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SAMSON net i/- CROSBY LOCKWOOD & SON, 7, Stationers' Hall Court, E.G. 3-/3HO ELECTRO - TYPING A PRACTICAL MANUAL FORMING A NEW AND SYSTEMATIC GUIDE TO THE REPRODUCTION AND MULTIPLICATION OF PRINTING SURFACES AND WORKS OF ART BY THE ELECTRO- DEPOSITION OF METALS BY f. W. URQUHART, C.E. AUTHOR OF "ELECTRO-PLATING, A PRACTICAL HANDBOOK," "ELECTRIC LIGHT, ITS PRODUCTION AND USE," &C. LONDON CROSBY LOCKVVOOD AND CO. 7, STATIONERS' HALL COURT, LUDGATE HILL 1881 [All rights reserved} V. ' tt PRINTED BY WILLIAM CLOWES AND SONS, LIMITED LONDON AND BECCLBS. PREFACE. THE author's endeavour to treat, in an easily appre hended style, upon another branch of the Electro- metallurgic art ("Electro-Plating"), has received so much encouragement that he has been induced to offer the present handbook as a companion volume, in the belief that it will meet a want of considerable extent. The distinct art of electro-typing has, within the last few years, advanced with such wonderful rapidity that it is now practised as an important auxiliary in industries of the most varied descrip- tion. The particular methods employed in the processes ten years ago may now be considered in great part obsolete, improved systems having superseded them. This small treatise is therefore intended to serve as a guide, not only to beginners in the art, but to those who still practise the old and imperfect methods of electro-typing ; it aims also at preparing the way for a thorough scientific study of the art, if such be considered necessary for its successful prosecution. VI PREFACE. The introduction of cheaper electrical generators, in the form of dynamo-electric machines, driven by steam-power, has brought about many of the changes above alluded to. The Americans have exhibited great enterprise of late years in cheapen- ing every detail of the process, which English electrotypers have not been slow to appreciate, adding to both speed of working and excellence of the products ; but on the Continent, especially in Germany, the art is as yet in a backward state. In the following pages special prominence has been given to the production of printing electro- types, and to the reproduction of art work. An endeavour has been made to grasp the fundamental principles of the art ; an earnest attempt has been made to induce the reader to take some interest in the scientific basis of the processes, by giving practical examples of the use he can make of the oft-misunderstood and generally confusing laws of electro-chemical science. The first chapter of the book is in great part occupied by explanations of the leading electrical laws, and their relation to the chemical compounds to be subjected to electrolysis. An endeavour has been made to reduce the terms, "current of electricity," " amount of deposit," and so forth, to some real and easily apprehended meaning, in order that the reader may be able to attach prac- tical significance to the current he is using, and reconcile its amount with the weight of copper he can obtain. Some little acquaintance with chemistry PREFACE. vii on the reader's part has been assumed, but of elec- tricity he is supposed to know little or nothing ; he will, however, derive great benefit from a careful perusal of the electrical laws in some good text-book. The second and following chapters of the work are devoted to instructions to the operator, with a special bearing upon ordinary requirements. The use of the dynamo-electric machine is explained at length. The description of apparatus employed by the electrotyper has received careful attention ; the materials now usually found best suited to the different sections of the art are described ; the preparation of work for the depositing process is treated at considerable length, and the process itself has been carefully detailed in Chapter VIII. The work is thus arranged in ten chapters, one division being devoted to each important section of the art : the divisional paragraphs, when they open a new portion of the subject, are furnished with italicised headings. LONDON, 1881. CHAPTER 1. PAGB Introduction to the Art .... 130 CHAPTER II. Metals used by Electrotypers . . 31 38 CHAPTER III. The Source of Electricity . . . 39 98 CHAPTER IV. The Solutions ..... 99 117 CHAPTER V. Depositing and Moulding Apparatus . 118 140 CHAPTER VI. Moulding Materials . . . 141 151 X CONTENTS. CHAPTER VII. PACK Preparation of the Work . . 152 178 CHAPTER VIII. The Depositing Process . . . 179 204 CHAPTER IX. Hard Facings for Electrotypes . . 205 2 1 1 CHAPTER X. Final Preparation of the Work . 212^22 ELECTRO-TYPING. CHAPTER L Introduction to the Art. THE electro-depositor's art is so widely dissemi- nated over numerous modern industries, that to give a concise and comprehensive definition of the compound term electro-typing is rather diffi- cult. Its general significance, however, may be understood to imply the production of metallic copies and duplicates of objects by means of electricity. Thus, an electrotype of a wood engraving con- sists of a metallic duplicate, accurate in every detail. It possesses the additional advantage of being better adapted to printing purposes than the original. An electrotype of a plaster bust, or a bird, or a fish, forms an accurate metallic reproduction of the original, rigid, and indeed everlasting. In some important respects the products of this fascinating and beautiful art resemble the results of photography ; every line, excellent fea- B 2 ELECTRO-TYPING. ture and defect, is reproduced with a faithfulness almost surpassing belief. From the nearly invisible lines of the finest steel engraving to the boldest contour of a statue, the electrotype is throughout an exact and unmistakable reproduction. Copper is the metal almost universally employed in the production of electrotypes. It is cheap, ductile, strong, and flexible, and is admirably adapted for printing purposes in many cases where various other metals and wood are inad- missible. It also presents an agreeable and attrac- tive appearance in art reproductions. Electro- typed printing surfaces may be, and frequently are, so protected from the effects of wear, by means of a thin and hard facing of iron, brass, or nickel, that they may be made to yield as many as from ten to twenty thousand impressions. The " steel face," or its remains, may, moreover, be dissolved off, and the process repeated without loss of sharpness or injury to the original ; in this manner the printing electrotype may be made infinitely more useful than the prototype itself. Engraved steel plates are not now, owing to their great value, used generally in printing; electrotypes, steel-faced, are taken of them and employed in the printing process. Wood blocks of value are similarly treated. Set-up type is fre- quently in Europe, and almost universally in America, copied in electrotype, instead of by means of stereotyping, the old casting process. Any number of copies of one object or plate, either INTRODUCTION. 3 from the original or from an electrotype, can be obtained. Bank-notes, postage stamps, bill-heads, illustrated newspapers, playing cards, grocers' wrapping papers, maps, and numerous other kinds of printing work are executed from electrotype plates. In the domain of art the applications of the electrotype are no less widespread. It is employed to produce copies of the smallest medals, casts, and coins ; its application to the production of gigantic statues and ornaments may be inspected in almost every public recreation ground ; and in great per- fection on the celebrated Albert Memorial, in Hyde Park. It is almost impossible, and its ac- complishment would prove of little use, to detail the numberless applications of the art ; they are legion, and may be said to be enormously aug- mented in numbers yearly. Having thus obtained an outline conception of the field in which the electro-typer's art is utilised, it will prove instructive to briefly ex- amine the main manipulatory features and forcea necessarily employed in its general practice. It will be well to premise, however, that electro- typing and electro-plating are very closely re- lated to each other; indeed, one is often classed with the other. They are both deposits of metals laid in position by means of electricity, but except in this main particular their application lies in totally different fields. To electro-plate is to dis- guise with an adherent thin coating of metal, which 4 ELECTRO-TYPING. then serves as an ornamental covering to the object treated. To electrotype, on the other hand, is to produce a separate and distinct object, with an existence of its own. The following 26 pages are exclusively devoted to a comprehensive discussion of the chief conditions under which the electro- depositor's art is practised. This section of the work is -intended to serve as an introductory lesson, in which the fundamental laws of the science, as applicable specially to the production of electrotypes, are laid down and defined. It will well repay the student to give it careful attention, with reference, where necessary, to works on elec- tricity ; no difficulty will afterwards be encoun- tered, because the remaining chapters refer chiefly to the apparatus and manipulation by means of which these primary principles are utilised. A condensed outline of the Art. This must be accepted merely as an outline sketch, to assist the reader to a more intelligent understanding of the principles laid down further on. Let us, for ex- ample, select an engraved block from which an electrotype is required. The block is first rubbed gently all over its surface with finely powdered plumbago, which gives a polish and prevents " seizing " in the moulding process ; and it is afterwards blown upon with the breath to free it from dust. A frame of sufficient size is now filled up level with a hot melted mixture of the following ingredients : Bees'-wax, Venice turpentine, and blacklead. This is to form the mould, which is INTRODUCTION. 5 placed directly over the wood block on the level table of a press, when both are forced together with considerable pressure. A little care will now enable the mould and block to be separated. The mould contains a perfect copy of the block reversed. The next process has for its object the provision of a conducting surface for the mould, so that it may conduct the current of electricity sufficiently well to allow of deposition being proceeded with. This is done by carefully brushing plumbago over its surface with soft brushes until a uniform polished film is produced ; this conducting surface is so spread as to allow of the copper being de- posited all over the mould. Those portions which should not receive a deposit are " blocked out " by varnish. The mould is now hung in a vessel containing an acidulated solution of sulphate of copper. A wire from the negative pole of a gal- vanic battery is attached to it, while the positive pole is connected with a copper plate, termed the anode. Deposition of copper upon the mould immediately commences, beginning at the edges and advancing towards the centre. When a sufficient thickness of "shell" is obtained, which may take a few days to accomplish, the mould is removed, heated, and separated from the " shell." The surface of this electro-deposit is found to be in every respect a duplicate of the original block, but it is yet too weak for printing purposes. It is tinned and backed with a layer of an alloy of lead and tin, squared, ELECTRO-TYPING. planed flat, and finally mounted upon a wooden block, type high. It may now be printed from. Such is the mere routine of the process, as applicable to common wood blocks, which would not prove of material assistance to the reader were he to try the experiment and ignore the details upon which the success of the operation mainly depends. To gain a mastery over the principles of the art, the reader must devote his earnest attention to obtain a correct understanding of the action electri- city exhibits in its operation ; he should also be acquainted with the best methods by which electri- city may be obtained ; and must particularly be familiar with the use of currents and the mani- pulation of galvanic apparatus. The different processes of moulding and preparing he will find comparatively easy, which may also be said of the final preparatory or finishing process. Each im- portant section of the entire process will be found under the different heads, as complete as possible in itself, the more important being dis- cussed first. A slight knowledge of chemistry on the part of the reader will prove of much assist- ance. Nomenclature of the Art. The fundamental principle of electro-deposition may be laid down as follows : When a current of electricity passes through a solution, as of cupric sulphate, it pro- duces a chemical change-, the solution is decomposed, and the copper set free. This will be more fully INTRODUCTION. 7 explained hereafter ; at present we are concerned with the terms employed to indicate the nature of the conditions necessary in electro-chemical de- composition. The nomenclature Faraday employed is as follows : Electrolysis (from elektron, and lysis, a disengaging) is used to designate that branch of electrical science which treats of tjie laws ot electro-chemical decomposition ; it includes, of course, the science of electro-metallurgy. A sub- stance capable of being decomposed by a current of electricity is called an Electrolyte (that which is ^mbound by electricity). The poles, or wires and plates, by which the current enters and leaves the solution are called Electrodes (from hodos y away). The positive pole (+), or that by which the cur- rent enters the solution, is termed the Anode (ana, up, and hodos, a way). The negative pole ( ), or that by which the current leaves the solution, is called the Cathode (kata, down, and hodos, a way). The elements of the solution (electrolyte) set free by the current are termed Ions (from ton, going). Those of the elements which appear at the anode are called AnionSy and those set free at the cathode are called Cations. The word electrolyse signifies to decom- pose by means of a current of electricity. The Electric Circuit. Apart from any knowledge of the battery by which the electric current is pro- duced, it should be clearly established in the student's mind that the current must, from its nature, always move in a circuit ; this signifies that no electricity can pass through a wire or other 8 ELECTRO-TYPING. conductor which does not offer a complete and unbroken path. By some the word circuit is taken to signify that electricity which leaves a battery must always have a path provided for its return to the battery. The fact is, that no electrical effects can be obtained in a circuit which is incomplete. Conductors and Insulators. The properties of all classes of conductors and insulators cannot be dis- cussed here, so that we may select those employed in the art of electro-typing for special treatment. All metals are conductors of electricity. Silver offers least resistance to the passage of electricity, and is, therefore, the best conductor. Copper is the next best conductor, and is universally employed for lead- ing wires from the battery to the depositing vessel. Most solutions and acids are conductors, but offer con- siderable resistance to the current. Acidulated water conducts better than pure water. Dry wood, glass, porcelain, gutta-percha, and, indeed, all such non- metallic substances, offer such high resistance to the current that none of it will pass ; these substances are therefore termed insulators. The resistance of a conductor to the current varies directly as its length ; hence, six feet of a particular wire will offer twice the resistance given by three feet. The unit of re- sistance (by which it is measured) may be roughly taken as about equal to six feet of No. 36 Birming- ham wire gauge pure copper wire and is called the Ohm, from Ohm, the German physicist. It is further spoken of in the section devoted to Measure- ment. INTRODUCTION. 