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 A TREATISE ON TEE 
 
 METALLUEGY OF IKON. 
 
A TREATISE ON THE 
 
 METALLUBGY OF IKON 
 
 CONTAINING OUTLINES OP 
 
 THE HISTOEY OF IEON MANUFACTUEE, 
 
 METHODS OF ASSAY AND ANALYSES OF IEON OEES, 
 
 PEOCESSES OF MANUFACTUEE OF IEON AND STEEL, 
 
 BY H. BAUEKMAN, F.G.S. 
 
 ASSOCIATE OF THE ROYAL SCHOOL OF MINES ; ASSOCIATE MEMBEE OF THE 
 INSTITUTION OF CIVIL ENGINEERS 
 
 SIXTH EDITION, REVISED AND ENLARGED 
 
 toith immmrxt0 Sit-oo 
 
 FROM DRAWINGS BY J. B. JORDAN 
 
 OF 
 
 UN 1 
 
 LONDON 
 
 CEOSBY LOCKWOOD AND SON 
 
 7, STATIONERS' HALL COURT, LUDGATE HILL 
 
 1890 
 [All rights reserved] 
 
1 Mir wiisse wie me's Else macht 
 Und wie' s im Sand zu Massie bacht , 
 Und wie me's druf in d' Schmidte bringt 
 Und d' Luppen unter'm Hammer zwingt." 
 
 IlEBEL. 
 
 GENERAL 
 
PREFACE. 
 
 THE importance of the subject has claimed for the 
 Metallurgy of Iron much careful scientific investi- 
 gation, both in this country and abroad ; but being 
 confined, for the most part, to large and expensive 
 works, or to the pages of scientific periodicals, it is 
 scarcely available for the technical education of the 
 great class to whom a general knowledge of the phy- 
 sical properties of the ores, and the latest and most 
 approved means of reducing them to a condition suited 
 for the purposes of the manufacturer, is desirable. 
 
 To supply this want is the chief object the author 
 has had in view in producing this volume, which he 
 believes will furnish much information that practical 
 workers of iron, students, and owners of iron mines 
 require, in a condensed and portable form. 
 
 A work of this nature, as a matter of course, must 
 
VI PREFAB. 
 
 in a great measure be a compilation from the larger 
 modern publications on the same subject. The author 
 acknowledges his obligations to the following published 
 abroad : 
 
 BAER. " Das Eisen," and the Swedish edition by Akerman. 
 
 KARSTEN. " Eisenhiittenkunde." 
 
 KERL. " Hiittenkunde," vol. iii. 2nd Edition. 
 
 KITTINGER. " Erfahmngen." 
 
 TUNNER. " Stabeisen und Stahlfabrikation." 
 
 "Report on International Exhibition, 1862," in the Leolen 
 
 Jahrbuch. 
 
 WAGNER'S " Jahresbericht fur technische Chemie." 
 " Berg und Hiittenmannische Zeitung of Freiberg." 
 " Oesterreichische Bergwerks Zeitung." 
 ANSIATTX AND MASSON. " Fabrication du Fer," &c. 
 DE VATHAIRE. " Etudes sur les Hauts Fourneaux." 
 GRUNER AND LAN. "Metallurgie du Fer en Angleterre," &c., 
 
 published in the Annales des Mines. 
 JORDAN. " Metallurgie du Fer au Pays de Siegen," published in 
 
 De Kuyper's Revue TJniversette. 
 
 He has also perused with considerable advantage, 
 especially in regard to our Iron Works Percy's 
 " Metallurgy of Iron and Steel/' Truran's " Iron 
 Manufacture of Great Britain," load's article " Iron " 
 in " lire's Dictionary," and articles on Iron Works in 
 ' Engineering." 
 
 The illustrations, drawn by Mr. J. B. Jordan, have 
 mostly been reduced from large-scale drawings, espe- 
 cially those published by the Technical Institute of 
 Berlin, under the title " Zeichnungen fiir die Hiitte." 
 
 LONDON, March, 1868. 
 
PEEFACE TO THE THIED EDITION. 
 
 IN preparing a new edition of this work, to be issued 
 in the series for which it was originally designed, 
 advantage has been taken of the opportunity to bring 
 it up to the present time by the insertion of notices of 
 the principal facts and processes in connection with 
 iron making, that have been made public during the 
 interval of four years that have elapsed since the work 
 was written. These additions have been introduced in 
 their proper places in the original text. Among them 
 will be found notices of the Siemens-Martin steel pro- 
 cess, probably the greatest advance made in iron- 
 metallurgy since Bessemer's great invention, as well as 
 the various plans proposed by Heaton, Ellerhausen, 
 and others. During the final revision of the sheets, 
 the Proceedings of the South Staffordshire Meeting of 
 the Iron and Steel Association were published, contain- 
 ing many papers which appear to be of great imme- 
 diate interest, and therefore notices of some of these 
 have been given as additional notes. 
 
PREFACE. 
 
 The present is the third edition, the second having 
 been issued for circulation in America, with the addi- 
 tion of a preface and appendix on the Siemens- Martin 
 process, by an eminent American ironmaster, the 
 Hon. Abram S. Hewitt, of New Jersey, who is well 
 known by his elaborate and exhaustive report on the 
 Metallurgy of iron as exhibited in Paris in 1867. 
 
 LONDON, September, 1871. 
 
 PEEFACE TO THE SIXTH EDITION. 
 
 THE progress in iron and steel manufacture during 
 the seven years that have elapsed since the last issue 
 of this volume having been mainly in the direction of 
 perfecting the appliances and working details of the 
 great processes introduced between 1858 and 1878, 
 it has not been found necessary to make any very 
 great alteration in the principal part of the text ; and 
 the additions required to bring the information up to 
 date have therefore been mostly placed as supplemental 
 notes at the end. These additions are about equivalent 
 to fifteen pages of the text. The statistical details have 
 been revised and brought up to the latest dates for 
 which returns are available. 
 
 LONDON, September, 1889. 
 
CONTENTS. 
 
 CHAPTER I. 
 
 PAGB 
 INTRODUCTORY AND HISTORICAL SKETCH . .... 1 
 
 CHAPTER II. 
 OUTLINE OF THE CHEMISTRY OF IRON . . . . . . 12 
 
 CHAPTER III. 
 COMPOSITION AND DISTRIBUTION OF IRON ORES .... 53 
 
 CHAPTER IV. 
 ASSAY AND ANALYSIS OF IRON ORES 103 
 
 CHAPTER V. 
 PREPARATION PP IRON ORES 122 
 
 CHAPTER VI. 
 ROASTING OR CALCINATION OF IRON ORES . . . . ,131 
 
 CHAPTER VII. 
 OF THE FLUXES USED IN IRON-SMELTING 145 
 
 CHAPTER VIII. 
 OF THE BLAST FURNACE AND ITS ACCESSORIES .... 160 
 
 CHAPTER IX. 
 CAPACITY AND PRODUCTION OF BLAST FURNACES , , 230 
 
CONTENTS. 
 
 < CHAPTER X. 
 
 OP THE CONSUMPTION OF FUEL AND DISTRIBUTION OP HEAT IN 
 
 THE BLAST FURNACE 258 
 
 CHAPTER XI. 
 VARIETIES AND COMPOSITION OP PIG IRON .... 272 
 
 CHAPTEB XII. 
 METHODS OF MAKING WROUGHT IRON DIRECTLY FROM THE ORE 279 
 
 CHAPTER XIII. 
 
 REFINING, OR CONVERSION OF GREY INTO WHITE CAST IRON . 289 
 
 CHAPTER XIV. 
 PRODUCTION OF WROUGHT IRON IN OPEN FIRES ... 303 
 
 CHAPTER XV. 
 REVERBERATORY FINERY OR PUDDLING PROCESS . .315 
 
 CHAPTER XVI. 
 FORGE AND MILL MACHINERY . .' . . * . 349 
 
 CHAPTER XVII. 
 
 /- BEHEATING AND WELDING 373 
 
 CHAPTER XVUI. 
 V METHODS OP PRODUCING STEEL . ., . . . .401 
 
 CHAPTER XIX. 
 
 ANALYSIS OP CAST AND WROUGHT IRON AND STEEL . . .480 
 CHAPTER XX. 
 
 MECHANICAL PROPERTIES AND TESTS OF MALLEABLE IRON AND 
 
 STEEL 496 
 
 SUPPLEMENTARY NOTES 608 
 
 INDEX 519 
 
LIST OF ILLUSTRATIONS. 
 
 1. Gjers' calcining kiln. 
 
 2. Swedish gas calcining kiln. 
 
 3. Styrian kiln for pyritic ores. 
 
 *. Charcoal blast furnace at Safvenas, vertical 
 
 5. Plan of charcoal blast furnace. 
 
 6. Vertical section of cupola blast furnace. Barrov-in-Furuess 
 
 7. Front view of hearth and dam of blast furnace. 
 
 8. Staffordshire blast furnace, section across hearth 
 
 9. Double-acting blowing engine, vertical section. 
 
 10. Hot blast stove, with U pipes. Dowlais. 
 
 11. Hot blast stove, with pistol pipes. Oberhausen. 
 
 12. Wasseralfingen stove at Neustadt. 
 
 13. Cowper's hot blast stove, vertical section. 
 
 14. Plan of a pair of Cowper's stoves. 
 
 15. Arrangement of bricks in Cowper's stove. 
 
 15* Whitwell's stove, as applied to a blast furnace at Consett. 
 
 16. Water twyer and blow pipe for hot blast. Bhonitz. 
 
 17. Furnace top, with cup-and-cone charger. South Wales. 
 
 18. Furnace top, with La ngen' s charger. Esehweiler. 
 18. Biittgenbach's blast furnace. 
 
 19. Rachette's blast furnace, vertical section 
 
 20. Eachette's blast furnace, plan through twyers. 
 
 21. Comparative sections of modern blast furnaces 
 
 22. Catalan finery fire. 
 
 23. Vertical section of refinery. 
 
 24. Plan of refinery. 
 
 25. Puddling furnace. 
 
 26. Carinthian gas puddling furnace. 
 
 27. Eastwood's mechanical puddler. 
 
 27#, 27b, 27c. Danks's rotatory puddling furnace. 
 
 28. 70-cwt. shingling helve. 
 
Xii LIST OF ILLJSTRATIOTSk, 
 
 FIG. 
 
 29. Thwaites and Carbutt's steam hammer. 
 
 30. Ramsbottom's duplex steam hammer. 
 
 31. Double lever squeezer. Dowlais. 
 
 32. Boiling mill. 
 
 33. Bail mill roughing rolls. 
 
 34. Rail mill finishing rolls. 
 
 35. Universal rolling mill. 
 
 36. Cropping shears. Dowlais. 
 
 37. Reheating furnace. 
 
 38. Sections of piles for finished iron. 
 
 39. Siemens' gas furnace, vertical section. 
 
 40. Siemens' furnace, plan of flues. 
 400, Ponsard's gas furnace. 
 
 40>. Ponsard's recuperator, transverse sectioa. 
 40c. Ponsard's recuperator, longitudinal section. 
 
 41. Steel converting furnace. 
 
 42. Steel melting furnace. 
 
 43. Siemens' steel melting furnace, vertical section. 
 
 44. Siemens' steel melting furnace, plan of flues. 
 
 45. Bessemer' s steel converting apparatus, detailed section. 
 
 46. Bessemer's apparatus, general view, with casting apparatus 
 46<z. Walker's 10-ton converter, side elevation. 
 
 46*. Walker's 10-ton converter, transverse section. 
 
 47. Siemens-Martin steel melting furnace. 
 
 48. Pernot's steel melting furnace, longitudinal section. 
 
 49. Pernot's steel melting furnace, transverse section. 
 
METALLURGY OF IKON 
 
 CHAPTER I. 
 
 INTRODUCTORY AND HISTORICAL SKETCH. 
 
 THE subject of iron- smelting is the largest and most 
 important in the whole domain of metallurgy, and, at 
 first sight, presents a remarkable contrast to all other 
 branches of the smelter's art. For in the case of most 
 of the other metals employed as such in the arts, we 
 have, as sources of supply, a numerous class of minerals 
 varying greatly in richness and composition, and sus- 
 ceptible of reduction to the metallic state by processes 
 also differing greatly among each other ; while, in the 
 case of iron, the few minerals that can be made useful 
 as ores are restricted within much narrower workable 
 limits, and form only one class of chemical compounds, 
 namely, oxides, whose reduction can be effected practi- 
 cally only by one agent that is, carbon or carbonic oxide. 
 But as a very high temperature is necessary to effect 
 the reduction, the metal almost always combines with a 
 greater or less proportion of the reducing agent, as well 
 as of other elementary substances, such as silicon, 
 sulphur, and phosphorus, thfat may be present either in 
 the ore, the fuel, or the flux, so that the ultimate 
 result is never a pure metal, but a series of compounds, 
 
2 METALLURGY OF IRON. 
 
 varying in properties from great hardness to perfect 
 malleability, and from ready fusibility to almost abso- 
 lute infusibility. 
 
 Practically speaking, absolutely pure iron may be 
 said to be of no commercial value. But, on the 
 other hand, extraordinarily small traces of foreign 
 elements exert a very marked influence on the metal, 
 and it is precisely these small and, in many cases, un- 
 noticed differences of composition, that render so many 
 points in the chemistry and practical working of iron 
 obscure and difficult to be understood. When it is 
 considered that the investigation of such problems calls 
 for researches involving the utmost refinements of 
 analytical chemistry, it is not remarkable that contra- 
 dictory statements and opinions still abound on many 
 points of the chemistry of iron-making. 
 
 The mechanical considerations involved in this sub- 
 ject are almost as important as the chemical; for, 
 unlike the smelter of other metals, who is able by fusion 
 alone to bring his finished product to a merchantable 
 state, the iron smelter has to deal with pasty infusible 
 masses, which require to be compacted and moulded by 
 pressure by powerful machines, such as hammers, 
 presses, rollers, &c., before they can be made available 
 for consumption. 
 
 In view, therefore, of the great magnitude of the 
 subject, it may be as well to state, at starting, that the 
 treatise now placed in the reader's hands is devised to 
 furnish such information connected with the metallurgy 
 of iron as may be necessary for the elucidation of the 
 general principles upon which the processes used in the 
 reduction of iron from its ores are based. While, there- 
 fore, referring the student for the detailed discussion of 
 
INTRODUCTORY AND HISTORICAL SKETCH. d 
 
 the various points to the larger works on the same sub- 
 ject, such, for example, as the elaborate volume pub- 
 lished by Percy, in this country, and those of Karsten. 
 Flachat, Yalerius, Julien, Tunner, and others on the 
 Continent, we shall proceed to notice in as succinct 
 a manner as possible, the principal facts and opinions 
 current in the modern practice of iron- smelting under 
 the following general headings : - 
 
 1. Outline of the chemistry of iron from the metallur- 
 gical point of view, noticing only such compounds as 
 immediately interest the smelter. 
 
 2. Composition modes of occurrence and distribution 
 of the ores of iron. 
 
 3. Methods of assaying, mixing, and fluxing ores. 
 
 4. Description of processes whereby the ores are 
 reduced to the metallic state. 
 
 Before entering upon the consideration of the above 
 subjects, it will be convenient to state broadly the 
 nature of the finished products of the iron smelter's 
 labour, and to glance rapidly at the historical part of 
 the subject. 
 
 Of the Products of Iron Smelting Cast Iron Malleable 
 Iron Steel. 
 
 Iron is employed in the arts under three several 
 states, whose variable properties are mainly due to dif- 
 ferences in the quantity of carbon present, and in a 
 lesser degree to that of other foreign matters. When 
 alloyed with a maximum of the latter element, an 
 amount which in ordinary smelting does not exceed 
 6 per cent., or fall below 2 per cent., the substance 
 obtained is known as cast iron or pig metal This 
 
 B2 
 
4 METALLURGY OP IRON. 
 
 is a hard and comparatively brittle substance, which 
 can be readily fused at a high temperature, and is 
 susceptible of being moulded into solid forms by cast- 
 ing, but also in most modern iron works forms an 
 intermediate product in the manufacture of the other 
 classes. According as the metal may be most adapted 
 for founders' or forge-masters' use, it is distinguished 
 as forge or foundry pig. 
 
 Wrought or Malleable Iron. This, the nearest approach 
 to the chemically pure metal that can be obtained on 
 the large scale, may be almost absolutely free from 
 carbon, and never contains more than 0*25 per cent. 
 It is a soft, malleable, and extremely tenacious sub- 
 stance, infusible, except at the extreme temperatures 
 obtainable in furnaces of special construction, but 
 capable of being agglomerated by pressure, when at a 
 white heat, to a compact state by the process of welding. 
 When heated and suddenly cooled, it retains its soft* 
 ness. It may be produced either directly from the ore 
 or by the conversion of pig iron. The varieties of 
 malleable iron are distinguished by many different 
 names, but these have reference rather to form and 
 destination than to differences of composition. 
 
 Steel. Those varieties of iron in which the amount of 
 carbon is above the maximum of malleable, and below 
 the minimum of cast metal, are known as steel. The 
 distinguishing property of this class of products is the 
 power of being hardened or softened at pleasure, by 
 sudden or rapid cooling, by the process known as tem- 
 pering. Being intermediate in position between wrought 
 and cast iron, steel is both fusible and malleable, but 
 requires a higher temperature for fusion than the latter, 
 and greater compressing power, owin^ to its lower 
 
INTRODUCTORY AND HISTORICAL SKETCH. 5 
 
 welding temperature, than the former. Those varieties 
 that are richest in carbon are the hardest and most fusible, 
 and are known as strong steels, while those that are 
 nearer malleable iron in composition are distinguished 
 as mild steek or steely irons. Steel may be obtained 
 either direct from the ore at one operation, or indirectly 
 by a variety of processes of greater or less complexity 
 from either cast or wrought iron. 
 
 Outline of the Progress of Iron Manufacture. The 
 history of the production of iron is probably almost 
 co-extensive with that of the human race ; at least, it goes 
 back far beyond the periods of authentic history. 
 According to the Pentateuch (Gen. iv. 22) the dis- 
 covery of iron is attributed to Tubal Cain, who is said 
 to have been sixth in descent from Adam. Pagan 
 tradition assigns the discovery to Vulcan, placing it 
 about the time of Deucalion's deluge. / There can be 
 little doubt that the discovery was made at a very 
 early period, as the production of small masses of 
 malleable iron is one of the simplest of all metallur- 
 gical operations, requiring only a small furnace without 
 blowing apparatus, such as can be made by digging 
 a hole in the side of any bank exposed to the prevailing 
 wind, a supply of easily reducible ore, ancl charcoal for 
 fuel. Such processes) as these have been described as 
 in use in Africa by Mungo Park, and are still employed 
 in Birmah ; and probably something of the same kind 
 is indicated by the tradition which ascribes the discovery 
 of iron in Scythia to the effects of forest fires in dis- 
 tricts containing iron ores, when portions of the reduced 
 metal are said to have been found among the ashes of 
 the burnt trees. 
 
 It may have been, however, that the masses of iron 
 
O METALLURGY OF IRON. 
 
 referred to were meteorites, whose existence was first 
 made apparent by the clearing of the ground. 
 
 Homer refers several times to iron and steel. Thus 
 in the twenty-third Iliad, Achilles, at the funeral games 
 of Patroclus, gives a disc of iron as the prize ; and 
 in the ninth Odyssey, the hissing of the burning stake 
 that Ulysses plunges into the eye of Polyphemus is 
 compared to the noise produced when steel is hardened 
 by quenching it with water when at a red heat. 
 
 Probably the first important improvement in the 
 manufacture was the introduction of the artificial blast, 
 which is of great antiquity. In Egyptian sculptures 
 of the reign of Thothmes III. (1505 B.C.) smiths are repre- 
 sented working at a forge, which is provided with two 
 simple leather bellows, worked by the pressure of men's 
 feet for the exhaust, and inflated by strings pulled by 
 hand, in a manner exactly similar to that still employed 
 in Birmah. 
 
 Aristotle (B.C. 384-322) describes the process of making 
 cast steel used in India, which is still produced under 
 the name of wootz ; and also the manner in which the 
 Chalybes of the Euxine procured iron. Pliny (A.D. 23- 
 79) mentions the great masses of iron ore still worked 
 in Elba, Styria, and Spain, and describes the methods 
 of making iron and steel, especially remarking that the 
 quality of the latter depended upon the water used in 
 quenching, and that small tools were tempered in oil. 
 (" Natural History/' bk. xxxiv. chap. 41.) 
 
 Diodorus (B.C. 60-40), in describing the iron works of 
 Elba, states the ore was reduced to small pieces and 
 heated in furnaces ; the charge, when properly softened, 
 was removed and divided into small masses, which had a 
 spongy appearance (blooms), and were exported to the 
 main land of Italy for conversion into tools. 
 
INTRODUCTORY AND HISTORICAL SKETCH. i 
 
 Galen (A.D. 131) remarks that knives made of Indian 
 iron (steel) were remarkable for their strength and 
 hardness, but were often so brittle that the cutting 
 edge splintered off, owing to their having been ira 
 properly tempered. 
 
 /According to Franquoy, bellows with valves were in- 
 troduced by the Romans into Gaul during the fourth 
 century A.D. These, although single acting and made 
 of leather, were a considerable advance upon the savage 
 form, which required strings for their inflation. The 
 wooden double bellows, which are still in use in some 
 parts of the Continent, may be regarded as the pre^ 
 cursors of the cylinder blowing engine, and were intrc= 
 duced into the Harz about 1620, either from Franconia 
 or Thuringia. 
 
 During the middle ages the great improvement 
 consisted in the gradually increasing height of the 
 furnace, consequent on the use of ores of an infusible 
 and difficultly reducible character. This necessitated 
 a special means of withdrawing the reduced mass 
 of iron (lump or bloom), which was effected through a 
 lateral opening in the hearth, or lower part of the 
 furnace, instead of being lifted out from above, as 
 was done with the ordinary open fire. With the 
 increased length of the operation, the reduced metal 
 being left for a considerable time in contact with the 
 fuel, facility was given for a greater absorption of 
 carbon, resulting in the formation of a larger quan- 
 tity of molten pig iron, which was run out with the 
 slag, than was the case with the open fires. The 
 increased height of the furnace is well seen in Agricola 
 ("De Re Metallica," lib. xii. edit. 1546), who describes 
 two different methods of iron-working as common in 
 
8 METALLURGY OF IRON. 
 
 his time. The text is not very clear, but the engravings 
 represent, in the first case, an ordinary bloomery, in 
 which malleable iron is produced directly from the ore, 
 together with a certain quantity of hard or pig iron ; 
 while, in the second method described as in use with 
 refractory ores, the furnace has a shaft of such a height 
 that the furnace-man requires to ascend a short flight 
 of steps to reach the throat, or charging-place. It is 
 surprising that this author makes no mention of 
 foundry work ; but as he states that the " hard iron " 
 of the bloomery was useful for stamp heads, he was 
 probably acquainted with the use of iron castings, but 
 not with their mode of manufacture. The omission 
 may also be accounted for by supposing that no 
 foundries existed in Saxony, to which country most 
 of Ao'ricola's descriptions refer, until some time after 
 their establishment in the Rhenish and Low Countries. 
 The subject of iron-founding is noticed by Lazurus 
 Ercker in his " Probierbuch," published in 1574. Kar- 
 sten supposed that the Stuckofen, or high bloomery 
 furnace above referred to, was of Eastern origin, and 
 was first introduced into Styria, travelling thence 
 westward to Burgundy and Alsace, subsequently re- 
 turning eastward into Bohemia and Saxony ; and that 
 the later forms of Blauofen and high furnace (the 
 prototypes of the modern blast furnace) were invented 
 in the Netherlands. The first indications of the latter 
 are found in Lorraine and in the Grerman. Khineland. 
 Franquoy, who seeks with patriotic zeal to establish 
 the priority of invention of the blast furnace to the 
 Liege district, states that according to documentary 
 evidence the hauts fourneaux at Yennes and Grivegnea 
 in that country were established before A.D. 1400, and 
 
INTRODUCTORY AND HISTORICAL SKETCH. 9 
 
 also that the furnace at Marche les Dames was built by 
 William, Count of Namur, A.D. 1340. Karsten, on the 
 other hand, states that although the knowledge of 
 pig iron dates from time immemorial, its use and 
 systematic production for foundry purposes cannot 
 be traced back with certainty to an earlier period 
 than the end of the fifteenth century. 
 
 In England, the blast furnace was probably in use at 
 a very early period, as we have evidence, according to 
 Lower, of ornamental castings being made in Sussex 
 some time in the fourteenth century. The principal 
 seats of the iron trade at that period in England were 
 in the great forests of Sussex, Gloucestershire, and South 
 Wales, where, under the older forms of bloomeries, iron 
 works had existed since the days of the Romans. The 
 gradual diminution of the forests of Sussex under the 
 demands of the furnace, a process of destruction which 
 may be seen going on at the present time with increased 
 rapidity in Sweden, North America, and other countries 
 producing charcoal iron, led to the passing of a stringent 
 act in 1584 (27th Elizabeth) forbidding the further 
 erection of iron works in the Weald of Sussex except 
 under certain limitations. With the commencement of 
 the seventeenth century came the first attempts at 
 smelting with mineral fuel, the pioneer of this parti- 
 cular improvement being Dud Dudley, who in 1619 
 produced both pig and wrought iron with coal in Wor- 
 cestershire ; but the scheme was unsuccessful, owing to 
 the opposition of the charcoal iron masters, so that 
 after trials in several localities extending over upwards 
 of thirty years, all of which ended unfortunately, the 
 inventor finally abandoned the subject. A similar trial 
 was made in Hainault by Octavius Strada, a native 
 B 3 
 
10 METALLURGY OF IRON. 
 
 of Bohemia, in 1625, who obtained a monopoly of the 
 invention for twenty-five years, but it led to no prac- 
 tical results. It was not till more than a century later, 
 namely, in 1735, that the problem of smelting with coal 
 was successfully solved by Abraham Darby, of Cole- 
 brookdale, who was the first to use coke in the blast 
 furnace, an improvement which spread rapidly into all 
 other iron-producing districts situated on or near the 
 coal measures. The last furnace in the Weald of 
 Sussex, at Ashburnham, was blown out in 1829, and 
 there are now only two or three scattered representa- 
 tives of the ancient charcoal furnaces remaining in 
 the whole of the United Kingdom. The century fol- 
 lowing the success of Abraham Darby is marked by 
 the introduction of the two great inventions which 
 especially distinguish the modern period of iron mariii- 
 facture ; that is, the substitution of the reverberatory 
 furnace for the open fire in the forge, and the use 
 of heated air in the blast furnace. The former change 
 effected by the puddling process, invented by Cort in 
 1784, has almost superseded all the older methods of 
 making malleable iron ; and the latter, due to Neilson 
 and Condie, and first used at the Clyde Iron Works in 
 1828, has greatly increased the productive power of the 
 blast furnace, with a diminution in the consumption of 
 fuel. 
 
 Since the introduction of the hot blast, the chief 
 improvement in the blast furnace is that of intercepting 
 the gases, which were formerly allowed to burn to 
 waste at the throat, and leading them off by distri- 
 buting pipes, to be usefully employed as fuel under 
 steam boilers, hot blast stoves, &c. This was patented 
 in France in 1811 by Aubertot, the gases being 
 
INTRODUCTORY AND HISTORICAL SKETCH. 11 
 
 employed for heating steel furnaces. In 1832 the 
 waste gases were used for heating the blast at Wasser- 
 alfingen, in Bavaria, and a similar apparatus was first 
 erected in this country in 1848 by J. P. Budd, at 
 Ystalyfera, in Glamorganshire, since which time various 
 modifications of the same plan have been adopted to a 
 considerable extent, especially in those furnaces that 
 are obliged to draw their fuel from a distance. 
 
 Within the last lew years, the chief inventions and 
 improvements have been in steel manufacture, and 
 many new processes have been introduced. Prominent 
 among these is that named after its inventor, Henry 
 Bessemer, which, since its introduction in 1858, has 
 effected important services by the production of a 
 material admirably adapted for railway and other 
 structural purposes in the place of wrought iron^XThe 
 same process as modified by Thomas and Gilchrist in 
 1878 has rendered the more ordinary kinds of iron ore 
 available for steel making, which were, formerly rejected 
 as. containing too much phosphoru^r The open hearth 
 process of steel making, due to the late Sir William 
 Siemens, has supplied ship builders and engineers with 
 n soft iron of a uniformity of composition unattainable 
 in the older forge processes, and steel that may be cast 
 almost as readily as cast iron. 
 
 With the exception of the Weald of Sussex, very little 
 change has taken place in the position of our principal 
 iron- working centres from the earliest time down to the 
 present day. Since the great expansion of railways 
 several new and important localities have been brought 
 into work, the ores being carried to the fuel or the 
 reverse, according as might be most advantageous. In 
 this way the great northern coal field of England, which 
 
12 METALLURGY OF IRON. 
 
 is almost absolutely without ironstone, gives rise to the 
 largest production in the kingdom by feeding the Cleve- 
 land district with coal and coke, and drawing iron- 
 stone for its own fttrnaces in return. The prevalence 
 of cheap ores in the oolitic districts has brought the 
 blast furnace to within fifty miles of London in North- 
 amptonshire, and the pastoral districts of Wiltshire 
 have been invaded by the same visitor. It need not, 
 therefore, be a matter of much surprise if at some 
 future period the Wealden furnaces were to be re-lighted, 
 as they could be easily supplied with fuel from the 
 western coal fields should the supply of ore be sufficient 
 to warrant the attempt, especially as on the opposite 
 coast of France large furnaces have been established 
 for smelting ores out of the same formation, and which 
 are supplied with fuel from England. 
 
 CHAPTER II 
 
 0-UTLINE OF THE CHEMISTRY OF IRON. 
 
 THE chief chemical points involved in the metallurgy 
 of iron will next be briefly noticed under this head, 
 in the order adopted equally by Karsten in his classical 
 " Eisenhiittenkunde," and also by Percy, commencing 
 with the pure metal, and proceeding to notice the prin- 
 cipal compounds with other elements, metallic and non- 
 metallic, that are of importance from a metallurgical 
 point of view. 
 
 Metallic Iron. This may be obtained in a chemically 
 pure condition by reducing peroxide of iron by hydro- 
 
OUTLINE OF THE CHEMISTRY OF IRON. 13 
 
 gen at a red heat, or by re-melting the purest varieties 
 of malleable iron with an oxidising flux, in order to 
 remove the last traces of combined carbon. It may 
 also be deposited by electrolysis from a solution of pro- 
 tochloride of iron, in the form of brilliant malleable 
 films, a process that has been employed by engravers 
 to protect the face of engraved copper plates from undue 
 wear during printing, and is known as acicracjc, or steel 
 facing. It does not appear to be quite certain, how- 
 ever, from the contradictory statements made by differ- 
 ent observers, that electro-deposited iron so obtained 
 is absolutely free from nitrogen. 
 
 The physical properties of the metal vary very con- 
 siderably, according to the means adopted for its pro- 
 duction. When obtained by reducing peroxide of iron 
 by hydrogen at the lowest possible temperature at 
 which the change can be effected (according to Magnus 
 between 600 and 700 F.), it forms a dark grey 
 powder, which combines energetically with oxygen, 
 taking fire spontaneously when slightly heated and 
 thrown into the air. When, however, the reduction 
 takes place at a higher temperature, the metallic powder 
 agglutinates to a sponge of a filamentous texture, a 
 silvery grey colour, and metallic lustre, which is no 
 longer pyrophoric. 
 
 Larger and more compact masses may be obtained by 
 removing the last traces of carbon and other foreign 
 substances from the purest commercial wrought iron 
 in the following manner : A small quantity, from 300 
 to 500 grains, of good wrought iron, such as pianoforte 
 wire or Russian black plate, cut up into small pieces, 
 and either rusted by exposure to steam or mixed with 
 about 20 per cent, of pure peroxide of iron, is to be melted 
 
14 METALLURGY OF IRON. 
 
 under glass free from, metallic oxides, in a refractory 
 crucible, at a strong white heat, the operation requiring 
 about an hour's full heat of a good wind furnace. The 
 small quantity of carbon present in the metal is ex- 
 pended in reducing a portion of the sesquioxide, the 
 remainder passing into the slag ; the result being a 
 brilliant well-melted button of metal, which exhibits a 
 decidedly crystalline structure, similar to that observed 
 in meteorites when treated with an etching liquor, and 
 is somewhat softer, but less tenacious, than the iron 
 originally employed. Another method of obtaining 
 iron absolutely pure, or nearly so, has been recently 
 adopted by Matthiessen in an experimental research 
 into the composition of cast iron. A mixture of proto- 
 sulphates of iron and soda, in nearly equal proportions, 
 are fused in a platinum crucible until the evolution of 
 sulphurous acid gas ceases. The iron is left as a finely 
 crystalline peroxide, and may be separated from the 
 fused mass by treatment with water, the last traces of 
 sulphuric acid being removed by long and careful 
 washing. The peroxide so obtained is reduced to the 
 spongy state by hydrogen, and the spongy metal, after 
 being consolidated by pressure in a steel mould, is 
 melted in a crucible, made of caustic lime, before the 
 flame of the oxyhydrogen blow-pipe. The metal pro- 
 duced by this method is said to be free from phosphorus, 
 silicon, and calcium, but contains a minute trace of 
 sulphur. 
 
 The electro-deposition of iron has recently been 
 effected, on a comparatively large scale, by Jacobi. 
 Instead of the protochloride, a solution of the double 
 sulphate of protoxide of iron and magnesia is used, care 
 being taken to keep the solution as nearly neutral as 
 
OUTLINE OF THE CHEMISTRY OF IRON. 15 
 
 possible. The strength of the electric current must be 
 regulated so that very little hydrogen is evolved. 
 
 Electro-deposited iron obtained by this process is 
 exceedingly hard and somewhat brittle, but, on anneal- 
 ing, especially in hydrogen, it becomes malleable, soft, 
 and silvery-white. The specific gravity is 7*675 in the 
 state of original deposition, which is increased by an- 
 nealing to 7-811, in the same manner as ordinary 
 malleable iron or steel. Like palladium, it possesses 
 the power of dissolving or occluding hydrogen, though 
 to a considerably smaller extent. By heating the de- 
 posited iron in vacuo it gives up from seventeen to 
 twenty times its volume of hydrogen. 
 
 According to Lenz (Pogg. Ann 1870, vol. v., p. 242) 
 the properties of electro- deposited iron vary very con- 
 siderably according to its subsequent treatment. When 
 the iron is deposited by a weak current from a solution 
 containing no free acid, it is of a fine granular texture, 
 not showing a crystalline structure under the micro- 
 scope, and exceedingly hard, so that it can scarcely 
 be touched by the file. The hardness is given, accord- 
 ing to the mineralogical scale, as 5 '5, or intermediate 
 between that of apatite and felspar. It is also re- 
 markably brittle ; thin plates can ba rubbed to powder 
 between the fingers, and even a piece iV of an inch in 
 thickness was easily broken. By annealing over a 
 cnarcoai hre, the hardness is reduced to 4'5, i.e., the 
 iron scratches fluor-spur, but not apatite ; and the brit- 
 tleness is replaced by extreme softness and ductility ; 
 the thin plates, that crumbled when handled before 
 annealing, becoming so tenacious that they may be 
 repeatedly folded backwards and forwards even oftener 
 than a sheet of paper without breaking. When 
 
16 METALLURGY OF IRON. 
 
 heated in vacuo, electro-deposited iron changes colour, 
 and becomes nearly as white as hammered platinum ; 
 at the same time a considerable quantity of the 
 gases, absorbed during the reduction, are given off. The 
 proportion between the volume of these gases, which 
 consist chiefly of hydrogen, and that of the iron plate 
 depends chiefly upon the thickness of the latter; the 
 absorptive power diminishing as the thickness increases. 
 In one instance a very thin film was found to contain 
 185 times its volume of occluded gases. The iron 
 which has been deprived of its gases by heat is ex- 
 tremely susceptible to oxidation, and rusts rapidly 
 when kept in water free from air ; at the same time 
 hydrogen is reabsorbed to a small extent, so that the 
 oxidation is due to the decomposition of water by the 
 iron at ordinary temperatures. 
 
 Action of Seat. The melting-point of pure, or 
 even ordinary, malleable iron has not been deter- 
 mined with certainty. According to Pouillet it lies 
 between 1,500 and 1,600 centigrade, while Scheerer 
 gives it as 2,100 of the same scale. The linear 
 dilatation by heat is T*IT between and 100, and irlr 
 between and 300 0.* 
 
 Magnetism. Pure iron is susceptible of being mag- 
 netised to a much higher degree than steel, but unlike 
 the latter metal, it does not retain its magnetism when 
 the exciting cause is removed. The following deter- 
 minations of the proportional magnetism of different 
 compounds of iron are by Pliicker (Miiller's " Physik," 
 vol. ii. p. 402) : 
 
 * In future, except where otherwise stated, the temperatures will be 
 expressed in centigrade degrees. 
 
OUTLINE OF THE CHEMISTRY OF IRON. 17 
 
 Magnetic power. Metallic iron 100,000 
 
 Magnetic oxide .... 40,227 
 
 Native peroxide .... 761 
 
 ,, Precipitated peroxide . . 714 
 
 Solution, nitrate of peroxide 410 
 
 ,, ,, protochloride . . 490 
 
 ,, Hydrated peroxide . . . 296 
 
 Specific Heat. 0-11379 according to Eegnault. The 
 conductivity for heat is 119, and that for electricity 
 122'5 in soft and 121*2 in hard drawn wire, silver at 
 being taken as = 1,000 (Despretz). The electric 
 resistance is 5'88 times that of a copper conductor of 
 equal section. 
 
 The crystalline forms of iron are most probably to 
 be referred to the cubical system, although there is 
 some difference of opinion on this subject. Fuchs sup- 
 posed them to be in part rhombohedral, and that the 
 metal is dimorphous ; the balance of opinion is, how- 
 ever, in favour of the former view. The observed 
 forms are the cube, octahedron, and tetrahedron. Ac- 
 cording to Peligot, brilliant cubical crystals are occa- 
 sionally obtained when protochloride of iron is reduced 
 by hydrogen in a porcelain tube at a red heat. The 
 symbol is Fe in dyad or ferrous combinations, and 3?e 
 when hexad or ferric. The equivalent is 28, and the 
 Atomic weight 56. 
 
 Passivity of Iron. When a bright iron wire is im- 
 mersed in fuming nitric acid, containing a certain 
 amount of nitrous acid, it becomes passive ; that is, it 
 is not dissolved, even if placed in acid of the ordinary 
 strength, as long as no great increase of temperature 
 takes place. If, however, the temperature be raised, or 
 the metal be touched by a copper wire, it is immediately 
 attacked and dissolved. 
 
18 METALLURGY OF IRON. 
 
 If the experiment be tried with ordinary nitric acid, 
 a violent action is set up, and goes on until the wire is 
 completely dissolved ; but by removing it from the 
 liquid, and keeping it out until the adherent film of 
 acid has become saturated, the face of the metal becomes 
 of a dead white hue, and on re-immersion is found to 
 have assumed the passive condition, which it retains 
 until it is rubbed or polished. Steel wire, when similarly 
 treated, gives rise to a violent ebullition for about twenty 
 seconds, which suddenly ceases, and no further action 
 takes place. This behaviour is characteristic of al] 
 varieties of steel, however they may have been pro- 
 duced, and is a good method of distinguishing them 
 from soft iron, which is rapidly dissolved under these 
 conditions. By placing a bar of steel and another of 
 iron in the same acid, and bringing their ends which 
 project beyond the liquid into contact, the latter is 
 rendered passive, and remains so as long as the 
 temperature of the liquid is not raised above 40. 
 Steel which has been rendered passive in the cold may 
 be digested for an indefinite period in boiling nitric 
 acid, without undergoing any perceptible alteration. 
 
 The cause of this peculiar property is not well made 
 out ; it is, however, supposed that it may be due to the 
 formation of a very thin, but closely adherent film of 
 oxide, which in some way acts like a varnish and pro- 
 tects the metal below from any further alteration. 
 
 According to the recent researches of Ordway, the 
 maximum temperature at which passivity may be in- 
 duced in malleable iron varies with the strength of the 
 acid used. 
 
 Thus, with acid of specific gravity 1*38, iron is 
 passive at 31, but is attacked at 32; with 1-42 
 
OUTLINE OF THE CHEMISTRY OF IRON. 
 
 19 
 
 it is passive at 55, but is attacked at 56. "With 
 red fuming acid of specific gravity 1*42 iron is passive 
 at 82, but is attacked at 83. 
 
 Compounds of Iron and Oxygen. Iron unites with 
 oxygen in many different proportions, of which com- 
 pounds three are simple oxides ; but these combine 
 among themselves into more complex bodies. The 
 following are the simple forms, with their symbols, 
 atomic weights, and percentage compositions : 
 
 
 Symbols. 
 
 Atomic Weight. 
 
 Percentage Composition. 
 
 Protoxide, orfemms 
 oxide .... 
 Peroxide, sesqui-, or 
 1 ferric oxide . . 
 Ferric acid . . . 
 
 FeO. 
 
 Fe20 3 
 Fe0 3 
 
 Iron. 
 56 
 
 112 
 56 
 
 Oxygen. 
 16 
 
 38 
 48 
 
 Iron. 
 
 777 
 
 70-0 
 53-9 
 
 Oxygen. 
 22-2 
 
 30-0 1 
 46-1 x 
 
 The first and last of the above compounds are very 
 unstable substances, and have never been isolated, or 
 at any rate with sufficient certainty to allow of a deter- 
 mination of their physical aad chemical characters. The 
 peroxide, on the other hand, occurs abundantly in a 
 nearly pure state, forming the hard and brilliant 
 mineral known as hematite or iron glance. A lower 
 oxide of the composition, Fe 4 0, is said to be formed 
 when iron is burnt in oxygen, but this is doubtful. 
 
 Protoxide of Iron. Although it has been generally 
 stated that this oxide is too unstable a substance to be 
 able to exist in an isolated state, yet according to Debray 
 it is formed when mixtures of steam and hydrogen are 
 passed over sesquioxide of iron at a red heat, provided 
 that the proportion of the two gases to each other be 
 not less than equal equivalents, or more than three 
 
20 METALLURGY OF IRON. 
 
 of hydrogen to one of steam. With a greater propor- 
 tion of hydrogen metallic iron is formed. The oxide so 
 produced is said to be a non-magnetic black powder, 
 which may be burnt in air, forming magnetic oxide. 
 There are several known combinations of proto- and 
 peroxide of iron. The most basic, and therefore the 
 nearest approach to the pure protoxide, is found in 
 the inner portion of the black magnetic scale which 
 forms upon the surface of bar iron when heated to red- 
 ness with access of air. The scale so formed, when 
 of any thickness, is found to vary in comDOsition 
 from a nearly pure sesquioxide externally, to a sub- 
 stance which, although probably not a definite chemi- 
 cal compound, may be represented by the formula 
 6 FeO -h Fe 2 3 on the inside in contact with the 
 metal. When the two oxides are combined in equal 
 equivalents, a substance is formed which occurs largely 
 in nature as a definite mineral, known as magnetite or 
 magnetic iron ore, which crystallises in the cubical 
 system, and is, as its name implies, distinguished for 
 its magnetic properties. It is a member of the group 
 of minerals known as the Spinel group, all of which 
 crystallise in the same form, and have the same general 
 formula of RO -f R 2 3 ; or, as it is sometimes con- 
 tracted, R 3 4 ; thus FeO -f Fe 2 3 = Fe 3 4 . 
 
 Hydrated Protoxide of Iron may be produced by pre- 
 cipitation from the solution of a protosalt by the addi- 
 tion of potash or soda. It is a white flocculent powder, 
 which almost immediately becomes green from the 
 formation of hydrated magnetic oxide. When freshly 
 prepared, however, the protoxide is soluble in 150,000 
 times its own weight of water, to which it gives an alkaline 
 reaction It is a strong base, and unites readily with 
 
OUTLINE OF THE CHEMISTRY 0V IRON. 21 
 
 acids to form protosalts, which are mostly unstable 
 compounds unless kept out of reach of the air, as they 
 absorb oxygen with greater or less facility, and pass 
 into the state of basic salts of the peroxide. The most 
 important of these salts occurring in an anhydrous state 
 is the carbonate, FeO. CO 2 , which is found abundantly 
 in nature crystallised in a pure state as spathic iron 
 ore, or siderite, in isomorphous combination with the 
 carbonates of lime and magnesia as brown spar and 
 pearl spar, or in an amorphous state associated with a 
 greater or less proportion of carbonate of lime and clay, 
 forming concretionary nodules, or septaria, of clay iron- 
 stones and cement- stones in argillaceous strata of 
 different geological periods. 
 
 Protocarbonate of iron is sensibly soluble in water 
 containing free carbonic acid, forming a bicarbonate, 
 which is retained as such as long as the solution is pro- 
 tected from the air, but is rapidly altered by absorption 
 of oxygen into hydrated peroxide by exposure, as, for 
 instance, when waters that hold iron in solution are 
 exposed in ponds or swamps. This property has a 
 most important bearing on the origin of ores, as it 
 furnishes a means by which large masses of mineral 
 may be elaborated from rocks comparatively poor in 
 iron. 
 
 When heated to redness with access of air, proto- 
 carbonate of iron is decomposed, giving rise to the 
 magnetic oxide, half of the acid being reduced to car- 
 bonic oxide in order to supply the necessary oxygen : 
 thus 
 
 2 FeO. CO 2 - (FeO + Fe 2 3 ) + CO + CO 3 . 
 \Yhen iron-filings diffused through water which has 
 
22 METALLURGY OF IRON. 
 
 been thoroughly deprived of air are subjected to the 
 action of carbonic acid gas, the water is partially decom- 
 posed, hydrogen is evolved, and protocarbonate of iron 
 is formed, which remains in solution until the excess of 
 acid is removed. 
 
 Peroxide or Sesquioxide of Iron (Fe 2 3 ). This oxide 
 is largely met with in nature, both anhydrous, as 
 hematite, iron glance, or red iron ore, a mineral having, 
 when in its purest state, a bright metallic lustre, and 
 crystallising in the rhombohedral system, and in com- 
 bination with water forming various hydrates, among 
 which are brown hematite, limonite, &c. It may be' 
 made artificially by calcining protosulphate of iron 
 at a strong red heat, the salt, by its decomposition, 
 giving rise to sulphuric and sulphurous acids, and a 
 bright red pulverulent peroxide known as rouge, col- 
 cot/iar, or crocus, which is extensively used as a polishing 
 material by glass and metal workers. The reactions 
 in this process, which is employed commercially in the 
 manufacture of fuming or Nordhausen sulphuric acid 
 are as follows : 
 
 2 FeO. SO 3 = Fe' : 3 + SO 2 + SO 3 . 
 
 Pulverulent varieties of the same substance, but 
 differing in colour and tenacity, may be obtained by the 
 calcination of other salts of iron as follows : 1, from 
 fc e pernitrate, which yields a nearly black product ; 2, 
 from the persulphide, giving a rouge suitable for gold- 
 smiths this requires a long-continued, and finally, 
 rather a high heat ; and 3, from the neutral protoxalate, 
 which gives a very finely divided product. 
 
 A brilliant variety occurs in small steel- grey crys- 
 tals in the hollows of lavas from Yesuvius and other 
 
OUTLINE OF THE CHEMISTRY OF IRON. 23 
 
 volcanoes. One of the finest examples of this kind, 
 brought from Ascension Island, is now in the Museum 
 of Practical Geology. It may be artificially imitated 
 by calcining protosulphate of iron at a strong red-heat 
 with, three times its weight of chloride of sodium. 
 The latter salt is unaltered, and may be dissolved out 
 with water ; the residue is peroxide of iron in brittle 
 and crystalline scales of a dark violet or nearly black 
 colour. These brilliant varieties are distinguished by 
 mineralogists as specular iron, iron glance, or oligistic 
 iron. 
 
 Peroxide of iron is also found crystallised in regular 
 octahedra in the mineral known as Mar tit e, which be- 
 longs to the cubical system ; it occurs in conjunction 
 with the rhombohedral variety in lavas from Vesuvius 
 and other localities, and also in the slaty hematites of 
 Lake Superior. 
 
 The true composition of this mineral is rather doubt- 
 ful. It has been sometimes considered as a pseudo- 
 niorph of magnetite. Rammelsberg found in octahedral 
 crystals from the eruption of Vesuvius in 1855 as much 
 as 15 per cent, of magnesia, and has described them as 
 magnoferrite. He is not, however, prepared to regard 
 this as necessarily a new definite member of the spinel 
 or R :3 4 group, but considers it to be a dimorphous form 
 of the peroxide, containing magnesia in isomorphous 
 mixture, the peroxides and protoxides being capable 
 of replacing each other without change of form. This 
 view, if further extended, would make magnetite only a 
 particular variety of octahedral hematite, in which the 
 two isomorphous oxides are to each other in equivalent 
 proportions, and would fairly explain the deviation in 
 composition of nearly all magnetites from the theoretical 
 
24 METALLURGY OF IRON. 
 
 formula sometimes one and sometimes the othei 
 oxide being in excess of the required amount. 
 
 Peroxide of iron forms a series of salts parallel to 
 those of the protoxide, but it is difficult to obtain them 
 of a neutral composition, as their solutions have a ten- 
 dency to decompose into basic and acid salts, the former 
 usually precipitating, while the latter remain in solution. 
 
 At ordinary temperatures the peroxide is a very 
 stable substance ; it may, however, be decomposed by 
 heating it nearly to a white heat, when magnetic oxide 
 is formed with evolution of oxygen ; thus 
 
 3Fe 2 3 = 2Pe 3 4 + 0; 
 
 a reaction which explains why magnetic oxide is pro- 
 duced when iron is burnt in oxygen, the temperature 
 of the combustion being too great to allow of the exist- 
 ence of the higher oxide. 
 
 Hydrates of Peroxide of Iron. The hydrate produced 
 by precipitation from the solution of a persalt of iron, 
 or by spontaneous oxidation from the hydrated peroxide, 
 consists of two equivalents of peroxide of iron combined 
 with three of water, or 2 F 2 3 . 3 H 2 0. It forms the base 
 of a large class of minerals known as earthy brown 
 hematite or limonite, and is the ultimate product of 
 the alteration of any substance containing protoxide of 
 iron when exposed to the action of atmospheric air and 
 moisture. 
 
 When boiled in water for seven or eight hours, the 
 hydrated protoxide loses water, and is reduced to the 
 form of Fe 2 3 . IPO, which is a brick- red powder but 
 slightly soluble in. acids, and also occurs in nature 
 beautifully crystallised in the minerals gothite, lepi- 
 (iocrocite, &c. 
 
OUTLINE OF THE CHEMISTRY OF IRON. 25 
 
 The last equivalent of water may be removed, and 
 anhydrous peroxide obtained, by heating the hydrate 
 in a solution of chloride of calcium, or common salt, foi 
 several days, at a temperature of 160 to 180. 
 
 Ilydrated peroxide of iron is sensibly soluble in water 
 containing carbonic acid, or any soluble organic salt of 
 ammonia, such as are produced by the decomposition 
 of vegetable matter. In the latter case the solution is 
 attended with a reduction, and the formation of a proto- 
 salt of the organic acid. 
 
 Magnetic Oxide of Iron. This compound, one of the 
 most important commercial sources of iron, is formed of 
 equal equivalents of the per- and protoxide, or FeO + 
 Fe 2 3 , or short Fe 3 4 . It is a black mineral of high 
 lustre, crystallising in the regular system, the com- 
 monest forms being either octahedra or dodecahedra, 
 which may be artificially imitated by passing steam 
 over iron wire at a red heat, when small brilliant black 
 octahedra are formed on the surface of the metal. The 
 natural mineral is always magnetic, often polar, and 
 occasionally forms magnets capable of supporting con- 
 siderable weights. The two latter conditions do not 
 depend so much upon purity of composition as upon 
 molecular structure, as they are best developed, not in 
 the purest crystallised varieties, but rather in the com- 
 pact slaty kinds, which often contain a considerable 
 amount of foreign, especially earthy, matter. 
 
 The 6ther compounds of the two oxides of iron, which 
 are formed by the oxidation of wrought iron when 
 heated to redness in the air, have already been noticed 
 ander the head of Protoxide. 
 
 Hydratcd Magnetic Oxide of Iron. When freshly 
 precipitated hydrate of protoxide of iron is boiled iu 
 
 c 
 
26 METALLURGY OF IRON, 
 
 water, hydrogen is evolved, and a hydrate of the mag- 
 netic oxide is formed. According to Lefort, two 
 different hydrates may be obtained by pouring solu- 
 tions containing both proto- and persulphate of iron 
 into boiling potash or soda in excess. When the 
 salts of the two oxides are to each other in the pro- 
 portion of equal equivalents, we obtain 2 (FeO + Fe 2 3 ) 
 3 H 2 0, and in the second case, where the persalt is to 
 the protosalt as 1 to 6, the resulting hydrate is of the 
 composition 6 FeO + Fe 2 3 -f 4 IPO. Similar results 
 may be obtained with cold solutions by the use of am- 
 monia as a precipitant. 
 
 Magnetic Peroxide of Iron. Malaguti states that 
 whenever carbonate or any organic salt of protoxide of 
 iron is heated in the air until the acid is completely 
 dissipated, a pure peroxide is obtained, which is always 
 magnetic ; and also, that when the hydrated peroxides 
 produced by the spontaneous action of the air upon 
 hydrated protoxide, or iron rust, which processes are 
 always accompanied by the formation of ammonia, are 
 calcined at a gentle heat, similar magnetic varieties of 
 the peroxide are produced; while, on the other hand, the 
 peroxide produced from the decomposition of a persalt 
 is not in any degree magnetic, either before or aftei 
 calcination. 
 
 The above statements are disputed by De Luca, who 
 supposes that probably the magnetic effect is due to a 
 small quantity of protoxide, not altered by the low 
 heat employed, as the property is lost when the oxide 
 is subjected to a higher temperature. Probably these 
 contradictory views may be reconciled by assuming 
 that peroxide of iron is under certain conditions slightly 
 magnetic, but that the property is fugitive and may bo 
 dissipated by heat. 
 
OUTLINE OF THE CHEMISTRY OF IRON. 27 
 
 It is not a little remarkable that the only chemist 
 who has succeeded in obtaining protoxide of iron 
 should describe it as non-magnetic. Rammelsberg 
 found the octahedral peroxide from Vesuvius, contain- 
 ing 15 per cent, of magnesia, to be magnetic. 
 
 There is a large class of minerals analogous in con- 
 positioii to magnetite, represented by the formula RO + 
 R 2 3 , known as the Spinel group, in which the pro- 
 toxides are those of magnesium, zinc, iron, or manganese, 
 and the peroxides alumina and peroxide of iron. Some 
 of these substances have been formed artificially, among 
 them are, magnetite (FeO. Fe 2 3 ), black spinel (MgO. 
 APO 3 ), franklinite (ZnO. MnO. Fe 2 3 ) ; and magno- 
 ferrite (MgO. Fe 2 3 ). The latter substance, artificially 
 produced by Deville, has been described by Raminels- 
 berg as occurring in the products of the eruption of 
 Vesuvius in 1855. 
 
 Ferric Acid. This, the highest known oxide of iron, 
 has the formula FeO 3 , and is very similar in its pro- 
 perties to the corresponding oxide of manganese, MxiO 3 , 
 or manganic acid. It may be formed, among other 
 methods, by fusing finely divided iron with four times 
 its weight of nitre, or by passing a current of chlorine 
 through a concentrated solution of caustic potash con- 
 taining peroxide of iron in suspension. In the latter 
 method the following reaction takes place : 
 
 6 Cl -}- 5 E?0 + Fe 2 3 = 6 KC1 + 2 K 2 OFe0 3 ; 
 
 the ultimate products being chloride of potassium and 
 ferrate of potash. The latter salt, being insoluble in 
 excess of alkali, is slowly precipitated, if the solution 
 of potash be sufliciently strong, as a black powder, 
 which may be dried on unglazed porcelain, but is 
 immediately decomposed when brought into contact 
 
28 METALLURGY OF IKON. 
 
 with filtering paper or any organic matter. It is 
 soluble in water, giving a fine red solution, which is 
 slowly decomposed when evaporated, even in vac-tic, 
 with the production of potash, peroxide of iron, and 
 oxygen. No 011^ has as yet succeeded in isolating 
 ferric acid from its potash salt. 
 
 Iron and Nitrogen. The effect of nitrogen upon 
 iron, and more especially steel, has attracted the atten- 
 tion of many chemists, and several elaborate memoirs 
 have been published at different times on this subject. 
 Unfortunately, however, the results obtained by dif- 
 ferent chemists are so contradictory, that it is impossible 
 at present to decide with any degree of certainty as to 
 whether nitrogen plays an important part in deter- 
 mining the good qualities of steel or not. All that will 
 be attempted in this place will be to give a short 
 analysis of the principal -researches published up to the 
 present time. 
 
 According to Fremy, when iron wire is heated to 
 dull redness for several hours in a current of ammonia- 
 cal gas, it increases in weight from 12 to 13 per 
 cent., and shows but little tendency to alteration when 
 exposed to the action of the air. The nature of this 
 change is not well understood, as it is not certain 
 whether the product contains hydrogen or not. A 
 similar substance is formed by acting on protochloride 
 of iron with ammonia vapour at a red heat, the chloride 
 being decomposed with the production of sal-ammoniac, 
 peroxide of iron, and an amide salt, which in its turn 
 is destroyed by the water present, forming ammonia 
 and peroxide of iron. The residue of the operation is a 
 fritted mass, partly fused, and often containing a greyish, 
 brilliant, metallic-looking mass, which is nitride of iron 
 
OUTLINE OF THE CHEMISTRY OF IRON. 29 
 
 This substance is less oxidisable than pure iron, and may 
 be made permanently magnetic, although less perfectly 
 than steel. By heating in a brasqued or carbon- 
 lined crucible, it acquires the property of hardening 
 when plunged into Water at a red heat. Although it 
 may be heated to redness in air without change, it is 
 immediately decomposed when heated in an atmo- 
 sphere of hydrogen, ammonia and pure iron being 
 formed. The amount of nitrogen absorbed is said to 
 be about 9J per cent., which corresponds in composi- 
 tion to Fe 5 N. 
 
 According to Savart, however, the increase in weight 
 of iron wire exposed to the action of ammonia vapour 
 for nine hours is only y-fo or about -J- per cent. At 
 the end of one or two hours the iron shows a finely 
 granular fracture, and can be rendered sufficiently 
 hard, by quenching in cold water, to give sparks when 
 struck with a flint ; but when the process has con- 
 tinued from eight to ten hours a more than ordinarily 
 soft iron is obtained, no longer susceptible of temper- 
 ing, and of a dark grey colour and graphitic appear- 
 ance on a fractured surface. Dick obtained a similar 
 small increase in weight, amounting to about -^TTT when 
 a spiral iron wire was heated to redness in a current of 
 ammonia for one hour and a quarter, and only Y^TT 
 when a straight and thicker wire that is, one present- 
 ing less surface was substituted. 
 
 Bouis and Boussingault have determined the amount 
 of nitrogen contained in various kinds of commercial 
 iron, as well as in an artificial nitride prepared by 
 Despretz; the latter contained about 2| per cent., 
 while in the former the nitrogen varied from ris to 
 | per lent. 
 
30 METALLURGY OF IRON. 
 
 Iron and Phosphorus. Iron may "be made to com- 
 bine with phosphorus at a red heat, either directly or 
 during the reduction of an oxide of iron in the pre- 
 sence of an earthy phosphate and carbon, the latter 
 condition being of very common occurrence in metal- 
 lurgical practice. Percy, in a systematic account of 
 the phosphides of iron, describes no less than seven, as 
 follows : 
 
 1. Fe 12 P. Formed by dropping phosphorus on to red-hot iron. 
 
 2. FeP. heating Fe 2 P. 
 
 3. Fe 4 P. ,, reducing protophosphate of iron with carbon. 
 
 4. Fe-P. exposing iron reduced by hydrogen to phos- 
 
 phorus vapour at a low temperature. 
 
 6, Fe 8 P 3 . reducing sesquiphosphate of iron with hydro- 
 
 gen at a white heat. 
 
 6. Fe 5 P 2 . acting on phosphuretted copper and iron with 
 
 nitric acid. 
 
 7. Fe 8 P 2 . passing phosphuretted hydrogen over iron 
 
 pyrites at a low heat. 
 
 The composition and properties of the combinations 
 of iron and phosphorus have been reinvestigatecl by 
 Freese, who has arrived at results (Poggendorf, Annal- 
 zen, vol. cxxxii., p. 225) differing in some particulars 
 from those obtained by former observers. The method 
 principally adopted for the formation of the phosphides, 
 consisted in heating metallic iron or its compounds in 
 a current of phosphuretted hydrogen, produced by the 
 action of caustic potash lye upon amorphous phos- 
 phorus; the gas so obtained not being subject to spon- 
 taneous ignition when brought in contact with the air. 
 Berzelius's method of fusing phosphate of iron with 
 carbon was also employed. Freese states that only 
 three definite compounds can be obtained by these 
 means ; they have the following atomic and percentage 
 compositions : 
 
OUTLINE OF THE CHEMISTRY OF IRON. 31 
 
 Sp. gr. Phosphorus. Iron. 
 
 I. Fe s P 2 . 5-04 57-53 52-47 
 
 II. Fe 2 P. 6-21 42-47 57'53 
 
 III. Fe<P. 6-74 21.68 78.32 
 
 The first of the above compounds is produced by the 
 action of pliosphoretted hydrogen at a red heat upon 
 iron reduced by hydrogen ; it is described as a dark 
 bluish- grey non-magnetic powder, infusible and un- 
 alterable in the air at ordinary temperatures, but 
 burning, when heated, with an evolution of phosphorus, 
 whereby it becomes reduced to the compound Fe 2 P. 
 It may also be formed from anhydrous protochloride 
 of iron, or magnetic pyrites, as well as from metallic 
 iron. The phosphide Fe 2 P is formed by heating proto- 
 sulphide of iron, FeS, in phosphuretted hydrogen ; it 
 is generally similar to the former one, but is somewhat 
 lighter in colour. When heated it burns, but without 
 giving off phosphorus, and the resulting phosphate 
 contains both oxides of iron. The most basic of 
 the three phosphides, Fe 4 P, is formed by exposing a 
 mixture of 3J parts of phosphate of iron and 1 of 
 lamp-black, under a covering of common salt, in a 
 crucible to a white heat for four hours. The fused 
 mass is afterwards treated with weak hydrochloric acid, 
 in order to remove the salt and the excess of undecom- 
 posed phosphate, the quantity of carbon employed being 
 insufficient to reduce the whole of the latter salt, so as 
 to prevent the formation of carburized iron. The 
 residue of this operation is light a grey crystalline 
 powder, which is non-magnetic, and in other respects 
 very like the higher phosphides previously described. 
 
 When heated in hydrogen, carbonic oxide, or car- 
 bonic acid, none of the phosphides of iron show any 
 
32 METALLURGY OF IRON. 
 
 sign of fusibility ; but in air they are more or less 
 completely oxidized with the formation of phosphates. 
 "With the higher ones, this change is only superficial, 
 the crust of phosphate protecting the powder under- 
 neath from further action ; but the lower form, Fe 4 P 
 is completely altered, and fuses to a dark crystalline 
 mass, having a metallic lustre. The fusibility usually 
 attributed to the last-mentioned phosphide is, accord- 
 ing to Freese, due to its containing iron, and carbon 
 as impurities. 
 
 When any phosphide of iron is heated with hydro- 
 chloric acid it is very slowly, but entirely, decomposed, 
 the phosphorus being partly evolved as phosphoretted 
 hydrogen, and partly oxidized to phosphoric acid, the 
 proportion of the former to the latter being as 5 to 3 ; 
 the oxygen and hydrogen in the two compounds stand- 
 ing in the same atomic relation to each other, as they 
 do in water. 
 
 Phosphate of Iron. Of the numerous class of salt 
 formed by the oxides of iron and phosphoric acid, only 
 one is of any great interest, namely, the natural 
 mineral known as Vivianite, a product of alteration by 
 partial oxidation of the tribasic phosphate of the pro- 
 toxide, its composition being 
 
 6 (3 FeO. P 2 5 ) + (3 Fe 2 3 . 2 P 2 5 ) + 8 H 2 0. 
 It is very commonly formed in wet ground from 
 decaying animal or vegetable matter containing 
 phosphates, such as hard wood, or more especially 
 bones and teeth of animals, when brought in con- 
 tact with water containing a protosalt of iron in 
 solution. Beech trees growing in soils containing iron 
 pyrites, which by decomposition yield protosulphate of 
 iron, often deposit vivianite in their stems and roots 
 
OUTLINE OF THE CHEMISTRY OF IRON. 33 
 
 while still living, from the absorption of the sulphate 
 which is decomposed by the phosphate of lime present 
 in the plant, with the production of insoluble phos- 
 phate of iron in the cells of the trunk. The wood 
 becomes very hard by this addition, and when the tree 
 is cut down the surface of the stump gradually assumes 
 a greenish-blue colour by the absorption of oxygen 
 from the air. The same mineral is also common in the 
 bones and teeth of animals that have become imbedded 
 in peat bogs, either as a dull blue incrustation or 
 occasionally in small acicular crystals in the cavities, 
 and occurs at times in the organic remains con- 
 tained in impervious clays. An example of this is 
 furnished by the fossils contained in the Oxford clay 
 in Buckinghamshire, where the shells have at times 
 entirely disappeared, leaving only a hollow cast in the 
 stiff clay, the cavity being often lined with small 
 tufts of vivianite and gypsum, derived from the mutual 
 reaction of the products of decomposition of the soft 
 parts of the animal and the mineral matter of the 
 shell. 
 
 Phospnorus is one of the most unwelcome ingre- 
 dients in iron ores, from the ease with which it passes 
 into the metal during the smelting process, producing 
 the most injurious effects if present in more than a 
 very small proportion. 
 
 Wrought iron containing not more than yV per 
 cent, of phosphorus, is not sensibly affected in tenacity, 
 but is only rendered somewhat harder ; with J per 
 cent, it becomes somewhat cold short, or incapable of 
 being wrought cold under the hammer without break- 
 ing: with T 8 iT per cent, the cold shortness is very 
 dccidul ; and 1 per cent, makes the metal very brittle. 
 
 <J u 
 
34 METALLURGY OF IRON. 
 
 The tenacity of cast iron is also sensibly diminished by 
 phosphorus, so that the metal made from, the worst 
 kinds of bog ores cannot be employed for castings 
 requiring great strength ; but this is counterbalanced 
 by the properties of acquiring great fluidity, and 
 taking good impressions, which render it proper to 
 be used for small and intricate ornamental castings. 
 
 Arsenic and Iron readily unite, forming compounds 
 which may be subjected to a high degree of heat 
 without decomposition. These compounds are usually 
 known by the German term, Speiss, and are of common 
 occurrence in the smelting of arsenical silver and lead 
 ores when the reduction of the sulphide of lead is 
 effected by iron. They are found in thin layers 
 of a columnar crystalline structure between the reduced 
 lead and the supernatant regulus of copper and other 
 sulphides when the molten contents of the furnace are 
 allowed to settle in a basin after tapping. The ordi- 
 nary composition of such a speiss is represented by 
 the formula Fe 6 As. ; when nickel or cobalt is present 
 in the ore it invariably passes into it. 
 
 Although arsenic and iron are found in combina- 
 tion in a great variety of minerals both as arsenides 
 and arseniates, yet, as none of them are used as iron ores, 
 nor do they as a rule occur in any quantity as acci- 
 dental admixture with such ores, it is rarely that 
 arsenic is found as an impurity in the metal. Two 
 instances are, however, recorded of its presence in 
 considerable amount in cast iron, both being in shot 
 and shell of Turkish origin, those brought from Sinope 
 containing 16*2 per cent., while of others found in the 
 arsenal at Algiers on the French occupation in 1830, 
 the shells contained 9 and the shot 27 per cent. Such 
 
OUTLINE OF THE CHEMISTRY OF IRON. 35 
 
 metal is very brittle, white, with a brilliant radiated 
 structure, and unfit for conversion into malleable iron 
 by the puddling process, as it yields bars which are 
 red short, or brittle at a red heat, although sufficiently 
 tenacious to bear hammering when cold. A smaller 
 amount of arsenic is, however, said to be beneficial when 
 the metal is intended for chill casting ; that is, for 
 castings whose surfaces are artificially hardened by the 
 use of cold metal moulds. 
 
