, production of, \ 83. 
 
 Single cell apparatus, \ 51. 
 
 Smee's battery, § 65. 
 
 Soldering, \ 55. 
 
 Solutions, \ 57. 
 
 Stearine for moulds, \ 33. 
 
 Tallow, use of, for saturating plaster of Paris, \ 40. 
 Temperature of apparatus, § 58. 
 Theory of deposits, general observations on the, \ 81. 
 Time to produce electrotype copies, \ 58. 
 Troughs for a series of moulds, g 63. 
 
 Varnish for fusible moulds, \ 31. 
 Voltaic apparatus for electrotype, page 39. 
 Voltaic current, direction of the, illustrated, \ 9. 
 Voltaic current, great effects of, $ 10. 
 illustrated, § 4. 
 
INDEX. 
 
 Water battery, page 24. 
 
 Water, chemical composition of\ $ 4. 
 
 Wax moulds, | 32. 
 
 cautions concerning, $ 76. 
 
 removing from medals, | 32. 
 
 rendered conductible, \ 37. 
 
 used for copying larger medals, $ 21. 
 
 Wire, attaching to fusible moulds, § 31. 
 
 wax moulds, \ 39. 
 
 Wood for porous diaphragms, \ 53. 
 
 Zinc and copper, a voltaic pair of, $ 3. 
 
 mode of amalgamating, $ 46. 
 
 Zinc, pure, \ 46. 
 
 END OF PART I. 
 
ELECTROTYPE MANIPULATION. 
 PART II. 
 
ELECTROTYPE MANIPULATION! 
 
 PART II. 
 
 CONTAINING 
 
 THE THEORY AND PLAIN INSTRUCTIONS 
 
 IN THE ARTS OF 
 
 ELECTRO-PLATING, ELECTRO-GILDING, AND ELECTRO-ETCHING; 
 
 WITH AN ACCOUNT OF 
 
 THE MODE OF DEPOSITING METALLIC OXIDES, 
 
 AND OF THE SEVERAL 
 
 APPLICATIONS OF ELECTROTYPE IN THE ARTS. 
 BY 
 
 CHARLES V. WALKER, 
 
 Honorary Secretary to the London Electrical Society ; Editor of the Electrical 
 Magazine, Kaemtz's Meteorology, etc. etc. 
 Telegraph Engineer, and Superintendent to the South-Eastern 
 Railway Company. 
 
 ILLUSTRATED BY WOOD-CUTS. 
 FROM THE TWENTY-FIFTH ENGLISH EDITION. 
 
 PHILADELPHIA: 
 HENRY CAREY BAIRD, 
 
 SUCCESSOR TO E. L. CAREY. 
 
 1852. 
 
PHILADELPHIA: 
 T. K. AND P. G. COLLINS, PRINTERS. 
 
CONTENTS. 
 
 I.— INTRODUCTORY OBSERVATIONS. 
 
 PAGE 
 
 Cyanide of Potassium . . . . .12 
 
 Silver Solution . . . . » .14 
 
 Oxide of Silver . . . „ . .14 
 
 Cyanide of Silver . . » . . .16 
 
 Preparation of the Gold Solution . . . .16 
 
 Single Cell for Plating and Gilding . . .17 
 
 Plating by means of a Single Cell . . .20 
 
 Gilding by means of a Single Cell . . .22 
 
 Battery Process for Plating and Gilding . . .23 
 
 Voltaic Condenser . . . . .24 
 
 Application of Heat . fc . . .26 
 
 Preparing Surfaces to unite with Gold and Silver . 28 
 
 Cleansing by the Dry Method . . . .29 
 
 Cleansing by the Wet Method . . . .29 
 
 Amalgamation to promote Adhesion . .. . 32 
 
 Cleaning Electro-Plate . . . . .34 
 
 Gilding-Wax . . . > . .34 
 
 Various Metallic Solutions . . . .35 
 
 Silvering-Liquor . . , , . .38 
 
 Gilding-Liqnor . . . » . .38 
 
 Coppering-Liquor . „ . . . .39 
 
 Other Applications of Electro-Gilding . . .40 
 
 Daguerreotype Plates . . . . .41 
 
 8 
 
CONTENTS. 
 
 PAGE 
 
 Electro-Zincing . . . . . .42 
 
 Reduction of Alloys . . . . .42 
 
 Electro-Tinning . . . . . .43 
 
 Electro-Brass . . . . . .43 
 
 Electrolysis of Fused Compounds . . .44 
 
 Magneto-Electro Machine - . \ ' . . .45 
 
 II.— DEPOSITION OF THE OXIDES OF METALS ON 
 METALS. . ."" ' ' 
 
 Metallo-Chromes . . .. .. / . 47 
 
 Deposition of Oxide of Lead . . ... . . 49 
 
 Deposition of Oxide .of Iron- . 50 
 
 . III. — ELECTRO-ETCHING. ' , 
 
 Process of Electro-Etching ;■>.:. . . . 52 
 
 Electro-Etching Daguerreotype .Plates .' . . 53 
 
 Nature of Daguerreotype Pictures . . . .54 
 
 M. Fizeau's Process. ., . .58 
 
 New -Mode of Etching < ..... . . 59 
 
 , IV. — APPLICATIONS OF ELECTROTYPE, &o. 
 
 Patents . - . . . . . . . . .60 
 
 Electro-Tint; or, Galvanography . . . .65 
 
 Glyphography . ■ .' . . . - . .66 
 
 Metallic Cloth ... . . . . . .67 
 
 Purity of Sulphuric .Acid . . . . .67 
 
 Test for Nitric in Sulphuric Acid . . . .68 
 
 Copying Busts, &c." • - • . • . . * 69 
 
■ 
 
 ELECTROTYPE MANIPULATION. 
 
 PART II. 
 
 I.— INTRODUCTORY OBSERVATIONS. 
 
 92. Having in Part I. given the mode of working 
 in copper, we pass on now to other metals. First in im- 
 portance come gold and silver. The earliest experiments 
 in electro-gilding were those by Brugnatelli, who gilded 
 silver medals by electricity, in 1805 ; he used a solution 
 of nitro-muriate of gold mixed with a solution of ammo- 
 nia. The next were those of De la Rive, in 1841, who 
 used a solution of chloride , of gold. But these pro- 
 cesses were interesting rather in a theoretical than in a 
 practical point of view ; inasmuch as the elective chemi- 
 cal affinity of the elements (combined in these solutions 
 with the gold) for the baser metals, which might be im- 
 mersed in the solutions, is such, that a violent inter- 
 change of elements takes place, and the gold is set free 
 without even electric agency; and the solutions are 
 so readily decomposed by the smallest adventitious aid, 
 that it is a practical impossibility to obtain a "reguline" 
 
8, 
 
 ELECTROTYPE MANIPULATION. 
 
 deposit, however much the voltaic power may be modi- 
 lied. 
 
 The following are illustrations of the deposition of 
 gold and silver by the mere elective affinity of ordinary 
 chemical action : If an aqueous solution of chloride of 
 gold is agitated with ether, the chloride leaves the water 
 to combine with the ether, and the resulting compound, 
 being lighter than water, floats on the surface. — If pieces 
 of polished steel are dipped into this preparation, they 
 acquire a coat of gold by ordinary chemical interchange. 
 — If a design is traced with solution of chloride of gold 
 upon a silk or linen fabric, and the fabric, while the 
 traces are still moist, be exposed to a stream of hydro- 
 gen gas (which may readily be obtained by acting upon 
 iron nails by diluted sulphuric acid), the metal is re- 
 duced, and a golden design is the result. — If a plaster- 
 cast is saturated with a solution of nitrate of silver, and 
 placed under a bell-glass, and we admit to it the gas pro- 
 duced by heating a few grains of phosphorus with alco- 
 hol and a small quantity of potash, the silver will be 
 reduced upon the surface. — If the plaster-cast is made 
 with sour whey instead of water, and is saturated with 
 silver solution, the silver is reduced by mere exposure to 
 sunlight, and forms, according to Elsren, a good conduct- 
 ing surface, in which we can deposit copper or silver 
 according to the usual modes. 
 
 The same observations apply to the ordinary salts of 
 silver, as, for example, the nitrate, &c. In fact, long 
 before the theory of chemical deposits was understood, 
 I made some experiments upon the electrolysis of this 
 
INTRODUCTORY OBSERVATIONS. 
 
 9 
 
 salt, ancl succeeded in producing an electrotype medal 
 with a silver surface, being I think the first instance of 
 electro-plating, when the object of the experiment vjas 
 electro-plating. But I was unsuccessful in my attempts 
 to repeat the experiments ; and simply because, in that in- 
 stance, I chanced to have in action a power nicely bal- 
 anced with the work to be performed, but in future 
 instances my power was not adjusted to the work. 
 
 93. The first practical process for working in these 
 noble metals is undoubtedly due to the patentees, 
 Messrs. Elkington. Others have laid claim to having 
 been the first to use solutions similar to theirs ; but 
 whatever may have been done by these others in private, 
 it does not appear that the public were in possession of 
 their processes by any authentic publication ; and there- 
 fore there is no alternative but to give the patentees 
 the claim of originality and priority. 
 
 94. The solutions they employ are the argento- 
 cyanide and the auro-cyanicle of potassium ; upon 
 which compounds it will be well if we make a few ob- 
 servations here, at the outset. They are what the 
 chemists term double salts: as, for instance, cyanide 
 of potassium is a compound simply of potassium and 
 cyanogen ; argento-cyanide of potassium is silver and 
 cyanogen combined with potassium and cyanogen, or, 
 which amounts to the same thing, cyanide of silver 
 united with cyanide of potassium. 
 
 When viewing (§ 13) what happened during the 
 decomposition of sulphate of copper, we had occasion 
 to describe that body as oxide of copper, dissolved in, 
 
 8* 
 
10 
 
 ELECTROTYPE MANIPULATION. 
 
 or combined with stdphuric acid: now, oxide of copper 
 is 1 part copper + 1 part oxygen, and sulphuric acid 
 is 1 part sulphur + 3 parts oxygen, and a certain 
 quantity of water; so that, altogether, the arrangement 
 is somewhat complex. This is not so much the case 
 with the bodies now in question. And first, in respect 
 to the simple cyanide of potassium, before it is united 
 with the gold or silver. It consists simply of one 
 equivalent of the metal potassium, and one equivalent 
 of cyanogen ) and, when it is acted upon by a voltaic 
 current in the usual way, it appears to be decomposed 
 by direct action, and cyanogen is liberated at the one 
 pole, and potassium is determined to the other, but not 
 liberated. It will be remembered (§ 13) that, in the 
 solution of sulphate of copper, water was decomposed by 
 the direct action, and that the copper was liberated by 
 a secondary action, namely, by the hydrogen of the 
 water returning back into solution in the place of the 
 copper. Well; the cyanide of potassium is decomposed 
 by direct action, and potassium is presented to the 
 negative metal ; but a secondary action now occurs : so 
 great is the affinity of potassium for oxygen, that it 
 cannot exist in a metallic form in presence of that 
 element; as is well known from the common experiment 
 of dropping a piece of potassium upon water, when it 
 combines so violently with the oxygen as to produce 
 heat and light; and the resulting products are oxide of 
 potassium, the common cattstic potash, accompanied 
 with a liberation of hydrogen. So, also, in the present 
 case ; the potassium does not itself appear, but, in its 
 
SOLUTIONS. 
 
 1 1 
 
 place, we find hydrogen and potash; it takes oxygen 
 from the water and forms potash, and sets the hydrogen 
 free. It is true, we are in possession of a means of 
 preventing its return into solution, and this is by em- 
 ploying a mass of mercury to receive it : in which case 
 it unites with the mercury and forms the amalgam of 
 potassium ; and neither hydrogen nor potash is mani- 
 fested ; but it will remain thus only under favorable 
 circumstances ; for, if the connections with the battery 
 are broken, so that the mercury ceases to be negatively 
 electrified, the potassium immediately leaves it, and 
 decomposes the water as before. Thus much in refer- 
 ence to the simple cyanide of potassium. Of the double 
 cyanides, the argento may be taken as an example. It 
 consists of 1 part cyanide of potassium and 1 part 
 cyanide of silver — the latter cyanide, like the former, 
 consisting of 1 part metal + 1 cyanogen. When a 
 solution of this double cyanide is electrolyzed, silver 
 appears at one pole, and cyanogen at the other. But, 
 in order to the production of this result, it is absolutely 
 essential that there be a considerable surplus quantity of 
 the cyanide of potassium in solution ; indeed, it is pretty 
 evident that the direct action is the decomposition of 
 the surplus cyanide, and that the silver is reduced by 
 secondary action in the following way. When the 
 metal potassium is reduced from its cyanide, it returns 
 into solution, and takes the place of the silver in the 
 double salt, setting the latter metal free ; so that, 
 while on the one hand an equivalent of simple cyanide 
 is consumed, on the other hand an equivalent is formed, 
 
12 ELECTROTYPE MANIPULATION. 
 
 and the equivalent previously engaged to form with 
 the silver the double salt, is also free; and thus far 
 there is an increase in the quantity of simple cyanide 
 of potassium. But, if the positive metal is silver, the 
 cyanogen combines with it and forms cyanide of silver; 
 for cyanogen is a gas, and like oxygen seems to combine 
 with metals in this its nascent state ; though, unlike 
 oxygen, it is a compound body, consisting of 2 equi- 
 valents of carbon + 1 of nitrogen, whence it is also 
 termed bicarb uret of nitrogen. Well ; cyanide of 
 silver is insoluble in water, and hence would form an 
 insulating crust on the silver plate were it not for the 
 presence of cyanide of potassium in excess in solution ; 
 it readily dissolves in this, and so keeps up the 
 strength of the solution ; and the extra element of 
 cyanide of potassium, mentioned above, is thus neu- 
 tralized. 
 