9 Current of Electricity. This means the amount or quantity of electricity actually supposed to be pass- ing in a circuit. It implies, in fact, the working power of the electric influence, or its power to deposit a given amount of copper in a given time. A weak current may deposit copper at the rate of five grains per hour only. A strong current may deposit as many ounces in the same time. The unit of current or quantity is termed the Farad or Weber per second. It will deposit in a circuit of one ohm about seven- teen grains of copper per hour. It is also known as a " Veber." Electro-motive Force. The electro- motive force of a current means that power by virtue of which it can surmount resistance. A current of low electro- motive force may be entirely stopped or absorbed by a moderate resistance. A current of high electro-motive force can overcome high resistance, or accomplish work in such a circuit. The full meaning of the term will be better understood a little further on, but it should be stated here that the extent of the electro-motive force or tension of a current depends upon the chemical affinity between the plates and solutions of the battery, and also upon the difference between the elements of the battery. The electro-motive force depends to a great extent upon the electrical relationship exist- ing between the plates. Tables of the electro- chemical series are to be found in most text-books, but they generally ignore the fact that, except in dilute acid, the relationships are apt to be 10 ELECTRO-TYPING. reversed. The following list, including the com- mon metals likely to be used in voltaic cells, exhibits the most electro-positive elements first, and the most electro-negative last. Thus, to obtain the most powerful electro-motive force the first and last elements should be combined in the cell. The further they are apart in the list the higher the electro-motive force. The unit of electro-motive force is called a Volt. Electro-Positive +. Potassium Platinum Sodium Gold Magnesium Hydrogen Zinc Antimony Iron Carbon Aluminium Phosphorus Lead Iodine Tin Chlorine Bismuth Nitrogen Copper Sulphur Silver Oxygen Mercury Electro-Negative . Battery. The word battery here signifies that ar- rangement which in a circuit gives rise to a current. It is the generator of electricity, and is variously styled galvanic and voltaic battery. It may be as- sumed for the present to be the only generator used ; its various forms are fully described in Chap. III. When a pair of plates (of copper and zinc), not touching one another, are plunged in acidulated water, bubbles of gas arise from the naked surface of the zinc plate. When, however, the plates are connected together by a wire, the numerous bubbles of hydrogen are found to arise from the copper INTRODUCTION. II plate, and this goes on until the wire is separated from one of the plates, or the circuit is otherwise broken. A current of electricity circulates, in fact, throughout the series. While the action lasts the zinc plate is being slowly dissolved, but the copper plate remains unaffected. The current is assumed to be set free at the sur- face of the zinc plate ; it moves through the liquid towards the copper plate, and in doing so sets the hydrogen gas free at that plate. The oxygen combines with the zinc and forms sul- phate of zinc. The course of the current is assumed to be starting from the zinc plate, it passes through the liquid to the copper plate, and from its extremity by the wire to the zinc plate again (Fig. i.) If the wire be cut the current ceases to flow. The Simple Vo itaic Generator. zinc plate, being the active element, is termed the positive plate or element of the cell. The copper plate, being passive, is termed the negative element. The end of the plate at which the current leaves the cell is called the positive pole, while the end of the plate by which it enters is termed the negative pole. Thus the extremity of the copper plate forms the positive pole, while the zinc forms the negative one. Of course these terms apply equally to any wires attached to the plates. The end of the wire from 12 ELECTRO-TYPING. the copper or negative plate is always known as the positive pole, and vice versa. These are the fundamental principles of a simple galvanic cell ; their full significance must be sought in text-books of electricity devoted mainly to the subject. Enough is given here to enable the reader to understand and act upon that which follows. The strength of current given by a zinc-copper cell is from various causes low. It is strong at first, but the rapid covering of the copper plate by bubbles of hydrogen and other causes soon brings its force down to a mere fraction of the first rush. Various other generators are in practical use, which yield a constant and powerful current. These will be found described under the heading " Source of Electricity." One cell is a rather weak arrange- ment. Two or more cells may be so joined to- gether as to act in concert. When we have more than one cell the arrangement is called a battery, but the word battery is generally used through- out this treatise, although one cell cannot properly be so termed. The way in which cells may be joined together to form a battery will be found described under "Source of Electricity," but we may briefly examine the effect of connecting two cells to- gether in this place. When the zinc of one cell is connected to the copper of another cell, they form a battery of two cells. The electrodes ot conductors are in this case to be joined to the remaining zinc (negative) and copper (positive) INTRODUCTION. 13 poles. The wires may be simply soldered to the plates, twisted around them, or fastened in binding screws soldered to the plates. It must be particu- larly observed that in forming any electrical connec- tions the wire extremities should be perfectly clean a coating of oxide greatly retards the current. When the two cells are thus connected together it is said that they are joined or combined for electro-motive force, because both their electro- motive forces are added together, and it would be found that two cells thus connected could deposit copper, or do other work, in a much greater resist- ance than one cell could overcome. The quantity of electricity actually passing will remain as for one cell, but the power to push that quantity through a resisting medium has been doubled. Another statement, connected with these cells, should be made here ; it is that each cell offers a given resistance to its own current. It is of much importance to understand this. The liquid be- tween the plates is but a poor conductor, and therefore offers resistance to the passage of the electricity given off at the zinc plate. This resist- ance is called the internal resistance, because it is within the cell, and not between its poles without. Every cell has its internal resistance. Two cells added together present a double measure of in- ternal resistance, and can for that reason give a current in a higher resistance than one cell. When the cell is small, its resistance is great, but dimi- nishes directly as its size is increased. Thus a 1 4 ELECTRO-TYPING. cell of what is known as " quart size " will present an internal resistance twice as great as one ol two-quart size, and so on. The current will also increase in proportion in an interpolar resistance equal to that of the cell. Hence, to obtain the maximum current, or effect, a cell can give, the external should equal the internal resistance. The electro-motive force has been mentioned before, but it remains to be shown that it is not dependent upon the size of cell. A pair of thin copper and zinc wires immersed in the solution will exhibit the same electro-motive force as a pair of plates a yard square. The work power or current will, of course, be very different. Electrodes. These are the conductors which lead the current from the battery to the depositing vessel. The positive electrode, as has been explained, is always that which leads from the negative //#/23< _ExampieofaBustMouid', j , T j exhibiting Leading Wires. should be employed to lead the deposit first to the more remote corners and recesses of the mould (Fig. 24). Air bubbles must be expelled, if they form, by disturbing the solu- ELECTRO-TYPING. tion, or gently rubbing over the surface with a camel-hair brush. Frames of conducting material should be arranged to surround the mould, and effect an equal distribution of the negative pole. Hints. Care must be taken not to stop all Fig. 24. Example of an Art Mould, showing Leading Wires. chance of deposit, by allowing the anode by acci- dent to touch any part of the mould or negative system. The same care must be devoted to avoid bad contacts and points weak in conducting power. Almost all surfaces can be rendered conductive, without blackleading, by means of the phosphorus PREPARATION. 1 7 7 and silver nitrate solution previously mentioned. The blacklead employed (p. 149) should be of the finest quality only, and care must generally be taken to secure a high polish. Some surfaces can be blackleaded dry, others should be breathed upon or held over the vapour of spirits of wine. In the case of silver conductive films, the depositing should always at first be rapid. Bronze powders of different kinds have fre- quently been recommended as suitable to the pro- duction of conducting surfaces. The finest gold bronze may thus be employed, mixed with the plumbago. Mr. Gore recommends white bronze powder of the best quality. All these metallic powders may be used with the most satisfactory results in art electro-typing, where the finer lines are of little consequence ; but they must not be em- ployed in electro-typing fine engravings, although often of use in copying set-up type. The plum- bago itself may be gilt, which greatly improves its conducting power: Dissolve i part gold chloride in 100 parts of sulphuric ether in an open vessel ; add 50 parts of finest plumbago, mix perfectly, and expose the compound to the sunlight, frequently stirring it until dry. It is applied in the usual way. In taking moulds of rough and large objects by pressure, a thin coating of fine white bronze powder may be dusted over the substance to form the mould ; the blackleading may afterwards be carried out with much greater ease. Printing surfaces, especially of type, should not N 178 ELECTRO-TYPING. be electrotyped upon moulds rendered conductive by the phosphorus and silver method, because the deposit is always brittle at the surface, and set-up type shells are generally very thin, espe- cially at the heads of letters and lines. Failures. These make their appearance in and after the depositing process ; but they are usually due to some part of the preparatory work being neglected. Failures are very rare when the mould has been properly made, and its surface carefully blackleaded, or otherwise rendered conductive. Holes through the shells are due either to non- conducting spots or to unequal distribution of the negative pole ; small pin-holes are usually caused by gas, due to too strong a current, or to air bubbles, which may be swept off. A total failure of deposit can always be traced to a failure of the current, either through the battery or at the con- tact points. Partial failure of deposit is usually due to careless facing with the conductive sub- stance, or to a very partial distribution of the cathode pole. These defects should be arranged for and foreseen in the preparatory process. Dirty deposits are usually due to dirt from the anodes. Electrotyped copper is generally clean, and should be used when this troublesome fault appears ; the defects may also be due to faults in the surfacing. The succeeding chapter is devoted to a description of the depositing process, which should be partly understood before even facing a mould is at- tempted. CHAPTER VIII. The Depositing Process. IN the preceding chapter and the present one the two most important operations in the electrotyper's art are dealt with. The depositing process, which is now to be described, is the most interesting in the whole art, because by its aid we obtain the actual electrotype, and reap the reward of all the patience and skill we may have devoted to the acquisition of fundamental knowledge and the mastery of manipulatory details. The preparation of representative types of the various kinds of work likely to pass into the hands of electrotypers has been fully described ; which means that we have obtained moulds upon which electrotypes are to be deposited, prepared objects themselves for direct negative electro-typing, and carefully provided each with a good conducting surface, and also with the necessary leading wires or single connections ; the work is, in short, ready to be hung in the solution to form the electro-type. In Chapter V. is described all the apparatus employed in the depositing process, and we must l8o ELECTRO-TYPING. refer back to that section if not fully acquainted with the construction of the depositing vessel and its furniture. The battery, or source of power, is spoken of at length in Chapter III., and to the concluding portion of that section reference should be made in case of doubt as to the way in which the action or connections are regulated to obtain more or less current or electro-motive force. In the present chapter will be given many details regarding the employment of electricity in deposit- ing, but they will be found to prove insufficient unless studied in conjunction with the portion of Chapter III. just referred to. The Various Processes of Deposition. Reference to Chapter I. will afford information as to the various methods adopted in depositing copper electrotypes, but, from a fundamental standpoint, they are all the same, with modifications in the arrangement of vessels and source of electricity. It will further be observed that throughout this work only one method or process is recommended for operations of practical importance. This pro- cess consists in the employment of an independent source of electricity and a simple open depositing vessel of a size suited to the magnitude of the operation, with leading wires and anode. Single-Cell Method. This process for producing small electrotypes has been partly described at p. 25, but a number of important points in the after-process remain to be dealt with in this place, THE DEPOSITING PROCESS. l8l The method from first to last is only well adapted to experimental work or to instruction combined with amusement ; but it is extensively practised on the Continent in the production of even large electrotypes. It is, however, too slow, and is not applicable in cases where the electricity required is derived from other sources than zinc and sulphuric acid. Assuming the matrix or cathode to be ready for immersion in the solution, it should be carefully noted whether the zinc-wire (negative pole) is clean where the work touches it, and that its connection with the zinc itself is without doubt metallic and clean ; any fault at those points, or at the con- junction of the conducting face and leading wire of the matrix, will either greatly retard the pro- gress of the work or entirely stop the current. It will be observed that this process may at any time be conducted in a common Daniell's cell by simply removing its copper cylinder. The single- cell process is merely the working through itself of a Daniell-cell current, because the matrix to be deposited upon serves the purpose of the copper cylinder or negative element. When the mould is hung in the solution, a deposit of copper is at once observed to form upon the wire. This preliminary deposition enables the operator to determine whether his current is of the required strength to produce malleable copper. If the deposit should appear very pale, and be slow in forming, it may be assumed that the current is 1 82 ELECTRO-TYPING. too weak. This is remedied by either placing the mould nearer to the porous cell, or placing an additional drop or two of sulphuric acid in the latter. If the deposit should appear of a very dark red or black, it indicates that the current is too strong ; this may be remedied by placing the mould farther away from the cell, or by lifting the zinc partly out of its exciting liquid. It is better to see the copper appear rather dark than the reverse. When a good colour is obtained, the de- position may be allowed to proceed ; the tempera- ture should not be under 60 F. The effects of temperature are very marked in the depositing process, a difference of a few degrees often giving rise to failure. If the temperature be higher than 60 F. the current will prove more vigorous, and the reverse with a lower temperature. The deposit will spread slowly, commencing upon the wire, over the upper portion of the mould, usually around the edges, and finally all over the face. When it becomes as thick as brown paper, or good writing paper, it may be removed from its matrix by gently heating it. The whole should be plunged in warm water in doing this ; but in any case the deposit should not be overheated or dragged off the mould forcibly. When the electrotype of a medal is intended to exhibit one face only, it should be strengthened by a backing of lead and tin, but pitch or shellac may be employed for small work. (See Final Preparation, Chapter X.) THE DEPOSITING PROCESS. 183 Holes in the electrotype are generally caused by defective facing with blacklead, or by removing the deposit before it has attained a sufficient thick- ness. It will be observed that the deposit is thickest upon the prominent points of the matrix and thinnest in the sunk parts, so that in removing it should first be insured that a sufficiently strong shell has been deposited throughout. In deposit- ing, the face of the mould should always be turned to the porous cell, or one face at a time if both be conductive. If the mould or object should be round, it must be slowly turned towards the cell as the deposition proceeds, because the thickest deposit is always made upon the nearest points of the cathode. Hence, if we take a copper plate and bind it to a V shape, slinging it in the solution so that the apex of the V may be nearest to the cell, we shall obtain a deposit beautifully graduating in thickness as the sides recede from the zinc. The deposit is thus thick at the apex and thins off upon the sides. The time occupied in depositing a copy of a medal or a small engraved block depends greatly upon the size of the cell and work. In a cell capable of containing two quarts, about 10 grains of copper per hour may be expected, because the current may prove less than a veber, which will give a deposit at the rate of 17 or 18 grains. Twenty-four hours may be taken as a general average ; but when the electrotype is required to be quite rigid, with no after backing, it may be 1 84 ELECTRO-TYPING. made of any thickness, say, up to -j-^th of an inch, which may require the action to be continued for a week. In any case it will be found that for small cells about 10 grains will be deposited per hour, and 20 grains in large cells. In the case of continuing the action for some time, the instruc- tions given at p. 50 for the management ot Daniell batteries fully apply to it. Nodules are small projections upon the electro- type when a thick shell is required ; they are troublesome, because they divert the force in their own direction and increase in size very rapidly. It is usually best to remove the electrotype and file them off, cleaning the surface again by a dip in nitric acid ; after which the deposition may pro- ceed. Sometimes these troublesome projections may be nipped off with a cutting pliers. When the electrotype is first detached from its mould it presents an extremely rich and beautiful appearance, which is speedily destroyed by ex- posure to the air. Should it be desired to retain it as much as possible, the surface may be warmed (heating above a certain point will destroy the colour), and pale lacquer applied with a camel-hair brush. Only a very thin coating should be brushed on. Or it is common to colour the surface by bronzing and other methods. Brown Finish. This is easily obtained by moist- ening the face of the electrotype with water to which a little nitric acid has been added, allow- ing it to dry, and then gradually heating it until THE DEPOSITING PROCESS. 