 Sulphur and Iron. The compounds of sulphur and 
 iron are of considerable importance to the iron smelter, 
 as they are commonly present as impurities in many 
 iron ores, and impart the defect of red shortness to the 
 metal, even when only a very small proportion of sul- 
 phur is taken. The protosulphide, FeS., corresponding 
 in composition to the protoxide, is not found in nature, 
 but may be readily formed by dropping sulphur on to 
 heated scrap iron, or in the wet way by adding an 
 alkaline sulphide to the solution of any protosalt of iron. 
 When produced by the first method, it melts easily to a 
 dark bronzy-black mass, with a metallic lustre, which 
 combines readily with the sulphides of other metals, a 
 property which is largely utilised in the smelting of 
 copper and silver ores ; the so-called matte, coarse metal, 
 or regulus, is an example, being a sulphide of iron con- 
 taining more or less of the sulphides of the valuable 
 metals, which is obtained in the first fusion, whereby 
 the earthy matters in the ore are eliminated, and 
 the metallic contents concentrated for further treat- 
 ment. 
 
 The protosulphide is but slightly affected when 
 heated with ordinary reducing agents, such as carbon, 
 or even hydrogen, but may be almost completely decon> 
 
36 METALLURGY OF IRON. 
 
 posed at a high temperature by oxidising substances, 
 sueli as peroxide of iron or silica, or by the action of 
 air at a red heat, the change in the latter case being 
 accompanied by the formation of various sulphates of 
 both protoxide and peroxide ; the ultimate product, 
 however, being pure peroxide of iron. 
 
 The persulphide Fe 2 S 3 may be formed artificially, but 
 does not occur in nature in a free state, although it is 
 found in combination with the sulphides of other 
 metals, more especially those of copper. 
 
 Magnetic Pyrites, or Pyrrhotinc, 6 FeS + FeS 2 , the 
 most basic of the native sulphides of iron, is a bright 
 bronze-coloured mineral, crystallising in the rhombohe- 
 dral system, and remarkable for its magnetic properties, 
 which are, however, feebler than those of the magnetic 
 oxide. It is occasionally found in association with iron 
 ores, but more generally with those of copper and 
 nickel, as well as with native gold, being more especially 
 confined to crystalline rocks. 
 
 Bisulphide of Iron, FeS 2 . This is the well-known 
 substance which, under the name of iron pyrites, is 
 found in greater or less quantity in every member of 
 the geological series. Two principal varieties are dis- 
 tinguishable, namely, ordinary iron pyrites, which is of 
 a brassy-yellow colour, crystallising in the cubical 
 system, and marcasite, or white iron pyrites, a rhombic 
 mineral, of a lighter colour, softer, and more readily 
 decomposed than the cubical kind. The percentage 
 composition is, iron 48, sulphur 52. 
 
 When heated in close vessels, iron pyrites is decom- 
 posed with partial separation of sulphur, which sublimes, 
 leaving a residue of proto- or perhaps magnetic sulphide. 
 If, however, the operation is conducted with a free 
 
OUTLINE OF THE CHEMISTRY OF IRON, 37 
 
 access of air, the sulphur burns to sulphurous acid, caus- 
 ing a great increase of temperature, and is ultimately 
 wholly expelled, leaving peroxide of iron behind, which, 
 if the pyrites employed be sufficiently pure, may be 
 used as an iron ore. The residues obtained from pyrites 
 in sulphuric acid manufacture are so employed in 
 Cleveland, under the name of Blue Billy. When exposed 
 to moist air, iron pyrites, especially the rhombic variety, 
 is rapidly changed to protosulphate of iron, and con- 
 versely, when the latter salt is brought into contact 
 with decomposing organic matter in situations where 
 air is excluded, pyrites is formed. It is probably in 
 this way that the greater part of the pyrites existing 
 in sedimentary rocks has been formed. 
 
 Sulphate of Protoxide of Iron. This salt, well known by 
 its commercial names of green vitriol or copperas, crystal- 
 lises in the oblique system, forming pale green crystals 
 having the composition FeO. SO 3 -\ 7 H 2 0. Like most 
 other salts of the same base, it is very susceptible of 
 oxidation, changing colour in the air even when crys- 
 tallised, but more rapidly when in solution, by the 
 absorption of oxygen and the formation of partly soluble 
 and partly insoluble sulphates of the peroxide. These 
 are very complex in composition, and are described at 
 length in the larger chemical text-books. Among them 
 are several minerals, such as coquimbite, copiapite, 
 misy, and others. 
 
 Iron and Chlorine. There are two chlorides of iron, 
 corresponding in composition to the two lower oxides, 
 or protochloride, FeCl, and perchloride, Fe 2 Cl 3 . The 
 former is produced when metallic iron is dissolved 
 in hydrochloric acid, and may be obtained in a hydrated 
 tbrm by concentrating the solution, when green crystals 
 
38 METALLURGY OF IKCVtf. 
 
 are deposited. These are doubly oblique in form, and 
 have the composition Fed -f 4 IPO. 
 
 When hydrochloric acid gas is passed over iron wire 
 hea,ted to redness, anhydrous protochloride is formed, and 
 condenses in the cooler portion of the tube in colourless 
 cubical crystals. The hydrated perchloride may be 
 prepared by boiling the protochloride with nitric acid, 
 by dissolving peroxide of iron in hydrochloric acid, or- 
 by the action of aqua regia on metallic iron. The 
 solution obtained by either of the above methods yields 
 on evaporation, rhombohedral crystals, whose composi- 
 tion is Fe 2 Cl 3 + 6 H 2 0. 
 
 The anhydrous perchloride is formed when diy 
 chlorine is passed in considerable quantity through a 
 porcelain tube containing iron wire heated to redness. 
 It crystallises in hexagonal scales, which deliquesce in 
 moist air. 
 
 When magnetic or other mixed ores, containing both 
 per- and protoxide of iron, are dissolved in hydrochloric 
 acid, both chlorides are formed in the solution, in the 
 same proportion to each other as that of the two oxides 
 in the substance operated tfpon. This property is of 
 great value to the analytical chemist, as by it he is 
 enabled to determine, in many cases, the state of oxida- 
 tion in which iron exists in the ore. 
 
 Iron and Silicon. According to Percy, iron does not 
 combine with silicon when heated with silica anless 
 carbon be present. Under the latter condition, 
 however, by reducing an intimate mixture o per- 
 oxide of iron and sand with charcoal in a wind 
 furnace, a variety of cast iron may be obtained con- 
 taining as much as 13 per cent, of silicon, which 
 is very hard and brittle. By effecting the reduc- 
 
OUTLINE OF THE CHEMISTRY OF IRON. 39 
 
 tion in a blast furnace, cast iron with. 6 to 18 per cent, 
 of silicon (Silicon-pig, or Ferro- silicon) may be obtained. 
 This is specially used in making soft steel castings in 
 order to obtain them free from blowholes. 
 
 Protosilicate of Iron. Protoxide of iron combines 
 readily with silica at the welding temperature of the 
 metal. Familiar examples of this property are furnished 
 by the use of sand in the smith's forge to remove the 
 scale formed during the heating of the iron, and also by 
 the so-called forge and mill cinders produced in the 
 welding of malleable iron by the puddling and reheat- 
 ing processes. 
 
 The whole of the above substances are essentially 
 dibasic silicates of protoxide of iron, represented by the 
 formula 2 FeO. SiO 2 , containing 70 per cent, of pro- 
 toxide of iron, and 30 per cent, of silica, which melts at 
 a white heat, becoming very liquid, and crystallising on 
 cooling. 
 
 When formed under favourable conditions the crystals 
 are often very perfect modified rhombic prisms,, analo- 
 gous in form to those of olivine, a silicate of magnesia 
 having a similar atomic constitution, which occurs 
 largely in volcanic rocks, and also in meteoric stones. 
 
 When heated with access of air, protosilicate of iron, 
 such as the slag of the puddling furnace, is decomposed, 
 the iron passes in great part into the state of peroxide, 
 and separates from the silica, giving a substance which, 
 under the name of "bull-dog/ 7 is largely used for 
 lining the hearths of puddling furnaces. The refractory 
 nature of this product is due to the infusible character 
 of the two oxides, and their inability to unite and fuse 
 together when exposed to an oxidising atmosphere. 
 
 By reference to the percentage composition given 
 
40 METALLURGY OF IRON. 
 
 above it will be seen that silica requires 2 times its 
 own weight of protoxide of iron to form a slag, or, what 
 is the same thing, one part by weight of silicon takes 
 up rather more than 3f parts of metallic iron. These 
 figures indicate the great loss of iron which takes place 
 in the refining of pig iron rich in silicon. 
 
 The iron contained in ptiddling-furnace cinder and 
 other slags of a similar character may be reproduced by 
 treating them in the blast furnace, either alone, or, what 
 is preferable, in admixture with the ordinary charges of 
 ore and flux. As, however, nearly the whole of the 
 phosphorus contained in the original ore is passed into 
 the slags during the process of puddling, the metal 
 produced from them is necessarily of very inferior 
 quality. The term cinder pig is applied to this kind of 
 iron, in contradistinction to mine pig, which is smelted 
 from ores alone. 
 
 Richardson found that when pure dibasic protosilicate 
 of iron was heated with carbon, two-thirds of the iron 
 was reduced to the malleable form, leaving a slag of 
 the composition 2 FeO, 3 SiO 2 . 
 
 Silicon renders malleable iron hard and brittle. win 
 
 o 
 
 to the ease, however, with which this element can be 
 removed in the manufacture, it is rarely present in 
 quantity sufficient to exert a marked influence. On 
 cast iron its effect is very similar to that of carbon, and 
 as both are of common occurrence in, and exert an im- 
 portant joint influence on, pig iron, it will be more 
 convenient to consider this point subsequently. 
 
 Iron and Carbon. Combination between iron and 
 carbon may be readily effected in several different ways, 
 cither by the direct action of carbonaceous fuel, or 
 more properly carbonic oxide gas, at a high tempera- 
 
OUT.TESE OF THE CHEMISTRY OF IRON. 
 
 41 
 
 ture, as takes place in the reduction of ores by the blast 
 furnace, or by maintaining the metal in a compact 
 state, such as ordinary bar iron, for a lengthened period 
 at a lower temperature in contact with charcoal, com- 
 pounds containing cyanogen, or the vapour of hydro- 
 carbons. The latter process, called cementation, is applied 
 on a large scale in the manufacture of steel. 
 
 As has been already stated in the introductory para- 
 graphs, the iron of commerce is divided into wrought 
 iron, steel, or cast iron, according to the amount of 
 carbon taken up, the proportion in the different varieties 
 being, according to Karsten, as follows : - 
 
 Name. 
 
 Percentage of 
 Carbon. 
 
 Properties. 
 
 1. Malleable iron 
 
 0-25 
 
 Is not sensibly hardened by sudden 
 
 
 
 cooling. 
 
 I 2. Steely iron . 
 
 0-35 
 
 Can be slightly hardened by 
 
 
 
 quenching. 
 
 ,3. Steel . . . 
 
 0-50 
 
 Gives sparks with a flint when 
 
 
 
 hardened. 
 
 4. do. . . . 
 
 1-00 to 1-50 
 
 Limits for steel of maximum hard- 
 
 
 
 ness and tenacity. 
 
 5. do. . . . 
 G. do. ... 
 
 1-75 
 1-80 
 
 Superior limit of welding steel. 
 Very hard cast steel, forging with 
 
 
 
 great difficulty. 
 
 7. do. . . . 
 
 1-90 
 
 Not malleable hot. 
 
 3. Cast iron . . 
 
 2'00 
 
 Lower limits of cast iron cannot 
 
 
 
 be hammered. 
 
 9. do. ... 
 
 6-00 
 
 Highest carburetted compound ob- 
 
 
 
 tainable. 
 
 Condition of Carbon in Iron. Carbon may be con- 
 tained in cast iron either in chemical combination, or 
 diffused through the mass in the form of crystals of 
 graphite which have separated from the molten metal 
 in cooling. The latter variety is known as grey, and 
 the former as white, cast iron. 
 
 When grey cast iron is dissolved in an acid, its 
 
42 METALLURGY OF IRON. 
 
 graphitic carbon remains unaltered in the insoluble 
 residue ; but when the white variety is similarly treated, 
 only a small portion of the carbon separates, the com- 
 bined portion uniting with the hydrogen evolved from 
 the water decomposed during the solution of the 
 metal, and forming hydrocarbons which are partly 
 liquid and partly volatile : the latter have a very fetid 
 smell. 
 
 By sudden cooling, as in the process of chill casting, 
 grey cast iron may be rendered white : the effect is 
 usually only superficial, the interior still retaining its 
 greyness. 
 
 According to Caron, the state in which carbon exists 
 in steel depends upon the treatment to which the metal 
 has been subjected. The softer qualities contain it as 
 graphite, which is liable to pass into combination by 
 hardening or hammering ; by annealing, the graphitic 
 character is restored. It would appear from this that 
 chill casting and the hardening of steel are probably 
 due to the passage of carbon from the free to the com- 
 bined state. 
 
 Much has been written at different times by numerous 
 observers on the probable atomic composition of the car- 
 bides of iron, but great diversity of opinion still prevails 
 on this point. Karsten supposed Spiegeleisen, or specular 
 pig iron, the most highly carbonised and crystalline 
 white metal, to be a carbide of the composition Fe 4 C, 
 which would contain 5 '08 per cent, of carbon. Dick, 
 however, was unable to obtain white iron by reducing 
 perfectly pure sesquioxide of iron with an excess of pure 
 carbon at the highest temperature of an assay furnace, the 
 result being a grey button of metal containing about 4| 
 per cent, of uncombined carbon. As Spiegeleisen. how- 
 
OUTLINE OF THE CHEMISTRY OF IRON. 43 
 
 ever, contains a notable quantity of manganese, it 13 
 probably the latter metal that influences the combina- 
 tion of the carbon, and that the carbide, if it exist 
 at all, may be represented as (FeMn) 4 0, but its 
 existence has not as yet been determined by experi- 
 ment, 
 
 Rammelsberg states that Karsten's formula for 
 Spiegeleisen cannot be established, even supposing the 
 carbon to be partly replaced by silicon, as the 
 largest quantity of the latter element is found in the 
 most highly carburetted varieties ; thus, Miisen Spie- 
 geleisen contained 05 of silicon, that of Magdesprung 
 0*17 per cent., and Styrian, with only from 3'75 to 4-14 
 per cent, of carbon, but O'Ol to 0-027 per cent. 
 
 Guiit has endeavoured to establish the existence of 
 a lower carbide corresponding to the formula Fe 8 C, 
 which he supposed to stand in the same relation to 
 grey, that Karsten's tetracarbide, Fe 4 C, does to white 
 cast iron. This compound was supposed to have been 
 found at Gleiwitz, in Silesia, crystallised in octahedra 
 in the hollows of unsound castings made of dark grey 
 iron, which on analysis yielded 
 
 Carbon combined . . . . 2 '46 
 
 graphitic . . . . 2 '84 
 
 Silicon 0-26 
 
 Iron 94-20 
 
 99-76 
 
 The formula deduced from this is Fe 8 (O.Si), the silicon 
 taking the place of a portion of the carbon. 
 
 Eammelsberg, on the other hand, states that these 
 and similar crystals from other localities are probably 
 only metallic (malleable) iron, containing variable 
 
44 
 
 METALLURGY OF IRON. 
 
 amounts of impurities, such as carbon, silicon, phospho- 
 rus, and sulphur, and that their composition cannot be 
 expressed by Gurlt's formula unless all these foreign 
 matters are supposed to replace a portion of the carbon. 
 
 Kalle mentions a fact observed by Richter at the 
 Prussian ordnance foundry at Spandau, which appears 
 to confirm Rammelsberg's opinion. When dark grey 
 iron was melted and exposed to the highest heat 
 attainable in a reverberatory furnace, the amount of 
 combined carbon was reduced to 0'12 per cent, out of a 
 total of 3 per cent. Guns cast from this over-heated 
 metal, which failed on proof, were found to be sensibly 
 bulged near the muzzle, and in one instance the bore 
 increased gradually, indicating a decided softness. 
 Kalle therefore supposes that such metal may be con- 
 sidered as a mixture of malleable iron and graphite, 
 the almost entire separation of the combined carbon 
 being due to the excessive heating. 
 
 Graphitic carbon is found to a small extent in white 
 iron, as is seen in the following analyses by Bromeis 
 of cast iron from Magdesprung, in the Harz. 
 
 Name. 
 
 Combined 
 Carbon. 
 
 Graphitic 
 Carbon. 
 
 Total. 
 
 
 Per Cent. 
 
 Per Cent. 
 
 Per Cent. 
 
 1. Bright white iron . . 
 2. White forge pig . . 
 
 2-518 
 2-908 
 
 0-500 
 0-500 
 
 3-018 
 3-458 
 
 3. Spiegel eisen . . . 
 
 3-100 
 
 0-720 
 
 3-820 
 
 Dark grey cast iron, in addition to uncombined car- 
 bon, often contains silicon in the same state, the latter 
 element being capable of assuming a graphitic cha- 
 racter. It occurs more particularly in the products of 
 hot blast furnaces working in difficultly reducible ores. 
 
OUTLINE OF THE CHEMISTRY OF IROK. 45 
 
 Very white iron, on the other hand, is produced from 
 easily reducible ores, especially those containing man- 
 ganese, with a low fuel consumption. 
 
 When sulphur to the extent of about 2 J per cent, is 
 melted with grey cast iron, a portion of the carbon 
 separates in a sooty form, and an intensely hard white 
 metal is produced. With a smaller quantity of from 
 ^ to J per cent, a mottled iron of great strength is 
 obtained, which, when broken, shows a quantity of grey 
 spots, enclosed by reticulating lines of white, on the 
 fractured surface. The well-known Swedish gun- 
 foundry iron is of this character, a small portion of 
 sulphur being introduced by the use of an ore containing 
 a little iron pyrites, and admixture with the ordinary 
 charge of the blast furnace. 
 
 The method of imparting carbon to malleable iron 
 so as to form compounds less highly carburetted than 
 cast iron, by exposing it, at a temperature below its 
 melting point, to the long-continued action of charcoal, 
 is called cementation, and the product of the operation 
 is known as cement or blister steel. A similar effect is 
 produced more rapidly when the iron is heated in coal 
 gas, or the vapour of a volatile hydrocarbon, such as 
 paraffine, instead of charcoal. The superficial cementa- 
 tion of wrought iron by heating it for a short time in 
 contact with carbonised leather or cyanogen compounds 
 is termed case hardening. 
 
 The exact cause of the change effected in bar iron 
 by cementation has not been conclusively determined, 
 and has recently been the subject of a long- continued 
 controversy between two French chemists, Messrs. 
 Fvemy and Caroii, in the proceedings of the Academy 
 of Sciences at Paris, the essential point in dispute being 
 
46 METALLURGY OF IROJs. 
 
 the necessity or otherwise of nitrogen for the production 
 of steel. Fremy considers that cast iron and steel are 
 not simply compounds of iron and carbon, but that the 
 presence of other elements is necessary, such as sul- 
 phur, phosphorus, silicon, arsenic, and nitrogen, but 
 more especially the latter. The following extraordi- 
 nary analysis, said to be of a first class razor blade 
 made from Dannemora iron, is quoted in support of 
 this view : 
 
 I. II. 
 
 Carbon. , . v . 1'43 . . 0-087 
 
 Sulphur , v ., . 1-00 . . 0-220 
 
 Silicon. ^ . . 0-52 . . 0-115 
 
 Antimony . ... 0*12 
 
 Arsenic .'. . . 0'93 . . trace 
 
 Phosphorus . . . . 0'034 
 
 Nickel . ' . . . . 0-18 
 
 Manganese . ' .' . 1'92 
 
 Iron . 93-80 . 99'544 
 
 99-90 100-00 
 
 Analysis II. of Dannemora iron by Henry is sufficient 
 to show that the steel in question could not have been 
 produced by the ordinary processes of steel manufacture. 
 
 The general classification of commercial iron according 
 to Fremy's hypothesis is as follows : 
 
 1. Wrought iron is more or less pure iron, the softest 
 kinds being the purest. 
 
 2. Cast iron is iron combined with more or less of 
 carbon, part of which may be replaced by silicon. 
 
 3. Steel is a ternary compound of iron, carbon, and 
 nitrogen, or nitro-carburetted iron. 
 
 Caron, on the other hand, while admitting the value 
 of nitrogen in facilitating the conversion of malleable 
 
OUTLINE OF THE CHEMISTRY OF IRON. 4? 
 
 iron into steel, is not disposed to consider it as an essen- 
 tial ingredient on account of the very small amount 
 that can be discovered in steel by analysis. 
 
 The contradictory results obtained by different che- 
 mists who have attempted to form nitrides of iron have 
 already been noticed at p. 28. 
 
 Dick found that electrotype iron was more readily 
 converted into steel by cementation in an atmosphere 
 of hydrogen than the best sheet iron, a fact that bears 
 heavily against Fremy's view, as the metal was remark- 
 able for softness and purity, and was free from nitrogen. 
 
 Marguerite, in a recent article, states that steel is 
 formed when iron is heated with diamond dust in 
 hydrogen, or alone in carbonic oxide. In the latter 
 case carbon separates from the gas and is taken up by 
 the metal, and carbonic acid is produced. When silicon 
 is present it- is oxidised to silica at the expense of the 
 carbonic oxide, also with a separation of carbon. 
 
 A new theory of cementation has recently been pro- 
 pounded by Graham, founded upon the property pos- 
 sessed by iron of dissolving carbonic oxide at low tem- 
 peratures. 
 
 As the case stands at present, the weight of evidence 
 is certainly against the necessity of the existence of 
 nitrogen in steel, and it is most likely that the older 
 view of Karsten, that its essential qualities are due to 
 variations in the amount of carbon, is in the main 
 correct, although they may be modified by the presence 
 of other elements. 
 
 From what has been previously advanced as to the 
 composition of cast iron, the following propositions may 
 be deduced : 
 
 1. The greater part of the carbon is in white cast 
 
48 METALLURGY OF IRON. 
 
 iron chemically combined, and in grey diffused as 
 graphite. 
 
 2. Neither variety is, however, entirely free from 
 graphitic or combined carbon respectively. 
 
 3. Although containing carbon in chemical com- 
 bination, there is no certain evidence of the existence of 
 any denned carbide in white iron, but Spiegeleisen 
 may possibly be a double carbide of iron and man- 
 ganese. 
 
 4. Dark grey iron is not a lower carbide of iron than 
 Spiegeleisen, but is probably only a mixture of malle- 
 able iron and graphite, and its chemically combined 
 carbon may be reduced to a minimum by intense heating 
 when melted. 
 
 5. Silicon is a common constituent of grey cast iron. 
 
 6. Chill casting, and the addition of sulphur, tend 
 to produce whiteness in grey cast iron, and a similar 
 change may be effected in steel by hardening or forging. 
 
 The combination of mechanical with chemical analy- 
 sis has been recently applied to the investigation 
 of the composition of cast iron by Mr. Gr. J. Snelus, of 
 Dowlais. He found that when very grey pig iron was 
 reduced to a coarse powder in a steel mortar, scales of 
 graphite were removed from the crystalline facets of 
 the iron, and these, when subjected to combustion, were 
 entirely converted into carbonic acid without leaving 
 any residue, proving them to be even purer than 
 natural graphite. A large proportion of the gra- 
 phitic carbon can also be separated when borings of 
 grey pig iron are sifted through fine silk gauze, or levi- 
 gated with water ; the finer and lighter portions in 
 <3ach instance retaining the largest amount of carbon, as 
 shown in the following percentage determinations. 
 
OUTLINE OF THE CHEMISTRY OP IRON. 
 
 
 Original Carbon. 
 
 Fine 
 
 Siftings. 
 
 Light 
 Washings. 
 
 1. Bessemer pig . . 
 
 f Graphitic 3'34 
 \ Combined 
 
 9-11 
 
 28-41 
 
 
 | Graphitic 3- 19 
 
 7-79 
 
 21-27 
 
 n 
 
 \ Combined 0-20 
 
 0-17 
 
 __ 
 
 3. Cleveland forge pig . 
 
 1 Graphitic 2-65 
 \ Combined 0-35 
 
 7-02 
 0-30 
 
 41-33 
 
 i 
 
 
 
 
 These results show clearly that in grey pig iron the 
 free or graphitic carbon can be more or less perfectly 
 separated by mechanical means, while the combined 
 carbon decreases in the same ratio as the residual iron. 
 On the other hand, no separation of silicon could be 
 effected by this method ; for instead of increasing in 
 the finer and lighter portions, as the graphite does, it 
 actually decreases with the increase of the latter, thus 
 proving that even in the most highly siliciferous 
 pigs the whole of the silicon is in the state of com- 
 bination. 
 
 Cast iron free from manganese contains a little more 
 than 4 per cent, of carbon at most,* which may be 
 divided between the combined and graphitic condi- 
 tions in very variable proportions, graphite being most 
 abundant; carbon and silicon are about equal. This 
 is known as dark grey or No. 1 foundry iron. A 
 slight excess of silicon over carbon gives glazed or 
 glazy pig iron, but when the former substance exceeds 
 about 5 per cent, the metal is known as silicon pig or 
 ferro-silicon. When manganese is present in cast iron 
 a very much larger proportion of carbon may be taken 
 up and retained in the combined condition. Thus low 
 spiegel, with less than 15 per cent, of manganese, con- 
 tains from 4*5 to 5*5 per cent, of carbon ; while in high 
 
 * For newer views on carbon and iron see page 511. 
 D 
 
50 METALLURGY OF IRON. 
 
 ferro-manganese, with more than 80 per cent, of 
 manganese, the carbon approaches to 7 per cent. It 
 seems likely therefore that pure manganese pig con- 
 taining carbon and manganese only, supposing it pos- 
 sible to obtain it, would carry twice as much carbon as 
 pure cast iron, or about 8 per cent. This condition 
 cannot, however, be realised in practice, as some silicon 
 is invariably reduced in the smelting furnace. 
 
 Of the influence of other Metals on Iron Alloys of 
 Iron. Iron alloys with gold, the metals of the platinum 
 group, zinc, tin, aluminum, manganese, nickel, cobalt, 
 and chromium, but not with copper, silver, or lead. 
 It may be melted in all proportions with copper, but 
 no combination takes place except zinc or tin be present. 
 About 1 per cent, of iron adds considerably to the 
 tenacity of copper or brass, a property which is utilised 
 in the alloys known as stcrro metal and delta metal. 
 Formerly it was considered that copper to the extent 
 of 0*4 0*5 per cent, was prejudicial to iron or steel, 
 producing red shortness in a similar manner to sulphur, 
 but later researches have shown that 0'8 per cent, may 
 be present in soft steel without any marked effect. 
 
 Zinc and Iron do not form any useful alloy ; about 
 7 per cent, of the latter metal may be taken up when 
 zinc is kept melted in cast-iron pots, or when its vapour 
 is passed through wrought-iron tubes. The former con- 
 dition prevails in the process called galvanising, or the 
 zincing of sheet iron by immersion in melted zinc. 
 The cast-iron pots used for holding the molten metal, 
 where exposed to the greatest heat, are slowly corroded 
 with the formation of an alloy which does not differ 
 much in appearance from metallic zinc. The formation 
 of this substance is a source of considerable loss in the 
 
OUTLINE OF THE CHEMISTRY OF IRON. t>l 
 
 manufacture, but may be prevented by filling the pot 
 to a certain height with melted lead, upon which the 
 zinc floats, and only comes in contact with iron at a 
 temperature below that necessary for combination. This 
 alloy is utilised in the production of the copper, zinc, 
 and iron alloy known as delta metal. 
 
 Tin and Iron. These metals unite in almost every pro- 
 portion, but their alloys are not employed as such in the 
 arts. When applied in a similar manner, however, to zinc 
 in the galvanising process that is, when sheet iron is 
 immersed in a bath of melted tin the well-known 
 tin-plate is produced. An inferior variety, coated with an 
 alloy of tin and lead, is called terne-plate. Malleable 
 iron containing 0'5 per cent, of tin is hard, but cannot be 
 hammered cold, and welds with difficulty. Cast iron 
 with about 5 per cent, of tin is hard, and breaks with 
 a fine steely fracture ; it has been tried as an alloy for 
 casting bells. Tin with 2 per cent, of iron is magnetic, 
 sensibly duller in lustre than the pure metal, and hard 
 and short in fracture. 
 
 An alloy of 10 parts of iron with 60 or 80 of tin is 
 recommended for use in tinning copper utensils, in pre- 
 ference to pure tin. 
 
 Antimony, when present in very small quantity, from 
 0*1 to 0*3 per cent., acts very injuriously upon mal- 
 leable iron, rendering it in the highest degree both hot 
 and cold short. The so-called martial regulus, containing 
 7 parts of antimony to 1 of iron, is recommended for 
 producing casts of medallions and other relief im- 
 pressions in preference to cast iron. 
 
 Nickel unites readily with iron in all proportions. In 
 natural meteoric iron it is present between 3 and 17 
 per cent., and such iron is remarkable for its ductility 
 
52 METALLURGY OF IRON. 
 
 and resistance to rusting. An addition of 5 per cent, 
 of nickel to mild steel is found by Mr. James Riley to 
 increase the tensile strength from 30 to 47 tons p 
 square inch, while the ductility is but slightly diminished. 
 Similar results have been obtained by Mr. J. F. Hall at 
 Sheffield with nickel steel gun barrels. Although iron 
 and nickel are the most highly magnetic metals known, 
 their alloys are but slightly, if at all, susceptible of 
 magnetism. Cobalt acts similarly to nickel. 
 
 Chromium, when added in the proportion of about 
 1 per cent., communicates great strength and stiffness 
 to steel,* which is used for armour-piercing projectiles. 
 In smaller proportion (0-4 per cent.) it has been used to 
 harden mild steel for railway tyres without materially 
 reducing its ductility. 
 
 Aluminum alloys readily with iron. Such alloys, 
 known as ferro-aluminum and aluminum steel, are used 
 as tempering materials in making castings from soft; 
 iron melted in crucibles by Nordenfelt's process (p. 513). 
 
 Faraday and Stodart found that platinum alloyed 
 readily with steel, and produced a very tough and fine- 
 grained product when present to the extent of 1 per cent. 
 Similar results were obtained with the other metals of 
 the same group, palladium, rhodium, and osmiridium. 
 
 Tungsten renders cast steel very hard and tenacious, 
 but practically destroys its ductility. Alloys containing 
 up to 40 per cent, of tungsten may be produced by 
 reducing a mixture of tungstic and ferric oxide, or 
 wolfram (tungitate of iron and manganese) with charcoal 
 in crucibles. This alloy (ferro-tungsten] when added to 
 the charge in making crucible steel, produces Mushet's 
 special steel, tungsten steel, or wolfram steel, with 5 to 
 * See also page 501. 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 53 
 
 ]2 per cent, of tungsten, which is the hardest class of 
 tool steel, and is used in turning down the faces of 
 chilled- cast iron rolls. Tools forged from it require no 
 tempering. It also retains permanent magnetism better 
 than any other class of steel. 
 
 Vanadium was found in minute quantities by Sefstrom 
 in iron made from the magnetic ore of Taberg, in 
 Sweden, and also in the pisolitic ores of the Jura, both 
 being noted for yielding first-rate iron for wire drawing. 
 
 Titanium may be present in pig iron to the extent of 
 about 1 per cent, when a proportion of titanif erous ore 
 is added to the charge. It increases the strength of the 
 metal, at the same time giving it a peculiar mottled 
 character. It is doubtful whether any portion of the 
 titanium is retained in the bar iron or steel made from 
 such pig iron. 
 
 Manganese influences the properties of soft iron and 
 steel in a very remarkable manner, the effect varying 
 with the proportion. For details, see page 
 
 CHAPTER III. 
 
 COMPOSITION AND DISTRIBUTION OF IRON ORES. 
 
 AMONG the numerous minerals containing iron, only 
 the oxides and carbonates can be used by the smelter. 
 They are as follows : 
 
 1. Magnetic Iron Ore, or Magnetite, crystallises in the 
 cubical system, usually in octahedra or rhombic dode- 
 cahedrons, but more generally massive, varying in 
 texture in the fracture from coarsely crystalline to finely 
 granular, or even massive. Colour black, with occa- 
 sionally a slight greenish or brown cast. Streak black. 
 Magnetic, and sometimes polar. Specific gravity 5-2. 
 
54 METALLURGY OF IKON. 
 
 Composition, FeO + Fe 2 3 , containing 724] per cent 
 of iron. 
 
 2. Franklinite. Cubical, crystallising in octahedra; 
 also massive ; very similar in colour and general appear- 
 ance to magnetite, but less magnetic, and gives a dark 
 reddish-brown streak. Specific gravity, 5*1. Compo- 
 sition, 3 (FeO. ZnO. MnO) + (Fe 2 3 . Mn 2 3 ). The 
 average of several analyses by Eammelsberg gives 
 
 Iron . ''' . V . 4516 
 
 Manganese . . . >;; 9'38 
 
 Zinc . ...". . . 20-30 
 
 Oxygen . . , . 25-16 
 
 100-00 
 
 It is a rare substance, being found only at two or three 
 localities in New Jersey, where it occurs in metamorphic 
 Silurian limestone as a bed from 20 to 30 feet thick, 
 overlaid by from 6 to 8 feet of red zinc ore. Both 
 minerals are first treated for zinc, and the residues are 
 then smelted for Spiegeleisen. 
 
 3. Hematite. Ehombohedral, crystallising usually in 
 highly modified rhombohedral or scalenohedral forms ; 
 combined with the terminal plane of the prism ; the 
 latter, by its prominence, usually giving a tabular form 
 to the crystals. Also in fibrous, columnar, botryoidal, 
 granular, pisolitic, and compact forms. Colour varies 
 from brilliant bluish grey in the crystallised, to a deep 
 red in the compact, varieties ; the streak is red in all 
 cases. Specific gravity, 5-3 for crystallised, down to 
 4*2 in some earthy varieties. Sometimes very slightly 
 magnetic. Composition, Fe 2 3 , with 70 per cent, of 
 iron. Special names are given to the different varieties 
 as follows : 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 55 
 
 Specular Iron Ore, Oligiste, or Iron Glance, includes 
 the brilliant, hard, well- crystallised forms, such as 
 those of Elba, Brazil, Vesuvius, &c. 
 
 Micaceous Iron Ore includes all the scaly crystalline 
 varieties, such as those of South Devon, which are 
 loosely coherent, and similar to graphite in structure. 
 
 Kidney Ore, or Bother Glaskapf, includes the hard bo- 
 tryoidal forms, such as those of Cumberland, which are 
 devoid of metallic lustre. 
 
 Red Ochre and Iron Minium are compact earthy 
 varieties, often containing clay, which are ground and 
 used as colours. 
 
 Puddter's Ore is a peculiar, unctuous, compact form, 
 from Cumberland, which is largely used for lining the 
 hearths of puddling furnaces. 
 
 The term, Red Hematite, is commonly used by English 
 iron- smelters for all minerals consisting essentially of 
 anhydrous peroxide of iron. 
 
 4. Ilmenite, or Titaniferous Iron Ore. Rhombohedral, 
 the crystals being similar in general appearance to 
 those of hematite ; they are, however, rare, the mineral 
 being usually found massive. Colour dead black, 
 with a brownish streak; fracture conchoidal. Specific 
 gravity, from 4- 5 to 5. Contains protoxide and peroxide 
 of iron, titanic acid, and magnesia in very variable 
 proportions. The following types of composition have 
 been established by Hammelsberg : 
 
 I. FeO. TiO 2 , containing 52 -63 titanic acid, and 
 47*37 protoxide of iron. 
 
 II. FeO. TiO 2 + MgO. TiO 2 containing 58'82 tita- 
 nic acid, 26'47 protoxide of iron, and 14'71 mag- 
 nesia. 
 
 III. mFeO. TiO 2 4- M Fe 2 3 , or isomorphous mixtures 
 
56 METALLURGY OF IRON. 
 
 of titanate of protoxide of iron with peroxide in inde- 
 finite proportions, the observed limits being 
 
 9 FeO. TiO 2 -f Fe 2 3 and 
 FeO. TiO 3 + 13Fe 2 3 ; 
 
 the former containing 47-12 and the latter only 3 '55 
 per cent, of titanic acid. 
 
 Turgite, or Hydrohematite. This resembles hematite 
 in colour and streak, but is of lower density, 4'2 to 4*7. 
 The composition is 2 Fe 2 3 -f H 2 0, or ferric oxide 947, 
 water 5'3 per cent. "When compact it is a dull brick 
 red substance , a fibrous crystalline variety from 
 Salisbury, Connecticut, exactly like kidney hematite, 
 decrepitates violently when heated. 
 
 Gbthite. This crystallises on the rhombic system in 
 well-defined forms, and also occurs in scaly, fibrous, and 
 other crystalline aggregates. Specific gravity, 4*0 to 
 4'4. Colour varies from rust-yellow to rich brown or 
 black ; streak brown. The fibrous kinds have a peculiar 
 velvety lustre. Composition, Fe 2 3 + H 2 0, or ferric 
 oxide 90-5 (metallic iron 63-0), water 10 -5, per cent. 
 
 Brown Iron Ore. Limonite. These are compact and 
 earthy minerals that consist essentially of three equiva- 
 lents of water united to two of peroxide of iron, or 
 2Fe0 3 + 3H 2 0; the percentage of composition, corre- 
 sponding to the formula, being peroxide of iron 85 6 
 (metallic iron 59 -9), and water 14'4. They vary in 
 colour from light brown to black. Streak yellowish 
 brown. Specific gravity, 3 '6 to 4. 
 
 Both hydrates of peroxide of iron are usually included 
 in the smelter's term brown hematite, signifying minerals 
 which, although resembling hematite proper in outward 
 appearance, can readily be distinguished by their brown 
 streak. In Staffordshire, the term hydrate of iron is some- 
 
times used. Bog iron ores, and those deposited in the 
 beds of lakes by infusorial action, belong to the same 
 class. 
 
 Siderite. This is the mineralogical name of carbo- 
 nate of protoxide of iron, which crystallises in the rhom- 
 bohedral system. The commonest forms are rhombo- 
 hedra ; hexagonal prisms, and scalenohedra, being less 
 frequent. In a massive form, it occurs in isolated nodules, 
 or occasionally in connected beds. Specific gravity, 
 3*7 to 3'9. Lustre of crystals pearly ; colour usually 
 some shades of yellowish brown or grey, owing to the 
 formation of a superficial coating of hydrated peroxide ; 
 the streak is white, representing the true colour of the 
 unaltered mineral. Composition, FeO. CO 2 , with 62*07 
 per cent, of protoxide of iron (48 '22 metallic iron), and 
 37*93 per cent, of carbonic acid. A portion of the base 
 is, however, almost invariably replaced by protoxide of 
 manganese, lime, or magnesia, the former oxide varying 
 in quantity from to 59 per cent, in different varieties. 
 
 The purer crystalline varieties are called spathic ores 
 by the smelter ; while the term clay land, or clay iron- 
 stone, is applied to the amorphous argillaceous ore found 
 in the coal measures, and black band to that contain- 
 ing bituminous or carbonaceous matter. On the Con- 
 tinent, nodular clay ironstone is usually called sphero- 
 siderite ; but this term more properly belongs to the 
 spheroidal crystalline masses of radiating structure, 
 occasionally found in basalt and other igneous rocks. 
 
 The septaria, or cement-stone nodules, found in the 
 London clay, may be regarded as clay ironstones in 
 which the protoxide of iron is in great part replaced 
 by lime : such ores as are too poor to smelt are known 
 as lean ironstones. 
 
58 
 
 METALLURGY OF IRON. 
 
 Association and Distribution of Iron Ores. The defi- 
 nitions of iron ores given in the preceding paragraphs 
 are mineralogical ; that is, they present the physical 
 and chemical characteristics of iron-producing minerals 
 when at a maximum of purity. Practically, however, 
 no such pure minerals are to be found on the large 
 scale, and it therefore becomes necessary to consider the 
 manner in which iron ores and other minerals are asso- 
 ciated together. The presence of foreign minerals is 
 often as largely concerned in determining whether an 
 ore can be worked to profit or otherwise, as its rich- 
 ness in iron. Thus, a magnetite or hematite deposit, 
 containing 10 per cent, of phosphate of lime or iron 
 pyrites, would be almost useless ; while the same amount 
 of manganese in a spathic, or of combustible matter in 
 an argillaceous carbonate, would considerably enhance 
 their respective values. "We shall next proceed, there- 
 fore, to illustrate these associations by describing some 
 of the more typical iron-mining localities, accompany- 
 ing the descriptions with analyses of the minerals 
 actually raised. 
 
 The geological distribution of iron ores is very mi- 
 equal ; for, although, they are found in formations of all 
 ages, the maximum development appears to be in the 
 older rocks. The largest and richest deposits are con- 
 tained in pre-Silurian strata, such as the Laurentian 
 and Huronian series of North America, and the old 
 gneiss and schists of Scandinavia. Spathic ores are 
 characteristically abundant in the Devonian rocks of 
 Grermany and the south of England, being associated 
 in the former locality with red and brown hematites of a 
 high class. The carboniferous period is especially 
 marked by the presence of interstratified argillaceous 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 59 
 
 carbonates both, in Europe and America. The most 
 important deposits of red hematite in this country are 
 of Permian age, and are contained in hollows of the 
 carboniferous limestone of Cumberland and Lancashire. 
 In the secondary rocks the chief iron-bearing members 
 are the middle lias, or marlstone, great oolite, wealden, 
 and lower green sand, yielding brown hematites and 
 carbonates which, though of low quality, are of con- 
 siderable importance, owing to the ease with which they 
 may be mined. In France and Southern Germany large 
 quantities of bean ore, an argillaceous brown hematite, 
 are raised from pipes and other irregular deposits in the 
 oolitic rocks. The tertiary rocks of this country contain 
 very little iron ore, the principal deposit being at Hen- 
 gistbury Head, in Dorsetshire ; but on the Continent 
 the magnificent masses of Elba and Traversella may, 
 perhaps, be of tertiary age. 
 
 Of post- tertiary and recent age are the numerous 
 masses of bog iron ore studded over the swamps of 
 Northern Germany, and the lake ores which are con- 
 stantly forming by infusorial agency at the bottom of 
 the lakes of Norway, Sweden, and Finland. 
 
 Magnetic Ores. When massive, these ores usually in- 
 dicate an excess of peroxide over that required by the 
 formula. They are chiefly confined to the older crystal- 
 line rocks of Scandinavia and North America, and 
 appear under two principal conditions: either inter- 
 stratified in irregular beds or tabular masses in horn- 
 blendic and cnloritic schists and crystalline limestones, 
 or irregular ramifying veins and masses in dioritic or 
 doleritic rocks. The associated minerals are usually 
 chlorite, hornblende, epidote, garnet, idocrase, phos- 
 phate of lime, quartz, felspars, iron and copper pyrites, 
 
60 
 
 METALLURGY OF IRON. 
 
 lievrite, hematite, and brown iron ores. The latter 
 are found chiefly near the surface, and occasionally 
 beautifully crystallised in transverse veins. In the 
 Swedish and Norwegian mines the ore is very com- 
 monly intersected by small strings of chlorite called 
 skolar. Iron pyrites may be either disseminated in 
 considerable quantity through the ore, which in sucn 
 cases it generally renders useless, or interspersed in 
 small patches in the neighbourhood of veins of intrusive 
 rock, such as granite. Sometimes the centre of a mass 
 may be pure magnetite, passing at either side into 
 copper and iron pyrites. The texture of massive mag- 
 netite appears to vary with the containing rock ; the 
 most compact, having sometimes a nearly conchoidal 
 fracture, are found in talcose schist, while the more 
 granular and crystalline conditions prevail in horn- 
 blendic gneiss and crystalline limestones. 
 
 In the oldest or Laurentian rocks of Canada mag- 
 netite is found abundantly in the gneiss and meta- 
 morphic limestones of the basin of the Ottawa. The 
 usual form of deposit is in irregular beds, which, al- 
 though not of any great lateral extent, are often of 
 considerable thickness, in one instance as much as 200 
 feet. These ores are usually of a very high quality, 
 the associated minerals being chiefly quartz, hornblende, 
 chlorite, serpentine, dolomite, and graphite, but have 
 hitherto only been raised in inconsiderable quantities. 
 
 The largest deposit of iron ore in Europe is probably 
 that of Gellivara, in Swedish Lapland, which is situated 
 about ninety miles from, the head of the Gulf of Bothnia, 
 in lat. 67 N. According to the descriptions of Erd- 
 mann and others, it forms a bold hill rising out of 
 swampy ground, made up of a great number of parallel 
 
COMPOSITION AND DISTRIBUTION OF IKON ORES. 61 
 
 interlaminations of magnetic and specular iron ores, 
 with hornblendic and quartzose rocks. Several of these 
 beds are between 100 and 200 feet in thickness, and 
 may be traced for distances of 600 and 700 yards in a 
 N.E. and S.\Y. direction. Phosphate of lime is present 
 in the largest, or 200-feet bed, through about 80 feet 
 of its thickness, the remaining 120 feet being of good 
 quality. Iron pyrites appears to be almost entirely 
 absent. The following analyses of Grellivara ores are 
 by Binman : 
 
 
 I. 
 
 II. 
 
 in. 
 
 IV. 
 
 Silica 
 
 2-10 
 
 3-20 
 
 3-10 
 
 5-95 
 
 Alumina 
 
 0-70 
 
 0-85 
 
 0-85 
 
 1-05 
 
 Lime 
 
 2-10 
 
 0-45 
 
 2-35 
 
 2-40 
 
 Magnesia 
 
 0-70 
 
 1-30 
 
 0-60 
 
 2-50 
 
 Glucina 
 
 
 
 
 
 0-10 
 
 
 
 Magnetic oxide of iron 
 Phosphoric acid . 
 
 92-10 
 1-70 
 
 93-45 
 0-45 
 
 90-65 
 M7 
 
 87-80 
 0-09 
 
 
 99-40 
 
 99-70 
 
 98-82 
 
 99-79 
 
 Metallic iron 
 
 67-3 
 
 677 
 
 65-6 
 
 63-5 
 
 Although these ores have been known for a very long 
 period, but little use has been made of them, owing to 
 the inaccessible character of the country, but latterly 
 they have been brought into communication by railway 
 with the coast, and are exported to England. 
 
 In the southern part of Sweden the most celebrated 
 mines are those of Dannemora, situated on the lake of 
 the same name, about thirty-two miles from Upsala. 
 The ore, which is specially employed for producing the 
 highest class of steel iron, is a very fine-grained mag- 
 netite, occurring in an irregular interrupted belt about 
 one mile and a half long, in crystalline limestone and 
 
62 
 
 METALLURGY OF IRON, 
 
 petrosilex. The workings on the central part of the 
 mass have been extended to a depth of more than 100 
 fathoms below the surface. The annual production is, 
 however, small, not exceeding 25,000 tons : 
 
 
 I. 
 
 II. 
 
 III. 
 
 Peroxide of iron 
 Protoxide of iron 
 Protoxide of manganese 
 Lime 
 Magnesia . 
 
 58-93 
 27-55 
 
 o-io 
 
 0-38 
 0-61 
 0'29 
 
 62-06 
 28-42 
 
 traces 
 1-44 
 
 56-80 
 27-50 
 0-24 
 1-80 
 0-80 
 
 Sulphur . 
 Carbonic acid . 
 Water 
 Silica 
 Phosphoric acid 
 
 0-04 
 0-12 
 0-11 
 12-54 
 trace 
 
 0-07 
 7-60 
 
 13-20 
 
 Metallic iron .... 
 
 100-67 
 62-6 
 
 99-59 
 65-6 
 
 100-34 
 61-16 
 
 Analysis No. I. of Dannemora ore, by Ward, is of 
 a compact black mineral, containing a very small 
 trace of iron pyrites. Nos. II. and III., by Noad, 
 are of magnetic ores from Eoslagen, on the east coast 
 of Sweden, north of Stockholm. No. II., from Hdcksta 
 mine, is coarsely crystalline and very slightly coherent, 
 breaking up into sand when subjected to pressure. 
 No. III., from Sladdero Island, is remarkable for its 
 regular structure being divided by joints into rhom- 
 boidal prisms. These divisions have been mistaken at 
 times for cleavages of the regular octahedron, but that 
 they are not is evident from their passing through 
 the adjacent gneissic rock, imparting to it a similar 
 structure to that noticed in the ore. Iron pyrites, in 
 small quantities at least, is not uncommon in the mag- 
 netic iron ores of southern Sweden, especially in the 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 63 
 
 neighbourhood of granitic veins : an instance of this 
 is afforded by the Jerna mines, situated in an out- 
 break of coarse granite, and yielding an ore which, 
 although spotted through with iron pyrites, is valu- 
 able as an addition to the purer ores of the more 
 northerly districts in the manufacture of strong foundry 
 iron. 
 
 Among the most remarkable deposits of magnetic 
 iron in the more southern parts of Europe is that of 
 Traversella, in Piedmont, situated about twelve and a 
 half miles from Ivrea, in the valley of Bersella. It occurs 
 in talcose schists and dolomites in the form of a largely 
 crystalline mass, consisting chiefly of magnetic iron ore, 
 but associated with an extraordinary profusion of other 
 minerals, such as copper and iron pyrites, garnet, 
 chlorite, dolomite, and augite, most of which are beauti- 
 fully crystallised. The workings have been carried 
 on from time immemorial. About forty miles of galleries 
 have been driven, and the mass, whose thickness varies 
 from 65 to 100 feet, has been removed, at one point, to 
 a depth of more than 200 yards for a distance of about 
 a quarter of a mile. The central portion is formed by 
 an ellipsoid of extremely pure magnetite, accompanied 
 by dolomite, and yielding from 48 to 50 per cent, of 
 iron. The sides are more or less charged with copper 
 pyrites in sufficient quantity to be profitably separated 
 by means of electro-magnetic machines. 
 
 At Berggieshiibel, in Saxony, magnetite occurs under 
 somewhat similar associations to those observed at Tra- 
 versella. The deposits are parallel beds from a few 
 inches to twenty feet in thickness, carrying red and 
 brown hematite with sulphate of baryta at the surface, 
 passing downward into magnetite, with garnet, horn- 
 
64 METALLURGY OF IRON. 
 
 blende, and epidote ; and at still greater depths, coppei 
 ores appear in considerable quantity. 
 
 In the neighbourhood of Arendal, in Norway, a 
 series of deposits of magnetite have been worked for 
 several centuries. They extend in a nearly straight 
 line for about thirteen miles parallel to the coast, and 
 are contained in hornblendic and micaceous schists. 
 The ore is mostly pure magnetic oxide without admix- 
 ture of hematite, and appears in elongated lenticular 
 masses from 6 to 20 feet, but occasionally as much as 70 
 feet in thickness, whose course is, as a rule, parallel to 
 the foliation of the containing rocks. 
 
 The Taberg, near Jonkoping, on Lake Wettern, is 
 an example of the second class of magnetite deposits, 
 where the ore is interspersed in comparatively small 
 strings and masses through a porphyritic rock com- 
 posed of hornblende and felspar (greenstone or diorite), 
 It forms an isolated hill 366 feet in height, and is 
 extensively wrought, although the produce is low, con- 
 taining on an average only 25 per cent., as the metal 
 produced is specially adapted for wire-drawing, and fuel 
 is comparatively cheap in the neighbourhood. 
 
 At Nischne-Tagilsk and Kuschwinsk, in the Urals, 
 magnetite occurs under somewhat similar conditions to 
 those observed at Taberg, but in a doleritic (labradorite 
 and augite) porphyry. At the former locality, a ridge 
 of rock, 600 yards long, 500 yards broad, and about 250 
 feet high, is in great part made up of pure magnetic 
 ore ; while at the latter it appears to be interspersed 
 through the mass of the augitic porphyry, and towards 
 the summit segregates into a rich workable mass. 
 
 In England magnetic iron ore is comparatively rare 
 Near Brent, in South Devon, it is found covering diorite 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 65 
 
 in a crust of about one foot in thickness, the association 
 being similar to that observed in the Urals. At Tres- 
 kerby, near Penryn, it occurs in a lode about three feet 
 in width, with a slight intermixture of tin ore. 
 
 The Cerro Mercado, near Durango, in Mexico, a hill 
 about 300 feet high, is in great part composed of massive 
 magnetite, which in the transverse fissures separates 
 out into octahedral crystals of an inch in diameter. 
 The associated minerals are specular and brown hema- 
 tite, quartz, and calcspar. The deposit is contained in 
 a felspathic porphyry, fragments of which are found 
 in the ore. Other large deposits of a similar character, 
 on the Pacific side of the country, are supposed by Dana 
 to be contemporaneous in origin with those of Canada 
 and the Northern States of America. 
 
 Red Iron Ores. These are often associated with the 
 hydrated varieties of the peroxide, especially in the 
 more earthy deposits contained in secondary and newer 
 rocks ; but in the harder crystalline masses, charac- 
 terising the older formations, such admixtures are less 
 frequent, except near the surface, or in cross fractures, 
 which often contain gothite and other crystalline forms 
 of brown hematite. The most important deposits of 
 these minerals in Europe and America are contained in 
 Huronian, or Cambrian, Silurian, Devonian, and car- 
 boniferous rocks. In Sweden, the specular or micaceous 
 variety of hematite occurs, among other places, at Dal- 
 karlsberg, near Nora, and in the island of Uto, in both 
 places associated with magnetite. The Nora ore is 
 made up of parallel stripes of a very brilliant mica* 
 ceous hematite and quartz, and resembles in compo- 
 sition the Brazilian rock known as itabirite. 
 
 On the south shore of Lake Superior, near Mar- 
 
66 METALLURGY OF IRON. 
 
 quetfce, a schistose variety of hematite, known as specular 
 schist or slate iron, is very largely developed in the 
 Huronian rocks. The iron region extends westward 
 from the lake shore for a distance of about twenty miles 
 with a breadth averaging six miles. The strata, which 
 are intensely contorted, are chiefly chloritic and talcose 
 schists, passing upward into a rock composed of parallel 
 laminae of red jasper and hematite, whose total thick- 
 ness is stated to be upwards of a thousand feet. Out 
 of this amount much is too siliceous, from the great 
 prevalence of jasper, to be worth working ; but indi- 
 vidual beds of solid hematite, free from earthy matter, 
 of 150 feet thickness, are quarried at the Jackson and 
 Superior mines. A noticeable peculiarity in these ores, 
 in addition to their intensely contorted structure, is 
 the prevalence of minute crystals of the octahedral 
 variety of peroxide of iron, or martite. There are 
 numerous cross veins of secondary origin containing 
 crystallised brown iron ores, and occasionally disul- 
 phicle of copper in small quantity. Specular schists of 
 a similar character, very finely laminated or contorted, 
 have also been observed on the Canadian shore of Lake 
 Superior, as well as in the altered beds of the Quebec 
 group, belonging to the Lower Silurian series, but on a 
 much smaller scale. 
 
 Two celebrated masses of hematite, known as the 
 Iron Mountain and Pilot Knob, are worked near St. 
 Louis, in Missouri. The former consists mainly of 
 massive or specular ore, while the latter is of a similar 
 schistose character to that of the Lake Superior mines. 
 
 In Saxony red iron ores are found in the vicinity of 
 Eibenstock and Schwarzenberg, in lodes at the con- 
 tact of mica schist, altered Silurian rocks, and granite. 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 67 
 
 These lodes, some of which are as much as 15 fathoms 
 thick, extend longitudinally for nearly twelve miles. 
 
 The Devonian rocks, both of England and Germany, 
 contain considerable quantities of red hematite, chiefly 
 in association with brown and spathic iron ores. At 
 Biixham, in Torbay, a brilliant micaceous variety is 
 found in limestone, and is employed, when ground in oil, 
 as a paint for covering iron work. A similar substance, 
 of a brilliant red colour, is obtained at Audeghem, in 
 Belgium, which is sold for the same purpose, under the 
 name of " minium de fer," and is recommended for 
 use in coating marine boilers in preference to red-lead. 
 
 The largest deposit of iron ore in Cornwall is that 
 worked at Restormel, near Lostwithiel, where a lode, 
 having an average thickness of from 12 to 16 feet, 
 occasionally increasing to 20 feet, has been followed 
 for more than a mile. The principal mineral is crys- 
 tallised brown hematite or gothite, which occurs in 
 fibrous and mammillated aggregates, and also in long 
 prismatic crystals of great beauty. Less frequent are red 
 hematite, and hard and soft manganese ores. Crystals 
 of carbonate of iron altered to brown hematite are 
 occasionally seen in the upper levels. Owing to the pre- 
 valence of manganese, these ores are well adapted for 
 making steel irons. 
 
 By far the most important hematite mines in this 
 country, are those of Ulverstone, in Lancashire, and 
 Whitehaven, in Cumberland, which occur in very 
 irregular deposits in the carboniferous limestone. Near 
 Oleator, the ore forms a bed of from 15 to 60 feet in 
 thickness, apparently interstratified between a shale 
 floor and a limestone roof. It is for the most part of a 
 dull compact character, but forming kidney-shaped 
 
68 
 
 METALLURGY OF IRON. 
 
 crystalline aggregates in the cavities where crystals of 
 quartz and arragonite are also common, together with 
 specular iron. In the Ulverstone district the ore is 
 usually found filling irregular cavities in the limestone. 
 In addition to the compact, a greasy micaceous variety 
 is largely produced, and is used for lining the hearths 
 of puddling furnaces. In both districts brown hema- 
 tite appears to be entirely absent; iron pyrites and 
 phosphate of lime can be detected in minute traces 
 chemically, but are not apparent to the naked eye. 
 The following analyses are sufficient to show the 
 extreme purity of these ores : 
 
 
 I. 
 
 II. 
 
 III. 
 
 Peroxide of iron 
 
 90-36 
 
 95-16 
 
 94-23 
 
 Protoxide of manganese . 
 Alumina .... 
 
 o-io 
 
 0-37 
 
 0-24 
 
 0-23 
 0-51 
 
 Lime .... 
 
 0-71 
 
 0-07 
 
 0-05 
 
 Magnesia .... 
 
 0-u6 
 
 
 
 
 
 Phosphoric acid 
 
 
 
 
 
 0-09 { Su ^ UnC 
 
 Bisulphide of iron 
 
 0-06 
 
 
 
 0-03 
 
 Insoluble residue 
 
 8-54 
 
 5-68 
 
 6-18 
 
 
 100-20 
 
 101-15 
 
 100-32 
 
 Metallic iron 
 
 63-25 
 
 66-6 
 
 65-96 
 
 Nos. I. and II. Hematites from Cleator Moor, Whitehaven, by Dick. 
 No. III. Lindale, Ulverstone, by Spiller. 
 
 Since the intoduction of the Bessemer process, a large 
 additional demand has sprung up for hematite pig 
 iron, and these ores are smelted to a great extent in 
 the immediate vicinity of the mines. In addition to the 
 local consumption, a considerable quantity is exported, 
 to other districts, some going to America, for use 
 either as a mixing ore or in the puddling furnace. 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 
 
 69 
 
 The following series of analyses gives the composition 
 of the red hematite ores, employed for making Bessemer 
 pig iron at Barrow-in-Furness iron works, Lancashire. 
 
 
 I. 
 
 ii. 
 
 in. 
 
 IV. 
 
 Peroxide of Iron . 
 Alumina .... 
 Protoxide of manganese , 
 
 9-1-88 
 0-07 
 0-04 
 0-34 
 
 77-24 
 1-71 
 0-11 
 6-08 
 
 83-33 
 0-75 
 0-08 
 4-10 
 
 83-94 
 0-70 
 0-2X 
 0-So 
 
 Magnesia . ... 
 
 Water . . - * 
 
 tiace 
 0-47 
 
 0-41 
 2-82 
 
 0-15 
 
 1-97 
 
 0-09 
 2-2S 
 
 Phosphoric acid 
 Sulphuric acid . 
 Carbonic acid . . . 
 
 0-03 
 
 4*55 
 
 4-19 
 7-36 
 
 trace 
 2-53 
 6-59 
 
 0-03 
 12-46 
 
 
 
 
 
 
 Metallic iron . . 
 
 100-38 
 66-42 
 
 99-92 
 54-07 
 
 9950 
 58-33 
 
 100-03 
 
 58-76 
 
 I. Park ore (best rough) ; II. Lindal Cote (puddling) ; 
 III. Whitrigg's (puddling) ; IY. Mouzell mine (best). 
 Analyses by Richards. 
 
 The tTlverstone and Furness districts are pre- 
 eminent among those producing iron ores suited for the 
 Bessemer process i.e. of high percentage and almost 
 absolute freedom from phosphorus. In this respect 
 they are only approached by the best of the Swedish 
 and Algerian ores, and those of the North of Spain. In 
 the United States the richer hematites and magnetites 
 are distinguished as Bessemer, or non-Bessemer ores, 
 according to the amount of phosphates present. The 
 former class includes only those ores that give when 
 smelted a pig iron containing less than (HO per cent, 
 of phosphorus. Latterly it has been found, both in 
 America and Sweden, that the phosphorus in granular 
 magnetic ores may be considerably reduced by the use 
 of electro-magnetic separating machines. 
 
70 METALLURGY OF IRON. 
 
 At Wliitclmrcli, near Cardiff, in Glamorganshire, an 
 oolitic variety of red hematite occurs at the base of the 
 carboniferous limestone. It is also found in the same 
 geological position in the valley of the Meuse, near 
 Huy and INamur, in Belgium ; and on the Cumberland 
 river, in Kentucky a curious fact, showing that 
 similar conditions prevailed at the commencement of 
 the carboniferous period in areas widely removed from 
 each other. 
 
 A remarkable bed of calcareous brown hematite 
 occurs in the Cheadle coal-field in North Staffordshire, 
 at the base of the coal measures. Although its maximum 
 thickness is only 22 inches, it has been extensively used 
 for export to South Staffordshire, where it is used as a 
 mixture with the more siliceous ores of other districts. 
 
 In the Forest of Dean, and in the neighbourhood of 
 Bristol, as well as at Llantrissant, in Glamorganshire, 
 irregular masses of brown hematite are met with in the 
 carboniferous limestone and the lower coal-measure 
 sandstones. At the last of the above-mentioned locali- 
 ties the ore is interstratified between the upper part 
 of the carboniferous limestone, in which it forms an 
 irregular bed, filling holes and depressions, and a 
 black shale roof, supposed to be a portion of the coal 
 measures, which is filled with nodules of argillaceous 
 carbonate of iron. The Forest of Dean ore is a stalac- 
 titic brown hematite, locally known as brush ore, the 
 more earthy varieties being distinguished by the term 
 smith ore. The following analyses give the composition 
 of the ores of this district : 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 71 
 
 BROWN HEMATITES FROM CARBONIFEROUS BOCKS. 
 
 
 I. 
 
 II. 
 
 III. 
 
 IV. 
 
 Peroxide of iron . 
 
 90-05 
 
 89-76 
 
 59-05 
 
 52-83 
 
 Protoxide of manganese 
 
 0-08 
 
 0-04 
 
 0-09 
 
 0-81 
 
 Lime 
 
 0-06 
 
 0-49 
 
 0-25 
 
 14-61 
 
 Alumina 
 
 
 
 0-63 
 
 
 
 
 
 Magnesia 
 
 0-20 
 
 0-40 
 
 0-28 
 
 5-70 
 
 Carbonic acid 
 
 
 
 
 
 
 
 18-14 
 
 Phosphoric acid 
 
 0-09 
 
 0-13 
 
 0-06 
 
 0-32 
 
 Sulphuric acid or pyrites 
 
 - 
 
 . 
 
 0-09 
 
 0-28 
 
 Silica . . 
 
 
 
 
 
 34-40 
 
 
 
 Water . 
 
 9-22 
 
 7-05 
 
 6-38 
 
 4-75 
 
 Organic matter 
 
 
 
 
 
 
 
 1-30 
 
 Insoluble residue 
 
 1-07 
 
 2-57 
 
 
 
 0-04 
 
 
 100-77 
 
 101-07 
 
 1QO-60 
 
 98-78 
 
 Metallic iron 
 
 63-04 
 
 62-86 
 
 41-34 
 
 36-98 
 
 No. I. Black brush ore, from Forest of Dean, by Dick, 
 II. Smith ore 
 
 III. Llantrissant ore, Glamorganshire, by Eiley. 
 IV. Calcareous hematite, "hydrate of iron," from Froghall, by Dick. 
 
 The brown hematite of Ashton Court, near Bristol, 
 is remarkable for occasionally containing fragments of 
 sulphate of baryta, interspersed like felspar crystals in 
 a porphyry. 
 
 On the east side of the island of Elba, specular 
 iron ore has been worked for a period of 2,500 years. 
 The deposits are contained in metamorphic rocks, 
 whose age is not precisely determined, being variously 
 stated as belonging to the carboniferous, cretaceous, 
 or tertiary periods. At Hio Marina, hematite partly 
 specular and partly massive, rests upon talcose schist, and 
 is covered by crystalline limestone, but the work has 
 recently been confined to turning over rubbish heaps 
 5eft by the old miners, which are piled up to a height 
 of 500 feet above the ground level. At Rio ATbane 
 
72 METALLURGY OF IRON. 
 
 and Terra Nera the mineral appears in lodes traversing 
 talcose schist, which send off numerous strings, en- 
 closing fragments of the rock, and afterwards overlie 
 it, forming beds of from 30 to 100 feet in thickness. 
 At Cape Calamita a similar ramifying lode is seen in a 
 limestone cliff which rises precipitously from the sea. 
 In 1887, 175,558 tons were exported, 122,558 to 
 America and 42,186 to England. 
 
 A schistose variety of hematite, somewhat similar in 
 character to that of Lake Superior, is found in the 
 Devonian limestones of Nassau. At the mine of Gottes- 
 gabe several beds of from 1J to 4 feet in thickness, 
 making up a total of from 36 to 40 feet, are inter- 
 calated in schistose calcareous greenstones and beds of 
 eisenkiesel a concretionary rock, made up of red and 
 brown iron ore and fragments of bright red jasper. 
 In the same formation irregular pockets of brown and 
 red ores, associated with pyrolusite and other manga- 
 nese ores, are found in the hollows of the limestone 
 beneath the gravels and brick earth forming the sur- 
 face soil. Occasionally these ores are entirely replaced 
 by phosphate of lime in similar irregular masses. 
 