 Having thus described the general character of the 
 cyanide solution, it remains for us to give the processes 
 by which the several elements are most favorably 
 brought together. 
 
 95. Cyanide of Potassium. — To obtain this, we set 
 out with the ferro-cyanuret of potassium, or yellow prus- 
 siate of potash of commerce ; and as this prussiate is 
 readily accessible at all chemists', it is better in general 
 to purchase than to make it; the mode by which it is 
 obtained will be found in any treatise on chemistry. It 
 consists of 1 equivalent of cyanide of iron + 2 equiva- 
 lents of cyanide of potassium. It is of a bright yellow 
 color, and is converted into the colorless simple cyanuret 
 
SOLUTIONS. 
 
 ie 
 
 in the following manner : Take 4 oz. of the yellow 
 prussiate, break it in small pieces, and dry it well on a 
 plate of iron ; then reduce it in a mortar to exceedingly 
 fine powder. Dry and pound in like manner 1J oz. of 
 carbonate of potash. Incorporate the two ingredients 
 thoroughly. Place a Hessian crucible in the fire; and 
 when it attains a red heat, throw into it the prepared 
 mixture, and closely cover the crucible. Keep up the 
 heat, and the contents of the crucible will soon fuse, and 
 the fluid mass will become redhot. After this, immerse 
 in it, from time to time, a hot glass rod; the mass that 
 adheres to the rod in the early stages of the process is 
 brown on cooling ; as the heat is continued, it appears 
 yellowish, and finally colorless and transparent. The 
 operation is then complete; the crucible must be remov- 
 ed ; and after its contents have been allowed to settle the 
 fused mass may be poured off: the greater portion of 
 which consists of the simple cyanuret of potassium* 
 The impurities contained in this product are not detri- 
 mental to its use, in a general way, for the purposes in 
 view; however, in cases where it is required pure, it 
 must be boiled in strong alcohol ; and when the alcohol 
 cools, the pure cyanide will be deposited in the form of 
 small white crystals. This salt is very deliquescent, 
 and must therefore be retained in close bottles; it will 
 readily be recognized by its powerful odor — similar to 
 
 * This method was first described by Messrs. Rodgers, in 
 the Philosophical Magazine for Feb. 1834 ; and since by Prof. 
 Liebig. 
 
14 
 
 ELECTROTYPE MANIPULATION. 
 
 that produced by peach-blossoms. The mere mention 
 of prussic acid almost entering into its composition will 
 be sufficient to induce my readers to exercise common 
 caution in handling it. — A solvent solution is prepared 
 by adding two ounces of this salt to a pint of rain or 
 of distilled water ; when the salt is well dissolved, the 
 liquid is feidy for use. 
 
 96. Silver Solution. — Silver may be presented to the 
 above solution in various forms ; as the oxide, the chlo- 
 ride, the carbonate, the nitrate, &c. ; solution will in 
 either case occur; and the double cyanide of silver and 
 potassium will be produced. But since the silver, as 
 we hinted before, must become a cyanide of silver before 
 it can thus unite with the cyanide of potassium, it is ob- 
 vious that one portion of the solution must give up its 
 cyanogen to the silver, and take to itself the bodies pre- 
 viously in combination with that metal. So that, from 
 the oxide of silver, potash would occur in the solution ; 
 from chloride, chloride of potassa; from carbonate, car- 
 bonate of potassa ; and from nitrate, saltpetre. Of these 
 the least likely to interfere with this general action is 
 the potash ; and hence oxide of silver has been frequently 
 used. It is thus prepared : — 
 
 97. Oxide of Silver. — Place pieces of silver in a 
 glass vessel, and pour on them about equal parts of 
 water and strong nitric acid ; the metal will soon dis- 
 solve, giving off fumes of nitric oxide. Should the 
 solution have a green lw|e, which is invariably the case 
 unless the metal has bedpu obtained fine from the refin- 
 ers, it indicates the presence of copper ; in which case 
 
SOLUTIONS. 
 
 15 
 
 immerse some pieces of copper in the solution, and the 
 nitric acid, by elective affinity, will combine with the 
 copper ; and a precipitate of pure silver, in the form of a 
 grayish powder, will take place. Throw away the liquid, 
 and wash the silver precipitate several times in sulphuric 
 acid and water, and afterwards in water alone. Then 
 redissolve it, as before, in nitric acid and water ; and a 
 solution of pure nitrate of silver will be obtained. Place 
 this in an evaporating dish, or a saucer, and apply the 
 heat of a spirit-lamp, or place the saucer by the fire- 
 side, till some portion of the liquid is driven off in 
 vapor. Allow the residue to cool, and it will shoot 
 out into long, colorless, transparent crystals, which are 
 nitrate of silver. They must be handled with care, as 
 they possess the property of staining animal and vege- 
 table substances with an almost indelible black ; fused 
 nitrate of silver being the lunar caustic of surgery, 
 and the main ingredient also of marking-ink. — -Next 
 prepare some lime-water by stirring lime into water, 
 and filtering the. solution. As lime is very sparingly 
 soluble in water, requiring at 60° Fahrenheit 750 
 times its weight, it is necessary to make an abundant 
 supply. Place the lime-water in a glass or other vessel, 
 and drop in it a few crystals of nitrate of silver : the 
 colorless solution will instantly assume an unsightly 
 brown hue ; and, after remaining quiescent for a time, 
 the oxide of silver will subside in the form of a dark 
 brown precipitate. The liquid is then poured off, and 
 the precipitate is washed with water. Before throwing 
 away the liquid, fresh lime-water should be added to it ) 
 
16 
 
 ELECTROTYPE MANIPULATION. 
 
 and if the dark hue recurs, the precipitate must be 
 allowed to subside again : if no change takes place, it 
 may be inferred that the silver is all extracted. The 
 oxide of silver should not be dried, but be kept in bot- 
 tles with water. A quarter of an ounce of oxide of 
 silver, added to a pint of the solvent solution, forms a 
 very useful plating solution. 
 
 98. Cyanide of Silver. — But, as the above solution 
 is impure, in that it contains as much potash as is equiv- 
 alent to the oxide of silver added, it may not be appli- 
 cable to accurate experiments ; and as the potash is pro- 
 duced, in the formation of cyanide of silver, at the ex- 
 pense of a certain portion of the cyanide of potassium, 
 it is a wise plan, for it is no more costly, to form the 
 cyanide of silver in a separate vessel, and to wash away 
 the impurities before adding it to the solvent. Take 
 then a neutral solution of nitrate of silver; add care- 
 fully a solution of cyanide of potassium, when a white 
 precipitate of cyanide of silver will fall; continue 
 adding until precipitation ceases. The liquid, which is 
 a solution of nitrate of potash or saltpetre, is to be 
 poured off, and the precipitate well washed. It will be 
 pure cyanide of silver, if the materials employed 
 were pure ; and it is now fit to be added to the solvent 
 liquid, to form a plating solution free from impurities. 
 
 99. Preparation of the Gold Solution. — Warm a 
 pint of pure rain or distilled water, and dissolve in it 
 two ounces of cyanide of potassium as before ; then add 
 a quarter of an ounce of oxide of gold. The solution 
 will at first be yellowish, but will soon subside to color- 
 
SOLUTIONS AND APPARATUS. 
 
 17 
 
 less transparency. Those not versed in chemical ma- 
 nipulation will be wiser to purchase than to prepare 
 oxide of gold ) but, for general information, I give the 
 process : Dissolve pure gold in two measures of muri- 
 atic with one of nitric acid 5 evaporate to dryness ; dis- 
 solve the residuum in twelve times its weight of water ; 
 add to this a solution of pure carbonate of potash, dis- 
 solved in twice its weight of water ; apply a moderate 
 heat, about 170°, and a reddish-yellow precipitate oc- 
 curs. This is the hydrated peroxide of gold. Wash 
 it well ; and, to render it anhydrous, boil it in water. 
 It then assumes a brownish-black color, which is the 
 oxide required. 
 
 100. I by no means give these as standard propor- 
 tions of the several ingredients required. They are the 
 proportions which I employed with success in gilding 
 and plating the series of metals (submitted to the 
 Electrical Society at their meeting, Sept. 21, 1841), 
 by the battery process to be hereafter described. When 
 the same object is effected by the employment of a sin- 
 gle cell, it will be requisite to alter the degree of 
 saturation according to circumstances ; to which, how- 
 ever, I shall have further to allude in the sequel. 
 
 101. Single Cell for Plating and Gilding. — The 
 necessity of economizing solutions of such value as 
 these has led to certain modifications in the apparatus 
 contributing to that end. The porous cell (§ 17), 
 which in other arrangements contains the zinc and acid, 
 and is surrounded by the copper or other negative ele- 
 ment, in the present process contains the cyanide solution % 
 
 9 
 
18 
 
 ELECTROTYPE MANIPULATION. 
 
 and the negative element or object to receive the 
 deposit, and is surrounded by the zinc, &c. 
 
 102. This arrangement will be 
 Fig. 11. readily understood by a glance at the 
 
 annexed wood-cut, which represents a 
 porcelain cell containing a cylinder of 
 zinc, and an inner porous tube filled 
 with the solution of silver or gold. 
 Connection is made between the zinc 
 and medal or mould by a binding 
 screw; or by a mere contact, as in 
 the figure. 
 
 103. I must again dwell upon the 
 philosophy of the action of this ar- 
 rangement, and return to first princi- 
 ples, in order to impress them more firmly on the minds 
 of those who read these pages with the intent to repeat 
 the experiments. For it is a matter of some importance, 
 in employing the costly salts of the noble metals, to have 
 the principles of the experiment traced out as distinctly 
 as possible. 
 
 104. In the arrangement just described, the nature 
 of the deposit will depend upon the principles elsewhere 
 (§ 78) set forth; and, d fortiori, from the facility with 
 which the salts of silver or gold are decomposed, there 
 will be a much greater chance of releasing hydrogen, 
 and spoiling the experiment; to prevent which, there- 
 fore, ample provision must be made. For instance, if 
 the silver solution is weak in proportion to the energy 
 of action between the zinc and acid water, the electricity 
 
SOLUTIONS AND APPARATUS. 
 
 19 
 
 developed will be more than sufficient to release pure 
 metal, and hydrogen will be evolved, the result being a 
 deposition of oxide. Or, if the balance between the 
 strength of the solutions be duly adjusted, the relation 
 between the size of the zinc and of the medal or mould 
 may be such as to determine the same result. It is 
 therefore requisite that the water which excites the zinc 
 should contain very little acid — a few drops, more or 
 less in proportion as the cyanide solution contains more 
 or less of the oxide; and that the strength of the latter 
 should be maintained by a fresh supply of oxide from 
 time to time. 
 
 105. Another, and in some cases more convenient 
 form for the single-cell apparatus is given in the annexed 
 
 Fig. 12. 
 
 wood-cut ; in principle it differs nothing from the former ; 
 the porous cell to contain the cyanide solution being flat, 
 affords the means of immersing a larger medal, without 
 an extravagant supply of liquid. The zinc which en- 
 
20 
 
 ELECTROTYPE MANIPULATION. 
 
 velops the porous cell is also flat. The connections are 
 made as before. 
 
 106. Plating by means of a single Cell. — Having 
 charged either of these arrangements with the weak acid 
 water and the solution of silver, let it remain for a few 
 minutes, in order that the porous cell may be moistened 
 through, and that action may commence as soon as the 
 circuit is completed. Then attach a thin* pliable wire 
 to the medal or mould, and place its other end in con- 
 tact with the wire attached to the zinc : complete the 
 circuit by immersing the metal in the silver solution, 
 and a deposition will instantly take place. It will pre- 
 sent a dead whitish appearance. At the meeting of the 
 British Association in Birmingham, in 1849, Mr. Elk- 
 ington stated, "that a few drops of the sulphuret of 
 carbon, added to the cyanide of silver in the decompos- 
 ing cell, had the property of precipitating the silver 
 perfectly bright, instead of being granulated so dead as 
 it is when thrown down from the solutions ordinarily 
 employed." 
 
 107. Should the silver deposit present a whitish sur- 
 face, streaked with perpendicular black lines, it may be 
 regarded as an indication that the action is attended 
 with a development of hydrogen: this must be pre- 
 
 * This principle, so often alluded to, of retarding or restrain- 
 ing the energy of the action, is regarded in the employment of 
 thinvrire; it is a very valuable adjunct to the other means (§ 78) 
 of obtaining the same end; and may often be adopted with 
 advantage. 
 
SOLUTIONS AND APPARATUS. 
 
 21 
 
 vented by some of the means so often mentioned (§ 78, 
 &c.). By careful attention at the commencement of the 
 process the right degree of action is readily obtained; 
 and if the process is continued (with occasional watch- 
 ing) for about half an hour, the medal will be beautifully 
 coated with dead silver. In that condition it may re- 
 main, after being washed, and dried in blotting-paper. 
 Or, if a burnish is desired, the leather and plate brush 
 must be used ; or it may be thrown down bright as 
 above (§ 106). 
 