185 the required shade is obtained. Many beautiful effects may be obtained by producing a dark brown, and then brightening some of the pro- minences by rubbing with a cloth or leather dipped in aqueous ammonia. The dark coating is oxide of copper. A more permanent effect may be produced by rubbing the electrotype face all over with rouge and finally covering with rouge and heating to near redness. Black Finish may be obtained by dipping re- peatedly in a weak solution of platinum chloride, or by polishing up with plumbago, or by holding over the smoke of burning straw. Other methods, especially applicable to busts and the larger electrotypes, will be found described in Chap. X. THE STANDARD PROCESS. It is assumed that the reader is already acquainted with the source of electricity to be used, as described in Chapter III. ; with the solution from which the electrotype is to be deposited, as spoken of in Chapter IV. ; with the depositing vessel described in Chapter V. ; and with the preparatory methods recommended in Chapter VII. Flat Work. The method by which flat electro- types may be deposited is not in some particulars adapted to hollow or round work. Flat work is the most easily managed. It includes all kinds of wood engravings, flat works of art, and formes of set-up type, with and without woodcuts. The most essential particulars relating to lead- ing and connecting wires are given in Chapter VII. ; 1 86 ELECTRO-TYPING. and in the case of woodcuts and formes of type, where moulding boxes are employed, no difficulty will ever be met with, because the connection with the blackleaded face is good throughout. But when metallic moulding boxes are not employed, and the mould is taken on a body of gutta-percha or other substance, the case is different, as the conduction, if simply arranged to begin at one point, will cause the deposit to be heaviest at that point, and will retard the spreading of the de- posit. It should be observed that all the leading connections are well distributed about the matrix, and that the battery connections are cleanly made with both anode and cathode rods. It is very im- portant also to observe the preliminary moistening mentioned at p. 167. To commence operations, the mould being ready and the solution in its vessel, the battery should be set in action. One cell of a Smee, bichromate, or Daniell battery, if large, will suffice for the main deposit ; but to drive the copper over the blackleaded face at first requires in some cases two cells, or a higher electro-motive force. In any case, two cells joined together for electro-motive force will hasten the first coating ; even three cells may be used if the work be over a foot square. In like manner the thermo-electric or dynamo-electric currents should be regulated to give much force at first. Lead a conductor from the positive pole of the electric source to the anode rod of the depositing THE DEPOSITING PROCESS. 187 vessel, and another from the negative pole to the cathode rod (it will be remembered that the cathode in our case is the surface receiving the electrotype). Select a plate of clean copper for the anode, with a surface equal to the cathode, and hang it in the solution from the anode rod. Hang, also, the cathode from its rod. The distance between the two cannot be stated without also knowing the strength of current and other particulars. They may at first be placed six inches apart, if large. The copper will first appear at the edges of the conducting frame, or upon the wire. Its colour and appearance will show whether the cathode is too near to the anode. If the deposit should exhibit a rather dark colour it may be left alone, as greater surface will remedy that and give it a lighter appearance ; but if it be in the shape of black grains the plates must be separated. When the deposit begins to form upon the mould itself, its progress will be but slow until it has quite covered the surface. Hard Brass-faced Electrotypes. When copper is deposited slowly upon a mould from a printing surface, it tends to be harder than when deposited quickly. But it does not usually answer the pur- pose to deposit slowly : too much time is consumed, and the metal is apt to be too brittle. The author, in the course of some experiments, fell upon a method by means of which the electro- type can be faced from the commencement with a very hard alloy of copper and zinc. This facing 1 88 ELECTRO-TYPING. presents all the advantages of a copper face, lasts twice as long, costs little extra, and, moreover, takes the coloured inks readily without apparent deterioration. The solution employed is simply a copper one, in a separate vessel, which has been worked with a rolled brass anode until an alloy deposit could be secured upon a blackleaded mould. The quickest way is to make up a brassing solution, as directed at p. 1 1 5, and to work this with a pale brass anode. What is required is a preliminary deposit of hard alloy upon the mould. The battery power should in all cases be greater than that used for copper alone. With moderate battery power the facing deposit will require more time than usual. The prepared mould is placed in the facing solution and a thin deposit thrown all over its face. It is then transferred quickly to the ordi- nary copper solution, and finished as usual. More than ordinary care should be taken to prevent gas from settling in the hollows of the mould in the facing solution. The battery power should be equal to two or three Bunsen cells. A pale deposit secured slowly with moderate battery power is harder than the same deposit precipitated quickly with great battery power ; therefore the facing deposit should be arranged to form slowly. If too pale the deposit will be soft, and if too red it will be soft. A medium can be struck between the two, when the maximum THE DEPOSITING PROCESS. 189 of hardness and the minimum proportion of zinc may be precipitated. In Chapter IX. this method is mentioned in connection with brass- facing, and some further remarks made upon its working. It is applicable to copies from steel plates and wood blocks, and may be used with advantage upon moulds taken from type. Brass, of whatever quality, is always much more difficult to deposit than copper ; and to those unacquainted with its nature some preliminary difficulties are presented in the working of this process. Precautions against Gas Bubbles. A wide camel- hair brush should be passed over the face of the mould two or three times while the deposit is forming, care being taken to reach the hollows, because gas is liable to accumulate in them and cause holes to appear in the electrotype. Temperature is of great importance in electro- deposition ; a fall of a few degrees will necessitate the employment of greater battery power ; 60 F. is the best working temperature. As soon as the copper has completely covered the surface of the mould, one of the cells, if two be used, may be disconnected and the work allowed to proceed with one cell, or both coupled for quantity. In most cases the plates may be ap- proached more closely together as soon as a com- plete deposit is secured. It should be a rule to work as near to the anode as possible, so far as good copper may be obtained; in fact there is little danger of bad metal being deposited afte.r 1 90 ELECTRO-TYPING. the mould is quite covered. The current may be augmented according to the speed required. A slight addition of caustic soda to the solution will quicken the rate of deposition. With the fullest current which may be applied, a good shell from a flat surface may be deposited in five hours. This is very rapid work. From eight to eighteen or twenty hours is the general time, according to the current employed and the skill of the depositor. A skilful electrotyper can work with dynamo-electric current at a very rapid rate. In America electrotypes of set-up type and blocks are frequently deposited in less than five hours ; indeed, they are often finished and in the printing-press within five hours of placing the mould in the depositing vessel. As a general rule the electro-motive force of one cell is made to both start and keep up the depo- sition, but time is saved by employing two or even three cells at first. This applies so far as the forcing of the deposit all over the mould is con- cerned. When it forms a complete covering, however thin, the tension should be reduced, because it is expensive and not necessary. After- wards, until the electrotype is complete, the cells may be joined up for quantity. A lo-gallon Daniell or Smee cell should deposit at the rate of (at least) about 51 grains per hour. This is the work of three vebers in a low resistance. Two cells should do double this work when coupled for quantity. THE DEPOSITING PROCESS. 191 During the deposition frequent motion of the cathode is advisable, especially when dealing with thick deposits, because vertical lines, usually pre- senting an appearance of a large note of exclama- tion (!), are found upon the back of the plate. When the mould is frequently shifted, or kept in motion in the solution, the metal is more regu- larly deposited. In the case of working with the dynamo-electric machine it is especially necessary, owing to the rapidity of the process, to keep the solution in motion. In some cases this is done by means of a screw, similar to a steamboat propeller, which is mounted upon a short shaft supported upon two plummer-blocks in the vat, at one end. The motion is given by a band which is driven from the shaft that rotates the dynamo-electric machine. In this way, as the propeller and band are at one extremity of the vat only, the operator is free to occupy with his work nearly the full length of the vat. The propeller- shaft may be hung horizontally or vertically. In any case the propeller should be about 8 inches above the bottom of the vat. The continued motion gives a regular rotation to the solution. In some cases the mould itself may be moved, but it is usually better to rotate the solution. Wire nets are frequently employed to separate the bottom sediment and prevent it from rising to the surface of the liquid and mould. Faults and Failures are always caused by defects in the solution or mould, or in the battery. One of I q 2 ELECTRO-TYPING. the most troublesome of faults is due to want oi care to free the mould from hydrogen gas when employing a strong current. These gas bubbles cause pin-holes. The pin-holes may also be caused by faulty blackleading. These holes cannot be discovered until the electrotype is removed from its matrix and held up to the light. When working with a strong current it is advantageous to dissolve a little chlorate of potash in hot water and stir it into the solution. This is believed (as it contains so much oxygen) to act as an absorber of the hydrogen ; but in any case the camel-hair brush should be passed lightly over the mould two or three times during the process of covering the mould. No mould while receiving a deposit should be removed from the trough for any considerable time or until it becomes dry. In the case of its being necessary to remove the mould, it should be kept under water until it can be replaced in the solution. Nor should the fingers be allowed to touch the mould or deposit, except under water ; the slightest trace of foreign matter will prevent adherence at that point. Thickness of Deposit. The usual thickness of shell is about -g^nd of an inch. It may be ascertained by removing from the solution and with a knife gently raising a corner (the thinnest corner) of the deposit. When satisfied that the shell is sufficiently rigid and complete it maybe removed from the solution. Separation of the Shell from the Matrix. When THE DEPOSITING PROCESS. 193 it is decided that the deposit has attained a suffi- cient thickness (minimum -j'^nd of an inch) wash well in cold water, and afterwards pour hot water on the back of the shell. This will have the effect of melting the wax composition and releasing the shell, which should now be carefully rinsed in both hot and cold water and held up to examine for pin- holes. When only a very few small holes are found they may be marked, and the plate laid aside to be completed, backed, and mounted. The deposit should be rejected if holes appear upon the lines of the engraving, or upon type, so as to render it difficult to repair them. Further information regarding the process, but generally applicable, is given further on. Electrotypes from Steel Engravings. r ihis is known as " fine work," and the matrix is prepared as directed at p. 1 68, finishing with the conducting solution. The deposit of copper is secured in exactly the same way as in the foregoing instances, but the electrotype required is much thicker, and frequently takes from one to two weeks to deposit. The thickness varies with the size, but a general gauge is -fa inch, or more than double the ordinary thickness. A light metallic frame should be used, by means of which the mould may be hung in the solution without risk of warping. The first deposit should be driven on quickly by the aid of high electro-motive force. The greatest care should be taken to turn out such electrotypes as perfectly as possible, because they are expected to exhibit all O 1 94 ELECTRO-TYPING. the excellent features of the original. All such electrotypes of steel-plates are afterwards ^steel- faced" a process which is described in Chapter IX. Finishing Details. These will be found applic- able to all classes of work in Chapter X. ; they consist in tinning, backing, squaring, planing, "picking" &c., and finally mounting on wood for printing. Coppering Iron Cylinders. The old method of coppering the iron rollers used in calico and paper printing was by means of a single cell and a number of porous pots arranged around the sur- face. The improved plan is much more rapid, and is incomparably cheaper. The dynamo-electric machine is usually employed to furnish the current required. Large vats of solution are used, and the anode plates are curved to correspond with the curvature of the cylinders. By these means from four to six pounds of copper can be deposited upon a cylinder in eight hours. The solution employed in. the preparatory process is a cyanide one, de- scribed at p. 103. In this solution, as described, the cylinder is merely covered with copper. The main deposit is secured in a common sulphate solution. The vats should always be horizontal ones, and the cylinders should be rotated slowly. DEPOSITION OF ART AND OTHER WORKS. This section is devoted to special treatment of art work, or electrotypes where rounded and undercut sur- faces are constantly met with, presenting greater difficulties than plain flat work, as treated above. THE DEPOSITING PROCESS. 195 One of the most important points to be constantly observed in depositing work with uneven sur- faces is the tendency of the deposit to become thickened upon points and edges. Thus, a rounded surface presented to a flat anode will not receive a regular deposit ; the shell of copper will be thickest at the line nearest the anode, and will from this point graduate off to nothing. This is another way of simply saying that all parts of the cathode face must be equi-distant from the anode face. The smaller the articles deposited upon the more true is this, because the effect of the current is not sufficiently diffused to include all irregu- larities of the surface. All rounded exterior surfaces can be deposited upon regularly by the use of one or a pair of concave anodes. The anode plates in this case should be thin, and may be bent and curved to answer pretty closely to the outline of the cathode. When both sides of an object are to be deposited upon at once, it is better to employ two curved anode plates, so arranged as to allow free cir- culation of the liquid by agitation or otherwise. In some cases the nature of the exterior surface may necessitate the employment of several anode plates, all connected, of course, to the positive pole of the battery. The main object is to effect an equal distribution of anode surface over the object. A fiat object to be coated upon bath sides at once may be hung between two anode plates, or between the two sides of one plate bent to a y shape. 196 ELECTRO-TYPING. Outside Under cuttings. When a surface is very irregular, and especially when it is undercut to any considerable extent, it presents points diffi- cult to commence a deposit upon. In many in- stances these undercuttings are so deep as to prevent the effect of the anode from reaching them. In most cases, also, these are met with upon blackleaded work, which augments the difficulty. But by a little skill the deposit may be commenced at those very difficult points by at first keeping out the regular anode, and employing one composed of a twist or two of copper wire, or a small plate sufficiently large to enter the deepest cavities of the cathode. When only a few of these cavities appear, the miniature anode may be mounted upon the end of a stiff wire, so that it may be bent to the position re- quired to lead the deposit just where the operator requires it to fall. In some cases the current will be found too strong, and apt to give a black de- posit if the regular anode is removed ; but in any case the larger anode should be kept back until the hollows have been deposited in. By select- ing a stiff, stout copper wire, and making as many loops upon it as will answer to the chief hollows, it may be so bent and arranged in a few minutes as to lead the deposit regularly into the hollows. These supplementary anodes must in all cases be connected with the positive pole of the battery. Or another plan may be adopted from the be- ginning; but it is not generally applicable or neces- THE DEPOSITING PROCESS. 197 sary except when the undercutting is beyond the reach of the blacklead brush. Each hollow may be made to conduct better than the general surface by means of precipitated nitrate of silver (p. 169), or other solution used with elastic moulds. Under- cut surfaces are, however, frequently deposited upon without any of the devices here mentioned. It is well known that a high electro-motive force tends to spread a deposit over a refractory surface. In this way it is by no means impossible to drive a deposit over clean gutta-percha. Hence, by add- ing to the electro-motive force of the battery, and employing only a small anode, most of the ordinary depressions on a mould may be reached very shortly after the general surface has been coated. It is, however, of the greatest importance to secure strong metal upon hollows, because these require the most strength, being the prominent portions of the electrotype. The solution in the hollows, if allowed to rest, is very apt to become weak. The same may take place when anodes are employed to surround a cathode : in all such cases the solution must be made to circulate, by gently stirring or by shifting the anodes and cathode frequently. In some cases also copper anodes, unless of electrotyped copper, are so impure that the dirt set free effects much mischief. Platinum foil and wire are ex- tensively employed as anodes, where common copper would be inadmissible. Instances of these applications are given further on in this chapter. 