 Titaniferous Iron Sands. In nearly all crystalline 
 rocks, hematite or magnetite, usually titaniferous, is 
 very commonly found, disseminated through the 
 mass in the form of fine grains or crystals. When 
 such rocks are subjected to disintegration, the ferru- 
 ginous minerals are set free and give rise to the sub- 
 stance known as black-sand, which, from its high specific 
 gravity, is easily separated by the action of water from 
 the lighter minerals quartz, felspar, &c., accompanying 
 it. One of the most familiar instances is afforded by 
 the process of alluvial gold-washing, where the first 
 operation consists in concentrating the gold in a small 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 73 
 
 rolume of black sand, which, is afterwards removed 
 cither by a magnet, or more generally by careful wash- 
 ing in a pan or batea. Along the sea-shore, especially 
 in countries where granites or other crystalline rocks 
 occur, streaks of black sand, washed out by the action of 
 the waves from the associated siliceous minerals, are very 
 commonly found upon gently sloping portions of the 
 beach ; and in some instances the quantity is so large 
 that it may be utilized as an iron ore. Among these 
 localities may be mentioned the shore of the Bay of 
 Naples, Taranaki in New Zealand, and more particu- 
 larly the whole of the north-east coast of British 
 America ; the more important deposits being situated 
 along the north shore of the St. Lawrence, from tho 
 Moisie River eastward. These sands are derived from 
 the waste of the Norite, or Labrador ite rock, which 
 forms a great part of the Upper Laurentian, or Labra- 
 dor series of the Canadian geologists, consisting of a 
 mixture of Labrador felspar, hypersthene, magnetite, 
 and titaniferous iron ore. Sometimes the latter mineral 
 is found in good- sized blocks, as, for instance, at Min- 
 gan, being obviously derived from a mass of ore. At 
 Moisie, where those sands form the beach, they are ex- 
 posed to the action of the waves which effect a process of 
 concentration so that after a prevalence of certain winds 
 great belts of nearly pure black sand are exposed along 
 the shore. When visited in 1868 by Dr. Sterry Hunt, 
 trenches were being sunk to a depth of 5 feet on the 
 shelving beach about half way between high and low 
 water marks. The sections presented alternations of 
 ntarly pure siliceous sand and of black iron-sand, the 
 latter in layers of from half an inch to 6 inches in 
 thickness, often with a small admixture of grains 
 of red garnet. The thicker layers of moist black sand 
 
 E 
 
METALLURGY OF IRON. 
 
 were easily removed by shovels from the more siliceous 
 part, and amounted by measure to about one and a half 
 or two feet of the total thickness of five feet excavated. 
 The ore was subjected to a further separation by dressing 
 on a shaking - table, about 20 feet long and 4 feet 
 wide, with a somewhat concave surface, upon which, by 
 the aid of a gentle current of water, a further portion 
 of the lighter grains, consisting chiefly of quartz, was 
 washed away, so that the ore as prepared for smelting 
 contained but 5| per cent of insoluble siliceous matter. 
 When freed entirely from the associated earthy 
 minerals, the black iron sands may be divided into a 
 magnetic and a non-magnetic portion ; the former 
 being nearly pure magnetite, while the latter is chiefly 
 titaniferous iron ore. The following analyses, by Sterry 
 Hunt, give the composition of the dressed sand smelted 
 at Moisie iron- works. 
 
 
 i. 
 
 u. 
 
 in. 
 
 Protoxide of iron 
 Titanic acid 
 Protoxide of manganese 
 Lime . . . . ' 
 Insoluble residue : : ; 
 
 85-79 
 4-15 
 0-40 
 0-90 
 1-95 
 
 56-38 
 28-95 
 1-10 
 0-95 
 8-75 
 
 70-10 
 16-00 
 
 5-92 
 
 Total . '.' V ' . '*' . 
 
 93-19 
 
 96-13 
 
 92-02 
 
 If estimated as magnetic oxide 
 
 92-68 
 
 
 
 
 
 Metallic iron .... 
 
 66-73 
 
 43-85 
 
 55-23 1 
 
 I. Magnetic portion of dressed ore ; II. Non-mag- 
 netic portion ; III. Unwashed black sand : as a whole, 
 it corresponds in composition to about equal parts of 
 I, and II. In these analyses the iron is expressed as 
 protoxide, though a portion of it occurs in a higher 
 state of oxidation, as it is difficult to determine exactly 
 the proportion of the two oxides in the presence of 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 75 
 
 titanic acid. At Mingan, Natasquan, and several other 
 points along the Labrador coast, iron sands occur under 
 generally similar conditions to those described by Dr. 
 Sterry Hunt. The siliceous portion which remains after 
 the removal of the heavier metallic grains, is found, when 
 examined under the microscope, to contain in addition to 
 quartz and garnet, cleaved fragments of felspars, which 
 often include well-formed octahedra of magnetite. 
 
 The production of cast iron from magnetic sand is 
 attended with considerable difficulty, as the fine state 
 of division of the ore renders it unfit for treatment in 
 the blast furnace. Various processes have been sug- 
 gested for overcoming this defect, the principle most 
 generally in favour being that of agglomerating the 
 sand with clay and other earthy matter, so as to form it 
 into lumps, which can then be used in the blast furnace 
 in the same way as ordinary ores. None of these pro- 
 cesses have, however, been sufficiently successful to 
 require further notice, and it is only within the last few 
 years that the black sand of the Labrador has been 
 treated to advantage, by converting it into wrought iron 
 directly in the open fire or bloomary furnace, a notice 
 of which will be found at the end of Chapter XII. 
 
 Brown Iron Ores of the Secondary Formations. In the 
 lias, oolitic, and lower greensand formations, brown 
 hematites, mostly of an impure and sandy character, 
 are found almost continuously from the northern parts 
 of Wiltshire to the wolds of Yorkshire, passing througli 
 Oxfordshire, Northamptonshire, and Lincolnshire, 
 usually appearing as a dark, ochreous, brown, oolitic 
 rock, occasionally having a greenish cast on a freshly- 
 fractured surface. The most important bed is that occur- 
 ring in the lower part of great oolite, from the neigh- 
 bourhood of Baiibury through Northamptonshire. 
 
76 
 
 METALLURGY OF IRON. 
 
 Although of low quality, the ease with which they may 
 be quarried has caused these ores to be largely wrougnt 
 for export to Staffordshire and South Wales, besides 
 being smelted in furnaces erected on the spot. In some 
 places, the Northamptonshire ore appears to be the 
 result of an alteration of an argillaceous carbonate of a 
 similar character to that worked in the North Riding of 
 Yorkshire, under the name of the Cleveland Ironstone. 
 At Westbury, in Wiltshire, the same ore is found in 
 the coral rag ; and at Seend, near Devizes ; and Lin- 
 slade, in Buckinghamshire, in the lower greensand. 
 In the last-mentioned locality there is no continuous 
 bed, but large nodular masses of brown ochreous limon- 
 ite are found scattered through about 50 or 60 feet of 
 brown sand. The nodules are often hollow, and filled 
 with loose white sand. 
 
 ANALYSES OF BROWN IRON ORES FROM THE SECONDARY 
 FORMATIONS. 
 
 
 I. 
 
 II. 
 
 III. 
 
 IV. 
 
 Peroxide of iron 
 
 44-67 
 
 64-61 
 
 67'8 
 
 52-86 
 
 Protoxide of iron 
 
 0-86 
 
 
 
 
 
 
 
 Alumina 
 
 9-10 
 
 3-85 
 
 8-5 
 
 7-39 
 
 Protoxide of man 
 
 
 
 
 
 ganese 
 
 0-44 
 
 
 
 0-7 
 
 0-51 
 
 Lime 
 
 9-29 
 
 0-64 
 
 2-8 
 
 7-46 
 
 Magnesia 
 
 0-66 
 
 0-20 
 
 0-8 
 
 0-68 
 
 Phosphoric acid 
 
 0-55 
 
 0-64 
 
 2-3 
 
 1-26 
 
 Carbonic acid 
 
 6-11 
 
 
 
 n , (Vanadic 
 1 ( acid 
 
 4-92 
 
 Silica . 
 
 12-34 
 
 18-02 
 
 7-9 
 
 13-16 
 
 Sulphur. . . 
 
 trace 
 
 
 
 A , ( Arsenic 
 0-1 I acid 
 
 0-03 
 
 Water . . . 
 
 16-31 
 
 11-85 
 
 10-3 
 
 11-37 
 
 
 100-33 
 
 99-81 
 
 101-3 
 
 99-64 
 
 Metallic iron . . 
 
 31-94 
 
 45-22 
 
 47-5 
 
 37-00 
 
 
 i 
 
 
 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 77 
 
 No. I. From the middle lias (marlatone), Fawler, near Blenheim, "by 
 
 Pick 
 
 II. Lower greensand ore, Seend, Wiltshire, by Riley. 
 III. Oolitic ore (bohnerz), White Jura, Kandern, Bavaria, by A. 
 
 Miiller. 
 IV. From the Northampton sands, in the great oolite, Welling- 
 
 borough, by Spiller. 
 
 In France red and brown, hematite occur in oolitic 
 and liassic rocks, under somewhat similar conditions to 
 those observed in this country, the most important 
 deposit being that of La Youlte, in the Ardeche, where 
 three beds of a compact earthy red hematite, varying 
 3J to 16 feet in thickness, are interstratified in marls 
 which are variously stated as belonging to the lias or 
 the Oxford clay. Oolitic varieties of the same minerals 
 are found in all three divisions of the series ; but, as a 
 rule, they are more argillaceous than the English ores 
 of the same age. 
 
 In Bavaria and Wirtemberg, the lower members of 
 the oolitic group or brown Jura formation contain 
 similar ores, on the north-west side of the Swabian Alps, 
 the maximum thickness observed being 18J feet in the 
 neighbourhood of Aalen and Wasseralfingen. Another 
 large development in the same formation in the Grand 
 Duchy of Luxembourg extends into the French por- 
 tion of the Moselle valley, and forms one of the most 
 important and productive iron districts on the continent 
 of Europe. 
 
 Besides the stratified ores above noticed, the South 
 German oolites often contain irregular masses of loose 
 concretionary brown hematite, known as bean ore 
 (bohnerz), filling cracks or funnels in the eroded 
 surfaces of limestones. These concretions vary from the 
 size of a small pea up to that of a walnut, the larger 
 being less perfectly spherical than the smaller ones. 
 
78 METALLURGY OF IRON. 
 
 The cementing material is a ferruginous sand or clay, 
 which, is sometimes sufficiently compact to form a kind 
 of breccia ; but, as a rule, it is unconsolidated, and may 
 be removed from the ore by washing, which, when pre- 
 pared for smelting, contains about 36 per cent, of iron. 
 
 Sandy brown iron ores, forming superficial deposits, 
 are worked at many places in the Wealden rocks of the 
 Boulogne district, for the supply of a large range of 
 furnaces at Marquise, between Boulogne and Calais. 
 
 Bog Iron Ore Limonitc. Although not found iu 
 this country in sufficient quantity to be worth working, 
 these ores are abundantly developed in Europe, 
 especially on the great plain of North Germany, which 
 extends from the borders of Holland to the head of the 
 Baltic. They are of very variable composition and 
 quality, and, in addition to the hydrated peroxide, often 
 contain protoxide of iron in combination with humic 
 and other organic acids, and silica. According to 
 Ehrenberg the formation of bog ores is in part due to 
 infusoria (diatomaceso), which have the power of 
 separating iron from water, and depositing it as 
 hydrated peroxide in their siliceous coverings. 
 
 In Sweden, Norway, and Finland large quantities of 
 a variety of limonite, known as lake ore (sjomalmer), 
 are obtained by dredging from the bottom of the 
 numerous lakes studding the surfaces of these countries. 
 It occurs in granular concretionary forms, varying in 
 size from that of grains of coarse gunpowder up to 
 cakes of 6 inches in diameter. The work of collecting 
 these ores is confined to the winter months, the raising 
 being effected by a perforated iron shovel fixed to the 
 end of a long pole, which is lowered through a hole abouL 
 three feet in diameter made for the purpose in the ice. 
 The ore, which occurs in layers varying from 8 to 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 
 
 70 
 
 30 inches in thickness, from 10 to 200 yards in length, 
 and from 5 to 15 yards in breadth, is continually 
 forming ; and localities that have been exhausted have 
 been known to present fresh workable deposits of 
 several inches in thickness after a lapse of twenty-six 
 years. The formation of these ores is said to be mainly 
 due to infusorial agency, the iron being derived either 
 from the oxidation of iron pyrites or silicates of pro- 
 toxide of iron, such as hornblende, pyroxene, &c., in 
 the adjacent rocks. Probably the bean ores of the 
 German oolitic rocks, which are very similar in struc- 
 ture and composition, may have been formed in like 
 manner. Bog and lake ores vary very much in com- 
 position and quality : usually, however, they contain a 
 marked quantity of phosphorus, and are best adapted 
 for foundry purposes. A variety of grey pig iron, 
 made from bog ore at Batiscan, Three Rivers, Canada, 
 is largely employed for making railway wheels, on 
 account of the facility with which it chills when cast 
 in metal moulds. 
 
 ANALYSES OF BOG AND LAKE OEES. 
 
 
 I. 
 
 IT. 
 
 III. 
 
 IV. 
 
 Peroxide of iron . 
 Protoxide of iron 
 Oxide of manganese 
 Silica , 
 
 62-59 
 8-52 
 
 66-28 
 2-70 
 
 67-59 
 
 1-45 
 7-81 
 
 77-60 
 
 0-30 
 5-40 
 
 Sand . 
 Alumina 
 Lime . 
 Magnesia 
 Phosphoric acid 
 Sulphuric acid 
 Humus (apocrenic acid) 
 Water and organic matter 
 
 11-37 
 
 1-50 
 trace 
 
 16-02 
 
 13-50 
 
 1-27 
 
 9-00 
 7-50 
 
 4-18 
 
 0-47 
 0-23 
 0-18 
 
 17-81 
 
 1-81 
 
 17-25 
 
 Metallic iron 
 
 100-00 
 
 43-82 
 
 100-25 
 48-50 
 
 99-72 
 47-32 
 
 102-36 
 54-32 
 
80 METALLURGY OF IRON. 
 
 N T oa. I., II. Bog ores from the neighbourhood of Lingen, Hanorcr, 
 
 by Sen ft. 
 
 j, III. Lake ore from Flaten, "Wermland, Sweden, by Svanberg. 
 ,, IV. Bog ore from Three Elvers, Canada. The excess in the 
 analyses is due to part of the iron existing as protoxide. 
 By Sterry Hunt. 
 
 Spathic Carbonate of Iron. This ore, though, of less 
 frequent occurrence than the various forms of peroxide, 
 appears in a few localities in Central Europe in masses 
 which, for extent and value, may be fairly paralleled 
 with the " iron mountains " of Scandinavia and North 
 America. The principal English deposits are those of 
 TVeardale, in Durham, where it occurs in lodes in the 
 carboniferous limestone associated with lead and zinc 
 ores, Perran in Cornwall, Exmoor in North Devon, 
 and Brendon Hill in Somerset. Between the two 
 last-mentioned localities the ore forms a chain of lodes 
 in the middle Devonian rocks, said to be about five 
 miles long, with a maximum thickness of V7 feet. 
 Latterly they have been worked to a considerable 
 extent for export to South Wales, where they are suc- 
 cessfully employed in the production of spiegeleisen. 
 In all cases the higher part of the lode is changed into 
 brown hematite to a considerable depth by the action 
 of atmospheric air and water. 
 
 In the Devonian rocks of the Rhine, large quantities 
 of spathic ores are found in the district of Siegen, the 
 most important deposit being that called the Stahlberg, 
 or steel mountain, near Miisen, where a nearly vertical 
 wedge-shaped lode in clay slate has been worked since 
 A.D. 1313. The greatest thickness of this mass is 
 about 65 feet, the horizontal extension about 160 yards, 
 and the height or depth, which has been proved by 
 twelve working levels driven into the hill, 260 yards. 
 The annual production is about 30,000 tons. In the 
 adjoining mine, called Schwabengrube, the same lode 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES, 81 
 
 splits up into numerous smaller ores, and carries 
 cobalt, copper, and lead ores. 
 
 In the Eastern Alps spathic iron ores are largely 
 developed in metamorphic rocks, chiefly micaceous and 
 talcose schists, and crystalline limestones of Devonian 
 or perhaps Silurian age. Near Eisenerz, in Styria, the 
 celebrated " Erzberg," or ore mountain, which rises i/> 
 a height of about 2,500 feet, apparently consists of a 
 solid mass of carbonate of iron, but is in reality only 
 covered by a capping or arch of the mineral, which 
 varies in total thickness from 200 to 600 feet, including 
 a few interstratified schistose partings. The deposit 
 lays upon, and apparently passes on either side into, 
 limestone, and is covered by a breccia of limestone 
 fragments and clay slate. The best ore, which is hard 
 crystalline, and of a brownish-yellow colour, known 
 locally as "pflinz," occurs in the lower beds. The 
 associated minerals are iron and copper pyrites, quartz, 
 carbonate of lime, and more rarely cinnabar. The 
 annual production is about 110,000 tons, more than 
 50,000,000 tons being laid open in the workings. 
 
 Of a similar character, but smaller in extent, are 
 the deposits of spathic ores in Carinthia. These are 
 situated at Hiittenberg and Lolling, north-east of 
 Klagenfurth, and include a series of lenticular beds in 
 crystalline limestone, the largest being nearly 200 feet 
 thick, containing, in addition, small quantities of heavy- 
 spar, mica, chalcedony, and occasionally arsenical 
 pyrites and scorodite. 
 
 In the Permian rocks of Thuringia a large 
 irregular mass of spathic ores has been worked in the 
 Mommel and Stahlberg mines, near Schmalkalden, for 
 more than 700 years. It is of very variable form, being 
 much disturbed by intruded granitic and porphyritic 
 veins, but is in places nearly vertical, with a breadth of 
 
 E3 
 
METALLURGY OF 
 
 500 feet, and has been followed to a depth of 300 feet 
 The known length is about a mile. 
 
 ANALYSES OF SPATHIC IRON ORES. 
 
 
 I. 
 
 IT. 
 
 in. 
 
 IV. 
 
 V. 
 
 Protoxide of iron . . . j 
 
 49-47 
 
 43-84 
 
 53-<12 
 
 55-64 
 
 47-96 
 
 Protoxide of manganese . 
 
 2 '42 
 
 12-64 
 
 3-08 
 
 2-80 
 
 9-50 
 
 Peroxide of iron 
 
 
 
 0-81 
 
 
 
 
 
 
 
 Lime 
 
 3-47 
 
 0-28 
 
 
 
 0-92 
 
 
 
 Magnesia . 
 
 3-15 
 
 3-63 
 
 5-00 
 
 1-77 
 
 3-12 
 
 Carbonic acid . 
 
 37-71 
 
 38-86 
 
 38-10 
 
 38-35 
 
 39-19 
 
 Phosphoric acid . 
 
 trace 
 
 
 
 
 
 
 
 
 
 Silica . . ' 
 
 4-93 
 
 
 
 0-06 
 
 
 
 
 
 Bisulphide of iron (if J 
 
 0-08 
 
 
 
 
 
 
 
 
 
 
 101-23 
 
 100-06 
 
 99-66 
 
 99-48 
 
 99-77 
 
 Metallic iron . 
 
 38-56 
 
 34-65 
 
 41 51 
 
 43-26 
 
 37-31 
 
 manganese 
 
 1-86 
 
 9-73 
 
 2-37 
 
 2-16 
 
 7-31 
 
 No. I. from Weardale, Durham, contains traces of lead and copper. 
 Dick. 
 
 II. Brendon Hill, Somersetshire; streaked with red he- 
 
 matite. Spiller. 
 
 III., IV. Eisenerz, Styria. Haidinger. 
 
 V. Stahlberg, Miisen. Fresenius. 
 
 Argillaceous Carbonate of Iron. This is by far the most 
 important of British iron ores, furnishing nearly two- 
 thirds of the total annual iron produce of the United 
 Kingdom. It is found either in irregular nodules, inter- 
 spersed through the clays or shales of the coal measures, 
 and in a much less degree in some of the argillaceous 
 members of the secondary and tertiary rocks, or in 
 beds of several feet in thickness, and continuous over 
 considerable areas ; in the secondary formations, more 
 especially in the lias. The former, or nodular variety, 
 consists essentially of masses of carbonate of iron of a 
 compact or earthy fracture, which, in addition to varia- 
 ble proportions of carbonates of the isomorphous bases, 
 lime, magnesia, and manganese, always contain a notable 
 
COMPOSITION AND DISTRIBUTION OF IKON OTIES. 8J> 
 
 quantity of clay. The nodules occasionally coalesce 
 into beds, which are, however, usually restricted both 
 in thickness and extent. The irregular forms are often 
 concretionary, and contain fragments of fossils, such as 
 fish, small crustaceans, freshwater shells, or the remains 
 of plants. It is very common to find the nodules 
 divided by small fissures, analogous to those produced 
 by the contraction of clay in drying, which are filled 
 up with other minerals, forming miniature lodes ; the 
 most general associates being iron and copper pyrites, 
 galena, blende, carbonate of lime, quartz, and the rare 
 substances, Millerite, or sulphide of nickel, and Hatchet- 
 tine, or mineral tallow, the two latter minerals being 
 found together in the clay ironstone of Dowlais, near 
 Merthyr Tydvil, in Glamorganshire. When freshly 
 broken the nodules are usually of a light grey, yellow? 
 or bluish tint, but become brown on exposure by the 
 superficial peroxidation of the iron. Phosphoric aci(? 
 is almost invariably present, ranging in amount from 
 0-05 to rather more than 1 per cent. 
 
 The coal-fields most abundantly supplied with these 
 ores are those of South Wales, North and South 
 Staffordshire, Shropshire, Yorkshire, and Derbyshire, 
 Scotland, and Denbighshire ; while, on the other hand, 
 scarcely any are found in the great Northumberland 
 and Durham basin, or that of Lancashire. They are 
 often worked in conjunction with coal seams in the 
 same pits either simultaneously or at different times. 
 
 The yield of ironstone measures per acre varies con- 
 siderably, on account of the great irregularity in the 
 distribution and thickness of the nodules. Thus, in 
 the Barnsley district, the Tankersley Mine, a bed of 
 shale 6 feet thick, with from 12 to 15 inches of iron- 
 stone, yields about 2,000 tons to the acre ; tl:<; Parkgate 
 
METALLURGY OF IRON. 
 
 Old Black Mine, 11 inches thick, 1,500 tons ; while the 
 Clay Wood Mine, only 5J inches thick, produces from 
 1,500 to 1,600 tons. In Derbyshire the Black Shale 
 rake of Chesterfield is the most productive measure, 
 yielding from 4,000 to 7,000 tons per acre : it consists 
 of twenty bands of nodules, varying from J to 2^J inches 
 thickness, or 28 inches in all, interspersed through a 
 total thickness of about 36 feet of shale. 
 
 ANALYSES OF CLAY IRONSTONES. 
 
 
 I. 
 
 II. 
 
 III. 
 
 IV. 
 
 V. 
 
 Protoxide of iron 
 
 86-14 
 
 47'87 
 
 39-55 
 
 44-33 
 
 44-29 
 
 Peroxide of iron 
 
 0-61 
 
 
 
 2-71 
 
 1-06 
 
 
 
 Protoxide of manganese 
 
 1-38 
 
 1-12 
 
 1-50 
 
 1-00 
 
 1-13 
 
 Alumina . 
 
 0-52 
 
 0-43 
 
 1-14 
 
 0-92 
 
 0-45 
 
 Lime 
 
 2-70 
 
 1-00 
 
 3-32 
 
 286 
 
 3-06 
 
 Magnesia . 
 
 2-05 
 
 1-27 
 
 2-85 
 
 1-97 
 
 3-73 
 
 Carbonic acid . 
 
 26-57 
 
 30-96 
 
 28-63 
 
 30-92 
 
 32-48 
 
 Phosphoric acid 
 
 0-34 
 
 0-07 
 
 1-12 
 
 0-70 
 
 0-42 
 
 Bisulphide of iron . 
 
 0-10 
 
 0-25 
 
 0-05 
 
 0-07 
 
 
 
 Water . 
 
 1-77 
 
 MS 
 
 1-75 
 
 1-30 
 
 1-45 
 
 Organic matter 
 
 2-40 
 
 0-41 
 
 1-14 
 
 0-48 
 
 0-35 
 
 Insoluble residue 
 
 25-27 
 
 15-95 
 
 15-80 
 
 14-35 
 
 13-01 
 
 
 99-85 
 
 100-51 
 
 99-56 
 
 99-96 
 
 100-37 
 
 Metallic iron . 
 
 29-12 
 
 36-56 
 
 33-20 
 
 35-61 
 
 34-72 
 
 
 
 
 
 
 
 No. I. Low Moor Black Bed, near Bradford. Insoluble residue, 
 
 chiefly clay. Spiller. 
 
 IT. Fireclay balls, Dudley, South Staffordshire. Dick. 
 III. Dale Moor Hake, Stanton, Derbyshire, contains traces of zinc 
 
 and copper. Spiller. 
 
 IV. White Flats ironstone, Shropshire. Spiller. 
 V. Lumpy Vein Mine, Dowlais, South Wales, contains, in 
 
 addition, 0-14 of potash. Eiley. 
 
 Blackband Ironstone. This term is applied to clay 
 ironstones containing carbonaceous matter. These are 
 usually of a dark brown or black colour, and often of a 
 shaly structure, resembling cannel coal. They are 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 85 
 
 very valuable ores, from trie ease and cheapness with 
 widen they may be calcined by burning in heaps with- 
 out any additional fuel, the residue yielding from 50 
 to 70 per cent, of iron. Blackband was discovered in 
 Lanarkshire by Mushet in the year 1801, and haa 
 since been worked to a very great extent, but the 
 supply is now falling off. In the "Western coal-field 
 of Scotland seven principal blackband measures are 
 known, having the following average thicknesses : 
 
 Palace Craig blackband . . 12 inches. 
 
 Airdrie ,, ... . 16 ,, 
 
 Bellside ,, 6 ,, 
 
 Kiltongue ,, . . . 8 ,, 
 
 Calderbank or Kennelburn blackband . 6 ,, 
 
 Upper slaty . 15 
 
 Lower slaty ; ?.. .8 
 
 The above thicknesses are subject to considerable 
 variation, and the same bed is rarely continuous over 
 any very large area without change of composition. 
 Thus the Airdrie blackband is found in workable 
 quantity within an area of only ten square iniles, but 
 its equivalent in the form of a thin coal covers from 
 fifty to sixty square miles. The slaty band, in like 
 manner, is represented in Linlithgowshire by the cele- 
 brated Boghead cannel coal. 
 
 The yield of blackband ironstones is at the rate of 
 2,000 tons calcined ore, equal to 1,000 tons of pig 
 iron, per acre for each foot of thickness. In North 
 Staffordshire blackband occurs in beds from 4 to 9 
 feet in thickness, and is largely exported in the cal- 
 cined form for use in the South Staffordshire furnaces. 
 In South Wales it is found in numerous small irregular 
 beds, more especially in tlie western part of the coal- 
 
86 
 
 METALLURGY OF IRON. 
 
 field. More recently similar ores have been discovered 
 in the Rhenish and Westphalian coal-fields. 
 
 In South Wales, a carbonaceous spathic ore occasion- 
 ally accompanying the coal is known as coal brass, a 
 term which is also applied to the nodules of iron 
 pyrites found under similar circumstances. It differs 
 from blackband in containing considerable quantities 
 of carbonates of lime and magnesia. 
 
 ANALYSES OF BLACKBAND IRONSTONES. 
 
 
 I. 
 
 II. 
 
 in. 
 
 IV. 
 
 Protoxide of iron 
 
 46-53 
 
 50-73 
 
 43-37 
 
 37-07 
 
 Peroxide of iron . 
 
 
 
 0-45 
 
 4-10 
 
 . 
 
 Protoxide of manganese 
 
 2-54 
 
 1-86 
 
 1-50 
 
 0-23 
 
 Alumina 
 
 0-97 
 
 0-26 
 
 6-05 
 
 
 
 Lime . 
 
 2-41 
 
 2-52 
 
 3-00 
 
 6-61 
 
 Magnesia 
 Carbonic acid 
 
 1-39 
 30-77 
 
 1-26 
 33-89 
 
 0-25 
 30-50 
 
 7-40 
 36-14 
 
 Phosphoric acid 
 
 0-69 
 
 0-73 
 
 trace 
 
 0-23 
 
 Bisulphide of iron 
 
 0-38 
 
 0-38 
 
 1-56 
 
 trace 
 
 Water . 
 
 1-47 
 
 
 
 0-58 
 
 
 
 Organic matter 
 
 10-46 
 
 6-41 
 
 6-25 
 
 9-80 
 
 Insoluble residue 
 
 2-27 
 
 0-72 
 
 2-80 
 
 2-70 
 
 
 99-88 
 
 99-21 
 
 99-96 
 
 100-18 
 
 Metallic iron 
 
 36-39 
 
 39-84 
 
 36-49 
 
 28-83 
 
 No. I. Red shag ironstone, Shelton, North Staffordshire. Dick. 
 
 II. Red Mine, Apedale, North Staffordshire. Dick. 
 
 III. Blackband, Abercarne, Monmouthshire. Rogers. 
 
 IV. Coal brass, South Wales. Price and Nicholson. 
 
 Cleveland Ironstone. It has already been stated at 
 p. 67, that the middle lias or marlstone rock bed near 
 Chipping Norton and Woodstock, in Oxfordshire, 
 assumes the form of an oolitic brown hematite, being 
 apparently the result of atmospheric action upon an 
 impure variety of protocarbonate of iron. In the 
 North Riding of Yorkshire the same bed contains an 
 ironstone, but on a larger scale than prevails further 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 87 
 
 westward. Where it is best developed, the stone has a 
 total thickness of about 20 feet, made up of various 
 interstratified bands of ore, shale, and iron pyrites, out 
 of which two principal members are distinguished as the 
 P.ictcn and Aincula seams, from the respective prevalence 
 in them of fossil shells belonging to these genera. The 
 greatest workable thickness of the bed is from 12 to 
 17 feet ; the average yield is estimated at about 20,000 
 tons per acre. The usual colour of the ore is a dull 
 bluish green, from the prevalence of a silicate of 
 protoxide of iron ; in structure it is oolitic, with nume- 
 rous interspersed fossils. At Rosedale Abbey, a dark 
 blue or black variety is found, which, although oolitic, 
 is both magnetic and polar, and appears in many 
 respects to be similar in character to the mineral known 
 as Chamoisite, worked at Chamoisin; in the "Valais. 
 
 ANALYSES OF CLEVELAND IRON ORES. 
 
 ; T - 
 
 II. 
 
 III. 
 
 IV. 
 
 Protoxide of iron 
 Peroxide of iron 
 Protoxide of manganese 
 Alumina 
 Lime . . 
 Magnesia 
 Silica . 
 Carbonic acid 
 Phosphoric acid 
 Bisulphide of iron 
 Wnter 
 
 33-17 
 
 0-50 
 3-92 
 11-90 
 4-52 
 
 28-00 
 0-48 
 
 3-65 
 13-22 
 
 43-35 
 1-20 
 
 9-88 
 0-58 
 5-35 
 7-65 
 22-96 
 3-87 
 0-09 
 5-07 
 
 100-00 
 34-54 
 
 33-85 
 32-67 
 0-69 
 3-15 
 2-86 
 1-59 
 6-95 
 10-36 
 1-41 
 0-03 
 4-60 
 
 39-92 
 3-60 
 0-95 
 7-86 
 7-44 
 3-82 
 7-12 
 22-85 
 1-86 
 0-11 
 ' 2-97 
 1-64 
 
 Insoluble residue . . . 
 Metallic iron 
 
 99-36 
 25-80 
 
 98-16 
 49-17 
 
 100-14 
 33-65 
 
 So. I. Avicula, or lower bed, Grosmont, Yorkshire. Tookoy. 
 1 i. Main seam, Eston Nab. Crowder. 
 III. Magnetic ore of Rosedale Abbey. Pattinson. 
 ,, IV. Cleveland ore ; locality not stated. Sum includes 0'27 potash.. 
 The silica exists mostly in the soluble form. The residue 
 contains visible crystals of titanic acid (anatase). Dick. 
 
88 METALLURGY OF IRON. 
 
 For the following systematic account of the locali- 
 ties where iron ores are worked in the secondary for- 
 mations in England, I am indebted to my friend Mr. 
 J. W. Judd, of the Geological Survey, who has paid 
 particular attention to the geology of these deposits. 
 
 I. MIDLAND COUNTIES. A. Marlstone rock bed. 
 This, the highest portion of the middle lias series, is 
 usually ferruginous, and in certain localities forms a 
 good ironstone. It is a bed which at times attains a 
 thickness of more than twenty feet. The ore resembles, 
 in many respects, that from the Northampton sand, 
 but is calcareous rather than siliceous. 
 
 The localities where it has been worked are as fol- 
 lows : 
 
 1. Adderbury in Oxfordshire, between Banbury and 
 Deddington : these works yielded, in 1869, 10,167 
 tons ; and a few months since they were still in active 
 operation, and in process of extension. 
 
 2. Steeple Ashton, Oxfordshire. Here the North- 
 ampton sand was raised at the surface, and the marl- 
 stone rock-bed at a depth of 30 feet, both being sent 
 away as iron ore. 
 
 3. Fawler, near Stonesfield, Oxfordshire. The rock- 
 bed was worked for several years, but lately, the work- 
 ings have been stopped, owing to the great depth of 
 bearing or cover that has to be stripped to get at the 
 ore. 
 
 B. Northampton Sand. The beds worked in this 
 formation belong to the lowest portion of the Inferior 
 Oolite (zone of Ammonites murc/iisonics), and are the 
 equivalent of the Dogger of Yorkshire. The ferrugi- 
 nous beds usually form the base of the formation, and 
 rest directly on the Upper Lias clay. The good ore 
 
COMPOSI1ION AND DISTRIBUTION OF IRON OHES. 89 
 
 seldom exceeds from 8 to 10 feet in thickness. It is a 
 siliceous brown hematite, usually of poor quality, but 
 useful on account of the low price at which it can be 
 raised, as a mixture for the more expensive clay-band 
 ironstones of the coal measures. 
 
 The Northampton sand is dug for iron ore at Blis- 
 worth, Duston, Wellingborough, Irthlingborough, 
 Coggenhoe, Glendon, Finedon, Gay ton, Brixworth, 
 Woodford, Islip, Slipton, Desborough, and Stow, in 
 Northamptonshire ; Steeple Ashton and Heyford, in 
 Oxfordshire ; and Neville Holt, in Leicestershire. The 
 annual yield of the different workings cannot be less 
 than 700,000 tons. The greater part of the ore is sent 
 away to South Wales, Derbyshire, and South Stafford- 
 shire, but a large amount is also smelted on the spot at 
 Wellingborough, Irthlingborough, Glendon, and Hey- 
 ford. 
 
 Cinder heaps and other evidence of old iron work- 
 ings, abound almost everywhere on the Northampton 
 sand. Near Oundle, and at Duston, Roman remains 
 have been found in association with the cinder heaps. 
 
 There is historical evidence that in Norman times, 
 iron was made extensively all over Rockingham forest; 
 and Rockingham Castle is said to have been originally 
 erected for the defence of these furnaces, more pro- 
 bably to control the iron workers. 
 
 Besides the localities noticed above, the North am p 
 ton sand covers large areas in Oxfordshire, Northamp- 
 tonshire, Leicestershire, Rutlandshire, and Lincoln- 
 shire, which would yield immense supplies of ore if 
 opened up by railways. 
 
 II. LINCOLNSHIRE. A. Lower Lias. These beds form 
 the top of the series known as the Lower Lias lime- 
 
90 
 
 METALLURGY OF IRON. 
 
 stone and sliale, and are characterized by the great 
 abundance of Gryph&a arcuaia. The ironstone bed, 
 27 feet thick, is dug at Scunthorpe and Frodingham in 
 North Lincolnshire. In 1869 220,524 tons of ore 
 were raised, while 33,786 tons of pig iron were made 
 in six blast furnaces on the spot. Originally the iron- 
 stone smelted at this point was collected in the form of 
 rolled fragments from the alluvium, and it was only on 
 removing the cover that the thick bed now worked was 
 discovered. 
 
 B. Middle Lias. Two beds of ironstone, the upper 
 one measuring 8 feet and the lower 4 feet in thickness, 
 are met with in North Lincolnshire. They are pro- 
 bably the equivalent of some of the Cleveland iron- 
 stones. As far as is known, they are not used at 
 present. Ironstone probably of this age was formerly 
 worked at Kirton in Lindsey, also it has been found at 
 a point N."W~. of the city of Lincoln, and attempts 
 made to get a railway for the convenience of working 
 it. The marlstone rock in places forms a good iron- 
 stone in South Lincolnshire, and there is evidence of 
 its having been worked in ancient times. 
 
 0. Northampton Sand. Inferior Oolite. This was 
 extensively worked in olden times in South Lincoln- 
 shire, but at present no workings are carried oil in this 
 formation anywhere within the boundaries of the 
 county. 
 
 D. " IRONSTONE JUNCTION BED " at the base of the 
 " upper estuarine series," the equivalent of the Stones- 
 field slate of the south of England. This is a band of 
 good ironstone, and although not more than a foot in 
 thickness, was often worked in ancient times, 
 
 E. " Ironstone balls of the GREAT OOLITE CLAY/'* 
 
 A few years ago a considerable quantity of ore was 
 
COMPOSITION AND DISTRIBUTION OF IRON OIIES. 91 
 
 raised from this formation, which is the equivalent of 
 the Forest marble of the south of England, at Overton 
 near Peterborough : but the workings have been aban- 
 doned on account of the large amount of waste material 
 requiring to be removed. Similar ironstone balls of 
 good quality are frequent in the lower part of the 
 middle and upper part of the Lower Lias, but they 
 have not as yet been turned to account. 
 
 F. Neocomian. In the beds of the " Tealby series " 
 or Middle Neocomian, is found a brown ironstone 
 made up of oolitic grains exactly similar to that of 
 Steinlahde and Osterholz, near Salzgitter, in Hanover, 
 which is of the same geological age. This useful bed 
 of ore, averaging 6i feet in thickness, is full of fossils, 
 and highly calcareous, yielding from 28 to 33 per cent. 
 of iron. It is highly valued for mixing with certain 
 of the clay ironstones of Yorkshire, and is exported 
 to that district at the rate of 100 tons daily. 
 
 III. Yorkshire. In the moorland district of York- 
 shire the lower oolites, as well as the lias, contain great 
 deposits of ironstone, the following being the principal 
 horizons in descending order : 
 
 A. Upper Sandstone Shale and Coal of Phillips, 
 probably of the age of the great oolite. This group con- 
 tains numerous bands of ironstone in nodules, some of 
 which were worked in ancient times. 
 
 B. Lower Sandstone Shale and Coal of Phillips, 
 equivalent to the upper part of the inferior oolite. It 
 contains similar nodules to those in the upper series. 
 
 C. " Dogger" This includes the lower part of the 
 inferior oolite and the sands below it, or " Lias sand " 
 of Dr. Wright. In Rosedale the lower part of this 
 deposit forms a rich iron ore, often yielding as much as 
 50 per cent, of iron. It has the green or blue coloui 
 
92 
 
 METALLURGY OF IRON. 
 
 and structure of the Northampton sand. 
 
 D. Middle Lias. This formation yields the Cleve- 
 land ironstone, which is divided into several beds, 
 separated by shale. The total thickness of ironstone 
 rock varies from 8 feet, or less, to 20 feet, and the 
 yield per acre from 20,000 to 50,000 tons. 
 
 The following is the return of the amount of iron 
 ore raised and consumed in the United Kingdom foi 
 the year 1888. 
 
 Districts. 
 
 Ores. 
 
 Tons. 
 
 Devon 
 
 Red and brown 
 
 2,085 
 
 Somersetshire 
 
 Brown 
 
 1,388 
 
 Gloucestershire 
 
 ,, . 
 
 70,201 
 
 Wilts . . \ 
 Rutland . . / 
 
 Oolitic . 
 
 107,867 
 
 Northamptonshire 
 
 
 
 1,066,746 
 
 Lincolnshire 
 
 !_ 
 
 1,345,001 
 
 
 
 535,831 
 
 English coalfields 
 
 ( Clay, blar>k band, | 
 \ and brown j 
 
 1,912,390 
 
 Lancashire 
 
 Red 
 
 1,106,013 
 
 
 
 1,573,814 
 
 Cleveland .... 
 
 Liassic . 
 
 5,395,942 
 
 Durham. .... 
 
 Spat I dc and brown . 
 
 47,203 
 
 Wal^s and Monmouth 
 
 Clay and brown 
 
 105,317 
 
 Scotland .... 
 
 Cluy and black band 
 
 1,238,597 
 
 Ireland .... 
 
 Brown aluminous . 
 
 129,305 
 
 Isle of Man 
 
 Brown 
 
 16 
 
 Total of native ores 
 
 14,637,816 
 
 British ores exported 
 
 9,730 
 
 
 14,628,086 
 
 Foreign ores imported . 
 
 3,520,000 
 
 Burnt pyrites, or " Purple ore " . 
 
 464,207 
 
 Total Available Supply . 
 
 18,612,293 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 93 
 
 European Oolitic Ores. In Luxemburg, German Lor- 
 raine, and North-Eastern France oolitic iron ores, locally 
 known as minette, and similar to those of Northamp- 
 tonshire and Lincolnshire, are found in strata which 
 are variously classified either as the uppermost lias or 
 the lowest members of the inferior oolites, or brown 
 Jura series. The maximum development is in the 
 northern part of the district at Esch, in Luxemburg, 
 where there are three principal beds of ore, each 
 averaging from 10 to 12 feet in thickness, included in 
 about 82 feet of limestones. The lowest or grey bed lies 
 directly upon the upper lias sandstone, the second or 
 red bed is about 33 feet higher in the series, and about 
 40 feet higher is the third or sandy red bed. The 
 thickness of the entire formation as well as of the ore 
 beds diminishes to the southward, being only 10 to 13 
 feet near Metz with 5 feet of ore. On the French 
 side the principal workings are in the vicinity of 
 Longwy. The ore is made up of oolitic grains of limon- 
 ite, often much mixed with nodules of limestone. The 
 composition of the different beds is seen in the following 
 analyses : 
 
 A Black bed . . Kollingen, Luxemburg. 
 
 B Grey bed . . Belvaux, 
 
 C Red bed . . Russingen, 
 
 D Sandy bed. 
 
 Iron, peroxide . 
 Alumina . . . 
 Silica 
 
 Limo . . 
 
 Magnesia . 
 Phosphoric Acid 
 Sulphuric Acid . 
 Carbonic Acid . . 
 Loss on ignition 
 
 99-98 99-99 100-03 100-93 
 
 Metallic Iron . 38-51 43-60 28-10 30-56 
 
4: METALLURGY OF IRON. 
 
 These ores, besides being of similar composition, in 
 regard to economic importance bear much the same 
 relation to the iron trade in Western Germany, Belgium, 
 and Eastern France, that those of Cleveland and North- 
 amptonshire do in England. The production of minette 
 
 was in : 
 
 1878. 1888. 
 
 In German Lorraine . 822,360 tons 2,805,300 tons 
 
 Luxemburg . . 1,411,218 3,261,900 
 
 2,233,578 6,067,200 
 
 1887. 
 In France . . 2,182,000 
 
 or about 42 per cent, of the total production of Germany, 
 and 85 per cent, of that of France. 
 
 Jager has computed the estimated contents of the 
 unwrought portions of the deposit : 
 
 In Lorraine . . 2,100,000,000 tons 
 Luxemburg . . 290,850,000 
 
 the former quantity being sufficient to supply the 
 demand of the Prussian steel works at the present rate 
 of production for nearly 1,000 years. 
 
 Spanish and African Ores. The enormous increase in 
 the production of steel during the last decade has 
 created a great demand for the purer classes of iron 
 ore as well as for those containing manganese, and 
 several new and important sources of supply have been 
 developed in consequence. First in importance are the 
 mines in the neighbourhood of Bilbao, which form 
 three groups, those of Sommorostro, Galdames, and 
 Ollargon. The first of these is contained in an oval 
 area, 2J miles long and J mile broad, in the hill called 
 Monte Triano, where the ore forms a bed included 
 between sandstones and limestones of the upper creta- 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 95 
 
 ceous (Senonian) period. The ores are of three kinds, 
 distinguished as A. Campanil, B. Vena dulce, and C. 
 Paibio, whose average composition is as follows : 
 
 
 A 
 
 B 
 
 C 
 
 Fe 2 3 . 
 
 80-800 
 
 90-500 
 
 77-85 
 
 MnO . 
 
 1-132 
 
 1-200 
 
 
 
 CaO 
 
 2-482 
 
 0-634 
 
 0-50 
 
 MgO . 
 APO 3 .:<<;< . 
 
 traces 
 
 traces 
 
 traces 
 1-50 
 
 SiO 3 -;" >. 
 
 5-550 
 
 1-880 
 
 8-50 
 
 CO 2 
 
 ) 
 
 
 
 Organic matter 
 Loss on ignition . 
 
 V 8-981 
 
 | 5-800 
 
 10-60 
 
 98-945 100-14 100-05 
 
 Metallic Iron 57'75 62-44 54-50 
 
 The Campanil ore is red both in mass and powder, 
 moderately hard, and associated with calcite. It forms 
 the upper part of the bed., and from its structure 
 appears to be an altered spathic ore ; in depth it passes 
 into the richer and softer vena dulce. Both kinds are 
 called red hematite, but they are not improbably 
 turgite, judging from the amount of volatile matter 
 shown in the analysis. The Eubio ore is a limonite of 
 spongy or mamillated structure, found along the out- 
 crop of the schistose sandstones, which contain altered 
 nodules of carbonate of iron. The actual thickness of 
 the main bed has not been proved, but it is known to 
 be more than 220 feet. The Eubio ore forms an escarp- 
 ment that rises to the height of 300 feet. These ores, 
 which have been worked from time immemorial in the 
 forges producing the famous Biscayan iron, are noted 
 for their extreme purity and easy reductibility, the 
 
96 METALLURGY OF IRON. 
 
 latter property fitting them for treatment by the 
 Chenot process (see page 289) ; but it is only within 
 the last six or eight years that the importance of 
 the district has been fully realised, and at the present 
 time it is of nearly equal rank with Cleveland and 
 the N.W. of England as a source of production, almost 
 all the great ironworks in Europe being interested in 
 mining its ores ; and the output has increased from 
 1,305,656 tons in 1878, to 4,400,000 tons in 1887, which 
 was distributed in the following manner : 
 
 1878. 1887. 
 
 Tons. Tons. 
 
 To England . . 856,038 2,374,674 
 
 Holland* . . 104,685 707,394 
 
 Scotland . . 47,445 480,993 
 
 France . . . 150,799 356,980 
 
 United States . 5,840 152,077 
 
 Belgium . . 59,943 98,304 
 
 Spain . . . 30,525 28,274 
 
 1,255,255 4,188,696 
 
 Algerian Iron Ores. One of the most valuable iron 
 mines in the world is that of Mokta el Hadid, situated 
 about twenty miles from Bona, in East Algeria. It 
 originally formed a cliff about 400 feet high, and was 
 worked as an open quarry in terraces 16 feet high, 
 nineteen of these terraces being required to reach the 
 top of the hill. The greatest thickness measured hori- 
 zontally is about 105 feet ; but from the central point 
 it diminishes along the outcrop, and also when worked 
 underground, where it is 28 feet thick, A second 
 smaller bed of 13 feet has been found by boring at a 
 
 * For Rhenish and Westphalian works. 
 
COMPOSITION AND DISTRIBUTION OP IRON ORES. 97 
 
 higher level between the schist forming the roof of the 
 main deposit and an overlying bed of limestone. A 
 certain proportion of the ore is brownish-red and soft, 
 and can be worked with the pick ; but the bulk of it, 
 the so-called blue or black ore, is very dense hematite 
 and magnetite, and must be blasted with gunpowder. 
 
 In the central province, that of Algiers proper, 
 spathic iron ores are found in veins in cretaceous rocks, 
 but for the most part associated with lead and copper 
 ores, for which they are alone worked. 
 
 In the western province of Oran another class of de- 
 posits are found which are of considerable importance. 
 These are hematites very intimately associated with 
 limestone of probably liassic age. The ore varies con- 
 siderably in quality, is more or less manganiferous, and 
 tolerably hard. Occasionally masses of limestone per- 
 fectly unchanged are found included in the ore bodies. 
 According to Pouyanne, their origin is to be attributed 
 to the action of mineral springs. A second class of 
 deposits, found in miocene strata, consists of lenticular 
 masses of hematite, which are considered as derived 
 from the waste of those of the first class. The largest 
 and most important mines are those of Camerata, 
 Soumah, and Benisaf ; the latter is about sixty miles 
 west of Oran, and produces a soft calcareous hematite, 
 very like that of Bilbao. A new harbour has been 
 built at Benisaf for the shipment of these minerals, 
 which under the name of Tafna ores are exported to all 
 the principal iron works of the world. 
 
 The average composition of Algerian ores, smelted 
 by the Terre-Noire Company in 1878, was as follows: 
 
 ABC 
 
 Iron (Metallic) 58-00 65-85 58-00 
 
 Manganese 2-20 1-08 2-52 
 
98 METALLURGY OF IRON. 
 
 ABC 
 
 Silica . . . 8-00 2'00 3-00 
 
 Lime . . . 3-00 
 
 Alumina . . 0'48 traces traces 
 
 Sulphur . .' 0-12 
 
 Phosphorus . . traces traces 0*12 
 
 A., B., Mokta magnetic ores ; 0., Tafna red ore. 
 
 In 1874 Mokta shipped 430,000 tons, being the 
 largest output realised to that year ; and in 1887 
 153,693 tons. In 1880 Tafna produced 204,000 tons ; 
 and 272,354 tons in 1887. 
 
 Iron Ores of India. The peninsula of India is in 
 the distribution of its iron ores very similarly circum- 
 stanced to that of Scandinavia ; that is to say, we have 
 in both large tracts of country occupied by crystalline 
 rocks of ancient date containing rich and pure ores, 
 while those in the succeeding sedimentary formations 
 are comparatively lean and of inferior quality. The 
 former class are best developed in the neighbourhood 
 of Salem, in the Madras presidency, where dense and 
 rich magnetic ore was for some years raised and 
 smelted by the East India Iron Company, the pig 
 metal produced being mostly exported to England. 
 Similar ores found in the southern highlands of Bengal, 
 in the district of Palamow, in the upper valley of the 
 Sone River, are of extreme purity, but the deposits are 
 not large. At Lohara and Pipalgaon, near Chanda, 
 in the Central provinces, a very dense specular and 
 magnetic ore is found interstratified with crystalline 
 schists in masses that are comparable as regards size with 
 those of Algeria and Lake Superior. In the strata 
 b alow the coal measures of Chanda a bed of sandstone 
 
COMPOSITION AND DISTRIBUTION OF IRON ORES. 99 
 
 is found containing angular fragments of hematite 
 and specular schist, evidently derived from similar 
 deposits to those last mentioned. At Tendukahra, near 
 the Nerbudda Coal and Iron Company's mines, a man- 
 ganiferous brown hematite, apparently interstratified in 
 limestone, is worked by the native smelters on a com- 
 paratively large scale. This is, perhaps, the best iron 
 ore as regards working quality found in India. 
 
 In the coal-field of Eanigunge the upper and lower 
 coal-bearing series are separated by about 1,400 feet of 
 shales containing nodules of ironstone, often in con- 
 siderable quantity. These, so far as they have been 
 worked, are argillaceous brown ores, often containing 
 fossil plants, but in depth they will probably turn into 
 carbonates or clay ironstones proper. As regards 
 quality they are very inferior, yielding a pig metal 
 with from 1 to 2 per cent, of phosphorus. They 
 were smelted for some time at Barakur by the Bengal 
 Iron Company, who produced 12,700 tons of pig iron 
 during the short time that their furnaces were in 
 operation. 
 
 Superficial limonite, locally known as laterite, 
 is very common throughout the peninsula, and is 
 used in the native furnaces in many places. Attempts 
 have also been made to smelt it in blast fur- 
 naces in Beerbhorm, in Bengal, and on a larger scale at 
 Deechourie and Kaledongee, in the Terai or forest- belt 
 of the Himalayas, in Kumaon ; but in both cases the 
 attempts have proved unfortunate, the localities having 
 been selected without a proper preliminary investiga- 
 tion as to the quality and quantity of ore available. 
 
 Iron Ores of the United States. The most important 
 deposits within the territory of the United States are 
 grouped by Newbery according to age and position, as 
 follows : 
 
t 
 
 100 METALLURGY OF IRCKN, 
 
 1 . Lauren tian Magnetites of the Alleghany belt and 
 the Adirondacks. These are best developed in 
 northern and eastern New York, northern New Jersey, 
 and the western part of North Carolina, and occur in 
 lenticular masses varying in thickness from u few 
 inches to a hundred feet and upwards, which are con- 
 tained in gneiss, crystalline schists, and limestones, and 
 are as a rule very much contorted and disturbed. The 
 chief centres of production are on Lake Chanplain, 
 and in Clinton and Orange Counties, New York, and 
 the adjoining northern part of New Jersey, and on 
 the highlands immediately north and west of the 
 city of New York. The ores are chiefly hard mag- 
 netites, with from 50 to 60 per cent, of iron, and 
 moderately free from phosphorus except when con- 
 taining visible masses of apatite, sometimes titaniferous, 
 and almost without any manganese. 
 
 2. Huronian Ores of Lake Superior and Missouri. 
 The general characteristics of these ores have been 
 already noticed at page 65, but since that account was 
 written the district has been very largely developed 
 and the structure of the deposit has been minutely 
 studied by the state geologists, notably by Brookes and 
 Pumpelly. The following analyses, averaged from a 
 very large number, represents the three principal classes 
 of ore produced : 
 
 ABC 
 
 Protoxide of Iron . 19-64 
 
 Peroxide of Iron . 90-52 67-76 75-75 
 
 Protoxide of Manganese trace:; 0-13 0-80 
 
 Alumina . . 1-39 2-13 1-54 
 
 Lime . . . 0-70 0-68 0-36 
 
 Magnesia . . 0-42 0-69 0-29 
 
 Sulphur . , , 0-05 0-13 0-11 
 
COMPOSITION AND DISTRIBUTION OF IIION ORES. 101 
 
 ABC 
 
 Phosphoric acid . 0-26 0-20 0-19 
 
 Silica (and insoluble) 5-89 7'83 14-06 
 
 Water, combined ) t 3-94 
 
 hygroscopic / j 1-18 
 
 Volatile matters . 1-81 
 
 100-00 100-00 100-00 
 
 Metallic Iron . . 62-92 62-93 52-65 
 
 Phosphorus . . 0-11 0-085 0-078 
 
 A., hard red ore ; B., magnetic ore ; 0., soft hematite. 
 
 Besides these a fourth class or second equality of red 
 ore, with about 50 per cent, of iron and 28 per cent, of 
 silica, is produced to a small extent. The total produc- 
 tion of this district in 1888 was 5,023,279 tons, or 40 
 per cent, of the total of that of the United States. 
 
 The two great ore deposits of Missouri are contained 
 in crystalline rocks ; that of Iron Mountain is a large 
 vein in porphyry, while Pilot Knob is made up of alter- 
 nations of porphyry and specular hematite, which are 
 apparently stratified and dip at a low angle. The ore 
 bed, which is about 40 feet thick, is divided by a bed 
 of slate, the lower half being the most valuable. The 
 Missouri ores are very similar in character to those of 
 Lake Superior, and contain about the same amount 
 of iron and phosphorus, 60 to 65, and 0-3 to 0-11 
 per cent, respectively. The output in Missouri was 
 160,000 tons in 1888, of which about 70 per cent, was 
 contributed by Iron Mountain and the remainder by 
 Pilot Knob. 
 
 The Cornwall Ore Bank, in Eastern Pennsylvania, 
 is another example of a magnetic ore alternating in 
 horizontal beds with crystalline rocks, which in this 
 case are serpentinous or chloritic (probably analogous 
 to the Taberg in Sweden). It contains about 50 per 
 
102 METALLURGY OF IRON. 
 
 cent, of iron and is practically free from phosphorus. 
 This, the largest iron mine in America, produced 
 280,000 tons in 1880, and 722,921 tons in 1888. 
 Other important deposits of magnetic ore have been 
 described by Newbery as occurring in beds in granite 
 in Southern Utah, probably of lower Silurian age. 
 
 3. The Clinton Ores. This is an oolitic or granular 
 calcareous hematite which follows the outcrop of the 
 Clinton group on the upper Silurian series from Wiscon- 
 sin to Georgia, in anearly continuous line for 1,500 miles, 
 forming one or more beds from 3 to 12 feet in thickness. 
 In character the ore varies from an aggregate of loose 
 flattened grains to a highly ferruginous sandstone ; the 
 former is known as flaxseed, and the latter as dyestone 
 ore. Another general name is fossil ore, as the grains 
 are concreted round fragments of shells, or crinoids. It 
 is considered to be an old lake deposit formed like the 
 concretionary limonites of Sweden, and its organic 
 origin to be further evidenced by its uniformly contain- 
 ing a large amount of phosphorus. These ores are chiefly 
 worked in the Southern States, and from their position 
 can be worked very cheaply. They average from 45 to 
 55 per cent, of iron, and J to 2 per cent, of phosphorus. 
 
 4. Coal Measure Ores. Nodular carbonates and black 
 band ores are comparatively rare, being mainly con- 
 fined to the coal-fields in Ohio and Kentucky. 
 
 5. Limonites. In the hollows of the Silurian and 
 carboniferous limestones of the eastern flank of the 
 Alleghanies, brown iron ores are found in considerable 
 quantity, in irregular lenticular masses. 
 
 The production of iron ores in America in 1880 was 
 7,971,706 tons, of which Pennsylvania contributed 
 27-4, Michigan 23, New York 15-83, and New Jersey 
 95 per cent. In 1888 it was about 10,166,000 tons. 
 
ASSAY AND ANALYSIS OF IRON ORES, 103 
 
 CHAPTER IY. 
 
 ASSAY AND ANALYSIS OF IRON ORES. 
 
 IN order to arrive at trie economic value of an iron ore, 
 it is requisite to determine not only its percentage con- 
 tents of metallic iron, but the approximate constitution 
 of the associated earthy matters with regard to their fusi- 
 bility, and also the amount of elements likely to exert a 
 special influence on the iron produced, such as sulphur, 
 phosphorus, &c., which as a rule are present only in a 
 small quantity. For the latter purpose it is necessary to 
 make use of the ordinary processes of quantitative 
 chemical analysis, while the two former questions may 
 be answered by means of the dry assay, which repro- 
 duces in miniature the operations performed on the 
 great scale in the blast furnace, giving as a result the 
 maximum amount of cast iron to be obtained for the 
 ore under the most favourable conditions. 
 
 If it is desired to know the amount of pure iron 
 present, recourse must be had to the wet way, either by 
 direct determination as peroxide, or indirectly by the 
 volumetric method, in which the amount of metal is 
 deduced from the number of measures of solution of 
 an oxidising agent of a given strength necessary to 
 convert the amount of protochloride of iron contained 
 in the sample dissolved in hydrochloric acid into per- 
 chloride. This latter method is in many respects 
 preferable to the former, and may be used with advan- 
 tage not only in assaying, but also in the complete 
 analysis. 
 
 The method of conducting these operations will next 
 be briefly noticed under the following heads : 
 
104 METALLURGY OF IRON. 
 
 1. Dry Assay. 
 
 2. Wet Assay. 
 
 3. Analysis. 
 
 Dry Assay. The ore in a finely divided state, mixed 
 with charcoal and appropriate fluxes, is exposed in a 
 crucible to a full white heat in a wind furnace or 
 forge. The reduced iron combines with a portion of 
 carbon, forming cast iron, while the earthy matters of 
 the fluxes are properly adjusted to give a fusible slag. 
 
 The following method is recommended by Berthier 
 to be used in the preliminary determination of the 
 earthy matters : 
 
 A weighed quantity (about 150 grains) of the ore is 
 to be heated to redness in a porcelain crucible ; the 
 loss of weight gives the amount of water, carbonic 
 acid, and other volatile matters. Another weighed 
 quantity, in fine powder, is heated with very weak 
 nitric acid, which dissolves out the carbonates of lime 
 and magnesia ; the residue, after filtration, is weighed, 
 and contains only oxide of iron, clay, and quartz, the 
 difference giving the amount of the earthy carbonates. 
 
 Lastly, another portion of ore is digested in strong 
 hydrochloric acid, whereby the carbonates of lime and 
 magnesia and the oxides of iron are dissolved, while the 
 insoluble residue consists of quartz and clay. This is 
 weighed, and the oxides of iron are determined by the 
 difference of weight after deducting that of the car- 
 bonates of lime and magnesia previously found. If 
 it is desired further to determine the amount of quartz, 
 the residue of the last operation, fused with three 
 dmes its weight of a mixture consisting of equal 
 parts of carbonates of soda and potash, evaporated to 
 dryness with hydrochloric acid and digested with 
 water, whereby the silica is rendered insoluble, and 
 
ASSAY AND ANALYSIS OF IRON ORES. 105 
 
 may be collected on a filter, dried, ignited, and weighed, 
 the difference between it and the weight of the total 
 insoluble residue, gives approximately the amount of 
 alumina. 
 
 From the results obtained by the preliminary inves- 
 tigation, the proportion of fluxes necessary to be added 
 can be calculated, the object being to produce an easily 
 fusible slag. The following are good types of such 
 
 2 (2 CaO. SiO 2 ) + 2 APO 3 3 SiO 2 , with 47 lime, 15 alumina, and 37 
 silica per cent. 
 
 CaO SiO 2 -{- APO 3 3 SiO 2 , with 30 lime, 14 alumina, and 56 silica per 
 cent. 
 
 The first approximates in composition to the average 
 slag of a coke furnace ; while the second, in like man- 
 ner, represents that from a charcoal furnace in good 
 working order. 
 
 The following are the principal fluxes required : 
 1. Silica in the form of white glass-house sand or 
 ground flints, which are practically free from iron : the 
 purest variety is that obtained by crushing and grind- 
 ing rock crystal, which has been previously shivered 
 by quenching in water from a red heat, but this pro- 
 cess is troublesome and unnecessary. 2. Alumina : 
 this is best supplied in the form of china clay, which 
 contains about 40 per cent, of alumina, 47 of silica, and 
 13 of water. Before using it must be dried at a strong 
 heat and finely powdered. Fire clay and shale are also 
 used, but have the disadvantage of containing small 
 quantities of iron. 3. Lime, either in the caustic 
 state, or as carbonate ; the latter is more convenient, 
 either statuary marble, chalk, or any limestone free 
 from iron may be used. It may in some instances be 
 advantageously replaced by fluorspar, which forms a 
 
106 METALLURGY OF IRON. 
 
 good slag, but is rarely used on the large scale in the 
 smelting process. Plate or crown glass free from lead 
 may be substituted for sand with argillaceous ores : it 
 contains from 60 to 70 per cent, of silica, the remainder 
 being lime, potash, and soda. Borax, on account of its 
 great solvent powers, is not to be recommended, as 
 it is liable to take up a portion of the iron which 
 escapes reduction, causing a loss on the assay. Clean 
 blast-furnace slags, such as are obtained from a furnace 
 on grey iron, if carefully freed from any entangled 
 shots of metal, may be used with advantage in fluxing 
 rich ores containing but little foreign matters. The 
 best slag for argillaceous ores is that resulting from a 
 mixture of carbonate of lime equal to two-thirds of the 
 total amount of clay present. 
 
 Although Berthier's method of approximately deter- 
 mining the composition of the ore previous to the 
 assay may in certain cases be advantageous, it is not 
 generally advisable to adopt it, as a sufficiently good idea 
 of the nature of the fluxes to be added may usually be 
 formed from the appearances of the ores alone. Thus, 
 hematites, both red and brown, are generally associated 
 with silica, and require both lime and alumina. Spathic 
 and other calcareous ores not containing clay require 
 an addition of silica in the form of sand, or an acid 
 silicate such as glass, besides lime and alumina, while 
 argillaceous carbonates may be fluxed with lime alone. 
 In Sweden, magnetic ores are usually assayed with 
 reference to their self-fluxing powers, those varieties that 
 contain a sufficiency of readily fusible earthy minerals, 
 such as garnet, idocrase, pyroxene, &c., to form their 
 own slags, being of greater value than those requiring 
 the addition of fluxes. 
 
 The proper apportionment of fluxes may also be formed 
 
ASSAY AND ANALYSIS OF IBON ORES. 1Q7 
 
 by the method of trial and error, three or four equal 
 weights of the ore being treated at the same time in 
 the furnace with variable additions, according to the 
 following list : 
 
 I. II. III. IV. V. 
 
 Silica . .50 50 30 45 15 
 
 Alumina . .25 16 20 18 5 
 
 Lime . . ,25 34 50 37 80 
 
 The weight in all cases to be made up to one-half 
 of that of the quantity of ore employed. The most 
 advantageous proportion will of course be that giving 
 the highest produce. 
 
 The following proportions of fluxes are recommended 
 by Plattner : 
 
 I. II. III. IV. V. 
 
 Lime ... 10 5 25 20 
 Fluorspar . . 25 25 25 20 20 
 Clay ... 10 
 
 No. I. is for use with magnetite ; II. with specular 
 iron ore ; III. with earthy and siliceous red and brown 
 hematite, clay iron ore, and limonite ; IV. with brown 
 hematite and forge cinders ; and Y. with spathic ore. 
 
 Mode of Conducting the Assay. This may be per- 
 formed either in plain clay crucibles, or in such as 
 have been lined with charcoal or bmsqued. In the 
 former case, from 100 to 150 grains of finely- powdered 
 ore are intimately mixed with the appropriate fiuxes 
 and about 25 per cent, of charcoal powder, and charged 
 into a blackleaa or clay crucible, the cover being luted 
 on with clay. It is then placed in a wind furnace, 
 and subjected to a moderate heat for a short time, in 
 order to drive off any water and carbonic acid that 
 may be present, after which the fire is increased and 
 maintained at a full white heat for an hour. Wher 
 the fuel has burnt down, the crucible is taken out and 
 
108 METALLURGY OF IRON. 
 
 allowed to cool. It is then broken, and if the opera* 
 tion has been properly conducted, a button of grey 
 cast iron, smooth and well melted, will be found at the 
 bottom, surmounted by a well-melted glassy or enamel- 
 like slag. It is, however, necessary to reduce the slag 
 to powder and examine it with a magnet for shots of 
 metal, which are to be added to the principal button 
 and weighed with it. If the fluxes have been impro- 
 perly proportioned, the slag will be only imperfectly 
 melted, and the assay must be repeated. 
 
 The use of brasqued crucibles is generally pre- 
 ferable to the foregoing method. They are prepared 
 as follows : The hollow of the crucible is filled 
 with charcoal powder rammed down hard, and ren- 
 dered adhesive by a slight admixture of treacle or 
 starch. When dry, the cement is carbonised by heat- 
 ing to redness in a covered vessel, and a compact 
 smooth mass of charcoal is obtained, exactly filling the 
 crucible. A cylindrical cavity, of sufficient size to con- 
 tain the mixture of flux and ore, is bored out with a 
 spatula, and the sides are polished by rubbing with a 
 glass rod. After the introduction of the assay the hole 
 is stopped with a charcoal plug, and the cover of the 
 crucible is luted on as before described. The weight of 
 samples operated upon may be, as in the former case, 
 from 100 to 150 grains. 
 
 A more convenient method of conducting the assay 
 is that adopted in Sweden, where small brasqued cruci- 
 bles, about 2 inches high and 1 J inches in diameter, 
 are used. The weight of ore taken being only 10 or 
 15 grains, four crucibles are placed in the furnace at 
 one time, a piece of fire brick about 3 inches square 
 being used as a stand : coke or anthracite may be most 
 conveniently used as fuel. As soon as a white heat has been 
 
ASSAY AND ANALYSIS OF IRON ORES. 1Q9 
 
 attained, the fire is allowed to go down, and the cruci- 
 bles are removed by lifting out the stand, to which they 
 are generally cemented by the slag of the fuel when 
 sufficiently cool. When cold they are broken, and the 
 buttons of metal and slag found in the cavity of the 
 brasque are removed and separated, the latter are 
 crushed in a steel mortar, and any further portions of 
 iron that they may contain are extracted by the magnet 
 in the usual way. 
 
 When the assays are well done the four results 
 should not vary from each other more than two or 
 three-tenths per cent. 
 
 The following conclusions may be deduced from the 
 appearance of the slag : If it is perfectly transparent 
 and of a green tint, silica is in excess ; if a light 
 grey or bluish enamel, or translucent glass, the 
 earthy bases, lime and alumina, are in proper propor- 
 tion ; but if stony and rough, or crystalline in fracture 
 and dull in lustre, it is too basic. 
 
 If the product, instead of being melted, is only 
 fritted, and contains the reduced iron interspersed as a 
 fine grey powder, both silica and alumina are deficient 
 in the flux, lime and magnesia being in excess. The 
 latter is one of the most refractory substances found in 
 iron ores, and, where present in quantity, requires an 
 addition of both silica and lime. 
 