 Mr. Bain has patented an instrument which he styles 
 a " Voltaic Governor." The plates of the voltaic ar- 
 rangement are immersed to a depth sufficient to produce 
 the electricity required. They are suspended in the 
 liquid as weights to a clock-work arrangement. When 
 the. action diminishes, a keeper from an electro-magnet, 
 through which the current passes, is moved, and the 
 plates are said to sink until enough of electricity is 
 generated to cause the electro-magnet again to attract 
 the keeper.* 
 
 If, instead of plating medals, the object is to deposit 
 silver in a mould, as mentioned elsewhere, the same 
 preparations are to be made ; but the mould should be 
 allowed to remain for some minutes (more or less ac- 
 cording to the thickness required) subject to the action 
 of the current. It may then be removed, and after 
 being washed with water, and afterwards with water 
 containing a few drops of nitric acid, may be placed 
 
 * Vide Mech. Mag. 5th Aug. 1843. 
 9* 
 
22 
 
 ELECTROTYPE MANIPULATION. 
 
 with proper connections in a copper solution (§ 57), to 
 remain there till it is sufficiently backed up with this 
 metal. 
 
 108. Gilding hy means of a single Cell. — The opera- 
 tion of gilding is conducted much in the same manner 
 as that of plating — gilding, however, requiring a little 
 longer time, and occasionally hot solutions. 
 
 109. The operations of gilding and plating seem at 
 first to have been very generally effected by means of 
 the single cell, in a manner more or less in accordance 
 with the directions I have just given, as the nature of 
 the case permitted. In fact, plating by this process 
 had been adopted on a scale of some magnitude in the 
 great manufacturing town of England ; the strength 
 of the solution being maintained by fresh supplies of 
 the oxide of either gold or silver. And if attention 
 be paid to the instructions given, there is little fear of 
 failing. 
 
 110. Before describing a method which appears far 
 superior to this, I would direct attention to the source 
 whence the silver and gold in the single cell process are 
 obtained, viz., from the oxides, for instance. For every 
 ounce of these metals deposited, a quantity of the oxide 
 must be furnished which shall contain in it an ounce of 
 pure metal ; and hence for every ounce of metal, much 
 more than an ounce of oxide is consumed. The time 
 and trouble required to effect the combination between 
 these metals and oxygen are by no means inconsider- 
 able; and hence the expense of first producing the 
 oxide of gold or silver, and then releasing either from 
 
SOLUTIONS AND APPARATUS. 
 
 23 
 
 the after-combination with cyanogen, far exceeds the 
 actual cost of the metal employed : how far depends 
 upon circumstances. The object, however, may be 
 accomplished with far more certainty, and at consider- 
 ably less expense by means of an additional cell 
 (§ 56), and a plate or wire, &c. of gold or silver, to 
 keep up the strength of the solution, as in the 
 case of sulphate of copper. This method is now 
 adopted generally by the several patentees ; for experi- 
 ments with solutions of silver and gold in union with 
 cyanogen, have shown that cyanogen nascent at the 
 positive plate in a decomposition cell will combine 
 with silver and also with gold. This furnishes a 
 means of gilding and plating, by the use of a generating 
 cell to furnish the electricity, and a decomposition 
 cell to contain the cyanide solution; the nature of 
 the changes produced has already (§ 95) been de- 
 scribed. 
 
 111. Battery Process for Plating and Gilding. — 
 The generating cell for acting upon solutions of silver 
 need not be large. A pint Daniell, similar to that 
 in the wood-cut, or a series of two, is sufficient for 
 larger medals than can be placed in the decomposition 
 cell attached. The latter is of porcelain or glass. Of 
 course, the size varies according to the extent of the 
 experiment. The zinc may be used unamalgamated, 
 and excited with salt and water; the copper cell of 
 the Daniell's battery contains, as usual, a solution of 
 the sulphate (§ 57). Gilding may be better accom- 
 plished by using three cells of Daniell's battery. 
 
24 
 
 ELECTROTYPE MANIPULATION. 
 
 Fig. 13. 
 
 112. Voltaic Condenser. — Prof. De la Rive has 
 introduced an instrument, which he has named the 
 Voltaic Condenser,* and which may probably be of some 
 service in electro-gilding and plating. Its property is 
 to give to one cell of a battery the intensity of two or 
 three, being the power required for these processes; 
 and it does this at the expense of only one equivalent 
 of zinc. It is well known to electricians that at the 
 moment contact is made with the battery, so as to send 
 a voltaic current along a wire in one direction, a 
 secondary current, which endures but for an instant, is 
 induced in the wire in the reverse direction ; and when 
 contact is broken, so that the original current ceases, 
 the secondary current is induced to move in the direc- 
 
 * Vide Arch de V Elect. No. 8, p. 173, and Elec. Mag. p. 38. 
 
SOLUTIONS AND APPARATUS. 
 
 25 
 
 tion contrary to its original motion; and therefore in 
 the same direction as that pursued by the primary 
 current, when contact was first made. The intensity 
 of this current greatly depends on the quantity, the 
 character, and the form of the wire employed ; and if 
 the wire is coated with silk and wound round a bobbin, 
 the intensity is greatly increased. M. De la Rive uses 
 100 convolutions of three stout copper wires, and 
 places within the coil a bar of soft iron, the use of 
 which will soon become evident. The object of the 
 arrangement is to convey the battery current, and with 
 it the secondary current through the solution to be 
 decomposed. 
 
 113. For example, we will select the gold solution 
 to illustrate the use of the condenser. Metallic connec- 
 tions are applied between the ends of the coil and the 
 two terminations of a DanielPs or Sniee's battery. The 
 connections are continued to a vessel containing the 
 gold solution, the arrangement being somewhat like the 
 figure oo , where the generating cell is to the right, the 
 coil in the centre, and the decomposition cell to the left. 
 The current, on leaving the battery, has thus the choice 
 of two paths, the one being through the coil, the other 
 through the solution ; but from the great comparative 
 resistance of liquids, compared with metals, far the 
 larger portion would pass through the coil, while a com- 
 paratively small share would traverse the solution of 
 gold. In passing through the coil, however, it converts 
 the soft iron core into a magnet ; this magnet instantly 
 attracts a piece of iron, which is so arranged that, on 
 
26 
 
 ELECTROTYPE MANIPULATION. 
 
 being raised, it removes a wire and thus breaks off com- 
 munication between the coil and the generating cell, 
 except by means of the cell containing the solution. 
 The current therefore now passes through the gold solu- 
 tion. But when the coil ceased to be alone in the cir- 
 cuit, a secondary current was induced in the same direc- 
 tion as the original battery current ; this, therefore, 
 joins with the said generating current, and both pass 
 together through the gold solution ; by which means the 
 actual power of the battery is very greatly exalted. 
 Now, the iron core loses most of its magnetism, as soon 
 as the liquid is included in the circuit ; and hence the 
 piece of iron, the raising of which broke contact, falls 
 again, and the coil is again included, when the same 
 phenomena recur ; and thus, by a continual succession 
 of breaking and making contact, the current of a mo- 
 ment, namely, the secondary current, is created, and 
 employed with very great advantages. My readers 
 must be content with this general description ; and I 
 must trust to their own ingenuity for making arrange- 
 ments agreeable to these directions. 
 
 114. Application of Heat. — Considerable advantage 
 accrues in all cases of the deposition of metals where 
 adhesion is desired, by the use of heat. It expands the 
 baser metal, and so far opens its pores that the subse- 
 quent contraction, consequent on the effect of common 
 temperatures, is likely to operate favorably in binding 
 the metals together. It has other advantages, espe- 
 cially in gilding. The mode of heating the solutions 
 will depend entirely on the circumstances under which 
 
SOLUTIONS AND APPARATUS. 
 
 27 
 
 the experiments are conducted. If a hot stove, or a 
 sand-bath be at hand, the object is soon accomplished ; 
 but, in most cases, a simple plan is to use a lamp and a 
 glass or other retort, and convey steam by a glass tube 
 into the metallic solution, either of the single cell appa- 
 ratus, or that contained in the decomposition cell. 
 
 115. With regard to the time requisite for plating 
 and gilding, it is entirely dependent on the nature and 
 uses of the article. The thickness of the deposit, of 
 course, depends on the duration of the action. For 
 medals, and such things as are not exposed to wear, a 
 few minutes' immersion may be enough; for spoons, 
 forks, plated goods, &c, subject to much wear, six or 
 eight, or even more hours ; always taking care to watch 
 the process at times, in order to prevent the occurrence 
 of the black lines; whenever they appear, the action 
 must be retarded. Large objects, or those which are 
 subject to a long action, should be occasionally with- 
 drawn, and their position should be altered ; so that a 
 uniformity of deposit may occur. Motion of the arti- 
 cles during the process has been recommended, and with 
 some show of reason. The readiest method of produc- 
 ing it is to suspend the article in the solution from a 
 common bottle-jack, and connect the latter with the 
 battery. Or, on the large scale, when it would not be 
 convenient to have a roasting-jack for each group of 
 articles, it might be convenient to have a constant flow 
 of the solution. The surface obtained in the deposition 
 of silver by electrolysis is technically termed " dead." 
 Medals thus coated, if care be exercised during the ope- 
 
28 
 
 ELECTROTYPE MANIPULATION . 
 
 ration, are very beautiful, and should be prepared for 
 the cabinet by simply washing in water. If a bright 
 surface is desired, they are polished with a leather and 
 plate powder (§ 107). Ordinary plated goods are 
 finished off by polishing and burnishing. A steel or 
 agate burnisher is used. In articles of jewellery some^ 
 parts are left dead, and others are made bright. 
 
 116. Preparing Surfaces to unite with Gold and 
 Silver. — But we are going on too fast ; I must return to 
 certain things preliminary to plating and gilding, which 
 I had passed over, in order not to interrupt the pro- 
 gressive illustrations of the nature and preparation of 
 the solutions. I allude to the preparation of the sur- 
 faces, previous to applying the metals ) which is a point 
 of such paramount importance that, unless duly regarded, 
 all subsequent operations will be futile ; and it would be 
 vain to hope for perfect adhesion between the metallic 
 base and the deposit ; the latter will rise up in blisters 
 where the surface is not properly prepared, and can 
 easily be rubbed off. 
 
 117. There are two methods of preparing metals for 
 the reception of other metals — the wet way, and the dry 
 way. The experiments of M. Becquerel and others are 
 decidedly in favor of the latter; but, as it cannot be 
 adopted, except in certain cases, where the work of the 
 article is plain, and the article itself is not delicate, it 
 will be necessary to describe both modes. The main in- 
 tent of cleansing is that the contact between the two 
 metals may be perfect ; and it effects this by removing 
 grease and all extraneous matter, especially the oxides, 
 
CLEANSING PROCESSES. 
 
 29 
 
 which are ever found on the surface of the less noble 
 metals. 
 
 118. Cleansing ly the Dry Method. — The advantage 
 of the dry process over any in which moisture has been 
 employed, is that, in the latter case, several seconds, at 
 least, must always pass between the act of removing the 
 article from its last liquid bath, and placing it in the 
 solution of the metal to be deposited ; and during this 
 short interval, the article, or some portion of it, very 
 frequently undergoes an alteration, trivial, indeed, but 
 still an alteration, by the action of the air, which pro- 
 duces a film of oxide, infinitely thin, it is true, yet quite 
 enough to militate against the success of the experiment, 
 as regards permanent adhesion. Therefore, wherever 
 the dry process can be adopted, it is decidedly the 
 better; although, from the very nature of the articles 
 subjected to the process, the number of cases in which 
 it is available is very limited. The dry process is mere- 
 ly the operation of scouring with sand, or glass, or emery- 
 paper, as the case may be, or with very fine powder of 
 pumice-stone; using clean brushes, utterly free from 
 grease. Sometimes fine files may be used ; indeed, 
 all depends on the value and character of the article 
 operated upon. It must be remembered throughout that 
 grease and oxide are the great enemies to be expelled; 
 and therefore, especial care must be taken to avoid con- 
 tact with the moisture of the hand, which is of a nature 
 to produce either. 
 
 119. Cleansing by the Wet Method. — The solutions 
 employed may be divided generally into two classes, the 
 
 lb 
 
30 
 
 ELECTROTYPE MANIPULATION. 
 
 acid and the alkaline; the action of the former is directed 
 more towards the removal of oxides, &c. : that of the latter 
 to the removal of grease. As a rule, I would always 
 follow the use of an acid bath by an alkaline, having 
 first washed away the acid in several waters; and this 
 may be done, whether the operation commence with an 
 alkaline bath or not. The following are some of the 
 modes in use; they are all effectual according to the cir- 
 cumstances which give preference to one over the other : 
 The method recommended by M. Boettiger, in his ac- 
 count of gilding, given in the Annalen der Chimie und 
 der Pharmacie,* may be adopted. He says : " It is very 
 necessary to rub the metal according to circumstances,f 
 with extremely fine sand, moistened with hydrochloric 
 acid mixed with a little chalk, so that there shall remain 
 no trace of oxide of copper. " Another effectual method 
 is immersing the article in a mixture technically termed 
 " pickle." This may be made of 
 
 Sulphuric acid . . . .64 parts. 
 
 Water 64 <* 
 
 Nitric acid 32 " 
 
 Muriatic . . . . .1 part. 
 
 The " pickle" is used by tying a wire round the article 
 and immersing it for a second or two ; the action is very 
 energetic, and, of course, is not suited to the prepara- 
 
 * Vol. xxxv. p. 350. 
 
 f /. e. when it can be done without injury to the object of ex- 
 periment ; and this, too, must be the guide in the application of 
 the other modes. 
 