198 ELECTRO-TYPING. Interior Work. Deposits upon the interior sur- faces of moulds present those difficulties which most try the skill and forethought of the electro- typer. They must be iormed, as has been shown in the section devoted to Preparation, upon all kinds of surfaces, and upon all the usual moulding materials. The most important outlook is to secure a really good conducting surface, as strong in the hollows as upon the heights. The nega- tive conducting system must be as perfect as pos- sible, and should especially include branches to all the hollow parts, as recommended at p. 175. These systems should, as much as possible, be so arranged as to allow of an anode being hung in the mould. The shape of this anode, in the case of a bust, should to a certain degree correspond with the interior outline of the mould. Anodes of platinum wire are frequently employed in this way, made up as a kind of frame to the general interior outline, but small enough to avoid risk of touching within the mould. These anodes are afterwards, if the deposit be of the shape to necessitate it, pulled out through a hole ifi the head of the bust, or from underneath. In most cases of bust work, however, including many natural objects, there is an opening at the base of the mould large enough to allow of the use of a cylinder of sheet copper as an anode. A constant stream of the solution should be caused to flow through all interior moulds where copper anodes are employed ; this is necessary, because these THE DEPOSITING PROCESS. 199 anodes are constantly giving off dirt, which is apt to fall into hollow places and so prevent the for- mation of a strong deposit there. A stream of the solution issuing from the lower part of the mould will carry all the usual impurities with it to the bottom of the vat. Air bubbles, which in all classes of work give great trouble to electrotypers, must be especially guarded against in the deposition of interior work. Gas must also be avoided by regulating the cur- rent. Dipping the mould, or wetting it within, with spirits of wine has been recommended, but it is probably best to carefully carry out the instruc- tions given at p. 157, regarding thoroughly wetting every portion of the mould with water simply, before placing it in the solution. A camel-hair brush may also be employed when the hand can be placed in the mould. Some of the largest electrotypes, as that of the Earl of Eglinton (13^ feet high), made by Messrs. Elkington, are deposited by the process mentioned at p. 173. By these means, although the original (plaster bust or model) is destroyed in the process, most of the difficulties are removed, and a convex anode, with a skilful distribution of leading wires, secures the formation of a rigid shell. By these means the shell is deposited in parts and after- wards soldered together. The great advantage of this method lies in the certainty with which the deposit may be led over the whole surface. Each section should be deposited to a given thickness, 200 ELECTRO-TYPING. or the lower portions of a statue may be made thickest to give strength to the whole. The deposition of copper as applicable to every kind of art work may be fully studied upon exte- rior rounded surfaces. As much as possible the primary conditions should resemble those applied in common flat work ; that is, the copper must be led to the required points by an intelligently- arranged system of anode surface and negative leading wires. The anode and negative wires should act in conjunction in drawing the deposit into difficult hollows. The deposit always first falls at the point where resistance to the current is "weakest. Following this rule the protruding portions of the mould need no special arrangements to draw the deposit towards them. In Chapter VII. are given numerous particulars in the preparation of the work previous to placing it in the depositing vat. We are chiefly concerned here with the actual deposition of the copper, which is always comparatively easy to carry out when the work has been carefully prepared. The three chief points to observe are to obtain good copper, to obtain it in the hollow's first, or as soon as pos- sible by a combination of negative conductors and anodes, and to prevent the deposition of dirt upon any portion of the mould. The Cause of Slow Deposits. Slow deposits are always caused by weak currents ; but the weak- ness of the current may arise from a variety of causes. As a rule, the deposit upon a blackleaded THE DEPOSITING PROCESS. 2O1 surface is slow in forming, but this is due to the great resistance offered by the imperfect conductor. As soon as the surface is covered the speed of deposition is greatly increased if the current be of proper strength. Then it follows that if a good strength of current be passing a corresponding amount of copper should be secured. It will, of course, be understood that as long as the actual facing is being deposited the work will be slow unless the electro-motive force be increased. There is no economy in increasing the current during this stage of the process. When the word current is used here it signifies the actual current, not the current which might pass if the resistance and dis- tance apart were reduced. Thus, the currents yielded by a battery when on short circuit and when depositing copper are very different in strength. Work of any kind always reduces the current, and it is the amount of electrical energy actually passing that we have to deal with. Hence the work or depositing rate may be taken to be proportionate to the actual current. A rise of temperature will increase the current by decreas- ing the resistance. Dirty Anodes, It may prove both interesting and instructive to give some particulars of the cause of the films observed on copper anodes. They are usually brown or black in colour, and appear on the dissolving surface in proportion to the amount of copper withdrawn. This dirt is a source of great trouble to the operator, because it 202 ELECTRO-TYPING. not only necessitates frequent cleaning of the anode, but falls to the bottom of the vat, and when disturbed is apt to get upon or into the moulds. If the plan recommended by the author that of using only Daniell cells and employing their electrotype copper for anodes were once tried, it would probably be always used, because the copper is quite free from the foreign matters spoken of as dirt. A chemist on analyzing the dirt found it to con- sist of a great number of different substances, among which the percentage of tin was 33, of copper 9, antimony 9, arsenic 7, silver 4, sulphur 2, and nickel 2. Cause of Nodules. These are little lumps of copper which frequently appear on the back of an electrotype and retard the progress of the real deposit. They are caused chiefly by employing a current too small and an electro-motive force too high. The formation of these warty excrescences, however, greatly assists in the spreading of a deposit over a refractory substance ; they exert a repulsive effect which undoubtedly assists to a con- siderable extent the driving of a deposit into hollows in the mould. In such cases the current must be small. (See p. 197.) Redissolution of the Deposit. This must be espe- cially guarded against, as, besides retarding the progress of the work, it is apt to render it porous and spongy. It is chiefly caused by carelessly allowing the battery pov/er to become too weak, THE DEPOSITING PROCESS. 203 when the counter force of the depositing-cell (p. 1 8) is allowed to come into action to reverse the direc- tion of electrolysis and dissolve the cathode. The same may take place when the dynamo-electric machine is employed, by allowing the work to remain in the bath while the machine is idle. In this case, if an efficient safety circuit-break, such as that devised by the author (p. 84), is not fitted to the circuit, the polarity of the machine is very apt to become reversed, and the current reversed also on again starting the machine. The result is, of course, to dissolve the deposit, and probably destroy the mould. (See also p. 83.) Dynamo-electric Working. Most of the necessary directions for the management of dynamo-electric machines have already been given (p. 82, Chap. III.}. The bulk of liquid should be large, and an extended system of anode and cathode rods should cross the vat. The deposits are obtained with full current much more quickly than by the battery current, but no rapid deposition can be done on very small work ; this is the reason why dynamo-electric cur- rents are not economical unless employed in large baths upon large electrotypes. The battery current is better adapted in many ways for work of mode- rate size, and although it cannot be quicker in action than the machine current, it is in small operations much cheaper and more easily handled by the operator. Cost of the Process. Machine work is very much cheaper than battery work, and the copper on 204 ELECTRO-TYPING. large electrotypes deposited by machine is usually of better quality. The actual cost of the dynamo- electric current per pound of copper, including labour, is frequently less than threepence, but the general cost with small machines will be higher. The battery current, reckoning the zinc salts, &c., to be thrown away, cannot be much less, without labour, than sixpence per pound of copper, because the zinc costs about fourpence per pound and acid about three halfpence. As a rule, the battery is more expensive than this, even in skilful hands, because two pounds of zinc are frequently dissolved in depositing one of copper. The process of depositing hard facings for elec- trotypes is described in the succeeding chapter. CHAPTER IX. Hard Facings for Electrotypes. ELECTRO-deposits of iron are exceedingly hard and strongly adherent. When a copy from an engraved steel plate is thinly coated or faced with iron by means of electricity it is said to be " steel- faced," and the term does not appear to be inap- propriate when it is stated that a steel-faced elec- trotype can be made to stand wear even better than the original steel engraving. Iron electro- deposition is, indeed, almost confined to the facing of electro-plates. When the steel face wears off the residue may be dissolved away by means of dilute sulphuric acid without injury to the real face, and the process repeated with all the original sharpness an indefinite number of times. The iron takes ink more readily than most surfaces, and cannot, like copper, be injured by printing in ver- milion, the mercury of which combines with copper. The plates from which bank-notes and cheques are printed are in most cases iron-faced. Nickel may be used for the same purpose, and has lately been tried by the author with success. It is hard, strongly adhesive, and is more easily 206 ELECTRO-TYPING. deposited than iron ; it possesses, indeed, all the good qualities of iron without its tendency to rust. The iron depositing solution is readily decomposed by absorbing oxygen from the air, and otherwise gives much trouble. Nickel solution, on the other hand, can be kept for years without spontaneous decomposition occurring. On account of these obvious advantages, directions for working a nickel solution are given at p. 114, and instructions for its use further on. Preparation of the Copper-plate. At p. 1 1 o will be found directions for making up an iron solution, and for its preservation when made. When a copper copy of a steel engraving has been secured, as directed at p. 103, it is removed from the solution and well washed : a level wooden block of the same size as the plate is covered with an adherent layer of stearine or wax, and the warmed copper-plate pressed face downwards upon it. When well secured in this way, and the face is protected from possible injury, the edges are sawn off square with the circular saw ; the back, covered as it is with variously-shaped excrescences of copper, must be partly filed, and afterwards, if possible, planed level ; the plate must, in fact, be made of a uniform thickness throughout. It is afterwards removed and the edges bevelled, so that when finished the plate shall be similar to the original. Before steel-facing, the surface of the plate is cleaned off carefully by means of turpentine, ben- zine, and finally hot caustic potash solution, when, STEEL-FACING. 207 after washing, it is ready for the depositing process. Care should be taken not to touch the face of the plate with the fingers, as at that point the deposit of iron is liable to be defective and strip in the printing. The plate may be suspended in the solu- tion by means of two hooks of copper wire, upon which its lower edge may rest ; or a copper wire may be soldered to the back. The former method is generally considered the better. A battery current of one gallon Bunsen cell (p. 50) is frequently employed, but it is too weak. Two cells should be used, exposing in each a sur- face of zinc at least as large as the plate to be faced. It is usually convenient to first immerse a plate of copper to find at what distance the anode should be placed from the cathode. The anode should have a surface about five times larger than the plate to be coated. When immersed for a few minutes, and a whitish coating is observed to spread over the surface, re move, wash, and rub with a brush ; remove again and wash after a few minutes. Treat as before, and when the iron has spread well into all the lines it may be considered sufficiently deep. Wash the plate in hot water very carefully when finally removed, and if not intended for immediate use, dry slowly and coat the surface with bees'-wax by the aid of heat. The deposit must not, of course, be allowed to go so far as to affect to any considerable extent the fine lines of the engraving, but it must be allowed to cover the whole surface of the plate. When a 208 ELECTRO-TYPING. strong current is used the deposit is more apt to contain gas, but this can be avoided by more fre- quent removal and brushing. The fingers should not be allowed to touch the face of the plate, except under the solution. A very large anode must also be used, otherwise the solution will get weak and acid. In this pro- cess the usual practice of providing an anode of a size equal to the cathode must be departed from. The iron composing the anode should be as fine as possible. Charcoal iron is generally employed with the best results. Gas is very apt to come off in the operation, but its presence, as the deposit is so thin, may be overlooked. The plate may with advantage be gently swung from side to side during the process. Nickel-Facing. This process is much more easily carried out than that of iron-facing. The nickel solution required is described at p. 114. It should be in good order, neither distinctly acid nor alka- line, but if anything the alkaline tendency should predominate. It is not even necessary in deposit- ing small quantities of nickel, such as those required in facing plates, to employ a nickel anode, but it is always desirable and wise to do so. Occa- sionally a platinum foil anode can be made to answer, but the state of the solution must there- after be brought into working condition by the addition of the abstracted nickel, and also sulphate of ammonia to represent the alkaline constituent necessary to balance the acid. NICKEL-FACING. 2OQ A current irom one Bunsen cell will usually prove sufficient. Great care should be taken to remove every trace of wax from the plate to be faced by means of benzine, and afterwards to wash well in hot caustic potash solution ; it is even advisable to boil the plate in the solution for fifteen minutes, and afterwards to wash well in water. The fingers should on no account be allowed to touch the face of the plate, otherwise the deposit may fail to adhere to the parts. The anode should have a surface a little larger than the plate. When the latter is suspended in the solution, it will prove advantageous to go over its surface with a long- handled soft brush, to dispel any films of air or bubbles of gas. When the first trace of a deposit appears, the brushing may be repeated, and in a few minutes the plate may be removed, washed, and then replaced. At this stage the process is the same as that given for iron-faced plates. The deposit will be sufficiently thick when it has entirely covered the plate. A strong current offers no advantages; it is liable to produce a porous deposit, even in the extremely thin coating required ; it is apt also to fill the hollows with gas and prevent the deposit from spreading easily between the lines. The object to be attained is a deposit accompanied with little or no gas. Rapid deposits are apt to be softer than slow deposits in the copper solution, and this is not less true when applied to nickel. Deposits formed slowly are always more highly P 2 1 ELECTRO-TYPING. crystalline than those formed quickly, and are therefore harder and more brittle. There is little or no tendency to strip, even when the plate has been prepared carelessly. Brass-Facing. Electro-deposited brass may be made very hard, and thus forms a good facing especially for bookbinders' tools. The process is somewhat difficult, but there is the advantage of being able at will to obtain hard and sofc brass according to the proportion of zinc contained in the deposit. The solution required has been described at p. 115. The articles are prepared as for iron or nickel facing. The anode used should be of a hard yellow brass. One cell of the Bunsen type will deposit the alloy, but two are generally used to hasten the operation. If the brass should be red it will prove soft, and contain too great a percentage of copper. A solution with this defect may be corrected by the use of a zinc anode until the brass exhibits a rather pale colour. When the zinc constituent of the alloy is in excess it adds, up to a certain point, to the hardness of the deposit. The process of depo- siting should not be hastened, because too great a proportion of copper is then thrown down, and the zinc itself tends to add to the softness. What is really required in a brass-facing is great hardness and perfect adhesion between the real surface and the artificial face. The author has successfully tried a method of giving to ordinary electrotypes a very hard face by BRASS-FACING. 