 A vesicular slag, with the iron interspersed in mal- 
 leable scales, indicates the presence in the ore of 
 silicates of iron and manganese, or an excess of silica, 
 which react on the carburetted iron as it forms, pro- 
 ducing malleable iron and carbonic acid ; the latter gas 
 escaping through the slag, gives it a spongy character. 
 This defect is to be corrected by the addition of lime. 
 
 Manganese, when in small quantity, gives the well- 
 
110 
 
 METALLURGY OF IRON. 
 
 known amethystine tint to the slags ; in larger proper* 
 tion it renders them yellow, green, or brown. The 
 duller colour is said to be due to the formation of 
 sulphide of manganese. 
 
 The fracture of the button obtained in the assay pre- 
 sents indications of the presence of foreign bodies much 
 in the same way as that of pig iron produced on the 
 large scale. Thus a hard brittle white metal contains 
 phosphorus ; sulphur produces a strong, reticulated, 
 mottled structure ; manganese a bright crystalline cha- 
 racter, resembling spiegeleisen ; titanium a duller grey, 
 reticulated texture ; while a dark grey graphitic metal 
 shows that the ores are easily reducible, or that a very 
 high temperature has been obtained in the furnace. 
 No exact information as to the quantitative composition 
 of the iron likely to be produced from the ore on the 
 large scale can, however, be directly obtained from the 
 assay, as the conditions under which it is performed 
 the ore and fluxes being in a state of intimate con- 
 tact, and the quantity of fuel unlimited represent a 
 favourable combination of circumstances totally unat- 
 tainable in the smelting furnace. 
 
 Wet Assay. When bichromate of potash, dissolved 
 in water, is added to the acid solution of a protosalt of 
 iron, the latter is converted, at the expense of the oxygen 
 of the chromic acid, into a persalt, with the simultaneous 
 production of a potash salt, a sesquisalt of chromium, and 
 water. The following expresses the reaction with pro- 
 tochloride of iron dissolved in hydrochloric acid : 
 
 6 Fed* + 14 HC1 -f K 2 2 CrO' 
 3 Fe 2 d 6 -f 2 KC1 + 7 H 2 + Or 2 Cl 6 . 
 
 When a solution of permanganate of potash is substi- 
 tuted for the bichromate, the formula becomes : 
 10 FeCP + 16 HC1 -f- K 2 Mn 2 7 = 
 10 Fe 2 Cl 6 -|- 2 KC1 + 8 H 2 + 2 MnCl*. 
 
ASSAY AND ANALYSIS OF IRON ORES 111 
 
 The termination of the reaction can in cither case be 
 easily determined, The permanganate solution is of a 
 deep rose-red colour, which is entirely discharged as 
 long as any protochloride remains unaltered ; but the 
 smallest drop in excess, owing to its strong colouring 
 power, communicates a decided pink tint to the assay. 
 
 With bichromate of potash an indirect method must 
 be employed, as the change of colour is not sufficiently 
 marked to indicate the moment of complete peroxida- 
 tion of the iron. For this purpose, a very weak and 
 nearly colourless solution of ferricyanide of potassium, 
 or red prussiate of potash, is used, which produces a 
 bluish-green tint when mixed with protosalts, but is 
 unaltered by per salts of iron. 
 
 If in the above experiments the oxidising solutions 
 be made of a known strength, and be supplied from 
 graduated glass vessels, the cubic volume consumed in 
 either case will furnish us with a ready method of 
 computing the amount of iron contained in the solution 
 operated upon. 
 
 According to the laws of chemical proportions, 151 
 grains of bichromate of potash correspond to 168 grains 
 of iron in the first of the above formulae, and 158 grains 
 of permanganate of potash to 280 grains of iron in the 
 second, or 0*898 grains of the former and 0*564 grains 
 of the latter salt are respectively equivalent to 1 graic 
 of pure iron. 
 
 Both of the above methods are used in practice ; tf\ey 
 are known after the names of the chemists who intro- 
 duced them the permanganate process as Marguerite's, 
 and the bichromate as Penny's process. The latter, 
 although somewhat the more complicated, owing to the 
 use of the second test solution, is perhaps the more 
 generally useful of the two, its indications not being 
 
112 METALLURGY OF IRON. 
 
 interfered with by the presence of organic matter, as is 
 the case with the other. The principal operations in 
 the wet assay of iron are as follows : 
 
 1. Preparation of the standard solutions. 
 
 2. Solution of the ore. 
 
 3. Reduction of the iron to the state of a protosalt. 
 
 4. Oxidation of protosalt of iron by standard solution 
 Preparation of the Standard Solution. For ordinary 
 
 assaying purposes it is most convenient to adjust the 
 solutions in such a manner that 1,000 grains, or other 
 unit measures, will exactly correspond to 10 grains or 
 other unit weights of metallic iron, so that the per- 
 centage of the ore may be found directly from the 
 number of measures consumed without the trouble of 
 calculation. The necessary proportions are 315 grains 
 of bichromate or 197 grains permanganate to half a 
 gallon of distilled water. The latter solution must be 
 carefully kept from contact with organic matter in a 
 glass-stoppered bottle. That of the bichromate is more 
 stable, and can be preserved for a long period without 
 alteration if protected from evaporation. 
 
 "When greater accuracy is required, as, for example, 
 in analytical determinations, solutions of half the above 
 strength, 1,000 measures, corresponding to 5 grains of 
 iron, are to be preferred. 
 
 The red prussiate solution required in Penny's pro- 
 cess, must be very weak, from 2 to 3 grains being suf- 
 ficient for half a pint. It is used in small spots, which 
 are dropped on a white porcelain slab from the end of a 
 glass rod. A drop of the solution under assay is con- 
 veyed to the slab in a similar manner, and mixed with 
 one of the spots, when a blue tinge will be produced as 
 long as any unaltered protosalt of iron remains. The 
 addition of the standard solution must therefore be 
 
ASSAY AND ANALYSIS OF IRON ORES. 113 
 
 continued, testing by drops at short interva_, until the 
 yellowish colour of the prussiate spots can no longer be 
 changed. 
 
 When large quantities of standard solutions are kept, 
 it is necessary, from time to time, to readjust them, or, 
 what is preferable, to determine their absolute value. 
 This is done by dissolving a weighed quantity say 
 10 grains of bright iron pianoforte wire, which may 
 be considered as containing 99i per cent, of iron, in 
 hydrochloric acid, and observing the number of mea- 
 sures requisite to convert the protochloride of iron 
 into perchloride in the manner already described. The 
 value so found is to be applied in computing the assays 
 instead of the assumed standard. Crystallised proto- 
 sulphate of iron, FeO. SO 3 -f- 7 HO, or protosulphate 
 of iron and ammonia, FeO. SO 3 + NH 4 0. SO 3 , salts 
 soluble in water, may be used for the same purpose. 
 The latter salt has the advantage of containing exactly 
 one- seventh of its weight of iron. 
 
 Solution of the Ore. This may be conveniently ef- 
 fected in the conical flat-bottomed glass flasks used by 
 gold assayers. A weighed quantity, from 10 to 20 grains, 
 of the ore in a state of fine powder is digested with 
 strong hydrochloric acid at a moderate heat for about 
 half an hour. Some varieties of hematite and magnetite 
 are very difficultly soluble in hydrochloric acid, but 
 can be rendered so, by a preliminary reduction to the 
 metallic state, by heating to redness in an atmosphere 
 of hydrogen or coal-gas. 
 
 When the iron is completely dissolved, any portion 
 of it existing as perchloride must be reduced to the 
 state of protochloride by the addition of metallic zinc, 
 and boiling till the liquid no longer shows a yellow 
 tint. 
 
114 METALLURGY OF IRON. 
 
 Sulphite of soda may be used for the same purposo 3 
 but care must be taken to remove any free sulphurous 
 acid by boiling until the gas is no longer perceptible 
 oy its peculiar smell. In either case, the solution must 
 be diluted with water before the application of the 
 reducing agent. 
 
 Determination of the Iron. The contents of the flask, 
 when cooled, are to be transferred to a porcelain 
 dish, and the standard solution is then added from 
 a graduated tube or burette, the liquor being well 
 stirred after each addition, the termination of the 
 reaction being indicated by the coloration tests already 
 described. 
 
 Blackband ores dissolve in acid with separation of 
 finely-divided carbonaceous matter, which must be 
 removed by nitration if the assay is to be made by the 
 permanganate process, care being taken to prevent per- 
 oxidation of the iron by exposure to the air, by covering 
 the funnel with a glass plate, keeping a piece of zinc 
 on the filter, and washing rapidly with hot water. 
 When the same ores are assayed by Penny's process, 
 the filtration, though not obligatory, is to some extent 
 advantageous, as the dark-coloured suspended particles 
 interfere with the exact determination of the end of 
 the decoloration. 
 
 Zinc cannot be used in the reduction of the solutions 
 obtained from ores containing titanic acid, as it con- 
 verts the perchloride of titanium, Ti Cl 2 , into the sesqui- 
 chloride, Ti 2 Cl 3 . In such cases sulphite of soda is to be 
 employed. 
 
 The amount of iron existing as protoxide in a mixed 
 ore, such as magnetite, may also be determined by the 
 volumetric method. The process is exactly similar to an 
 ordinary assay, except that the reduction with zinc or 
 
ASSAY AND ANALYSIS OF IRON ORES. 115 
 
 sulphite of soda is omitted, the amount of protochloride 
 formed being in equivalent proportion to that of prot- 
 oxide contained in the ore. Care must be taken to 
 exclude air during the operation. If a second deter- 
 mination of the total quantity of iron be then made, 
 the amount of peroxide may be calculated from the 
 difference of the two. This plan only gives correct 
 results when no oxidising agents, such as peroxide 
 of manganese, are present. As in the latter case, 
 chlorine is evolved during the solution in hydrochloric 
 acid, or the protochloride of iron is converted into per- 
 chloride. 
 
 Comparative Yield of Dry and Wet Assays. As the 
 return of the dry assay is made in cast iron, a substance 
 which, as has already been stated, is of very variable 
 composition, containing at times as much as 16 per cent, 
 of other elements, while the wet assay expresses the 
 amount of pure iron in the ore, the results obtained by 
 the former method should in all cases indicate a higher 
 percentage than the wet assay of the same ore. Such 
 an excess is actually observed in practice when the 
 fluxing has been properly conducted, and the assays 
 have been exposed to a sufficiently high temperature. 
 The difference is greatest with those spathic ores that 
 contain a large quantity of carbonate of protoxide of 
 manganese, as a considerable portion of the latter metal 
 is likely to be reduced and alloyed with the iron, giving 
 rise to the variety of metal known as spiegeleisen. With 
 ordinary ores, however, the difference is not so great, 
 the excess being exactly from 2 to 4 per cent. The 
 composition of the assay buttons cannot, however, be 
 directly paralleled with that of the pig iron likely to 
 De obtained from the same ores on the large scale, as 
 the conditions are dissimilar in many important par- 
 
116 METALLURGY OF IRON. 
 
 ticulars. Thus the assay is conducted with a practically 
 unlimited quantity of reducing material, and the ore 
 and flux are in the finest possible state of division, and 
 intimately mixed, so that the reduction may take place 
 under the most favourable circumstances, and such as 
 are not always obtainable in the blast furnace. Except, 
 therefore, when conducted as fluxing experiments, the 
 results of the dry assay are less valuable than those 
 obtained by the wet assay, which is in all cases to be 
 preferred when it is desired to ascertain the exact 
 percentage of iron contained in the ore. 
 
 The following series of dry assays of magnetic ores, 
 compared with corresponding analytical determinations 
 of the iron, show a different result, the assays in almost 
 all cases giving a lower produce. The method adopted 
 was a somewhat dissimilar one from that usually em- 
 ployed, as the ores were reduced either without flux, or 
 with at most 5 per cent, of lime. 
 
 I. II. III. IV. V. VI. VII. 
 
 Iron by dry assay 59'0 58-0 66-0 66-0 58-0 59-0 71-0 
 analysis . 60-9 59'6 66'6 67'8 59'6 61-2 65-6 
 
 The chief cause of these differences is to be sought 
 in the more perfect fusibility of the earthy matters in 
 some of the samples. The whole number were crys- 
 talline magnetites, associated with hornblende, chlorite, 
 carbonate of lime, and quartz from the Roslagen dis- 
 trict, in Sweden. 
 
 Analysis of Iron Ores. The following sketch of the 
 processes followed in the systematic analysis of iron 
 ores is derived from the " Memoir on the Iron Ores of 
 Great Britain," founded on an elaborate investigation 
 of English and Welsh iron ores, conducted by Messrs. 
 Dick and Spiller in the laboratory of the HoyaJ. SchooJ 
 
ASSAY AN> ANALYSIS OF IRON ORES. 117 
 
 of Mines, under the direction of Dr. Percy, published 
 in part between the years 1856 62. 
 
 The chief components determined in the analysis of 
 iron ores for metallurgical purposes are estimated in 
 the following order : 
 
 1. Insoluble Matter. A weighed quantity of the ore 
 finely powdered is digested in strong hydrochloric 
 acid until no further action takes place, and then 
 boiled for fifteen minutes before dilution. The in- 
 soluble portion is then separated by filtration, and 
 after having been well washed with boiling water, 
 is dried, separated from the filter, ignited to redness, 
 and weighed. Its subsequent treatment will be de- 
 scribed further on. 
 
 2. Hydrochloric Acid Solution. After peroxidisation 
 of iron by nitric acid, or chlorate of potash when neces- 
 sary, the filtrate from No. 1, rendered nearly neutral 
 with ammonia, is boiled with an excess of acetate of 
 ammonia, and filtered hot. The precipitate is washed 
 with hot water. The filtrate is received in a flask 
 rendered alkaline with ammonia, and after the addition 
 of a few drops of bromine is carefully corked, and 
 allowed to stand for twenty-four hours. It is then 
 heated and rapidly filtered. The precipitate of hydrated 
 peroxide of manganese is, on ignition, converted to 
 mangano -manganic oxide, Mn 3 4 . The filtrate from 
 the last operation contains lime and magnesia ; the 
 former is precipitated by oxalate of ammonia, and is 
 either weighed as carbonate, or sulphate : it is converted 
 into the former by ignition, or into the latter by moisten- 
 ing with sulphuric acid, and heating until the excess 
 of acid is driven off. The filtrate from the precipi- 
 tated oxalate of lime is heated with phosphate of 
 soda and excess of ammonia, and allowed to stand 
 
118 METALLURGY OF IRON. 
 
 for twenty -four hours, during which time a granulai 
 precipitate of phosphate of magnesia and ammonia 
 separates. This is collected on a filter, and as it is 
 sensibly soluble in pure water, must be washed with 
 water containing a little ammonia. By ignition, the 
 precipitate which has the composition (2 MgO. NH 4 0.) 
 P 2 5 loses its ammonia, and is converted into bibasic 
 phosphate of magnesia, and may then be weighed, and 
 the amount of magnesia computed. 
 
 The first precipitate produced in the hydrochloric 
 acid solution, consisting of basic acetates of iron and 
 alumina and phosphoric acid, is to be dissolved in hydro- 
 chloric acid, and boiled with excess of caustic potash 
 in a platinum, or what is preferable, a gold basin. 
 Both peroxide of iron and alumina are at first precipi- 
 tated by this treatment, but the latter oxide subse- 
 quently redissolves, and is separated by filtration. The 
 filtrate is acidified with hydrochloric acid, and boiled 
 with an addition of chlorate of potash for the purpose 
 of destroying any soluble organic matter due to the 
 action of the caustic alkali on the filter paper, nearly 
 neutralised with ammonia, and finally rendered alkaline 
 with carbonate of ammonia, when the alumina, with 
 some phosphoric acid in combination, goes down in an 
 insoluble form, and is collected and weighed after 
 washing and ignition. The amount of phosphoric acid 
 is determined by a special process, and deducted from 
 the former weight : the difference gives the corrected 
 amount of alumina. 
 
 The precipitate of hydrate of peroxide of iron re- 
 maining after separation of the alumina usually con- 
 tains a -iniall quantity of silica, and is therefore not 
 subjected to any further treatment, as the amount of 
 iron may be more accurately determined by standard 
 
ASSAY AND ANALYSIS OF IRON ORES. 119 
 
 solution of bichromate of potash in the manner already 
 described for the wet assay. 
 
 Determination of Phosphorus. A weighed quantity 
 of the ore is digested with hydrochloric acid, and filtered 
 from the insoluble residue. The filtrate, which should not 
 be too acid, is treated with sulphite of soda to reduce the 
 iron to the state of protochloride, nearly neutralised 
 with carbonate of soda, acetate of soda is added in excess, 
 and the liquid boiled. A strong solution of perchloride 
 of iron is then added until the precipitate formed has a 
 decidedly red colour. This precipitate, which contains 
 all the phosphoric acid present in the ore, is, after 
 filtration and washing, dissolved in hydrochloric acid, 
 tartaric acid and ammonia being added to the solution 
 to prevent the precipitation of the iron. The phos- 
 phoric acid is then separated as phosphate of magnesia 
 and ammonia by the addition of chloride of ammonium, 
 sulphate of magnesia, and ammonia, care being taken 
 to conduct the operation in the manner already de- 
 scribed for the determination of magnesia. 
 
 Determination of Sulphur. This may exist under two 
 different conditions in the ore, either as soluble sul- 
 phates, or sulphides decomposable by hydrochloric 
 acid, or as bisulphide of iron, which is not affected by 
 that reagent. For the determination of the sulphuric 
 acid, the solution obtained by digestion of a weighed 
 quantity of the ore in hydrochloric acid is treated with 
 chloride of barium, with the production of an insoluble 
 precipitate of sulphate of baryta, which is collected on 
 a filter, and estimated apart. Iron pyrites, if present, 
 will be found in the insoluble residue, which is to be 
 fused with nitre and carbonate of soda in a gold 
 crucible. The fused mass is then dissolved in hydro- 
 chloric acid, evaporated to dryness, redissolved, and 
 
120 METALLURGY OF IRON. 
 
 filtered from the insoluble residue. The sulphuric ar id 
 formed by the oxidising action of the nitre on the 
 pyrites will be found in the last filtrate, and is pre- 
 cipitated by the addition of chloride of barium as 
 before : 100 parts of sulphate of baryta correspond 
 to 34'37 of sulphuric acid, 25'48 of iron pyrites, or 
 13-75 of sulphur. 
 
 Analysis of Insoluble Residue. The examination of the 
 residue insoluble in hydrochloric acid, is not usually 
 carried out in commercial analysis, being generally 
 returned as " insoluble siliceous matter ; " it is, how- 
 ever, more satisfactory to determine its composition, 
 as without a complete analysis, an element of value in 
 the working of the ore, namely, the presence of easily 
 fusible earthy silicates, such as garnet, hornblende, 
 &c., may be overlooked. The residue from the first 
 operation must be fused with four times its weight of 
 carbonates of soda and potash mixed in equal pro- 
 portions ; the fused mass is then dissolved in dilute 
 hydrochloric acid, evaporated to dryness, the residue 
 moistened with strong hydrochloric acid, and after 
 standing for some hours, digested with hot water and 
 filtered. Silica and titanic acid are rendered insoluble 
 by this treatment, while the filtrate contains all the 
 alumina, iron, lime, and magnesia that may be present, 
 which are to be separated by the methods already 
 described. 
 
 If the precipitated silica contains titanic acid, it may 
 be separated from it, by mixing with sulphuric acid, and 
 exposure in a platinum dish for several hours to the 
 action of hydrofluoric acid in a closed lead chamber, 
 when the silica volatilises, leaving a residue, consisting 
 mainly of titanic acid, in addition to small quantities 
 of alumina and peroxide of iron. 
 
ASSAY AND ANALYSIS OF IRON ORES. 121 
 
 The examination for titanic acid is a difficult and 
 troublesome process, as a certain quantity is usually dis- 
 solved by hydrochloric acid, goes down with the iron in 
 the analysis of the soluble portion, and can only be 
 rendered insoluble by ignition. In like manner, in the 
 treatment of the insoluble residue, a portion goes into 
 solution unless the fused mass be strongly heated before 
 re-dissolving. 
 
 Determination of Water. The accidental or hygro- 
 scopic moisture is found by exposing a weighed 
 quantity of the ore in powder to a heat not exceed- 
 ing that of boiling water, and re- weighing to deter- 
 mine the loss. For combined water the dried residue 
 is placed in a hard glass tube, to which is adapted a 
 weighed tube containing fragments of fused chloride of 
 calcium. The powder is then gradually raised to a low 
 red heat, whereby water and other volatile matters in 
 combination are expelled ; but of these, only the former 
 is absorbed by the chloride of calcium, so that its 
 amount may be found directly by re-weighing the tube. 
 
 Determination of Carbonic Acid. This may be effected 
 by decomposing a weighed quantity of the ore with 
 sulphuric acid in a small flask provided with a delivery 
 tube, carrying the gas into a second flask containing 
 strong sulphuric acid, which absorbs any water carried 
 over. Carbonic acid only escapes, and is determined 
 by the loss of weight of the apparatus. 
 
 The preceding are the principal substances usually 
 determined in analyses for metallurgical purposes. 
 The complete operation is both difficult and tedious, 
 involving numerously repeated precipitations, nitra- 
 tions, and washings, and, in some cases, requiring 
 between thirty and forty determinations of weight in 
 the examination of a single ore. The advantages to be 
 
 G 
 
122 METALLURGY OF IRON. 
 
 gained from such analyses are, however, very great, 
 especially in the case of new or unknown minerals, 
 which are not generally adopted in the smelting pro* 
 cess without preliminary chemical investigation. 
 
 The analyses of cast and wrought iron and steel are 
 conducted in a particular manner, and will be noticed 
 after the description of the processes by which these 
 Tietals are obtained. 
 
 CHAPTER V. 
 
 PREPARATION OF IRON ORES. 
 
 IN England it is not usual to subject iron ores to any 
 complex mechanical treatment or dressing, such as is 
 usual with the ores of other metals, as the low price 
 of workable ores, together with the facility for obtain- 
 ing supplies, renders it almost impossible to improve 
 poor or inferior ores advantageously. But on the Con- 
 tinent, in many parts of France, Belgium, and Germany, 
 argillaceous brown iron ores of low produce are sepa- 
 rated from a portion of the intermixed clay and sand 
 by sifting, crushing, or stamping, and washing. This 
 is more especially the case with the lenticular or piso- 
 litic ores of the oolitic and cretaceous formations 
 (bohnerz). As the chief object is, however, to remove 
 such finely-divided matters as can be carried away by 
 a stream of water from the larger masses of ore, the 
 breaking machinery must be so combined as to produce 
 the smallest amount of dust. Roller-crushing mills 
 are therefore to be preferred to stamps. Irregular 
 hollow nodules of brown iron ore, such as found in the 
 Greensand formation, and other sandy limoiiites, may be 
 
PREPARATION OF IRON ORES. 123 
 
 separated from the adherent sand by dry-sifting ; and 
 by cracking the nodules, a further portion of loose sand 
 will often fall out of the interior. 
 
 The machinery used for washing iron ores is gene- 
 rally of a very simple character. The commonest 
 arrangement consists of a horizontal shaft, armed with 
 projecting knives or paddles, revolving in a cylindri- 
 cal trough, through which a stream of water is kept 
 flowing. The rough ore, after being well mixed up 
 with the water by the action of the paddles, is carried 
 by the stream into a settling launder or pit, where the 
 heavier masses of clean ore deposit, while the finely- 
 divided earthy matter is carried off with the waste 
 water. "When fine-grained soft ochreous ores are sub- 
 jected to washing, a large quantity of finely-divided 
 hydrated peroxide of iron is liable to be carried off by 
 the stream, together with the clay. In such cases it 
 is necessary, if it is desired, to avoid a considerable loss 
 of iron, to collect the slimes in catch-pits, and subject 
 them to further treatment. An instance of this kind 
 is furnished in the preparation of the ores produced at 
 the Cornelia mine, near Stolberg, in Hhenish Prussia, 
 where argillaceous yellow ochreous ore, after a pre- 
 liminary spalling or breaking by hand, is subjected 
 to the action of a vertical rotating agitator in a 
 circular trough, through which a constant current 
 of water is kept flowing. The fine muddy particles 
 are removed by the stream, while the ore remaining 
 behind is thrown on to an iron riddle, and the small 
 pieces falling through are washed in a slightly in- 
 clined plane in a stream of water. The slime, together 
 with that from the former operation, is carried into 
 settling pits, and deposits a ferruginous mud, which, 
 when sufficiently dry, is moulded into bricks and burnt, 
 
 G2 
 
124 METALLURGY OF IRON. 
 
 yielding a product containing from 40 to 43 per 
 cent, of iron. The production is about 25 tons per 
 day of twelve hours, at a cost of 17s., or 7ff/. per 
 ton, for washing. It is obvious that the above 
 process is not susceptible of being applied to any 
 great extent, a certain binding quality being neces- 
 sary in order to give bricks of sufficient cohesive 
 strength to withstand the crushing effect of a high 
 blast furnace. This difficulty has hitherto prevented 
 the smelting of certain finely-divided ores of high 
 percentage, such as the magnetic and titaniferous iron 
 sands of New Zealand and the St. Lawrence coasts of 
 Labrador, as, if used alone, they either stop the draught 
 of the furnace altogether, or are blown out at the 
 throat, if the blast be increased to overcome the ob- 
 struction. Yarious plans have been proposed for mix- 
 ing these sands with clay or other binding materials, 
 but hitherto without success, on account of the great 
 expense when compared with the value of the product 
 obtained, whose price will of course be measured by 
 the local cost of ores fit for smelting without prepara- 
 tion. 
 
 In Belgium the washing of iron ores is conducted in 
 inclined cylindrical drums of cast iron, 32 inches 
 diameter, and 6J feet long, armed internally with 
 projecting spikes, which are made to rotate, while 
 the ore is fed in at the upper end, a stream of water 
 passing through at the same time. The particles of 
 ore and clay loosened by the tearing action of the 
 spikes, are discharged at the lower end into a trough, 
 where they are separated by a current as in the pre- 
 ceding instances. In Wurtemberg and Baden pisolitic 
 brown iron ores contained in a ferruginous and calca- 
 reous marly matrix are cleaned by the method of 
 
PREPARATION OF IRON ORES. 125 
 
 jigging, hand sieves, of one- twelfth of an inch aperture, 
 being employed, which are subjected to a gyrating 
 motion in a tub of water. The cleaned grains of larger 
 size remain on the sieve, while the fine stuff sinks in 
 the tub, depositing a second quality of ore or hutch- 
 work in the tub : the waste slime is allowed to run 
 off by a hole near the bottom. By the adoption of some 
 of the newer forms of jigging machinery this process 
 may be made continuous in its action, but only by an 
 increased consumption of washing water, and corre- 
 sponding loss of material, to which must be added the 
 interest on capital and cost of maintenance of machinery. 
 In most cases, therefore, it will be found preferable to 
 work in the furnace with ores of lower produce, when 
 they are not inadmissible from excess of actually de- 
 leterious ingredients, such as iron pyrites, phosphate 
 of lime, &c., rather than to concentrate them by 
 mechanical means to a higher produce. An example of 
 this is furnished by the magnetiferous dolerite of Taberg 
 in Sweden, containing from 25 to 30 per cent, of iron. 
 This, when concentrated by dressing to 43 per cent., 
 gave a product which, on account of its finely divided 
 state, worked so badly in the furnace, that it was found 
 to be better to smelt it in its natural condition, the 
 expense due to the increased consumption of fuel being 
 compensated by greater facility in treatment. 
 
 Weathering. The argillaceous ores of the coal 
 measures occurring in nodules, are often difficult to 
 separate from adherent fragments of shale when first 
 raised ; if, however, they be exposed to the action of 
 the air for some time, superficial oxidation takes place, 
 the shale disintegrates, and can readily be removed. 
 In like manner, ores containing sulphides, such as 
 copper, iron, and magnetic pyrites, when exposed to 
 
126 METALLURGY OF IRON. 
 
 atmospheric air and moisture, give rise to soluble 
 sulphates which may be partially removed by rain. 
 The beneficial effect of this process, which applies more 
 particularly to spathic ores, may be increased by water- 
 ing the heaps during dry weather, for the purpose of 
 washing out the soluble salts formed, also turning them 
 over to expose fresh surfaces from time to time. In 
 the Harz, hard silicated ores are subjected to this treat- 
 ment for a period of several years before smelting, but 
 such a course could only be followed in works where 
 the yield is comparatively small. Spathic ores, at the 
 same time, undergo a superficial alteration by exposure, 
 being converted into brown hematite. The same change 
 takes place in a slight degree with nodules of clay iron 
 ores, especially such as contain no carbonaceous matter. 
 In all cases where ores are allowed to weather, care 
 must be taken not to push the process too far, as in 
 some instances absolute disintegration into small frag- 
 ments or powder ensues, if the exposure be continued 
 for too great a length of time. This remark applies 
 specially to ores containing carbonate of lime, which, 
 if exposed to the air for any length of time after cal- 
 cination, fall to pieces, on account of the slacking of 
 the caustic lime, produced by the decomposition of the 
 carbonate in the roasting kiln. Such ores should, there- 
 fore, be carefully covered if not required for immediate 
 use in the blast furnace. 
 
 At Ilsenberg, in the Harz, pyritic and siliceous 
 hematite and magnetite, after crushing and washing, 
 are exposed to the air for a period of from two to three 
 years, in heaps from 2 to 3-J- feet high, during which 
 time they are repeatedly washed with water. After- 
 wards they are again passed through the crusher, and 
 exhausted with water during a whole summer season, 
 
PREPARATION OF IRON ORES. 
 
 127 
 
 if pyrites exist in quantity. At Altenau, ores of a 
 similar character are prepared by laying out in the air 
 for one year, without the addition of water, after com- 
 ing from the roasting kiln. 
 
 At Golrad, in Styria, spathic ores are exposed to the 
 weather for a period of five years before being deli- 
 vered to the smelter, during which time the amount of 
 sulphur is reduced from 3*68 to 0'20 per cent. 
 
 The presence of carbonate of lime in these ores is a 
 great obstacle to the removal of the sulphur by the 
 action of water after roasting, as the caustic lime 
 formed, decomposes the sulphates of iron and copper 
 with the production of gypsum and hydrated oxides, or 
 basic sulphates, which latter are insoluble in water, and 
 cannot, therefore, be removed by mere washing. The 
 same is true of the gypsum, which although soluble, 
 is not to the same extent as the sulphate so, whose 
 expense it is formed. 
 
 According to Liiders, from 2 to 3 per cent, of lime 
 and magnesia in a spathic ore is sufficient, when the 
 sulphur does not exceed from 0'3 to 0'5 per cent., to 
 combine with the sulphuric acid, and to decompose the 
 sulphate of copper formed by roasting four parts of 
 sulphur combining with seven of lime to form gypsum. 
 With larger amounts of pyrites, when the quantity of 
 sulphur is increased to 1'2 per cent., the lime and 
 magnesia are only sufficient to take up the sulphur 
 set free by roasting, while the sulphate of copper 
 formed remains undecomposed, and can be removed by 
 washing with water. These reactions are sufficient to 
 account for the common presence of copper in pig iron 
 smelted from spathic ores. 
 
 The removal of phosphoric acid from iron ores by 
 
128 METALLURGY OF IRON. 
 
 means of hydrochloric acid after roasting has Deen 
 tried, but cannot be done to profit. Sulphurous acid is 
 used for the same purpose at Kladno, in Bohemia it is 
 said with successful results. 
 
 Ironstone Breakers. In order to attain the greatest 
 regularity in working blast furnaces, it is advisable that 
 all charges of ores and fluxes should be reduced to 
 fragments of nearly uniform dimensions. The size of 
 the fragments should be proportioned to the height 
 of the furnace, and the greater or less susceptibility or 
 reduction of the ore. Thus in large furnaces, such as 
 those of the hematite districts in Lancashire, it is found 
 convenient to break both ore and fluxes to the size of 
 ordinary road metal, or cubes from 1 J to 2 inches in 
 the side. In Sweden, hard magnetic ores, after roasting, 
 are crushed to about f to 1 inch cubes. The Cleveland 
 furnaces, as a rule, take the ore in much larger blocks, 
 often as much as 4 or 6 inches in the side. The limits 
 in either direction are to be determined by a comparison 
 of conditions, which are different in each district, the 
 larger masses being only adapted for tall furnaces, 
 where, by the slow descent of the charges, sufficient 
 time is allowed for the heat to penetrate to the interior, 
 at the same time that a free passage is afforded to the 
 upward current of gases. Smaller pieces, on the other 
 hand, although exposing a greater surface to the action 
 of the reducing gases, pack closer together, and offer 
 greater resistance to the blast. 
 
 The reduction in size may be effected either by 
 manual or mechanical means ; but there are probably 
 very few iron-making districts in the world where the 
 former method can be applied at the present day, unless 
 it is requisite to combine the breaking with hand-pick- 
 ing in the removal of injurious substances, such as 
 
PREPARATION OF IRON ORES. 129 
 
 heavy-spar, &c. Of the various mechanical methods 
 of breaking, the most advantageous are roller crushers, 
 and the new lever machine, known as Blake's rock 
 breaker. Tilt or other forms of lever hammers may 
 also be used, while stamps are in most cases objection- 
 able, except with very hard ores, from their pulverising 
 action, producing a proportionably larger quantity of 
 dust. This may, to a certain extent, be avoided by 
 substituting a grated floor for the stamp-heads to work 
 upon, instead of the ordinary solid bed, so that the 
 fragments, as soon as they are broken sufficiently small, 
 fall through the spaces between the bars, without being 
 subjected to an unnecessary amount of pounding. 
 
 At Finspong, in Sweden, a tilt-hammer, striking 60 
 blows per minute, breaks from 15 to 16 cwts. per hour 
 to f inch. size. The ores are magnetite and specular 
 schist, which have been previously roasted. 
 
 Crushing Rotters are used to a considerable extent 
 for breaking iron ores, having the advantage of pro- 
 ducing fragments of a tolerably uniform size without 
 much dust. It is essential, however, that the material 
 operated upon should not be too hard ; they are there- 
 fore better adapted for roasted than raw ores. As an 
 example of a large ironstone crusher of this form may 
 be mentioned that at Eisenerz, in Styria, employed 
 for breaking spathic ores after roasting. It has a single 
 pair of rolls, 18 inches in diameter and 12 inches wide, 
 whose bearings are carried on spring beams, which 
 allow a certain play to the rolls, in case of the resistance 
 being increased by the introduction of lumps of raw 
 stone by mistake. The rolls, being set to a distance 
 of about 1J inches, receive the roasted ore in lumps of 
 from 20 to 30 cubic inches, and deliver it at a 
 maximum size of 4 to 5 cubic inches, from 1J to If 
 
130 METALLURGY OF IRON. 
 
 inch cube. When making 36 revolutions per minute; 
 the amount passed through per hour is about 40 tons ; 
 but increasing the opening to If inches and the number 
 of revolutions to 40 or 42, from 60 to 75 tons may be 
 broken in the same time, the amount of power expended 
 in either case being 19 and 24 horse power respectively. 
 
 Blake's rock breaker resembles an ordinary pair of 
 nut-crackers, supposing one jaw to be fixed to a vertical 
 framing, while the opposite one receives a reciprocating 
 motion about its hinge. This is effected by means of 
 a powerful combination of levers actuated from a 
 rotating shaft. The faces of the jaws are corrugated 
 into shallow Y-shaped grooves, placed in parallel 
 vertical lines. At every revolution of the crank, the 
 movable jaw advances about of an inch toward 
 the fixed jaw, and returns. During the latter part of 
 the stroke, the stone grasped between the two jaws 
 falls into the space provided by the withdrawal of the 
 movable one, and receives and is subjected to an in- 
 tense grinding pressure at the next bite, and so on 
 until it is broken sufficiently small to pass out at the 
 bottom. At the Kirkless Hall iron works, near Wigan, 
 one of these machines, of 20 inches breadth of face, 
 and capable of taking in stones not exceeding 7 
 inches in thickness, making from 200 to 250 revolu- 
 tions per minute, breaks up red hematite ore and lime- 
 stone for the furnaces at the rate of between 10 and 
 12 tons per hour. The size of the fragments delivered 
 is about IJ-inch cube. A larger machine of the same 
 construction, with a top aperture of 20 inches broad 
 and 10 inches wide, used entirely for crushing limestone, 
 requires 15 -horse power to drive it. 
 
 At Wyandotte iron works, near Detroit, and all the 
 charcoal furnaces on Lake Superior, the same machine 
 
ROASTING OR CALCINATION OF IRON ORES. 131 
 
 is used for breaking the hard red slaty hematite noticed 
 at p. 66 as occurring in the Huronian rocks, near 
 Marquette. This is a very intractable material, as it 
 combines both hardness and toughness in a high 
 degree. The lower corners of the movable jaw are 
 often broken off during the crushing. The crushing 
 faces are movable, so that they can be replaced whei> 
 worn out or broken. The greatest durability is ob- 
 tained by the use of a metal composed of strong mottled 
 iron, with a proportion of Franklinite spiegeleisen, the 
 wearing surfaces being strongly chilled. 
 
 
 CHAPTER VI. 
 
 ROASTING OR CALCINATION OF IRON ORES. 
 
 WITH the exception of massive red hematite and cer- 
 tain varieties of magnetite, it is usual to subject all 
 kinds of iron ores to the process of roasting before 
 smelting. The advantages gained by this operation 
 are of two kinds : the amount of iron is concentrated 
 into a smaller weight by the removal of water, carbonic 
 acid, and other volatile matters ; and, as the fragments 
 of mineral retain their form, they are rendered porous 
 and more readily susceptible of being changed in the 
 subsequent operations in the furnace. Another object 
 is the decomposition of sulphides, such as iron pyrites, 
 &c., which are altered by heating in an oxidising 
 atmosphere to oxides, the whole of the sulphur being 
 volatilised if the temperature be sufficiently high. 
 Protoxide compounds, such as the protocarbonato of 
 iron, absorb oxygen, and are partially peroxidised, with 
 the production of magnetic oxide. The same change 
 
1:32 
 
 METALLURGY OF IRON. 
 
 takes place in a less degree with magnetite, the hard 
 black Swedish varieties, after calcination, occasionally 
 presenting an outer red crust of peroxide. This ab- 
 sorption of oxygen, though to a certain extent dis- 
 advantageous when considered in reference to economy 
 of fuel, as peroxide of iron requires a greater quantity 
 of carbon for its reduction to the metallic state than 
 the protoxide, has an important practical advantage, as 
 the higher oxide is almost indifferent in its relations to 
 silicas at high temperatures, while the protoxide enters 
 readily into combination under similar conditions, with 
 the production of a highly basic slag, which can only 
 be reduced to the metallic state with difficulty. 
 *s~ The various methods of roasting iron ores may be 
 * classified under three different heads, namely : 
 
 1. Roasting in clamps or piles in the open air 
 
 2. Roasting in the open air, the heat being confined 
 between walls. 
 
 3. Roasting in furnaces or kilns. 
 
 The first of the above methods is principally used in 
 localities where fuel is cheap when compared with the 
 price of labour, but is in many respects disadvantageous, 
 on account of the waste of fuel and the imperfect dis- 
 tribution of the heat, the interior of the piles often 
 being heated to excess, with a partial fusion of the ore, 
 when the outer parts have only attained the proper 
 temperature. 
 
 In Staffordshire and South Wales clamps are effected 
 in the following manner : A bed of coal, a few inches 
 in thickness, is laid upon a level surface, and covered 
 with a layer of ironstone from 10 to 12 inches in 
 depth ; this is succeeded by fresh layers of coal and 
 stone, till the pile has reached a height of 4 or 5 feet. 
 The heap is then lighted at the bottom, and continues 
 
ROASTING OR CALCINATION OF IRON OKES. 133 
 
 to burn until the whole of the fuel is consumed. If the 
 fire should come to the surface too rapidly, the draught 
 must be checked by damping the spot with small ore 
 or ashes, otherwise a partial fusion may take place, and 
 the lumps of stone become clotted together. About 2 j 
 cwt. of small, and j cwt. of large coal are consumed 
 per ton of ore roasted. The loss of weight is from 
 28 to 33 per cent., an amount that is made up of the 
 water and carbonic acid driven off, diminished by the 
 oxygen taken up in the conversion of the protoxides of 
 iron and manganese into magnetic oxides. 
 
 Blackband ironstones usually contain sufficient car- 
 bonaceous matter to effect the roasting without any 
 additional fuel : a layer of coal slack is, however, 
 generally placed at the base of the pile to start the com- 
 bustion. In Scotland and Staffordshire the piles are 
 usually made of a trapezoidal form, 3 to 9 feet in height. 
 The smaller dimensions are to be preferred for the more 
 highly carbonaceous ores, in order to avoid the produc- 
 tion of too high a temperature. The spathic carbona- 
 ceous ores, known in South Wales as coal-brasses, appear 
 to be peculiarly liable to fusion in calcination, although 
 containing neither sulphur nor silica, from the produc- 
 tion of a fusible ferrite of magnesia, MgO + Fe 2 3 . 
 
 In Westphalia, blackband is roasted in heaps 120 feet 
 long, 30 feet broad, and 4 feet high, enclosed between 
 walls built up of the larger lumps, small square openings 
 being left at intervals of 12 feet along the sides. These 
 draught-holes communicate with passages 3 feet deep in 
 the interior of the heaps, which are filled with wood. 
 Small ore is heaped against the sides of these passages, 
 and the larger blocks are placed towards the middle, in 
 order to guide the flame as much as possible into the 
 heart of the pile. After the wood has burnt down, and 
 
134 
 
 METALLURGY OF IRON. 
 
 the heap is fully ignited, the wall is pulled down, and 
 the debris are thrown upon those places where the fire 
 shows a tendency to come to the surface too quickly, 
 in order to damp it. A heap of the above dimensions, 
 containing from 500 to 700 tons, takes about a month 
 to burn out. 
 
 When pyrites and coaly matter are present in large 
 quantities, the heaps are only made 2 feet high, in order 
 to prevent fusion in the interior ; in such cases the 
 lumps nearest the surface do not become sufficiently 
 heated. In order to finish the roasting, therefore, a 
 second layer, of 2 feet in thickness, is placed above the 
 first as soon as combustion ceases, while the pile is still 
 hot ; and, in some cases, a third after the second has 
 burnt out, the fire being started in the additions by 
 a few pieces of firewood, upon which red-hot masses of 
 ore are shovelled. If the roasting does not proceed 
 uniformly the hottest places are checked by damping 
 with small ore, while those that are cold and black are 
 started afresh by digging a hole in the pile, and filling 
 it up with red-hot stones from below. The loss of 
 weight varies, with the amount of carbonaceous matter 
 in the ore, from 25 to 50 per cent. 
 
 Grundmann recommends that the heaps should be 
 covered with a coating of small ores when they con- 
 tain much pyrites, in order to condense the sulphur 
 volatilised without oxidation, in consequence of the re- 
 ducing atmosphere produced by the combustion of the 
 coaly matter preventing the formation of sulphurous 
 acid. The coating is then carefully removed and 
 thrown away, unless it be of sufficient value to be used 
 as a sulphur ore. The sulphates remaining in the heap 
 are removed by long- continued exposure to the air, and 
 occasionally watering. Another point to be attended 
 
ROASTING OR CALCINATION OF IRON ORES. 135 
 
 to in such, cases is to pile the blocks of ore with their 
 planes of stratification upright, and not on their na- 
 tural bed, as the pyrites contained in these ores is 
 usually found interspersed in patches between these 
 divisional planes, so that, by placing them on end, the 
 escape of sulphur vapours is facilitated. 
 
 The second method of roasting between walls (stadeln) 
 differs but little from that of open heaps or clamps 
 the heap being enclosed by vertical walls, forming 
 three sides of a square or rectangular figure, and usually 
 having an inclined floor. The height of the walls 
 varies, with the nature of the ores, between 6 and 12 
 feet ; two ranges of draught-holes, of 3 to 4 inches 
 square, being pierced through them about 3 feet 
 vertical distance apart, the lower series being close to 
 the level of the ground. When the enclosed area is 
 very large, it is necessary, in order to promote regu- 
 larity of burning, to build up the large masses of ore 
 so as to form a series of air-shafts in the interior of the 
 heap, to which the air has access through a system of 
 flues in the floor. This method of roasting is not in use 
 in this country, but is practised in the Harz to some ex- 
 tent. The enclosing walls form in reality an imper- 
 fectly enclosed kiln, and there is some saving in the 
 amount of fuel consumed, as compared with open piles. 
 At Ilsenburg, in the Harz, clay ironstones are roasted 
 in this manner, with a consumption of charcoal dust or 
 braise to the extent of 6 or 8 per cent, of the weight of 
 the ore. 
 
 Roasting in Furnaces or Kilns. This method is gene- 
 rally to be preferred, when economy of fuel is of im- 
 portance, as the heat of combustion is more perfectly 
 applied, and a more uniform product is obtained, than 
 is the case with the ruder methods previously noticed, 
 
136 METALLURGY OF IRON. 
 
 The construction of the kilns used in different districts 
 varies considerably, as will be seen by a few de- 
 tailed examples following, but the principle of working 
 is, in the main, the same everywhere the ore being 
 piled above a thin bed of fuel at the bottom of the kiln- 
 shaft, which may be conical, cylindrical, barrel, or 
 wedge-shaped in form, and when ignited is covered 
 with layers of ore and fuel alternately until the shaft 
 is full to the top or throat. The ore roasted by the 
 combustion of the fuel at the bottom, where the air has 
 access to the kiln, is withdrawn, and the next layer 
 falls, the deficiency being made good by fresh charges 
 at the top. In some instances, though not commonly, 
 the heat is kept up by fuel burnt on side grates, so that 
 only the flame has access to the interior of the kiln. 
 Another plan, used to a considerable extent in Sweden, 
 consists in the substitution of the waste gas of the 
 blast furnace instead of solid fuel. 
 
 Kilns, when of a moderate size, are most conve- 
 niently made either of a conical, cylindrical, or any 
 similar form presenting circular horizontal sections. 
 For larger sizes, however, as it is found difficult to 
 maintain a uniform temperature over circular areas of 
 great diameter, the ore in the centre is liable to get too 
 hot. It is preferable to build them of flattened elliptical 
 sections, or rectangular with the corners rounded off. 
 
 At Dowlais, in South Wales, the kilns used are of a 
 flattened elliptical plan (rectangular with semicircular 
 ends), contracted from 9 feet in width at the top to 
 2 feet at the bottom. The length is 20 feet, and the 
 height 18 feet. The floor is made of cast-iron plates 
 2 inches thick, and the interior is lined with fire- 
 bricks, with an exterior casing of rough masonry. 
 Two arched passages, slightly splayed outwards, are 
 
ROASTING OR CALCINATION OF IRON ORES, 137 
 
 left in the lower part of the masonry, on one side 
 extending back to the inner fire-brick lining, which 
 is perforated, within the space covered by the arches, 
 by four rectangular openings at the floor level for with- 
 drawing the calcined ore, as well as by a numerous 
 series of smaller holes above, which serve for the admis- 
 sion of air. The top edge of the kiln is covered 
 by a flanged cast-iron ring, which protects the brick- 
 work from abrasion by the lumps of stone in filling. 
 
 The method of working is as follows : two or three 
 small coal fires having been lighted on the floor of the 
 kiln, raw ironstone is placed on the top and around 
 them until the whole is covered by a layer about 9 
 inches thick ; when this has attained a dull red heat, 
 a second layer is added, with about 5 per cent, by 
 weight of small coal, and so on, fresh layers of stone 
 being added as soon as the preceding charge has been 
 heated to redness. When the kiln is completely filled, 
 the lowest portion will be sufficiently cold and fit for 
 drawing. The capacity of a kiln of the dimensions 
 given above is about 70 tons, and will calcine 146 tons 
 weekly, so that the average time of burning the charge 
 is about three days and a half. The consumption of 
 small coal is at the rate of 1 cwt. per ton of ore, 
 whereas in calcining in piles or clamps 2 cwt. of 
 small and i cwt. of large coal are required to do the 
 same amount of work. The average loss of weight of 
 Welsh argillaceous ores, when calcined, is 27 per cent. ; 
 of blackbands, from 40 to 60 per cent. ; of red hema- 
 tite, about 6 per cent. ; and of Cornish, Devonshire, and 
 similar brown hematites, from 12 to 14 per cent., 
 although, under unfavourable circumstances, the latter 
 *iave been known to lose as much as .26 per cent. 
 
 Gjers' calcining kiln, now largely employed in the 
 
138 METALLURGY OF IRON. 
 
 Cleveland district, is represented in transverse vertical 
 section in Fig. 1. Unlike the massive kilns used in 
 South "Wales, the body or shell 
 is of fire-brick only 1 5 inches in 
 thickness, cased with wrought- 
 iron plates in a similar manner 
 to that now adopted usually 
 in blast furnaces. The dia- 
 meter at the top is 18 feet, at 
 the boshes, or widest part, 
 forming the junction of the 
 two cones 20 feet, and at the 
 bottom 14 feet. The hori- 
 zontal section is everywhere Kg. i.-Gjers' calcining kim. 
 circular. The bottom of the brickwork rests upon a 
 flat cast-iron plate 4 inches thick, which is supported 
 by a number of vertical cast-iron columns 27 inches 
 high, leaving an open space all round between the 
 bottom of the kiln and the floor. The latter is covered 
 in with a cast-iron plate 20 feet in diameter and 2J 
 inches thick, cast in segments, carrying in the centre 
 an upright cone of 8 feet in height and diameter. The 
 total height from the foundation-plate to the filling 
 gallery at the top is 24 feet, and the capacity 5,500 
 cubic feet. The ore remains in the kiln about two 
 days and a half, the amount of fuel required being 
 about 1 ton of coal slack for every 20 tons of ore. 
 The admission of air from the exterior is regulated by 
 a series of holes penetrating the brickwork near the 
 bottom, and a further supply is introduced into the 
 centre by means of a series of radiating flues in the 
 brickwork of the foundation and the hollow in the 
 overlapping part of the central cone. The roasted ore 
 is drawn through the openings between the pillars, 
 
ROASTING OR CALCINATION OF IRON ORES. 139 
 
 being directed outwards by the slope of the interior 
 cone. With larger kilns of similar construction, 34 
 feet high, the consumption of fuel is reduced to 1 ton 
 per 25 tons of ore. 
 
 In the district of Siegen, the kilns used for roasting 
 spathic ores are of cjdindro- conical form, the conical 
 part being placed with its smaller end downward below 
 the cylinder. The average dimensions are : height 
 17 J feet, diameter at the top 5f feet, diameter at the 
 bottom 3J feet, and interior capacity about 500 cubic 
 feet. The bottom of the conical part, which is about 
 3 feet above the level of the ground, is closed by a 
 grate with bars 3 inches apart. A second grate 
 about 2 feet below the first, and parallel to it, is used 
 for starting the fire. 
 
 Before charging, a layer of pine charcoal 4 inches 
 thick is placed upon the upper grate, which is suc- 
 ceeded by alternating layers of ore broken small, and 
 fuel of an inferior quality, such as waste charcoal, 
 breeze, coke or cinders from puddling furnace fires, or 
 coke dust, in the proportion by measure of 40 cubic 
 feet of ore to 8 of fuel, until the kiln is filled to the 
 throat. A wood fire is then lighted on the lower 
 grate, which soon ignites the charcoal on the upper 
 one, and after a time, the coke and cinders mixed 
 with the lower layers of ore. The fire on the lower 
 grate is kept up for three days, the total consumption 
 of wood being about 1J cwt., when the ore at the 
 bottom is found to be sufficiently roasted, and may be 
 withdrawn. This is effected by removing the bars of 
 the upper grate, and allowing the ore to fall out. About 
 one-fourth of the whole contents of the kiln are drawn 
 at a time ; the bars are then replaced, and the kiln is 
 filled with fresh charges, but the measure of fuel is 
 
140 
 
 METALLURGY OF IRON. 
 
 reduced to one-half of that used at first. The next draw- 
 ing takes place twenty-four hours later, and so on for 
 several weeks in succession : one-quarter of the contents 
 may be withdrawn daily. The average time of roasting 
 the charge is, therefore, about four days. 
 
 The admission of air is regulated by draught-holes, 
 with sliding registers placed above the upper grate. 
 
 The construction of a mine kiln using the waste 
 gases of the blast furnace instead of solid fuel is 
 shown in vertical section, Fig. 2, which represents one 
 
 Fig. 2. Swedish gas calcining kiln. 
 
 erected at Safvenas, in Lapland. It consists of a nearly 
 cylindrical shaft 18 J feet high, increasing in diameter 
 from 5 feet at the top to 7 feet at the bottom, made up 
 of three concentric casings, or walls of brickwork. The 
 innermost wall or lining is formed of fire-brick, and is 
 
ROASTING OR CALCINATION OF IRON ORES. 141 
 
 carried upon a cast-iron ring, a ; the second and third 
 are of common, bricks, and divided by a layer of sand. 
 The outer wall, about 2 feet in thickness, is perfo- 
 rated by numerous horizontal channels for the escape 
 of moisture, and is further bound together by hoops of 
 wrought iron. The plan of the base is cylindrical, 
 perforated by five radial passages slightly splayed out- 
 wards, through which the roasted ore is withdrawn, the 
 sides of these passages, as well as the bottom of the 
 kiln, being protected by cast-iron linings. The gas 
 coming from the blast furnace by the wrought-iron 
 tube, by passes into the cast-iron circular main, c, which 
 is provided with ten jets placed at equal distances apart 
 from the base. The necessary amount of air for com- 
 bustion is admitted through the apertures, e, the supply 
 being regulated by a sliding plate covering the mouth 
 of the jet. Higher up is placed a second series of holes, 
 /, through which bars may be introduced for break- 
 ing up lumps in the event of the charge clotting to- 
 gether from overheating. The ores are hard magnet- 
 ite, and schistose or micaceous hematite mixed with 
 quartz : they pass through, without undergoing any 
 very great change, being mainly rendered friable, 
 without alteration in the state of oxidisation of the 
 iron ; but iron pyrites, when present, is almost com- 
 pletely decomposed. 
 
 From 20 to 30 tons of ore are roasted daily, the only 
 fuel employed being a portion of the waste gases of a 
 small charcoal blast furnace. 
 
 At Soderfors a kiln has been recently built on the 
 above principles, with the addition of a conical 
 chimney with a damper, for more perfectly regulating 
 the draught. In order to prevent fusion of the ore } 
 air, at a pressure of J to ^ inch of water, is intro- 
 
142 
 
 METALLURGY OF IRON. 
 
 duced tlirougli a hollow ring at the base of the shaft, 
 provided with 24 small twyers, the supply being 
 taken from the engine that blows the blast furnace. 
 The dimensions are somewhat larger than those given 
 in the preceding example, the shaft being 21 feet high, 
 9 feet in diameter at the base, and 5f feet at the throat ; 
 the chimney is 28 feet high. The daily production is 
 from 35 to 50 tons. 
 
 In roasting spathic ores containing iron pyrites it is 
 necessary to provide as much as possible for the free 
 access of air in order to oxidise the sulphur which is 
 partly volatilised as sulphurous acid, the remainder 
 forming sulphate of protoxide of iron. Fig. 3 repre- 
 
 Fig. 3. Styrian kiln for pyritic ores. 
 
 sents a simple form of pile or annular kiln, adopted at 
 Mariazell, in Styria, for roasting this class of ore. It 
 consists of a series of flat cast-iron rings 1 inch thick. 
 
ROASTING OR CALCINATION OF IRON ORES. 143 
 
 and 9 feet internal diameter, placed one above another. 
 The bottom one is 2 feet wide, and is supported by eight 
 piers of brickwork 12 inches square, and 20 inches 
 high. The succeeding ones, eleven in number, are only 
 1 foot broad, and are kept at a uniform distance of 7 
 inches apart by piers similarly placed, formed of two 
 bricks each. In the centre of the enclosed space is 
 placed a cylindrical brick chimney 2 feet in diameter, 
 having six holes of 3 inches square for regulating the 
 draught in each course ; these holes are made by 
 leaving out alternate bricks in the manner usual in 
 Staffordshire coke heaps. The top of the chimney is 
 covered with a cast-iron plate, carrying a vertical cast- 
 iron pipe for increasing the draught ; at the bottom it 
 is in communication with the external air by a rect- 
 angular flue 2 feet broad and 18 inches deep. A cast- 
 iron water-pipe, provided with numerous small jets, 
 surrounds the kiln at the level of the lower ring. 
 
 The charging is effected in the following manner : 
 a bed of split wood, placed radially on the ground, is 
 covered with a layer of charcoal dust amounting to four 
 tubs of 7f cubic feet each. Upon this comes the first 
 layer of ore, containing 45 barrows of 160 to 180 Ibs. 
 each, and so on in alternate layers in the same propor- 
 tion, till the kiln is filled to the level of the top ring. 
 The wood is lighted all round between the lower pillars. 
 As soon as the fire has burnt through to the top, the 
 drawing of the bottom layer may be proceeded with : 
 this is usually done at intervals of from sixteen to twenty- 
 four hours. About 6 tons of ore may be drawn daily ; 
 the loss of weight is about 20 per cent. 
 
 In order to remove the sulphates, the calcined ore is 
 quenched with water from the main. The large lumps 
 are broken, and it is then exposed to the action of the 
 
144 METALLURGY OF IR.DN. 
 
 air in heaps about 2 feet high, which are repeatedly 
 turned and watered, until all the soluble salts are 
 washed out. 
 
 Experiments made with ores treated in this manner, 
 after eight days' exposure to the air, proved that the 
 sulphur had been sufficiently removed for the pro- 
 duction of iron in the furnace. Formerly, from five to six 
 years' exposure after roasting was required to obtain the 
 same result, which necessitated keeping quantities of 
 about 100,000 tons of ore under treatment, in order to 
 supply the four furnaces in blast. 
 
 The desulphurisation of pyritic ores may also bo 
 effected by the action of steam at a red heat. This 
 method was adopted in Finland, by Nordenskjold, in 
 1843, and has subsequently been used in Silesia and 
 "Westphalia. In the latter district it is applied to the 
 roasting of blackband containing from 1 to 3 per cent, 
 of sulphur. The kiln, which is somewhat similar in 
 form to Fig. 2, is 25 feet high, 6 feet in diameter at 
 the throat, with a conical shaft increasing to 9 feet 
 at 19 feet below the mouth : the remaining height of 
 6 feet is cylindrical. Near the bottom is introduced a 
 wrought-iron pipe 2 inches in diameter, and termi- 
 nating in a conical jet or rose, perforated with nume- 
 rous small holes. The charging takes place in the 
 usual way, upon a bed of kindling wood : no coal is 
 used, as the ore is sufficiently carbonaceous not only to 
 calcine itself, but also a further quantity of magnetic 
 ore smelted at the same place. As soon as the contents 
 of the kiln are red hot, superheated steam at 36 Ibs. 
 pressure is admitted through the conical jet-pipe for a 
 few minutes at a time, at intervals of half an hour, 
 which, acting on the pyrites, gives rise to sulphuretted 
 hydrogen and peroxide of iron. In order that the 
 
Of THE FLUXES USED IN IRON-SMELTING. 
 
 sulphides may not be re-formed in the upper part of 
 the shaft, it is necessary to admit air freely, so that 
 the sulphuretted hydrogen may be resolved into water 
 and sulphurous acid. By this means the whole of the 
 sulphur is almost entirely removed. In a kiln of this 
 kind, 12J tons of magnetic oro and 3f tons of black- 
 band are calcined daily. 
 
 CHAPTER VII. 
 
 OF THE FLUXES USED IN IRON-SMELTING. 
 
 THE general principles upon which the employment of 
 fluxes is based have already been alluded to ia describ- 
 ing the method of assaying by the dry way. In 
 practice very few ores are found to contain earthy in- 
 gredients in proportions sufficient to form readily fusible 
 slags alone, and it therefore becomes necessary to 
 supply the deficiency. This may be done either by 
 mixing ores of dissimilar composition, as, for instance, 
 siliceous with calcareous hematites, or both witii argil- 
 laceous ores in such quantities as shall yield slags of 
 the desired composition, or by the addition of calcareous 
 or aluminous minerals not containing iron. The first 
 of the above methods is undoubtedly to be preferred to 
 the other, as by it we are enabled to form the slag 
 without unnecessarily reducing the percentage of iron 
 in the charge or burden taken as a whole, whereas the 
 addition of fluxes increases the weight of material to 
 be passed through the furnaces for the same produce of 
 metal, but it can only be carried out in districts having 
 a, large and varied command of minerals. As a rule, 
 therefore, a combination of both methods is used, the 
 
 ii 
 
146 
 
 METALLURGY OF IRON 
 
 best mixture of ores obtainable being supplemented bj 
 the addition of earthy minerals. 
 
 The principal flux employed by the iron smelter is 
 carbonate of lime, in the form of limestone, which is 
 usually obtained from a neighbouring quarry. The 
 best varieties are those containing the largest amount 
 of carbonate of lime, but alumina and iron may be 
 present advantageously. In the latter case limestones 
 often pass insensibly into calcareous hematite or 
 magnetite, which form excellent mixtures with more 
 siliceous ores of the same class. Yery fossiliferous 
 limestones often contain notable amounts of phosphoric 
 acid and iron pyrites, and are to be avoided. Dolomitic 
 or magnesian limestones are less generally useful than 
 more purely calcareous varieties, as the fusibility of 
 slags is diminished by the addition of magnesia beyond 
 very moderate quantities. 
 
 Rich iron ores occurring in crystalline rocks, such 
 as those of Sweden, Norway, and North America, are 
 often accompanied by limestones containing silicates 
 of lime and magnesia of a low degree of silication, 
 such as pyroxene, hornblende, garnet, idocrase, chlorite, 
 all which may be regarded as ready-formed slags. The 
 use of these substances as fluxes is usually attended 
 with a great economy of fuel. Such ores are known 
 in Sweden as self-gaejende, i.e. self-going or self-fluxing. 
 A somewhat similar effect may be obtained by the use 
 of blast-furnace slag a second time, if it be sufficiently 
 basic to carry an extra dose of silica ; but this is rarely 
 done except under pressure of adverse circumstances. 
 Percy relates a case of this kind as having occurred in 
 South Wales, where slags were used a second time 
 without injuring the quality of the iron produced, 
 when the supply of limestone was temporarily cut off. 
 
OP THE FLUXES USED IN IRON- SMELTING. 
 
 147 
 
 The following table shows the average composition 
 of some of the commoner varieties of Limestone used 
 by iron masters in England and Wales : 
 
 ANALYSES OF LIMESTONES USED IN ENGLISH IRON WORKS. 
 
 
 I. 
 
 n. 
 
 m. 
 
 IV. 
 
 V. 
 
 Carbonate of 'lime . 
 
 97-31 
 
 95-26 
 
 97-54 
 
 89-36 
 
 96-15 
 
 Carbonate of magnesia 
 
 1-00 
 
 2-21 
 
 0-90 
 
 0-97 
 
 1-32 
 
 Carbonate of protoxide of 
 
 
 
 
 
 
 iron .... 
 
 0-62 
 
 
 
 
 
 3-38 
 
 
 
 Alumina and peroxide \ 
 
 
 
 
 
 
 of iron > 
 
 1-27 
 
 2-98 
 
 1-35 
 
 6-00 
 
 3-20 
 
 Silica ) 
 
 
 
 
 
 
 Organic matter 
 
 0-20 
 
 
 
 
 
 
 
 
 
 "Water .... 
 
 
 
 
 
 
 
 0-43 
 
 
 
 
 100-40 
 
 100-45 
 
 99-79 
 
 100-14 
 
 100-67 
 
 No. I. Silurian limestone, Dudley. Used in South Staffordshire. 
 
 II. Carboniferous limestone, Harmby, Durham. Used in Cleve- 
 land. 
 
 III. Permian limestone, Raisby Hill, Durham. Used in Cleveland. 
 
 IV. Oolitic limestone, Wellingborough. Used in Northampton- 
 shire. 
 
 V. Chalk, after deducting 21 per cent, of water. Used in 
 Cleveland. 
 
 In the Lancashire and Cumberland hematite district, 
 where the rich red ores of TJlverstone and "Whitehaven 
 are smelted alone, argillaceous fluxes are necessary in 
 addition to limestone. For this purpose the shale of 
 the coal measures is generally added; but latterly a 
 peculiar variety of brown hematite, remarkable for 
 containing a large quantity of free alumina, has come 
 into use in these districts, and also in South "Wales. 
 This substance is known as " Belfast Aluminous Ore." 
 A somewhat similar mineral, called Bauxite, found at 
 Baux, in the south of France, is now used to a con- 
 siderable extent as an ore of aluminium. 
 
 H2 
 
148 
 
 METALLURGY OF IRON 
 
 ANALYSES OF ALUMINOUS ORES AND FLUXES. 
 
 
 I. 
 
 ir. 
 
 in. 
 
 IV. 
 
 Silica ..... 
 
 61-91 
 
 9-75 
 
 9-87 
 
 2-8 
 
 Alumina . . 
 Peroxide of iron , 
 Protoxide of iron . 
 Lime . . . 
 Magnesia 
 Potash 
 Soda . 
 
 21-73 
 
 4-73 
 0-09 
 0-59 
 3-16 
 0-25 
 
 27-95 
 3o-91 
 6-57 
 0-60 
 0-20 
 0-49 
 
 34-57 
 27-93 
 5-08 
 0-91 
 0-62 
 
 57-4 
 25-5 
 
 0-2 
 
 Titanic acid . 
 Volatile 
 
 7'43 
 
 18-60 
 
 3-51 
 19-36 
 
 3-1 
 11-0 
 
 
 99-89 
 
 100-12 
 
 101-85 
 
 100-0 
 
 No. I. Coal measure shale from the neighbourhood of Manchester. 
 
 Frankland. 
 
 II. Belfast aluminous ore. Tookey. 
 III. Another sample of the same ore. 
 IV. Bauxite, from Baux, in the south of France. Bell. 
 
 Caustic lime is sometimes used instead of limestone, 
 and produces a certain economy of fuel, as the local 
 cooling, owing to the absorption of heat in the blast 
 furnace consequent on the expulsion of the carbonic acid, 
 is done away with. Comparative experiments on this 
 point have been made at Ougree, in Belgium, and 
 Konigshutte, in Silesia. In the former case, 26 per 
 cent, of lime replaced 40 of limestone, and the pro- 
 duction of metal was increased 2*3 per cent., with a 
 saving of 1-6 per cent, of coke. In the latter the 
 saving was 2 '85 per cent., and the increase of produc- 
 tion 3-1 per cent. It is of course necessary to use the 
 lime as soon as possible after burning, in order to 
 prevent it taking up moisture from the air. 
 
 Forge and Mill Cinders^ l will be convenient to 
 notice these substances, which play a very important 
 part in the economy of modern iron works, before 
 leaving the subject of iron ores, although, strictly 
 speaking, they cannot be classified with them, but are 
 
OF THE FLUXES USED IN IRON-SMELTING. 149 
 
 lather to be considered as waste products, which, are 
 produced and regularly economised on a very largo 
 scale. When melted pig iron is exposed to the oxidising 
 action of the air, its combined silicon is oxidised, with 
 the formation of tribasic silicate of protoxide of iron, 
 which is very fusible, and is capable of taking up a 
 further amount of iron, probably in the form of 
 magnetic oxide. The same thing takes place when 
 wrought iron is heated in contact with silica, at a 
 welding temperature. It will subsequently be shown 
 that the slags or cinders produced in the various opera- 
 tions of refining, puddling, and reheating, performed 
 in the conversion of cast into malleable iron, are of this 
 composition. The amount of iron contained varies 
 from 40 to 75 per cent., and in this respect cinders 
 might be considered as equal to the richest iron ores, 
 were it not that practically the whole amount of 
 phosphorus contained in the pig iron operated upon is 
 also taken up, as well as more or less sulphur, so that 
 in. reality their use in the blast furnace tends to de- 
 teriorate the quality of the metal produced, when 
 entering into the charge beyond a certain proportion. 
 