CLEANSING PROCESSES. 
 
 31 
 
 tion of medals : for medals, the mixture should be very 
 much diluted, and they should remain in it for a short 
 time. A mere bath of dilute nitric acid is often used. 
 Nitric acid, mixed with sea-salt and soot, is often rubbed 
 on the article. Concentrated sulphuric acid and sea- 
 salt is another mode. — Of the alkaline solutions are 
 caustic soda, or solution of soda and ammonia, or caustic 
 soda and sal-ammoniac ; or the articles maybe boiled in 
 a solution of common soda or potash, which is a very 
 good method of cleansing them. 
 
 120. Whatever solution is used, whether acid or al- 
 kaline, or the detergent paste of soot, or chalk and acid, 
 fresh water must not be spared for rinsing off all remain- 
 ing traces; and the article must be dried for immediate 
 use by pouring over it boiling distilled or rain water; 
 or, if the process of deposition is not to be commenced 
 immediately after the rinsing, it may be buried in hot 
 or cold boxwood sawdust, until required 5 it may often 
 be dried for immediate use in hot sawdust. In addition 
 to the detergent methods already given, an ancillary 
 means, which has been found effectual, depends upon 
 the fact that metallic and other surfaces, after exposure 
 to the air for some hours, become coated with a film of 
 air so intimately as to retain it, even (as in electrotype 
 cases) between themselves and any metal deposited upon 
 them. In fact, we have been advised, in copying large 
 subjects by electrotype, to take advantage of this, 
 and to allow the film to arrange itself, before the plate 
 is submitted to the action of the battery. For it is 
 found that the presence of this natural film very materi- 
 
32 
 
 ELECTROTYPE MANIPULATION. 
 
 ally operates in preventing adhesion between the plates 
 and the deposit : whereas, in the absence of the film, 
 unless its place has been supplied by something else, 
 other things being in order, the two will effectually be- 
 come one. We are advised, too, after soldering a wire 
 to a copper plate, to allow the latter to remain an entire 
 day, to regain the film of air which had been driven off 
 by the heat. Carrying out this principle, the boiling 
 alkaline solution and the boiling water answer a double 
 end ; and hence are very effectual means of promoting 
 perfect union between the metals. Heat operates still 
 more favorably in causing the expansion of the metal, 
 as I mentioned when recommending its adoption in the 
 process itself of electric deposition. Iron may be pre- 
 pared and cleaned by electrolytic action, as described 
 elsewhere (§ 166). In preparing steel for gilding it 
 must be polished without oil, as the oily particles ad- 
 here so closely that it is scarcely attacked by strong 
 muriatic acid. — The last cleansing method I have seen, 
 and it is a capital one, is to scour the surface with Calais 
 sand, moistened by the silver or gold solution, and rub- 
 bed in with a scratch-brush. 
 
 121. Amalgamation to promote Adhesion. — Another 
 method in this preparatory stage of the proceedings, to 
 which I shall allude, is that recommended by M. Bec- 
 querel;* and which promises to be of great avail in 
 insuring a successful termination to the experiment. 
 After the articles are thoroughly cleaned, according to 
 
 * Vide Les Comptes Eendus, July 3, 1843. 
 
CLEANSING PROCESSES. 
 
 33 
 
 the instructions now laid d own , they are dipped into a solu- 
 tion of proto-nitrate of mercury ) when taken out they 
 are washed in abundance of water ; and are then rubbed 
 with leather, in order to promote the equal spread of 
 the mercury. These operations are repeated until the 
 whole surface is well coated with mercury. The ultimate 
 character of the metallic deposit depends on the surface 
 given to the mercury ; if the employment of the leather 
 is only such as is needed to effect the more equal diffu- 
 sion of the mercury, the surface is dull or dead, and so 
 is the deposit ; whereas, if brisk friction is applied, and 
 the mercury receives a good polish, such will be the 
 character of the metal thrown down. And thus may 
 burnished gold or dead gold be produced at pleasure. 
 By adopting this method of giving a mercurial coat as 
 the foundation for the plating or gilding (and it is espe- 
 cially valuable for the latter), a double advantage ac- 
 crues ; the close adherence between the metals is insured 
 — and a coating of gold of any thickness may be thrown 
 down. The mercury is subsequently driven off by heat; 
 either heat applied for the purpose, or the heat employed 
 in some of the operations by which the work is finished. 
 
 122. German silver is prepared by allowing it to 
 remain for three or four hours in a cold solution of car- 
 bonate of potash. It is then washed in cold water, and 
 dipped into dilute nitric acid. After again washing 
 and drying it, it is rubbed with leather ; and imme- 
 diately before placing it in the silver solution, it is 
 dipped into a solution of common salt, containing a 
 little gum. 
 
 10* 
 
34 
 
 ELECTROTYPE MANIPULATION. 
 
 123. Cleaning Electro-plate. — Electro-plating, espe- 
 cially of dead silver, is very liable to turn yellow, after 
 a few days' exposure to the light. M. Mourey found* 
 that this was due to the decomposition of a cyanuret or 
 a sub-cyanuret remaining on the silver surface on its 
 emersion from the solution. He removes it in the fol- 
 lowing manner : The articles are covered with a thick 
 layer of dissolved borax, and, being placed in a muffle, 
 are submitted to a heat somewhat below cherry-red, 
 which is sufficient to calcine the borax. They are then 
 thrown into water acidulated with sulphuric acid, and 
 allowed to remain. After being withdrawn from this, 
 they are washed in water and dried, first in hot sawdust 
 and then on a stove or otherwise. The result is the 
 production of that white color so essentially requisite 
 to dead silver, especially in articles of jewellery. I 
 may add to this a process for cleaning tarnished silver 
 in general, which, though not much known here, is 
 practised constantly by the natives in India. A few 
 tamarinds are placed in water contained in an earthen 
 vessel, and the silver articles are boiled in it for a time, 
 and they emerge clean and very white. 
 
 124. Gilding-Wax. — The proper color is given to 
 the surface of electro-gilding by covering it with 
 gilding-wax, and heating it till the mass begins to 
 smoke. Gilding-wax consists of the powders of salt- 
 petre, sal-ammoniac, sulphate of iron, and verdigris, 
 mixed with melted wax. This operation removes the 
 
 * Vide Comptes Renclus, April 3, 1843, p. 660. 
 
SOLUTIONS. 
 
 35 
 
 brassy appearance, which the surface often presents, and 
 gives the rich gold color, on which the beauty of the 
 work depends. 
 
 125. Various Metallic Solutions. — M. Louyet has 
 used with great success a solution of bisulphuret 
 of gold in cyanuret of potassium. This solution is 
 neutral to silver, copper, and brass, so that no action 
 occurs on the surface of these metals until the circuit 
 is completed. The bisulphuret of gold is prepared by 
 passing sulphuretted hydrogen through a solution of 
 bichloride of gold; or by pouring into such solution 
 hydro-sulphate of ammonia. The bisulphuret is col- 
 lected in a filter, where it must be well washed with 
 warm not boiling water : it is then dissolved by pouring 
 the cyanuret solution (§ 95) through the filter. The 
 solution has a clear gold color; it is diluted for use to a 
 pale straw color. 
 
 126. M. Becquerel has introduced a very philoso- 
 phical mode of gilding by the single cell process. A 
 solution was made of 1 gramme of dry chloride of 
 gold, 10 of ferro-cyanuret of potassium,* and 100 
 of water; it was filtered, and to it were added 100 
 grammes of a saturated solution of yellow ferro- 
 cyanuret of potassium : The solution was used in that 
 state, or diluted with once or twice its bulk of water, 
 according to the character of surface desired. This 
 solution is placed in the porous tube of a single cell 
 (§ 18), and into the cell surrounding the zinc is poured 
 
 * The prussiate of potasli of commerce. 
 
36 
 
 ELECTROTYPE MANIPULATION. 
 
 a solution of a similar character, with the exception that 
 it does not contain any gold; but, in lieu thereof, it 
 contains a little common salt. Unamalgamated zinc is 
 used. 
 
 127. There is not space to give detailed accounts of 
 the many other solutions that have been used; let it 
 suffice to mention in brief a few : — 
 
 M. de Ruolz has employed, 
 
 1. Cyanuret of gold, dissolved in simple cyanuret of 
 potassium ; 
 
 2. Cyanuret of gold, dissolved in the yellow ferro- 
 cyanuret ; 
 
 3. Cyanuret of gold, dissolved in the red ferro- 
 cyanuret of potassium; 
 
 4. Chloride of gold dissolved in the same cyanurets ; 
 
 5. Double chloride of gold and potassium dissolved 
 in the cyanuret of potassium ; 
 
 6. Double chloride of gold and sodium dissolved in 
 soda;* 
 
 7. Sulphur et of gold dissolved in neutral sulpliuret of 
 potassium. 
 
 The latter is said to be singularly valuable. 
 
 He uses cyanuret of silver in yellow ferrocyanuret 
 of potash. Where 6 cells in series are required for 
 gilding, 4 are sufficient for plating. 
 
 128. He effects platinating with the double chloride 
 of platinum and potassium in caustic potash, with the 
 same ease and facility as plating and gilding ; but when 
 
 * Tlie analogous salt of potash does not succeed. 
 
SOLUTIONS. 
 
 37 
 
 he used cyanuret solutions of platinum, like those of 
 gold or silver, it required one or two hundred times the 
 duration of the experiment to produce a corresponding 
 result. 
 
 Lead is precipitated from oxide of lead dissolved in 
 potash. 
 
 Tin is deposited on iron and zinc, &c, from a solu- 
 tion of oxide of tin in potash, or tin in cream of tartar; 
 which latter is the solution employed for tinning pins, 
 the process being in truth an electrical one ; for the 
 pins and the tin are thrown into the liquid, where tlie 
 latter receive a coating. 
 
 Zinc is deposited, especially on iron ; the solution is 
 not named.* Elkington's solution for zincing is given 
 in the sequel (§ 138). 
 
 129. M. Boettiger uses for gilding one part of chlo- 
 ride of gold, as neutral as possible, and 100 parts water, 
 in which he allows the action to be repeated about half- 
 a-dozen times, of a minute's duration each, and washes 
 the article between each operation with fine linen in pure 
 water. For platinating, he has a corresponding solution 
 of platinum. He has also employed one part of chloride 
 of platinum, 100 parts water, and 8 parts hydrochlorate 
 of soda; or one part ammoniacal chloride of platinum, 
 dissolved with 8 parts of sal-ammoniac, in 32 or 40 parts 
 of water. The latter solutions are used without the 
 voltaic current to give a thin coating ; which may doubt- 
 less be increased by the voltaic action. 
 
 130. Mr. Woolrich uses the following solutions : — 
 
 * Vide Les. Archives, June 7, 1842. 
 
38 
 
 ELECTROTYPE MANIPULATION. 
 
 He first prepares what he terms the solvent, or sul- 
 phite of potash, thus: 28 lbs. of the best pearlash, 
 and 30 lbs. of water are boiled in an iron vessel ; the 
 solution is allowed to cool, and is then filtered. To this 
 are added 14 lbs. of distilled water \ sulphurous acid gas* 
 is then passed into the liquor until it becomes saturated; 
 and the liquor is filtered for use. 
 
 Silvering -liquor. — 12 oz. of crystallized nitrate of 
 silver are dissolved in 3 lbs. of distilled water. The 
 solvent just described is gradually added, so long as a 
 whitish precipitate falls. The supernatant liquor is 
 poured off, and the precipitate washed with distilled 
 water. To the washed precipitate is added as much of 
 the solvent as will dissolve it ; and then ith part more, 
 so that the solvent may be in excess. After being well 
 stirred, and allowed to remain for 24 hours, the liquor 
 is ready for use. 
 
 Gilding -liquor. — Four oz. troy of fine gold are 
 dissolved in a mixture of 11 fluid oz. nitric acid, 13 
 muriatic acid, and 12 distilled water; the solution is 
 evaporated and crystallized; and the crystals are dis- 
 solved in 1 lb. of distilled water : the gold is then pre- 
 cipitated by pure magnesia, the precipitate is first washed 
 with distilled water acidulated with nitric acid, and then 
 with water alone. To the washed precipitate is added 
 
 * This gas may be obtained by applying heat to a flask con- 
 taining sulphuric acid and pieces of well-burned charcoal. The 
 gas should be passed through water to free it from any acid it 
 may have carried over. 
 
SOLUTIONS. 
 
 39 
 
 enough solvent to dissolve it, and jth more. After being 
 stirred and remaining 24 hours, it is fit for use. 
 
 Coppering -liquor. — 7 lbs. of sulphate of copper are 
 dissolved in 30 lbs. of distilled water, and to this is 
 added solution of carbonate of potassa until precipitation 
 ceases. The precipitate is washed, and dissolved in the 
 solvent as before, one-third more being added. This 
 must stand for twenty-four hours, like the others. 
 
 131. Mr. Tuck has prepared the following liquid. 
 He dissolves 70 parts by weight of bicarbonate of am- 
 monia in distilled water, to which he adds by weight 56 
 parts of sulphate of silver, or 134 parts of cyanide of 
 silver, and boils the liquor until the silver salt is entirely 
 dissolved. The strongest solution that he has employed 
 was in the proportion of half an ounce of sulphate of 
 silver and 107 grs. of bicarbonate of ammonia to a pint 
 of distilled water. 
 