211 means of zinc. The first deposit thrown upon the mould, forming the surface of the electrotype, is precipitated by the aid of increased battery power, and in a solution of which zinc forms a part. This deposit secured, the electrotype is removed and completed in the ordinary copper bath. The result is a facing much harder and more durable than copper itself, with the additional advantage that it does not, like pure copper, readily give way when printing vermilion. A solution suitable for this work may be made in a separate vessel by simply working a copper bath with a brass anode and a current from about three Bunsen cells in series, until a good hard deposit can be secured upon a copper plate or a blackleaded surface. The ordinary copper bath should not be employed for the purpose. Gas is generally given off, especially at the cathode, the surface of which should be frequently cleaned by means of a soft brush. When the deposit becomes too pale employ a copper anode for a time. (See p. 187.) CHAPTER X. Final Preparation of the Work. AFTER an electrotype is removed from the de- positing solution, it is "finished;" that is, trimmed, backed, and mounted, if it belong to the printing class, or trimmed and joined to its corresponding section if it belong to the art electrotype order. The finishing of printing electrotypes is by far of the greater importance, and requires the exercise of the best skill ; it generally is, and always should be, a distinct operation, performed by special workmen trained to it. In most cases the finishing and correcting of printing electrotypes demands the attention of more than one special workman, as will be judged from the condensed description of the whole process given herewith. Finishing of Printing Surfaces. When the elec- trotype is judged to be thick and rigid enough (^nd of an inch for backed work), the mould is removed and well washed. It is laid electrotype upwards and hot water poured upon the latter; this has the effect of softening the wax and freeing the shell. When any fragments of the shell hang FINISHING. 213 over the edges of the mould they should be clipped off previous to heating. A minute examination should be made at this stage of the face of the shell in order to find any defects that may exist, especially pinholes. Tinning. The backing process is preceded by that of tinning, in which floating or tinning-pans and the backing metal bath mentioned at p. 137 are employed. The tinning-tray is first floated upon the molten metal until quite hot ; the electro- type is laid upon it, face downwards, and a quan- tity of hydrochloric acid, in which zinc has been dissolved to saturation, thoroughly brushed over its back. This solution of zinc is usually called tinning or soldering fluid, and should be kept in a bottle for use. The tinning metal is usually a mixture of lead and tin, prepared by melting together equal parts of tin and lead, and either running it into thin sheets, to be cut into strips for use, or pouring it into water to obtain grain solder. A quantity of this solder is sprinkled over the back of the shell, and caused to spread, when melted, by the aid of a stick of solder or a stiff brush wetted with the soldering fluid. The tin must in all cases spread all over the electrotype back, and must also be caused to " take " to the surface, as mercury is observed to amalgamate with zinc. Precautions. In the case of there being pinholes through the electrotype, the soldering fluid must be used more sparingly, because it is apt to find its 2 1 4 ELECTRO-TYPIXG. way through the defects and attract the solder to the front, spoiling the printing surface. If the soldering fluid should exhibit any tendency to turn black upon the surface of the shell, a little water may be added to it, also a fragment of an alkali, as chloride of ammonium. Care should be taken to keep the heat as low as possible, consistent with free diffusion of the solder. If the shell should exhibit a tendency to curl up at the edges, weights of any kind may be employed to keep them flat until backed and cool. Backing. When properly tinned, iron bars may be so placed, if necessary, as to confine the metal to be poured on to the surface of the shell. The backing metal is ladled out of the melting-pot and poured upon the shell, commencing at one corner, until a moderate thickness is attained, so that enough may be left to plane down to gauge. Both tray and shell are removed together and allowed to cool. Squaring. The superfluous width of shell and back may now be reduced by means of the circular saw to within one- fourth inch of the engraving or type, care being taken to cut square and straight to gauge. Levelling. Shells are seldom sufficiently rigid to prevent slight twisting or depression of the printing surface from appearing. When backed and cool they are, therefore, examined by means of a straight-edge and callipers, and any depres- sions from the general surface carefully marked on FINISHING. 215 the back. After this examination, the printing surface is placed upon a level and smooth iron block and the depressions corrected from the back by means of a smooth and round-faced ham- mer ; the blows should not be harder than will actually serve the purpose. When the face is " home " to the level, which is indicated by the solidity of the sound, it should be again examined from the other surface by means of the straight- edge. Sometimes the plate is further " planed " by the application of a printer's planing-block, of small size. Roughing. This is the next operation ; it con- sists in cutting away, by means of a "roughing lathe," all backing metal not parallel with the printing surface of the electrotype. In many cases this process is made to complete the plate previous to mounting. The lathe has already been described (p. 138). A single layer of thin paper should be smoothly glued over the surface of the revolving face-plate to prevent injury to the printing surface. The electrotype should be se- cured by means of the chuck-jaws as nearly as possible in the centre of the face-plate, and re- volved at a high speed. The cutting-tool or knife should be kept moistened with water. When the plate has been faced it is removed, and should be finished in the planer to the standard gauge. In both the roughing and planing operations care must be taken that the electrotype shall lie quite flat to the face-plate and the plan ing-bed. 2 1 6 ELECTRO-TYPING. In the former case the chuck-jaws must be set so as to obviate twisting or bending the plate, or otherwise disturbing its accurate flat surface. It is always well to have at hand a small printing- press, in which a preliminary " pull " can be ob- tained, to prove the flatness of the plate. Bevelling. It is now usual to bevel off the edges of the electrotype in the bevelling machine, men- tioned at p. 139 ; but in some cases it is done by hand with a sharp file. A bevelling-plane is, however, much better adapted to the work, but care must be taken in either case to avoid work- ing too near to the edge of the engraving or type. When the electrotype is to be mounted upon wood, the bevelling may be done by hand and file, but otherwise it is not only necessary to square and bevel off very accurately, but to make every plate of the same work correspond in size with any other plate of the set, otherwise much con- tusion is likely to result in arranging them for the printing process. Correcting and Routing. In cases where the original plate has been perfect and care taken in producing the electrotype, there should be little need for the troublesome process variously known as correcting, picking, &c. But in general prac- tice there is constant work for the corrector, in picking out accidental points of backing metal, clearing lines, repairing damaged letters, and so on. In addition to this each electrotype should be " chipped " or " routed " an operation which FINISHING. 2 1 7 means the deepening of the central portions known as the " whites," so that they may not black in printing. The picking process must be conducted with a steady and skilful hand by the aid of a few engravers' tools. In repairing battered letters it is usual to either "knock up" or otherwise raise the surface from the back, and so obtain matter to work upon at the face, or to drill out the letter, square the hole, and insert a new one by the aid of solder and the blowpipe. When new letters are inserted, or new portions of a woodcut, care must be taken to insure that the new portion shall not be higher or lower than the old face. This class of work is secured from behind by wetting it with soldering fluid and soldering by the aid of a blow- pipe and a few grains of tinning composition. All points of tin or backing metal projecting through the face, owing to holes in the electrotype, must be carefully removed with suitable tools. The chipping or routing operation is done on a small scale by means of sharp chisels with rounded faces and a hammer, but in the larger establish- ments a machine with a rapidly-revolving cutter is provided, which speedily cuts away and deepens the "whites." It is usually necessary in this ope- ration to cut away portions of the shell and somo thin portion of the backing metal. Additions to the Electrotype. In some cases the necessity arises for an addition to the plate, upon which the design of the engraving may be 2 1 8 ELECTRO-TYPING. continued ; or sometimes two electrotypes oi engravings may be combined to act as one. The greatest care is necessary in this work to insure that the joined edges shall be straight and true, otherwise the join will exhibit as a white line in the printing. The blowpipe and soldering bolt are generally employed in this work. Mounting. Electrotypes of woodcuts are usually mounted upon mahogany blocks (p. 139), which are afterwards accurately planed to type gauge. The block should be of the same size as the plate ; it should not in any case be smaller ; its surface must be perfectly level, otherwise the plate will be twisted, and will not print all over its surface. In most cases holes should be drilled in the plate for the pins, because driving them through the metal frequently tends to twist the surrounding portions. French pins with small heads are usually employed. They should be placed around the edges first; a pin or two should be driven well home in the whites. The holes should be counter- sunk, so that the pinheads may not protrude. A steel punch and hammer must be used. All the pins should not be driven home at once as they are entered, but afterwards, as the plate tends to lie on the block. Flatness and freedom from warping is the object of this. The electrotypes, after being mounted, are always gauged by passing them under a standard gauge mounted on a level plate. Each block should be planed carefully to the gauge, FINISHING. 219 or if anything rather thinner, as they can after- wards be corrected for height by underlaying with paper. Storing Electrotypes. Plates mounted upon wood should always be kept in a dry place, because the mahogany is apt to absorb moisture and warp or swell. As a rule, electrotypes of this class should be stored in shallow drawers, only slightly deeper than type-high. In packing, the printing faces must always be protected by one or two layers of soft paper, and care should be taken to so arrange the blocks as to be free from shaking or possible movement. The top and bottom faces of the sets of plates should always be turned towards each other for the sake of protection. Rotary Electrotyped Plates. The flat electrotypes may be arranged in the form of cylinders when required to be worked upon rotating printing machines. Several methods are in use. The shell should first be corrected to the flat form and then tinned on the back. In curving it a cylinder of the required size may be used, and an outer convex casing provided, between which and the electrotype back a layer of backing metal may be poured. The final corrections and planing may then be proceeded with, similar to the methods adopted in finishing common stereotype plates. By employing moulding cases of a convex pattern, filled to a uniform height with the wax composi- tion, convex printing surfaces may be deposited upon moulds from curved stereo-plates. 220 ELECTRO-TYPING. FINISHING ART WORK. Medallions may be backed with pitch, plaster of Paris, sealing-wax, or backing metal. In the latter case, the shell is placed on a wire-gauze plate, or on a bed of asbestos, and heat applied gently from underneath ; the back is wetted with soldering fluid and tinned exactly as described (p. 213) for printing shells. The backing metal may be poured on or melted in position by means of a blowpipe. This backing is, of course, applicable to all flat art work of the medallion kind. When two electrotypes of a medallion have to be joined together to resemble the original, they must be trimmed with the file and shears, and levelled to the required thickness. Heat may then be applied and the backs tinned ; a layer of back- ing metal may also, if required, be melted upon each. When the two sides are properly adjusted to each other, so that the faces may lie correctly, additional heat, gently applied to avoid oxidation, will melt them in position, and the edges may be finished off with the file. In some cases a slight coating of copper around the edge may be applied to cover over the join and give the reproduction a finished appearance. A number of recipes for colouring and bronzing the finished electrotypes of all kinds have been given at p. 1 84. Busts. When a bust has been electrotyped in two parts the shells are trimmed with shears and file until their separating edges agree. The^ edges may then be wetted with soldering fluid and tinned FINISHING. 221 with an ordinary tinman's bolt. When the edges are placed together, the flame of a lamp directed upon the seam by a common blowpipe can be made to heat the shells sufficiently to melt the tinning and secure the joint. When finally rubbed over with the file the joint may be bronzed. In cases where the hand may be placed within the joined-up shells the uniting process is sim- plified by employing the soldering-iron. In many cases the shells are too weak to stand fair usage, and they must be backed by tinning and pouring on metal, as described for printing plates (p. 214). The backing in this case should be allowed to run into the hollows, because these are usually the thinnest portions of the shell. These hollows are often so weak by reason of defective anode arrangements that a slight touch will dimple them, and they are frequently pierced with holes, due to air bubbles or gas. Through these holes the tin- ning and backing metal are apt to run, but the protuberance can easily be chipped off and the spots bronzed or covered with bronze powder dusted upon gold size. Shells that are required to support any consider- able weight must be more rigid than common shells. The additional strength may be always applied by means of backing metal. When large shells are heated to be tinned and backed, various substances may be spread over their surfaces, so that they may be floated direct upon the molten 222 ELECTRO-TYPING. backing metal. They may be blackleaded all over or covered with other substances to prevent the sur- face from " taking " the metal upon the wrong side. Smaller shells can be readily heated by means of a well-distributed gas flame through a bed of INDEX, ACTION, local, 63 Addition to electrotypes, Alkaline copper solution, 103 solutions, vessels for, 129 Amalgamation of zinc, 57 Anderson's salts, 53 Anode, 15 plates, 130 size of, 131 shape of, 132 dirty, 201 Apparatus, single cell, 25 Art, introduction to the, I nomenclature of the, 6 work, preparation of, 1 70 deposition of, 194 TRACKING metal, 37 bath, 137 process, 214 Battery, 10 plates, size of, 43 copper-plates for, 58 containing vessels for, 59 solutions for, 61 electromotive force of, 63 to join up, 67 care of, 68 work, cost of, 69 thermo-electric, 71 Noe's, 74 Bevelling apparatus, 139 Bevelling, 216 Blackleading brushes, 135 machine, 136 Black finish, 185 Brass, 37 facing solution, 115 faced electrotypes, 187 facing, process of, 210 Brown finish, 184 Brush, blackleading, 135 Bunsen cell, 50 Busts, finishing, 220 /"* ALICO -printing cylinder vat, 127 Carbon plate, 41 and zinc cells, 52 Care of battery, 68 Cathode, 17 Cells, Smee, 44 double fluid, 48 Daniell, 48 Grove, 52 carbon and zinc, 53 porous, 59 Chases, 133 Circuit, electric, J Circular saw, 138 Clamond's thermo-electric bat* tery, 72 Compound vessel process, 29 Condensed outline of the art, 4 Conductors and insulators, 8 from batteries, 54 224 INDEX. Conducting fittings for vats, i 25 wires and bands, 129 Containing vessels for batteries, 59 Copper, 31 electrolytic relations of, 33 immersion, deposition of, 34 quality of deposited, 35 plates for batteries, 58 solution for single eel: pro- cess, IO2 alkaline, 103 Correcting, 216 Cost of battery working, 69 deposition, 203 Current of electricity, 9 minor effects of the, 18 to increase, 67 measurement of, 89 detector, 90 T)ANIELL cell, 48 Decomposition _pf different solutions, 20 Deposit, simple immersion, 24 thickness of, 192 redissolution ot, 202 Depositing and moulding appara- tus, 118 vat, small, 118 for large operations, 122 trays, medallion, 154 process, the, 179 Deposition of art work, 194 cost of, 203 Detector of current, 90 Differential galvanometer, 95 Double fluid cells, 48 Dynamo- electric machine, 75 fixing of, 77 motor for, 80 care of, 81 current, regulation of, 82 machine, resistance coils for, 83 working, 203 "PLASTIC composition, 146 Effects of large and small electrodes, 22 Electric circuit, the, 7 Electricity, current of, 9 Electro-motive force, 9 Electrodes, 14 TiicJrdytes, 15 Electrolytic relations of copper, 33 Electrolysis of copper salts, 33 iron solution, 36 Electro-motive force of batteries, 63 pAILURES, 178 Final preparation of work, 212 Finishing art work, 220 busts, 220 Flat printing surfaces, preparation of, 161 Flat-work, deposition of, 185 Force, electro-motive, 9 Fusible alloy, 144 battery, 39 Galvanometer, 30 construction of, 92 tangent, 93 ordinary, 95 differential, 95 Galvanometer, Sprague's, 96 Gas bubbles, 189 Glue, marine, 148 Gramme's machine, 88 Grove's cell, 52 "LTARD facings, 205 Hints on preparation, 1 76 Hooks and "slings," 137 TMMERSION, deposition of copper, 34 Insulators and conductors, 8 Interior work, 198 INDEX. 