 The chief reason, however, for the deterioration is 
 to be found in the ready fusibility and comparatively 
 Limcult reducibility of the cinders, which, when added 
 the charge in the blast furnace, are apt to melt and 
 in down into the hotter part of the furnace above 
 ie hearth, where the reduction of iron and silicon 
 ikes place simultaneously. Only a portion of the 
 silicate, however, is so reduced : the remainder, passing 
 into the blast-furnace slag, produces the so-called black 
 or scouring cinder, which not only acts injuriously 
 upon the siliceous matters of the hearth, but prevents 
 the formation of cast iron at a maximum of carbonisa- 
 
150 METALLURGY OF IRON. 
 
 fcion. The result is therefore an inferior description of 
 white iron, usually known as cinder pig, together with 
 the loss of a considerable quantity of iron in the slag, 
 which sometimes contains nearly 20 per cent, of prot- 
 oxide of iron, 
 
 The purest class of cinders are those from the re- 
 heating or welding furnace, being freer from sulphur 
 and phosphorus than those obtained in puddling. 
 Various methods have been suggested for overcoming 
 the difficulties attendant on the smelting of cinders, 
 such as subjecting them to a preliminary calcination, 
 or combining them with lime and small coal in order 
 to effect the reduction at a lower temperature. Of 
 these methods only the former has been generally 
 adopted. When silicate of protoxide of iron is roasted, 
 either in heaps or kilns, with a free access of air it is 
 decomposed, with a separation of silica : the protoxide of 
 iron, absorbing oxygen, passes into the state of peroxide, 
 or magnetic oxide, producing a very refractory sub- 
 stance, which is employed, under the name of " bull- 
 dog," for lining the hearths of puddling furnaces. Its 
 infusibillty is due to the fact that silica and peroxide of 
 iron are both infusible, and do not combine together 
 when exposed to a high temperature in an oxidising 
 atmosphere. When the bulldog is produced from 
 puddling-furnace cinders containing phosphorus in 
 quantity a partial liquation takes place, and a fusible 
 slag, known as bulldog slag, separates, carrying down 
 with it a considerable portion of the phosphorus. 
 Sulphur, when present, is almost entirely removed 
 during the roasting, being converted into sulphate of 
 iron, which forms a crust over the outer surface of the 
 heap, and may be washed out with water, or decom- 
 posed by further heating. It will readily be seen 
 
OF THE FLUXES USED IN IRON- SMELTING. 151 
 
 that when the iron is peroxidised it is in a much, more 
 favourable condition for treatment in the blast furnace, 
 and the cinders may then be regarded as equivalent to a 
 siliceous hematite. 
 
 In Lang's method of preparing puddling and other 
 forge cinders for the smelting furnace they are finely 
 powdered, and mixed with milk of lime and coal slack, 
 or charcoal dust, into a paste, which, when dry, forms 
 a hard mass, and may be broken into lumps, having 
 sufficient coherence to stand the pressure of the blast 
 furnace without crushing. At Store, in Carniola, 
 where this process was introduced in 1861, sixty- 
 six parts of reheating furnace cinder, mixed with 22 
 parts of lime and 12 parts of charcoal dusfc, were 
 smelted in a cupola without any addition of ore, and 
 produced mottled pig iron of good quality. Several 
 analyses of pig iron so produced have been published, 
 but the composition of the cinder operated upon is not 
 given. 
 
 A somewhat similar process has been proposed by 
 Minary and Soudry. The cinder, in a finely- divided 
 state, is mixed with caking coal slack, and converted 
 into coke in the ordinary way. According to the state- 
 ments of the inventors, the protoxide of iron in the 
 cinder is said to be reduced to the metallic state by the 
 gases given off during the coking, at a temperature 
 sufficiently low to be without effect upon the silica ; at 
 the same time both phosphorus and sulphur are 
 eliminated as phosphuretted and sulphuretted hydrogen. 
 The coke produced is intended to be used in the blast 
 furnace for smelting ores. In order to obtain it 
 sufficiently coherent, it is necessary to keep the mixture 
 of slack and cinders with certain proportions. The 
 best results were obtained at Givors, with 40 of the 
 
152 METALLURGY OF IRON. 
 
 latter to 60 of the former, which gave a coke containing 
 from 20 to 25 per cent, of metallic iron ; but the propor- 
 tions might be reversed without consuming any of the 
 fixed carbon of the fuel in the reduction, which is effected 
 entirely by the volatile products. The removal of the 
 uncombined silica must, of course, be provided for by 
 the addition of a proportionate quantity of limestone 
 over and above that required by the ore in the blast 
 furnace. 
 
 The above statements are, to a certain extent, in 
 opposition to the results obtained by Percy and 
 Richardson, who found that the dibasic silicate of 
 protoxide of iron could not be entirely reduced to the 
 metallic state when heated with an excess of carbon, two- 
 thirds only of the protoxide being separated, leaving 
 behind a higher silicate (2 FeO 3 SiO 2 ), which resisted 
 further change. This result can only be obtained with 
 chemically pure tribasic silicate, such as is prepared by 
 fusing pure peroxide of iron with quartz sand, whereas 
 the cinders produced in puddling or heating furnaces, 
 always contain a sufficient proportion of earthy bases 
 to allow the last atom of iron to be set free. 
 
 The addition of fluxes in the blast furnace is regu- 
 lated by several considerations. When the ores are of 
 good quality, the chief point to be considered, is the 
 production of the most fusible slag with the smallest 
 addition of non-ferriferous matters ; this is more espe- 
 cially the case with charcoal furnaces. When mineral 
 fuel is used, however, it is necessary to form a slag 
 that is capable of absorbing sulphur, which would 
 otherwise be taken up by the iron, and for this purpose, 
 a larger quantity of flux is used than that indicated 
 by theory as giving the most fusible product. 
 
 The fusibility of silicates depends chiefly upon their 
 
OF THE FLUXES USED IN IRON-SMELTING. 153 
 
 composition, and, according to Plattner, increases with 
 the increase of silica : thus for the same base the mono- 
 basic 2 RO SiO 2 and sesquibasic RO SiO 2 forms are 
 more fusible than the dibasic, containing 2 RO.SiO 2 , 
 or the subsilicate, 4 RO. SiO 2 . For the same compo- 
 sition, silicates containing one base are less fusible than 
 those containing two or more. The following is the 
 observed order of fusibility in the simple silicates : 
 
 Silicate of Alumina .... melts at 2,400 C. 
 
 Magnesia .... 2,200 2,250 
 
 Baryta 2,100 2,200= 
 
 Lime 2,100 2,150 
 
 Protoxide of Iron , 
 
 Manganese} W* 
 
 Of double silicates of similar atomic composition, 
 those containing both protoxide and sesquioxide bases 
 are more fusible than those having both bases of the pro- 
 toxide type, the order of fusibility being as follows : 
 
 Silicate of Baryta and Lime melts at 2,100 C. 
 
 Alumina 2,050 
 ,, Lime ,, Magnesia ,, 2,000 
 Alumina 1,918 3,950 
 
 The most fusible of the triple silicates likely to be 
 produced in iron-smelting are those containing alumina, 
 lime, and protoxide of iron, or manganese. Silicates of 
 potash and soda, or of protoxide of lead, are among the 
 most fusible ; but with these we are not at present con- 
 cerned. 
 
 The slags of blast furnaces may be regarded as 
 silicates, whose composition ranges between the follow 
 ing limits : 
 
 I. CaO. SiO 2 + A1 2 3 . 3 SiO 2 ; and 
 II. 2 CaO. SiO 2 + 2 A1 2 3 . 3 SiO 2 . 
 H3 
 
154 METALLURGY OF IRON. 
 
 Those of charcoal furnaces are mixtures in indefinite 
 proportions of both silicates, while those produced with 
 coke or coal are more basic, and approach more nearly 
 in composition to No. II. 
 
 In the first of the above formulae the oxygen of 
 the silica is double that of the bases taken together, 
 corresponding to the composition HO. SiO 2 , or that 
 of augite ; while in the second both bases and silica 
 contain equal amounts of oxygen, giving the formula 
 2 KO. SiO 2 , or that of olivine. 
 
 As a portion of the lime may be, and usually is, 
 replaced by other protoxide bases, and also alumina 
 may be partially substituted for silica, it is evident 
 that these general expressions may be made to include 
 substances differing widely in qualitative composition. 
 The following are the maximum and minimum limits 
 of the chief constituents of blast-furnace slags derived 
 from the examination of a large number of analyses : - 
 
 Mia. Max. 
 
 Silica. .3ii eJlwsi . 20 . .72 percent. 
 Alumina : . ,,. . . .30 
 Lime . /* . ,,. . . . 60 ,, 
 Protoxide of iron . . .26 ,, 
 ,, manganese . .34 
 
 Magnesia , - . o . "V 34 ,, 
 Baryta ; {1 ' J H 1 ' 1 "' . . 'V" 8-2 
 Soda . "v~ ? ' ,-!.- . . .11-3 
 Potash . iV . . ''^ - 4-3 
 Bodemann gives the following formula for the most 
 fusible silicate of lime and alumina : 
 4 (CaO. SiO 2 ) + 3 (APO 3 . 3 SiO 2 ), containing, per cent., 
 Silica, 56 ; Lime, 30 ; Alumina, 14. 
 
 The following are a few examples of slags produced 
 under different conditions of working. The composi- 
 
OF THE FLUXES USED IN IRON-SMELTING. 
 
 155 
 
 tion of the slags from furnaces in different localities, 
 and under dissimilar conditions of working, is illustrated 
 in the following table, as far as it can be done with 
 such a small number of examples : 
 
 ANALYSES OF BLAST FURNACE SLAGS. 
 
 
 I. 
 
 II. 
 
 III. 
 
 IV. 
 
 V. 
 
 VI. 
 
 VII. 
 
 Silica 
 
 38-48 
 
 43-07 
 
 31-46 
 
 27-68 
 
 42-96 
 
 61-06 
 
 40-95 
 
 Alumina . 
 
 15-13 
 
 14-85 
 
 8-50 
 
 22-28 
 
 20-20 
 
 5-38 
 
 8-70 
 
 Lime 
 
 32-82 
 
 28-92 
 
 52-00 
 
 40-12 
 
 10-19 
 
 19-81 
 
 30-36 
 
 Protoxide of 
 
 
 
 
 
 
 
 
 iron . 
 
 0-76 
 
 2-53 
 
 0-79 
 
 0-80 
 
 19-80 
 
 3-29 
 
 0-60 
 
 Protoxide of 
 
 
 
 
 
 
 
 
 manganese . 
 
 1-62 
 
 1-S? 
 
 2-38 
 
 0-20 
 
 1-53 
 
 2-63 
 
 2-18 
 
 Magnesia . 
 
 7-44 
 
 5-87 
 
 1-38 
 
 7-27 
 
 2-90 
 
 7-12 
 
 16-32 
 
 Sulphide of cal- 
 
 
 
 
 
 
 
 Sulphur. 
 
 cium . . 
 
 2-22 
 
 1-90 
 
 2-96 
 
 2-00 
 
 1-32 
 
 
 
 0-34 
 
 Alkalies . 
 
 1-92 
 
 1-84 
 
 
 
 
 
 1-10 
 
 
 
 0-32 
 
 Phosphoric acid 
 
 0-15 
 
 
 
 
 
 
 
 
 
 
 
 0-10 
 
 
 100-54 
 
 100-35 
 
 99-47 
 
 100-35 
 
 100-00 
 
 99-29 
 
 99-87 
 
 No. I. From Dowlais, produced when making grey iron. Kiley. 
 II. produced with white iron. Riley. 
 
 III. Kirkless Hall, Wigan, produced with grey Bessemer 
 
 iron, disintegrates in the air. 
 
 IV. Clarence, Durham, from Cleveland ores. Bell. 
 
 V. Cwn Celyn, South Wales, scouring cinder. Noad. 
 VI. Gosberg, Sweden. Sjogren. 
 VII. Neuberg, Styria, produced with grey iron. Kiippel- 
 
 It occasionally, but rarely, happens in the smelting of 
 spathic ores, that slags are produced entirely free from 
 lime. The following are examples of this kind : 
 
 
 L 
 
 II. 
 
 III. 
 
 Silica 
 Alumina 
 Protoxide of iron .... 
 Protoxide of manganese 
 
 49-57 
 9-00 
 0-04 
 25-84 
 15-15 
 
 48-39 
 6-66 
 0-06 
 33-96 
 10-22 
 
 37-80 
 2-10 
 21-50 
 29-20 
 8-60 
 
 
 0-08 
 
 0-08 
 
 0-02 
 
 
 
 
 
156 METALLURGY OF IKON. 
 
 No. I. From Siegen, produced with grey iron. Karsten. 
 II. ,, t spiegeleisen. Karsten, 
 
 III. Styria, white iron. Von Mayrhofer. 
 
 When tlie fusibility of a slag is reduced, by the 
 addition of lime in excess, the iron will be highly 
 carburetted, and the greater amount of sulphur will be 
 taken up by the slag in the form of sulphide of cal- 
 cium. Other things being equal, the iron will be grey 
 if the slag is refractory, and white if it is very fusible. 
 The reason of this is apparent when we consider that 
 the iron may be reduced and carburetted, but cannot 
 separate from the earthy matters till these have melted 
 into slag ; if, therefore, the latter are very fusible, the 
 metal which melts at a still lower temperature runs 
 together, or falls through the region of the boshes 
 and hearth, where the temperature is highest, without 
 being exposed for any length of time to the energetic 
 reducing agencies prevailing at and near the interior. 
 If, on the other hand, the finely- divided particles of 
 metal are kept from coalescing by the more refractory 
 character of the slag, it will be subjected to a long- 
 continued heating in a region favourable to the accu- 
 mulation of carbon and silicon in the highest degree, 
 and it is to the presence of the latter element that the 
 greyness of pig iron is in part, at least, due. 
 
 The power of taking up sulphur is also imparted to 
 slags by protoxide of manganese, as well as lime, a 
 property that receives an important application in 
 the manufacture of spiegeleisen from manganesiferous 
 spathic ores. 
 
 Protoxide of iron increases the fusibility of slags, 
 communicating at the same time a dark green or black 
 colour, as is seen in the so-called scouring in black 
 cinders which are produced when a furnace is working 
 
OF THE FLUXES USED IN IRON-SMELTING. 157 
 
 with a heavy burden, or increased charges of ore and 
 fluxes in proportion to the fuel. 
 
 These slags are accompanied by the production of 
 white iron, from the reduction of a portion of the 
 protoxide of iron in the molten silicate when brought 
 into contact with the bath of cast iron in the hearth, at 
 the expense of the carbon in the molten metal. With 
 silicate of protoxide of manganese, however, this re- 
 action does nofc take place, owing to the very high 
 temperature required for the reduction of protoxide 
 of manganese to the metallic state. 
 
 The physical character of slags, such as colour, 
 texture, fluidity, &c., varies with their composition and 
 the working condition of the furnace, so that it is not 
 possible from inspection alone to determine the charac- 
 ter of the metal produced, except after considerable 
 experience of the individual furnace ; and the relation 
 between slag and metal in one district may be totally 
 different in another. De Yathaire makes the following 
 general observations on this point, which, of course, 
 must be taken as applicable only within wide limits : 
 
 Slags produced from furnaces working hot i.e. with 
 light burden when the reducing power is at a maxi- 
 mum, and grey iron is made, are usually white or 
 grey. Owing to the total amount of iron being re- 
 duced, in the special case of the ores containing man- 
 ganese, an amethystine tint is often observed under 
 these conditions, especially in charcoal furnaces smelt- 
 ing hematite or non-aluminous ores. 
 
 Black slags, on the other hand, correspond to heavy 
 burden, and a comparatively reduced temperature, when 
 the furnace is said to be working cold, or with less fuel 
 as compared with the weight of the charge smelted. 
 
 The vitreous character and fluidity of slags increaso 
 
158 METALLURGY OF IRON. 
 
 in proportion to the amount of silica. A porcelanic or 
 opalescent character is generally indicative of a con- 
 siderable amount of alumina. Those produced in the 
 smelting of coal-measure clay ironstones are often of 
 this character, showing an alternation of light yellowish 
 and dark green or blue bands and stripes. Slow cool- 
 ing has a tendency to produce devitrification or crystal- 
 lisation, so that it often happens that the same slag forms 
 a perfect glass when suddenly solidified, but becomes 
 opaque or porphyritic, with distinct crystals interspersed 
 through a vitreous base, when cooled very gradually. 
 
 When slags containing sulphides of calcium, barium, 
 and manganese, such as are commonly produced when 
 sulphur is present in the fuel, are allowed to flow 
 over damp ground, in smelting with coke, steam is 
 forced through the molten mass, which, in its passage, is 
 decomposed by the sulphides and poly sulphides, with 
 the production of sulphuretted hydrogen. This in its 
 turn burns on coming in contact with the air, giving 
 rise to sulphurous acid gas. If, however, water be 
 thrown upon the surface of the slag, the sulphuretted 
 hydrogen evolved is prevented from igniting, escapes 
 unaltered, and may be recognised by its unpleasant 
 odour. The reactions are as follows, according to 
 whether a neutral or poly- sulphide of calcium be 
 present : 
 
 CaS + H 2 = CaO + SH 2 . 
 
 CaS 5 + 3 H 2 = CaO + 3 H 2 S + SO 2 + S. 
 In the latter case the decomposition is more complex, 
 being attended with the formation of sulphurous acid, 
 sulphuretted hydrogen, and free sulphur. Under 
 ordinary conditions, however, the two latter products 
 would unite and burn to sulphurous acid. This is pro- 
 
OF THE FLUXES USED IN IRON-SMELTING. 159 
 
 bably the cause of the strong odour of this gas usually 
 produced by the slags escaping from a coke furnace 
 working very hot. 
 
 When lime is present in large quantity, the fracture of 
 the slag is usually of a dull stony character. Those of the 
 Cleveland and Lancashire hematite furnaces are of this 
 kind. A very large excess of this base causes the slag 
 to fall to pieces when exposed to a moist atmosphere 
 after cooling, in the same way as caustic lime, forming 
 a powder which may be employed in making cement 
 or mortar for building purposes. 
 
 In many of the small iron works of Germany the 
 slags are subjected to the processes of stamping and 
 washing, in order to recover any entangled shots of 
 gietal, which are afterwards returned to the furnace. 
 
 As a general rule, steady and continuous flowing, a 
 somewhat viscid fluidity, and a slow passage from the 
 liquid to the solid state, are characteristic of the slags 
 produced from furnaces working hot. Scouring slags, 
 on the other hand, run as liquid as water, but solidify 
 in crusts rapidly, without passing through the plastic 
 state. 
 
 Slags produced from manganesiferous hematites are 
 of the usual manganese, violet, or amethystic tint in 
 the vitreous portions, but when blown up by gases, the 
 colour disappears, with the production of a pearly- 
 white pumice-like body. When the same furnaces are 
 burdened for white iron the slags become dark green, 
 and of an almost pasty consistency. 
 
 In addition to the colours produced by metallic 
 oxides, such as bottle-green or black by protoxide of 
 iron, violet by protoxide of manganese, yellow or 
 brownish green by protosulphide of manganese, 
 others, especially shades of blue, are common in slags ; 
 
160 METALLURGY OF IOBN. 
 
 but it is not clearly made out what the colouring agent 
 is in such cases. Thus a bright sky-blue tint, often 
 seen in Swedish slags, has been variously attributed to 
 vanadium, titanium, and sulphide of sodium. Miiller 
 considers the blue in coke slags to be due to sulphide of 
 manganese. Silicate of zinc is also stated to produce 
 green and blue tints. 
 
 CHAPTER VIII. 
 
 OF THE BLAST FURNACE AND ITS ACCESSORIES. 
 
 IT has already been stated that in the early days of 
 iron-smelting the only merchantable product was bar 
 or malleable iron obtained directly from the ore ; cast 
 iron being a subsequent discovery, consequent upon the 
 employment of larger furnaces and higher tempera- 
 tures in the treatment of more refractory minerals. In 
 process of time, it was found that the production of cast 
 or pig metal, as an intermediate stage in the manufac- 
 ture of malleable iron, was attended with advantages 
 not possessed by the older method, so that at present it 
 is followed exclusively ; the latter being confined almost 
 entirely to a small and constantly diminishing area in 
 Europe, besides being more extensively practised in 
 Africa and India. 
 
 The subject, therefore, naturally divides itself into 
 two main heads : 
 
 I. Direct method, or extraction of malleable iron 
 from the ore, and 
 
 II. Indirect method, or production of pig iron from 
 the ore, and subsequent conversion into malleable iron 
 by some form of finery process. 
 
 The difference between the two processes is mainly 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 161 
 
 duo to the height of the furnace. In the direct method, 
 where a low charcoal hearth or forge is used, a portion 
 of the ore is reduced to the metallic state at a com- 
 paratively low temperature, while another part combines 
 as protoxide with any silica that may be present, form- 
 ing a highly fusible and basic slag, into which the 
 reduced spongy mass sinks, any excess of carbon taken 
 up being removed by the oxidising agency of the slag, 
 aided by the blast which is introduced through an in- 
 clined nozzle or twyer, so as to impinge directly upop 
 the metallic bath. 
 
 On the other hand, the furnace used for the produc 
 tion of cast iron is mainly distinguished by its height, 
 and may be described in general terms as a conical 
 hearth, whose walls are continued upwards into a 
 chimney or stack of increasing but variable section; 
 the blast-nozzle being laid horizontally instead of in 
 an inclined position. The height of the upper portion, 
 i.e. above the twyer level, may be from ten to twenty 
 times as great as that below, or hearth proper. When 
 the furnace is at work, or, as it is technically termed, 
 in blast, it is kept filled to the top or throat with alter- 
 nate layers of fuel, ore, and flux, the latter being mixed 
 in proper proportions to produce the most fusible com- 
 binations of the earthy matters, a constant stream of 
 air being maintained through the twyers, at a sufficient 
 pressure to pass freely through the contents of the 
 furnace. Part of the incandescent fuel subjected to the 
 blast is completely consumed, burning to carbonic acid 
 with a development of the maximum of heat, whereby 
 the matters immediately adjacent are melted, and fall 
 into the hearth, where they separate by liquation into 
 metal and slag ; the latter, being specifically lighter, 
 rises to the surface, and protects the former from the 
 
162 METALLURGY OF IRON, 
 
 decarburising action of the blast. The carbonic acid 
 formed in the first instance, encountering fresh fuel, is 
 reduced to the state of carbonic oxide, a, process that is 
 attended with a great absorption of heat, so that the 
 region in which a temperature sufficiently high for the 
 fusion of metal and slag prevails does not exterud more 
 than a very short distance from the point of intro- 
 duction of the air. The carbonic oxide so produced, 
 and the unaltered nitrogen of the air, when brought in 
 contact with an oxide of iron at a red heat, is again 
 oxidised to carbonic acid, with the simultaneous pro- 
 duction of metallic iron, which becomes carburetted by 
 further contact with carbonaceous matters in its descent 
 towards the hearth. 
 
 The alternate production of carbonic acid and carbonic 
 oxide, by the reciprocal action of carbon and oxides of 
 iron upon the gases, is continued in the upper part of 
 the furnace as long as the temperature remains suffi- 
 ciently high, the quantity of the former gas being 
 augmented by the decomposition of the limestone flux 
 generally used. Ultimately, however, a sufficient 
 amount of carbonic oxide remains in the so-called 
 waste gases, either to form a great body of flame at 
 the throat of the furnace when the current is allowed 
 to flow freely into the air, or a valuable fuel, yielding 
 sufficient heat for all the accessory operations of the 
 furnace, when collected and utilised. 
 
 The shaft of the blast furnace may, therefore, be 
 considered as combining within itself, and performing 
 the functions of, several distinct furnaces ; thus the 
 hearth is devoted entirely to fusion, while the middle 
 region is essentially a concentration chamber, and the 
 top parts, when raw fuel and flux are used, combine 
 the functions of a limekiln with those of a coke oven. 
 
OF THE BIAST FURNACE AND ITS ACCESSORIES. 163 
 
 Taken as a whole, therefore, the reactions in the 
 manufacture of pig iron are more complex than those 
 of the open-fire process of making malleable iron 
 direct from the ore ; but, as the latter is only one out 
 of many methods by which the same product is 
 obtained, it will be more convenient to defer its 
 consideration, and commence with a description of the 
 former. 
 
 Of Blast Furnaces. In its original, or what may be 
 considered typical form, the blast furnace consists of a 
 shaft or chamber formed of two truncated cones, joined 
 by their bases. The upper and more acute of the two 
 cones is placed upright, and is known as the stack, 
 while the lower and more obtuse one is inverted : the 
 line of junction forming the widest part of the furnace is 
 called the boshes, possibly a corruption of the German 
 bauch. Sometimes the lower cone is continued down 
 to the level of the ground, but more generally the lower 
 part of the furnace is enlarged, forming what is known 
 as the hearth, in which the molten materials collect 
 below the level of the twyers or pipes through which 
 the blast is introduced. 
 
 In France, the space between the twyers and the 
 broadest part, or top, of the boshes is known as the 
 laboratory or working place (ouvrage). 
 
 The top, or throat, of the furnace is surrounded by a 
 platform for the convenience of charging, and is in 
 many cases covered by a short cylindrical chimney, 
 which leads off the flame escaping at the throat ; this 
 portion of the furnace is known as the tunnel head. 
 
 In the newer forms of furnaces, the conical or 
 spindle-shaped body and cylindrical hearth, with 
 their sharply- contrasted divisions, are, for the most 
 part, superseded by more flowing forms, the straight 
 
16 i METALLURGY OF IRON. 
 
 elopes of the sides being converted into curves, giving a 
 more or less barrel- shaped outline to the stack. The 
 same terms are, however, alike applied to the different 
 parts, the boshes being taken as indicating the widest 
 part of the stack, and the hearth that lying below the 
 twyers. 
 
 It will be beyond the province of an elementary 
 sketch like the present to enter into elaborate details 
 of the construction of blast furnaces ; only some of the 
 leading points will be noticed in the following order : 
 
 I. External form and construction. 
 
 II. Details of the interior lining, or working parts. 
 
 III. Construction of the hearth and furnace top. 
 IY. Accessory apparatus, such as lifts, blast engines, 
 
 and stoves. 
 
 V. Methods of collecting waste gases. 
 
 The construction of blast furnaces varies very con- 
 siderably in different localities, in regard to size and 
 proportion of parts to each other, as well as material 
 employed. In the early days of pig-iron manufac- 
 ture, when a square horizontal section was in gene- 
 ral use, the external form was usually that of a 
 square base, pyramidal tower, tapering uniformly from 
 the ground upwards, which became modified, on the 
 introduction of the circular stacks, to a conical or cylin- 
 drical form, the lower portions near the ground, and 
 surrounding the hearth, still retaining the square base. 
 Both of the above forms are characterised by extremely 
 massive construction, the lower parts, or stack pillars, 
 forming solid four-sided blocks of masonry, braced with 
 iron rods, and united by cylindrical arches into the 
 so-called twyer houses, a complete circular passage 
 being usually formed through the mass of the pillars. 
 When the whole furnace is of rectangular section it is 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 165 
 
 bracod by a similar system of tie rods through the 
 entire height, but in conical or cylindrical forms iron 
 hoops, placed at short distances apart, are used for the 
 same purpose. "With every increase of size the massive 
 character of the external casing of the blast furnace has 
 diminished by the reduction of the mass of masonry, 
 and the substitution of cast and wrought iron whenever 
 it is possible to do so. Thus in many modern English 
 furnaces the old stack pillars and twyer houses" have 
 
 Fig. 4. Swedish charcoal blast furnace, vertical section on line AB, Fig. 5. 
 
 been replaced by cast-iron columns or standards, ar- 
 ranged in a circle, whose entablature is a cast-iron 
 ring, carrying the whole of the superstructure, or stack, 
 so that the hoarth casing, instead of being accessible 
 
166 
 
 METALLURGY OF IRON. 
 
 only at the twyers, is now freely exposed all round. In 
 like manner, the old solid stack casing of masonry and 
 hooping has given place to a cylinder of wrought-iron 
 plates riveted together. The latter class are known as 
 cupola furnaces, from their resemblance to the common 
 iron-founder's furnace of the same name. 
 
 Examples of these different forms of construction may 
 be seen in almost every iron-making district. The 
 
 Fig. 5. Swedish charcoal blast furnace plan at E P, Eg. 4. 
 
 older kinds, with massive stacks, are, as might be ex- 
 pected, to be found chiefly in the older districts, such 
 as South Wales, Staffordshire, and Scotland ; while in 
 the newer furnaces of the north-eastern counties and 
 Lancashire, the iron-jacketed cupola type is more com- 
 monly seen. 
 
 Figs. 4 and 5, which are the section and plan of a 
 small charcoal blast furnace at Safvenas, in Lapland, 
 may be taken as an example of the more massive con- 
 struction, with square pillars and a round stack, while 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 167 
 
 Fig. 6 represents the cupola form of furnace, being the 
 
 section of a large coke fur- 
 nace, smelting hematite, at 
 Barrow-in-Furness, Lanca- 
 shire. The other points in 
 the construction of both these 
 furnaces will be referred to in 
 the sequel. They are placed 
 here merely as types of con- 
 struction. 
 
 In some of the furnaces of 
 Sweden and Finland, which 
 are of comparatively small 
 dimensions, the outer casing 
 is formed by a crib- work of 
 wood, like a log hut, the in- 
 termediate space between it 
 and the interior furnace stack 
 being filled in with earth. 
 
 Construction of the working 
 Parts of the Furnace. The 
 shaft, or stack, of the fur- 
 nace, i.e. the upper part 
 above the boshes, is constructed at the same time as 
 the casing. It is now invariably formed of fire-bricks, 
 which are moulded to the proper curve of each ring. 
 The thickness of the shaft or ring wall is about 15 or 
 18 inches, the joints being brought to a fine face and 
 set in fire-clay. A second wall is, in the more massive 
 class of furnaces, placed immediately outside the first ; 
 this may be either of common or seconds fire-brick, 
 and. set in cement; outside of all, comes the exterior 
 casing, which, as has been already stated, may be either 
 of iron, brick, or masonry. 
 
 Fig. 6. Cupola blast furnace, 
 Barrow-in-Furnesa. 
 
168 METALLURGY OF IRON. 
 
 A small annular space, filled either with loose sand o? 
 small fragments of broken slag, is usually interposed 
 between each successive lining, in order to allow for any 
 alterations of form produced by the expansion of the 
 inner one. In the outer casing a number of square 
 holes are often provided for the escape of moisture; 
 these are more especially used in furnaces which only 
 remain in blast for a certain period of the year, as is 
 the case in Sweden, but in those that work continuously, 
 they are often omitted. 
 
 The lower portion of the furnace, including the 
 hearth and boshes, is built after the completion of the 
 stack. The foundation of the hearth varies with the 
 nature of the ground, and may sometimes require to be 
 commenced, in concrete and rubble work, at a consider- 
 able depth below the surface ; the hearth bottom consists 
 of a thick layer of fire-brick, or sandstone, in blocks of 
 as large a size as can be obtained, or in some cases both 
 materials are used. The bricks for this purpose are 
 laid in the form of an inverted flat arch, in order that 
 they may not be forced up in the event of the molten 
 metal finding its way through the joints. When a bed 
 of masonry is used below the hearth bottom, it is 
 generally built with a system of channels or flues inter- 
 secting at right angles, through which air circulates, 
 and prevents the access of moisture from the ground 
 to the hearth. The arrangement of these flues is 
 shown in Fig. 4. 
 
 The sides of the hearth and boshes, up to their junc- 
 tion with the stack, require to be made of refractory 
 material, and also of considerable thickness, having to 
 withstand a very high degree of heat, in addition to 
 the common action of the molten slags. When the 
 rectangular hearth was used, it was customary to build 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 169 
 
 these parts of sandstone similar to that employed for 
 the hearth bottom, but for the circular form brick is 
 generally adopted, and is in almost all cases to be pre- 
 ferred. 
 
 In Sweden and Germany the hearth and boshes are 
 often formed of a mixture of finely-crushed quartz or 
 ground fire-brick, and fire-clay, applied in a plastic 
 state, and rammed tight between the casing walls and 
 a wooden core or mould of the proper shape of the 
 cavity required, which is afterwards removed. This 
 kind of hearth, which is represented in the Swedish 
 furnace, Figs. 4, 5, is found to answer well in practice 
 for furnaces of small diameter, but requires to be very 
 carefully dried before being heated, in order to prevent 
 irregular shrinkage and cracking. 
 
 A short distance above the ground level the passages 
 for the introduction of the blast are perforated through 
 the wall of the hearth. These are known as the twyer 
 holes, and vary in number from two to six. On the front 
 or working side of the hearth, a square or flat-arched 
 opening extends from the hearth bottom to a little above 
 the level of the twyer holes. The vertical sides of this 
 opening are prolonged outwards for a short distance 
 into a rectangular cavity, known as the fore-hearth, 
 which is bounded in front by a wall of refractory 
 material, called the dam. The arch covering the opening 
 is called the tymp arch. 
 
 The exterior of the hearth, and the faces of the nume- 
 rous apertures pierced through it, are strengthened 
 with cast-iron plates and wrought-iron bracings. The 
 und*" 1 side of the arch is, in large furnaces, usually 
 prot-ccted by a cast-iron box or block, having a 
 wrought-iron serpentine pipe inside, through which a 
 current of water is kept flowing, in order to protect the 
 
170 METALLURGY OF IRON. 
 
 brickwork from destruction by the intense heat to 
 which it is exposed, and the corrosive action of the 
 molten slag which is constantly flowing through it. 
 
 The dam in front of the hearth is formed of fire- 
 brick, and is carried up to the twyer level. Externally 
 it is supported by a cast-iron plate, called the dam 
 plate. A semicircular furrow in the top edge, known 
 as the cinder notch, forms a passage for the slag, 
 which is now often moulded into large blocks by re- 
 ceiving it in a shallow square-bodied railway truck, 
 having movable sides of wrought iron. When the 
 truck or cinder tub is full, it is removed, and the block 
 of slag, weighing in some instances as much as 7 tons, 
 is, as soon as it has cooled sufficiently to become solidi- 
 fied, removed and thrown away. In charcoal and 
 other small furnaces, the front of the dam is generally 
 formed into a gently- sloping inclined plane or cinder 
 fall, where the slag as it runs out solidifies in a compa- 
 ratively thin layer, and may be broken up and re- 
 moved by hand. In Staffordshire, the slag is allowed 
 to collect in a shallow basin in the floor of the casting 
 house, called the roughing hole, where it consolidates 
 to an irregular disc-shaped lump, which is afterwards 
 lifted out by a crane, and sent off on a truck to the 
 slag bank or cinder tip. 
 
 The tap-hole for withdrawing the molten iron from 
 the hearth is a narrow vertical slit pierced through the 
 dam, and extending from the hearth bottom about 
 12 or 15 inches upwards. During the time that the 
 hearth is filling, it is stopped by a packing of sand 
 rammed in tight, which can be easily perforated by a 
 pointed bar, at the time of casting. The space between 
 the top of the dam and the tymp arch is also stopped 
 with sand or brick, a small passage being left for the 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 171 
 
 escape of slag. Sometimes the dam is raised above 
 the level of the twyer, so that a greater depth of 
 melted slag is retained in the furnace, and flows out 
 continuously, the top of the fore-hearth not being 
 stopped. 
 
 At either side of the tymp there are often fixed to 
 the hearth-casing a series of cast-iron plates with ver- 
 tical racks or notches, which form points of support or 
 fulcra for the heavy tools used in clearing the hearth 
 and other operations in the interior of the furnace ; 
 these are known in France as gendarmes. 
 
 Figs. 7 and 8, which are modified drawings of a 
 South Staffordshire furnace, represent the general 
 arrangement of the hearth of the blast furnace 
 mentioned in the preceding paragraph. Fig. 7 is 
 a front view of the exterior of the hearth, and Fig 8 
 a section on the line A B ; a is the dam in section, 
 b the cast-iron dam-plate, c the tap-hole, d the water 
 tymp in elevation in Fig. 7, and in section showing 
 the water passages in Fig. 8 ; e is the blast main, 
 and /a smaller pipe supplying water to the tymp and 
 twyers. 
 
 In Styria furnaces are built without fore-hearths or 
 tymp arches, the hearth being entirely closed, and the 
 slag and metal are allowed to accumulate, and are 
 tapped off together at short intervals. This construc- 
 tion is now becoming general in other countries, with 
 the addition of a passage for the slags, which is kept 
 constantly open. For the latter purpose Lurman's 
 slag twyer is used. This is a large water-cooled 
 bronze twyer of 7J inches bore in the place of the 
 tymp, into which is inserted another of 1J or 2 inches 
 aperture, through which the slag runs. 
 
 Details of the Top of the Furnace. The upper end 
 
172 
 
 METALLURGY OF IRON. 
 
 of the stack, or throat of the furnace, is surrounded by 
 a platform or charging plate sufficiently broad to give 
 room for working the barrows used in filling ore, fuel, 
 
 Fig. 7. Lower part of blast furnace, showing part of hearth and dam pi&ie. 
 
 and fluxes. In the older square- stacked furnaces, suffi- 
 cient space for this purpose could usually be found 
 
 Fig. 8. Lower part of blast furnace, section through hearth and dam. 
 
 between the ring wall and the external casing ; but in 
 the more taper cylindrical or conical forms of modern 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 178 
 
 times, additional surface is necessary. This is provided 
 by an overhanging gallery carried upon brackets, con- 
 structed entirely of cast and wrought iron. "When 
 two or more furnaces are placed adjacent to each other, 
 their galleries are united by bridges, which communi- 
 cate with the lifts for bringing up materials to the 
 furnace top. 
 
 When the gases are allowed to burn at the throat, 
 it is necessary to provide a chimney in order to carry 
 the flame clear of the charging place. For this 
 purpose a short cylinder of brickwork hooped with 
 wrought iron, or even of cast iron, is used, known as 
 the tunnel head. The charging holes are rectangular 
 apertures, varying in number with the diameter of the 
 throat, in the lower part of the tunnel head, through 
 which the charges of ore, fluxes, and fuel are intro- 
 duced. Except at the time of charging they are gene- 
 rally closed by wrought-iron shutters. 
 
 The arrangements of the head of the furnace when 
 the gases are collected are somewhat more complicated, 
 and will be described further on. 
 
 Lifts. In hilly countries, where the valleys are deep, 
 it often happens that blast furnaces can be placed below 
 the general level of the ground, supplying the ores 
 and fuel, so that all materials necessary for working 
 may be delivered at the furnace top without any special 
 appliances. In flat ground, on the other hand, such as 
 prevails in most of the iron districts of England, it 
 becomes necessary to resort to mechanical lifts for 
 raising the charges. The following are some of the 
 forms more generally employed. 
 
 Inclined Planes. These are mostly to be found in old 
 works, the more directly vertical lift being generally 
 preferred at the present day. They are usually made 
 
174 METALLURGY OF IRON. 
 
 with a double line of railway, or with a single line and 
 crossings for the return trucks, carried on trestle work. 
 The inclination is usually not more than 25 or 30 
 degrees. The most convenient form of truck is a 
 triangular frame, with two pairs of wheels of unequal 
 height, supporting a horizontal platform of sufficient size 
 to carry four or more of the iron wheelbarrows used in 
 charging, with their loads. The motive power is 
 usually a steam engine of from 10 to 20 horse power, 
 working a pair of winding drums. The load is drawn 
 either by wire ropes, or in Staffordshire by flat-linked 
 chains, such as are used in the same district for draw- 
 ing in collieries. 
 
 At the Barrow Iron Works, in Lancashire, two in- 
 clined planes are used for the supply of seven furnaces. 
 They are carried by bow and string girders of wrought 
 iron, and extend from the ground to the top of the 
 furnace, with only one intermediate support. The plat- 
 form waggon, carrying the barrows, is received into a 
 recess in the charging platform, and a similar one 
 below, so that the barrows with the loads may be 
 wheeled on and off. on their arrival at either end. The 
 motive power is a high-pressure steam engine placed 
 behind the furnaces, working a wire-rope drum. About 
 4,000 tons of materials are lifted weekly by each plane. 
 
 The most approved form of lift, where large quan- 
 tities of material have to be raised to a considerable 
 height, is a cage moving between vertical guides exactly 
 similar to those used in collieries. As the load is com- 
 paratively quickly raised, it is a useful precaution, 
 where steam power is used, to have no self-acting valve 
 gear, but to let the engine be entirely worked by hand, 
 in order to prevent the chance of accidents from over- 
 winding. 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 175 
 
 The water balance is an old and favourite form oi. 
 lift for small furnaces. It consists of two cages moving 
 vertically and guided, united by a rope or chain passing 
 over a guide pulley ; below the floor of each cage is 
 fixed a water-tight box, provided with a discharge 
 valve in the bottom. When the empty cage is at the 
 top of its stroke, water is allowed to flow into the box 
 until the weight is sufiicient to pull up the other cage 
 with a fresh load, the speed being regulated by a brake 
 on the guide pulley. As soon as the return cage reaches 
 the ground, the projecting stalk of the discharge valve 
 strikes against a catch, and is driven up, leaving a 
 passage for the water, which runs out, and the cage is 
 ready for another ascent when loaded. The chief merit 
 about this plan is its extreme simplicity and the large 
 useful effect got from the water, especially if a natural 
 fall can be used, otherwise it must be pumped up by 
 special machinery. The principal objection to it is the 
 difficulty of keeping the water boxes tight, the lift 
 houses being generally damp and sloppy from leak- 
 ages. 
 
 A more perfect kind of hydraulic lift is that con- 
 structed upon Sir William Armstrong's system, where 
 the lifting cage is connected to a water-pressure engine 
 by means of a chain passing over a system of compound 
 pulleys, so that when the engine makes a stroke of 6 
 or 8 feet the load is lifted through a height six or 
 eight times greater, according to the multiplying pur- 
 chase of the tackle. 
 
 Pneumatic lifts are now used to a considerable extent 
 in England, as the necessary power, compressed air, 
 may be readily obtained from the main blast engines 
 supplying the furnaces. The simplest form is a wrought- 
 iron cylinder, open at the bottom And closed at the top, 
 
1~0 METALLURGY OF IRON. 
 
 about 6 or 8 feet in diameter, and somewhat longer 
 than the height of the furnace, suspended in a tank 
 by counter-balance weights passing over pulleys in a 
 manner exactly similar to an ordinary gasometer. A 
 pipe for the admission of air at 3 or 4 Ibs. per square 
 inch above the atmospheric pressure, is introduced 
 through the tank. The waggon to be lifted is carried 
 on the top of the bell, and as the whole of the moving 
 parts of the apparatus are balanced, the amount of power 
 required is only that necessary to raise the additional 
 load. For the return stroke, the air within the bell is 
 allowed to escape by opening a valve communicating 
 with the atmosphere, the weight of the empty waggon 
 being sufficient to lower the bell in the tank. 
 
 In Gjers' pneumatic lift, which is much used in the 
 newer Cleveland furnaces, the motive power, instead of 
 being taken from the main blast engine, is furnished 
 by a pair of double-acting air-pumps, the lift being 
 effected by the pressure of the atmosphere acting against 
 a vacuum in a cylinder, while the empty waggons are 
 returned by compressing air under the piston. 
 
 The Jacob's ladder, or endless chain system of lift, 
 usually described in older works, is probably no longei 
 in use. 
 
 Blowing Machines. The use of cast-iron cylinder 
 blast engines has almost everywhere superseded the 
 ruder contrivances of wooden chests with square pis- 
 tons, bellows, &c. In Sweden, for small furnaces and 
 forges, the single-acting form of engine is much used, 
 being cheap and economical in working and main- 
 tenance. Usually three inverted vertical cylinders are 
 employed, of about 3J or 4 feet diameter and length 
 of stroke, carried on cast-iron or wooden standards, and 
 driven directly by a water-wheel. 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 177 
 
 The cylinder is provided with an air-tight piston, to 
 which a reciprocating motion is imparted by appropriate 
 mechanism. Two sets of valves are placed on the 
 cylinder cover : the longer series open inwards as the 
 piston recedes, giving a passage for the admission of 
 the external air, and at the change of stroke are closed 
 by the compressing force exerted by the piston on the 
 included air ; and the second series, or discharge valves, 
 which are in connection with the blast reservoir, open, 
 and allow the compressed air to pass out. In the 
 single-acting engine only one end of the cylinder is 
 covered and provided with valves ; while in the double- 
 acting form (represented in Fig. 9) both ends are 
 similarly arranged, so that one side of the piston is 
 drawing air through the intake valves, a, while the 
 
 other is compressing the 
 volume taken in at the pre- 
 ceding stroke, and driving it 
 over into the reservoir through 
 the discharge valves, b. 
 
 The valves employed are 
 generally oblong rectangular 
 plates, with their shorter sides 
 placed vertically one of the 
 long sides forming the hinge. 
 In order to combine rigidity 
 with lightness, it is usual to 
 make them of a combination 
 
 Fig. 9. Cylinder Mast engine. /> , -, . -, , . . , -i 
 
 oi thin sheet iron, with contact 
 surfaces of felt, leather, or india-rubber. The hinge 
 
 Imay be either of metal, accurately fitted, or merely a 
 flexible leather flap. The seats or boxes to which they 
 are affixed are usually rectangular tubes projecting from 
 the outer face of the cylinder cover. In order that fcha 
 
 i3 
 
178 METALLURGY OF IRON. 
 
 valves may close by their own weight when relieved 
 from the pressure of the air, it is usual ^o fix the beat- 
 ing face of the seat in an inclined position, or counter- 
 balance weights or springs of steel or india-rubber may 
 be used for the same purpose. 
 
 As the motion of the valves is similar to that of 
 the pendulum, the time required for opening and 
 shutting them is dependent on their vertical length, 
 so that the piston cannot be driven beyond a certain 
 speed, unless mechanical means, capable of being 
 increased pari passu with the speed of the engine, 
 be employed. This has been attempted in the so- 
 called slide-blowing engines, where the flap valves 
 are replaced by a slide similar to that used in 
 steam engines, which travels at the same rate as the 
 piston, and places the apertures at either end alter- 
 nately in communication with the external air and the 
 blast reservoir. The system of construction has been 
 adopted at different times both in England and on the 
 Continent. The best-known form is Slate's engine, 
 where the slide is annular, and placed outside of the 
 vertical blast cylinder, receiving motion by means of a 
 pair of parallel rods connected with the rotary shaft of 
 a steam engine below. The form of the slide is the 
 solid of revolution produced by the rotation of an 
 ordinary -/"V shaped slide valve about a vertical axis, 
 formed by the centre line of the steam and blast pistons. 
 In Thomas and Laurent's arrangement the cylinder is 
 horizontal ; the air passages are of a rectangular form, 
 and are, together with the slide, placed laterally in the 
 same manner as the steam ports and slide valve in an 
 ordinary horizontal steam engine. 
 
 In Fossey's engine, which was exhibited in the 
 Belgian department of the Exhibition of 1862, the 
 
OF THE BLAST FURNACE AND ITS Jf^ESSORIES. 179 
 
 slide valves are replaced by discs with, radial perfora- 
 tions, which, are put in slow rotary motion by gearing 
 from the fly-wheel shaft. A jacket is cast round the 
 cylinder, with an interspace forming the passage from 
 the cylinder to the reservoir. The apertures in the 
 disc are sixteen in number, a corresponding series 
 being formed in the cylinder ends, which are alter- 
 nately opened and closed by the rotation of the disc in 
 conformity with the motion of the piston. In the for- 
 mer position the external air is admitted, while in the 
 latter the volume enclosed is driven over into the 
 jacket and reservoir. In practice the use of the slide 
 blast engine has not been found to be advantageous, 
 owing to the large amount of mechanical effect con- 
 sumed by the friction of the slide against the rubbing 
 face of the cylinder, which would be great in itself, on 
 account of the high speed at which they require to be 
 driven, but is materially increased, owing to the dusty 
 state of the atmosphere almost unavoidable in iron- 
 works. 
 
 In the ordinary form of engine with flap or clack 
 valves it is necessary to provide as large an area of 
 air ways as can be got out of the surface of the cylinder 
 cover. The intake passages should be made, if possible, 
 equal to one-half, and the outlet about one-eighth, of 
 the area of the piston. As it is impossible in large 
 engines to use single valves of these dimensions, on 
 account of their weight, and consequent liability to give 
 rise to injurious shocks in working, it is customary, 
 therefore, to employ a number of small valves, whose 
 united areas make up the required amount of surface. 
 
 The question of the relative advantages of horizontal 
 and vertical blast cylinders has been discussed at con- 
 siderable length by engineers, both in this country 
 
180 METALLURGY OF IRON. 
 
 and on the Continent. As in many other matters 
 depending upon practical experience, there is much 
 to be said on either side. For engines of small 
 dimensions the horizontal form is cheaper, and may be 
 worked with the least amount of clearance from the 
 vertical position of the cylinder covers, which may be 
 pierced through like a gridiron, giving a bearing for 
 the valves, without any overhanging parts or valve 
 boxes. The required foundations may also be less 
 massive than in the vertical form, owing to the longer 
 bearing of the framing, when a horizontal direct- 
 acting steam engine is the motor ; this, of course, 
 necessitates the comparatively larger surface for the 
 engine-house. On the other hand, the difficulty of 
 lubrication is increased, as the powdered graphite, which 
 is generally used for this purpose, instead of being 
 uniformly distributed round the pistons, is apt to fall 
 to the bottom of the cylinder, while the upper side 
 works dry, and the cylinder wall is worn irregularly, 
 and becomes ovalised. The difficulty of keeping the 
 weight of the piston off the bottom, and producing the 
 same kind of unequal wear, is also urged against the 
 use of large horizontal cylinders ; but this objection, 
 which has also been applied in the case of horizontal 
 steam engines, does not appear to be productive of any 
 practical disadvantage in the larger modern engines 
 used for screw propulsion, whose diameters are quite 
 equal to those of the average of blast cylinders. 
 
 In regard to vertical beam engines the chief disad- 
 vantages are their great length and expensive character 
 of construction, and the extra amount of clearance, equal 
 to the volume of the valve boxes, rendered necessary by 
 the horizontal position of the cylinder covers ; on the 
 other, they have the great advantage of stability, and 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 181 
 
 may be made of any dimensions ; thus, in South Wales, 
 engines are in use with blast cylinders up to 12 feet in 
 diameter. In engines giving small volumes of blast at 
 very high pressure, such as are used in Bessemer's 
 process, the valves require to be made extremely 
 light: the construction employed in such cases is a 
 plain ring or plate of india-rubber covering a perfo- 
 rated plate, which opens and shuts by its own elasticity 
 when exposed to, or relieved from, pressure. 
 
 In Coulthard's blast engines the air passages are 
 circular holes in the cylinder, similar to those used by 
 Bessemer, but the valves are light wooden balls covered 
 with india-rubber, which are arranged on inclined and 
 grooved seats, sloping in a direction contrary to that of 
 the current of air, so that when the pressure is suffi- 
 cient to drive the balls up the incline the air way is 
 opened ; but as soon as it is relieved, they roll down 
 again, and stop the passage. 
 
 The combination of the blast and steam cylinders, 
 when steam power is used, is effected in various ways. 
 The large vertical engines of modern date in this 
 country are beam engines, the main bearing being 
 supported either on the engine-house wall or on an 
 entablature carried by cast-iron columns. The piston- 
 rods are attached by the ordinary parallel motion. On 
 the steam side, the beam is often continued beyond the 
 point of articulation of the piston-rod, and turned up- 
 ward into a short crane neck, to the end of which the 
 connecting-rod working the fly-wheel is attached. 
 This arrangement permits the use of a long light con- 
 necting-rod, without unduly increasing the surface 
 occupied by the engine. 
 
 In Belgium, direct-acting engines with vertical 
 cylinders are much used, the blast cylinder being placed 
 
METALLURGY OF IROW. 
 
 uppermost. In an engine of this class built at Seraing, 
 Evans's beam, with an oscillating centre, is adopted, in 
 order to keep the working parts within a comparatively 
 small space, the length of the base of the engine- 
 house being little more than the radius of the fly-wheel, 
 or about 25 feet. The height, owing to the two 
 cylinders being placed one above another, is consider- 
 able, being not less than 40 feet. The steam cylinder 
 is 41 J inches, and the blast cylinder 66 inches ; the 
 length of stroke 88 inches. When working with steam 
 of 30 Ibs. pressure, and blowing air at 4J Ibs. above 
 the atmosphere in sufficient quantity for a large furnace 
 burning coke, the work done is equal to between 80 and 
 100 horse power. In the newer kind of engines built 
 at the same works, the vertical direct-acting form is 
 preserved, but the piston-rods are guided by sliding 
 blocks instead of the older and more complicated 
 arrangement of Evans. 
 
 In Austria a class of small direct-acting engines of 
 the same character is used for charcoal furnaces, having 
 the steam cylinder placed uppermost, which, together 
 with the framing for the guides, is bolted on to the 
 top flange of the blast cylinder. They are usually of 
 small dimensions, averaging from 25 to 30 horse power, 
 and delivers from 2,300 to 2,500 cubic feet of air per 
 minute. 
 
 In Siegen, and other parts of Rhenish Prussia, hori- 
 zontal blast engines are preferred. The commonest 
 pattern has both cylinders placed in the same line ; the 
 rod which carries the two pistons goes through both 
 covers of the blast cylinder, and is guided on either side. 
 Usually two engines are coupled together upon the 
 same fly-wheel, but the construction is such that they 
 may be disconnected if only the power of one engine is 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 183 
 
 wanted. For charcoal furnaces from 30 to 40 horse 
 power is considered sufficient, but with the larger ones, 
 working on coke, from 80 to 100 horse power is found 
 to be necessary, as in other districts. 
 
 The same kind of horizontal engine is generally 
 adopted in new works in Sweden and Lapland, having 
 only a single charcoal furnace. 
 
 The working limits of blast pressure vary with the 
 nature of the fuel employed, and the burden of the 
 furnace, &c. Thus, in some of the small charcoal 
 furnaces of Northern Europe, it does not exceed half 
 or three-quarters of an inch of mercury above that of 
 the atmosphere ; while in American anthracite fur- 
 naces as much as 15 inches, or 7J Ibs., is used. In 
 England from 2J to 3 Ibs. is used with cold blast and 
 tender fuel, but 3|, 4, or 5 Ibs. is common with hard 
 coke. In Bessemer's process of steel-making, by 
 forcing air through a column of molten pig iron, a 
 pressure of from 15 to 20 Ibs. per square inch is 
 used. 
 
 The largest blast engines hitherto constructed are 
 those at Dowlais and Ebbw Yale, in South Wales ; the 
 former, which was erected by the late Mr. Truran, has 
 a cylinder 144 inches in diameter, with the same 
 length of stroke ; the area of the admission valves is 56 
 square feet, that of the discharge valves 16 square feet, 
 the former being equal to half the surface of the piston. 
 The steam cylinder is 55 inches in diameter, with a 
 piston making a stroke of 13 feet, the motion being 
 transmitted by an unequal-armed beam. Owing to the 
 large area of the air ways a very high speed, as many 
 as 20 strokes per minute, can be obtained. The volume 
 of blast delivered is about 51,000 cubic feet, at a 
 pressure of 3 j Ibs., sufficient for the supply of six large 
 
184 METALLURGY OF IRON. 
 
 furnaces and four refineries. The main blast pipe is 
 5 feet in diameter. The Ebbw Yale engine has a 
 blowing cylinder of the same size, but the steam cylinder 
 is 72 inches in diameter. 
 
 The practice of blowing several furnaces by one 
 engine of large size, though mechanically advantageous, 
 is attended with considerable risk, as the safety of the 
 furnaces may be endangered in the event of a break- 
 down, unless there be a reserve of blowing power. It 
 is therefore preferable to divide the work between two 
 or more engines, according to the number of furnaces 
 in blast. Where there is only a single furnace, as is 
 usually the case in char coal- smelting, two small engines 
 coupled together, but capable of being worked indepen- 
 dently of each other, may be used, for the same reason. 
 
 Blast Regulators. The air or blast issues from the 
 blowing cylinder in an irregular stream, owing to the 
 variation in pressure at different points of the stroke, 
 the supply being intermitted during the period of 
 actual compression after the closing of the intake, and 
 before the opening of the discharge valves. In order, 
 therefore, to produce a steady current in the furnace, 
 it is necessary to use some means of equalising the 
 pressure. This may be done either by receiving the 
 blast into a reservoir whose volume is several times 
 that of the blowing cylinder, or by delivering it into a 
 second cylinder containing a loaded piston, which rises 
 when the supply of blast is greater than the amount 
 required bv the furnaces ; but when the quantity 
 diminishes the piston falls, and exerts a compressing 
 force, until the equilibrium is restored by increasing 
 the speed of the engine. The same effect may be 
 produced, with less loss from friction, by the use of a 
 loaded bell, or gasometer, floating in a water tank- 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 185 
 
 The volume of these regulators may be from one and 
 a half to twice that of the blast cylinder. 
 
 Fixed reservoirs are usually made of wrought iron ; 
 formerly a spherical, or balloon-shaped form was com- 
 monly adopted, but they are now more generally made 
 cylindrical, with flat ends like high-pressure steam 
 boilers. The thickness of the plates, of course, depends 
 upon the pressure and dimensions employed, as well as 
 the form adopted : from one- twelfth to one- eighth of 
 an inch may be taken as sizes commonly used. The 
 volume of the regulator may be from twenty-five to fifty 
 times as great as the amount of blast in cubi'c feet delivered 
 by the engine per second, when it is placed near the 
 furnace, but this may be considerably diminished when 
 a long blast main is used. Indeed, it often happens 
 that sufficient uniformity can be got in the latter case, 
 especially when several engines are used, by blowing 
 into the main direct, without the use of a special 
 regulator. 
 
 Regulators in masonry or brickwork are usually 
 lined with cement in order to protect the air from 
 taking up moisture. A regulator of this character, 
 consisting of a chamber cut out in the solid rock, was 
 applied at Devon Iron Works, in Scotland, as early as 
 1792. 
 
 Blast Heating Apparatus. The use of heated air in 
 the blast furnace, which was first introduced by Neil- 
 son in 1828, has been found to be attended with a 
 great economy of fuel, and at the same time the work- 
 ing power of the furnace is increased. It is therefore 
 employed at the present day in iron-making districts 
 all over the world, almost to the exclusion of cold 
 blast, the latter being retained only for certain special 
 makes which command an extra price, and may there- 
 
186 METALLURGY OF IRON. 
 
 fore be produced without the strict regard, to econo- 
 mical considerations which is necessary when working 
 on an article of lower repute. 
 
 The amount to which the temperature of the blast 
 may be raised with advantage does not appear to have 
 any practical limit, every fresh increase being attended 
 with further saving of fuel ; thus, in the first instance, 
 100 were found to be an advantage over air at the 
 ordinary temperature ; then came temperatures of 200 
 400, up to the melting-point of zinc ; and now it is 
 actually used at a visible red heat, or about 700. 
 Thus it was found that a saving was produced of 
 5 cwt. of coke per ton of iron made by using air 
 heated to about 650, instead of the lower tempera- 
 ture of 350 or 400, previously employed. The dif- 
 ficulty of keeping the apparatus tight, and the rapid 
 destruction, of metal pipes when heated to redness in 
 air, render a special construction necessary for the 
 production of such extremely hot blast economically. 
 
 The greater number of blast-heating apparatus in 
 use at the present time, and known as hot blast ovens or 
 stoves, consist essentially of a series of parallel, or 
 spiral tubes, arranged in a chamber of fire-brick, and 
 heated externally by a fire. The opposite ends of 
 these tubes are connected with two mains intersecting 
 them at right angles. One of these supplies cold air, 
 while the other, or hot blast main, removes the heated 
 air. 
 
 In the older forms of stove, such as that originally 
 adopted at Calder, in Lanarkshire, the fireplace is an 
 oblong rectangle in plan. The two mains, which are 
 placed parallel to the longer sides, are of a circular 
 section, and cast with a number of circular sockets for 
 the heating pipes. These are arched, horse-shoe. 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 187 
 
 siphon, or inverted U pipes, also circular in section, 
 placed with, the arched portion upright, and luted into 
 
 the sockets on the mains. 
 The fire-grate runs along 
 the whole length of the 
 bottom, and the flame, 
 after playing on the un- 
 der sides of the tubes, 
 passes between and around 
 them, by means of appro- 
 priate flues, into the chim- 
 ney, while the cold air, en- 
 tering by the main on one 
 side, flows continuously 
 through the arched pipes, 
 where it becomes heated, 
 and passes off to the fur- 
 nace by the opposite main. 
 This arrangement is shown, in Fig. 10, in section 
 across the shorter side of the stove : a is the cold blast 
 main ; b the hot blast main ; c the arched heating 
 pipe set in sockets on the two mains ; and d the fire- 
 grate. 
 
 To obviate the defects of this apparatus, many 
 special modifications have been introduced. Thus, 
 in order to get a greater amount of heating surface, 
 the horse- shoe pipes are now usually made of flattened 
 elliptical, or rectangular, instead of circular section. 
 A smaller radius of curvature for the arch has been 
 obtained by the use of inverted V pipes, and more 
 uniformity in heating, by the introduction of stops 
 at intervals in the entry main, so that the air is 
 made to pass alternately backwards and forwards 
 several times across the arch, instead of moving 
 
 Fig. 10. Hot blast stove. Dowlais. 
 (Truran). 
 
188 METALLURGY OF IRON. 
 
 only in one direction, as was the case in the original 
 form. 
 
 Whatever system of construction is used, the air 
 should pass through the apparatus in the reverse direc- 
 tion to the flame, entering cold, at the end farthest 
 from the hottest point of the fire. 
 
 Arch-headed pipes are very easily broken by irre- 
 gular expansion at the crowns, if a certain freedom 
 of motion is not allowed to the ends ; this is equally 
 provided against by placing one of the mains loose on 
 its bed, supporting it by spherical bearings, so that it 
 may travel outwards to a slight extent as the pipes 
 become heated. 
 
 Round and oval ovens have been introduced to 
 obtain a more uniform heat than can be got by the 
 old rectangular form. These terms refer to the 
 shape of the base, or fireplace. The mains are re- 
 placed by a cast-iron box of a square or trapeziform 
 section, divided by a central partition, one division cor- 
 responding to the cold, and the other to the hot blast 
 main. The vertical pipes, instead of being arched at 
 the top, are united by a short horizontal one, the limbs 
 being close together. This variety is much used in 
 Staffordshire and Lancashire. 
 
 A modification somewhat similar to the last, known 
 as the pistol pipe, is used in Scotland, Cleveland, and 
 other districts in this country, and is also rather in 
 favour in France and Germany. The two vertical 
 pipes or limbs are replaced by a single one, divided bv 
 an internal partition reaching nearly to the top. It is 
 closed at the upper end, and is either straight, slightly 
 bulbed, or bent over into a half arch. One of the 
 divisions is connected with the intake, and the other 
 with the exit, so that the cold air rises on one side, and 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 189 
 
 passes through the bulbed chamber at the top, down 
 
 the other, heated to 
 the furnace. When the 
 curved head is used, it is 
 usual to place two series 
 of pipes in opposite di- 
 rections with the heads, 
 meeting so as to form an 
 arch for mutual support ; 
 but, of course, the ques- 
 tion of unequal expansion 
 does not arise, as each 
 half of the arch is inde- 
 pendent of the other. 
 The term pistol pipe is 
 derived from the resem- 
 blance of the curved 
 head to a pistol stock, 
 the straight portion corresponding to the barrel. This 
 construction is represented in Fig. 11, the left-hand 
 'pipe being shown in section, and the right-hand one in 
 elevation. 
 
 All the preceding forms of stoves are characterised 
 by the use of air ways presenting continual changes of 
 form ; thus the blast passes from the main through the 
 heating pipes alternately backwards and forwards. In 
 what are known as spiral-pipe ovens, the heating is 
 effected in tubes of uniform section, arranged similarly 
 to the worm of a still. Among these may be mentioned 
 the apparatus in use at Ebbw Vale, a horizontal 
 coil of cast-iron pipes exposed to a fire running the 
 whole length of the axis. The pipes are formed in 
 segments corresponding to one-half of a complete turn 
 of the screw, and are united by ordinary socket joints. 
 
 Fig. 11. Pistol-pipe hot blast stove. 
 Oberhausen. 
 
190 METALLURGY OF IRON. 
 
 The union of the pipes and mains in stoves is always 
 effected in the same manner, the latter being cast with 
 sockets for receiving the ends or feet of the pipes, 
 which are often made slightly conical, spigot fashion. 
 The joint is made air-tight by rust cement. 
 
 Stoves with straight or serpentine horizontal pipes 
 are much in vogue in Germany, and are known 
 after the name of the works at "Wasseralfingen, in 
 Wurtemberg, where they were first introduced. In 
 the original construction a number of straight pipes 
 of circular bore, placed horizontally, extend from 
 side to side of the walls of the fire chamber in a 
 manner exactly similar to the tubes of a locomotive, 
 and are united into a continuous serpentine coil by 
 external arched bends not exposed to the fire. In 
 this way the difficulty arising from the tendency of 
 the pipes to break at the bends, owing to irregular 
 expansion when heated, is avoided. The newer forma 
 differ chiefly from the foregoing in the section of 
 the pipes, which are now usually elliptical instead of 
 circular. The position of the longer axis may be 
 either horizontal or vertical ; the latter, being the most 
 advantageous arrangement, is usually adopted. 
 
 Fig. 12 is a section of a stove of this pattern at Neu- 
 stadt, in Hanover. The coil consists of four pipes united 
 by semicircular bends, four similar series being united by 
 other bends placed horizontally, so that the whole appa- 
 ratus contains sixteen pipes. The cold air enters at c, 
 and passing downwards, issues in a heated state at d. The 
 fuel employed is the waste gas from the blast furnace, 
 which is supplied through the wrought-iron main, a, 
 and jet-pipe, b. The latter is provided with a central 
 tube for the admission of the air necessary for burning 
 tke gas. 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 191 
 
 Thomas and Laurent's stove, used in severai of the 
 newer French furnaces, consists of three vertical tubers 
 of large diameter, united by external horse-shoe pieces 
 placed externally, as in the Wasseralfingen apparatus. 
 
 Fig. 12. Hot blast stove. Wasseralfingen pattern. 
 
 In order to obtain a larger heating surface, the inner 
 side of the tube is studded with projecting radiating 
 ribs about 3 inches high, the remaining interior space 
 being filled with a cylindrical core of cast iron or 
 fire-brick. These ribs are not continuous in the same 
 place throughout the entire height of the tube, but are 
 interrupted at different levels, the series above and 
 below being arranged so as to break joint with the 
 central one. By this means the air is forced to travel 
 in a somewhat deviating course through the passages 
 enclosed between the core and the ribs. A very con- 
 siderable heating effect is claimed for this arrange- 
 ment, which is similar to that of the stoves known as 
 " gill calorifiers," used for warming large rooms ; but 
 
192 METALLURGY OF IRON. 
 
 it is attended, owing to the irregular section of the air 
 ways, with a notable loss of pressure from friction. 
 
 In considering hot blast stoves, we have hitherto 
 assumed that the heating of the air is to be effected by 
 means of fuel burnt on a grate below the pipes. This 
 is still done to a considerable extent, but the substitu- 
 tion of the waste gases of the furnace is now almost 
 equally common, especially in furnaces using fuel 
 brought from a distance. For this purpose it is neces- 
 sary to bring a branch pipe to the stove from the main 
 gas conduit, which terminates either in a series of jets, 
 or more commonly in a rectangular mouth-piece, a 
 special aperture of a similar character, for the admission 
 of air, being placed immediately above or below. 
 
 It is generally advisable to have a grate with a 
 small fire, which insures ignition of the gases ; with- 
 out this, in case of the flame becoming extinguished, 
 air would be liable to get back into the gas main, 
 where it would most probably produce an explosion. 
 
 Cowper's stove, for heating air to very high tempera- 
 tures, is constructed on the so-called " regenerative " 
 principle of Siemens. It consists, as shown in section, 
 Fig. 13, of a cylindrical chamber, with a low-domed 
 roof of fire-brick work, cased with wrought iron ; the 
 discharging passage for the hot blast, made of similar 
 materials, projects on one side, opposite to which is the 
 stack for producing the necessary draught. 
 