 132. Mr. Briant, of St. Petersburg, gives the fol- 
 lowing preparation of gold solution, as superior to any 
 other. He makes a solution of 6 J solotnik (428 grs.) 
 of gold in aqua regia (nitro-muriatic acid), by aid of a 
 sand-bath ; he boils it down to one-fourth, when crystal- 
 lization occurs; he evaporates, but not to dryness. The 
 crystals are then dissolved in hot water, and half a 
 pound* of powdered magnesia dissolved in water is 
 added. It is filtered warm ; if the liquor is dark, the 
 magnesia is not all dissolved, when it must be boiled 
 
 * A Russian pound, of 96 solotniks, is equal to 6318.5 grs. 
 Eng. 
 
40 
 
 ELECTROTYPE MANIPULATION. 
 
 again. It is now washed in the filter, and the hydrated 
 oxide of gold remaining in the filter is placed in a flask, 
 and on it is gradually poured half a Russian pound of 
 nitric acid; after the effervescence ceases, it is again 
 filtered and well washed; and the chocolate-colored resi- 
 duum is boiled in a hot prepared solution of 1 lb. 22 
 solotnik (7766 grs.) of prussiate of potash; when it 
 boils, 10 solotnik (6.58 grs.) of caustic potash, previously 
 dissolved in cold water, are added, and well mixed. When 
 cool, the solution is filtered for use ; the sediment now 
 remaining in the filter is oxide of iron. 
 
 133. Major Von Jewreinoff gives the following silver 
 solution : 4 parts of dry powdered prussiate of potash 
 are well incorporated in a mortar with 1J parts of pure 
 potash, and are melted in a closed vessel till the product 
 becomes transparent and dazzling white. Chloride of 
 silver, prepared by throwing salt into a solution of 
 nitrate of silver, is dissolved in this solution and fil- 
 tered for use. 
 
 134. A writer in the 3fec7ianics' Magazine, Mr. 
 Eockline, has used the following solution : Oxide of 
 silver is dissolved in citric acid; the solution is evapo- 
 rated to dryness, and the residual salt is exposed in a 
 tube to 212° Fahr., when a current of dry hydrogen is 
 passed over it for a few minutes. The salt is then dis- 
 solved for use in cold water. He says this solution 
 must not be heated. 
 
 135. Other applications of Electro-gilding. — On 
 the continent, and here also, this art has been rendered 
 available in gilding the springs and works of chrono- 
 
SOLUTIONS. 
 
 41 
 
 meters'; and one experimentalist, M. Perrot, has " un- 
 dertaken to gild at the same time all the movements of 
 a watch — to gild them, not only in their places, but 
 while in motion.* M. Boettiger, to whom I have al- 
 ready (§ 129) alluded, has employed for gilding the 
 bichloride of gold, and has prepared copper surfaces, 
 by first depositing platinum upon them. M. Hamman, 
 an engraver of Geneva, has deposited a coat of gold 
 instead of one of varnish on plates intended for ordinary 
 etching, and has traced the design most accurately, 
 through this exceedingly delicate layer. 
 
 136. Electro-gilding has been successfully applied in 
 protecting and permanently fixing Daguerreotype pic- 
 tures. It is well known that thin films of gold are 
 transparent. A thin film is therefore deposited upon 
 the surface of the finished plate, and effectually secures 
 the picture from destruction ; while it does not in the 
 least hide it from the eye, or detract from its beauty. 
 The silver surface of Daguerreotype plates is greatly 
 improved by depositing upon them a thin film of silver, 
 and subsequently polishing them according to the usual 
 plan. 
 
 137. Daguerreotype Plates. - — The art of electro- 
 plating may be made available in preparing Daguerre- 
 otype plates. The lovers of this attractive art (which 
 is so well explained in the third and fourth numbers of 
 this series of Manuals), may thus experiment upon 
 plates of their own preparation. They may be prepared 
 
 * Vide Arch, de l'Electricite, No. I. p. 276. 
 
 11 
 
42 
 
 ELECTROTYPE MANIPULATION. 
 
 in two ways : either by plating a burnished and pre- 
 pared copper plate ; or by depositing silver, with due 
 precautions, on a burnished plate, and afterwards back- 
 ing up with copper. The latter is the most effectual, 
 especially to those who are not skilled in the plans 
 adopted by the artisan for the treatment of burnished 
 surfaces. 
 
 138. Electro-zincing. — Messrs. Elkington have pa- 
 tented a process for applying zinc to iron, in order to 
 protect it from the atmosphere. They say that the best 
 and cheapest solution is the sulphate of zinc, of which 
 they dissolve a pound in a gallon of water ; and elec- 
 trolyze it with a battery of feeble power. This is not 
 the well-known galvanized iron. The latter is prepared 
 by immersing the iron in melted zinc ; which process 
 gives to it a coat of the latter metal, that acts as a most 
 valuable protection against the corrosive influences 
 of the atmosphere, as will be seen in the fifth of these 
 Manuals, which treats upon the " Electric Telegraph/' 
 for which it is extensively used. 
 
 139. Reduction of Alloys. — This has been long 
 deemed impracticable ; but recent experiments have 
 proved that it is possible. M. de Ruolz was the first to 
 deposit a galvanic film of bronze on other metals, by 
 dissolving cyanide of copper and oxide of tin, in certain 
 proportions, in cyanide of potassium, and allowing a 
 constant battery to act upon the solution. Professor 
 Majocchi reports the deposition of an alloy of lead and 
 iron, which he says is much harder than lead, and 
 melts at a much higher heat. Protosulphate of iron is 
 
SOLUTIONS AND APPARATUS. 
 
 43 
 
 added to a solution of lead and nitric acid, in such 
 quantity that the resulting solution shall not be very 
 concentrated. Professor Jacobi obtained films of brass 
 by preparing solution of cyanide of potassium, and 
 throwing in copper, from a positive plate of copper, and 
 then zinc from a positive plate of zinc ; after a certain 
 time brass was given off. I have repeated Jacobi' s ex- 
 periments, and made many hundred original ones, with 
 very various solutions, to discover whether it were pos- 
 sible to obtain a solution that should continue to give 
 off brass. I have obtained deposits of most brilliant 
 brasses, but all the solutions yet operated upon have 
 failed to retain their properties beyond a day or two : 
 new chemical combinations occur. 
 
 The following are Mr. Joseph Steele's processes : — 
 Electro-tinning. — Warm 75 gallons of distilled 
 water ; in parts of it dissolve separately 60 lbs. of com- 
 mon soda, and strain ; 15 lbs. of Russian or American 
 potash, and strain \ 5 lbs. caustic potash j 2 oz. cyanide 
 of potassium ; 2 oz. acetate of zinc ; 16 lbs. bioxide of 
 tin : mix the first three solutions, and then add the 
 last three, and let the whole stand for two or three 
 hours. Use a piece of tin as the positive plate in the 
 decomposition cell. 
 
 Electro-brass. — Warm 6 gallons of distilled water ; 
 dissolve separately 2? lbs. American potash; 2 J oz. 
 powdered acetate of copper, previously mixed with half 
 a pint of strong spirits of ammonia ; 4 or 5 oz. sulphate 
 of zinc ; 2 oz. cyanide of potassium. For copper de- 
 
44 
 
 ELECTROTYPE MANIPULATION. 
 
 posit, leave out sulphate of zinc. It is better to let 
 the mixture stand for three or four days before using. 
 
 140. Electrolysis of fused Compounds. — Mr. Arthur 
 Wall has a patent for purifying iron ore from sulphur, 
 phosphorus, and other such elements, by applying a 
 powerful voltaic current to the metal while in a state of 
 fusion, either when it is in the smelting furnace, or 
 while it is in the moulds; and he prefers continuing the 
 current until the metal is solidified. In reference to 
 these experiments, Dr. Ure is understood to have stated 
 that a current was passed through a rod of soft iron, at 
 a moderate heat, and in a few hours it was converted 
 into steel. 
 
 141. Mr. Napier has patented a process for reducing 
 copper from its ore by the aid of an electric current. 
 Native sulphuret of copper, for instance, is roasted in 
 the usual way, and is then melted with lime and soda as 
 fluxes ; the pot is now so connected with a battery as to 
 be the negative pole, or place for receiving deposits ; and 
 a plate of iron connected with the positive pole is thrust 
 beneath the surface of the fluid mass ; a solid mass of 
 copper is soon found deposited on the inner surface of 
 the pot, the quantity of which is stated to be more than 
 a dozen times that of the chemical equivalent of the 
 electric action. 
 
 142. Mr. Parker has a patent for plating and gilding 
 by means of fused iodides, chlorides, and phosphates 
 of the metals. As an example, he takes 6 lbs. of 
 chloride of silver, fused in a silver or an enamelled 
 iron vessel ; when fluid, he immerses in it the article to 
 
SOLUTIONS AND APPARATUS. 
 
 45 
 
 be plated, which is in connection with the negative end 
 of the battery, and a plate of silver connected with the 
 positive end 5 to increase the quantity of fluid, he some- 
 times adds to it from 3 to 10 lbs. of iodide of potassium, 
 or even the iodide of mercury or copper, in the propor- 
 tion of 1 or 2 lbs. 
 
 For a gold fluid he takes 20 oz. of iodide of gold 
 and 80 oz. of iodide of potassium or sodium, which he 
 subjects to similar treatment, using, of course, a gold 
 instead of a silver plate. 
 
 143. Mr. Ritchie has a patent for extracting copper 
 from its ore by a very simple voltaic arrangement. He 
 dissolves the calcined copper ore in dilute sulphuric acid, 
 and places the solution in a large rectangular vessel ) 
 on the upper surface of this, he pours a mixture of two 
 parts water and one saturated solution of sulphate of 
 iron, taking care that mixture does not take place with 
 the lower liquid ; he then places an iron plate as a ge- 
 nerating metal in the iron solution, and a plate of lead 
 in the copper solution to receive the deposit, connecting 
 the lead and iron with a wire. — It is also stated that, 
 by this process, galvano-plastic objects may be easily 
 obtained on a large scale. 
 
 144. Magneto-electro Machine. — We are here called 
 upon to notice another means of obtaining electric 
 currents, inasmuch as it has been successfully applied 
 by Mr. Woolrich of Birmingham, to gilding and plating. 
 A magnet has the property of generating electric cur- 
 rents in all metals that are in motion, within the sphere 
 of its influence ; but only while they are in motion. 
 
 11* 
 
46 
 
 ELECTROTYPE MANIPULATION. 
 
 By proper adjustment, these effects may be exalted. 
 In practice, powerful horseshoe magnets are employed, 
 and great lengths of silk-covered copper wire, wound 
 upon bobbins with iron cores, are made to revolve in 
 front of the magnetic poles, by the action of a small 
 steam-engine. Arrangements are made to intercept 
 the currents at the ends of the coils, and to convey 
 them into a trough containing the metallic solution. 
 By sliding a keeper along the magnet to various dis- 
 tances, the force of the current is modified. A single 
 machine will reduce five ounces of gold per hour. A 
 large machine was constructed that was calculated to 
 have deposited twenty ounces per hour; but it is 
 thought to have been damaged by other experiments. 
 The steam power for driving twenty such machines is 
 stated to cost only 15s. per week — the wear and tear is 
 small. But, all things considered, the Messrs. Elking- 
 ton have found it more profitable to continue the 
 employment of the Voltaic Battery in their extensive 
 works. 
 
 Dr. Braun is employing, it is said, one of these 
 machines at Rome, for producing electrotype copies 
 from casts of the works of art in that city, as referred 
 to hereafter (§ 181). 
 
DEPOSITION OF OXIDES OF METALS ON METALS. 47 
 
 II.— DEPOSITION OF THE OXIDES OF 
 METALS ON METALS. 
 
 145. Metallo-cJiromes. — Hitherto we have been con- 
 sidering the deposition of metal on metal ; it remains to 
 give a familiar description of the mode of depositing 
 metal in union with oxygen, i. e. a metallic oxide on 
 metals. The most beautiful experiments of this kind 
 are those described by Nobili,* and recently repeated 
 and considerably modified by Mr. GJ-assiot.f The pro- 
 ductions are known by the name of metallo-chromes. 
 A saturated solution of acetate of lead is prepared, and 
 poured into a shallow vessel, in which has been placed 
 a highly-polished steel plate. A wire from the positive 
 end of a series of three or four Daniells, is made to 
 touch the plate. Then, if another wire from the nega- 
 tive end of the series is held in the solution, over the 
 plate, a small tinted circle makes its appearance on the 
 polished surface beneath the wire, and rings of color 
 of the most brilliant hues rise from the centre and 
 expand to the circumference. The colors commence 
 with silver-blond, and progress onwards to fawn-color, 
 and thence through various shades of violet to the in- 
 digos and blues ; then through pale blue to yellow and 
 orange ; thence through lake and bluish lake, to green 
 and greenish orange, and rose orange ; thence through 
 
 * Scient. Memoirs, vol. i. art. 5. 
 
 f Proceed. Elec. Soc. Dec. 17, 1839, 4to. 
 
48 
 
 ELECTROTYPE MANIPULATION. 
 
 greenish violet and green, to reddish yellow and rose lake, 
 which is the highest color on the chromatic scale. 
 