225 Introduction to the art, I Iron, 35 salts of, 36 solution, electrolysis of, 36 facing solution, 1 10 solution, management of, 1 12 vessels for, 130 cylinders, coppering of, 194 facing, 205 T ATHE, roughing, 138 Leading wire systems, 175 Levelling, 214 Local action, 63 A/j ACHINE, dynamo-electric, Machine, Gramme's, 88 Weston's, 88 Wilde's, 88 Schuckert's,' 88 Siemens', 88 Maxim's, 88 Management of solution, 105 iron solutions, 112 Marine glue, 148 Maxim's machine, 88 Measurement of currents, 89 resistance, 96 Medallion depositing trays, 154 Metal, backing, 37 Methods of making solutions, 27 Minor effects of the current on electrolyte, 18 Motor for dynamo-electric ma- chines, 80 Moulding apparatus, 118 composition vessel, 134 materials, 141 Mounting electrotypes, 139 process of, 218 TSJICKEL, 37 solution of, 114 facing, 208 Nodules, 184 cause of, 202 Noe's thermo-electric battery, Nomenclature of ihe art, 6 f~\HM, the, unit of resistance, 90 Outline of the art, 4 pLANER, 139 Plaster of Paris, 145 Platinised silver plates, 43 Plumbago, 149 Polarity, reversal of, 83 Polarization, 19 Porous cells, 59 Precautions, 213 Preparation of the work, 152 medallions, 153 flat surfaces, 161 steel engravings, 167 art work, 1 70 hints on, 176 Pressure apparatus, 134 Process, separate current, 28 compound vessel, 29 /DUALITY of deposited cop. ^ per, 35 solutions, 109 n EGULATION of dynamo. electric currents, 82 Relation of current to work, 2 1 Resistance of the solution, 23 coils and shunts, 83 measurement of, 96 scales, 128 Reversal of polarity, 83 current in solution, I IO Rotary plates, 219 Roughing lathe, 138 operation 01. ?rc Routing, operatiau of, 2l6 226 INDEX. CALTS of copper, 31 electrolysis of, 33 Salts of iron, 36 Saw, circular, 138 Schuckert's machine, 88 Separate current process, 28 solution for, 102 Siemens' machine, 88 Silver plates, platinised, 43 Simple immersion deposit, 24 Simplest type of cell, 40 Single cell depositing apparatus, 25 process, 35 180 Size of battery plates, 43 Slow deposition, cause of, 200 Smee battery, 44 Solder, 38 Solutions, different, decomposi- tion of, 20 resistance of the, 23 methods of making the, 27 for batteries, 61 instructions for making, 99 copper, 102 management of, 105 new, test for, 109 quality of, 109 steel-facing, no nickel, 114 brass, 115 Sprague's galvanometer, 96 Squaring, 214 Standard process, the, 185 Stearine, 145 Steel-facing solution, no plate-moulding compo., 143 Steel engravings, preparation of, 167 electrotypes from, 193 Stopping-off compositions, 149 Storing electrotypes, 219 '"TANGENT galvanometer, 93 Temperature of solution, 107 Terminals, 56 Tests for new solution, 109 Thermo-electric batteries, 7 1 battery, Clamond's, 72 Noe's, 74 Thickness of deposit, 192 Tinning metal, 38 trays, 137 process of, 213 Trays, tinning, 137 medallion, 154 TJNDERCUTTINGS, 196 Urquhart's safety current interrupter, 84 resistance scales, 128 medallion trays, 154 WAT, small, 118 large, 122 plan of, 124 Veber, unit of current or quanti- tity, 90 Vessels for alkaline solutions, 129 iron solutions, 130 Volt, unit of electro-motive force, 91 Voltameters, water and copper, 93 "\\fEBER, ,.ait of current, 90 Weston's machine, 88 Wilde's machine, 88 Work and current, relations be- tween, 21 7INC, 37 ' for batteries, 56 to cut, 57 to bend, 57 to amalgamate, 57 THE END. PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, LONDON AND DECCLES. bp tlje same Author. Recently published, with Illustrations, crown 8zv, price $s. doth, ELECTRO-PLATI NG ; A PRACTICAL HANDBOOK. INCLUDING THE PRACTICE OF ELECTRO-TYPING. OPINIONS OF THE PRESS. " The author has carefully thought out his subject, and should be con- sidered by all platers who aim at doing good and lasting work." ENGINEER. " An excellent practical manual." ENGINEERING. " The information given appears to be based on direct personal know- ledge . . . Its science is sound and the style is always clear." ATHENAEUM. " Any ordinarily intelligent person may become an adept in electro deposition with a very little science indeed, and this is the book to show him or her the way." BUILDER. "A large amount of thoroughly practical information. . . . The authoi is at home in dealing with his subject. . . . Undoubtedly a useful work, and one which can be recommended." TELEGRAPHIC JOXTRNAL. " Any amateur will find no difficulty in understanding the book from beginning to end. Everywhere it shows signs of having been drawn up after considerable experience on the part of the author." SPECTATOR. " The volume is without a rival in its particular sphere, and the lucid style in which it is written commends it to those amateurs and experi- mental electrotypers who have but slight, if any, knowledge of the processes of the art to which they turn their attention." DESIGN AND WORK. " A thoroughly practical manual." IRON. "Peculiarly acceptable to those who find it necessary for the conduct of their business that they should be able to do some portion of their electro- plating." JEWELLER AND METALWORKER. " An excellent work, giving the newest information concerning the ever- progressive arts of electro-plating and electro-typing. Evident care has been taken to make the book as useful as possible by including all neces- sary information respecting the preparation of materials and their prices." HOROLOGICAL JOURNAL. " The author handles the subject most lucidly and practically, and the book is printed and illustrated in the good style usual with this firm." WATCHMAKER AND JEWELLER. " The practice of the arts of electro-plating and electro-typing is fol- lowed out through the minutest details, so that the merest amateur may become familiar with the working." DAILY CHRONICLE. " The Handbook is entirely practical ; it is a creditable production, and in matter and manner is a model of what elementary books should be." ARCHITECT. CROSBY LOCKWOOD & CO., 7, Stationers' Hall Court. E.C. fust published, crown 8vo, with 94 Illustrations, price is. 6d. cloth. ELECTRIC LIGHT, ITS PRODUCTION AND USE. EMBODYING PLAIN DIRECTIONS FOR THE WORKING OF GALVANIC BAT' TERIES, ELECTRIC LAMPS, AND DYNAMO-ELECTRIC MACHINES. BY J. W. URQUHART, C.E. AUTHOR OF "ELECTRO-PLATING: A PRACTICAL HANDBOOK..'' EDITED BY F. C. WEBB, M.I.C.E., M.S.T.E. CONTENTS. CHAP. I. INTRODUCTION. II. VOLTAIC BATTERIES. III. THERMO-ELECTRIC BATTERIES. IV. MAGNETO-ELECTRIC GENERATORS. V. ELECTRO -MAGNETO ELECTRIC MACHINES. VI DYNAMO-ELECTRIC MACHINES. VII. GENERAL OBSERVATIONS ON MACHINES. VI1I.-ELECTRIC LAMPS AND CANDLES. IX.-MEASUREMENT OF ELECTRIC LIGHT. X MATHEMATICAL AND EXPERIMENTAL TREATMENT OF THE SUBJECT. XI. APPLICATION AND COST OF THE ELECTRIC LIGHT. TABLES RELATING TO GRAMME'S MACHINES SIEMENS' MACHINES THE WALLACE- FARMER MACHINE WORK OF VARIOUS MACHINES EXPERIMENTS OF THE FRANKLIN INSTITUTE EXPERIMENTS OF THK TRINITY BOARD EFFECTS OF DIFFERENT HINDI OF GLASS COST OF THE ELECTRIC LIGHT COST AT THE BRITISH MUSEUM. LONDON: CROSBY LOCKWOOD & CO., 7, STATIONERS' HALL COURT, LUDGATE HILL, B.C. *** For Opinions of the Press see following fiagcs. OPINIONS OF THE PRESS ON MR. URQUHART'S "ELECTRIC LIGHT." "The art of electric lighting, owing to its very recent introduction, is far from being thoroughly understood, even by some of those engaged in its production. The general public, of course, understand it less ; but to both this work is calculated to prove useful. To the former there is much that will be novel as well as useful, and there are few intelligent men of any class who may not, by a careful perusal of it, be enabled to grasp the principles of the invention at all events gather sufficient facts to enable them to judge between rival systems of electric lighting and between these and gas." IRON. " As a popular work it will doubtless meet with considerable approval. . . . The book can be recommended to those who wish to learn some- thing about the electric light, while the practical information will be found useful to amateurs." ENGLISH MECHANIC. " An interesting volume. . . . The volume is intended to be popular, and is, therefore, prepared in a style to suit the general reader, yet accuracy and systematic arrangement have been as carefully considered as if the book had been intended for the professional man. The work is unques- tionably one that will be extensively read and appreciated, and one, more- over, which may offer important suggestions to inventors who turn their attention to the removal of the few defects still requiring removal in order to make electric illumination generally applicable." MINING JOURNAL. " The book contains a general account of the means adopted in pro- ducing the electric light, not only as obtained from voltaic or galvanic batteries, but treats at length the dynamo-electric machine in several of its forms. . . . We welcome the present volume as an important addition to the literature of the electric light. Students of the subject should no fail to read it." COLLIERY GUARDIAN. " As a practical exposition of the various systems of electric lighting we consider it likely to be useful to the large and increasing class who are interested in the subject." DESIGN AND WORK. " A clear and practical little book." WESTMINSTER REVIEW. " It is the only work at present available which gives in language intel- ligible for the most part to the ordinary reader a general but concise history of the means which have been adopted up to the present time in producing the electric light. . . . The description of these various appliances are just sufficiently full to afford the reader a clear idea of their operation. . . . As a concise history of a vast deal that has already been accomplished, and as a reliable catalogue or list of the appliances at the disposal of those desirous of employing this means of illumination, the work will doubtless be accepted as a valuable addition to the literature at present available on the subject." METROPOLITAN. Opinions of the Press continued. " To those who wish to know the mechanical stages that have marked the progress of electric lighting, no better practical guide could be found than Mr. Urquhart's little work. Himself the inventor of an electric lamp, his practical acquaintance with the subject enables him to give such directions regarding the working of galvanic batteries, electric lamps, and dynamo-electric machines as cannot fail to prove useful to amateur workers in this field, for whom the book seems to have been more especially written." SCOTSMAN. " A volume capable of being made extremely useful by those who have to do with the practical working of electric lamps, galvanic batteries, dynamo-electric machines, and other means of producing electric light. ... A well written, popular, and reliable manual. . . . We have no hesitation to give it a cordial welcome." LEEDS MERCURY. "The book before us shows the steady progress which is being made by electricians, who reasonably conclude, from what has been already accom- plished, that their complete triumph is not far distant. The author enters into full details of the principal systems of electrical illumination that have been recently introduced, and gives practical directions to students and amateurs with reference to the working of galvanic batteries, dynamo- electric machines, electric lamps, and other apparatus, much information being added by the editor, a well-known telegraph engineer, on historical, theoretical, and experimental points. As a popular and practical treatise on the subject the volume may be thoroughly recommended." BRISTOL MERCURY. " Sure of a high place as a handbook and instructor in relation to all matters concerning galvanic batteries, electric lamps, and dynamo-electric machines." LIVERPOOL ALBION. "The present work may be said to be almost exhaustive on the subject of the electric light, so far as its latest developments have gone. The author takes us back to its first appearance in the world of science, and traces its progress through all the stages of its growth, up to the latest improvements of Mr. Edison. ... To all wishing to have before them a lucid explanation of all appertaining to the light of the future, this book may with confidence be recommended." PEOPLE'S FRIEND. " Information about the electric light is usually derived from sensational newspaper paragraphs, and for the most part they are utterly unreliable. The public who have been fed upon this fare would prefer wholesome food if they could get it, but for a long time this was unattainable. They now have a text-book to consult whose authority is indisputable, and whose evidence is brought down to the present month." BRITISH MAIL. LONDON : CROSBY LOCKWOOD & CO., 7, STATIONERS' HALL COURT, LUDGATE HILL, E.G. CROSBY LOCKWOOD & SON'S LIST OF WORKS ON TRADES AND MANUFAC- TURES, THE INDUSTRIAL ARTS, CHEMICAL MANU- FACTURES, COUNTING HOUSE WORK, ETC. A Complete Catalogue of NEW and STANDARD BOOKS relating to CIVIL, MECHANICAL, MARINE and ELECTRICAL ENGINEER- ING; MINING, METALLURGY, and COL- LIERY WORKING; ARCHITECTURE and BUILDING; AGRICULTURE and ESTATE MANAGEMENT, etc. Post Free on Application. 7, STATIONERS' HALL COURT, LONDON, EC. AND 5, BROADWAY, WESTMINSTER, S.W. Messrs. CROSBY LOCKWOOD & SON beg to announce that they have been appointed Agents for the sale of the series of " BOOKS FOR HOME STUDY," issued under the American School of Correspondence, Chicago. These books are both practical and scientific, written by experts whose experience and standing make them authorities on the subjects which they treat. A full descriptive list will be sent post free on application. LIST OF WORKS ON TRADES and MANUFACTURES, THE INDUSTRIAL ARTS, Etc. ACETYLENE, LIGHTING BY. Generators, Burners, and Electric Furnaces. By WILLIAM E. GIBBS, M.E. With 66 Illustrations. Crown 8vo, cloth T/6 AIR GAS LIGHTING SYSTEMS. See PETROL GAS. ALCOHOL (INDUSTRIAL): ITS MANUFACTURE AND USES. A Practical Treatise based on Dr. Max Maercker's "Introduction to Distillation," as revised by Drs. DELBRUCK and LANGE. By T. K. BRACHVOGEL. 500 pages, 105 engravings .... Nef\QIQ THE INDUSTRIAL VALUE OF TAX-FREE ALCOHOL AXD WHAT IT MEANS TO AGRICULTURAL INTERESTS SUMMARY OF THE PROCESSES IN SPIRIT MANUFACTURE- STARCH. How FORMED. ITS CHARACTERISTICS. AND THE CHANGES IT UNDERGOES ENZYMES OR FERMENTS PRODUCTS OF FERMENTATION STARCHY AND SACCHARI- FEROUS RAW MATERIALS PREPARATION OF THE MALT STEAMING THE RAW MATERIAL THE MASHING PROCESS FERMENTING THE MASH PREPARATION OF ARTIFICIAL YEAST IN THE DISTILLERY FERMENTATION IN PRACTICE DISTILLATION AND RECTIFICATION ARRANGEMENT OF THE DISTILLERY THE SPENT WASH DENATURING OF ALCOHOL ALCOHOL FOR THE PRODUCTION OF POWER, HEATING AND ILLUMINATION STATISTICS. ALKALI TRADE MANUAL. Including the Manufacture of Sulphuric Acid, Sulphate of Soda, and Bleaching Powder. By JOHN LOMAS, Alkali Manufacturer. With 232 Illustrations. Super-royal 8vo, cloth. 1 108. BLOWPIPE IN CHEMISTRY, MINERALOGY, Etc. Containing all known Methods of Anhydrous Analysis, many Working Examples, and Instructions for Making Apparatus. By Lieut. -Colonel W. A. Ross, R.A., F.G.S. Second Edition. Crown 8vo, cloth . 6/O BOOT AND SHOE MAKING, including Measurement, Last fitting, Cutting-out, Closing and Making, with a Description of the most Approved Machinery employed. By J. B. LENO. Crown 8vo, cloth 2/O BRASS FOUNDER'S MANUAL. Modelling, Pattern Making, Moulding, Turning, &c. By W. GRAHAM. Crown 8vo, cloth . . 2/O BREAD & BISCUIT BAKER'S & SUGAR-BOILER'S ASSISTANT. Including a large variety of Modern Recipes. By ROBERT WELLS. Fifth Edition. Crown 8vo, sewed. . 1/0- Cloth boards 2/O BREAKFAST DISHES. For every Morning of Three Months. By Miss ALLEN (Mrs. A. MACAIRE). Author of "Savouries and Sweets," &c. Twenty-third Edition. F'cap 8vo. Sewed 1 /O Or, quarter bound, fancy boards . .1/6 CROSBY LOCRWOOD & SON'S CATALOGUE. BREWING, Being a Practical Guide to the Art of Brewing and Malting. Embracing the Conclusions of Modern Research which bear upon the Practice of Brewing. By H. E. WRIGHT, M. A. Third Edition. Thoroughly Revised and Enlarged Large Crown 8 vo, 578 pp., cloth . . Net 1 2/6 BARLEY, MAI.TIM; AND MALT WATRR FOR BREWING Hops AND SUGARS THE BREWING ROOM CHEMISTRY AS APPLIED TO BREWING 'I'm; I. ABOKATORY MASHING, -SPARGING, AND BOILING FERMENTS IN GENERAL FERMENTATION WITH COMMERCIAL YEAST CULTURE i ROM A SINGLE CELL WITH YEASTS TREATMENT or BIIER THE BREWERY AND PLANTS. CALCULATOR, NUMBER, WEIGHT AND FRACTIONAL. Containing upwards of 250,000 Separate Calculations, showing at a Glance the Value at 42?. Different Rates, ranging from j-J 4 th of a Penny to 2os. each, or per cwt. , and 20 per ton, of any number of articles consecutively, from i to 470. Any number of cwts., qrs., and lbs.,from i cwt. to 470 cwts. Any number of tons, cwts., qrs., and Ibs., from i to 1,000 tons. By WILLIAM CHADWICK, Public Accountant. Fifth Edition, Revised and Improved. 8vo, strongly bound 1 8/O CEMENTS, PASTES, GLUES, AND GUMS. A Guide to the Manufacture and Application of Agglutinants for Workshop, Laboratory, or Office Use. With goo Recipes and Formulae. By H. C. STANDAGE. Crown 8vo, cloth 2/O "As a revelation of what are considered trade secrets, tliis uouk will arouse an amount of curiosity among the large number of industries it touches." Daily Chronicle. CHEMISTRY FOR ARMY AND MATRICULATION CANDIDATES. By GEOFFREY MARTIN, B.Sc., Ph.D. Crown 8vo, cloth. With numerous Illustrations Net 2/O PREPARATION AND USE OK APPARATUS PREPARATION AND PROPERTIES OF CERTAIN GASES AND LIQUIDS SIMPLE QUANTITATIVE EXPERIMENTS ANALYTICAL OPERATIONS SOLUBILITY WATER CRYSTALLISATION NEUTRALISATION OF ACIDS BY KASES, AND PREPARATION OF SIMPLE SALTS VOLUMETRIC ANALYSIS CHEMICAL F.QUIVALENTS OBSERVATION OF REACTION MELTING AND BOILING POINTS SYMBOLS AND ATOMIC WEIGHTS OK THE ELEMENTS WEIGHTS AND MEASURES HINTS ON REGULATING WORK IN PRACTICAL CHEMISTRY CLASSES. CHEMISTRY: INDUSTRIAL AND MANUFACTURING CHEMISTRY (Organic). By GEOFFREY MARTIN, Ph D., M.Sc., B.Sc.. F.C.S., assisted by Fourte n Specialists. 