 In the interior of the chamber a vertical shaft, A, 
 whose diameter is about one-third of the whole space 
 between the walls, extends from the floor nearly to the 
 roof, and communicates at the bottom with the passages, 
 B, by which the inflammable gases and air are ad- 
 mitted, and by a horizontal flue, c, with the hot blast 
 exit passage. The annular space between the central 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 193 
 
 shaft and the walls of the chamber contains two parallel 
 ring flues ; these serve alternately for the admission of 
 cold blast, and the escape of spent flame to the chimney. 
 Above these flues, which occupy about a quarter of 
 the total height of the chamber, the whole of the re- 
 
 Fig. IS.-^-Cowper's hot blast stove. 
 
 maining space, up to the springing of the dome, is 
 filled with fire-bricks loosely stacked, so that a large 
 number of small rectangular openings are left between 
 them, forming the channels for the blast and gases to 
 circulate. During the time of heating, the hot and 
 cold blast valves, E and F, are shut, and the gas and 
 air valves, G and H, below the central shaft, opened. 
 The ignited gas then rises up the shaft, and passes 
 downwards through the bricks and lower ring flues into 
 the chimney, the draught being regulated by a special 
 damper. 
 
 The heat evolved by the burning gases is transferred 
 to the bricks, the temperature of the layers being in- 
 
194 -METALLURGY OP IRON. 
 
 creased progressively from above downwards, until, in 
 about two hours' time, the whole contents of the 
 chamber are brought to a uniform strong red heat : 
 the air, gas, and chimney valves are then closed, and 
 the cold blast is admitted by the valve, F, and passes 
 through the chamber in the reverse direction to the 
 heating current, upward through the bricks, abstract- 
 ing their heat, and down the central shaft through the 
 hot blast valve, E, to the furnace. The current of cold 
 air is continued until the bricks, with the exception of 
 a few of the upper layers, are no longer red-hot ; the 
 blast is then stopped, and the heating is recommenced 
 by admitting gas and air as before. It is of course 
 necessary to have two stoves in order to keep up the 
 blast continuously, one being heated while the other is 
 cooling, and vice versa. By this system of stove the 
 gaseous fuel is very perfectly economised, the tempera- 
 ture of the current in chimney being not much above 
 that of boiling water, 100 C to 120, while the blast is 
 made visibly red-hot, and capable of melting antimony 
 with ease, corresponding to a temperature of 700 to 
 800. In this stove all the parts brought into contact 
 with the heated air are made of refractory brickwork, 
 with the exception of the hot blast valve, which is of 
 cast iron, with double walls, and cooled with water like 
 an ordinary hot blast twyer. 
 
 Fig. 14, taken from Tomlinson, shows the course of 
 the air and gas in a pair of these stoves when at work. 
 The right-hand one is being heated, while the other is 
 giving up its acquired heat to the blast. Fig. 15 shows 
 the manner in which the bricks are stacked in tho 
 regenerators. 
 
 A simple form of the stove last mentioned has been 
 recently introduced by Whitwell. In it the cellular 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 195 
 
 piles of bricks are replaced by plain walls ; the formar 
 
 Fig. 14. Cowper's hot.'blast stove plan. 
 
 C. Chimney. H.B. V. Hot blast valve. 
 
 C.V. Chimney valve. A V. Air valve. 
 
 G. V. Gas valve. CiB. V, Cold blast valve. 
 S. Shut. 0. Open. 
 
 method of construction being objectionable when blast- 
 furnace gas is used for heating, as the spaces between 
 
 r~ir ii 1 in lag 
 
 J _KL EL*. M . 
 
 L JL X 
 
 Fig. 15. Cowper's hot blast stove. Details of arrangement of bricka, 
 
 the bricks are liable to become choked by the deposit 
 of flue dust. The oven or heating chamber is enclosed 
 by four upright walls, and divided by internal, upright, 
 parallel partitions into several narrow compartments. 
 
 K2 
 
196 
 
 METAL1AJKGY OF IRON. 
 
 Fig. 15* represents "Whitwell's stove, as applied to a 
 blast furnace at Consett. It is one of four, each mea- 
 
 Fig. 15* 
 
 suring 22 feet in diameter, by 25 feet nigh, and con- 
 taining 9,000 square feet of heating surface, or 36,000 
 feet in all. 
 
 The stove is circular in form. The gas enters at B, 
 sufficient space being allowed at the hot end, L, for the 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 197 
 
 ignition of gas by air admitted through the cellular 
 passages 1. The flame is conducted through the stovo 
 by conduits, o K, 9 inches broad, the average width of 
 the passages in a transverse line across the stove being 
 about 15 feet, thus giving a total length of flue of 
 240 feet, with a section of 11 square feet, care being 
 taken so to place the arches, o, above and below the 
 alternate walls, that the gas may be equally distributed. 
 Other air passages are placed at 2, 3, and 4, in order to 
 ensure perfect combustion of the gas. 
 
 Of the 240 feet of travel, or 9,000 square feet of 
 surface, about two-thirds, 180 feet and 6,000 square 
 feet respectively, are raised to a bright red heat, as 
 seen through the eye-pieces, 1 1, perforating the casing 
 and shell, by which the state of the interior can be 
 readily observed. In the remaining space of one- third 
 the temperature shades down gradually, until the pro- 
 ducts of combustion pass off to the chimney, c, where 
 their temperature is reduced to about 300. When 
 the stove has been heated to this point, the gas- inlet- 
 valve, B, and chimney-valve, c, are closed, as well as 
 all the air- valves, 1 , 2, 3, 4, and the hot and cold blast 
 valves, D and A, are opened. The cold blast now enters 
 at T> } and passing over the walls in reverse order to the 
 gas, commencing at the coldest end, is gradually heated 
 until it attains the temperature of the hottest surface, 
 when it passes through tubes lined with 9-inch brick- 
 work, and enters the blast-furnace at a visible red heat, 
 about 650. Of the four stoves, Nos. 1 and 3 and 2 
 and 4 are worked in pairs, the blast being on the 
 former while the latter are heating. The hot-blast 
 main is 3 feet in external diameter, giving a clear air- 
 way of 18 inches within the 9-inch fire-brick lining. 
 
193 METALLURGY OF IRON. 
 
 The blast is allowed to pass for two hours, by which 
 time only one- third of the whole surface remains at a 
 red heat, below which it is not allowed to cool, in order 
 to ensure regularity in the working of the furnace. 
 
 At the hot end, L, the first walls are constructed half 
 of ganister, and half of fire-brick. The transverse walls, 
 which are 7 inches thick, are built in lumps, 12 inches 
 by 7 inches by 3 inches. All the brickwork is carefully 
 laid, the joints being perfectly flushed up with fire-clay. 
 The weight of brickwork in each stove is 298 tons. 
 The hot blast and gas- valves are of cast iron, with a 
 hollow space between the sides, through which, as well 
 as through the seatings, a current of water circulates, 
 care being taken to prevent the blast from impinging 
 directly upon the cooled surfaces. When it is desired 
 to clean the stove, the gas having been shut off and the 
 chimney-valve slightly opened, in order to carry the 
 heat downwards, the first top cleaning-door, F, at the 
 hot end is taken off, and the movable plug in the crown 
 of the arch, N, lifted. Scrapers with f-inch tubular 
 handles, screwed together to attain the right length, 
 are introduced, and the walls on either side are scraped 
 down, the dust falling to the bottom. The compart- 
 ment being thus cleaned, the door is replaced and luted 
 with fire-clay, and the same process is repeated with 
 the doors in rotation while the walls are red hot. The 
 side doors, E, at the bottom are then opened, and the 
 dust detached from the walls is raked out. The opera- 
 tion, which takes about nine hours, is repeated every 
 two or three months, according to the amount of dust 
 brought over by the waste gases. 
 
 In the construction of the stove, a space of 1 inch is 
 left between the brickwork and the wrought- iron 
 
OF THE BLAST FL'RNACE AND ITS ACCESSORIES. 199 
 
 casing, which is filled with dry clay or granulated slag, 
 so as to allow for any expansion of the brickwork. A 
 similar allowance is made at the top. 
 
 By the use of these stoves a very considerable saving 
 has been effected in the consumption of coke per ton of 
 pig iron made, on account of the very high temperature 
 of blast obtained. The furnace to which they have 
 been applied makes 400 tons weekly, with a consump- 
 tion of 17J cwt. of coke per ton. The charge contains 
 two-thirds calcined Cleveland stone and one-third red 
 hematite, yielding about 48 per cent, of iron. The 
 blast is heated to 730, and temperature of the gases 
 at the top is 250. An adjoining furnace of the same 
 size, and working on the same ores, with a blast heated 
 to 450, consumes 22 J- cwt. of coke to the ton, and 
 gives off the waste gases at 470. 
 
 The construction of firebrick stoves has of late been 
 simplified, while the dimensions have been very largely 
 increased. The Cowper stoves, at Ormesby, are 52 feet 
 high and 23 feet diameter. The regenerator space is 
 14,500 cubic feet. Each cubic foot contains 0'49 of 
 its volume of bricks, with 4-9 square feet of surface, 
 giving a total of 71,000 feet of heating surface. Two 
 stoves of this size serve a furnace making 500 tons of 
 pig iron per week, with coke consumption of 21 cwt. 
 per ton. The blast, 14,500 cubic feet per minute, is 
 heated to 780 degrees. The stove may be kept on 
 blast for three hours without lowering the temperature 
 more than 50 degrees. The combustion chamber, 
 instead of being central, as in Fig. 13, is placed at one 
 side ; the gas is admitted at the bottom, and split up 
 into three parts, so as to insure complete combustion 
 by perfect admixture with air. It is essential, however, 
 
200 METALLURGY OF IRON, 
 
 that the heat of the gaseous current entering the 
 regenerators shall not be sufficient to glaze the bricks ; 
 as their heat- absorbing capacity is much diminished 
 when glazed. It is, therefore, preferable to use a large 
 surface of thin brickwork at a moderate, rather than a 
 thick mass, at a high heat. The bricks now used 
 measure 2 by 5 by 12 inches, and are laid in open 
 courses, so as to give passages 4 inches square, which 
 extend through the entire height of the stove, and 
 can be swept with a brush. Another method of clean- 
 ing that is found to be very efficacious, is to open the 
 manhole door when the blast is shut off the furnace at 
 tapping-time, and allowing it to blow through, when a 
 rush of air escapes, carrying with it much of the 
 deposited dust. In order, however, to keep out the 
 finely divided particles of ore which destroy the 
 bricks by slagging their surfaces, the gas from the 
 tunnel head is passed through a tube of enlarged section 
 forming a dust-catcher, and then through a washer, 
 where it meets a water spray formed by the waste 
 twyer water falling upon iron splash-plates. After 
 passing the washer the calorific value of the gas by 
 being freed from dust is considerably enhanced. 
 
 Whitwell's stoves are now made much higher than 
 formerly. At Millom, in Cumberland, it was found 
 that by raising the stove from 28 feet to 40 feet the 
 temperature of the escaping gases was reduced from 
 360 to 495 after the gas had been on for three hours. 
 This, by increasing the heating surface, gives greater 
 regularity in working the furnace. The sizes now 
 used vary from 15 to 22 feet in diameter and 40 to 70 
 feet in height, the largest size made in America 
 having 30,900 feet of heating surface. The number 
 of changes in the direction of the flame has also been 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 201 
 
 considerably reduced by diminishing the number of 
 intermediate walls from eleven (Fig. 15) to five. 
 The gases enter the large combustion chamber, where 
 they are mixed with hot air drawn by a new arrange- 
 ment through the bottom brickwork. The flame rises to 
 the top, then descends three smaller chambers simul- 
 taneously, where more warm air is admitted. It again 
 descends through two or three chambers at once, and 
 finally descends the last three or four chambers, having 
 been mixed with air at each change of direction, after 
 which it escapes to the chimney cooled to about 350. 
 There are six doors at the top for introducing scrapers 
 in cleaning the walls of the chambers, and an equal 
 number at the bottom for removing the dust that 
 has fallen from the walls. The scraping and cleaning 
 occupy only six hours every three or four months. 
 
 The amount of heating surface in hot blast stoves 
 with cast-iron pipes is usually about one square foot per 
 cubic foot of blast passing through per minute when 
 fired with coal. With gaseous fuel it is advisable to 
 make them from 10 to 20 per cent, larger. 
 
 Pressure Gauges. For low-pressure blast, such as is 
 used in small charcoal furnaces, or for determining the 
 tension of the waste gases, a water gauge is generally 
 used, but for the more highly compressed air used in 
 furnaces on mineral fuel, mercury gauges are necessary. 
 When the blast is at a very high temperature, it is 
 necessary to make the observations as quickly as 
 possible, or to cool the air down by passing it through 
 a tube placed in a current of water, before allowing it 
 to come in contact with the mercury. By multiplying 
 the indications of the mercurial gauge in inches Ly 
 13-59, the corresponding height measured in water is 
 
 K 3 
 
202 METALLURGY OF IRON. 
 
 obtained, and conversely, inches of water gauge may 
 be reduced to mercurial inches by dividing by the same 
 constants. When, as is usually the case, the height of 
 the water gauge is expressed in feet and inches, it may 
 be reduced to the corresponding pressure in inches 
 and lines of mercury by multiplying by 0-882. The 
 amount of blast passing through a twyer is found by 
 multiplying the velocity of the current passing per 
 minute or second, as deduced from the pressure, by its 
 sectional area. The result must, of course, be corrected 
 for temperature, atmospheric pressure, and moisture, 
 and for the contraction of the jet at the point of 
 efflux. The latter correction varies in amount with 
 the form of the nozzle, and is somewhat greater for 
 cylindrical than conical pipes, and also increases with 
 the pressure employed. As a general rule, the diminution 
 of volume from this cause may be taken at about 8 
 per cent., and the real amount found by multiplying 
 the theoretical quantity by 0'92. 
 
 The determination o/ the amount of blast carried 
 into the furnace, from the observations given above, 
 may be approximately found by the following formula, 
 given by Weisbach, as a simplification of the more 
 exact one deduced by him from Poisson's law, checked 
 by actual experiment : 
 
 /T i-ois 
 
 Q=1179]T>V/1 * 1 ^ 00036727 
 
 where Q = the number of cubic feet discharged per 
 second, reduced to the temperature of 10 Centigrade, 
 and 30 inches barometrical pressure, F = area of 
 twyer, h = observed height of pressure gauge in 
 inches of mercury, b = observed height of barometer. 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 203 
 
 The second part gives the correction for the heat of the 
 blast, when r = its temperature in Centigrade degrees. 
 In the first part of the above formula, F is taken in 
 square feet, by dividing by 144, or, putting F = 1 square 
 inch, we obtain the following simple expression : 
 
 (2) 
 
 which gives the volume of blast per second per square 
 inch of the sectional area of the twyer. The following 
 table gives the value of Q for different values of the 
 
 fraction in formula (2) : 
 
 h 
 S 
 
 a 
 
 h 
 
 I 
 
 Q 
 
 o-oi 
 
 0-82 
 
 0-30 
 
 4-49 
 
 02 
 
 1-16 
 
 35 
 
 4-85 
 
 05 
 
 1-83 
 
 40 
 
 5-19 
 
 10 
 
 2-59 
 
 45 
 
 5-50 
 
 15 
 
 3-18 
 
 50 
 
 5-80 
 
 20 
 
 3-67 
 
 55 
 
 6-08 
 
 25 
 
 4-10 
 
 60 
 
 6-35 
 
 These quantities require to be corrected for temperature 
 when hot blast is used by the second part of formula (1). 
 
 The quantity of air passing into a furnace may also 
 b? decided from the composition of the waste gases 
 when the furnace works with a closed top, and the 
 whole of the volatile products are collected. 
 
 Determination of the Temperature of the Blast. Mer- 
 curial thermometers cannot be used in determining 
 temperatures much above 200 or 250 with accuracy, 
 owing to the irregular expansion of the mercury when 
 near its boiling-point. For measuring the high tern- 
 
204 METALLURGY OF IRON. 
 
 peratures prevailing in blast-furnace operations, me- 
 tallic pyrometers of various kinds are employed; 
 depending either on the expansion of a single metal, 
 or a combination of two, such as iron and copper or 
 platinum. These, although convenient, are liable to 
 give inaccurate results after a time, from the metals 
 becoming permanently expanded when repeatedly 
 heated. 
 
 In practice the temperature of the blast is generally 
 determined by its power of fusing metals. This is done 
 by exposing a thin rod of the metal to the current in 
 the twyer, a hole being made for the purpose in the 
 elbow of the branch pipe connecting the twyer with 
 the blast main. 
 
 The following are the reputed melting-points of the 
 metals available for determining the temperatures of 
 hot blast : 
 
 Degrees. 
 
 Tin . f . <- f v 245 
 Bismuth . . , . .250 
 Lead 330 
 
 Zinc . . . t .410 
 
 Antimony . ,J..,_. .512 
 
 In experiments on the temperature of the interior of 
 the furnace, such as those made by Tunner in Styria, 
 and Einman and others in Sweden, alloys of gold and 
 silver, and silver and platinum, are used, the increase 
 of the melting-point being assumed as directly propor- 
 tional to the increase in the amount of the more 
 refractory metal. This method was also used by 
 Plattner in determining the temperature of fusion of 
 slags. 
 
 The following table contains the melting-points 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 2Q5 
 
 of various alloys used for the above purposes by 
 
 Tunner : 
 
 Degrees. 
 9 Lead -f 1 Silver melts at 400 
 
 
 8 
 
 2 
 
 470 
 
 
 7 
 
 3 
 
 540 
 
 
 6 ,, 
 
 4 
 
 610 
 
 
 5 ,, 
 
 ft 
 
 680 
 
 
 4 ,, 
 
 6 
 
 750 
 
 
 3 
 
 7 
 
 815 
 
 
 2 
 
 8 
 
 ,, 885 
 
 
 1 
 
 9 
 
 955 
 
 
 0'6,, 
 
 9- 
 
 4 980 
 
 
 
 
 Degrees. 
 
 9-5 
 
 Silver + 
 
 0'5 
 
 Gold melts at 1,030 
 
 7 
 
 ,, 
 
 3 
 
 1,050 
 
 4-5 
 
 ,, 
 
 5-5 
 
 1,070 
 
 2 
 
 ,, 
 
 8 
 
 1,090 
 
 
 
 
 Fine Gold ,, 1,100 
 
 9 
 
 Silver -f- 
 
 1 
 
 Platinum 1,175 
 
 8-5 
 
 ,, 
 
 1-5 
 
 1,250 
 
 8 
 
 
 
 2 
 
 1,325 
 
 7-5 
 
 n 
 
 2-5 
 
 1,400 
 
 7 
 
 
 3 
 
 1,475 
 
 6-5 
 
 55 
 
 3-5 
 
 1,550 
 
 5 
 
 5 
 
 5 
 
 1,625 
 
 Pouillet's pyrometric method, which consists in ob- 
 serving the increase of temperature produced in a 
 weighed quantity of water by plunging into it a mass 
 of metal, whose weight and specific heat are known, 
 heated to the temperature to be measured, has also 
 been applied to the construction of pyrometers for 
 blase furnaces; a ball of copper is used for medium, 
 and platinum for higher temperatures. From the 
 increase in the sensible heat of the water, the loss 
 
206 METALLURGY OF IRON. 
 
 experienced by the metal may be found by the follow- 
 ing formula : 
 
 t' = V where 
 
 W 8 
 
 w = weight of water, t = its increase of temperature, 
 w - weight of metal ball, s = its specific heat. To 
 this result must be added the observed temperature of 
 the water in order to get at that of the furnace. 
 
 Siemens' pyrometer, which is used to a considerable 
 extent for measuring hot blast temperatures, is of this 
 kind, and is thus described by the inventor : 
 
 "It consists of a portable vessel, formed of three 
 concentric cylinders of thin copper plate, the space 
 between the inner and middle one being filled with 
 cowhair, and that between the middle and outer one 
 with air, so as to prevent as perfectly as possible the 
 loss of heat from the interior. A delicate mercurial 
 thermometer is fixed in the interior of the vessel, being 
 protected by a perforated shield, and furnished with 
 a movable sliding- scale, showing pyrometer degrees, 
 each of which is equal to 50 of the ordinary thermo- 
 metric scale. For obtaining the temperature, balls of 
 copper or platinum are used, which are so adjusted that 
 fifty of them would be equal in thermal capacity to an 
 imperial pint of water. Each ball is perforated by a 
 hole, through which a rod is passed in exposing the 
 same to the action of the heat to be measured. Imme- 
 diately before using the instrument, an imperial pint of 
 water is poured into it, and the slide is so moved that 
 the zero point of its scale corresponds with the top of 
 the mercury in the thermometer. The ball, after hav- 
 ing been exposed to the heat for two or three minutes, 
 is plunged into the water. The mercury will then 
 l>e observed to rise, and the absolute measure of the 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 207 
 
 temperature is obtained by adding the reading on the 
 pyrometer scale opposite the new level of the mercury 
 to the original temperature of the water before the 
 ball was introduced. With a little practice very satis- 
 factory results may be obtained with this instrument ; 
 but its application is limited to the heat at which the 
 metal ball is deteriorated; nor can it be used for 
 measuring the temperature of inaccessible places." 
 
 Another pyrometer, recently invented by Mr. Sie- 
 mens, is based upon the property possessed by pure 
 metals of offering an increased resistance to the passage 
 of an electric current in proportion as their tempera- 
 ture increases. A platinum wire of known resistance 
 is wound upon a helical groove on the surface of a 
 cylinder of fire-clay, and enclosed within a cylindrical 
 casing of platinum if the temperature to be measured 
 exceeds the welding point of iron, or copper 
 for lower temperatures. The two ends of the coil 
 are brought endways, and are attached within the 
 tube to thicker wires of copper, insulated for a short 
 distance by a coating of pipeclay, and further on, when 
 beyond the influence of the heated space, by india rubber 
 or gutta percha. These wires communicate with the 
 measuring instrument, which may be placed at any 
 convenient distance. The latter is a specially con- 
 structed galvanometrical arrangement, and is go gra- 
 duated that a reading in degrees on a divided scale 
 may be at once obtained. These do not give an abso- 
 lute measure of temperature, but the final result is 
 taken out from a table calculated for each instrument. 
 The pyrometer coil may be either fixed permanently, if 
 it is desired to have a means of continuously determin- 
 ing the temperature of a particular place, or it may be 
 
208 METALLURGY OF IRON. 
 
 introduced into the furnace through a door or other 
 opening for a minute or two, which is sufficient time 
 to obtain a reading. The latter is the only method 
 available for very high temperatures ; for by continuous 
 exposure the protecting case, even when of platinum, 
 would be ultimately destroyed. The electrical resist- 
 ance of platinum wire is increased fourfold by a rise of 
 temperature from to 1650. 
 
 Position of Hot Blast Stoves. It is in all cases de- 
 sirable to place the stoves as near to the furnace as is 
 consistent with the other requirements of the works, in 
 order that the blast may lose as little of its acquired 
 heat as possible, by not having to travel a long dis- 
 tance through pipes exposed to the air. In some in- 
 stances, especially in small charcoal furnaces, where 
 the stoves are heated by waste gases, they are placed 
 on a level with the furnace top, the gases being led in 
 by a short flue in order to economise their sensible 
 heat, as well as the much greater quantity derived from 
 their subsequent combustion. The hot blast main is then 
 carried down vertically to the twyers. This practice is 
 tolerably common in Swedish and German charcoal fur- 
 naces, and appears to be very general in the United 
 States, where the blast- engine boilers are often carried 
 on the top of high- vaulted structures in the same 
 manner. Much greater regularity of draught, and 
 especially freedom from choking by dust, can be ob- 
 tained when the stoves are placed at the ground 
 level, and the gases are brought down by a suitable 
 conduit. 
 
 Arrangement of the Twyers. The blast coming from 
 the stoves passes through a ring main, which, in the 
 old square-cased furnaces, is carried through the cir- 
 cular passage traversing the stack pillars ; but in the 
 
OF THE BLAST FURNACE AND IPS ACCESSORIES. 209 
 
 newer forms is generally attached to the columns, 
 surrounding the hearth at a certain distance above the 
 ground. A vertical branch pipe, or goose neck, is led 
 ofi' opposite to each twyer hole, and at the proper level 
 is turned over at right angles into a horizontal arm, 
 to which the blast nozzle, or blowpipe, is attached. 
 
 A throttle, or slide valve, for stopping or regulating 
 the blast, is attached to each branch, as well as to the 
 main near the stove. 
 
 In cold blast furnaces the air is led through a conical 
 copper nozzle, attached to a branch pipe by a flexible 
 leather tube ; but with hot blast it is requisite to make 
 all the fittings of metal, and the necessary means of 
 adjustment are provided by interposing a sliding or tele- 
 scopic tube and a ball-and-socket joint between the end 
 of the branch pipe and the twyer. By the former the 
 twyer is set to the proper length, while the latter allows 
 the direction of the entering blast to be varied, so that 
 it be made level, plunging or rising at pleasure. 
 
 When hot blast is used, it is necessary to protect the 
 walls of the hearth from the intense heat generated by 
 the energetic combustion going on immediately in 
 front of the twj^ers. This is done by the use of water 
 <wyers, which are hollow, conical, or tapering D- shaped 
 tubes, with double walls, which are kept cool by a 
 current of water circulating through the interspace. 
 
 Fig. 16 represents a hot blast twyer as applied to a 
 charcoal furnace at Bhonitz, in Hungary, a is the 
 water twyer, formed of cast and wrought iron, with 
 double walls, which are cooled by a current of water 
 circulating through the intermediate space, b is the 
 blowpipe, which is of sheet iron, and bears against a 
 divergent conical orifice placed within the water twyer. 
 The latter arrangement is not usual, the end of the 
 
210 METALLURGY OF IRON. 
 
 blowpipe being generally inserted loose in the twyer, 
 and the intermediate space stopped with clay. The 
 axis of the jet may be made horizontal, or to incline 
 upwards or downwards by means of the ball-and- 
 socket adjustment at c. The end of the twyer is ad- 
 
 Fig. 16. Hot blast water twyer. Ehonitz, Hungary. 
 
 vanced or withdrawn by the telescopic joint and setting 
 screw at d. The flanged elbow-pipe fits on to the 
 vertical branch pipe of the hot blast main. At c the 
 elbow is perforated by a small hole, having a movable 
 shutter, containing a plate of glass or mica, which 
 gives a view of the interior of the hearth, or rather of 
 the bright spot, or eye, immediately in front of the 
 twyer. Through this aperture the fusible metals used 
 in trying the temperature of the blast are introduced. 
 
 Water twyers are made either entirely of cast or 
 wrought iron alone, of a combination of both, or of 
 copper or bronze. The water space is .usually rectan- 
 gular in section, but sometimes a spiral tube of wrought 
 iron is used, either alone or set in a casing of cast iron. 
 An advantage is claimed for bronze twyers of not 
 being readily destroyed by "ironing," that is, of being 
 melted by the imperfectly- fused masses of metallic iron 
 which sometimes adhere to the end of the twyer when 
 the furnace is not in good working order, and the 
 reduced iron is imperfectly carburised. The removal 
 of the adherent masses may be effected by raising the 
 dam, and allowing the cinder to rise above the level of 
 the twyers. Leaky water twyers are productive of 
 great waste of fuel, owing to the large amount of heat 
 
OF THE BLAST FUK^ACE AND ITS ACCESSORIES. 211 
 
 absorbed in the decomposition of the steam produced in 
 the hearth. The temperature in the region of fusion 
 is consequently lowered, with the production of white 
 iron of a low degree of carburisation. When the leak 
 is considerable the consequences may become more 
 serious, as the water, if it gets into the lower part of the 
 hearth, is likely to produce an explosion. 
 
 The number and arrangement of twyers vary very 
 considerably. The smaller charcoal furnaces have 
 often only two, placed on opposite sides of the hearth. 
 Three is a more usual number, one being placed 
 at the back ; i.e., opposite to the tymp, and the 
 others at the sides of the hearth. "When a larger 
 number is used, they are generally placed at equal 
 intervals all round the hearth. This method is usually 
 adopted in cupola furnaces ; but in South Wales, 
 where there are many large furnaces with only three 
 twyer arches, they are sometimes arranged in series ; 
 thus, two will be put through each of the side open- 
 ings, and the same number at the back, or three at the 
 sides, and one or two at the back, &c. This is done to 
 avoid the use of twyers of an excessive diameter, and, 
 by multiplying the points of contact with the fuel, to 
 make the combustion more uniform over the entire 
 area of the hearth. Sometimes a special twyer is added 
 on the tymp side, for the purpose of removing irregu- 
 larities caused by local cooling, and is only used in 
 case of the hearth becoming obstructed. 
 
 Methods of Collecting Waste Gases. In small char- 
 coal furnaces, working with an open throat, the gases 
 are often taken off by wrought-iron pipes perforating 
 the wall of the furnace about 10 or 12 feet below the 
 top. This plan is commonly used in Sweden for sup- 
 plying gases to mine kilns, hot blast stoves, &c., but 
 
212 METALLURGY OF IRON. 
 
 can only be practised on a small scale. The supply ie 
 apt to be somewhat irregular, from the stoppage of the 
 holes by the descending charge. A more perfect 
 method for the same purpose, is that of contracting the 
 throat by the insertion of a cast or wrought-iron cylin- 
 der of somewhat smaller diameter than the ring wall, 
 so that an annular space at the top is kept clear from 
 the materials of the charge, and forms a collecting flue 
 for the gases. In order to present the charges from 
 blocking up the lower part, it is usual to increase the 
 diameter of the shaft by the amount required to form 
 the flue, and the tube restores the furnace to its original 
 section. The application of this arrangement is shown 
 in the charcoal furnace, Fig. 4. 
 
 When it is desired to collect the whole of the gases 
 given off at the top of the furnace, it is necessary to 
 
 work with a closed throat. 
 The most generally used, 
 and, at the same time, one 
 of the simplest contriv- 
 ances for this purpose is 
 that known as the cup and 
 cone, Fig. 17, It consist; 
 
 Fig. 17.-Furnace top, with cup-and-cone f an inverted Conical CUSt- 
 
 char cr - iron funnel fixed to the 
 
 top of the furnace, whose lower aperture is of about 
 one-half of the diameter of the throat. An upright 
 cast-iron cone is placed in the furnace below the 
 cup ; it is suspended by a chain attached to its apex, 
 so that it may be raised or lowered at pleasure ; in the 
 former position it bears against the bottom of the 
 cup, and forms an air-tight stopper, preventing the 
 escape of any gas from the top of the furnace, which 
 then finds its way out by proper passages through the 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 
 
 wall of the furnace in the space above the charges 
 enclosed by the cup ; but when lowered it allows the 
 charges in the cup to be dropped into the furnace, and 
 at the same time acts as a distributer. Only the 
 small amount of gas that is lost during the time of 
 charging is allowed to escape, and as this operation is 
 very quickly performed, the current through the mains 
 is kept up with great regularity. The cone is suspended 
 by an arch-headed lever, carrying a counterbalance at 
 the end of the opposite arm. The raising or lowering 
 is effected by a pinion, moved by a hand- wheel gearing 
 into a segmental rack attached to the counterbalance 
 weight. The gas passes through a lateral flue into a 
 square wrought-iron main pipe, or conduit, which dis- 
 tributes it to the various pipes feeding the boiler fires 
 and hot blast stoves. A modification of the cup and cone 
 is in use in Cleveland, where the cone is replaced by 
 an external cylindrical stopper, which is lifted during 
 the charging time, and lowered when the throat is 
 stopped, the object being to allow the charges to occupy 
 the space which is necessarily kept empty for working 
 the cone on the old system. It was found, however, 
 that the working of the furnace was injured from the 
 want of a proper distributer for the charges, on account 
 of the absence of the cone : when this was supplied by 
 suspending a conical ring by three chains to the bottom 
 of the plug, regularity in charging was restored. 
 
 In the above methods, the gas is collected chiefly 
 from the sides of the furnace, a practice which, as will 
 be shown further on, is not in all cases to be recom- 
 mended. The alternative plan is to collect from the 
 centre ; this is usually done by inserting an iron tube 
 a short distance down the centre of the furnace, the lower 
 end being supported on ribs of brickwork, while tho 
 
214 METALLURGY OF IRON. 
 
 upper part is turned over in the form of a siphon, as, 
 for example, in the furnace, Fig. 6, at p. 142. The annular 
 opening between the tube and the ring wall forms the 
 space for charging, an arrangement exactly the reverse 
 of that noticed at p. 179. Only a part of the gases are 
 collected by this method. The draught is in some cases 
 aided by an exhausting fan. Coingt's apparatus, in 
 use in France, is a combination of the central tube with 
 the cup and cone. 
 
 Langen's apparatus, Fig 18, differs from those 
 
 hitherto considered, 
 in being placed above 
 the furnace, which 
 may therefore be 
 kept filled to the 
 throat in the same 
 manner as one with- 
 out any means of 
 collecting gases. The 
 
 Fig. 18.-Furnace top, with Langen's charger. cnar gi n g portion IS a 
 
 conical ring, whose smallest diameter is equal to that of 
 the throat, into which the charges are filled in the usual 
 way. The gas tube is also slightly conical, diminishing 
 upwards ; the lower end, which is about 5 feet above 
 the top of the column of materials in the shaft, is turned 
 over into a gutter or water trough. The gases rising 
 from the furnace are collected in a bell- shaped tube, 
 whose lower end rests in the conical cup at the top oi 
 the furnace, while the upper part is turned over into 
 a lip, w r hich dips into the water trough on the gas tube, 
 forming a perfectly air-tight stopper. At the time of 
 charging, the bell, which is suspended by chains 
 to a lever, is lifted, the upper end sliding on the out- 
 side of the gas tube, which forms a kind of telescopic 
 
v)F THE BLAST FURNACE AND ITS ACCESSORIES. 215 
 
 joint. The charges in the cup then fall into the .fur- 
 nace. In order to keep the water joint tight, it is 
 necessary to make good the waste caused by evapora- 
 tion from time to time, owing to the high temperature 
 of the gases. To prevent the chance of an explosion, 
 a safety-valve is placed on the top of the gas tube at 
 #, and another on the lateral tube at b. 
 
 Even in furnaces where the gases are not collected, 
 the use of a conical charger is attended with consider- 
 able advantage. Where the diameter of the throat is 
 large, it is customary to fix charging plates inclining 
 inwards, immediately within the charging holes, which 
 dist-ribute the charges in a similar manner. 
 
 In the charcoal furnaces of Lake Superior and Styria, 
 a charging barrow is used, which is constructed exactly 
 in the same manner as the cup and cone. The body of 
 the barrow is an inverted eight-sided pyramidal cup, 
 the bottom being an upright cone, which, when dropped 
 by a lever attached to its summit, leaves an annular 
 space for the materials to pass out into the furnace, at 
 the same time they are directed towards the circum- 
 ference of the throat, in sliding over the surface of the 
 cone. At Ehonitz, in Hungary, charging barrows are 
 used having sliding cylindrical sides in addition to the 
 dropping conical bottom, so that the charging takes 
 place in a ring towards the sides of the furnace as well 
 as at the centre. 
 
 Biittgenbach's system of furnace construction origi- 
 nally adopted at Neuss, on the Ehine, has been followed 
 to some extent in France and Germany. In this 
 neither red-brick nor sheet-iron casing is used, the 
 stack wall being formed of single rings of moulded fire- 
 bricks, with a few wrought-iron hoops. This i.g carried 
 upon cast-iron columns, or brick-piers, the hearth 
 being entirely independent and accessible on all sides. 
 
216 
 
 METALLURGY OP 1ROX. 
 
 The charging platform is carried by the gas down- 
 comer, which, instead of being a single large tube, is 
 diverted into several smaller ones, which together form 
 a kind of scaffolding to support the top of the furnace, 
 part of it being carried by the stack wall, which is free 
 
 JD 
 
 Fig. ISA. Buttgenbach's Blast Furnace. 
 
 to expand and contract under changes of temperature, 
 as it is relieved from the downward pressure of the 
 heavy structure at the top. This arrangement is 
 shown in Fig. 18A, which represents the section of a 
 furnace at Schwechat, near Yienna. The stack consists 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 217 
 
 of a single thickness of fire-brick hooped with iron 
 rings, carried upon arches uniting piers of red brick- 
 work 23 feet high, upon a base 40 feet square. The 
 upper end of the stack is cased with sheet iron for a 
 height of about 12 feet, and the hoops are united 
 together by flat bars of iron, forming a casing which, 
 while it allows the bricks to be freely exposed to the 
 air, is sufficiently strong to bear a part of the weight 
 of the top of the furnace, the remaining support being 
 given by the gas down-comers. The hearth has seven 
 courses of water blocks built into it between the twyers 
 and the junction with the stack. These are flat cast- 
 iron boxes covered with sheet iron and open behind. 
 Water is introduced by a pipe into the uppermost series, 
 and flows downwards through the lower ones ; the 
 cooling action tends to preserve the brickwork of the 
 boshes from corrosion, especially when the ore contains 
 much manganese. The gas brought down from the 
 furnace top is received in a ring-shaped tube, partly 
 filled with water and open at the side. The water is 
 raised in the opening by the pressure of the gas, and 
 forms an air-tight joint. The furnace is 61} feet 
 high, 18 \ feet diameter in the boshes, and 7J feet in the 
 hearth ; the capacity is 9990 cubic feet, and the daily 
 make 45 to 50 tons of Bessemer iron from the spathic 
 ore of Styria. 
 
 Form of the Interior of the Blast Furnace. In laying 
 out new works at the present time it is usual to build 
 the furnaces of a more or less skittle or tub-shaped 
 section, all sharply contrasted slopes being avoided, the 
 diameter increasing continuously from the throat to 
 the boshes, and then being contracted in a similar 
 manner down to the hearth-bottom, without having a 
 cylindrical hearth. The form of the body of such a 
 
318 METALLURGY OF 
 
 furnace is well represented by a common soda-water 
 bottle, supposing the neck and the pointed bottom to 
 be removed. In Scotland the same kind of section is 
 used, with the addition of a broad cylindrical hearth. 
 In Cleveland slightly-curved stacks, with conical 
 boshes and cylindrical hearths, are the rule. In South 
 Wales the latter conditions are often reversed, the 
 lower part, up to the top of the boshes, being made 
 conical, while the stack, which is for a certain distance 
 cylindrical, is terminated by a strongly- curved dome. 
 In all cases of the above, however, the hearths are of 
 considerable breadth. 
 
 In French, Belgian, and German furnaces curved 
 sections are less common than in this country. A more 
 especial characteristic is, however, the small diameter 
 of hearth generally adopted, the sides being brought in 
 from the boshes in a strongly-curved convex sweep. 
 This type, which is usually combined with an extremely 
 massive construction of hearth, is very similar in form 
 to an inverted claret bottle, having the bottom and the 
 greater part of the neck removed ; the body, which 
 increases from the bottom upwards with a slight taper, 
 representing the stack, the shoulder the sweep of the 
 boshes, and the narrow neck the hearth. Swedish 
 charcoal furnaces are generally of considerable height 
 when compared with their diameter ; the hearth and 
 boshes form part of the same cone, usually very acute. 
 The stack is either wholly or in part cylindrical. In 
 Styria the charcoal furnaces used for smelting spathic 
 ores resemble those of Sweden by their considerable 
 height, as compared with the breadth and the steep 
 slope of the conical parts, but are specially distinguished 
 by their extremely narrow throats, which in some in- 
 stances do not exceed 2-] feet. 
 
 The height and other dimensions of blast furnaces 
 
OP THE BLAST FUKNACE AND ITS ACCESSORIES. 219 
 
 vary very considerably in different localities with the 
 nature of the ores and fuel. ~No special rules can be 
 laid down as to the form best suited for a particular 
 class of ore, experience having shown that the require- 
 ments of each class are to be met by special arrange- 
 ments. The most useful guide in the construction of 
 new furnaces is furnished by the condition of thos 
 that have been blown out after working upon the 
 same kind of ore. It was by comparisons of this kind 
 that the modern barrel-shaped furnace was elaborated 
 by Gibbons, in South Staffordshire, from the older 
 conical form, the section of the newer furnace being 
 modified wherever the action of the fire was found to 
 be strongest : thus square hearths were burnt out to a 
 circular form, and the sharp angle at the joining 
 of the hearth and boshes was also removed. It was 
 therefore apparent that, by altering these parts in con- 
 formity with the indications, a double advantage was 
 attained, a certain amount of materials being saved, 
 while the furnace was sooner brought to its best work- 
 ing condition than was the case when it had first to be 
 cut into shape by the heat. 
 
 If we consider the nature of the work done in the 
 blast furnace with reference to the amount of iron pro- 
 duced in a given time, it will be evident that an increase 
 of such production can only be obtained from the same 
 ores by passing a larger number of charges through in 
 the same time ; this, however, depends upon the facili - 
 ties possessed for withdrawing them by fusion at the 
 bottom ; for, however great the cubic contents may be, 
 it is "clear that new materials can only be supplied in 
 proportion to the speed with which those charged before 
 them are removed. 
 
 The power of fusion is, however, to be measured by 
 the space offered for combustion of fuel by the blast, 
 
220 METALLURGY OF IRON. 
 
 and as in the best condition of work, this space should 
 be confined as much as possible to the plane of the 
 twyers, it follows that increase of space for more active 
 combustion is to be got mainly by augmenting the width 
 of the hearth. The amount of such an increase is to be 
 determined by the power of the blast, which must be of 
 sufficient tension to penetrate to the centre of the 
 hearth. 
 
 Greater height may be given to a furnace, either to 
 increase its capacity, or to intercept more completely 
 the enormous quantity of heat carried upward by the 
 gaseous products of combustion. Strictly speaking, 
 there should be no combustion of fuel, except in the 
 region of fusion, and the space immediately adjoining, 
 where the carbonic acid produced at the twyers is con- 
 verted into carbonic oxide. The latter gas, and the 
 nitrogen of the air consumed, are charged with the 
 reduction of the oxides of iron in the ore to the metallic 
 state, and the progressive heating of the materials in 
 the upper region of the furnace. The greater the dis- 
 tance, therefore, of the upper end of the column of 
 materials from the level of most active combustion, the 
 more perfectly will the heat be abstracted from the 
 gases ; therefore, we might expect that the greatest 
 economy of fuel would be found in the tallest furnaces, 
 and this is practically the case, as exemplified in the 
 newer furnaces in Cleveland, which have been succes- 
 sively increased from a height of 50 or 60 feet to 70 
 feet and upwards, in one instance attaining as much as 
 96 feet, with an increased saving of fuel in each case. 
 Of course only the sensible heat is abstracted from the 
 gases, an amount that is quite independent of the 
 further and much larger quantity that may be got by 
 burning them in air. 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 221 
 
 The conditions limiting the height of the furnace 
 Ere mainly due to the character of the ores and fuel, as 
 regards their power of resisting crushing when exposed 
 to the pressure of a tall column of materials, and the 
 initial velocity of the blast. The favourable results 
 given above, as obtained in Cleveland, are due to the 
 extremely hard character of the coke employed, which, 
 according to Bell, is capable of resisting a crushing 
 strain of 5 cwt. per square inch. Yery tall furnaces, 
 therefore, can scarcely be used with tender fuel, such as 
 soft charcoal, or coal, and pulverulent ores. Much of 
 the anthracite of South Wales is in the same condition, 
 as it decrepitates, and is apt to choke up the furnace, if 
 not removed by an extra-powerful blast. The furnaces, 
 therefore, worked with this fuel, though of large 
 diameter, and provided with a great number of twyers, 
 are usually of small height. 
 
 The time occupied in the descent of the materials 
 from the throat to the hearth is chiefly dependent upon 
 the capacity of the furnace. It is of the greatest im- 
 portance that this should be so regulated as to insure 
 an early commencement of the reduction of the ore to 
 the metallic state at a low temperature, otherwise, in 
 the event of protoxide of iron and silica coming in con- 
 tact with each other in a more highly-heated atmo- 
 sphere, a silicate is formed, which is easily fusible, 
 but difficultly reducible, and, running down into the 
 hearth, forms what is known as a scouring or black 
 cinder, at the same time giving rise to white iron. 
 The harder a furnace is driven, therefore, the greater 
 is the tendency to deterioration in the quantity of the 
 metal produced, owing to the quicker descent of the 
 charges ; and it will, therefore, be apparent that when an 
 increased make is desired, larger furnaces should be used, 
 
222 
 
 METALLURGY OF IRON. 
 
 The difficulty of insuring uniformity of temperature 
 in circular hearths of large character has led to 
 the proposal of a more elongated form, such as an 
 ellipse or oblong rectangle ; the latter being adopted 
 in Eachette's furnace, which was introduced in Eussia 
 a few years back, and has been tried experimentally in 
 other parts of Europe. It is represented in plan and 
 section in Figs. 19 and 20. 
 
 The oblong hearth is combined with a shaft, increas- 
 ing regularly in diameter upwards, the section at the 
 
 Eachette's blast furnace. 
 Fig. 19. Vertical section. Fig. 20. Plan at twyer level. 
 
 throat being from two and a half to three and a half 
 times as large as that measured at the level of the 
 twyers. The object of this arrangement, which gives 
 a furnace similar in form to a calcining kiln, is to pro- 
 duce a more prolonged contact between the gases and 
 the materials of the charge, by reducing the velocity of 
 the upward current. 
 
 The use of drying flues is another new feature in 
 Bachette's furnace ; these are a series of ramifying 
 rectangular passages, traversing the outer casing of the 
 stack at different levels, which are in connection with a 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 223 
 
 similar chamber placed below the hearth. Before 
 olowing in, a fire, placed in the chamber, warms up 
 *he whole of the masonry uniformly, and more quickly 
 Shan can be done on the old system ; afterwards the 
 jlues may be used for the reverse purpose of cooling the 
 masonry by the circulation of cold air. The twyers, 
 from twelve to sixteen in number, are arranged in two 
 rows, breaking joint with each other, on the opposite 
 long sides of the hearth ; a dam and tapping place are 
 provided on each of the short sides, so that the removal 
 of slag and iron may be effected from either end. 
 
 In order to obtain greater regularity in the distribu- 
 tion of the blast, the large number of twyers may be 
 replaced by a single mouth-piece, with a long, narrow, 
 rectangular aperture, which delivers the air in a thin 
 stream uniformly along the entire length of the hearth. 
 This system of twyer, together with the elliptical form 
 of hearth, has been adopted in the construction of 
 cupolas for smelting slags in the Lake Superior copper 
 works. In the original furnaces of this class in th* 
 Ural, the breadth of the hearth at the twyers is 3 feet, 
 at the throat 7 feet, height 30 feet, cubic capacity 1,950" 
 feet, and the daily production, when working on rich 
 magnetic ore (67 per cent.), with charcoal and cole? 
 blast, about 30 tons of grey pig iron. 
 
 The mode of charging has an important infiuenc6 
 upon the working of blast furnaces : this becomes evi- 
 dent when we consider that, in order to obtain regularity' 
 of action, the descending materials ought to be heated 
 uniformly by the upward current of hot gases. This, 
 however, is by no means the case, owing to the essential 
 differences in the character of the two motions, the 
 gases following the sides of the furnace close to the 
 wall, the flow at the centre being almost imperceptible. 
 
%'l I METALLURGY OF IRON. 
 
 Thus, in an open-topped furnace, a wooden pole may be 
 plunged into the centre of the charge to a depth of 
 2 or 3 yards, without being carbonised, while the 
 materials adjoining the wall, at the same level, are at a 
 red heat. The descent of the charges, however, takes 
 place under precisely opposite conditions, the velocity 
 being greater at the centre than at the sides, where the 
 fragments are retarded by friction against the wall. 
 It therefore appears that the central portion of the 
 column of materials is likely to be imperfectly heated 
 in its passage downward, and to arrive in the region of 
 fusion in an unprepared state. 
 
 When the charges are of ore and fuel, deposited uni- 
 formty in the throat of the furnace in parallel layers, 
 the increased velocity of descent at the centre causes the 
 middle of an upper layer to overtake the sides of that 
 preceding it, so that at a certain depth below the mouth 
 the contents of the furnace are more or less completely 
 mixed. But for this circumstance, it would be impos- 
 sible to maintain a uniform heat in the hearth, which 
 would become alternately hot and cold, according to 
 whether fuel or burden happened to be in front of the 
 twyers. 
 
 In large furnaces, where it is necessary to drop the 
 charges from a certain height into the throat, the dis- 
 tribution of the materials becomes complicated by the 
 nature of the upper surface of the column in the shaft, 
 which may be either a cone raised in the centre, an 
 inverted or conical funnel depressed in the middle, or a 
 combination of both, such as a conical ring, according 
 to the method of charging employed. The charges, 
 therefore, instead of being deposited in parallel layers, 
 have to accomraodate themselves to the inclined surface 
 of the preceding one. 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 225 
 
 In the simplest of the above cases the charge is 
 dropped into the centre of the throat, and forms a 
 conical heap, sloping outwards to the circumference at 
 an angle varying, with the nature of the materials, 
 from about 35 to 40, the latter being the maximum 
 inclination of the talus formed by coke. Owing 
 to differences of form and density, the fragments 
 of ore and fuel take up different positions in the 
 furnace, the former usually remaining in the place 
 where they first strike the surface of the column, while 
 the lighter and more voluminous masses of fuel roll 
 down the slope until they have established a talus at the 
 proper angle of repose. It will easily be seen, there- 
 fore, that this is the worst possible combination, the 
 fuel being mainly distributed towards the circumference, 
 where there is a comparatively free passage for the gases, 
 while the ore remains in a dense column, impenetrable 
 at the centre, and descends without being properly 
 heated. When coke is used, the friction of the frag- 
 ments against the wall is so great as to increase the 
 tendency to form obstructions, or scaffolds, and theii 
 attendant evil, known as slips, when the charge falls, 
 owing to the removal of the obstruction, by gradually 
 increasing pressure from above, and the removal of 
 supports below. The ore in the centre, by its greater 
 velocity of descent, passes through the fuel charged 
 before it, producing an inversion of charge, so that the 
 slags change irregularly from white to black, according 
 to the preponderance of ore or fuel at the twyers. 
 
 When the charges are thrown in close to the circum- 
 ference of the throat, the surface of the column of 
 materials forms a conical cup, the lighter fragments 
 rolling inwards towards the centre, while the ore re- 
 mains at the outside. The tendency is, therefore, for 
 
 L3 
 
226 METALLURGY OF IRON. 
 
 the fuel and larger masses of ore to collect in the 
 middle, where it forms a column, which, on account of 
 its ready permeability as compared with the more 
 densely-packed ore at the sides, gives a more equable 
 draught over the entire horizontal section of the shaft, 
 at the same time that the bulk of the ore descends 
 slowly through the region of maximum heating by the 
 gases, both conditions tending to uniformity of working 
 and economy of fuel. When the throat is very wide, 
 however, and the furnace low, the draught at the 
 centre may become too strong, leading to an unneces- 
 sary consumption of fuel by diverting the gases from 
 the sides. The continual contact of metallic oxides has 
 also an injurious effect upon the lining of the furnace, 
 as the silica of the bricks is liable to combine with 
 protoxide of iron, forming a fusible silicate, by which 
 they are rapidly destroyed. 
 
 When a conical funnel or charging plates are used, 
 the surface of the column in the furnace presents an 
 annular ridge, sloping both towards the centre and the 
 circumference, the ores occupying the crest of the ring, 
 while the fuel and larger blocks are intermixed at either 
 side. This is by far the most favourable condition for 
 uniform working, as the charge and fuel are more per- 
 fectly mixed than by either of the preceding methods. 
 The use of the movable cones below the funnel, as in 
 the ordinary cup-and-cone arrangements, corrects the 
 tendency to accumulations at the centre, which is ex- 
 perienced when the charging funnel is too much con- 
 tracted at its lower end. 
 
 In Sweden, charcoal furnaces with narrow throats 
 are charged by hand, the richer magnetic ores broken 
 into small pieces are placed in a ring close to the wall, 
 while the more siliceous hematites and specular ores, as 
 
OF THE BLAST FURNACE AND ITS ACCESSORIES. 227 
 
 well as the limestone flux, are spread uniformly over the 
 surface. The charges are weighed in a large wrought- 
 iron scoop with a long wooden handle, which is sus- 
 pended by a chain above the top of the furnace. 
 
 Tapping. The molten metal accumulating in the 
 hearth of the furnace is removed at regular intervals 
 by tapping, or piercing a hole through the lower part 
 of the dam, and allowing the metal to flow into sand or 
 cast-iron moulds placed in front of the furnace. Before 
 tapping, the blast is shut off, and the tymp stopping 
 removed. The tap-hole is opened by driving in the 
 point uf a wrought-iron bar, which is held by one man, 
 while another strikes the end with a sledge hammer 
 if necessary. The moulds, or pig beds, usually consist 
 of a series of furrows in the sand of the casting floor, 
 moulded by wooden cores of a D-shaped section. The 
 curved side is placed downwards, and usually has the 
 name or mark (brand) of the works attached to it. The 
 moulds are arranged in parallel series on either side of 
 a central feeder, known as a sow ; and as soon as one 
 series is filled, the current is allowed to flow into the 
 next, and so on until the cast is completed. In Sweden 
 cast-iron moulds are generally used instead of sand. 
 
 When the ores contain lead, a certain quantity may 
 be obtained in the metallic state by tapping the hearth 
 at the lowest possible point, or by making a hole below 
 the hearth bottom, and collecting the metal which finds 
 its way through the joints of the stones. In. the latter 
 case a small fire is kept burning in the hole to prevent 
 the lead from solidifying, and it is then allowed to 
 accumulate until a sufficient quantity has been obtained 
 for a cast. 
 
 Blowing in. When a furnace is quite new, the whole 
 of the masonry must be very carefully dried before it 
 
228 METALLURGY OF IRON. 
 
 can be lighted. This may require several weeks, ac- 
 cording to the state of the atmosphere and the nature 
 of the materials employed. When perfectly dry the 
 hearth is filled with wood, and the upper part of the 
 furnace, to the top of the boshes, with coke, which is 
 then lighted from below. As soon as the fire has burnt 
 through to the surface a light charge of ore is given, 
 which is repeated when the fire reappears at the top. 
 
 Twelve hours after lighting, a grating of bars, carried 
 by an external bearer laid across the rack plates of the 
 hearth, is placed within the furnace, a little below the 
 level of the tymp ; the column of materials being thus 
 supported, the cinders and ashes of the coke filling the 
 hearth are then removed, and the air passing through 
 the grate bars, revives the combustion in the upper 
 part of the furnace. When the lower part of the mass 
 is glowing, the bars are withdrawn, and the ignited 
 materials are allowed to fall into the hearth. The fire 
 is then slackened by stopping up the fore-hearth as 
 before. The same process is repeated at the end of every 
 twelve hours, or if it is desired to get the furnace in 
 blast quicker, every six hours. 
 
 As soon as the first charge gets down to the hearth 
 the dam and twyers are fixed in position, and the blast 
 is turned on, cold air, and nozzles of a reduced diameter, 
 being adopted at first. The furnace is then filled to 
 the throat, as if in regular work ; but the weight of the 
 charges, as well as the temperature of blast and diameter 
 of twyers, must be gradually increased, so as to get to 
 the proper burden in about seven or eight days. 
 
 \> hen several kinds of ore are at hand it is well to 
 commence with the poorest, as for the same volume of 
 charge the burden will be lighter. 
 
 The above is the old method of scaffolding, whicli is 
 
OF THI BLAST FURNACE AND ITS ACCESSORIES. 229 
 
 still used in France. In England a more rapid plan is 
 adopted. The top of the wood in the hearth is covered 
 by a considerable quantity of coke, followed by alternate 
 layers of coke and limestone, the latter for fluxing the 
 ash of the fuel, until the furnace is one- third full. 
 When the fire is well started, small charges of ore are 
 added, and the blowing is commenced with twyers of a 
 reduced area. If properly managed, grey iron and 
 clean cinders may be obtained from the beginning ; 
 but for this purpose it is essential not to increase the 
 burden too rapidly, or to drive too hard at first. 
 
 Blowing out. When a furnace is to be put out of 
 blast, it is advisable to reduce the charges as much as 
 possible for a short time before, in order to get tho 
 hearth as hot as possible, so as to remove any metallic 
 obstructions. The gas tubes, and all metal fittings of 
 the throat, are then removed, and the charging being 
 stopped, the contents of the furnace are entirely lique- 
 fied by the last charge of fuel. The last tapping must 
 be made from as low a point as possible. 
 
 The sides and bottom of the hearth are often found 
 to be covered with masses of imperfectly- agglomerated 
 malleable iron, the so-called bears, wolves, or sows, and 
 isolated crystals, or even large masses of a copper- red 
 compound, formerly supposed to be metallic titanium, 
 but which has been shown by Wohler to be a cyano- 
 nitride having the composition Ti C 2 JN" + 3 Ti 3 N. 
 
 Stoppage of Furnace. It may sometimes happen, 
 through failure of the blast engine, or a deficiency of 
 materials, that a furnace must be stopped for some 
 time. This is done by closing up the throat and all 
 tne twyer huies hermetically with sand or clay. If the 
 charges have been previously diminished to a certain 
 extent, so as to keep a good "body of fuel in the furnace, 
 
230 METALLURGY OF IRON. 
 
 it may be stopped for about a week without serious 
 inconvenience ; but if the blast be interrupted for a 
 longer period, the cooling takes place to such an extent 
 that the furnace becomes blocked up, and would pro- 
 bably be obliged to be abandoned. 
 
 CHAPTER IX. 
 
 CAPACITY AND PRODUCTION OF BLAST FURNACES. 
 
 THE greatly-increased production of modern, as com- 
 pared with older furnaces, is due partly to their much 
 larger size, and partly to more rapid driving, produced 
 by giving more blast. No general rule can be laid 
 down as to the time necessary for complete reduction 
 of the ores previous to their actual fusion and the 
 separation of metal and slag by liquation, as it is 
 obviously dependent upon many variable elements, such 
 as the greater or less density of the ores and fuel, the 
 richness of the former, whether they are readily 
 reducible, or have a tendency to scorification, &c. This 
 point must, therefore, be determined by actual expe- 
 riment for each particular furnace, by varying the 
 amount of blast and the burden of ore and fluxes, 
 until the particular result required, either in respect 
 to quality or quantity of produce, is obtained. Other 
 things being equal, the time of reduction will be 
 lessened the more perfectly the materials are exposed 
 to the action of the upward gaseous current. It there- 
 fore becomes of the greatest importance to render the 
 flow of gases as uniform as possible throughout the 
 mass, by the use of proper charging and gas-collecting 
 appliances. Especial care must be taken that no 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 231 
 
 hindrance is offered to the free efflux of the current 
 at the top of the furnace. For this reason, these 
 methods, based upon the collection of the gases above, 
 or in the centre of the charge, are to be preferred to 
 such as employ lateral flues, penetrating the wall below 
 the level of the throat, whereby the current is diverted, 
 without being allowed to give up its heat to the upper 
 part of the column of materials above the flues. 
 
 An increase in the volume of blast, keeping the 
 pressure constant, has a tendency to put the furnace 
 on white iron. By increasing both pressure and tem- 
 perature, on the other hand, especially with refractory 
 ores, greyer or more highly-carburised iron is likely to 
 be produced. 
 
 In the table on page 199 the cubic contents and daily 
 make of a series of furnaces are shown, together with the 
 effective volumes required to produce one ton daily in 
 each case. 
 
 The quantities in the last column but one cannot be 
 fairly paralleled with each other, without taking into 
 account the differences in the nature of the materials 
 employed. Thus, in Nos. 1, 2, and 4, the ores are 
 treated almost without fluxes, so that the production of 
 slag is reduced to a minimum, whereas in the large? 1 
 English and Welsh furnaces, working with a mixed 
 burden, the weight of slag considerably exceeds that 
 of the iron made. The descent of the charge is quickest 
 in the Styrian furnaces, where rich and easily-reducible 
 spathic ores pass through the furnace in four and a half 
 or five hours. In Wales, on the other hand, in some 
 instances, the charges do not arrive in the hearth until 
 forty-two hours after the time of charging. In Cleve- 
 land the time of descent is about thirty- six hours; while, 
 
TABERG 
 
 Fig. 21. Comparative sections of Maet furnaces 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 233 
 
 O5O<^COtO-'O<OCO 
 
 T ?o~ 2j o P t 3 " 1 2 *i 3- &i* 
 
 Iilll I Hit 
 
 1! HIi I It 1:11 
 
 iff if- Kit 2" 1 T 
 
 " 
 
 ^p PT-P ( 
 
 C& 1 'CDO''OO 
 
 |? 
 ?t 3:^^: 
 
 OOO 
 
 9 9 
 
 |.B| , 
 
 CD O ST CD I 1 
 
 O 
 
 Cubic contents, 
 feet. 
 
 ooooosoooiooi 
 o 
 
 Daily make, 
 tons. 
 
 COI-'t-'bO 
 
 tCObOl-il-'tO K) H-'l-' 
 O-4COCO CTi rfi- O5 1 'COOiCi 
 
 ^aooco o GO o 005100 
 
 05 tO 
 
 Effective volume 
 
 in feet 
 per ton made. 
 
234 METALLURGY OF IRON. 
 
 in the older blackband furnaces in Scotland, it varies from 
 two and a half to three and a half days. 
 
 The nature of the work done by blast furnaces can 
 only bs understood by examining the conditions of pro- 
 duction prevailing in different districts. The following 
 examples give the working details of a few examples 
 selected is types from various localities : 
 
 At Eisenerz, in Styria, the furnaces consist of two 
 truncated cones, with a very narrow throat, and 
 are distinguished from the ordinary blast furnace by 
 being without a fore-hearth, the metal and slag being 
 allowed to collect in the hearth, which is comparatively 
 shallow, and are tapped off together at short intervals, 
 the number of casts varying from 5 to 16 in twenty- four 
 hours. The ores are chiefly spathic, poor in manganese, 
 partly pure, and partly altered into brown hematite. In 
 order to get rid as completely as possible of the sulphur 
 due to the presence of pyrites in small quantities, they 
 are allowed to weather for two, three, or more years 
 after roasting. The amount of iron varies from 35 
 to 55 per cent. The object sought to be attained is the 
 production of white iron, for conversion into bar iron, 
 from rich and easily-reducible ores, with a minimum 
 expenditure of fuel (charcoal). This is done by work- 
 ing under a very heavy burden, the tendency to obstruc- 
 tions caused by this proceeding being counteracted by 
 giving charges of fuel alone at regular intervals. Some 
 varieties of ore are of the self- fluxing kind ; but as a 
 rule they contain a considerable quantity of lime, re- 
 quiring the addition of siliceous and aluminous fluxes, 
 such as clay or clay slate. The following are the 
 charges and yields of the two furnaces whose sections 
 are given in Fig. 21 : 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 235 
 
 1. Von Fridau's Furnace, Vorderriberg. The charge 
 consists of 5 to 6 cwt. of roasted ore, 10 per cent, of 
 clay, and 8 to 10 Ibs. of washed metal, i.e. granulated 
 pig iron, recovered from the slag by stamping and 
 washing. The fuel is measured ; 2 tubs, or 15^ feet, 
 or about 101 Ibs. of soft pine-wood charcoal being 
 employed per charge. The burden of ore is gradually 
 raised from 3 to 6 cwt. per charge, and then diminished 
 similarly, a blank charge of fuel being given at 
 each change. The daily production is from 18 J to 
 20 tons. The twyers plunge or incline at an angle 
 of 5, so that the furnace fulfils, to some extent, the 
 functions of i* refinery. 
 
 2. Von Fischer's Furnace, Vor dernier g. This is one 
 of the smallest furnaces in the world. (See section, Fig. 
 21). The usual charge includes 223 Ibs. ore, 15 Ibs. 
 clay, and 4 Ibs. of washed metal, to Ij tub (13| 
 cubic feet or 95 Ibs.) of charcoal. The daily produc- 
 tion is 7 \ tons ; the furnace is tapped at intervals of 
 one and a half hours, fourteen charges being made dur- 
 ing the same period, including a blank one, i.e. of 
 fuel without burden. 
 
 These furnaces are driven at a very high speed. The 
 first tapping takes place twelve hours after lighting, 
 and afterwards at intervals of two to two and a half 
 hours. The burden of ores smelted per tub of 7J feet 
 of charcoal varies from 170 to 220 Ibs. with cold, and 
 from 220 to 250 Ibs. with hot blast. The consumption 
 of charcoal is from 65 to 70 per cent, of the weight 
 of the metal produced, or from 13 J to 14 cwt. per 
 ton. 
 
 The ores are well adapted for the production of 
 spiegeleisen, though they contain less manganese than 
 those of a similar kind smelted in Siegen ; but owing 
 
236 METALLURGY OF IRON. 
 
 to the price of fuel, it is not always made. The 
 slags usually contain a considerable quantity of prot- 
 oxide of manganese (from 10 to 21 per cent.), and 
 often nearly as much protoxide of iron, owing to the 
 small amount of lime employed in fluxing. In some 
 instances, a certain quantity of ankerite (carbonate of 
 lime, magnesia, and protoxide of iron) is added to every 
 fourth or fifth charge. 
 
 In the Siegen district the ores smelted are principally 
 spathic and brown hematite, with a consider able quantity 
 of manganese, together with red schistose hematite, 
 partly raised in the neighbourhood, and partly brought 
 from Nassau. The products are white and grey pig metal 
 and spiegeleisen, all of which are employed in steel- 
 making ; the first (weissstrahlig or rohstahleiscn) in the 
 open fire or puddling furnace, and the others in the 
 Bessemer process. Formerly the furnaces were small, 
 and chiefly worked with charcoal, but in those of newer 
 construction the use of coke and hot blast is found to 
 be attended with greater regularity in the composition 
 and quantity of the products. The following examples 
 give the working details of two of the largest and most 
 improved furnaces : 
 
 Heinrichshutte. The ordinary charge contains, by 
 measure : 
 
 f roasted spathic ores . . 7 cwt. 
 
 f brown hematite . . . 4 
 25 to 30 per cent, limestone . 3 ,, 
 
 The fuel is coke from the Ruhr coal-field, containing 
 from 9 to 10 per cent, of ash. Each charge weighs 14 
 cwt., and contains from 44 to 48 per cent., correspond- 
 ing to a burden of 36 cwt. of ore and flux per ton of 
 toetal. The daily number of charges is from 38 to 40, 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 237 
 
 Tho blast is supplied through three twyers, that at 
 the back being 2J, and those at the sides 2nr inches 
 diameter. The pressure is 3f Ibs. per square inch, and 
 the temperature from 270 to 300. About 26 tons 
 of a white lamellar metal (rohstahldsen] , suitable for 
 conversion into steel, and sheet and wire iron, are pro- 
 duced daily, with a consumption of from 20 to 22 cwt. 
 of coke per ton. 
 
 At Charlottenhutte the charges for spiegeleisen are 
 of the following composition : 
 
 cwt. 
 
 JRoasted spathic ores . . 28*8 ) yielding from 
 Eaw brown hematite . . 7 -2 ) 44 to 45 per cent, 
 limestone . 9'0 
 
 Total charge . . . 45-0 
 Coke .... 20'0 containing 8 percent. 
 
 of ash. 
 
 Daily number of charges, 36 ; produce, 30 tons ; con- 
 sumption of coke per ton, 22 to 23 cwt. ; number of 
 twyers, 3 ; back, 3 inches ; sides, 3f inches diameter ; 
 pressure of blast, 3| Ibs. per square inch ; temperature, 
 280 to 300. When working on white forge pig, the 
 charge is increased by the addition of Nassau red 
 hematite to 50 cwt., and the produce to 35 tons. 
 
 The production of spiegeleisen is facilitated by the 
 prevalence of a high temperature in the region of the 
 hearth, the use of hotter blast being found to increase 
 the quantity of manganese reduced. The metal produced 
 under the conditions given above contained 8 per cent, 
 of manganese, which was reduced to 4 per cent, when 
 the temperature of the blast was allowed to fall to 
 100. 
 