 146. Colored figures of varied character are obtained 
 by modifying the shape of the electrode connected with 
 the negative end of the battery; using instead of a point 
 a slip of metal, a disk, a ring, a convex or a concave cir- 
 cle, a cross, or other pattern. By the employment of a 
 large disk, and small steel plates, and by very careful 
 manipulation, a uniform tint may be given to each plate, 
 and the chromatic scale of forty-four colors may be 
 obtained. For this purpose each experiment must be 
 timed by a pendulum, and one second being given to 
 the first plate, the duration for the rest must increase 
 by a second for each. It is absolutely essential in ope- 
 rations of such extreme delicacy that all the plates be of 
 the same thickness, so that, when adjusted to their posi- 
 tion, they may remain at the same distance from the 
 disk. Many more than forty-four specimens will be 
 produced, which must be placed in order, and the simi- 
 lar tints rejected. The spoiled plates are cleaned with 
 fine emery paper. — The best metallo-chromes are ob- 
 tained by cutting a star or other pattern in card, and 
 placing the pattern on the plate, beneath a convex or a 
 concave disk. 
 
 The colors arise from the very thin films of oxide of 
 lead that are deposited on the steel plates, and are due 
 to an analysis of light, similar to what occurs in a soap- 
 bubble,* or in the film of air between a lens and a plate 
 
 * The best mode of making a soap-bubble is to place a piece 
 of soap, about as large as a pea, in a six-ounce vial, one-third 
 
DEPOSITION OF OXIDES OF METALS ON METALS. 49 
 
 of glass, closely pressed together. No practical use had 
 been made of these films. 
 
 147. Deposition of Oxide of Lead. — M. Becquerel 
 has described* a means of coating metals with oxide of 
 lead and oxide of iron, for the purpose of protecting 
 them from the action of the air. He uses a potash solu- 
 tion of lead, which is prepared by dissolving 200 gram- 
 mesf of caustic potash in two litres J of distilled water, 
 and adds to it 150 grammes of protoxide of lead — the 
 litharge of commerce. — It is boiled for half an hour, and 
 after being allowed to settle, is diluted for use with its 
 volume of water. Some of the solution is poured into 
 a porous tube, which is placed in a vessel containing water 
 acidulated with one-twentieth its weight of nitric acid. 
 The nitric acid contains a platinum plate, connected 
 with the negative or zinc end of a single cell of Daniell's 
 battery ; and the article to be coated with oxide of lead, 
 as, for instance, a plate of iron, is placed in the solution 
 of lead, and connected with the copper of the battery. 
 In a few minutes the plate is covered with a coating of 
 peroxide of lead, which arises from the union of the 
 oxygen with the protoxide of the solution. The adhe- 
 rence is very strong, and if the article has been well pre- 
 
 filled with water ; the vital is to be then placed in a vessel of 
 water, and the water to be boiled. When the vial gives off steam 
 pretty freely, it is to be corked, and then removed and sealed 
 immediately. A horizontal film of soap may at any time be 
 made by shaking the vial. 
 
 * Vide Comptes Rendus, July 3, 1843. 
 
 f A gramme=15J gr. troy. J A litre=61 cub. in. 
 
50 
 
 ELECTROTYPE MANIPULATION. 
 
 pared (§ 116, &c), will sustain the action of the burn- 
 isher. The color of the deposit is black with a brown- 
 ish tinge; if the action is allowed to continue, it assumes 
 the tint of yellow ochre. The liberation of hydrogen 
 on the platinum plate is a sign that things are going 
 on well. The solution must not be used to exhaustion, 
 but be replaced by fresh, after perhaps a dozen hours of 
 action. 
 
 148. Deposition of Oxide of Iron. — An ammoniacal 
 solution of iron is used for obtaining a deposit of the 
 peroxide. A hot solution of protosulphate of iron is 
 prepared, and placed in the receiver of an air-pump, 
 to abstract from it all air : a solution of ammonia is 
 likewise deprived of air, and a little more than is suf- 
 ficient to dissolve the protoxide of iron is poured into 
 the former solution. This solution is used in the same 
 manner as that of lead, described in the preceding 
 paragraph, namely, in a diaphragm decomposition cell; 
 but care must be taken to keep it covered from the air, 
 which has so great a power, on account of the oxygen 
 it contains, of converting the protoxide into a peroxide. 
 A few minutes suffice for the operation. The deposit 
 of peroxide is of a brownish-red color, having somewhat 
 the appearance of precipitated copper; if the action 
 continues, the color becomes darker, and finally it is 
 deep violet. The oxide will endure the burnisher. 
 If the action is carried on at an elevated temperature, 
 the adhesion is greater, because the contraction of the 
 expanded metal binds the film more closely. The use 
 of the diaphragm in these operations is to prevent the 
 
ELECTRO-ETCHING. 
 
 51 
 
 solution from becoming exhausted; for if the experiment 
 were carried on under ordinary circumstances, the de- 
 position of metal at the one electrode, and oxide of 
 metal at the other, would very soon deprive the solution 
 of its contents. 
 
 IH. ELECTRO-ETCHING. 
 
 149. The results hitherto treated on, have been (with 
 the exception of the deposition of the oxides), all ob- 
 tained at the negative metal; but there is a class of 
 results of no inconsiderable importance to be obtained 
 at the other terminal. 
 
 The plates of copper, in the decomposition cell, in 
 connection with the copper of the battery, have been 
 described as combining gradually with the oxygen 
 released there, and being eventually consumed ; so 
 likewise the plates of silver or gold, which occupy the 
 same relative position, are in a similar manner con- 
 sumed. But as the varnish (§ 31), placed on moulds, 
 effectually shields the parts protected by it, from the 
 effects of electrolytic action, so also may the copper 
 plates, or the plates of any metal connected with the 
 positive end of the battery, be protected, and the 
 destructive action localized at pleasure. 
 
 150. If, for instance, plates of copper be covered 
 on any part of their surface with a stratum of varnish, 
 that part will be excluded from the line of action, while 
 all else is being consumed. Advantage has been taken 
 
52 
 
 ELECTROTYPE MANIPULATION. 
 
 of this, by coating plates with proper composition and 
 then tracing through it any design, of which an etching 
 is required. The plate in this condition is submitted 
 to the action of the nascent oxygen, and the surface is 
 readily and effectually etched. There is some superio- 
 rity too possessed by this method, over the ordinary 
 etching by the use of nitric acid ) for the operation 
 can be conducted with considerable regularity ; it can 
 be rendered a slow or a speedy process ; and the result 
 can be taken out, from time to time, to be examined, 
 and can be re-submitted in a moment. In fact, of 
 so much importance has this mode of etching been 
 deemed, that it is already one amongst the many 
 applications of this principle for which a patent has 
 been obtained. 
 
 151. Process of Electro-etching. — Take a burnished 
 copper plate, and solder to it a stout wire : heat the 
 plate, and rub its surface with etching-ground,* 
 wrapped in silk ; be careful to obtain an even coating ; 
 then smoke the covered surface over the flame of a 
 candle. Varnish the back of the plate, as well as the 
 wire, with shell-lac. Trace the design through the 
 etching-ground with a fine point. This done, place it 
 in a decomposition cell, and connect it with the copper 
 of a DanielFs or other cell, placing opposite to it a 
 plate of somewhat similar size ) after the lapse of ten 
 minutes remove it, and " stop out" the fine parts with 
 
 * Etching-ground consists of asphalte, wax, black pitch, 
 and Burgundy pitch. 
 
ELECTRO-ETCHING. 
 
 53 
 
 Brunswick black; return it to the decomposition cell 
 for a second ten minutes ; and again stop out the half 
 tints; again submit it to action for ten minutes, and 
 the operation is complete. Remove the etching-ground 
 by means of heat, and a perfect engraving will be found 
 on the plate. The exact duration of the several opera- 
 tions, as well as their number, must be regulated accord- 
 ing to circumstances. Electro-etching is an interesting 
 experiment for the lecture-table. At the commencement 
 of a lecture, I have submitted a plate to electric action, 
 and, before the hour has expired, have distributed proof 
 impressions. 
 
 152. An etching-ground of gold may be applied by 
 submitting a copper plate, well varnished on the back, 
 to the action of an electric current passing through a 
 solution of the cyanide of gold. When a perfect coating is 
 obtained, the plate is removed ; and the design is etched 
 with a fine point through the gold film. The plate is 
 then submitted to the action of the battery, as before ; 
 and as the oxygen, released there, combines with the 
 copper, but not with the gold, the design is permanently 
 etched. — The process of etching is very speedily effected; 
 and must, therefore, be very carefully attended to, lest, 
 by proceeding too far, the plate be spoiled. 
 
 153. Electro-etching Daguerreotype Plates. — In the 
 description last given, the artist's hand must first trace 
 the design, before the electric force will engrave for 
 him ; but Mr. Grove has described a process* by which 
 
 * Vide Proceed. Elec. Soc. vol. i. p. 94. Aug. 17, 1841. 
 
54 
 
 ELECTROTYPE MANIPULATION. 
 
 the pencil of nature does all the work. He lias taken 
 Daguerreotype plates — those beautiful productions 
 " drawn by light/' and having submitted them to the 
 still further operation of Nature's laws, has succeeded in 
 " engraving by electricity." 
 
 154. Though this process has not been perfected, so 
 far as to produce plates fitted in all respects for the 
 printer, yet, as it is a very important and instructive 
 application of the subject on which we treat; and as 
 it furnishes, though not for the printer yet for the elec- 
 trotypisty plates from which he can obtain perfect im- 
 pressions, and these to any extent, it claims especial 
 notice in this treatise. 
 
 155. Nature of Daguerreotype Pictures. — The dark 
 portions of these pictures are considered to be silver, 
 and the light portions mercury ; and hence, if they are 
 placed in a solution, whose liberated element shall act 
 on one of these metals, and not on the other; or if they 
 are submitted to a solution, the liberated element of 
 which combines more with one than the other, the result 
 will be an etching. 
 
 156. Hydrochloric acid, diluted with half its bulk of 
 water, has been employed. From hydrochloric acid, 
 hydrogen is released at the negative plate; and the great 
 object is to dispose of it regularly, and as speedily as may 
 be; for, if any hydrogen adheres to the surface of this 
 plate, the surface of the plate to be etched, where it is 
 opposed to this, will furnish an irregular result. The 
 best plates for parting with the nascent hydrogen, are 
 platinized silver, or platinized platinum. The distance 
 
ELECTRO-ETCHING. 
 
 55 
 
 between the two plates (which are, of course, placed 
 parallel) should be about the fifth of an inch, which is 
 near enough to insure uniformity of action, and not so 
 near as to allow the escaping hydrogen to interfere with 
 the result. 
 
 157. In a process so delicate as that of etching out 
 the microscopic delineations on these plates, due regard 
 must be paid to the relation between the size of the 
 generating pairs and the size of the plates themselves. 
 The best mode is to have the generating pair and the 
 decomposing pair of one size, or nearly so; and, as the 
 solution employed will give up its elements with a feeble 
 current, one generating cell is enough. Prof. Grove 
 used a single pair of the nitric acid batter?/; but any 
 other will produce the desired result. The time of action 
 depends on the nature of the generating cell employed. 
 With the nitric acid battery (which is very energetic in 
 its action), the effect was produced in from 25 to 30 
 seconds. With other arrangements it will be longer \ 
 and, possibly, as it is accomplished more slowly, the 
 result will be more definite ; and the experiment will be 
 less liable to fail. 
 
 158. Having determined these several points, and 
 shown the reasons on which they are based — (and I always 
 wish to furnish reasons for all that is done ; for when a 
 man acts by mere directions, and arrives at ends he 
 knows not why, I am well assured that his interest in 
 the subject will soon be dissipated, and his path, instead 
 of being pleasing and bright, will be dull and gloomy) — 
 the next arrangement is to prepare a wooden frame with 
 
56 
 
 ELECTROTYPE MANIPULATION. 
 
 grooves into which the two plates, viz., the Daguerreo- 
 type* and the platinized plate can slide, so as to remain 
 firmly fixed in the required position. This frame is 
 then immersed in the solution, and contact is made with 
 the generating cell by touching, with the ends of the 
 connecting wires, the edgesf of the plates ; and retain- 
 ing them in contact for the given time. " The plate 
 is then removed, and well rinsed in distilled water, and, 
 if the silver be homogeneous," J will " present a beautiful 
 sienna-colored drawing of the original design, produced 
 by a film of the oxychloride§ formed. It is now placed 
 in an open dish, containing a very weak solution of 
 ammonia, and the surface gently rubbed with very soft 
 cotton, until all the deposit is dissolved; as soon as 
 this is effected, it should be instantly removed, and 
 plunged into distilled water, and carefully dried. The 
 
 * This plate must be well varnished on its back and edges. 
 
 f A small portion of varnish is removed from the Daguerreo- 
 type for this purpose. 
 
 J "It is very necessary that the silver of plates subjected to 
 this process be homogeneous. Striae, imperceptible in the 
 original Daguerreotype, are instantly brought out by the 
 nascent anion (or element liberated from the solution at the 
 positive pole) ; probably silver, formed by voltaic precipitation 
 would be found the most advantageous." — Prof. Grove. This 
 extract, illustrated as it was by the condition of the prints from 
 some of the etched plates, indicates that the application of 
 electro-plating, before described (J 137), will eventually be 
 found of some service. 
 
 § Oxygen from the water, and chlorine from the acid, are 
 released at the Daguerreotype plate. 
 
ELECTRO-ETCHING. 
 