700 pages, 250 Illustrations. Royal 8 vo, cloth . \JnstPublished. Net 2 "I/O ** This work covers the whole range of subjects with which the industrial chemist and manufacturer are usually concerned, and meets the requirements of all business and practical men interested in Chemical Processes, of Manufacturers, Consulting Chemists, Chemical Engineers, Students in Technical Institution, &c.,&c. The following Specialists have assisted in the compilation of the work : Wm. Barbour, M.A., B.Sc., F.I C. ; T. Beacall, B. A. ; A. J. Carrier, B.Sc. ; F. Challenger, Ph.D., B.Sc., A. I.C. ; E. A. Dancaster, B Sc. ; J. Newton Friend, D.Sc., Ph.D. ; W. Goodwin, M.Sc., Ph.D. ; C. H. Griffiths, Brtw, Eng. ; G. Druce Lander, D.Sc., Ph.D.,F.I.C. ; D. B. Law, B.Sc., F.I. C.; C. A. Mitchell, B.A., F.I.C. ; H. S. Sand, Ph.D., D.Sc. ; Arthur Slator, Ph.D., D.Sc. F.I.C. ; W. H. Stephens, A.R.C.S. LIST OF SECTIONS. i. THE OIL, FAT, VAKNISH AND SOAP 13. INDUSTRY OF SYNTHETIC DYB STUFFS. INDUSTRY. 2. THE SUGAR INDUSTRY. 3. THE STARCH INDUSTRY. 4. THE CELLULOSE INDUSTRY. 5. THE FERMENTATION INDUSTRIES. 6. THECHARCOALANDWOODDISTILLING INDUSTRY. 7. THE TURPENTINE AND ROSIN INDUSTRY. 8. INDUSTRIAL GUMS AND RUSINS. 9. THE RUBBER INDUSTRY, 10. THE INDUSTRY OF ALIPHATIC CHEMICALS. it. THE ILLUMINATING GAS INDUSTRY. 12. THE COAL TAR AND COAL TAR PRO- DUCT INDUSTRY. INDUSTRY OF NATURAL DYE STUFFS. 15. THE INK INDUSTRY. 16. THE PIGMENT AND PAINT INDUSTRY. 17. THE TEXTILE FIBRE, BLEACHING AND WATERPROOFING INDUSTRIES. 18. DVEING AND COLOUR PRIMING INDUSTRIES. 19. THE LEATHER AND TANNING INDUSTRY. 20. THE GLUE, GELATINE AND ALBUMEN- INDUSTRY. 21. THE INDUSTRY OF MODBRNSYHTHBTIC AND OTHER DRUGS. -z. MODERN EXPLOSIVE INDUSTRY. 23. INDUSTRY OF PHOTOGRAPHIC CHEMICALS. [Complete Prospectus on Application.} TRADES <& MANUFACTURES, INDUSTRIAL ARTS, & f . 5 CLOCKS, WATCHES, & BELLS for PUBLIC PURPOSES. By EDMUND BECKETT, LORD GRIMTHORPE, LL.D., K.C., F.R.A.S. Eighth Edition, with new List of Groat Bells and an Appendix on Weathercocks. Crown 8vo, cloth ....... 4/6 ; cloth boards, 5/6 COACH-BUI LDLNQ. A Practical Treatise, Historical and Descriptive. By J. W. BURGESS. Crown 8vo, cloth . . . 2/6 COKE MODERN COKING PRACTICE. Including the Analysis of Materials and Products. A handbook for those engaged or interested in Coke Manufacture with recovery of By-Products. By T. H. BYROM, IM.C., F.C.S., Mem. Soc. ofChem. Industry, Chief Chemist to the Wigan Coal and Iron Company. For fifteen years Lecturer at the Wigan Technical College. Author of "The Physics and Chemistry of Mining" ; and J. E. CHRISTOPHER, Mem. Soc. of Chem. Industry, Sub-manager of the Semet Solvay Coking Plant of the Wigan Coal and Iron Company. Lecturer on Coke Manufacture at the Wigan Technical College. 168 pages, with numerous illustrations. Demy 8vo, cloth. . . . Net 8/6 " The authors have succeeded in treating the subject in a clear and compact way, giving an easily comprehensible review of the different processes." Mining yoiinia/. "The book will be eagerly read, and the authors may be assured that their labour will be appreciated. We anticipate tnt the book will be a success ; at any rate it possesses thenecessary merit." Science anti Art of Mining: COMMERCIAL CHEMISTRY. See MARTINS INDUSTRIAL CHEMISTRY, p. 4. Being COMMERCIAL CORRESPONDENT, FOREIGN. CONFECTIONER, MODERN FLOUR. Containing a large Collection of Recipes for Cheap Cakes, Biscuits, &c. Wi'h remarks on the Ingredients Used in their Manufacture. By R. WELLS. Sewed. . "I/O Cloth boards 2/O CONFECTIONERY, ORNAMENTAL. A Guide for Bakers, Confectioners and Pastrycooks ; including a variety of Modern Recipes, and Remarks on Decorative and Coloured Work. With 129 Original Designs. By ROBERT WELLS. Crown 8vo, cloth 5/O COTTON MANUFACTURE. A Manual of Practical Instruc- tion of the Processes of Opening, Carding, Combing, Drawing, Doubling and Spinning, Methods of Dyeing, &c. For the Use of Operatives, Overlookers, and Manufacturers. By J. LISTER. 8vo, cloth . . 7/8 CRUSHING AND GRINDING MACHINERY PRACTICE. A Handbook on the Machinery used in Crushing and Grinding Operations on all classes of materials. Including also a Glossary of Technical Terms and Bibliography. By THOMAS G. MARLOW, Grinding, Drying and Separating Machinery Specialist. Author of " Drying Machinery and Practice." With numerous Tables, Plates and Illustrations ... [In the Piess. DANGEROUS GOODS. Their Sources and Properties, Modes of Storage and Transport. With Notes and Comments on Accidents arising therefrom. For the Use of Government and Railway Officials, Steamship Owners, &c. By H. J. PHILLIPS. Crown 8vo, cloth .... 9/O DENTISTRY (MECHANICAL). A Practical Treatise on the Construction of the Various Kinds of Artificial Dentures. By C. HUNTER. Crown Svo, cloth 3 O CROSBY LOCKWOOD & SON'S CATALOGUE. DISCOUNT GUIDE. Comprising several Series of Tables for the Use of Merchants, Manufacturers, Ironmongers, and Others, by which may be ascertained the Exact Profit arising from any mode of using Discounts, either in the Purchase or Sale of Goods, and the method of either Altering a Rate of Discount, or Advancing a Price, so as to produce, by one operation, a sum that will realise any required Profit after allowing one or more Discounts : to which are added Tables of Profit or Advance from ij to 90 per cent., Tables of Discount from ij to gSJ per cent., and Tables of Commission, &c., from i to 10 per cent. By HENRY HARBKN, Accountant. New Edition, Corrected. Demy 8vo, half-bound 1 5s. DRYING MACHINERY AND PRACTICE. A Handbook on the Theory and Practice of Drying and Desiccating, with Classified Descrip- tion of Installations, Machinery, and Apparatus, including also a Glossary of Technical Terms and Bibliography. r!y THOMAS G. MARLOW, Grinding, Drying, and Separating Machinery Specialist. 340 pages, with numerous Tables, Plates, and Illustrations. Medium 8vo, cloth Net 1 2/6 ELECTRICITY IN FACTORIES AND WORKSHOPS: ITS COST AND CONVENIENCE. A Handbook for Power Producers and Power Users. By A. P. HASLAM, M.I.E.E. 328 pages, with numerous illustrations. Large crown, 8vo, cloth Net 7/6 ELECTRO-METALLURGY. A Practical Treatise. By ALEX- ANDER WATT. Tenth Edition, enlarged and revised. Including the most Recent Processes. Crown 8vo, cloth 36 ELECTRO-PLATING. A Practical Handbook on the Deposition of Copper, Silver, Nickel, Gold, Aluminium, Brass, Platinum, &c., &c. By J. W. URQUHART, C.E. Sixth Edition. Crown 8vo, cloth . . 5/O ELECTRO-PLATING &ELECTRO-REFINING OF METALS Being a new edition of ALEXANDER WATT'S " ELECTRO-DEPOSITION." Re- written by A. PHILIP, B.Sc., Principal Assistant to the Admiralty Chemist. Second Edition, Revised. 700 pages, with 160 illustrations. Large Crown 8vo, cloth Net 1 2/6 PART I. ELECTRO-PLATINGPRELIMINARY CONSIDERATIONS PRIMARY AND SECONDARY BATTERIES THERMOPILES DYNAMOS COST OF ELECTRICAL INSTALLA- TIONS OF SMALL OUTPUT FOR ELECTRO-PLATINGHISTORICAL REVIEW OF ELECTRO DEPOSITION ELECTRO DEPOSITION OF COPPER DEPOSITION OF GOLD BY SIMPLE IMMERSION ELECTRO DEPOSITION OF GOLD VARIOUS GILDING OPERATIONS MER- CURY GILDING tELECTRo DEPOSITION OF SILVER IMITATION ANTIQUE SILVER- ELECTRO DEPOSITION OF NICKEL. TIN, IRON AND ZINC, VARIOUS METALS AND ALLOYS RECOVERY OF GOLD AND SILVER FROM WASH SOLUTIONS MECHANICAL OPERATIONS CONNECTED WITH ELECTRO DEPOSITION MATERIALS USED IN ELECTRO DEPOSITION. PART II. ELECTRO METALLURGY ELECTRO METALLURGY OF COPPER COST OF ELECTROLYTIC COPPER REFINING CURRENT DENSITY AS A FACTOR IN PROFITS SOME IMPORTANT DETAILS IN ELECTROLYTIC COPPER REFINERIES ELECTROLYTIC GOLD AND SILVER BULLION REFINING ELECTROLYTIC TREATMENT OF TIN ELECTROLYTIC REFINING OF LEAD ELECTROLYTIC PRODUCTION OF ALUMINIUM AND ELECTROLYTIC REFINING OF NICKEL ELECTRO GALVANISING. ELECTRO-TYPING. The Reproduction and Multiplication of Printing Surfaces and Works of Art by the Electro-Deposition of Metals. By J. W. URQUHART, C.E. Crown 8vo, cloth 6/O ENGINEERING CHEMISTRY. A Practical Treatise for the Use of Analytical Chemists, Engineers, Iron Masters, Iron ^Founders, Students and others. Comprising Methods of Analysis and Valuation of the Principal Materials used in Engineering Work, with numerous Analyses, Examples and Suggestions. By H. PHILLIPS. Third Edition, Revised. Crown 8vo, 420 pp., with Illustrations, cloth .... Net 1 Q/8 TRADES & MANUFACTURES, INDUSTRIAL ARTS.S-c. 7 EXPLOSIVES, MODERN, A HANDBOOK ON. A Prac- tical Treatise on the Manufacture and Use of Dynamite, Gun-Cotton, Nitro-Glycerine and other Explosive Compounds, including Collodion-Cotton. With Chapters on Explosives in Practical Application. By M. EISSLER, M.E. Second Edition, Enlarged. Crown 8vo, cloth ..... 1 22/6 EXPLOSIVES: NITRO-EXPLOSIVES. The Properties, Manufacture, and Analysis of Nitrated Substances, including the Fulminates, Smokeless Powders, and Celluloid. By P. G. SANFORD, F.I.C., F.C.S., Public Analyst to the Borough of Penrance. Second Edition, enlarged. With Illustrations. Demy 8vo, cloth ....... Net 1 Q/6 NITRO-GLYCERINE XITRO-CEI.I.UI.OSR, ETC. DYNAMITE NITRO-BENZOL, Ro- BUR1TR, BEI.LITK, PICRIC ACID, ETC. THE FULMINATES S.MOKIil.KSS POWDERS IN GENERAL ANALYSIS oi' EXPLOSIVES FIRING POINT, HEAT TESTS, DETERMINATION OF RELATIVE STRENGTH, ETC. " One of the very few text-books In which can be found just what Is wanted. Mr. Sanford goes steadily through the whole list of explosives commonly used, he names any given explosive, and tells of what it is composed and how It is manufactured. The book Is excellent." Bnginttr. FACTORY ACCOUNTS : THEIR PRINCIPLES AND PRACTICE. A Handbook for Accountants and Manufacturers, with Appendices on the Nomenclature of Machine Details, the Income Tax Acts, the Rating of Factories, Fire and Boiler Insurance, etc., including a Glossary of Terms and a large number of Specimen Rulings. By EMILE GARCKE and J. M. FELLS. Sixth Edition, Revised and considerably extended. 314 pages. Demy 8vo, cloth . . . Net 6/O " A very Interesting description of the requirements of Factory Accounts. . . . The principle of assimilating the Factory Accounts to the general commercial books Is one which we thoroughly agree with." Accountants' yournal. FLOUR MANUFACTURE. A Treatise on Milling Science and Practice. By FRIKDRICH KICK, Imperial Regierungsrath, Professor of Mechanical Technology in the Imperial German Polytechnic Institute, Prague. Translated from the Second Enlarged and Re_vised Edition. By H. H. P. POWLES, A.M.Inst4C.E. 400 pp., with 28 Folding Plates, and 167 Woodcuts. Royal 8vo, cloth .......... 1 5s. FRENCH POLISHING AND ENAMELLING. Including numerous Recipes for making Polishes, Varnishes, Glaze, Lacquers, Revivers, &c. By R. BITMEAD. Crown 8vo, cloth . . . .1/6 FRETCUTTING, THE ART OF MODERN. 150 pages, with numerous Illustrations. Crown 8vo, cloth. [Just Published. Net 1/6 QAS ENGINEER'S POCKET-BOOK* Comprising Tables, Notes and Memoranda relating to the Manufacture, Distribution and Use of Coal Gas and the Construction of Gas Works. By H. O'CONNOR, A.M.Inst.C.E. Third Edition. Revised. Crown 8 vo, leather. GENERAL CONSTRUCTING MF.MORANDA GENERAL MATHEMATICAL TABLES UNLOADING MATERIALS AND STORAGE RETORT HOUSE CONDENSERS BOILERS, ENGINES. PUMPS, AND EXHAUSTERS SCRUBBERS AND WASHERS PURIFIERS GASHOLDER TANKS-GASHOLDERS WOR1CSHOF NOTES MANUFACTURING STORIHC MATERIALS RETORT HOUSE (WORKING) CONDENSING GAS EXHAUSTERS, ETC. WASHING AND SCRUBBING PURIFICATION GASHOLDERS (CARE OF) DISTRIBUTING GAS TESTING ENRICHING PROCESSES PRODUCT WORKS SUPPLEMENTARY. "The book contains a vast amount of Information." Gas IVorlJ. GAS ENGINEERING. See PRODUCER GAS PRACTICE AND INPUSTRIAL GAS ENGINEERING. CROSBY LOCK WOOD * SON'S CATALOGUE. GAS FITTING. A Practical Handbook. By JOHN BLACK. Revised Edition. With 130 Illustrations. Crown 8vo, cloth . 2/6 GAS LIGHTING. See ACETYLENE. GAS LIGHTING FOR COUNTRY HOUSES. See PETROL AIR GAS. GAS MANUFACTURE, CHEMISTRY OF. A Practical Manual for the use of Gas Engineers, Gas Managers and Students. By HAROLD M. ROYLE, Chief Chemical Assistant at the Beckton Gas Works. Demy 8vo, cloth, 340 pages, with numerous Illustrations and Coloured Plate. Net 1 2/6 PREPARATION OF STANDARD SOLUTIONS ANALYSIS OF COALS DF.SCRIPTION OF VARIOUS TYPF.S OF FURNACES PRODUCTS OF CARBONISATION AT VARIOUS TEMPERA- TURESANALYSIS OF CRUDE GAS ANALYSIS OF LIME ANALYSIS OF AMMONIACAL LIQUOR ANALYTICAL VALUATION OF OXIDE OF IRON ESTIMATION OF NAPHTHALIN ANALYSIS OF FIRE-BRICKS AND FIRE-CLAYART OF PHOTOMETRY CARBURETTED WATER GAS APPENDIX CONTAINING STATUTORY AND OFFICIAL REGULATIONS FOR TESTING GAS. VALUABLE EXCERPTS FROM VARIOUS IMPORTANT PAPERS ON GAS CHEMISTRY, USEFUL TABLES, MEMORANDA, ETC. GAS WORKS. Their Construction and Arrangement, and the Manufacture and Distribution of Coal Gas. By S. HUGHES, C.E. Ninth Edition. Revised by H. O'CONNOR, A. M.Inst.C.E. Crown 8vo . 6/O GOLD WORKING. JEWELLER'S ASSISTANT for Masters and Workmen, Compiled from the Experience of Thirty Years' Workshop Practice. By G. E. GEE. Crown 8vo 7/6 GOLDSMITH'S HANDBOOK. Alloying, Melting, Reducing, Colouring, Collecting, and Refining. 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ILLUMINATING AND MISSAL PAINTING ON PAPER AND VELLUM. A Practical Treatise on Manuscript Work, Testimonials, and Heiald Painting, with Chapters on Lettering and Writing, and on Mediaeval Burnished Gold. With two Coloured Plates. By PHILIP WHiTHARD(First-class Diploma for Illumination and Herald Painting, Printing Trades Exhibition, 1006). New and Cheaper Edition. 156 pages. Crown 8vo, sewed. {Just Published. Net 1/6 TRADES &- MANUFACTURES, INDUSTRIAL ARTS.frc. g INDUSTRIAL AND MANUFACTURING CHEMISTRY. I V 3> 3i. 3i. 4. 4i. 4?, and 5 per cent. By A. M. CAMPBELL Author of" The Concise Calendar." Crown 8vo, cloth Net 2/6 IRON AND METAL TRADES' COMPANION. For Expeditiously ascertaining the Value of any Goods bought or sold by Weight, from is. per c\vt. to 112$. percwt., and from one farthing per pound to one shilling per pound. By THOMAS DOWNIE. Strongly bound in leather, 396 pp 9 Q " A most useful set of tables. 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WRIGHT, M.A.Oxon., B.Sc.Lond., formerly Assistant Lecturer in Chemistry at the Yorkshire College, Leeds, and Lecturer in Chemistry at the Hull Technical School. Demy 8vo, cloth Net QIQ THE OCCURRENCE AND COMPOSITION OF OILS, FATS, AND WAXES THE PHYSICAL PROPERTIES OF OILS, I-"ATS, AND \\'AXI;S, AND THEIR DETERMINATION THH CHEMICAL PROPERTIES OF OILS, FATS, AND WAXES FROM THE ANALYTICAL STANDPOINT DETECTION AND DETERMINATION OF NON-FATTY CONSTITUENTS METHODS FOR ESTIMATING THE CONSTITUENTS OF OILS AND FATS DESCRIPTION AND PROPERTIES OF THE MORE IMPORTANT OILS, FATS, AND WAXES, WITH THE METHODS I-OR THEIR INVESTIGATION EXAMINATION OF CERTAIN COMMERCIAL PRODUCTS. ORGAN BUILDING (PRACTICAL). By W. E. DICKSON, M.A., Precentor of Ely Cathedral. Second Edition, Crown 8vo . 2/6 PAINTS, MIXED. THEIR CHEMISTRY AND TECH- NOLOGY. By MAXIMILIAN TOCH. With 60 Photomicrographic Plates and other Illustrations Net "| 2/6 THE PIGMENTS YELLOW, BLUE, AND GREEN PIGMENTS THE INERT FILLERS AND EXTENDERS PAINT VEHICLES SPECIAL PAINTS ANALYTICAL APPENDIX. PAINTING FOR THE IMITATION OF WOODS AND MARBLES. As Taught and Practised by A. R. VAN DER BURG and P. VAN DER BURG, Directors of the Rotterdam Painting Institution. Royal folio, cloth, i8J by izj in. Illustrated with 24 full-size Coloured Plates ; also 12 Plain Plates, comprising 154 Figures. Fifth Edition . . Net 25/O PAINTING, GRAINING, MARBLING, AND SIGN WRITING. With a Course of Elementary Drawing and a Collection of Useful Receipts. By E. A. DAVIDSON. Ninth Edition. Coloured Plates. Crown 8vo, cloth, 5/O > cloth boards, 6/O PAPER-MAKING. A Practical Manual for Paper Makers and Owners and Managers of Paper-Mills. With Tables, Calculations, etc. By G. CLAPPKRTON, Paper-Maker. With Illustrations of Fibres from Micro- Photographs. Second edition, revised and enlarged. Crown 8vo, cloth Net 6/O CHEMICAL AND PHYSICAL CHARACTERISTICS OF VARIOUS FIBRES CUTTING AND BOILING OF RAGS JUTE BOILING AND BLEACHING WET PICKING WASHING, BREAKING, AND BLEACHING ELECTROLYTIC BLEACHING ANTICHLOR CELLULOSE FROM WOOD MECHANICAL WOOD PULP ESPARTO AND STRAW BEATING LOADING STARCHING COLOURING MATTER RESIN, SIZE, AND SIZING THE FOURDRINIER MACHINE AND ITS MANAGEMENT ANIMAL SIZING DRYING GLAZING AND BURNISHING CUTTING, FINISHING MICROSCOPICAL EXAMINATION OF PAPER TESTS FOR IN- GREDIENTS OF PAPER RECOVERY OF SODA TESTING OF CHEMICALS TESTING WATER FOR IMPURITIES. PAPER-MAKING. A Practical Handbook of the Manufacture of Paper from Rags, Esparto, Straw, and other Fibrous Materials. Including the Manufacture of Pulp from Wood Fibre, with a Description of the Machinery and Appliances used. To which are added Details of Processes for Recovering Soda from Waste Liquors. By A. WATT. With Illustrations. Crown Svo . 