 The slag must be as nearly as possible neutral, t.e 
 
238 METALLURGY OF IRON. 
 
 having the oxygen of the bases equal in amount to that 
 of the silica ; but as the silicates of lime and alumina 
 of this form are extremely refractory, the requisite 
 fusibility is attained by the partial substitution of other 
 bases, such, as magnesia, but more particularly protoxide 
 of manganese. Silicate of protoxide of manganese, re- 
 quiring a very high temperature for its reduction by 
 carbon, does not exercise a decarburising influence 
 on molten cast iron to the same extent as the corre- 
 sponding silicate of protoxide of iron. 
 
 Owing to their basic character, the slags have a 
 tendency to corrode the sandstone hearth of the furnace 
 very rapidly. This is counteracted, to a certain extent, 
 by the use of water blocks surrounding the exterior of 
 the hearth at several different levels. 
 
 The amount of manganese reduced also depends upon 
 the state of oxidation in which it exists in the ores, 
 being greatest when spathic ore is used, and least when 
 supplied in the form of manganesiferous hematite. 
 Formerly the spiegeleisen of Miisen was produced by 
 the treatment of the Stahlberg spathic ore without flux ; 
 but since the introduction of limestone into the charge, 
 the metal is much richer in manganese. 
 
 The furnaces used in Sweden are in many respects 
 similar to the Biauofen of Styria, the fore-hearth being 
 small and narrow. Their dimensions are usually small, 
 varying from 600 to 2,300 cubic feet. The largest, 
 at Sandviken, near Gefle, is 52 feet high, 9J feet 
 wide at the boshes, and 6 feet at the throat, with six 
 twyers, four of which are used at one time; the other 
 two are in the tymp, South Wales fashion. The slags 
 and metal are drawn on opposite sides of the hearth, 
 an arrangement similar to that of the furnace at Safvenas, 
 Fig. 4, so that the iron may be run directly into the 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 239 
 
 Bessemer converters. The clay and quartz lining of 
 the hearth is from 6 to 8 inches thick ; it consists of 
 from 4 to 6 parts of quartz, mixed with 1 of fire- 
 clay. 
 
 The Swedish ores vary considerably in character. The 
 best are those known as self-fluxing, i.e., containing 
 earthy materials in the proper proportions to form a 
 fusible bisilicate slag without further addition. The 
 ores of Dannemora, Langbanshytta, and Langs- 
 hytta are of this character: they contain from 50 
 to 59 per cent, of iron. At the last-named furnaces, 
 the charge, with the addition of from 3 to 5 per cent, 
 of limestone, or blast-furnace slag, contains at times as 
 much as 60 J per cent, of iron. As a general rule, 
 the more quartzose hematites and micaceous ores are 
 mixed with calcareous magnetites, and fluxed with 
 dolomitic limestone, the average percentage of the 
 charges being from 35 to 52 per cent. The maximum 
 amount of flux, 25 per cent, of limestone, is used in 
 smelting the siliceous hematite of Nora ; and at Taberg, 
 where the ore is a serpentine impregnated with mag- 
 netite, and the charge contains only 20 per cent, of iron. 
 
 The temperature of the blast does not exceed 200, 
 the pressure varying from 10 to 15 lines of mercury, 
 or at most 20, in the newer furnaces. The gases for 
 heating the blast are drawn through an opening in the 
 side of the furnace, about 12 or 14 feet below the 
 throat ; the stoves are of the horizontal, serpentine, or 
 Wasseralfingen pattern, with pipes of circular section ; 
 the coil rarely containing more than three or four 
 turns. Cold blast is only used at Finspong, in the 
 manufactory of gun-foundry iron ; even the Danne* 
 mora furnaces are now worked with blast heated to 
 80 or 100 
 
240 METALLURGY OF IRON. 
 
 The average weekly production of the Swedish 
 furnaces ranges from 700 to 1,400 centners (24 
 centners = 1 ton). In excess of these yields are those of 
 Langshytta, 2,800 ctr. ; Sandviken, 2,500 ctr. ; and 
 Langbanshytta, 1,800 ctr. At Taberg, on the other 
 hand, the amount is as low as 600 ctr. The furnaces 
 are, as a rule, only kept in blast during the winter 
 months, in 1864 the average was 150 days, when the 
 ores and fuel can be easily brought to the works by 
 means of sledges. At the mouths of the Lapland rivers, 
 some of the furnaces are in connection with saw-mills, 
 the blast-engine boilers being fed with the waste slabs 
 and sawdust ; the ores and fluxes, in such cases, being 
 brought from the south in the summer time by sailing 
 vessels. 
 
 The consumption of charcoal varies with the nature 
 of the ore, the average for the whole country being 
 from 16 to 17 cwt. per ton of white or mottled 
 forge pig, and about one- third more, or from 21 to 22 
 cwt. per ton, of grey metal, suitable for foundry or 
 Bessemer steel purposes. At Langshytta, the con- 
 sumption is as low as 13 \ to 14 cwt., making white 
 and mottled iron. The poor ores of Taberg require as 
 much as 50 or 60 cwt. per ton. 
 
 The charcoal furnaces of Lake Superior are notice- 
 able for their large productions. At Greenwood fur- 
 nace, near Marquette, two classes of ore are smelted 
 namely, brown hematite, containing an average 40 per 
 cent., and slaty red hematite, or specular schist, with 
 60 per cent. ; the former, although poorer, is preferred, 
 as being more easily reducible than the harder slaty 
 ore. The two qualities are mixed to yield 55 per cent, 
 of pig iron. The furnace is 40 feet high, 11 feet 
 diameter at the boshes, and 4 feet at the throat ; the 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES 241 
 
 gases are collected in a narrow ring flue, enclosed by 
 an iron cylinder, remaining open. The blast, at a 
 temperature of 330 and a pressure of 1J to 2 Ibs. per 
 square inch, is introduced through two twyers of 3J 
 inches in diameter on opposite sides of the hearth. A 
 variegated crystalline limestone is used as flux, to the 
 amount of about 10 per cent, of the weight of the ore. 
 The fuel is hard wood, principally maple charcoal, the 
 consumption being at the rate of 125 bushels, weighing 
 from 16 to 20 Ibs. each, or about 25 cwt. per ton of 
 pig iron. The ores are not roasted, but all the materials 
 are reduced to the size of ordinary road metal by a 
 Blake's rock breaker previously to charging. The 
 daily produce in July, 1865, before the furnace had 
 arrived at its full make, was from 16 to 18 tons, mostly 
 small-grained, dark grey pig, suited for Bessemer steel- 
 making and foundry work, especially chill casting, 
 such as railway wheels. At "Wyandotte Iron Works, 
 near Detroit, in a furnace of similar dimensions, 
 the consumption of light-wood coals is 140 bushels of 
 14 Ibs. weight each per ton. The charges are 500 Ibs. 
 of red slaty ore, 40 Ibs. of limestone, from the Niagara 
 formation, which is supplied in the form of rolled 
 pebbles, and 40 Ibs. of forge cinders ; the average 
 yield being 65 per cent. 
 
 The large amount of fuel required by these fur- 
 naces has already made a very decided impression on 
 the surrounding timber. The average yield per acre of 
 the best timber land on Lake Superior is often 50 to 
 60 cords of 128 cubic feet measurement, or about 
 2,700 bushels ; a quantity only sufficient to make 20 
 tons of pig iron. So that the daily supply of a single 
 furnace necessitates the clearing of an acre of forest ; 
 or, supposing it to be put down in the centre of a 
 
242 METALLURGY OF IRON. 
 
 uniformly- wooded district, and to make 16 tons daily, 
 two years' working would be sufficient to clear a circle 
 of a mile in diameter. It is evident, therefore, that 
 even in a densely- wooded country a permanent supply 
 ff fuel cannot be looked for except where the works 
 are placed within reach of rivers or navigable waters. 
 
 In South Staffordshire the make is chiefly grey pig 
 for forge purposes, which is afterwards converted into 
 bars, plats, and other small varieties of merchant iron. 
 The ores employed are partly " native mine/' i.e. clay 
 ironstones from the coal measures, and partly brown and 
 red hematites from North Staffordshire, Lancashire, 
 and other parts. Forge cinders are extensively used 
 in the production of common hot blast metal, but the 
 best mine pigs are still made with cold blast and coke. 
 According to Jones the annual consumption of this 
 district is as follows : 
 
 Tons. 
 
 Native mine (clay ironstones of the coal measures) . 948,500 
 Brown hematite, "hydrate," or Froghall calcareous 
 
 brown hematite . 368,000 
 
 lied hematite, Ulverstone 50,000 
 
 Northamptonshire brown iron ores .... 200,000 
 
 North Staffordshire argillaceous carbonate and blackband 180,000 
 
 Forge and mill cinders . 150,000 
 
 1,896,500 
 
 The coals of South Staffordshire are of a non-caking 
 class, yielding only a slightly coherent coke, from the 
 absence of binding qualities ; therefore the slack cannot 
 be coked alone. Of the two principal seams used for 
 iron-making, the thick yields 54 per cent, by weight of 
 coke, with 0'31 of sulphur and 4'18 of ash ; the lower, 
 or heathen coal, contains 0'51 of sulphur and 4*58 of ash. 
 Generally the fuel is used partly raw and partly coked. 
 The pressure of blast varies between 2J to 3 Ibs. per 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES, 243 
 
 square incli, and tlie temperature from. 300 to 330, 
 except in the small number of cold blast furnaces. 
 
 The flux used is principally Silurian limestone from 
 Dudley and Wenlock Edge, and carboniferous limestone 
 from North Staffordshire and Derbyshire. 
 
 The average consumption of coal per ton of metal made 
 is for hot blast furnaces from 55 to 60 cwt., and for cold 
 blast from 60 to 70 cwt., or rather, the corresponding 
 equivalent in coke, besides 2 cwt. of small for cal- 
 cining, and 15 to 22 cwt. used in the hot blast stoves 
 and steam boilers, very few furnaces in this district 
 being provided with gas-saving apparatus. 
 
 The average weight of the charge per ton of pig 
 iron is 
 
 48 cwt. Coal-measure ores. 
 
 7 ,, Red hematite. 
 14 ,, Limestone. 
 
 The average yield of 119 furnaces in blast in 1866 is 
 stated to have been between 120 and 150 tons each per 
 week ; the largest make from 180 to 250 tons weekly ; 
 but there are only a small number in this class. 
 
 The produce is classified into six numbers as 
 follows : 
 
 Kos. 1, 2. Grey foundry pig. 
 3, 4. Grey forge pig. 
 ,, 5, 6. Mottled and white forged pig. 
 
 According to quality and materials employed, the 
 following scale is adopted in South Staffordshire : 
 
 Common forge pigs. 
 
 ,, foundry pigs. 
 Best foundry pigs. 
 
 Mine pigs, smelted from ores without cinders. 
 Best mine pigs, special brands. 
 Hydrates, made from Froghall brown hematite. 
 Cold blast pigs. 
 
 M2 
 
244 METALLURGY OF IRON. 
 
 The general conditions of working in the blast fur- 
 naces of South Wales are in many respects similar to 
 those of South Staffordshire, especially as regards the 
 ores which are partly raised on the spot, and partly 
 brought from other districts, often at a considerable 
 distance. The staple product is white forge pig, which 
 is in great part used in the manufacture of rails in the 
 local forges. The higher qualities of metal are taken 
 by the tin-plate works, and a few furnaces make cold 
 blast pig for founders' use. The following are the 
 principal varieties of ores : 
 
 1. Native 'mine, chiefly argillaceous carbonates, with 
 some blackband. 
 
 2. Brown hematites from Llantrissant, Forest of 
 Dean, Cornwall, and Northamptonshire. 
 
 3. Red hematite from Cumberland. 
 
 4. Spathic ore from Somersetshire. 
 
 Brown and red ores from Spain, both ordinary and 
 manganiferous, as well as the rich magnetic and specu- 
 lar ores of Elba and Algeria, are also largely used. 
 In the eastern or bituminous coal district, the fuel is 
 partly raw coal and partly coke, except in the case of 
 cold blast furnaces, where the latter is exclusively used. 
 Further westward, in the neighbourhood of Swansea, a 
 small number of furnaces are worked with anthracite. 
 The impurities in some of the principal varieties are as 
 follow : 
 
 Sulphur. Ash. 
 
 Anthracite . . . 0*7 per cent. 9-14 per cent. 
 
 Coke, Blaenafon . . 0'74 5'35 
 
 ,, Pontypool . . 0-76 ,, 12-15 
 
 Forge and mill cinders are largely used in the pro- 
 duction of white iron for rails. The following area 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 245 
 
 few of the principal varieties of charges and consump- 
 tion of materials per ton of metal produced : - 
 
 Cold blast pigs. Blaenafon. Pontypool. 
 
 Argillaceous ores (raw) . 72 cwt. (calcined) 46f cwt. 
 
 Forest of Dean hematite . 9 
 
 Limestone . . . 20 ,, 24 ,, 
 
 Coke . . . . 64* 50i 
 
 The average weekly make at Blaenafon is 104J tons. 
 The fuel consumed corresponds to between 3 and 4 tons 
 of coal per ton of iron. 
 
 Truran gives the following details of charges em- 
 ployed at Dowlais for different makes of pig iron per 
 ton : they refer to a period several years back : 
 
 Qualityof-netal. Foundry. nte C_ 
 
 Calcined mine . . .48 cwt. 28 cwt. 
 
 Red hematite . . ,, 10 ,, 16 cwt. 
 
 Forge and refinery cinders . ,, 10 25 ,, 
 
 Limestone . . . . 17 ,, 14 ,, 16 ,, 
 
 Coal 50 42 36 
 
 Weekly make . . . 130 tons 170 tons 190 tons 
 
 The capacity of the furnace is about 8,500 cubic feet : 
 the blast is supplied at a pressure of 3 Ibs. per square 
 inch. The estimated time of descent of the charges is 
 from forty to forty-six hours. 
 
 In 1863, at the same works, the consumption of coal 
 per ton of mine pig made from mixtures in variable 
 proportions of argillaceous ore, red and brown hematite, 
 was reduced to between 24 and 29 cwt., the make of 
 the furnace ranging from 174 to 280 tons, in round 
 numbers, per week. The larger yield, corresponding 
 to the smaller consumption of fuel, was due to the in- 
 c.veased richness of the charge from the preponderance 
 
246 METALLURGY OF IRON. 
 
 of red ore. In the newer large furnaces producing whito 
 iron the make is often considerably higher, and ranges 
 from 250 to 300 tons weekly. They are mostly of large 
 capacity, but vary very considerably in outline. A 
 common form is that having a cylindrical body and 
 domed top. The use of the cup-and-cone charger, and 
 the economising of the waste gas for steam and hot 
 blast purposes, is also very general. 
 
 In the anthracite district the furnaces are of com- 
 paratively small volume and height, though the newer 
 ones show a tendency to increase in the latter direction. 
 As has already been mentioned, the use of tall furnaces 
 is attended with difficulty, owing to the decrepitation 
 of the fuel, which gives rise to a closely-packed column 
 of materials, only penetrable by a very dense blast. 
 Probably Rachette's pattern of furnace might be 
 applied with advantage in smelting with anthracite. 
 The average consumption of fuel is about 44 cwt. per 
 ton of pig iron, but in one instance at Yniscedwin it 
 has recently been brought down to as low as 18 cwt. 
 
 The total number of furnaces in blast in South Wales 
 in 1865 was 118; the average weekly make of each 
 was 133 tons, not including 9 anthracite furnaces, 
 averaging 62 tons each. 
 
 The Cleveland district is remarkable for the large 
 size and height of its furnaces, which are entirely 
 worked with hard coke from the south of Durham, 
 containing on an average from 0'6 to 0'8 per cent, of 
 sulphur, and from 4J to 8 per cent, of ash. The ore is 
 principally the green argillaceous carbonate named 
 after the district, whose composition has already been 
 given at p. 78. In some instances red hematite is 
 used as a mixing ore, but to a very slight extent. In 
 the raw state the Cleveland ore contains from 29 to 32 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 247 
 
 per cent, of iron, which is increased to 40 per cent, on 
 calcination. The following figures were given by 
 Beckton as the average composition of charges in 1864 
 per ton of pig iron : 
 
 70 cwt. Cleveland stone. 
 
 15 limestone. 
 
 26 ,, coke. 
 
 10 coal for calcining, heating blast and boilers. 
 
 According to J. L. Bell the pressure of blast used in 
 1863 was from 3 to 41bs., and the temperature 300 to 
 350 : the average weekly make varied from 200 to 220 
 tons. At Consett it was from 420 to 450 tons, and 
 latterly one furnace has made 880 tons weekly for 
 several weeks in succession.* 
 
 The size of the Cleveland blast furnaces has increased 
 very rapidly in the last two or three years. In 1863 
 the average height was from 42 to 55 feet, and the 
 width of the boshes from 14 to 18 feet; but these 
 dimensions are in the newest furnaces increased to 
 between 70 and 102 feet high, with a maximum width 
 of 27 feet. The Acklam furnaces at Middlesborough, 
 which are 70 feet high, 8 feet in diameter at the 
 hearth, and 22 J feet at the boshes, with the upper part 
 of the body cylindrical, are each capable of holding 
 1,250 tons of materials, and make 350 tons of pig iron 
 weekly. In all cases a notable saving of fuel has been 
 experienced by increasing the height of the furnace, 
 the upper part of the column of materials absorbing 
 the excessive heat of the waste gases. The latter are 
 used for raising steam and heating the blast, but have 
 not as yet been applied to roasting the ores. 
 
 The average size of Scotch furnaces is stated at 
 16 feet in diameter and 55 feet in height and their 
 
 * See note on the progressive increase of the Cleveland furnaces, 
 p. 607, 
 
248 METALLURGY OF IRON. 
 
 production from 230 to 270 tons weekly. These figures 
 probably refer to the blackband districts, as in 1865 
 the average of 141 furnaces in the whole of Scotland 
 did not exceed 159 tons per week. 
 
 The largest furnaces, considered in regard to produc- 
 tion, are those of the hematite districts of Lancashire 
 and Cumberland. The total number in blast in 1865 
 was 13, with an average make of 315 tons each per 
 week. At Barrow-in-Furness, the furnaces (whose 
 section is given in Fig. 6, p. 142) are 56 feet high, 
 7 feet wide at the hearth bottom, 16 J feet at the boshes, 
 and 17J feet at the throat. The volume is 9,500 cubic 
 feet. According to Jordan, in 1864, the following 
 materials were required to make a ton of pig iron : 
 
 Ked hematite (unroasted) . . 34 34| cwt. 
 
 Coke from Durham . . . 18 18 
 
 Limestone . . . . *>" 
 
 Coal slack for stoves . . 3 ,, 
 
 The gases are partially drawn off by a central tube 
 and exhausting fans, as described at p. 180, and are ex- 
 clusively employed in firing boilers. The blast is sup- 
 plied at a pressure of 2 Jibs, per square inch, and a 
 temperature of 350, through six 3 -inch twyers, the 
 volume delivered per minute being about 7,000 cubic 
 feet. The maximum production under these conditions 
 appears to be about 90 tons per day. Ordinarily, about 
 20 tons are obtained at each cast, which takes place at 
 intervals of six hours, giving a total amount of 80 tons 
 daily. The iron made is converted on the spot into 
 Bessemer steel. 
 
 At Kirkless Hall, near Wigan, the same ores are 
 smelted under generally similar conditions to those last 
 mentioned. A pair of new furnaces recently erected, 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 249 
 
 but not yet lighted, are 80 feet high and 20 feet in 
 diameter, with closed tops and cup-and-cone chargers ; 
 their capacity is 22,000 cubic feet, or about two and 
 a half times as great as the Barrow furnaces. In 
 Cumberland the addition of a proportion of the alumi- 
 nous ore of Belfast to the charge is found to have an 
 advantageous effect. 
 
 In Belgium the ores smelted are chiefly red and 
 brown hematite. The former, a mixture of specular 
 and micaceous ore, is known as violet mine ; the latter, 
 or yellow mine, is mostly ochreous and earthy : 
 requiring to be subjected to the processes of crushing 
 and dressing before it is fit for treatment in the 
 furnace. A variety of spathic ore, containing a con- 
 siderable proportion of carbonate of zinc, found at 
 Angleur, near Liege, has the reputation of making an 
 extremely strong iron. A large proportion of the 
 brown hematite is obtained from the oolitic formations 
 in Luxemburg. In 1864 the number of furnaces in 
 blast and the total production were as follow : 
 
 46 coke furnaces produced . 444,430 tons. 
 6 charcoal furnaces produced . 5,545 ,, 
 
 corresponding to a weekly make of 186 tons per furnace 
 on coke, and 18 tons on charcoal : the latter figure is 
 probably too low for the period of actual working, as 
 these furnaces are rarely in blast continuously for the 
 whole year. 
 
 The anthracite furnaces of Pennsylvania are remark- 
 able for the high pressure (from 6J to 7J Ibs. per 
 square inch) of blast employed. The ores are similar 
 to the rock mine of Sweden i.e., massive magnetite 
 and hematite, yielding from 50 to 60 per cent, of iron. 
 
 M3 
 
250 METALLURGY OF IRON. 
 
 The following are the charges and produce of two 
 different furnaces :-^- 
 
 Lehigh. Lackawanna. 
 
 Ore . . 42cwt. . . 88icwt.(52percent.) 
 Limestone . 29 ,, 14 ,, 
 Coal , . 39| . . 33 
 Weekly make 248 tons ( No. 1,1 No. 2) 268 tons (all No. 3), 
 
 In the State of Indiana, the specular and red hema 
 tite ores from Lake Superior, Iron Mountain, and Pilot 
 Knob, in Missouri, are smelted with the so-called block 
 coal. This is a free-burning, non-caking splint coal, 
 which is highly esteemed for iron-smelting purposes, 
 and is used in the raw state. The furnaces are all of 
 moderate size, from 50 to 60 feet in height, from 12 to 
 16, across the boshes, and 5 to 6 feet in width of hearth, 
 
 At Brazil (near Indianapolis), the furnace charges 
 employed are as follows : 
 
 1,545 Ibs. mixed ores (hematite, magnetite, scrap, and 
 
 mill cinder. 
 475 limestone. 
 1,800 coal. 
 
 The yield is about 68 per cent., the furnace 
 tapped three times in the twenty- four hours. 
 
 The blast is heated by the waste gases to a tempera- 
 ture of 370 to 450, and is delivered under a pressure 
 of from three to four pounds to the square inch, through 
 seven twyers, each 3J inches in diameter. 
 
 The average daily consumption of coal is 70 tons, of 
 ore 45 tons, and of limestone 16 tons; the average 
 make of pig iron being 28 tons. The consumption of 
 coal is therefore about 2i tons per ton of pig iron 
 made, or, reducing it to its equivalent in coke, about 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 251 
 
 li tons. The conditions of working, therefore, not- 
 withstanding the high produce of the ores, are not 
 nearly so economical as regards consumption of fuel as 
 those of the Lancashire and Cumberland furnaces smelt- 
 ing hematite. 
 
 The ores used at this furnace are brought from very 
 great distances, the native ore being more expensive in 
 proportion to its produce than the richer hematite and 
 magnetite of Missouri and Michigan. 
 
 The estimated make of pig iron in the United States 
 from 445 furnaces in blast, in 1881, was as follows, 
 classified according to the fuel employed : 
 
 Tons. 
 
 Anthracite .... 1,548,627 
 Coal and Coke . . . 2,025,236 
 Charcoal .... 570,391 
 
 4,144,254 
 
 At Newark, in New Jersey, spiegeleisen is made 
 from the residues obtained in the treatment of the 
 mixed zinc and iron ores of Franklin, in the same State. 
 The ore is an intimate mixture of franklinite and red 
 zinc ore, with a massive green variety of willemite or 
 silicate of zinc ; it occurs in crystalline limestone, form- 
 ing an irregular bed, which in places is 52 feet thick, the 
 different minerals being very intimately mixed. A mix- 
 ture of finely-crushed ore, with lime and anthracite, is 
 heated in an oven-shaped calciner, having a cast-iron 
 bed, perforated with numerous narrow slits, through 
 which air is blown by a fan in sufficient quantity to 
 burn the coal and oxidise the zinc vapour as it forms. 
 The oxide of zinc produced in this process passes 
 through a long series of condensing tubes and cooling 
 
252 METALLURGY OF IRON. 
 
 chambers, the current being kept up by exhausting 
 fans, until it is sufficiently cooled to be collected in 
 bags made of cotton cloth. The residue remaining in 
 the furnace after the removal of the zinc is a black 
 cindery mass, containing the whole of the iron and man- 
 ganese of the franklinite and the silica of the willemite, 
 besides some undecomposed zinc oxide ; it is estimated 
 to contain 25 per cent, of iron, and 4 per cent, of zinc, 
 and is smelted for spiegeleisen. The furnaces employed 
 are very small, being only 20 feet high, and 7 feet across 
 the boshes ; the hot blast is of about 200 temperature, 
 and a pressure of four pounds is used. The fuel used 
 is anthracite, and some limestone is added as a flux. 
 Four blank charges of clean slags are made in every 
 twenty-four, to prevent scaffolding. Great difficulty 
 is experienced in working the furnaces, owing to the 
 large amount of zinc remaining in the ore, which 
 deposits in the gas flues at the throat, and necessitates 
 the use of an elaborate system of wrought-iron con- 
 densers for separating the oxide of zinc from the gases, 
 before they can be burnt in the hot-bkst stoves and 
 steam boilers. The oxide of zinc obtained in cleaning 
 out the condenser, being too much discoloured to use as 
 paint, is sent to the spelter furnaces for reduction, and 
 makes a very high quality of zinc. The consumption 
 of fuel is very high, being at the rate of 3J tons per ton 
 of iron. The weekly make of the furnace is about 25 
 tons. When making spiegeleisen, the slags are of the 
 usual bright green colour characteristic of manganese ; 
 but when the furnace is too heavily burdened, and 
 produces ISTo. 2 iron corresponding to the German 
 tveiss-strahlig, the colour changes to a deep brown. As 
 the proportion of manganese to iron in the ore is large, 
 the. spiegeleisen is rich in manganese. 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 253 
 
 Spiegeleisen is now largely produced, both, in Eng- 
 land and France, from, other than spathic ores, the 
 manganiferous minerals of Carthagena and Almeria, 
 in Spain and Sardinia, being principally used. These 
 contain from 10 to 40 per cent, of iron, and about the 
 same of manganese, the two metals being usually in the 
 inverse proportion ; so that by judicious mixing with 
 other hematites any desired proportion of manganese 
 may be obtained in the products, which it is customary 
 to call by the old name as long as the percentage of 
 manganese does not exceed 20 per cent., although the 
 distinctive crystalline plates are no longer apparent. 
 Higher alloys containing up to 87 per cent, of manga- 
 nese, distinguished as ferro-manganese, have been made 
 in the blast furnace in France by the Terre-Noire Com- 
 pany, and at St. Louis, near Marseilles. They are hard 
 and highly crystalline on fracture, somewhat resembling 
 sulphide of antimony ; but the production requires an 
 enormous consumption of fuel, nearly 3J tons of coke 
 per ton of metal (the blast must be heated to the highest 
 temperature attainable by fire-brick stoves), and the 
 daily yield is diminished from 50 or 60 to between 12 
 and 20 tons. The amount of manganese reduced is 
 from 60 to 70 per cent, of that contained in the charge, 
 and of the remainder a notable proportion is, as 
 shown by Jordan, volatilised, the amount found in the 
 slag being insufficient to account for the difference. 
 Spiegeleisen and ferro-manganese have also been made 
 with .charcoal in the blast furnace at Jauerberg, in 
 Carinthia, and at Schisshytan, in Sweden ; in the latter 
 case the ore was magnetite, with silicates of manganese 
 (knebelite) and manganiferous garnet. 
 
 Recent Production of Blast Furnaces. Many of the 
 figures given in the preceding pages, referring as they 
 
254 METALLURGY OF IRON. 
 
 do to periods of nearly twenty years back, are of histo- 
 rical interest only, and require to be supplanted by 
 more recent data. The increase of production in blast 
 furnaces, except in some cases where special qualities 
 of charcoal or cold-blast metal are made, has been very 
 general in most countries, as will be seen by the figures 
 given below. The cause of this progress is to be found 
 mainly in the adoption of methods that have been 
 developed in Cleveland and the north-west of England ; 
 that is, large furnaces with broad heaths and com- 
 paratively steep boshes and superheated blast, the latter 
 being due to the adoption of, fire-brick stoves of the 
 Siemens, Cowper, and Whitwell forms, which are now 
 common in every principal iron district in the world, 
 and more particularly in those making steel pigs on 
 the large scale. The use of high-speed short-stroke 
 blowing engines instead of the ponderous slow- going 
 patterns with overhead beams, also of Cleveland origin, 
 is everywhere becoming more common, the Cockerell 
 Company, of Seraing, having been very successful in 
 the design of such engines. These are now frequently 
 made in the compound type, the same steam being 
 worked exhausting in two cylinders of unequal diame- 
 ier, and the same principle of construction is adopted 
 for Bessemer blast engines. Probably about 500 tons 
 per week, or from 70 to 80 tons per day, may be taken 
 as the standard output of a modern blast furnace of the 
 first-class working upon moderate or high-class ores. 
 As regards dimensions, new furnaces usually range 
 between 65 and 85 feet in height, 16 and 22 feet width 
 in the boshes, and 7 to 9 feet in the hearth. The extreme 
 height of 100 feet, which was tried experimentally in 
 Cleveland some years since, has not been imitated 
 subsequently. 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 255 
 
 The following are examples of the present working 
 conditions of blast furnaces in Belgium : 
 
 Marchiennes, No. 2 Furnace, 52 feet high, diameter 
 16 J feet in boshes, and 5J feet in hearth. Capacity, 5,578 
 cubic feet. Working upon 38 per cent, oolitic ores 
 and forge cinder, with coke containing 15 per cent, of 
 ash, and blast at 6 inches pressure of mercury heated 
 to 400 degrees, made 75 tons of forge pig iron per day, 
 with a consumption of 22 cwt. of coke to the ton. 
 
 Luxemburg Company, No. 1 Furnace, 65 feet high, 
 23} feet diameter in boshes, and 6-J- feet in hearth. 
 Capacity, 15,536 feet. With similar ores and fuel to the 
 preceding, made 113 tons per day, with a consumption 
 of 23-6 cwt. of coke per ton of metal. 
 
 In America the make of furnaces has very largely 
 increased of late years, and in those of newer construc- 
 tion, working upon rich ores of 60 per cent, produce 
 and above, the production is in many cases far above 
 that obtained in Europe from furnaces of the same 
 size. Thus at the Edgar Thompson works, near Pitts- 
 burg, the A furnace, 65 feet by 13 feet, has made 113 
 tons, with a consumption of 1,965 Ibs. of coke per ton 
 of pig iron ; the B furnace, 80 feet by 20 feet, 208 tons ; 
 and the C furnace, of the same dimensions as the last, 
 224 tons, with a consumption of 20 cwt. of coke per 
 ton. They have once made 261 tons per day. 
 
 The C furnace, 80 feet high, 20 feet diameter in the 
 boshes, and 11 feet in the hearth, with eight 6-inch 
 twyers, with blast at 9 Ibs. pressure, heated at 600 de- 
 grees by three Cowper stoves 60 feet high and 20 feet 
 diameter, averaged 1,070 tons per week for several 
 weeks, with a maximum of 1,276 tons. 
 
 The No. 1 Isabella furnace, in the same district, made 
 4,850 tons in four weeks, an average of 173 tons per 
 
256 METALLURGY OF 
 
 day, with a coke consumption of 22 cwt. per ton in 
 50 per cent. ores. This furnace, 75 feet by 20 feet, is 
 driven with extremely hot blast, estimated at 750 to 
 800, having three Whitwell stoves, each 75 feet high 
 and 21 feet in diameter. 
 
 These large makes, which have since been increased 
 to 2,100 tons per week, and 237 to 419 tons per day 
 (page 518) are, to a great extent, due to the high blast 
 pressure used, about 8 Ibs. to the square inch. The 
 advantage realised by such very rapid working is 
 found in the more perfect utilisation of the capital 
 invested in fixed plant, as the consumption of fuel is 
 but little diminished as compared with furnaces 
 working on similar ores at a slower rate of speed. 
 
 The highest make of American anthracite furnaces 
 now ranges from 350 to 480 tons per week in furnaces 
 similar in dimensions and with about the same pressure 
 of blast as those smelting with coke. The consump- 
 tion of anthracite is about 25 cwts. per ton of pig metal 
 made. 
 
 The charcoal furnaces of Lake Superior and Missouri 
 have also been largely increased in producing power of 
 late years ; the standard sizes of stacks are from 40 to 
 50 feet, and the diameter in the boshes from 9 to 12 
 feet, and the highest recorded weekly make from 120 
 to 180 tons in the smaller and 300 to 350 tons in the 
 larger sizes. One furnace of 55 feet by 11 feet made 
 62 tons in one day, and 389 tons in one week a yield 
 comparable to that of a large coke furnace. The 
 consumption of charcoal is from 86 to 100 bushels, 
 or by weight from 1,700 Ibs. to 2,600 Ibs. per ton of 
 pig iron made. The metal made is mostly dark grey 
 Bessemer, or more particularly " car- wheel," or close 
 grey iron, suitable for chill- casting, which is used 
 
CAPACITY AND PRODUCTION OF BLAST FURNACES. 257 
 
 in the manufacture of railway wheels with chilled 
 treads. 
 
 The ahove information is mostly derived from Mr. 
 Swank's Report to the United States Census Commis- 
 sioner, and refers to the year 1880. 
 
 The total production of pig iron in the world for the 
 year 1888 was probably about 22,000,000 tons, the 
 principal contributions being as follow : 
 
 
 United Kingdom, 1888 
 
 United States 
 
 Germany 
 
 France 
 
 Belgium ,, 
 
 Austria-Hungary ,, 
 Sweden, 1887 . 
 Eussia, 1885 . 
 
 7,898,634 
 
 6,489,738 
 
 4,190,286 
 
 1,483,724 
 
 813,752 
 
 749,420 
 
 452,320 
 
 519,086 
 
 In the United Kingdom the produce by districts 
 was in 1888 : 
 
 Districts. 
 
 Cleveland . 
 
 West Cumberland 
 
 Lancashire . 
 
 Scotland . 
 
 South Wales ... 
 
 South Staffordshire 
 
 Derbyshire . , s . 
 
 South and West Yorkshire 
 
 North Staffordshire . 
 
 Northants, Leicester, &Notts. 
 
 Lincolnshire 
 
 Shropshire . 
 
 Gloucester, Wilts, &c. 
 
 North Wales 
 
 Furnaces. 
 
 Total. 
 
 Weekly. 
 
 No. 
 
 Tons. 
 
 Tons. 
 
 97 
 
 2,614,983 
 
 517 
 
 ) 57 ( 
 
 812,503 ) 
 
 536 
 
 j 1 
 
 771,892 ( 
 
 
 84 
 
 1,027,774 
 
 234 
 
 40 
 
 883,506 
 
 427 
 
 33 
 
 339,615 
 
 198 
 
 26 
 
 307,564 
 
 227 
 
 18 
 
 167,435 
 
 178 
 
 21 
 
 274,095 
 
 260 
 
 19 
 
 328,511 
 
 348 
 
 14 
 
 249,955 
 
 343 
 
 7 
 
 61,005 
 
 174 
 
 2 
 
 32,500 
 
 312 
 
 4 
 
 27,296 
 
 161 
 
 362 
 
 7,898,634 
 
 362 
 
258 METALLURGY OF ISO!*. 
 
 CHAPTER, X. 
 
 OF THE CONSUMPTION OF FUEL AND DISTRIBUTION l>F 
 HEAT IN THE BLAST FURNACE. 
 
 THE theoretical distribution of the heat given out by 
 the fuel in the blast furnace is found by comparing the 
 sensible temperature and weight of the matters dis- 
 charged, multiplied by their specific calorific capaci- 
 ties, with the heat produced by the combustion of the 
 fuel and from other sources, according to the known 
 laws of heat. The following example of a calculation 
 of this kind, made on a French furnace, and exhibiting 
 the results in the form of a debtor and creditor account, 
 is taken from an excellent treatise by De Yathaire, 
 recently published ("Etudes sur les Hauts Fourneaux," 
 chap. vi. 72). 
 
 I. Calculation of the Quantity of Heat absorbed in the 
 different Operations of the Blast Furnace. 
 
 The carbon burnt in the furnace is employed for three 
 different purposes. These are : 
 
 1. Heating of fixed and volatile matters. 
 
 2. Reduction of metallic oxides. 
 
 3. Restitution of heat absorbed during the re- 
 duction. 
 
 Let us select as an example a furnace working upon 
 grey iron (No. 3), whose charges y^'eld 40 per cent, of 
 pig iron, with a consumption of coke 14 per cent, of 
 ash, at the rate of 1,350 kilogrs. per ton (1,000 kilogrs.) 
 of pig iron ; the blast being heated to 300. 
 
 The mean composition of the charge, includin g the 
 ash of the fuel, is as follows : 
 
CONSUMPTION OF FUEL AND DISTRIBUTION OF HEAT. 259 
 
 Peroxide of iron 1,344 equal to 950 iron, or 1,000 cast iron. 
 
 Silica . . 256 \ 
 
 Lime . . 266 649 of slag. 
 
 Alumina . . 127 ) 
 
 Carbonic acid . 257 
 
 Water . . 250 
 
 2,500 kilogrs. weight of charge per ton of 
 metal. 
 
 Quantity of Seat carried out of the Furnace by the 
 liquid Products. The number of units of heat con- 
 tained in the products of fusion was found, by the 
 calorimetric method of melting ice, to be 
 
 330 per kilogr. of grey cast iron, and 
 550 slag. 
 
 The total quantity absorbed, therefore, per 1,000 kilogrs. 
 of metal and 643 kilogrs. of slag, is 
 
 1,000 x 330 330,000 units of heat. 
 649 X 550 r= 354,750 
 
 Making together 684,750 
 
 ,, 
 
 Quantity of Heat carried off by the Waste Gases. 
 Out of the total amount of 1,350 kilogrs. of coke, 50 
 are taken up by the iron, and the remaining 1,300 
 (representing 1,118 of pure carbon) is volatilised, and 
 passes out at the throat. To this must be added 70 '1 
 kilogrs. derived from the carbonic acid of the flux, 
 making a total of 1,188 kilogrs. of carbon volatilised 
 per ton of pig iron. 
 
 The composition of the waste gases by weight was 
 found to be as follows : 
 
260 METALLURGY OP IRON. 
 
 Carbonic acid 12 '80 containing 3*491 carbon. 
 
 Carbonic oxide 2/r53 ,, 12*215 ,, 
 Hydrogen . 0*07 
 
 Nitrogen . 61-60 15'706 ,, 
 
 100-00 
 
 The amount of carbon in the gases being 15-707 per 
 cent., the above quantity of 1,188 kilogrs. represents a 
 total of 7,556 kilogrs., which, being discharged at a 
 mean temperature of 200, carry with them the follow- 
 ing amounts of heat. This temperature is considerably 
 lower than that usually observed in English close- 
 topped furnaces. At Clarence, in Durham, Bell found 
 it to be between 500 and 600. 
 
 
 
 
 Weight. 
 
 Specific 
 heat. 
 
 Sensible 
 heat. 
 
 Total units 
 of heat. 
 
 Carbonic 
 
 acid , 
 
 12-80 
 
 X 
 
 0*221 
 
 X 
 
 200 
 
 X 
 
 7566 
 
 100 
 
 42 
 
 810 
 
 Carbonic 
 
 oxide 
 
 25-53 
 
 X 
 
 0-288 
 
 X 
 
 do. 
 
 X 
 
 do. = 
 
 111 
 
 270 
 
 Hydrogen 
 
 07 
 
 X 
 
 0-903 
 
 X 
 
 do. 
 
 X 
 
 do. = 
 
 
 958 
 
 Nitrogen 
 
 
 
 . 
 
 61-60 
 
 X 
 
 0*275 
 
 X 
 
 do. 
 
 X 
 
 do. = 
 
 256 
 
 370 
 
 Water . 
 
 
 250 
 
 kilogrs. 
 
 X 
 
 1-00 
 
 X 
 
 750 
 
 
 = 
 
 187 
 
 500 
 
 598-908 
 
 The quantity 750 in the last line is made up of the sen- 
 sible heat, 200 plus 550, rendered latent by conversion 
 of the water into steam. 
 
 Quantity of Heat absorbed in the Reduction of Oxides 
 of Iron. The amount of carbon required for the reduc- 
 tion of an iron ore is proportional to the number of 
 equivalents of oxygen contained, or taking into account 
 the difference of atomic weights, is equal to three- 
 quarters of the total weight of oxygen, the equivalents 
 of carbon and oxygen being to each other as 6 to 8 
 Therefore 
 

 CONSUMPTION OF 1'UEL AND DISTRIBUTION OF HEAT. 261 
 
 Protoxide of iron cntg. 77'78 iron and 22*22 oxygen requires 214-2 carbon 
 Magnetic oxide 72-41 27'59 285'6 
 Peroxide. . 70-00 30-00 321-75 
 
 per ton of iron reduced. 
 
 The reduction of the oxide in the furnace is entirely 
 performed by carbonic oxide ; but as the carbonic acid 
 so produced is, by the secondary action of ignited car- 
 bon, immediately re-converted into carbonic oxide, the 
 result is much the same as if it had been effected 
 directly by solid carbon, as it is only near the top of 
 the furnace, where the temperature is comparatively 
 low and the current rapid, that any carbonic acid can 
 exist as such. 
 
 The production of carbonic oxide by the action of 
 carbon upon oxide of iron is attended with a consider- 
 able absorption of heat. Iron, when burnt in oxygen, 
 evolves 6,216 units of heat for each litre of oxygen 
 consumed (1*436 grammes). The inverse phenomenon of 
 reduction, therefore, renders the same amount of heat 
 latent. But 1 litre of oxygen (1-436 grs.), combining 
 with 1 litre of carbon vapour (1-677 grs.) to form two 
 litres of carbonic oxide, only gives out 1,598 units of 
 heat, which, deducted from the 6,216 rendered latent, 
 leaves 4,618 as representing the cooling effect produced 
 for each litre of oxygen displaced from the iron, and 
 converted into carbonic oxide by a consumption of 
 1-077 grs. of carbon. 
 
 The consumption of carbon per ton of iron reduced, 
 and the heat absorbed, is therefore with 
 
 Kilogrs, 
 
 Peroxide of iron . 321-75 of carbon and 1,368,550 units of heat. 
 Magnetic oxide . 285-6 1,270,227 
 Protoxide of iron . 214-2 870,704 
 
 In order to simplify the calculation, the amount of 
 
262 METALLURGY OF IRON. 
 
 heat given out on combustion by the carbon employed 
 in reduction will be for the moment neglected, and 
 only the absorption of heat by the separation of the 
 iron and oxygen brought into account. This is for the 
 different oxides as follows : 
 
 Oxides. Kilogrs. Units. Kilogrs. Units. Kilogrs. Units. 
 
 Fe 2 O 3 1,000 1,298,610 1,429 1,855,700 1,341 1,744,358 
 
 Fe 3 4 1,194,300 1,381 1,649,300 1,282 1,550,342 
 
 FeO 961,840 1,285 1,236,000 1,208 1,161,840 
 
 The third column in the above table shows the quan- 
 tity of heat absorbed in the reduction of a ton of each 
 oxide; the fifth, the amount corresponding to the 
 quantities of each oxide required to make a ton of iron ; 
 in the seventh, a similar series of quantities calculated 
 to the ton of pig iron, supposing it contains 94 per cent, 
 of iron and 6 of foreign matters. 
 
 Seat absorbed by the Reduction of Vapour of Water. 
 The hydrogen contained in the gases of the furnace 
 is derived from the decomposition of steam introduced 
 with the blast. The quantity, *07 per cent, corresponds to 
 47,666 kilogrs. of steam per ton of metal produced, or 
 00786 of the weight of the air injected, a result corre- 
 sponding fairly with the hygrometrical condition of the 
 atmosphere at the time. The amount of heat absorbed 
 by the separation of 4-596 kilogrs. of hydrogen per ton 
 of metal is 
 
 4-596 x 34,742 = 159,681 units of heat: 
 
 34,742 being the calorific power of hydrogen burning 
 to water. 
 
 II. Calculation of Heat developed in the Furnace. This 
 is derived from two principal sources, namely, 
 
 1. Heat produced by the combustion of fuel ; and, 
 
 2. Heat brought into the furnace by the hot blast. 
 
CONSUMPTION OP FUEL AND DISTRIBUTION OF HEAT. 263 
 
 The heat produced by the combustion of 1,118 kilogrs. 
 of carbon is made up of two quantities, part being 
 derived from the formation of carbonic acid, while the 
 remainder results from the imperfect combustion of the 
 larger portion of the fuel to carbonic oxide. 
 
 In addition to the above quantity of 1,118 kilogrs., 
 70 kilogrs. of carbon contained in the gases are derived 
 from the carbonates of the charge, making a total of 
 1,188 kilogrs., distributed as follows in the gases : 
 
 As carbonic acid 3*491 per cent, or in 1,188 kilogrs. 264 kilogrs. carbon. 
 carbonic-oxide 12-216 924 
 
 15,707 1,188 
 
 From this amount, however, must be deducted the 70 
 kilogrs. contained in the carbonic acid of the carbonates 
 which has been volatilised as such, and is not derived 
 from combustion of carbon in the furnace. The total 
 amount disposable for heating purposes therefore be- 
 comes 
 
 194 kilogrs. burnt to carbonic acid. 
 924 carbonic oxide. 
 
 Multiplying these by their respective calorific powers, 
 we obtain 
 
 194 x 7,170 = 1,390,980 
 924 X 1,386 = 1,280,664 
 
 2,671,644 units of heat 
 
 as the total amount of heat given out by the fuel 
 under the conditions of the experiment. 
 
 Heat introduced by the Blast. The quantity of ail 
 blown into the furnace is to be calculated from the pro- 
 portion of nitrogen found in the waste gases. 
 
 The amount of nitrogen in the gases is found to be 
 
 \ . Lr 
 
264 METALLURGY OF IRON. 
 
 61-6 per cent., air containing 76'9 per cent. The 
 amount corresponding to 7,556 kilogrs. of gases evolved 
 in the production of a ton of metal is therefore 
 
 J ^JQQ = 6060-6 kilogrs. of air. " 
 
 Supposing this to be heated to the temperature of 300, 
 the extra amount of heat from this source, the calorific 
 capacity of air bein<* 0*2669, is 
 
 6060-6 X 0-2669 x 300 = 485,272 units of heat. 
 
 The small amount of hydrogen contained in the gases 
 is derived from the decomposition of steam contained 
 in the air by ignited carbon. As the amount of heat 
 absorbed in this decomposition has been deducted, the 
 quantity brought in by the heated water vapour must 
 be taken into account as follows : 
 
 5*2962 kilogrs. of hydrogen contained in the gases corre- 
 spond to 47,666 kilogrs. of water, containing 300 of sensible 
 and 550 of latent heat ; or, in all, 
 
 47,666 x (300 + 550) = 41,506 units of heat; 
 which, when added to 485,272 ,, ,, 
 
 gives -d total of 526,778 
 
 as the contribution of the hot blast to the heat of the 
 furnace ; 
 
 or about 20 per cent, of the whole amount of heat ex- 
 pended, a theoretical determination which fairly corre- 
 sponds with the saving of 20 to 30 per cent, of fuel, 
 obtained in practice by the use of hot blast. 
 
 On comparing the two sides of the account, we obtain 
 the following balance sheet of heat developed and ex- 
 pended per ton of metal. 
 
CONSUMPTION OF FUEL AND DISTRIBUTION OF HEAT. 265 
 
 CR. CAUSES OP ABSORPTION OF HEAT. 
 
 Units. 
 
 Heat carried out of furnace by 1,000 kilog. of molten metal 330,OOC 
 
 649 ., : , slag. 354,750 
 
 . the waste gases . . . 598,908 
 
 rendered latent-by reduction of 1,343 kilog. of peroxide 
 
 of iron . 1,744,358 
 4,596 hydrogen 159,681 
 
 Total amount of heat expended . . . 3,187,697 
 
 DR. SOURCES OF HEAT. 
 
 Heat given out "by combustion of carbon .... 2,671,644 
 
 introduced by the hot blast air 526,778 
 
 Total amount of heat employed . . . 3,198,422 
 
 leaving a balance of 10,725 units unaccounted for 
 a quantity far within the probable limits of error in the 
 computation. A few minor sources and causes of ab- 
 sorption of heat have been neglected, from the want of 
 numerical data for their calculation. These are : 
 
 1. Heat absorbed by the reduction of silica, the 
 calorific power of silicon being undetermined. If it be 
 the same or nearly that of carbon, the reduction of from 
 15 to 20 kilogrs. of silicon per ton of metal will require 
 from 100,000 to 150,000 units of heat. 
 
 2. Latent heat of volatilisation of carbonic acid upon 
 the decomposition of the carbonates. This is probably 
 trifling in amount, judging from the small quantity of 
 fuel consumed in lime-burning. 
 
 3. The cooling caused by the dilatation of the blast, 
 from the pressure of 9 or 10 centimetres of mercury to 
 that of the atmosphere. 
 
 A source of heat not taken into account is that given 
 out by the combination of silica with earthy bases in 
 the formation of the slag. 
 
 Supposing now the blast to be heated to 600 instead 
 
266 METALLURGY OF IRON. 
 
 of 300, the total available amount of lieat becomes 
 3,725j220 an increase of about 16 per cent, on the 
 former quantity. A saving of from 17 to 18 per cent, 
 of fuel was effected by the introduction of Cowper's 
 stoves, producing a similar increase of temperature. 
 If, therefore, the products of combustion remained un- 
 altered, the saving of fuel would appear to be directly 
 proportional to the extra heat introduced by the blast ; 
 but this is by no means certain, and it is probable that 
 a part of the economy is due to more perfect combus- 
 tion. The heating up the large quantity of inert nitro- 
 gen, which in weight considerably exceeds the whole 
 amount of solid materials, fuel and fluxes taken to- 
 gether, before introducing it into the furnace, must ob- 
 viously prevent a great waste of heat in the hearth ; and 
 this saving would be proportionately greater the less per- 
 fect the combustion and the smaller the amount of heat 
 developed by the fuel, supposing the temperature of the 
 blast to be constant. 
 
 In the particular case before us, it will be seen that 
 only about 17 per cent, of the whole quantity of fuel 
 burnt is converted into carbonic acid, with the product 
 of a maximum of heat, the remaining 83 per cent, 
 giving rise to less than one-half of the total amount 
 evolved. Supposing the combustion to have been com- 
 plete, 8,016,060 units would have been evolved, so that, 
 by the imperfect combustion, two-thirds of the total 
 heating power of the fuel is undeveloped. 
 
 The production of carbonic oxide in considerable 
 Quantity is, however, a necessary condition to the proper 
 working of the furnace ; the entire conversion of the 
 fuel into carbonic acid could not be allowed, even were 
 it possible, as the maintenance of a reducing atmosphere 
 is of primary importance. The utmost that can be done 
 
CONSUMPTION OF FUEL AND DISTRIBUTION OF HEAT. 267 
 
 is to increase the relative amount of carbonic acid by 
 the use of compact fuel in large masses, a fine state of 
 division being favourable to the production of carbonic 
 oxide, on account of the larger surface and increased 
 resistance offered to the passage of the gas. 
 
 The effective heating power of the gases may be 
 computed from the analyses given above. The calorific 
 power of carbonic oxide being 2,478 units, and of 
 hydrogen 34,742 units per kilogramme, the total amount 
 obtainable from the gases evolved, per ton of coke burnt 
 in the furnace, is 3,808,492 units of heat, or as much as 
 would be produced from the combustion of 616 kilogrs. 
 of coke. It therefore appears that 61 per cent, of the 
 fuel charged in the furnace remains available in the 
 gases. 
 
 If now the consumption of coke be 30 tons per day, 
 the gases, if applied to steam boilers, will by their 
 combustion raise steam for an engine of 257 horse 
 power. As, however, not more than 80 horse power is 
 required for working the blast engine, there will evi- 
 dently be a sufficiency remaining for heating the stoves 
 and other accessory operations. 
 
 Composition of the Gases of the Furnace at different 
 Heights. This subject has been investigated at different 
 times by Bunsen, JEbelmen, Scheerer, Playfair, Hinman, 
 Tunner, and others, both in coke, charcoal, and coal- 
 fed furnaces. The results arrived at are generally 
 similar, allowance being made in the first instance for 
 the products of distillation where raw mineral fuel ores 
 or fluxes are used. The ultimate products include the 
 whole of the carbon contained in the fuel, less the 
 amount required for carburising the metal produced, as 
 carbonic oxide and carbonic acid in combination, with 
 the oxygen of the air blown in at the twyers, and that 
 
268 
 
 METALLURGY OF IRON. 
 
 set free by the reduction of the ores, the nitrogen of 
 the air, and small quantities of hydrogen and hydro- 
 carbons, arising from the decomposition of water vapour 
 introduced by the blast. 
 
 ANALYSES OF WASTE GASES FROM THE TOPS OF BLAST 
 FURNACES. 
 
 PERCENTAGE BY VOLUME. 
 
 I. 
 
 II. 
 
 III. 
 
 IV. 
 
 Nitrogen 
 
 55-35 
 
 55-62 
 
 57-79 
 
 57-06 
 
 Carbonic acid 
 
 7-77 
 
 12-59 
 
 12-88 
 
 11-39 
 
 Carbonic oxide 
 
 25-97 
 
 25-24 
 
 23-51 
 
 28-61 
 
 Marsh gas . 
 
 3-75 
 
 
 
 
 
 0-20 
 
 ! defiant gas . 
 Hvdrogen . 
 
 0-43 
 6-73 
 
 6-55 
 
 5-82 
 
 2-74 
 
 
 
 
 
 
 No. I. Alfreton, Derbyshire, charge containing calcined argilla- 
 ceous ore, limestone flux, and raw coal. 
 
 II. Audincourt, France, charge containing brown hematite 
 and forge cinders, limestone flux, wood, and charcoal. 
 
 HI. Clerval, France, charge containing brown hematite, lime- 
 stone, and charcoal. 
 
 IV. Seraing, Belgium, charge containing brown hematite, mill 
 cinders, limestone, and coke. 
 
 It will be seen that the principal component of these 
 gases is nitrogen, which is brought in by the blast, and 
 passes through the column of materials without taking 
 part in the chemical changes involved in the reduction 
 of the ore and the combustion of the fuel. The propor- 
 tion is, however, considerably less than in atmospheric 
 air, and as practically none is absorbed, it follows that 
 the considerable increase observed in the amount of 
 oxygen from 12 to 18 per cent, in volume must be 
 derived from the solid materials of the charge. The 
 principal source of this increase is to be found in 
 the decomposition of the oxides of iron in the ore, 
 while a further but much smaller quantity may be 
 derived from the reduction of silica to silicon in hot 
 blast furnaces working on quartzose ores. The pro- 
 
CONSUMPTION OF FUEL AND DISTRIBUTION OF HEAT. 269 
 
 portion of carbonic acid to carbonic oxide diminishes 
 progressively in the gases taken at lower levels, until, 
 in the upper part of the hearth, they are found to 
 consist almost entirely of nitrogen and carbonic 
 oxide. 
 
 According to Tunner, the temperature prevailing in 
 the Styrian furnaces at a point about 3 inches above 
 the twyer level was only 1,450 when making white 
 iron, and 1,750 with grey iron. At the twyers 
 wrought iron melted easily, but not platinum, so 
 that the temperature was assumed as being higher 
 than 1,900, and less than 2,500, or about 2,200. 
 
 The furnace at Eisenerz, upon which these experi- 
 ments were made, the zone of maximum temperature 
 was approximately spheroidal, extending inwards and 
 upwards for about 6 or 7 inches in front of each twyer. 
 It is only within these small spaces that carbonic acid 
 is produced by the complete combustion of the fuel. 
 The amount of carbonic oxide evolved by combustion 
 is greatest with light, easily combustible fuel, such as 
 soft-wood charcoal, and a low temperature and pressure 
 of blast. In the same way the transformation of car- 
 bonic acid into carbonic oxide is more readily effected 
 under similar conditions than with harder fuel, such as 
 coke or anthracite. In charcoal furnaces, therefore, 
 carbonic oxide prevails even at the lowest level, while 
 at a very small height above the twyer carbonic acid 
 is almost entirely absent. Higher up the quantity of 
 the latter gas increases, because in the less highly 
 heated parts of the furnace the oxidation of carbonic 
 oxide by the oxygen of the ore goes on more energeti- 
 cally than the converse reduction of carbonic acid to 
 carbonic oxide by carbon. The temperature at which 
 the reduction of the ore commences is, in the case of 
 
270 METALLURGY OF IRON. 
 
 spathic ores, stated to be from 600 to 700. Reduction 
 and carburisation of the metal are more easily effected, 
 and with a less consumption of fuel, when charcoal is 
 used than is the case with coke, as, although with the 
 latter a more intense heat may be obtained in the lower 
 part of the furnace, the production of reducing gases 
 will be diminished ; for the more compact the fuel, and 
 the denser and hotter the blast, the greater will be the 
 amount of carbonic acid produced at the twyers, and 
 consequently the higher the temperature in the hearth. 
 But as the carbonic acid so produced is less easily con- 
 verted into carbonic oxide by coke than by charcoal, 
 there is likely to be a smaller production of reducing 
 
 The manufacture of pig iron, therefore, is attended 
 with a larger expenditure of fuel when coke is used 
 than is the case with charcoal, but when only heat is 
 involved, as in remelting pig iron for founding, the 
 same weight of iron can be melted with a smaller 
 weight of coke than of charcoal. 
 
 In furnaces worked with raw coal, the gases, in ad- 
 dition to the products of combustion, contain small 
 quantities of condensible vapours, especially tarry 
 matters and ammonia, which it has been proposed to 
 collect and utilise in a similar manner to the waste 
 products of gas works. Bunsen and Playfair suggested 
 that the ammonia might be collected as sal-ammoniac 
 by passing the gases through a chamber containing 
 hydrochloric acid. More recently D. Price has proposed 
 the injection of finely- divided water into the main gas 
 conduit, as well as the use of hydraulic mains, such as 
 are employed in gas works for the same purpose. 
 
 The gases of blast furnaces usually carry over a con- 
 siderable quantity of finely-divided solid matter in the 
 
CONSUMPTION OF FUEL AND DISTRIBUTION OF ITEAT. 271 
 
 form of dust, which deposits in the throat flues and gas 
 culverts, and requires to be removed from time to time. 
 The following is the composition of the dust from 
 two different localities : 
 
 Dowlais, South Clarence, Clev 
 
 Wales (Kiley). land (BeU). 
 
 Silica 
 
 30-33 
 
 . 34-82 
 
 Alumina . 
 
 8-43 
 
 . 16-00 
 
 Peroxide of iron . 
 
 47-05 
 
 . . . 8-20 
 
 Peroxide of manganese 
 
 1-77 
 
 
 
 Lime .... 
 
 2-30 
 
 . 12-15 
 
 Magnesia . 
 
 1-13 
 
 . 0-57 
 
 Protoxide of zinc 
 
 
 
 . 4-60 
 
 Potash 
 
 1-80 
 
 . 0-40 
 
 Soda. -v ;;; ^I . 
 
 0-36 
 
 . 6-85 
 
 Water . ^ 3 . 
 
 0-93 
 
 . 5-60 
 
 Sulphate of lime . 
 
 4-42 
 
 Sulphuric acid 8-80 
 
 Phosphate of lime 
 
 0-75 
 
 Chlorine 1-56 
 
 99-27 99-55 
 
 At the Concordia furnace, nearAix-la-Chapelle, where 
 brown iron ores containing a considerable quantity of 
 oxide of zinc are smelted, the gases are simply washed 
 by passing them through a pipe of large section, kept 
 about half filled with water, by which means a portion 
 of the zinc fume is deposited; sufficient is, however, 
 kept in suspension to render it necessary to clear out 
 all the flues at very short intervals. When the main 
 gas pipe at the throat is obstructed, the furnace is 
 allowed to go down until the top of the column of 
 materials is about 9 feet below the charging plate. The 
 surface is then cooled with water and covered with iron 
 plates, forming a platform for the workmen who are 
 employed in clearing out the deposit. The oxide of zinc 
 recovered is sold to the neighbouring zinc works. 
 
272 METALLURGY 3F IRON. 
 
 The brown iron ores of Upper Silesia contain, in 
 addition to some zinc, from 0'3 to 2-5 per cent, of lead, 
 which is reduced with the iron in the smelting furnace, 
 and filtering through the joints of the hearth bottom, col- 
 lects in the cross-drying flues below. These are kept hot, 
 so that the lead may remain fluid, and when a sufficient 
 quantity has accumulated it is ladled out a'nd cast into 
 pigs. From 10 to 25 tons of lead is thus obtained 
 from a single furnace monthly, and in 1880 the 
 amount returned from six furnaces was 2, 60 6 tons. The 
 lead contains about 16 ounces of silver per ton. 
 
 Blast-furnace gas has its heating power greatly in- 
 creased when freed from dust ; the practice of washing 
 it by passing it through a cylinder or trough partly 
 filled with water before distributing it to the stoves 
 and boilers/ is now becoming general. 
 
 CHAPTER XI. 
 
 VARIETIES AND COMPOSITION OF PIG IRON. 
 
 THE produce of the blast furnace is divisible into seve- 
 ral different qualities, which, for practical purposes, are 
 determined by the appearances presented by a freshly- 
 fractured surface, a certain number of pigs taken from 
 each cast being broken for the purpose. The numerous 
 gradations in the scale are mainly dependent upon colour 
 or degree of greyness, texture or size, of the crystalline 
 plates, and their uniformity and lustre. The largest- 
 grained brilliant and graphitic dark grey metal is 
 known as No. 1 pig, while the smaller- grained va- 
 rieties with diminishing lustre and colour are dis- 
 tinguished by the higher numbers -as far as No. 4. 
 
VARIETIES AND COMPOSITION OF PIG IRON. 273 
 
 Beyond this point, when the metal ceases to be grey, 
 the numerical scale is not used, the remaining quali- 
 ties being known as mottled, with a further division in 
 some instances into weak and strong mottled, and 
 white, the last being the lowest. This classification is 
 subjected to slight variations in different districts, as in 
 the following examples of scales used in differents parts 
 of England : 
 
 Cleveland .... Nos. 1.2.3.4.4 Forge. Mottled. White. 
 Lancashire hematite 1 . 2 . 3 . 4 . V. Mottled. White. 
 
 The grey numbers as far as No. 3 are also called 
 foundry or melting pigs, the lower qualities, which are 
 only adapted for conversion into malleable iron, coming 
 into the class of forge pigs. In Lancashire and Cum- 
 berland two extra classes are made, known as Bessemer 
 iron Nos. 1 and 2. These command higher prices than 
 the same numbers in the ordinary scale. 
 
 The relative greyness or whiteness of pig iron fur- 
 nishes no real standard of quality as compared with 
 the produce of other districts, but is rather an indica- 
 tion of the working conditions of the furnace. Other 
 things being equal, white cast iron can be more readily 
 and cheaply produced than grey, as the same amount 
 of fuel is made to carry a larger burden of ore, and the 
 charges are driven more rapidly. As, however, it can 
 only be used for forge purposes, while the more expen- 
 sive grey metal is available for making either castings 
 or malleable iron, it is usually sought to diminish its 
 production as much as possible, except in special cases, 
 \vhere quantity of make or an extreme economy of 
 fuel is desired. 
 
 White cast iron melts at a lower temperature than 
 grey, but becomes less perfectly fluid : in cooling it passes 
 through the pasty or semi-fluid condition, and contracts 
 
 N3 
 
274 METALLURGY OF IRON. 
 
 very considerably on solidification. Grey cast iron, on 
 the other hand, expands in becoming solid, so as to be 
 capable of filling up the smallest cavities and depres- 
 sions of a mould. When both kinds of metal are con- 
 tained in the hearth of a blast furnace at the same 
 time, the whitest being the heaviest, goes to the 
 bottom, and will be found in the first pigs obtained at 
 the next cast. The method of flowing is also indica- 
 tive of the quality of the molten metals to an expe- 
 rienced eye. White iron flows in a sluggish stream, 
 throwing out brilliant sparks, while the grey foundry 
 qualities run perfectly fluid and without sparks. 
 
 In Sweden, and other countries where the practice 
 of casting in metal moulds is adopted, the fractured 
 surface of the metal, even when perfectly grey, is 
 whitened by the chill to a considerable depth. Another 
 class of metal often obtained under similar circum- 
 stances consists of about equal parts of white columnar 
 and fine dark grey iron in alternating stripes, or the 
 latter may be interspersed in ragged patches, stars, or 
 spots through a white ground. These varieties are in 
 great request for conversion into malleable iron, as 
 they approximate in character to the mixtures of grey 
 pig iron with refined metal that are found to be most 
 advantageous for such purposes. The so-called steel 
 iron or white columnar pig of Siegen, and the flowery 
 pig iron of Styria (blumige floss), are of this character. 
 Common white iron, made with a heavy burden of 
 cinders, is dull in colour, and presents a rough, honey- 
 combed appearance on the upper surface of the pig ; 
 it usually contains a considerable amount of phos- 
 phorus and sulphur, and though very hard ; may be 
 easily broken. 
 
 In the United States, the white pig iron produced in 
 New Jersey from the residues obtained in the treatment 
 
VARIETIES AND COMPOSITION OF PIG IRON. 
 
 275 
 
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 dahl, Siearen. Jordan. 
 
 Spiegeleisen ; No. IX. grey Bessemer pig, from similar ores, Towlaw, "Weardale. Riley. 
 Grey foundry iron, from red hematite, the former from "Whitehavcn, the latter from Cleator, in Cumber- 
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276 
 
 METALLURGY OF IRON. 
 
 
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\ 7 ARIETIES AND COMPOSITION OF PIG IKON. Tl 
 
 of franklinite after the oxide of zinc lias been removed 
 enjoys a very high reputation for use in the manufac- 
 ture of chilled articles, especially crushing and forge 
 rolls and stamp heads. In foundries where the re- 
 melting is performed in reverberatory furnaces, dark grey 
 iron can be used to advantage, and the quality of the 
 metal may be greatly improved by the addition of a 
 proportion of malleable scrap iron. 
 
 The following are the appearances to be noted on the 
 fractures of different classes of foundry iron according 
 to Guettier : 
 
 A moderately large grain of slight lustre, mottled 
 with fine patches having a tendency to whiteness, indi- 
 cates the highest degree of resistance. 
 
 A smaller grain, but similarly dull, with a mottled 
 grey base, marks the quality of metal best suited to 
 resist tractive strains. 
 
 A somewhat fibrous grain, terminating in fine jagged 
 pyramidal points on the fractured surface, with a close 
 regular grey base, is a mark of great transverse strength 
 
 A fine-grained grey metal, bordering upon mottled, 
 when the fracture is small-grained and even, and not 
 in flat broad plates, is the best for resisting compression. 
 
 The varieties presenting the least resistance are 
 those that are full of graphite of a blackish-grey colour 
 and large brilliant grain, or of an irregular grain upon 
 a shining base, and the mottled white kinds in which 
 there is no granular structure apparent. 
 
 Guettier found that No. 1 Scotch pig reached its 
 maximum strength after the eighth melting. Fairbairn 
 found that the same point was reached with No. 3 pig 
 (Eglinton) after twelve meltings. 
 
 Those varieties of cast iron that are smelted from 
 spathic ores containing manganese in considerable 
 quantity are also white and intensely hard, the frac- 
 
278 METALLURGY OF IRON. 
 
 t ured surface presenting an aggregate of bright lamel- 
 lar crystals, sometimes nearly an inch across, forming 
 the so-called specular pig (spiegeleisen). Unlike 
 ordinary white iron, it contains a very large amount of 
 carbon, all of which is in chemical combination. The 
 circumstances favouring its production have been 
 noticed at p. 223. Manganese is always present, but 
 the amount may vary very considerably without affect- 
 ing the large lamellar crystalline structure. 
 