 57 
 
 process is now complete, and a perfect etching of the 
 original design will be observed; this, when printed from, 
 gives a positive picture, or one which has its lights and 
 shadows as in nature ; and which is in this respect more 
 correct than the original Daguerreotype, as the sides 
 are not inverted : printing can therefore be directly read ; 
 and in portraits thus taken, the right and left sides of 
 the face are in their proper position." — " There is, how- 
 ever, ex necessitate rei, this difficulty with respect to 
 engravings from Daguerreotypes; if the plates be etched 
 to a depth sufficient to produce a good impression, some 
 of the finer lines of the original must inevitably run into 
 each other; and thus the chief beauty of these exquisite 
 images be destroyed. If, on the other hand, the process 
 be only continued long enough to leave an exact etching 
 of the original design, which can be done to the minu- 
 test perfection, the very cleaning of the plate by the 
 printer destroys its beauty; and the molecules of the 
 printer's ink being larger than the depth of the etchings, 
 a very imperfect impression is produced."* 
 
 159. But though these mechanical difficulties exist 
 with respect to printing from an etched plate, yet the 
 etching is perfect. The action of the liberated elements 
 has produced, perhaps, the most delicate piece of work- 
 manship ever seen ; and though many practical difficul- 
 ties will ever exist against successfully printing from 
 such plates, yet the electrotypist possesses the means 
 of multiplying the most faithfully and elaborately ex- 
 
 * Vide Proceed. Elect. Soc. p. 98. 
 12* 
 
58 
 
 ELECTROTYPE MANIPULATION. 
 
 ecuted among them, with undeviating certainty; and of 
 obtaining in metal as many perfect copies of the original 
 as he may think fit to take. " To give an idea of the 
 perfect accuracy of these, I may mention that in one I 
 have taken/ ' writes Mr. Grove, " on which is a sign- 
 board, measuring on the electrotype plate ^th D y 1 R_ths 
 of an inch, jive lines of inscription can, with a micro- 
 scope, be distinctly read." 
 
 160. I can conceive, therefore, that among those into 
 whose hands these pages may fall, there are many who will 
 value this discovery, which furnishes a means of multi- 
 plying readily these treasures of art, I was about to 
 say ; and possibly art is the fittest designation to give 
 to this process, which has arisen at the magic touch of 
 science. It is true no living artist can produce pencil- 
 lings so true and faithful; but science has called into 
 action the finger of nature, who is ever faithful and ever 
 true; and has inscribed upon her productions, not the 
 words " drawn by Landseer, and engraved by Cousins," 
 but " drawn by Light, and engraved by Electricity."* 
 
 161. M. Fizeau's Process. — M. Fizeau has been most 
 successful in engraving Daguerreotypes. He inserts the 
 plate in a mixture of nitric, nitrous, and hydrochloric 
 acids, by which means the black or silver parts of the 
 picture are eroded : he then washes out the chloride of 
 silver thus formed with ammonia, and again immerses 
 the plate in the acids, repeating the process several times. 
 A certain depth of etching is thus produced. He then 
 
 * Vide Prof. Grove's paper. 
 
ELECTRO-ETCHING. 
 
 59 
 
 rubs linseed oil on the plate, and washes it off, so that 
 the parts in relief may be still exposed ; he now gilds 
 these parts by the electro process, and afterwards re- 
 moves the oil by caustic potash; this being done, he 
 bites in the hollow parts with nitric acid, and so aug- 
 ments the depth at pleasure. Now, as silver would soon 
 wear out in the press, he coats the whole surface with 
 copper by electric deposition, and thus prepares the plate 
 for use; and when one surface of copper commences to 
 wear, he removes it by chemical means, and supplies its 
 place with a fresh deposit. 
 
 162. Neio Mode of Etching. — Dr. Pring has de- 
 scribed* another mode of etching. A polished steel or 
 other metal plate is connected with the positive end of 
 a series of four or five, a good coil of coated copper wire 
 being interposed between the plate and the battery. 
 The other wire, guarded by glass or other insulator, is 
 held in the hand and employed as an etching-tool, when 
 any device may be drawn. The magneto-electric ma- 
 chine will also furnish electricity for this mode. The 
 plate may be reversed and connected with the negative 
 end to vary the experiment. Various wires may be used. 
 No solution is employed ; it is therefore not included in 
 our present art, being mentioned here as a curious fact. 
 
 * Vide Phil. Mag., Aug. 1843. 
 
60 
 
 ELECTROTYPE MANIPULATION. 
 
 IV. APPLICATIONS OF ELECTROTYPE, &c. 
 
 163. Patents. — In reviewing the patents taken out 
 (and there are not a few), I have felt some degree of dif- 
 ficulty in tracing the features by which the right of one 
 is distinct from the right of another ; and have almost 
 doubted whether many of the patents are not based 
 rather upon the nature of the moulds, than of the power 
 employed. To one is allowed the peculiar privilege of 
 making a wax model of a stewpan, and depositing cop- 
 per upon this ; to another, the peculiar right of making 
 the model of a seal by uniting some printer's type, and 
 depositing copper upon this. I shall best succeed in 
 conveying an idea of the extent to which this art has 
 been patented, by extracting from the several specifi- 
 cations the general summaries on which the claims are 
 based. And I doubt not that my readers will be some- 
 what surprised, when they find how the principle of 
 electro-chemical decomposition — for it is but a general 
 principle — has been seized upon and appropriated. 
 
 164. One has accomplished certain " improvements 
 which have for their object the coating or covering 
 manufactured articles composed of wrought or cast iron, 
 lead and copper and its alloys, with copper or nickel ; 
 such coating being effected by means of galvanic elec- 
 tricity." Nor does he " confine himself to any particu- 
 lar arrangement of apparatus, but claims the mode of 
 treating manufactured articles, of the metal and alloys 
 
APPLICATIONS OF ELECTROTYPE. 
 
 61 
 
 above stated, so as to obtain a permanent coating or 
 covering of copper or nickel." 
 
 165. With respect to plating, patentees claim " the 
 use of a solution* of silver, in prussiate of potash,f or 
 other analogous salt, or in pure ammonia, in combina- 
 tion with a galvanic current;" and "the use of a solu- 
 tion of silver in acid, so as to constitute a neutral salt, 
 in connection with a galvanic current ; the articles in 
 this (the latter) case having been previously coated 
 with silver." Under the head of gilding, is claimed 
 "the use of a solution, for the purpose of gilding, formed 
 of oxide of gold, dissolved in prussiate of potash or soda, 
 or any other analogous salt, and combining the action 
 of a galvanic current with the use of a salt of gold as 
 above, preferring the solution of gold formed by dissolving 
 the oxide of gold in prussiate of potash ; and, further, 
 the patentees claim, with reference to the two last heads 
 of their invention, the application of a galvanic current, 
 in combination with solutions of gold or silver for 
 coating or plating with gold or silver, whether the ar- 
 ticles to be so coated are formed entirely of metal or 
 only partly so." 
 
 166. The same parties prepare surfaces of iron to 
 receive a coating of copper or other metal, by connect- 
 ing them with a piece of zinc and placing them in acid, 
 
 * It is stated ' 'that it will be found necessary to add from 
 time to time a fresh supply of the oxide to the solution, in order 
 that it may be kept saturated with that salt." 
 
 f Or rather cyanide of potassium. Vide § 95. 
 
62 
 
 ELECTROTYPE MANIPULATION. 
 
 so as to form a voltaic pair j " after a short time the 
 scales and dirt will fall from the iron, leaving its sur- 
 face perfectly clean and bright and fit to receive a 
 coating of copper, and then one of silver or gold. 
 
 167. The right is claimed of etching on iron or steel 
 by the electrolysis of a solution of common salt, and an 
 iron or steel plate ; on silver, by a solution of sulphate 
 of soda or sulphate of silver, and a silver plate 5 on 
 gold, with hydrochloric acid, and a gold plate ; on cop- 
 per, sulphate of copper and a copper plate ; nor do the 
 patentees limit their claim to the metals named, but 
 " claim the use or application of voltaic electricity for 
 engraving on metals generally f } and hence, I presume, 
 within this comprehensive clause is included the etch- 
 ing of Daguerreotype plates 5 although the latter process 
 was not discovered until months after the patent was 
 enrolled. 
 
 168. Another application of the art is to form rollers 
 of copper for printing or embossing calicoes, &c, by 
 making a model of a roller, and, after rendering it a 
 conductor by any of the ordinary means, depositing cop- 
 per upon it j* also for thickening old cylinders, rollers, 
 &c, for the same purpose ; and for filling up portions 
 of patterns that are to be obliterated. 
 
 169. Other applications of this process are described : 
 " 1st, in the production of a printing, embossing, or 
 impressing metallic cylinder, plate, or block, having a 
 
 * This is merely a variation in the form of the mould.' — 
 « 163.) 
 
APPLICATIONS OF ELECTROTYPE. 
 
 63 
 
 device or pattern formed thereon, suitable for the above 
 purposes; such device or pattern constituting one per- 
 feet or connected design, produced from an originally 
 engraved or otherwise executed portion of the said 
 design ; 2d, in a mode of joining together engraved 
 or otherwise executed metallic plates, so as to form one 
 connected surface; 3d, in obtaining an extended plain 
 surface to an engraved metallic plate, whereon a contin- 
 uation of, or an addition to, the subject already formed 
 may be engraved ; 4th, in certain modes of producing 
 suitable surfaces, as aforesaid, such modes not requiring 
 the ordinary original process of engraving;* 5th, in a 
 mode of producing surfaces, as aforesaid, such surfaces 
 being suitable for printing, or printing or embossing in 
 various colors ;f 6th, in the application and use of dies, 
 formed by the agency of voltaic electricity, for the pur- 
 pose of embossing or impressing horn, hoof, or tortoise- 
 shell, in the manufacture of buttons ; 7th, in the mode 
 of mounting or attaching seals, bookbinders' tools, 
 
 * A flat metal surface is covered with varnish ; the design 
 is traced by removing the varnish ; the whole is then covered 
 with plumbago (§ 39), or rendered conductible by other means ; 
 and is placed as a mould in connection with the battery ; or a 
 lithographic stone is prepared and treated in a similar manner; 
 or the design is punched in sheet-lead, and this is united to 
 other metal, and then deposited upon. 
 
 f Two or more moulds, according to the number of colors, 
 are obtained from the same original ; and from each are re- 
 moved those portions which are not to be printed by the color 
 to which it will be confined. 
 
64 
 
 ELECTROTYPE MANIPULATION. 
 
 or other such instruments used for impressing, such 
 instruments or tools being produced by the agency 
 aforesaid ; and, lastly, in a mode of producing seals for 
 impressing on wax or other such substances." 
 
 170. The object of another " invention is to produce 
 pipes, boilers, stewpans, or other vessels of copper, 
 through the agency of voltaic electricity," by depo- 
 siting copper on moulds of " clay, wax, plaster, or 
 other like substances ; or of lead or other metal, fusible 
 at a lower temperature than copper." Another part of 
 the invention relates to the joining together of several 
 pieces, so as to form vessels ; and by which means stop- 
 cocks, or other such parts, may be added to boilers, &c, 
 formed by the above process." 
 
 171. The above is by no means a complete abstract 
 of patents, as our readers will have themselves dis- 
 covered from many other processes that have been pre- 
 sented to them in the course of this work. But we 
 must devote the space that remains, to a few subjects 
 that have not a place elsewhere. 
 
 172. In the preceding pages, I have dwelt on the 
 copying of medals and plaster medallions alone. 
 Enough, however, has been said to render the subject 
 familiar, and to enable those who are successful in copy- 
 ing the small objects here treated of, to carry their ex- 
 periments to any extent. Busts, statues, vases, may, 
 by proper application of the principles laid down, be as 
 readily coated with copper as the small wax moulds 
 (§ 32). Yea, almost anything, to which a coating of 
 plumbago can be given, may serve as a mould on which 
 
CONCLUSION. 
 
 65 
 
 to deposit the metal. Gutta percha, a new gum, which 
 becomes plastic at less than 212° Fahrenheit, and hard- 
 ens on cooling, will be often found a most convenient 
 material for moulds (§42). With no credit to my discern- 
 ment, I could devise a thousand instances in which this art 
 might be available in the common concerns of life ; but I 
 had rather leave the merit to him who shall actually in- 
 troduce it into these several spheres. It may be found 
 available in protecting from the effects of weather the 
 busts and statues which are introduced in ornamental 
 gardening, and which are often, for the sake of eco- 
 nomy, made of plaster of Paris. They may be saturated, 
 as described elsewhere (§ 40), covered with plumbago 
 (§ 32), and placed within a large vessel whose sides are 
 covered with copper, and then by means which must 
 now be familiar to the reader, a deposition of cop- 
 per may be formed" on them : this can be bronzed by 
 the simple application of the black-lead brush ; and thus 
 a sightly and permanent exterior will be produced. — 
 By the same means small and valuable wax figures may 
 be preserved \ the surfaces of these are of themselves 
 very liable to crack, and fall off in chips. A thin cov- 
 ering of copper, without in the least degree affecting 
 the fineness of the workmanship, will preserve it. Busts 
 and statues may be made in solid electrotype metal, by 
 first coating a bust with thin copper, then embedding 
 the whole in plaster or cement, afterwards breaking 
 away the original bust, and finally making the mould 
 that remains serve as a decomposition cell. 
 
 173. Electro-tint, or Galvanography. — Another 
 13 
 
66 
 
 ELECTROTYPE MANIPULATION. 
 
 form of deposit has been termed electro -tint. It con- 
 sists in painting on white metal with etching-ground or 
 varnish : the several shades are obtained by the relative 
 thickness of the layers of varnish; the whole is then plum- 
 bagoed; and the deposit obtained on it is used as a plate 
 to furnish prints. Prof. Von Kobell, after obtaining a 
 plate, examines a proof; and if too faint, he makes a 
 mould of the plate; and having obtained a deposit, 
 which will be similar to the original painted plate, he 
 puts varnish on the parts which gave impressions too 
 pale, and obtains a second deposit on this, which when 
 removed will give prints of a better character. 
 