7/6 CROSBY LOCK WOOD * SON'S CATALOGUE. PAPER MAKING, CHAPTERS ON. A Series of Volumes dealing in a practical manner with all the leading questions in connection with the Chemistry of Paper-Making and the Manufacture of Paper. By CLAYTON BEADLE, Lecturer on Paper-Making before the Society of Arts, 1898 and 1902, and at the Battersea Polytechnic Institute, 1902, etc., etc. Each volume is published separately, at the price of 5/O *"' per vol. Volume I. comprises a Series of Lectures delivered on behalf of the Battersea Polytechnic Institute in 1902. Crown 8vo. 151 np. ffet 5/O Volume II. comprises Answers to Questions on Paper-Making Set by the Examiners to the City and Guilds of London Institute, 1901-1903. Grown 8vo, 182 pp. Net S/Q Volume III. comprises a short practical Treatise in which Boiling, Bleaching, Loading, Colouring, and similar Questions are discussed. Crown 8vo, 142 pp Net Q/Q CONTENTS :" BRASS" AND "STEHL" BEATER BARS THE SIZE AND SPEED OF BEATER ROLLS THE FADING OF PRUSSIAN BLUE PAPERS THE EFFECT OF LOWERING THE BREAST ROLL- THE EFFECT OF "LOADING" ON THE TRANSPARENCY OF PAPER " TERRA ALBA " AS A LOADING FOR PAPERTHE USE OF ALUM IN TUB SIZING THE INFLUENCE OF TEMPERATURE ON BLEACHING THE USE OF REFINING ENGINES- AGITATION AS AN AUXILIARY TO BLEACHING THE. HEATING OF "STUFF" FOR TIIK PAPER MACHINE THE COMPARATIVE RESULTS OF QUADRUPLE AND OPEN EFFECT EVAPORATION HOW TO PREVENT ELECTRIFICATION OF PAPER ON THE MACHINF. TRANSPARENCY OF PAPERS THE LIFE" OF MACHINE WIRES EDGE RUNNERS. Volume IV. contains discussions upon Water Supplies and the Management of the Paper Machine and its influence upon the Qualities of Papers. Crown 8vo, 164 pp Net 5/O CONTENTS: THE BULKING OF PAPERS SPECIAL QUALITIES OF "ART" PAPF.RS THE "AGEING" AND STORAGE OF PAPERS THE USE OF LIME IN BOILING CONTROL- LING THE MARK OF THE "DANDY" "MACHINE" AND "HAND" CUT RAGS FROTH ON PAPER MACHINE SCUM SPOTS IN PAPER CONSUMPTION OF WATER IN THE MANUFAC- TURE OF PAPER THE MANAGEMENT OF SUCTION-BOXES THE SHRINKAGE OK PAPER ON THE MACHINE PAPER THAT DOES NOT SHRINK OR EXPAND THB PRODUCTION OF NON-STRETCHABLE PAPER THE CONNECTION BETWEEN " STRETCH " AND " EXPANSION " OF PAPERS "STRETCH " AND " BREAKING STRAIN" PAPER TESTING MACHINES. Volume V. concerning THE THEORY AND PRACTICE OF BEATING. Crown 8vo. With photomicrographs and other Illustrations. Net 5/O CONTENTS: EARLY BEATING APPLIANCES THE HOLLANDER THE ECONOMY OF BEATING DIFFICULTIES OF ARRIVING AT DEFINITE RESULTS BEHAVIOUR OF DIFFERENT FIBRES " REFINING "- POWER CONSUMPTION A COMPARISON OF TWO DIFFERENT KINDS OF BEATERS POWER CONSUMED IN THE " BREAKING," " BEATING," AND "REFINING" OF DIFFERENT MATERIALS DEALING WITH THE "CIRCULATION" AND "AGITATION" IN A HOLLANDER COMPARISONS OF LARGE AND MEDIUM-SIZED HOLLANDERS WHEN BEATING "HARD" AND "SOFT" STOCK TRIALS TO DETERMINE THE RELATIVE MERITS OF STONE AND METAL BEATER-BARS TRIALS WITH BREAKERS, REED BEATERS, AND KINGSI.AND REFINERS A SYSTEM OF BEATING COMBINED WITH A SYSTEM FOR CONTINUOUS BLEACHING BEATERS AND REFINERS POWER CONSUMED IN GRINDING WOOD-PULP THE REDUCTION IN LENGTH OF FIBRES AT DIFFERENT STAGES OF BEATING METHOD FOR DETERMINING THE WETNESS" OF BEATEN STUFF THE POSITION OF BEATERS IN OLD AND MODERN PAPER-MILLS APPENDIX. PASTRYCOOK AND CONFECTIONER'S GUIDE. For Hotels, Restaurants, and the Trade in general, adapted also for Family Use. By R. WELLS, Author of " The Bread and Biscuit Baker." Sewed 1/O i cloth boards 2/O PETROL AIR GAS. A Practical Handbook on the Installation and Working of Air Gas Lighting Systems for Country Houses. By HENRY O'CONNOR, F.R.S.E., A.M.Inst.C.E., &c., author of " The Gas Engineer's Pocket Book." Second Edition Revised. 100 pages with illustrations. Crown 8 vo, cloth. [Just Published. Ntt -\/Q TRADES &> MANUFACTURES, INDUSTRIAL ARTS, &>c. 13 PETROLEUM. THE OIL FIELDS OF RUSSIA AND THE RUSSIAN PETROLEUM INDUSTRY. A Practical Hand book on the Exploration, Exploitation, and Management of Russian Oil Properties, the Origin of Petroleum in Russia, the Theory and Practice of Liquid Fuel. By A. B. THOMPSON, A.M.I. M.E., F.G.S. 415 pp., with numerous Illustrations and Photographic Plates. Second Edition Revised. Super-royal 8 vo, cloth Net 2 "I/O PETROLEUM MINING AND OIL-FIELD DEVELOP- MENT. 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Showing their Com- position, Conditions of Permanency, Non-Permanency, and Adulterations, ttc., with Tests of Purity. By H. C. STANDAGE. Third Edition. Crown 8vo, cloth 2/6 PORTLAND CEMENT, THE MODERN MANUFACTURE OF. A Handbook for Manufacturers, Users, and all interested in Portland Cement._ By PEKCY C. H. WEST, Fellow of the Chemical Society and of the Society of Chemical Industry. Vol. I. Machinery and Kilns. 280 pages, with 159 Illustrationsand numerous Tables. Royal 8vo, cloth. Net "1 2/6 WASH-MILLS WBT EDGE-RUNNERS AND STONH-MlLLS WET TUBE-MILLS OTHER WET MILLS AND ACCESSORY PLANT WET PROCESS CRUSHERS DRIERS MILLSTONES, KUGE-KUNNERS, DISINTEGRATORS, &c. 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Demy 410, cloth I Net 25/- PRODUCER OPERATION CLEANING THE GAS WORKS DETAILS PRODUCER TYPES MOVING CASKS SOLID FUELS PHYSICAL PROPERTIES OF GASES CHEMICAL PRO- PERTIES OK GASES GAS ANALYSIS GAS POWER GAS ENGINES INDUSTRIAL GAS APPLICATIONS FURNACES AND KILNS BURNING LIME AND CEMENT PRE-HEATING AIR DOHERTY COMBUSTION ECONOMISER COMBUSTION IN FURNACES HEAT: TEMPERATURE, RADIATION AND CONDUCTION HEAT MEASUREMENTS : PYROMETRY AND CALORIMETRY PIPES, FLUES, AND CHIMNEYS MATERIALS : FIRE CLAY MASONRY, WEIGHTS AND ROPE USEFUL TAPLES OIL FUEL PRODUCER GAS. RECIPES, FORMULAS AND PROCESSES, TWEN- TIETH CENTURY BOOK OF. Edited by GARDNER D. Hiscox, M.E. Nearly 10,000 Scientific, Chemical, Technical, and Household Recipes, Formulas and Processes for Use in the Laboratory and the Office, the Workshop and the Home. Medium 8vo, 800 pp., cloth. . Net 12/6 SELECTED LIST OF CONTENTS: ABSINTHE ACID PROOFING ADHESIVES ALCOHOI ALKALI ALLOYS ALUMINIUM AMMONIA ANILINE ANTIDOTES FOR POISON ANCHOVY PREPARATIONS ANTISEPTICS ANTIQUES BAKING POWDERS- BAROMETERS BEVERAGES BLEACHING BRASS BRICK CARBOLIC ACIDS CASTING CELLULOID CHEESE CERAMICS CIGARS COFFEE CONDIMENTS COPI-KR COSMETICS COTTON DIAMOND TESTS DONARITE DYES ELECTRO PLATING- EMBALMING KNAMELLING ENGRAVING ESSENCES EXPLOSIVES FERTILISERS FILTERS FOOD ADULTERANTS GELATINE GLASS GOLD GUMS HARNESS DRESS- INGS HORN INKS INSECTICIDES IRON IVORY JEWKLLERS' FORMULAS LACQUERS LAUNDRY PREPARATIONS LEATHER LINOLEUM LUBRICANTS MATCHES METALS Music BOXES OILS PAINTS PAPER PERFUMES PETROLEUM PHOTOGRAPHY- PLASTER PLATING POLISHES PORCELAIN POULTRY PUTTY RAT POISONS REFRIGERATION ROPES RUBBER RUST PREVENTIVES SALT SCREWS SILK- SILVER SOAPS SOLDERS SPIRIT SPONGES STEEL STONE THERMOMETERS TIN VALVFS VARNISHES VETERINARY FORMULAS WATCHMAKERS' FORMULAS WATERPROOFING WAXWEIGHTS AND MEASURES WHITEWASH WOOD YEAST. CROSBY LOCKWOOD & SON'S CATALOGUE. RUBBER HAND STAMPS. And the Manipulation of Rubber. A Practical Treatise on the Manufacture of Indiarubber Hand Stamps, Small Articles of Indiarubber, The Hektograph, Special Inks, Cements, and Allied Subjects. By T. O'ConoR SLOANE, A.M., Ph.D. With numerous Illustra- tions. Square 8vo, cloth 6/O RUBBER. ITS CULTIVATION AND PREPARATION. By W. H. JOHNSON, F.L.S., Director of Agriculture, S. Nigeria, West Africa, Commissioned by Government in 1902 to visit Ceylon to Study the Methods employed there in the Cultivation and Preparation of Para Rubber and other Agricultural Staples for Market, with a view to Introduce them into West Africa. Second Edition, rewritten and greatly enlarged, with numerous illustrations. Demy 8vo, cloth Net 7/6 THE WORLD'S PRODUCTION AND CONSUMPTION OF KUBHKR THE PARA RUBBER TREE AT HOMB AND ABROAD PROPAGATION PLANTING AND CULTIVATING SOILS AND MANURES PESTS LATEX COLLECTING THE LATEX RUHBHR MANUFACTURE THE ANTISKPTICISATION OK RUBBER DRYING AND PACKING RTBIMIK i OK KXPORT YIELD OF PARA RUBBER FROM CULTIVATED TREES ESTABLISHMENT AND MAIN- TENANCE OF A PARA RUBBER PLANTATION COMMERCIAL VALUE OF THE OIL IN HEVEA SEEDS. RUBBER PLANTER'S NOTE-BOOK. A Handy Book of Reference on Para Rubber Planting. With Hints on the Maiutenanae of Health in the Tropics, and other general information of utility to the Rubber Planter. Specially designed for use in the Field. Compiled from the most reliable and modern sources by FRANK BRAHAM, F. R.G.S. 116 pages. With diagrams and illustrations. F'cap 8vo, cloth net 2/6 SAVOURIES AND SWEETS. Suitable for Luncheons and Dinners. By Miss M. L. ALLEN (Mrs. A. MACAIRE), Author of " Break- fast Dishes," etc. Thirty-first Edition. F'cap 8vo, sewed . . . 1 /O Or, quarter bound, fancy boards . .1/6 SHEET METAL-WORKER'S GUIDE. A Practical Hand- book for Tinsmiths, Coppersmiths, Zincworkers, &c., with 46 Diagrams and Working Patterns. By W. J. E. CRANE. Crown 8vo, Cloth . .1/8 SHEET METAL - WORKER'S INSTRUCTOR. Com- prising Geometrical Problems and Practical Rules for Describing the Various Patterns Required by Zinc, Sheet-Iron, Copper, and Tin-Plate Workers. By R. H. WARN. Third Edition. Revised and Further Enlarged by J. G. HORNER, A.M.I.M.E. Crown 8vo, 280 pp., with 465 Illustrations, cloth 7/6 SILVERSMITH'S HANDBOOK. Alloying and Working of Silver, Refining and Melting, Solders, Imitation Alloys, Manipulation, Prevention of Waste, Improving and Finishing the Surface of the Work, etc. By GEORGE E. GEE. Fourth Edition Revised. Crown 8vo, cloth 3/O SOAP-MAKINQ. A Practical Handbook of the Manufacture of Hard and Soft Soaps, Toilet Soaps, etc. With a Chapter on the Recovery of Glycerine from Waste Leys. By ALEXANDER WATT. Seventh Edition, including an Appendix on Modern Candlemaking. Crown 8vo, cloth i /6 "The work will prove very useful, not merely to the technological student, but to the soap boiler who wishes to understand the theory of his art." Chemical News. SOAPS, CANDLES, and GLYCERINE. A Practical Manual of Modern Methods of Utilisation of Fats and Oils in the Manufacture of Soap and Candles, and of the recovery of Glycerine. By L. L. LAM BORN, Massachusetts Institute of Technology, M.Am.C.S. Medium 8vo, cloth. Fully Illustrated. 706 pages Net 3O/O THE SOAP INDUSTRY RAW MATERIALS BLEACHING AND PURIFICATION OF SOAP- STOCK THE CHEMICAL CHARACTERISTICS OF SOAP-STOCK AND THEIR BEHAVIOUR TOWARDS SAPONIFYING AGENTS MECHANICAL F.QUIVALENT OF THE SOAP FACTORY COLD PROCESS AND SEMI-BOILED SOAP GRAINED SOAP SETTLED ROSIN SOAP- MILLED SOAP-BASE FLOATING SOAP SHAVING SOAP MEDICATED SOAP ESSENTIAL OILS AND SOAP PERFUMERY MILLED SOAP CANDLES GLYCERINE EXAMINATION OF RAW MATERIALS AND FACTORY PRODUCTS. TRADES & MANUFACTURES, INDUSTRIAL ARTS, &*. 15 SOLUBILITIES OF INORGANIC AND ORGANIC SUB- STANCES. A Hand-book of the most Reliable Quantitative Solubility Determinations. Recalculated and Compiled by ATHERTON SEIDKLL, Ph.D., Chemist, Hygienic Laboratory, U.S. Public Health Service, Washington, D.C. Second Edition, Revised. Medium 8vo, cloth, 3/7 pages Net 1 2/6 TEA MACHINERY AND TEA FACTORIES. Describing the Mechanical Appliances required In the Cultivation and Preparation of Tea for the Market. By A. J. WAI.LIS-TAVLER, A.M.Inst.C.E. Medium 8vo, 468 pp. With 218 Illustrations Net 25/O " The subject of tea machinery Is now one of the first Interest to a large class of people, to whom we strongly commend the volume." Chambtr of Commerce JoUrnal. UPHOLSTERING: THE PRACTICAL UPHOLSTERER AND CUTTER-OUT. A Treatise on Upholstery in all its Branches, in- cluding the Stuffing and Covering of various Suites, &c., the Manufacture of all kinds of Bedding and Complete Directions for Planning Carpets, together with Instructions for the Cutting-out and Arrangement of Curtains, Valances, and Decorative Hangings, with Practical Illustrations, and Tabular Scale showing the Proportion for Cutting 130 Festoons of various sizes. By RICHARD BITMEAD, Prizeman at the London Exhibitions, Author of " Cabinet-Making " and " French Polishing and Enamelling.'" 112 pp., with Illustrations. Crown 8vo, cloth [/ust Published. 2/O WAGES TABLES. At 54, 52, 50, and 48 Hours per Week. Showing the Amounts of Wages from one quarter of an hour to sixty-four hours, in each case at Rates of Wages advancing by One Shilling from 45. to 555. per week. By iTHOs. CARBUTT, Accountant. Square crown, 8vo half-bound 6 O WATCH REPAIRING, CLEANING, AND ADJUSTING. A Practical Handbook dealing with the Materials and Tools Used, and the Methods of Repairing, Cleaning, Altering, and Adjusting all kinds of English and Foreign Watches, Repeaters, Chronographs, and Marine Chronometers. By F. J. GARRARD, Springer and Adjuster of Marine Chronometers and Deck Watches for the Admiralty. Second Edition. Revised. With over 200 Illustrations. Crown 8vo, cloth Net 4/6 WATCHMAKER'S HANDBOOK. Intended as a Workshop Companion for those engaged in Watchmaking and the Allied Mechanical Arts. Translated from the French of CLAUDIUS SAUNIER, and enlarged by JULIEN TRIPPLIN, F.R.A.S., and EDWARD RIGG, M.A., Assayer in the Royal Mint. Fourth Edition. Cr. 8vo, cloth 9/0 " Each part Is truly a treatise In Itself. The arrangement Is good and the language is clear and concise. It is an admirable guide for the young watchmaker." Engineering. WEIGHT CALCULATOR. Being a Series of Tables upon a New and Comprehensive Plan, exhibiting at one Reference the Exact Value of any Weight from i Ib. to 15 tons, at 300 Progressive Rates, from id. to i68s. per cwt., and containing 186,000 Direct Answers, which, with their Combinations, consisting of a single addition (mostly to be performed at sight), will afford an aggregate of 10,266,000 Answers; the whole being calculated and designed to ensure correctness and promote despatch. By HENRY HARBEN, Accountant. Sixth edition, carefully corrected. Royal 8vo, strongly half bound 1 5s. " A practical and useful work of reference for men of business generally." Ironmonger. "Of priceless value to business men." Sheffield tndtfeiidfut. WOOD ENGRAVING. A Practical and Easy Introduction to the Study of the Art. By W. N. BROWH. Crown 8vo, cloth. . 1/6 16 INDUSTRIAL AND USEFUL ARTS. HANDYBOOK8 FOR HANDICRAFTS. BY PAUL N. HASLUCK. Author of " Lathe Work," etc. Crown 8vo, 144 pp., price is. each. 13" These HANDYBOOKS have been written to supply information for WORKMEN, STUDENTS, and AMATEURS in the several Handicrafts, on the actual PRACTICE of the WORKSHOP, and are intended to convey in plain language TECHNICAL KNOW- LEDGE of the several CRAFTS. In describing the processes employed, and the manipu- lation of material, workshop terms are used ; workshop practice is fully explained ; and the text is freely illustrated with drawings oj modern tools, appliances, and processes. METAL TURNER'S HANDYBOOK. A Practical Manual for Workers at the Foot-Lathe. With 100 Illustrations . . . . 1 /O " The book displays thorough knowledge of the subject." Scotsman. WOOD TURNER'S HANDYBOOK. A Practical Manual for Workers at the Lathe. With ico Illustrations 1/0 " We recommend the book to young turners and amateurs." Mechanical World. WATCH JOBBER'S HANDYBOOK. A Practical Manual of Cleaning, Repairing, and Adjusting. With zoo Illustrations . .1/0 " All connected with the trade should acquire and study this \-iorY."Clerken-uiell Chronicle. PATTERN MAKER'S HANDYBOOK. A Practical Manual on the Construction of Patterns. With 100 Illustrations . . 1 /O "A most valuable, if not indispensable, manual for the pattern-maker." Knowledge. MECHANIC'S WORKSHOP HANDYBOOK. A Practical Manual on Mechanical Manipulation, embracing Information on various Handicraft Processes. With Useful Notes and Miscellaneous Memoranda. Comprising about 200 Subjects . . . . . . . . 1 /O " Should be found in every workshop, and in all technical Schools." Saturday Review. MODEL ENGINEER'S HANDYBOOK, A Practical Manual on the Construction of Model Steam Engines. With upwards of 100 Illus- trations 1/O "Mr. Hasluck has produced a very good little book." Builder. CLOCK JOBBER'S HANDYBOOK. A Practical Manual on Cleaning, Repairing, and Adjusting. With 100 Illustrations . . 1/O " It Is of inestimable service to those commencing the trade." Coventry Standard. CABINET WORKER'S HANDYBOOK. A Practical Manual on the Tools, Materials, Appliances, and Processes employed in Cabinet Work. With upwards of 100 Illustrations 1 /O "Amongst the most poetical guides for beginners in cabinet-work." Saturday Review. WOODWORKER'S HANDYBOOK. Embracing information on the Tools, Materials, Appliances and Processes Employed in Woodworking. With 104 Illustrations 1 /O " Written by a man who knows, not only how work ought to be done, but how to do It, nd how to convey his knowledge to others 'Engineering. "Mr. Hasluck writes admirably and gives complete Instructions." Engineer. " Mr. Hasluck combines the experience of a practical teacher with the manipulative skill and scientific knowledge of processes of the trained mechanician, and the manuals are marvels of what can be produced at a popular price." Schoolmaster. " Helpful to workmen of all ages and degrees of enperlence." Daily Chronicle, BRADBURY, AGNEW, & CO. LD., LONDON AND TONBR DGE. [483.18.11.12] WEALE'S SCIENTIFIC & TECHNICAL SERIES. MATHEMATICS, ARITHMETIC, &c. Geometry, Descriptive. J. F. HEATHER . . . 2/- Practical Plane Geometry. J. F. HEATHER. . . 2/- Analytical Geometry. J. HANN & J. R. YOUNG . . 2/- Geometry. Part I. (Euclid, Bks. I. III.) H. LAW 1/6 Part II. (Euclid, Books IV., V., VI., XI., XII.). H. LAW 1/6 Geometry, in i vol. (Euclid's Elements) . . . . 2/6 Plane Trigonometry. J. HANN . . . .1/6 Spherical Trigonometry. J. HANN . . . . i/- The above 2 vols. , bound together .... 2/6 Differential Calculus. W. S. B. WOOLHOUSE . . 1/6 Integral Calculus. H. Cox 1/6 Algebra. J. 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University of California ERN REGIONAL LIBRARY FACILITY rd Avenue, Los Angeles, CA 90024-1388 Return this material to the library was borrowed. WEALE'S SCIENTIFIC ! T gOO 418 174 BUILDING & ARCHITECTURE-con/rf. Architecture, Orders. W. H. LEEDS . . . . 1/6 Architecture, Styles. T. T. BURY . . . . 2/- The above 2 vola. , bound together . . . . 3/6 Architecture, Design. E. L. GARBKTT . . .2/6 The above 3 vola., bound together . . . . 6/- Architectural Modelling. T. A. RICHARDSON . . 1/6 Vitruvius' Architecture. J. GWILT . . . . 5/- Grecian Architecture. Lord ABERDEEN . . i/- The above 2 vola., bound together . . . . 6/- FINE ARTS. Dictionary of Painters. P. DARYL . . . . 2/6 Painting, Fine Art. T. J. GULLICK & J. TIMES . . 5/- Grammar of Colouring. G. FIELD & E. A. DAVIDSON 3/- Perspective. G. FYNE 2/- Glass Staining & Painting on Glass . . . . 2/6 Music. C. C. SPENCER 2/6 Pianoforte Instruction. C. C. SFENOER . . . 1/6 INDUSTRIAL & USEFUL ARTS. Cements, Pastes, Glues, & Gums. H. C. STANDAGE 2/- Clocks, Watches, and Bells. Lord GKIMTHOIU-E . 4/6 Goldsmith's Handbook. G. E. GEE . . 3/- Silversmith's Handbook. G. E. GEE , . . 3/- Goldsmith's & Silversmith's Handbook. G. E. GEK ;/- Hall-Marking of Jewellery. G. E. GEE . 3/~ Cabinet-Maker's Guide. R. BITMEAD . . .2/6 Practical Organ Building. W. E. DICKSON . . 2/6 Coach Building. J. W. BURGESS . . . .2/6 Brass Founder's Manual. W. GRAHAM . . . 2/- French Polishing and Enamelling. R. P,ITMEAD . 1/6 Upholstering and Cutting Out. R. BITMKAD . . 2/- House Decoration. J. W. FACF.Y. . . . . 5/- Letter-Painting Made Easy. J. G. BADENOCH . 1/6 Boot and Shoemaking. J. B. LEND . . . . 2/- Mechanical Dentistry. C. HUNTER . . . . 3/- Wood Engraving. W. N. BROWN 1/6 CROSBY LOCKWOOD & SON, 7, Stationers' Hall Court, E.G.