 174. Engraved copper plates may be readily multi- 
 plied by electrotype. The battery must be in proportion 
 to the size of the plate, and the plate must be used in 
 lieu of the moulds. Sometimes the copper deposit will 
 adhere so strongly as to resist all attempts to remove it. 
 This may be prevented by a very easy process. — Before 
 the plate is used, heat it and rub beeswax over the sur- 
 face; continue the heat, and by the application of soft 
 cotton, rub it perfectly clean from the wax ; or the plate 
 may be rubbed with black-lead in lieu of wax. In either 
 case it may then be used without fear of adhesion. The 
 deposit obtained on it is to be removed, and used as a 
 mould, from which many copies may be taken, equal, in 
 all points, to the original. The engraved plates of the 
 recent Survey of London are being thus multiplied. — 
 Sometimes moulds of medals and casts are made from 
 originals in electrotype copper. 
 
 175. Glyphography is another application. A smooth 
 
CONCLUSION. 
 
 67 
 
 copper plate is blackened by sulphuret of potassium, 
 and is then coated with an etching-ground, through 
 which a design is traced. The high lights are now 
 built up of non-conducting materials, so as to prevent 
 their printing- the whole is coated with plumbago, 
 and an electro-copper plate is formed from it : the cop- 
 per plate is afterwards soldered on a block of wood, and 
 is used as a wood-cut; it is called an electro-glyphogra- 
 phic cast Or this plate, after etching, has a plaster- 
 cast taken from it, and from this the high lights are cut 
 out ; it is then oiled, and a second cast is taken, from 
 which a stereotype copy is to be made. This is called a 
 stereo-glyphographic cast. 
 
 176. Metallic Cloth is prepared by Messrs. Elking- 
 tons, for various purposes. On a surface of copper is 
 attached very evenly stout linen, cotton, or woollen cloth; 
 the copper is placed in a solution of copper, or other 
 metal, and is connected with the negative pole of the 
 battery : a sheet of copper, or other metal, as the case 
 may be, is placed opposite, and in connection with the 
 positive pole of a battery. Decomposition takes place, 
 and the metal, in endeavoring to reach the metal plate, 
 insinuates itself into the interstices of the cloth, and 
 forms a perfect metallic sheet. 
 
 177. Purity of Sulphuric Acid. — As the great object 
 of writing this treatise is to simplify the various stages 
 of the process, I must not leave unnoticed a fact that 
 has been pressed upon my attention, one which is of 
 great practical importance — the necessity of employing 
 pure sulphuric acid; I mean, so far pure as to be free 
 
68 
 
 ELECTROTYPE MANIPULATION. 
 
 from nitric acid. Very commonly a small portion of 
 nitric acid is present, and this operates in a most de- 
 structive manner upon the zinc, defying all care and 
 trouble in amalgamation ; for it attacks some of the 
 mercury, and leaves portions of the zinc exposed, giving 
 rise to an amount of local action to no trifling extent ; 
 indeed, it is the serious objection to the use of the plati- 
 nized battery; and has caused it to be rejected by many 
 manipulators. This will explain the cause of amalgama- 
 tion's failing, far more effectually than the assumption 
 of the impurity of the zinc. The latter is well con- 
 cealed by the mercury ; but the nitric acid undermines 
 the other precautionary means, and militates most effect- 
 ually against the permanent preservation of the zinc. 
 
 178. Test for Nitric in Sulphuric Acid. — The presence 
 of nitric acid may be determined by the following 
 simple and effectual test : Apply heat to a Florence 
 flask, containing sulphuric acid, with which has been 
 mixed some sulphate of indigo; should the blue color 
 disappear, nitric acid is present ; should it remain, the 
 acid is good and fit for use. — Besides exciting the bat- 
 teries with the pure acid, it is also requisite to employ 
 the same acid in the process of amalgamation. When 
 these precautions are taken, the common rolled or cast 
 zinc may be employed with impunity, and a perfect 
 action will be obtained. It is rather a difficult matter 
 to get rid of the nitric acid. 
 
 179. In reference to electrotype medals and other 
 works of art produced in moulds taken from the ori- 
 ginals, it may be as well to remark that there are two 
 
CONCLUSION. 
 
 GO 
 
 methods of giving them a silver or a gold surface by 
 electric deposition ; either by making the medal ac- 
 cording to the instructions given in the First Part of 
 this work, and then gilding or plating it ) or by pre- 
 paring a good and clean mould (§ 28), and depositing 
 in it a certain quantity of silver or gold, and then back- 
 ing it up by the deposition of copper. The best elec- 
 trotype medals are produced in this way. 
 
 180. Copying Busts, &c. — It may not be out of place 
 to add here the method pursued for copying busts or 
 statues from wax originals. The original is covered 
 in the usual way (§ 32) with plumbago ; it is then 
 placed in the copper solution of a decomposition cell 
 (§ 56), and is acted on until a moderate coat of copper 
 is obtained ; it is now removed and embedded in plaster 
 of Paris \ the wax is melted out, and the interior well 
 cleaned with a hot lye of potash or soda. It is then 
 inverted, and filled with a solution of the metal which 
 is to be deposited ; and in the solution is placed a sheet 
 of the same metal, as in the ordinary arrangements. 
 The theory of this operation is self-evident; but in 
 practice, especially on small articles, a difficulty pre- 
 sents itself, to guard against which requires no little 
 care. The action occasionally ceases without any ap- 
 parent cause ; and for days, although all things seem in 
 order, no appreciable deposit takes place. This can 
 only be obviated by cleaning the positive metal and 
 greatly reducing the action. The effect is due to phe- 
 nomena too complex to be detailed in the present 
 treatise. 
 
 13* 
 
70 
 
 ELECTROTYPE MANIPULATION. 
 
 181. It is very gratifying to observe the late import- 
 ant applications of the art that have been made by the 
 Elkingtons. Dr. Braun has been for some years in 
 Italy, and has obtained electrotype moulds from casts of 
 some of the finest sculptures ; these moulds are now the 
 property of Messrs. Elkington, who intend to publish 
 copies obtained by their means ; and not only so, their 
 intention is also to multiply the choice works of modern 
 artists by similar means; and thus to place within the 
 reach of the man of taste, at a comparatively moderate 
 cost, faithful representations of the choicest works of 
 the chisel, which could not otherwise be obtained ex- 
 cept at great cost, and in the majority of instances 
 could not be obtained at all. 
 
 The Messrs. Elkington have already commenced 
 publishing, on a reduced scale, genuine copies of por- 
 traits of the men of classic antiquity, the moulds of 
 which have been obtained from the Museo Borbonico, 
 at Naples, and from the Lateran Museum. 
 
 182. I have not space to make any lengthened com- 
 ments upon the extensive applications of electrotype. 
 I can fancy that scarcely one will read this treatise with 
 attention, and reflect on the uses to which the art has 
 been applied, without figuring to himself many others to 
 which it may be applied. The science on which the 
 whole of what we have treated is based, reminds one of 
 that little cloud, dimly seen at first in the distance, no 
 bigger than a man's hand, which gradually develops 
 itself until it enfolds within its spacious mantle the 
 whole of the visible face of nature. Every day is 
 
CONCLUSION. 
 
 71 
 
 bringing fresh evidence of the vast extent of the opera- 
 tions of electricity ; although each fresh acquisition of 
 knowledge only teaches us how little we really know. 
 Scarcely do we elucidate one series of problems, than 
 another, and another, and another, presents itself to our 
 earnest gaze ; and we are compelled, in summing up the 
 results of even our most successful labors, to confess, 
 with the great philosopher, that we are like children on 
 the sea-shore, who pick up occasionally one pebble of 
 greater value than the rest. 
 
 CHARLES V. WALKER. 
 
 Dec. 1,1849. 
 
INDEX. 
 
 Affinity for oxygen of positive copper, § 94. 
 Alkaline detergent solutions, \ 119. 
 Alloys, reduction of, \ 139. 
 Amalgamation to promote adhesion, \ 121. 
 Applications of electro-gilding, \ 135. 
 
 Black oxide developed in streaks, \ 107. 
 
 Brass, deposition of, f 139. 
 
 Bronze reduced, \ 139, 
 
 Busts, mode of copying, \ 180. 
 
 Button-dies, manufacture of, \ 169. 
 
 Cleaning electro-plate, § 123. 
 Cleansing, great importance of, §116. 
 Cleansing by the dry method, g 118. 
 Cleansing by the wet method, $ 119. 
 Coating metals with copper and nickel, £ 164. 
 Colors, blocks for printing, produced, $ 169. 
 Cyanide of potassium, electrolysis of, \ 94. 
 preparation of, \ 95. 
 
 Daguerreotype, electro-etching of, $ 153. 
 
 pictures, nature of, \ 155. 
 
 protected by electro-gilding, \ 136. 
 
 plates, I 137. 
 
74 
 
 INDEX. 
 
 Electro-etching, § 149. 
 Electro-etching, new mode of, \ 162. 
 Electro-extension of plates, &c, \ 169. 
 Electro-gilding, first case of, § 92. 
 Electrolytic action, principles of, § 94. 
 
 copies of Daguerreotypes, \ 137. 
 
 Electro-plating, early instance of, \ 92. 
 Electro-tint, \ 173. 
 Electro-uniting of boilers, &c, \ 170. 
 Electro-uniting of plates, &c, \ 169. 
 Engraving, manual labor of, saved, \ 169. 
 Etching-ground of gold, \ 135. 
 plates, patent for, \ 167. 
 
 Film of air on all bodies, \ 120. 
 
 Fused compounds electrolyzed, \\ 140, 142. 
 
 Galvanography, \ 173. 
 Gilding by a single cell, | 108. 
 
 battery process, § 111. 
 
 patent for, g 165. 
 
 Gilding-wax, \ 124. 
 
 Gilding with the battery, advantages of, \ 110. 
 Gold solution, composition of, \ 99. 
 Gutta-percha moulds, \ 172. 
 
 Heat for preparing metallic surfaces, $ 114. 
 Homogeneity of silver, how to obtain, $ 158, note. 
 Hydrochloric acid, electrolysis of, § 158. 
 Hydrogen adheres to plates, \ 156. 
 
 Iron surfaces cleaned by voltaic action, \ 166. 
 
 Lead, deposition of, \ 128. 
 
INDEX. 
 
 Magneto-electro plating, § 144. 
 
 Metallic cloth, § 176. 
 
 Metallic solutions, various, § 125, &c. 
 
 Metallo-chromes, $ 145. 
 
 Motion to articles while plating, \ 115. 
 
 Nitrate of silver, experiment with, § 92. 
 
 Nitric acid, &c, for preparing metallic surfaces, \ 119. 
 
 , test for, I 178. 
 
 Ore, reduction of, H 141, 143. 
 Oxide of lead deposited, g 147. 
 Oxide of iron deposited, \ 148. 
 Oxides of silver and gold, \\ 97, 99. 
 
 Patents, summary of, § 163, &c. 
 
 Patterns for printing, &c, produced, $ 169. 
 
 Platinating, \\ 128, 129. 
 
 Plating by single cell process, § 106. 
 
 the battery process, § 111. 
 
 , patent for, J 165. 
 
 Primary results, definition of, § 94. 
 Purity of sulphuric acid, \ 177. 
 
 Relation in size between plates of elementary pairs, $ 157. 
 
 Salts of gold and silver easily decomposed, g 104. 
 
 Sawdust, hot, for drying cleaned articles, \ 120. 
 
 Scratch-brush, its value, \ 121. 
 
 Seals, mounting by electrotype, g 169. 
 
 Secondary results, nature of, f 94. 
 
 Secondary current, \ 112. 
 
 Silver solution, composition of, \ 96. 
 
 Single cell, flat, for gilding, &c, \ 105. 
 
 Size of generating pairs in relation to electrodes, $ 157. 
 
76 
 
 INDEX. 
 
 Soap-bubble, J 146, note. 
 Statues, mode of copying, J 180. 
 
 Tarnished silver, mode of cleaning, \ 123. 
 Theory of electrolysis, § 94, &c. 
 Thin wire for retarding the action, § 106, note. 
 Tin, deposition of, \ 128. 
 
 Union between copper and gold or silver, mode of producing, 
 I 116, &c. 
 
 Vessels of capacity formed, \ 170. 
 Voltaic condenser, § 112. 
 Voltaic governor, § 107. 
 
 Whole designs produced by the electro-union of parts, $ 169. 
 Zinc, deposition of, \\ 128, 138. 
 
 THE END. 
 
PUBLICATIONS 
 
 OF 
 
 HENRY CAREY BAIRD, 
 
 SUCCESSOR TO E. L. CAREY, 
 
 No. 7 Hart's Building, Sixth Street above Chestnut, Philadelphia. 
 
 SCIENTIFIC AND PRACTICAL. 
 
 THE PRACTICAL MODEL CALCULATOR, 
 
 For the Engineer, Machinist, Manufacturer of Engine Work, 
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 six hundred pages. 
 
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2 
 
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 THE PRACTICAL METAL-WORKER'S ASSISTANT, 
 
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3 
 
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4 
 
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5 
 
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 1* 
 
0 
 
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8 
 
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9 
 
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10 
 
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11 
 
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12 
 
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13 
 
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