 Strength of Cast Iron. The resistance of cast iron to 
 strains applied in different directions is subject to very 
 considerable variation, according to its composition and 
 quality. The softest, or No. 1 pig, is usually deficient 
 in strength as compared with the lower qualities made 
 from the same ores. It is customary in founding, there- 
 fore, to work with two or more different kinds of metal, 
 in order to obtain mixtures combining the qualities of 
 the different components, or sometimes a proportion of 
 malleable scrap or refined iron is added to grey iron for 
 the same purpose. 
 
 Silicon is generally reputed to be a source of weak' 
 ness in cast iron, such as the dark grey No. 1 Scotch 
 pig smelted from blackband ; and it is for this reason, 
 probably, that hot blast metal is of smaller tenacity 
 than that made with cold blast from the same materials. 
 
 The following are the maximum and minimum limits 
 of strength in British pig iron, as deduced from obser- 
 vations made at Woolwich in 1856-59 : 
 
 Minimum. Maximum. 
 
 Specific gravity . . 6'886 . . 7'289 
 
 Per square inch. 
 
 Tensile strength . . 4-85 tons . 14-05 tons 
 
 Transverse . . . 1-37 . 4-47 
 
 Torsional .... 1-74 . 3-44 
 
 Crushing .... 22'54 . 68-42 ,, 
 
MAKING WROUGHT IRON DIRECTLY FROM THE ORE. 279 
 
 The transverse resistance was measured by the force 
 necessary to break a bar of an inch square when loaded 
 at the same distance from the point of support. The 
 torsional strength was measured by applying a twisting 
 strain to a bar reduced to the same ratio at a distance 
 of 8 inches from its bearings. 
 
 The lowest values were obtained with pig iron smelted 
 from sandy brown hematite, and the highest from hema- 
 tite or argillaceous carbonates, either alone or mixed and 
 smelted with cold blast. 
 
 The chemical composition of pig iron is subject to 
 considerable variation, as will be seen by the preceding 
 table, which comprises analyses from the principal 
 British and foreign iron-smelting districts. 
 
 CHAPTER XII. 
 
 METHODS OF MAKING WROUGHT IRON DIRECTLY FROM 
 THE ORE. 
 
 THE chief modern representative of the bloomeries or 
 hearths by which iron was produced from the earliest 
 ages down to the introduction of the blast furnace is 
 the so-called Catalan or Corsican forge, which still sur- 
 vives in the Pyrenees, and a few other isolated localities 
 in the South of Europe. As it is of comparatively small 
 importance in the economy of modern iron-making, a 
 very brief notice will suffice. 
 
 The hearth, or furnace, employed in this process, is 
 represented in longitudinal section in Fig. 22. The 
 bottom of the hearth is of refractory sandstone, and 
 before using, is lined or brasqued with a coating 
 of charcoal dust or breeze. The front wall, or face, 
 a, is curved outwards so as to increase the capacity 
 of the hearth at the top. The opposite side is 
 
280 
 
 METALLURGY OF IRON. 
 
 provided with a twyer made of sheet copper, in- 
 clined at an angle of from 30 to 40 degrees. The 
 tapping hole for removing the slag is placed 
 in one of the side walls, 
 which is also covered with an 
 iron plate, forming a point of 
 support for the tool used in 
 working the contents of the 
 hearth, and removing the 
 spongy mass or ball of iron 
 produced. 
 
 The blast is usually produced 
 either by a trompe, or a wooden 
 engine with a square piston: 
 its pressure never exceeds 1| 
 to If inches of mercury. 
 
 The method of conducting 
 
 Fig. 22. Catalan Finery. 
 
 the operation is as follows : After repairing the 
 lining of the hearth bottom, a pile of ore, usually a rich 
 and easily-reducible brown hematite, occupying from 
 one- third to one-half of the total contents of the 
 hearth, is placed at b, parallel to the curved wall, 
 the remaining portion, to the twyer wall, being filled 
 with charcoal. The whole is then covered with char - 
 coal dust and small ore (greilkide) moistened with water. 
 At first only a gentle blast is used, and as soon as 
 flame appears at the surface, it is damped by a fresh 
 application of greillade in order to prevent too rapid 
 combustion, and the falling in of the heap before the 
 reduction of the oxide of iron to the metallic state 
 is effected. The preliminary stage lasts about two 
 hours, after which the blast is turned full on, and the 
 slags are tapped off. The workman then pushes the 
 heap of ore further into the hearth by means of an 
 
MAKING \VUOUGHT IRON D1HECTLY FROM THE OllE. 281 
 
 iron bar introduced between it and the front wall. 
 The reduction commences at the bottom of the heap 
 with the formation of spongy masses of iron, which, as 
 they appear, are pushed forward by the workman 
 towards the twyer, in order to facilitate the separation 
 of the metal from the slag by the liojiation of the 
 latter. The progress of the work is chiefly guided by 
 the character of the slags, which are very liquid when 
 highly charged with protoxide of iron, and stiff or 
 pasty when deficient in bases. In the latter case the 
 necessary fluidity is imparted by the addition of 
 finely- divided ore in small quantities, which is 
 allowed to dissolve in the slag without being reduced 
 to the metallic state. This is, in fact, one of the essen- 
 tial points of the process, a portion of the ore being 
 intentionally expended in fluxing the silica, in addition 
 to the earthy bases associated with the peroxide of iron, 
 in order to obtain an easily-fusible slag, which in its 
 turn reacts upon the reduced masses of spongy metal, 
 and prevents the assimilation of carbon and the for- 
 mation of cast iron. Perfect liquidity of the slag is 
 also desirable in order to facilitate its removal during 
 the subsequent forging. 
 
 When the whole of the charge has been reduced, the 
 blast is stopped, and the spongy masses in the hearth 
 are worked together into a lump, or ball, which is 
 lifted out and carried to the hammer, where it is forged, 
 or shingled, to a rough bar, or bloom. During the 
 first period of the process, while the ore is being re- 
 duced, the bloom obtained from the preceding charge, 
 after having been cut up into several pieces, is re- 
 heated in the upper part of the hearth, and drawn out 
 into bars under the hammer. 
 
 The iron produced in the Catalan forge is usually 
 
282 METALLURGY OP IRON. 
 
 more or less hard, and steely, though this depends in 
 great part on the manipulation. By increasing the 
 angle of inclination of the twyer, and keeping a large 
 amount of slag in the hearth, the decarburisation of 
 the spongy mass is facilitated, and a softer iron is 
 obtained than is the case when the ore is allowed to 
 be reduced slowly, and to remain in prolonged contact 
 with the fuel; these conditions being favourable for 
 the production of what is known as steely iron, or 
 natural steel. 
 
 The slags produced in this process consist essentially 
 of tribasic protoxide silicates, the principal base being 
 protoxide of iron ; but lime, magnesia, and protoxide of 
 manganese are generally present in greater or less 
 quantity. The silica usually exists in the ore in a free 
 state as quartz. 
 
 Although the presence of several bases is advan- 
 tageous as tending to produce a fluid slag, it is espe- 
 cially necessary that the amount of the earthy bases, 
 lime and magnesia, should be small, as their silicates 
 are too refractory to be properly melted at the tempera- 
 ture obtained in the hearth. The conditions governing 
 the formation of slags in the Catalan forge are therefore 
 exactly the reverse of those sought to be obtained in 
 the blast furnace, where the scorification of protoxide 
 of iron is prevented by the use of a large amount of 
 lime as a flux for the silica in the charge. It will be 
 shown subsequently that the same considerations are 
 involved in all processes for the conversion of cast into 
 malleable iron. Whenever silica or silicon is present, 
 it is always eliminated as a silicate at the expense of a 
 portion of the metal, and, at the same time, the highly 
 basic silicate so formed, when brought into contact with 
 molten cast iron, acte upon the combined carbon of the 
 
MAKING WROUGHT IRON DIRECTLY FROM THE ORE. 283 
 
 latter, with the production of carbonic oxide and 
 metallic iron. It will be remembered that the nearest 
 approach to this reaction observed in the blast furnace 
 is when the cinder is black and scouring, correspond- 
 ing to the production of white iron poor in carbon. 
 
 The weight of ore treated in a hearth of the largest 
 size in one operation lasting six hours is about 9 J cwt., 
 containing 45 to 48 per cent, of iron, the fuel con- 
 sumed about lOf cwt., and the produce of finished bar 
 iron about 3 cwt. The average consumption of mate- 
 rials per 100 Ibs. of bar iron is, of ore 312 Ibs., and 
 charcoal 340 Ibs., or 100 Ibs. of ore in good work should 
 yield 31 Ibs. of bar iron, and 41 Ibs. of slags contain- 
 ing 30 per cent, of iron. Of the total contents of the 
 ore, therefore, 71 per cent, is reduced to the metallic 
 state, while the remaining 29 per cent, is expended in 
 the slag. The ore in question contains about 14 per 
 cent, of silica. 
 
 The dimensions of the hearth vary indifferent districts ; 
 the smallest, or Catalan fire, in use in the central and 
 eastern parts of the Pyrenees, is 20 inches in length 
 and breadth, 16 inches total depth, 9 inches measured 
 from the twyer to the hearth bottom, and takes a charge 
 of 3 to 4 cwt. of ore. The Navarrese hearth, employed 
 in French and Spanish Navarre and Guipuscoa, is 30 
 inches long, 24 inches broad, and 16 inches deep from 
 the twyer to the bottom ; the charge weighs from 5 to 
 6 cwt. The largest, or Biscayan hearth, is 40 inches 
 long, 30 to 32 inches broad, and 24 to 27 inches in total 
 depth, or from 14 to 15 inches below the twyer. The 
 charges are from 7 to 9 cwt., as given above. 
 
 Various processes for the direct production of 
 wrought iron from the ore have been proposed, differ- 
 ing from the Catalan forge, in the use of a closed vessel, 
 
284 METALLURGY OF LRXXN. 
 
 such, as a gas retort or fire-brick chamber, for the 
 reduction, which, is effected at as low a temperature as 
 possible, either by the direct contact of finely-divided 
 carbon, or in a current of reducing gases produced by 
 the passage of air over red-hot coal in a special gas 
 generator. The spongy masses of iron, after removal 
 and cooling under a covering of charcoal, are welded in 
 open hearths or reheating furnaces, with or without pre- 
 viously undergoing a mechanical separation from the 
 earthy matters by crushing and treatment with electro- 
 magnetic apparatus. As these methods are only appli- 
 cable to the treatment of easily-reducible ores, and 
 are essentially slow in work, giving only a small pro- 
 duction from a plant of considerable extent, as compared 
 with the old open fire, they have not as yet been found 
 to possess sufficient advantages to be generally adopted 
 on the large scale. 
 
 At Santa Ana de Bolueta, in Biscay, Gurlt's process 
 of reducing the rich brown hematite of Sommorosteo, 
 containing 68 per cent, of iron, by means of carbonic 
 oxide, has been tried with the following results. The 
 furnace has a shaft like an ordinary blast furnace, 
 communicating with a series of gas generators near 
 the bottom. When three charges were made daily, 
 72 cwt. of ore and 18| cwt. of charcoal yielded 23'8 cwt. 
 of spongy metallic iron, which was removed while still 
 hot in iron barrows, and allowed to cool under a cover- 
 ing of charcoal dust. The subsequent welding of the 
 sponges or balls was effected in an ordinary Catalan fire, 
 the waste being about 50 per cent, by weight, and the 
 consumption of charcoal equal to the weight of the 
 finished bars produced. The total consumption was, 
 therefore, per 100 Ibs. of bars made, 174 Ibs. of charcoal 
 and 285 Ibs. of ore ; the loss of iron, amounting to nearly 
 
MAKING WROUGHT IRON DIRECTLY FROM THE ORE, 285 
 
 one-half, was larger than in the ordinary Catalan pro- 
 cess, but a considerable saving of fuel was effected. 
 
 In India wrought iron is made directly from the ore. 
 either in shallow hearths with an artificial blast, or in 
 furnaces with shafts, which may be worked with a blast, 
 or by a natural draught, the former resembling the 
 Catalan forge, while the latter may be compared to 
 the lump or wolf furnaces which prevailed in Europe 
 before the introduction of the flowing or modern blast 
 furnace. In either case the dimensions are small, as 
 are also the blooms produced, which vary from 20 Ibs. 
 to 2 cwt. In the Burmese furnaces, which depend upon 
 natural draught, the shaft is excavated in the face 
 of a bank exposed to the prevailing wind, from 10 to 
 15 feet high, a number of conical pipes or nozzles 
 being inserted in an opening at the lower part, corre- 
 sponding in position to the tymp in an ordinary blast 
 furnace. This primitive system of construction is 
 said to have been used by the ancient Celtic inhabi- 
 tants of the Rhenish hill countries, heaps of slags 
 being found in Nassau, on the tops of bare swelling 
 downs far away from water- courses, under circum- 
 stances which indicate the probability of their having 
 been produced in furnaces of this class. 
 
 American Bloomary Process. Although the old 
 process of making iron directly from the ore has been 
 completely abandoned in Germany, it is still employed 
 to a very considerable extent in the United States, 
 where it was introduced early in the eighteenth cen- 
 tury ; and has latterly been employed in Canada for 
 the treatment of the black magnetic and titaniferous 
 sands of the Labrador The following description of 
 the process has been given by Dr. Sterry Hunt : 
 
 The hearth or furnace, also known as the bloomary 
 
286 METALLURGY OF IRON. 
 
 fire, Jersey or Champlain forge, varies in length and 
 breadth, in different localities, from 27 by 30 to 28 by 
 32 inches, and the depth from 20 to 25 inches above 
 the twyer, and from 8 to 14 inches below. The sides 
 are made of cast-iron plates, and the bottom usually of 
 beaten earth or cinders ; but in the best- constructed 
 hearths a hollow casting, cooled by water, is preferred. 
 At East Middlebury, in Vermont, the bottom plate is 
 4 inches thick, with a hollow space of 2 inches within 
 it. The side plates, which are lj inches thick, are 
 slightly inclined inwards, and rest on ledges on the 
 bottom plate. A water-box, measuring 12 by 8 inches, 
 is let into the twyer plate ; and the water, after cooling 
 the twyer, passes through the bottom plate. The twyer 
 is placed 12 inches above the bottom, at such an 
 inclination that the blast may strike the middle of the 
 hearth. It is of segmental form, measuring 1 inch in 
 height by f inch wide. In front of the furnace, at a 
 height of 16 inches above the bottom, is placed a flat 
 iron hearth, 18 inches wide. The side plate beneath it 
 is provided with a tap hole, for drawing off the cinders 
 from time to time. The cast-iron plates used in the 
 construction of these furnaces last for two years. 
 
 The blast employed has a pressure of from 1J to If 
 Ibs. to the square inch, and is heated by passing through 
 a stove of the ordinary siphon-pipe pattern, placed in 
 an upper chamber above the furnace, and heated by the 
 waste flame. The temperature at East Middlebury is 
 said to be from 280 to 320. The use of hot blast is 
 attended with a considerable saving, both of time and 
 fuel, 240 bushels of charcoal being sufficient to produce 
 a ton of bloom with hot, while 300 are required w.\th 
 cold blast. The weight of the charcoal may be esvi- 
 mated at from 16 to 18 Ibs. per bushel. 
 
CONVERSION 01- GREY INTO WHITE CAST IRON. 287 
 
 The working of the furnace is conducted in the 
 following manner : The fire having been made up and 
 the furnace heaped with charcoal, the ore, in a coarsely 
 pulverised form, is scattered at short intervals over the 
 top of the burning fuel, and in its passage downwards 
 is reduced to the metallic state, the grains agglome- 
 rating to an irregular mass or loup at the bottom, 
 while the earthy matters form a liquid slag or cinder, 
 which is drawn off from time to time through the 
 openings in the front plate. Fresh ore and coal are 
 continually added, until at the end of two or three 
 hours a sufficiently large loup is formed. This is then 
 lifted before the twyer to get a good welding heat, and 
 shingled to a bloom under the hammer, the reheating 
 of which is usually effected in the same fire. 
 
 In the larger-sized furnaces a loup of 300 Ibs. is 
 produced every three hours, making the produce per 
 day of 24 hours 2,400 Ibs. of blooms ; in some cases it 
 is said 1,500 Ibs., or even more, are produced in 12 
 hours. 
 
 The essential difference between the Catalan and the 
 American forge consists in the method of charging. 
 In the former the greater part of the charge of ore, in 
 comparatively large lumps, is placed at the commence- 
 ment of the operation on the sloping wall of the hearth 
 opposite the twyer, only the small ore or greillade being 
 added subsequently. In the American or German 
 method, on the contrary, the whole of the ore is reduced 
 to a fine state of division, and is added by small por- 
 tions a plan which dispenses with the charging of the 
 furnace after each operation, and permits of a continuous 
 system of working. 
 
 In order further to economise the waste heat, the 
 plan usually adopted in the Franche-Comte* fire, of 
 
288 METALLURGY OF IRON. 
 
 passing the flame and gases from two hearths into a 
 chamber, which serves for the reheating of the blooms 
 when it is required to draw them out into bars, a set of 
 small blast pipes, placed just above the forge, serves to 
 heat a portion of air, which is led into the chamber to 
 burn any carbonic oxide gas that may have escaped. 
 The gases from the reheating chamber are afterwards 
 employed to heat the principal blast of the forge in the 
 usual manner. 
 
 At Ausable, in the State of New York, the ores 
 employed are dressed so as to yield about 50 per cent, 
 of iron two tons being required to make one ton of 
 blooms; while at the New Russia forges, where a 
 nearly pure magnetite is smelted, three tons of dressed 
 ore are stated to yield two tons of blooms. The loss at 
 this rate would not be more than about 5 per cent, on 
 the theoretical contents of the ore a result which could 
 scarcely be obtained by any other method. 
 
 At Moisie, in Quebec, where titaniferous black sand 
 is treated, the results obtained are not so favourable, 
 owing to the more refractory character of the ore. The 
 twyer is laid nearly horizontal, as it was found that the 
 strong inclination used with coarser ores could not be 
 advantageously used with the fine sands. A less dense 
 blast is also used, the average working pressure 
 being about 1 Ib. to the square inch. Each hearth 
 yields eight loups, or about 15 cwt., in the day of 24 
 hours ; the consumption of charcoal being at the rate 
 of 466 bushels to the ton of blooms. This charcoal is 
 chiefly produced from small and light wood, such as 
 spruce, fir, and birch, the weight being only 15 Ibs. to 
 the bushel, about 62J cwts. being consumed to make a 
 ton of iron. 
 
CONVERSION OF GREY INTO WHITE CAST IRON. 289 
 
 This very unfavourable result is due to the imper- 
 fectly cleaned state in which the ore is smelted the 
 quartz, but more especially llie titanic acid, using up a 
 large portion of the protoxide of iron, in order to form 
 a slag. The amount of titanic acid in the slags is in 
 some cases as high as 34 per cent., and the iron from 
 40 to 52 per cent. By the use of magnetic machines 
 for separating the ore before treating it in the furnace, 
 it would be possible to remove the non-magnetic and 
 more highly titaniferous part, which is practically 
 worthless, leaving a comparatively pure magnetite, 
 which could be much more advantageously smelted. 
 
 The iron produced in the bloomary fire* is very free 
 from sulphur and phosphorus, but is of unequal temper, 
 very soft and harder steely portions being often found 
 in the same bloom. It is therefore best adapted for 
 conversion into cast-steel either in the open-hearth 
 furnace or by fusion in crucibles, for which purpose it 
 is mostly used, except a small portion made into 
 agricultural tools and horse- shoe nails. 
 
 CHAPTER XIII. 
 
 REFINING, OR CONVERSION OF GREY INTO WHITE 
 CAST IRON. 
 
 WHEN grey cast iron is melted in an oxidising 
 atmosphere, the silicon in combination is oxidised to 
 silica, and separates as a silicate of protoxide of iron, a 
 portion of the iron being oxidised at the same time. 
 
 * A very detailed description of this now nearly extinct process is 
 given by Egleston. " Trans. Am. Min. Engineers," vol. viii., p, 515. 
 
290 METALLURGY OF IRON. 
 
 If the metal be run into moulds and suddenly cooled, 
 the Y7hole of the carbon enters into combination, with 
 the production of a peculiar silvery- white metal, which 
 is analogous in composition to that smelted from pure 
 ores at a low temperature with a high burden of 
 materials. The same result may be obtained by strip- 
 ping thin plates or discs from the bath of molten 
 metal by throwing water on to its surface, and sub- 
 jecting them to a red heat in contact with air for several 
 hours, a process followed in parts of Germany, and 
 known as roasting (braten). The more usual method, 
 however, consists in melting the metal with coke or 
 charcoal in a small hearth of rectangular section, with 
 one or more inclined twyers, through which cold blast 
 tiir is made to impinge upon the surface of the melted 
 metal. This process is known as refining, and the 
 furnace, or hearth, as the refinery. The object of the 
 operation is to reduce the fluidity of the melted metal, 
 as well as to diminish the amount of silicon, or slag- 
 making material, whereby the subsequent treatment in 
 the puddling furnace is facilitated. The term u running 
 out fire," which applies to the refinery, has reference to 
 the use of a long cast-iron trough, forming a chill-mould 
 for the metal, which is run out of the hearth as soon as 
 the refining has been carried to the proper point. 
 
 The general arrangements of a refinery fire are shown 
 in Figs. 23, 24, which, together with the accompanying 
 description, have been taken from Tomlinson's " Cyclo- 
 paedia." 
 
 The hearth H, Figs. 23, 24, is 2J feet wide, and 3J 
 feet long. It is formed by the junction of four cast- 
 iron troughs, i, through which a stream of cold water 
 is made to circulate, to prevent them from being fused 
 by the heat. The bottom, of the crucible is of grit- 
 stone or argillaceous sand, and is slightly inclined in 
 
CONVERSION OF GREY INTO WHITE CAST IRON. 291 
 
 the direction of the tapping-hole, o. The air, which is 
 usually supplied by the same engine that blows the 
 
 Fig. 23. The refinery. 
 
 blast furnaces, enters the hearth through the six twyers, 
 
 Fig. 24. Plan of refinery. 
 
 t, which are inclined at an angle of from 25 to 30, 
 and so arranged that the blast from each may ,be 
 
 o2 
 
292 MfctALLUfcGY OF IttOtf. 
 
 directed towards the face of the opposite side of the 
 furnace, not in opposition to the opposite twyer. The 
 twyers are furnished with double casings, through 
 which cold water is constantly running. A supply of 
 water is brought by a pipe p into the reseryoirs e, 
 whence it passes to the twyers, through the pipes/, and 
 escapes through the tubes c' into the tanks w, into 
 which the water from the iron troughs flows by the 
 syphon tubes c. A furnace of this kind consumes 
 about 400 cubic feet of air per minute. This is sup- 
 plied by the pipes T, which are furnished with screw- 
 valves at s for regulating the supply. Above the 
 hearth is a chimney 16 to 18 feet high, supported by 
 four cast-iron columns, so as to allow free access to 
 the fire on all sides. The tapping hole o is placed in 
 one of the shorter sides of the hearth, and by it 
 the melted metal and the slag flow out into the 
 mould c, where the metal is cooled by quenching with 
 water. 
 
 In Wales the hearth of the refinery is about 4 feet- 
 square, and from 15 to 18 inches deep, with two or 
 three twyers on either side. In Yorkshire the twyers 
 usually alternate with each other on opposite sides, 
 two being placed on one side and three on the other. 
 The hearth bottom is made of sandstone or fire-brick. 
 Sometimes the metal is run in directly from the blast 
 furnace, but more usually the charge of selected pigs is 
 melted down with coke in the hearth. In the latter 
 case, the metal in the form of pigs and scrap is placed 
 in alternate layers with coke, upon a bed of ignited 
 fuel, at the bottom of the hearth, and the blast is 
 supplied at a pressure of from 1 \ to 2J Ibs., according 
 to the combustibility of the coke. In from two to two 
 and a half hours' time, the charge, weighing two tons, is 
 
CONVERSION OF GREY INTO WHITE CAST IRON. 293 
 
 melted. Fresh fuel is then, added, and the blowing is 
 continued for half an hour, until the metal is sufficiently 
 decarburised. The fluid contents of the hearth, metal 
 and slag, are then tapped off together into shallow 
 cast-iron, troughs placed in front, which are kept cool 
 with water. The usual dimensions of the moulds are 
 about 10 feet long, 3J feet broad, and 6 or 8 inches 
 deep. The separation of the slag is facilitated by 
 throwing water upon the surface. When the metal is 
 run directly from the refinery into the puddling furnace, 
 the slag must first be removed. 
 
 When freshly-fractured fine metal is of a silvery- 
 white colour, the lower part is compact, with a radiated 
 or parallel columnar structure, the top being dull 
 and cellular. The usual thickness of the plate of 
 metal is about 3 inches to a depth of 1 inch or 1| 
 inch. From three to four hours are necessary to work 
 off one charge, according to whether the iron is grey 
 or white, the former taking the longer time. The con- 
 sumption of coke is about 2J cwt. per ton of pig 
 iron operated upon. When taken directly from the 
 blast furnace, 22*3 cwt. of common forge, or 22*1 
 cwt. of good grey cast iron, are required to produce one 
 ton of fine metal. In the melting finery the quanti- 
 ties are about 20 per cent. more. The slag produced 
 amounts to about 3 cwt., and contains from 50 to 60 
 per cent, of iron. 
 
 The loss of weight in refining hot blast pig iron, 
 from its being more highly charged with foreign 
 matters, is greater than is experienced in the treat- 
 ment of that smelted by cold blast. The metal pro- 
 duced from blackband is especially difficult of treat- 
 ment, owing to its comparatively ready fusibility, 
 which renders it necessary to continue the blowing for 
 
294 METALLURGY OF IRON. 
 
 a long time, with a corresponding increase of waste, 
 24 cwt. being required to make a ton of fine metal. 
 The twyers are usually inclined at an angle of 38 , 
 and from 1J to 1} inches in diameter : 94,000 cubic feet 
 of blast are given per ton when the metal is run in 
 from the blast furnace, but when melted in the hearth 
 136,000 feet are required with white, and 153,000 feet 
 with grey cast iron. The weekly production of a 
 refinery is from 150 to 160 tons in the former, and 
 from 80 to 100 tons in the latter case. About 16- 
 horse power is required to furnish the blast. In 
 France and Belgium, the consumption of coke is about 
 30 per cent, by weight of that of the pig iron refined. 
 A hearth with six twyers produces 130 tons, and one 
 with four twyers only 90 tons of fine metal per week. 
 
 The process of refining may be accelerated in the 
 same manner as is usual in all methods of making 
 malleable from cast iron, namely, by the addition of 
 solid oxygen in the form of rich basic silicates of pro- 
 toxide of iron, such as the slags from reheating fur- 
 naces, or forge scale, which consists chiefly of magnetic 
 oxide of iron. By the use of these fluxes the action of 
 the blast is supplemented, and the carbon of the cast 
 iron is employed in the reduction of a portion of the 
 oxides of iron to the metallic state, with a diminution 
 of the loss of iron. The saving is, however, more 
 apparent than real, as the essential point of the pro- 
 cess is the removal of combined silicon, and this can 
 only be effected by its oxidation to silica, with the 
 simultaneous production of tribasic silicate of protoxide 
 of iron ; and whether this be done at the expense of the 
 metal under treatment, or of the iron reduced by the 
 secondary reaction from the rich slags added, is of very 
 little consequence, as the latter owe their origin to 
 
CONVERSION OF GREY INTO WHITE CAST IKON. 29 f 
 
 exactly the same kind of destructive action upon 
 metal previously operated upon. 
 
 Lime may be beneficially employed as a flux for the 
 removal of sulphur, especially that contained in the 
 fuel, but its use is restricted by the fact of its giving 
 a pasty and comparatively infusible slag, except when 
 present in very moderate quantity. Manganese works 
 in a similar manner, but more efficaciously, and, as 
 has been already stated in considering its action in 
 the blast furnace, increases the fluidity of the slag. 
 
 In Silesia, the conversion of grey into white cast 
 iron is performed in the reverberatory furnace, heated by 
 gas instead of solid fuel. The construction is very 
 similar to that of the ordinary founder's reverberatory 
 furnace. The bed is made of sand set in an iron frame 
 with hollow sides, which is kept cool by a current of 
 air passing through it. The fireplace is replaced by a 
 vertical shaft of rectangular section, about 5 feet high, 
 which is filled with coal. Air at a pressure of about 
 4 Ibs. per square inch is admitted through a passage 
 close to the level of the floor, and is distributed to the 
 fuel through a number of small parallel jets attached 
 to a wrought-iron pipe. The gas produced by the 
 imperfect combustion of the coal is burnt at the top of 
 the shaft, which corresponds in position to the fire- 
 bridge of an ordinary furnace, by a fresh supply of 
 air introduced through a long narrow mouth-piece, 
 extending across the entire breadth of the hearth, 
 and inclined at an angle of about 30, so that the 
 Same is urged downwards in a thin sheet upon the 
 surface of the metal. The charge, weighing two tons, 
 takes about three hours to run down, during which 
 time the draught is regulated by the stack alone. A 
 small quantity of limestone is then added, in order 
 
296 METALLURGY OF IRON. 
 
 to convert the infusible dross on the surface of the meta? 
 into slag, after which the blowing proper commences, 
 by means of a further supply of air from two twyers 
 placed on opposite sides of the hearth, which impinge 
 obliquely on the molten metal, producing a movement 
 of rapid rotation. The duration of the operation varies 
 from two and a half to five hours, according to the 
 quality of metal required, the longer time giving a 
 perfectly white iron. The loss is only about 5 per 
 cent., owing to the use of limestone flux. According 
 to Abel, the change is chiefly confined to the elimina- 
 tion of carbon and silicon, as in the common refinery, 
 sulphur and phosphorus, when present in the pig iron, 
 being but slightly affected. The following are the rela- 
 tive proportions of these elements before and after 
 refining : 
 
 Pig iron. Refined iron. 
 
 Silicon . . . 4-66 . . 0'62 
 
 Phosphorus . . 0'56 . . 0'50 
 
 Sulphur . . 0-04 . . 0'03 
 
 The amount of silicon remaining is considerable ; but 
 this is probably due to the use of limestone instead of 
 fluxes containing oxides of iron, the object being 
 merely the production of refined iron for foundry 
 mixtures, and not for conversion into malleable iron. 
 
 In Parry's method of refining, the cast iron operated 
 upon is run directly from the blast furnace into the 
 hearth of a reverberatory furnace, heated by a coal fire 
 in the usual way. The blowing is effected partly by 
 air and partly by a jet of steam, introduced through a 
 twyer inclined at an angle of 45. The weight of the 
 charge is 35 cwt. of pig iron, and about 7 cwt. of 
 forge cinders. A ton of grey iron may be refined by 
 steam in half an hour. The jet is three-eighths of an 
 
CONVERSION OF GREY INTO WHITE CAST IRON. 297 
 
 inch in diameter, with a pressure of from. 30 to 40 Ibs., 
 and superheated to 300 350, by keeping the 
 orifice about 2 or 3 inches above the surface of 
 the iron. Of course, water twyers must be used, as in 
 the case of the hot blast furnace. The consumption of 
 coal is said to be at the rate of 2 cwt. per ton of re- 
 fined metal produced. This is chiefly expended in 
 replacing the heat absorbed by the decomposition of 
 the steam, which produces great local cooling, so that, 
 if the supply be too great, as compared with that of the 
 air blast, the iron may be cooled below its melting 
 point. 
 
 The following analyses of metal and slags, obtained in 
 this process at EbbwVale, in South Wales, are byroad: 
 
 Pig iron used. Refined metal. 
 Carbon, graphitic . 2*40 . . 0*30 
 Silicon . . . 2-68 . . 0'32 
 
 Slag ,,.;: ',..; . 0'68 . . 
 
 Sulphur ;j. , . 0*22 . . 0'18 
 
 Phosphorus . . 0'13 . . 0*09 
 
 Manganese . . 0'36 . .0'24 
 
 Forge cinder added. Cinder rim out. 
 
 Sulphur . . 1-34 . .0-16 
 
 Phosphoric acid . 2 '06 . . 0'13 
 
 The slags obtained are therefore as pure, in respect to 
 sulphur and phosphorus, as the ordinary run of Welsh 
 iron ores. 
 
 The process introduced by Mr. Heaton, of Langley 
 Mill Iron Works, near Nottingham, may be conve- 
 niently noticed at this point, as, though intended for 
 the production of steel, it is essentially a modification 
 of the refinery, with this difference, that nitrate of soda 
 is employed as an oxidising agent, instead of a blast of 
 air. 3 
 
298 METALLURGY OF 1KOJS. 
 
 The converter is a wrought-iron cylindrical cupola 
 lined with refractory material, having a movable bot- 
 tom, which when in use is kept in place by iron clamps. 
 The lower part of the bottom is filled with nitrate 
 of soda, in the proportion of 2 cwt. to the ton of 
 iron treated. Sometimes, but not always, an addition 
 of about 25 Ibs. of siliceous sand is made. This 
 charge is covered over by a closely-fitting per- 
 forated plate of cast iron, in order to prevent it 
 from floating up through the molten metal without 
 decomposition. When the bottom is adjusted, molten cast 
 iron is introduced through the charging-hole at the top. 
 The effect of the nitrate upon the oxidisable matter in 
 the iron is but slight for about five or six minutes, until 
 the covering plate is melted, when a violent ebullition 
 takes place, and a bright yellow flame issues from the 
 top of the chimney for about a minute and a half more, 
 when the action rapidly subsides. The bottom of the 
 converter, with its contents, is then detached, and 
 removed by a truck, placed below it. The product 
 of this operation, which is called crude steel, is not 
 sufficiently fluid to be run out into moulds when only 
 small charges of 12 cwt. or 15 cwt. are operated upon. 
 The contents of the converter are therefore turned out 
 upon the floor, and are then broken up into lumps of 
 convenient size for further treatment. 
 
 This consists of a series of pilings and reheatings in 
 an ordinary balling furnace, after being shingled into 
 blooms or cakes of crude steel, when iron bars or plates 
 are required ; or the cakes may be melted in crucibles 
 in the ordinary way to form crucible cast steel. 
 
 Several investigations of the nature of the changes 
 taking place in this process have been published, the 
 first being that of the late Dr. W. A. Miller, F.E.S., 
 
CONVERSION OF GREY INTO WHITE CAST IRON. 299 
 
 who examined specimens taken at the Langley Mill 
 
 Works in 1868, and has given the following ana- 
 lyses : 
 
 
 A. 
 
 B. 
 
 C. 
 
 Carbon . . 
 
 2-830 
 
 1-800 
 
 0-993 
 
 Silicon, with a little titanium . 
 
 2-950 
 
 0-266 
 
 0-14 
 
 Sulphur .... 
 
 0-113 
 
 0-018 
 
 trace. 
 
 Phosphorus .... 
 
 1-455 
 
 0-298 
 
 0-292 
 
 Arsenic . . 
 
 0-041 
 
 0-039 
 
 0-024 
 
 Manganese . . . 
 
 0-318 
 
 0-090 
 
 0-088 
 
 Calcium .... 
 
 n 
 
 0-319 
 
 0-310 
 
 
 
 0-144 
 
 trace. 
 
 Iron (by difference) . 
 
 92-293 
 
 97-026 
 
 98-144 
 
 100- 100- 100- 
 
 A. cupola pig ; B. crude steel ; C. steel-iron. 
 
 The nature of the above products is not apparent 
 from the analyses, as the terms do not seem to be used 
 in the ordinary sense. Thus, the so-called steel iron 
 contains as much carbon as a very strong steel. The 
 amount of phosphorus retained, though said to be 
 insufficient to injure the quality of the iron, is about 
 four times as much as that in the best Yorkshire iron, 
 or from ten to fifteen times as much as in Swedish 
 Bessemer steel. 
 
 Gruner, who examined Heaton's process for thu 
 purpose of testing its applicability to the pig iron 
 smelted in the Moselle valley, states that the iron and 
 steel produced were capable of resisting a high tensional 
 strain, but that the elongation before fracture was very 
 small, which shows the metal to be hard and deficient 
 in body, the defect being most marked in the hardest 
 steel, the softer steel and homogeneous iron being com- 
 parable to ordinary Bessemer steel, only somewhat 
 harder. 
 
300 METALLURGY OP IRON. 
 
 Grey pig iron, rich in silicon, is less readily purified 
 than white, as the silicon is oxidised before the phos- 
 phorus. Even in the most favourable case, the re- 
 moval of the latter element is very incompletely per- 
 formed, the refined metal retaining about one- third of 
 the quantity contained in the pig-iron. Gruner there- 
 fore suggests, in order to prevent a great waste of 
 nitrate of soda, the propriety of removing the bulk of 
 the silicon and phosphorus by preliminary treatment in 
 an ordinary Welch or reverberatory refinery, the fine 
 metal being then run direct into the Heaton converter 
 for a further purification with the nitrate. It is doubt- 
 ful, however, whether there would be any advantage 
 in adopting such a complicated method of treatment, 
 and the revival of the use of the refinery for ordinary 
 forges would be a decidedly retrograde step. 
 
 The following analyses, illustrating the changes that 
 take place both in the ordinary refinery and in the 
 Heaton process, are by Mr. G. J. Snelus, of Dowlais : 
 
 
 I. 
 
 II. 
 
 ni. 
 
 IV. 
 
 V. 
 
 VI. 
 
 Carbon, graphitic 
 " combined 
 
 0-800 ) 
 1-797 j 
 
 2-428 
 
 2-360 { 
 0-446) 
 
 2-570 
 
 2-061 
 
 1 093 
 
 Silicon 
 
 . 
 
 1-908 
 
 0-128 
 
 2-006 
 
 1-959 
 
 0-014 
 
 trace 
 
 Sulphur 
 
 ''-i. " 
 
 0-553 
 
 0-144 
 
 0-034 
 
 trace 
 
 trace 
 
 trace 
 
 Phosphorus 
 
 jf'- 
 
 0-886 
 
 0-815 
 
 0-446 
 
 0-558 
 
 0-489 
 
 0-344 
 
 Manganese - 
 
 . 
 
 0-050 
 
 trace 
 
 0-648 
 
 0-885 
 
 0-064 
 
 0-072 
 
 I. is an ordinary white forge pig iron ; II. the refined metal made 
 from it ; III. and IV. are two different brands of pig, mixed together 
 to form the charge in the Heaton converter ; V. is hard, and VI. is 
 soft crude metal from the converter. 
 
 It will be seen, by comparison of No. II. with Nos. V. 
 and VI., that the most marked effect of the nitrate is 
 the almost entire removal of the silicon, which is to be 
 attributed to the fluxing effect of the alkaline base. 
 
 Henderson's method for the production of steel and 
 
CONYEKSIOJf OF GREY INTO WHITE CAST IRON. 301 
 
 malleable iron from inferior brands of pig, depends upon 
 the joint use of titanic acid and fluor spar, whereby 
 silicon, sulphur, and phosphorus are said to be wholly, 
 or in part, removed. 
 
 The first operation consists in the production of 
 titaniferous cast iron of the following composition, by 
 fusing 1 ton of Cleveland pig with 7 cwt. of Norwegian 
 titaniferous iron ore : 
 
 Carbon 1-298 
 
 Silicon 1-814 
 
 Titanium 1-255 
 
 Phosphorus . . . .0-460 
 Sulphur . . . . . 0-362 
 
 The metal from the first operation is charged upon a 
 bed of powdered fluor spar, spread uniformly over the 
 bottom of a puddling furnace, and when melted, the 
 fining takes place by the reaction of the fluoride upon 
 the silicon and other foreign matters in the charge, so 
 that the operation is completely performed under the 
 slag, without stirring or manual labour, other than that 
 required for balling up the finished iron. The compo- 
 sition of a sample of malleable iron produced in this 
 way is given as follows : 
 
 Titanium 0-022 
 
 Carbon ; } *' . . . . . trace 
 Silicon v f * . . . , none 
 Phosphorus . . . .0-140 
 Sulphur ..... 0-062 
 
 This is said to be a good malleable iron, although con- 
 taining no carbon, which seems improbable. 
 
 A simpler modification of the process, consists in using 
 the titaniferous ore and fluor spar together in the pud* 
 
302 METALLURGY OF IROS. 
 
 dling furnace at one operation. When melted pig iron 
 is well incorporated with rich iron ore, or scale oxides, 
 in the hearth of a reverberatory furnace, at a heat 
 approximating to the melting point, a violent action 
 is set up, and the bulk of the silicon and phosphorus 
 are oxidised and removed in the slag before the carbon 
 is much affected. This method of purifying common 
 pig iron was described by J. L. Bell in 1877, who found 
 that an exposure of ten minutes was sufficient to reduce 
 the silicon in the metal treated from 1-8 to 0'05 per 
 cent., and the phosphorous from 1/4 to (HO per cent., 
 while the carbon was only changed from 3 '5 to 3*3 per- 
 cent. This process has been adopted on a considerable 
 scale by Krupp of Essen, and is described by Holley 
 as the Washing Process. It is carried out in a Pernot 
 regenerative furnace with a revolving dish hearth 
 (described at page 470), which is lined with lumps 
 of refractory iron ore heated to near the melting 
 point. The fettling ore, which should contain from 
 6 to 15 per cent, of silica, is about 20 per cent, of 
 the charge of metal. When the silica exceeds the 
 latter limit, or the silicon of the metal is more than 
 1 per cent., on as much lime as there is silica in 
 the ore should be added. The metal should, if pos- 
 sible, contain about 1 per cent, of manganese. The 
 charge from 5 to 7 tons, is run into the furnace melted 
 from the cupola, the heat being above puddling, but 
 below steel-melting temperature. The action is very 
 rapid, and the slag as it forms boils and runs over ; the 
 end of the operation, which lasts from five to eight 
 minutes, is marked by a sudden evolution of carbonic 
 oxide. The fined metal is either run into pigs or 
 taken directly to the open-hearth steel furnace. About 
 three-fourths of the total phosphorus is thus eliminated, 
 
PRODUCTION OF WROUGHT IRON IN OPEN FIRES. 303 
 
 CHAPTER XIY. 
 
 PRODUCTION OF WROUGHT IRON IN OPEN FIRES. 
 
 THE numerous processes employed in the production of 
 malleable from cast iron are divisible into two classes, 
 according to the nature of the furnaces employed, 
 namely, open-fire or hearth fineries, where the pig iron 
 is melted and decarburised in a shallow hearth before 
 the blast of an inclined twyer, and reverberatory or 
 puddling fineries, where the same operation is performed 
 on the bed of a reverberatory furnace. The reactions 
 going on during the process are similar in either case. 
 The carbon, if it exist originally as graphite, first 
 passes into the combined state, and is then converted 
 into carbonic oxide either by the oxygen of the blast, 
 directly, or indirectly by the action of protoxide, 
 peroxide, or magnetic oxide of iron dissolved in the 
 slag. These oxidising agents may be derived from the 
 pig iron under treatment, which is always oxidised to a 
 certain extent under the influence of the blast during 
 the melting, or they may be added in the form of red 
 hematite, forge scale, or slags containing protoxide of 
 iron in large quantity, such as are produced towards 
 the end of the finery process itself. When these 
 latter substances are used, it is necessary to bring them 
 into intimute contact with the metal by mixing them 
 well together when the charge is in a semi-fluid con- 
 dition. 
 
 "White cast iron is more suitable for conversion into 
 malleable iron than grey, as it does not, when raised to 
 a high temperature, pass immediately from the solid to 
 the liquid state, but assumes, when near its melting 
 
304 METALLURGY OF IROX. 
 
 point, an intermediate or pasty condition, favourable to 
 the more effectual action of the air or other agents 
 employed in the removal of the combined carbon. 
 Grey metal, on the other hand, though requiring a 
 higher temperature for fusion, becomes very liquid, 
 and in a deep hearth sinks below the level of the blast, 
 and becoming covered with a coating of slag, is com- 
 pletely protected against the action of the air, unless it 
 is brought under the influence of the blast by stirring 
 or lifting with an iron bar, an operation which in- 
 volves great labour, and delays the fining. This gives 
 rise to an increased expenditure of fuel and waste of 
 iron. No sensible amount of decarburisation takes place 
 until the whole of the graphitic carbon has entered 
 into combination with the iron, or what amounts to 
 the same thing, until the metal has passed from the 
 grey to the white state : this conversion is an essential 
 preliminary in all finery processes where the air is 
 introduced above the surface of the melted metal. 
 
 In Bessemer's process, which consists essentially in 
 forcing air through molten pig iron from below, 
 exactly the reverse conditions prevail, grey pig iron 
 being exclusively used on account of its fluidity, and 
 probably from the uncombined carbon being readily 
 consumed, owing to the extremely high temperature 
 at command. As the removal of the carbon is effected 
 by air alone, the plastic quality of white iron is not 
 requisite, and would interfere with the free passage of 
 the blast. This process, although of great importance 
 in steel manufacture, is not directly used in the pro- 
 duction of malleable iron ; it will not, therefore, be 
 necessary to consider it further in this place, it being 
 only mentioned to show the great practical differences 
 in the action of a blast of air upon molten cast iron, 
 
PRODUCTION OF WROUGHT IRON IN OPEN FIRES. 305 
 
 according to whether it be made to act from above or 
 below the metal. 
 
 Grey pig iron is often subjected, as a first step in 
 the process of making malleable iron, to a preliminary 
 oxidising fusion in the refinery or running- out fire, 
 which is a rectangular hearth with one or more 
 strongly-inclined twyers. The molten metal, after a 
 certain amount of blowing, which deprives it of its 
 graphitic carbon and silicon, is converted into fine or 
 refined metal, and may either be run directly into the 
 fine^ furnace or hearth, cast in chilled moulds, or 
 stripped in thin flat discs by throwing water upon its 
 surface when melted. The product is a white brittle 
 metal, resembling the cellular or flowery white pig iron 
 obtained in charcoal furnaces from a heavy burden of 
 rich ores ; it differs from common or white cinder pig 
 iron in being almost free from silicon. 
 
 The application of the terms finery and refinery is 
 somewhat contradictory : the latter, though apparently 
 of larger signification than the former, refers only to 
 a single step in the process of making malleable iron, 
 namely, the conversion of grey into white cast iron. 
 In Germany, this operation is distinguished as whiten- 
 ing (weiss machen), and the finery or conversion 
 proper of' cast into malleable iron as freshening 
 (frischexi). The same term is applied to the reduction 
 of metallic lead from litharge, an operation known in 
 England as reviving. In former times hearth fineries 
 were usually called bloomeries a term having refer- 
 ence to the form of the product, which was called a 
 bloom or lump. The reheating or welding fires were 
 called cha/eries. 
 
 The methods of making malleable iron depending 
 upon the use of open fires or hearth fineries, though of 
 
306 METALLURGY OF IRON. 
 
 great interest from their antiquity and comparative 
 simplicity, are gradually diminishing in importance, 
 owing to the more general use of the reverberatory or 
 puddling process, which can be advantageously em- 
 ployed with fuel and materials of a lower quality, and 
 also requires less skill in manipulation, owing to the 
 more extensive use of machinery in the elaboration of 
 the finished product. 
 
 In a general way, the working of a hearth finery 
 may be described as follows : the charge of pig iron, 
 usually in the form of broad thin slabs, is introduced 
 into a shallow rectangular hearth, whose sides and 
 bottom are formed of cast-iron plates, which are pro- 
 tected against the action of the fire by a lining or 
 brasque of charcoal dust. The fuel employed is char- 
 coal, the fire being urged by a blast of cold, or some- 
 times heated, air, introduced through an inclined twyer 
 placed on one of the sides close to the top of the 
 hearth. The fusion of the metal is allowed to take 
 place very gradually, so that it may be exposed as fully 
 as possible to the oxidising influence of the blast by 
 falling in single drops through the entire height or 
 depth of the hearth. By this means the silicon is 
 converted into silica, and together with any sand 
 adhering to the surface of the pig, combines with 
 protoxide of iron, produced at the same time, forming 
 a fusible silicate of protoxide of iron or slag, which, 
 being specifically lighter than the molten metal, swims 
 above it. As t'he oxidation of the iron continues, the 
 slag becomes more basic by the addition of magnetic 
 exide in indefinite proportions, which, when the whole 
 mass is well liquefied, reacts upon the carbon of the 
 metal, producing malleable iron and carbonic oxide, 
 Owing to the intensely oxidising atmosphere prevail 
 
PRODUCTION OF WROUGHT IRON IN OPEN FIRES. 307 
 
 ing in the hearth, the production of the silicate goes 
 on much more rapidly than its reduction by combined 
 carbon, so that the volume of slag increases to such an 
 extent as to form a coating sufficient to protect the 
 metal from the action of. the blast. It therefore be- 
 comes necessary to break up the iron, that is, to lift 
 the imperfectly- refined masses from the bottom of the 
 hearth to the twyer, in order to subject them afresh to 
 the joint influences of the blast and slag as often as 
 may be necessary, until the carbon is almost entirely 
 removed. 'With the progressive decarburisation, the 
 fusibility of the mass diminishes, and ultimately a 
 spongy, slightly coherent mass or ball of malleable iron 
 is obtained, which, when removed from the hearth, is 
 at a strong white heat, and therefore susceptible of 
 being welded, and is immediately reduced to a rough, 
 prismatic lump, called a bloom, or a slab, by the blows 
 of a heavy hammer moved by steam or water power. 
 The bloom is drawn out into a finished bar undei che 
 same or a lighter hammer, after reheating either on 
 the same hearth during the melting down, of the next 
 charge, or in a fire or furnace of special construction. 
 
 The simple operation sketched out in the preceding 
 paragraph is susceptible of numerous modifications. 
 More than a dozen so-called finery methods have been 
 described by Tunner as in use at the present day : they 
 are for the most part confined to the continent of 
 Europe. As may be imagined, the differences between 
 them are in many cases extremely small, and turn 
 rather upon details of manipulation than actual diversity 
 in principle or construction of apparatus. The most 
 remarkable point in connection with this subject 13 
 the great diversity of terms used in different districts, 
 almost every locality having a complete set of its own, 
 
308 METALLURGY OF IRON. 
 
 which, as a general rule, are only current within a 
 limited area. The reason of this becomes apparent, 
 when we consider that iron-making in the olden times 
 was carried on in remote districts, where wood and 
 water power could be easily obtained, as, for instance, 
 in the valleys on the flanks of great mountain ranges 
 of Central Europe, the small size and weight of the 
 finished bars, &c., requiring only the simplest means 
 for conveyance to market, such as could be found 
 in pack animals, without even the necessity for roads 
 passable for wheeled carriages. In this way each 
 district may have developed its own process without 
 knowledge of what was doing in the same matter else- 
 where ; and the local experience would be incorporated 
 as a technical language, whose use would be confined 
 to a small class of workmen on the spot. 
 
 The introduction of the puddling furnace, and the 
 necessity of good roads for the economic transport of 
 materials to and from the forge, have had the effect of 
 bringing iron manufacture from the seclusion of the 
 valley to the high road, and as a consequence of the 
 change, an almost exact uniformity of language has 
 been introduced, all the terms connected with the 
 puddling furnace and rolling mill originating in Eng- 
 land having been adopted in foreign countries, in many 
 cases even without alteration, or at most have been 
 literally translated. 
 
 The gradually- increasing scarcity and consequent 
 rise in the price of wood, together with the increase 
 of facilities for conveyance of coal to works at a dis- 
 tance, have led to the abandonment of the open-fire 
 method of finery in many districts, as, for instance, in the 
 Eifel and Walloon countries ; and even in Scandinavia, 
 although carried to a high degree of perfection, it is 
 
PRODUCTION OF WROUGHT IRON IN OPEN FIRES. 309 
 
 giving way before the puddling and other modern 
 processes, which are susceptible of greater economy in 
 working. 
 
 The numerous methods of hearth finery which have 
 been alluded to above may be classified under three 
 heads, according to the number of times that the 
 metal requires to be broken up or lifted, from the melting 
 down of the charge to the preparation of the ball for 
 hammering ; that is, as single, double, or manifold 
 running-down processes (einmal, zweimal, or mchrmal 
 schmeherei). The distinction between these is in great 
 part due to the number of furnaces employed. Thus in 
 the last, of which the old German or Walloon forge 
 may be taken as the type, the three operations of refin- 
 ing, or conversion of grey into white metal, lifting and 
 fining proper, or breaking up, and the final balling, are 
 performed in the same hearth ; in the second, or double 
 process, the metal is run into the finery or blooming 
 hearth from a melting finery or running- out fire ; and 
 in the first, or single process, which is used in Styria 
 with white pig iron approximating in composition to 
 refined metal, the removal of the combined carbon is 
 effected chiefly by special oxidising agents without 
 much working before the twj T er : the product is a steely 
 iron, whose excess of carbon is afterwards removed by 
 subjecting the bloom to several welding heats. 
 
 A further distinction of these processes is founded 
 upon the method adopted in working the iron as it fines, 
 or, as is said in English, comes to nature. Thus, with metal 
 of a good quality, the whole charge may be allowed to 
 c,ome up together by lifting and working it in one mass 
 before the twyer, whereas with a lower quality the 
 particles of iron, instead of being allowed to coalesce a3 
 they form, are broken up into several masses, which, 
 after having being refined separately, are worked into 
 
310 METALLURGY OF IRON. 
 
 one ball as before, or each, one may be forged alone 
 into a bloom of smaller size. 
 
 The slags produced in the earlier part of the pro- 
 cess, as well as those of the refinery, as a rule approxi- 
 mate in composition to tribasic silicates of protoxide 
 of iron, with variable quantities of manganese and 
 earthy bases, according to the character of the pig iron 
 under treatment. Towards the end they become more 
 basic, and at last a difficultly-fusible substance, contain- 
 ing from 75 to 85 per cent, of protoxide of iron, remains 
 in the hearth. This, together with the more fluid, but 
 also basic slag expressed from the ball by hammering, 
 is employed as a decarburising agent. 
 
 The construction of hearth fineries is subject to a 
 certain amount of modification in different localities. 
 In the simplest, or old German forge, already alluded 
 to, the top of the hearth is near the ground level, and 
 the flame escapes directly into an open hood, like that 
 of an ordinary smithy fire ; but in the more improved 
 forms adopted in the Tranche Comte and Lancashire 
 forges used in Sweden, the hearth proper is covered 
 with a cylindrical roof, and communicates by a lateral 
 flue with a brick chimney. A portion of the waste 
 heat of the flame is economised by causing it to pass 
 over the pig iron forming the next charge, which is 
 placed in the flue, and is raised to a strong heat, and 
 partly oxidised. It is found that this preliminary 
 heating causes a considerable saving, both of fuel 
 and time, in the subsequent process of fining, being 
 somewhat similar in effect to the refinery. The flame 
 is also used in heating the blast, for which purpose a 
 coil of cast-iron pipes is placed, either above the hearth, 
 or between it and the base of the chimney stack. 
 
 The Bergamask forge process, used in the neigh- 
 bourhood of Bergamo, Brescia, and Lecco, in Northern 
 
PRODUCTION OF WROUGHT IRON IN OPEN FIRES. 311 
 
 Italy, differs from those already noticed by the large use 
 made of oxidising substances, and may be regarded as 
 bearing the same relation to them that the modern or 
 boiling system of puddling does to the original or dry 
 process. The charge of pig iron, when melted and 
 cleared from the supernatant cinder, is mixed with rich 
 forge slag, which reduces it to a pasty consistency, re- 
 moved from the hearth, and cooled with water. The 
 partially- refined product is then exposed in small por- 
 tions in the same hearth, after making up the fire, to a 
 low heat, sufficient to agglutinate the iron and cinder 
 into a cake, which is again taken out and cooled. In 
 the third stage, each of these cakes, or cotizzi, is refined 
 in the ordinary way, but with the addition of a further 
 quantity of rich slag or cinder. 
 
 Owing to the intermittent nature of the process, the 
 hearth having to be twice heated and cooled in each 
 operation, the consumption of fuel is considerable, being 
 nearly two and a half times the weight of the finished 
 bars. The loss of iron estimated on the pig is 4J per 
 cent., or, taking into account that contained in the 
 cinder added, from 18 to 19 per cent. The charge 
 weighs 5 cwt., and produces in one operation, lasting 
 eighteen hours, about eighteen finished bars, weighing 
 from 25 to 30 Ibs. each. 
 
 The pig iron employed is smelted from mangane- 
 siferous spathic ores occurring in the triassic rocks near 
 the lake of Como, in stratified masses, of which five are 
 known, the greatest individual thickness of 27 feet 
 being observed in the bed of La Manma, in the valley 
 of Dezzo. 
 
 In South "Wales, a superior quality of iron, adapted 
 for rolling into thin sheets for use in the manufacture 
 of tin plates, is made in the charcoal finery. The 
 
312 METALLURGY OF IRON, 
 
 metal treated is usually of a good class, such as t1~at 
 smelted with an .hracite or coke ; in the latter case, with 
 cold blast fron Welsh mine or hematite pig. The 
 charge, weighing generally from 5 to 6 cwt., is first 
 heated in a small coke refinery about 18 inches square, 
 with two twyers, and, after the requisite amount of 
 blowing, is run off" by an inclined gutter into the 
 charcoal fineries, of which there are two, placed in front 
 of and a little below the running- out fire. These 
 hearths are made of cast-iron plates ; the bottoms are 
 hollow, and cooled by a current of air. Three of the 
 sides are vertical; the fourth, or working side, is 
 slightly inclined upwards and outwards. The charge 
 of fine metal is equally divided between the two hearths, 
 which are each blown by a single twyer. Although 
 cold blast is used, the nozzle is protected by water 
 twyers, both in the refinery and charcoal hearths. 
 The fining appears to be done dry, that is, without the 
 addition of slag or scale, by continual breaking up and 
 raising the iron with a pointed bar ; the slag, or cinder, is 
 tapped off two or three times during the operation v 
 which lasts from one hour to one and a quarter. The 
 whole of the charge is worked into a single ball, 
 weighing somewhat less than 2 cwt., which is 
 shingled and drawn under a lever hammer to a long 
 bar, about 1J or 2 inches thick, and then broken into 
 pieces, called stamps, weighing about J cwt. each, 
 by nicking the bar half through, and striking the 
 weakened part with a sledge hammer. This method of 
 breaking up the bar affords a ready means of selecting 
 the iron by the appearance of the fracture, only such por- 
 tions as present a fine uniform crystalline grain being 
 used in the formation of the pile from which the 
 finished sheet is made. A similar process of stamping 
 
PRODUCTION OF WROUGHT IRON IN OPEN FIRES. 813 
 
 and selection of rough bars is in use in those forges of 
 the Wost Eiding of Yorkshire that are noted for the 
 high quality of fcheir malleable iron. 
 
 The reheating or welding of the stamps is effected 
 in a special furnace, known as the hollow fire, interme- 
 diate in character between the old chafery and the 
 modern reheating furnace. It consists of a deep rect 
 angular hearth roofed over at the top. The upper 
 part forms a chamber, in which the piles are reheated. 
 The lower part of the hearth is filled with coke, which 
 is burnt by a blast of air introduced by an inclined 
 twyer, near the top of the fuel, in the ordinary way. 
 The piles consist of fragments of the broken bars, or 
 stamps, obtained in the preceding operation, and are 
 supported on a flat plate or staff in the upper part of 
 the fire, clear of the top of the fuel, but fully 
 exposed to the flame. If the blast is introduced at a 
 lower point, so that the air has to traverse a certain 
 thickness of ignited fuel, the conditions of combustion 
 become similar to those of a gas generator, and the 
 furnace approximates to a gas reheating furnace with 
 the top blast omitted. A portion of the waste flame is 
 economised by the use of a second heating chamber, 
 where the pile receives a preliminary heating before it 
 is brought up to the welding temperature. 
 
 In Sweden, three principal methods of charcoal 
 finery are in use : the German, or rather Walloon, the 
 Tranche Oomte, and the Lancashire processes. The 
 first of these is confined to those forges that produce 
 the Dannemora steel irons. The hearth is not covered, 
 and the fining, which takes place in a bath 0* slag, is 
 much accelerated by almost continuous breaking up 
 and stirring of the molten metal. The bloom is of 
 small size, weighing only about 100 Ibs., and is pro- 
 
 p 
 
814 METALLURGY OF IRON. 
 
 duced in from twenty-five to thirty minutes. The pig 
 iron of a white or strongly-mottled character is not 
 charged and melted down in one quantity, but is used 
 in the form of slabs or bars from 15 to 18 feet long. 
 Only the fore-end of the slab is exposed to the fire, so 
 that the metal melts and runs down in drops before the 
 blast like sealing-wax in the flame of a candle, the 
 end, as it wastes, being kept in the same position by 
 pushing forward. The bloom obtained from the 
 previous heat is reheated for the first time in the fore- 
 part of the hearth during the period of melting, being 
 held with tongs in an inclined position : the subsequent 
 heats, to the number of six or seven, required in 
 drawing it out into a bar under the hammer, are 
 effected in a separate fire. The consumption of char- 
 coal is very large, being three times the weight of the 
 bar iron produced ; the loss of weight, or difference 
 between the latter and the pig iron used, is from 20 to 
 25 per cent. 
 
 The Franche Comte and Lancashire processes are 
 conducted in covered hearths with flues for heating up 
 the charge of pig iron previous to melting, and stoves 
 for the blast, which is raised to a temperature of about 
 100 ; the pressure is from 1 Ib. to ]\ Ib. The princi- 
 pal difference between them is that in the former the 
 reheating of the bloom, which is cut into two pieces 
 after shingling, is effected in the same fire, while in the 
 Lancashire forge either a second hearth, or what is 
 now more usually the case, a gas- welding furnace, is 
 used for this purpose. The proportional yield is about 
 the same in both cases, the weight of bar iron produced 
 being about 15 per cent, less than that of the pig iron 
 used. The consumption of charcoal is, under the most 
 favourable conditions, about the same in either pro- 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 315 
 
 cess, being one and a half times the weight of the 
 finished bars, or only half as much as in the "Wal- 
 loon forge. 
 
 CHAPTER XV. 
 
 REVERBERATORY FINERY OR PUDDLING PROCESS. 
 
 THE use of the reverberatory furnace, instead of the 
 open fire or hearth, in the conversion of cast into 
 malleable iron, was introduced by Oort in 1784, and has 
 now almost entirely superseded the older processes in 
 those localities that are chiefly dependent upon mineral 
 fuel. Even in wooded districts its use is becoming 
 general, more especially since the introduction of gas 
 furnaces, which are capable of being worked with fuel 
 of inferior quality and heating power such as wood, 
 brown coal, peat, &c. when converted into carbonic 
 oxide, such substances being unfit for use in fineries 
 where the heat is produced by combustion of the fuel 
 in contact with the iron. 
 
 The reactions going on during the operation of 
 puddling are substantially the same as those observed 
 in hearth fineries, the decarburisation of the pig iron 
 being effected by the joint action of a current of air 
 produced by the draught of a chimney, instead of being 
 blown in under pressure from a twyer, and oxidising 
 fluxes, such as hematite, magnetic oxide of iron, forge 
 scale, or the molten slag, a highly basic silicate of 
 protoxide of iron. 
 
 According to the relative importance of the parts 
 played by these agents, the process is divided into dry 
 and wet puddling, the former being dependent mainly 
 
316 METALLURGY OF IRON. 
 
 on the exposure of the metal to the action of the air, 
 while in the latter, which is more generally known as 
 the pig-boiling process, the slag and oxide of iron added 
 are the most important oxidising agents. 
 
 As the charge of melted pig presents a larger surface 
 for the same weight in the puddling furnace than is 
 the case in the open fire, it forms a thinner layer, and 
 therefore can be more readily brought into contact 
 with the air ; the operation of fining is more quickly 
 performed ; and the labour of lifting, &c., although very 
 severe, is less so than in the hearth finery, especially 
 in the treatment of grey iron. The conversion of the 
 latter into white metal by a preliminary fusion in the 
 refinery is, however, equally advantageous in either 
 case. 
 
 The general details of the construction of the pud- 
 iling furnace, are shown in the four figures (Fig. 
 25), A, B, c, and D. The fireplace is of rectangular 
 form, built of fire-bricks, and divided from the hearth 
 by a low wall or fire-bridge. The roof of the furnace 
 is curved to a flat arch, and is generally made to 
 slope at a small angle towards the flue. The whole 
 of the brickwork is cased with side plates of cast 
 iron, united by flanges and bolts, and bound together 
 with wrought-iron tie-rods across the top. The bottom 
 of the bed is formed of plates of cast iron, united by tenon 
 joints, and supported upon dwarf pillars or standards 
 of the same metal. The sides of the bed may be 
 variously constructed, the differences being due to 
 variations in the methods of artificial cooling adopted. 
 In the furnace in question they are formed of hollow 
 iron castings, united into a rectangular tube, through 
 which a current of air circulates for the purpose of 
 protecting the metal against the intense heat of the 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 317 
 
 furnace. The bed is terminated at either end by a 
 straight wall or bridge : that nearest the fireplace is 
 called the fire-bridge, and the opposite one the flue- 
 briclge ; both are built of fire-brick, overlapping the top 
 
 Fig. 25. Puddling furnace. 
 
 A. Vertical section through the centre. B. Plan at level of bed. 
 D. End elevation of fireplace. 
 
 c. Side elevation. 
 
 of the side frame, so as to form a recess for the recep- 
 tion of the refractory material used in lining or fettling 
 the sides. 
 
 The fire grate presents no peculiar features; it is 
 made of plain wrought-iron bars placed horizontally, 
 and carried at either end by transverse bearers. The 
 depth of the fireplace varies with the nature of the 
 
318 METALLURGY OF IKON. 
 
 fuel employed, being greatest with the least bituminous 
 kinds of coal, in such cases, especially, where anthra- 
 cite is burnt. A forced draught, produced by blowing 
 air in below the grate, may be sometimes used to ad- 
 vantage. With peat, brown coal, or slack, inclined or 
 step-grates are used, and by the combination of these 
 accessories the indirect or gas furnace is produced. 
 The best fuel for furnaces with ordinary grates is coal 
 of a dry, non-caking quality, burning with a long 
 flame, as free from sulphur as possible. The surface of 
 the grate should be between one-half and one -third of 
 that of the bed, which, taking the latter at 20 square 
 feet, would give from 7 to 8 square feet. The amount 
 of coal burnt is from l to 2 cwt. per hour. The 
 charging or fire-hole is 10 inches above the grate ; it 
 has no door, but is stopped with lumps of coal when 
 the fire is lighted. 
 
 The flue is usually built with a slope towards the 
 stack ; the sectional area varies with the nature of the 
 fuel, being about one-fifth of that of the grate for bitu- 
 minous coal, and one-seventh for anthracite. Some- 
 times a second bed is placed behind the flue-bridge, 
 upon which the pig iron destined for the following 
 charge is subjected to a preliminary heating or roast- 
 ing, by the flame passing over it on its way to the 
 stack, in order to save time in the subsequent melting 
 down. In like manner, when a blast is used above the 
 grate, as in gas furnaces, it may be heated by meang 
 of a coil of horizontal V-shaped pipes of cast iron, placed 
 on the lower part of the stack in the course of the 
 flame, or by circulation through the hollow side frames. 
 
 The stack is usually from 30 to 50 feet high, and about 
 20 inches square, when it serves only a single furnace ; 
 but when the several flues are led into one, especially 
 
REVERBERATORY FINERY OR PUDD7.ING PROCESS. 319 
 
 when a part of the heat is taken away by passing the 
 flame under steam boilers, it is necessary to increase 
 the height to 100 feet or more, in order to overcome 
 the additional resistance. The walls of the stack are 
 of fire-brick, with an outer casing of common brick- 
 work, which is tapered in thickness, being set back in 
 steps at two or different heights; the lower part is 
 often supported on cast-iron columns or standards. 
 The draught is regulated by a flat plate or damper at 
 the top of the stack, attached to one arm of a lever, 
 which can be raised or lowered by means of a chain 
 attached to the opposite arm, which hangs nearly down 
 to the ground level. 
 
 The working door, which is on the same side of the 
 furnace as the fire-hole, is made of fire-clay slabs set in 
 a cast-iron frame, and is suspended by a chain to a lever, 
 carrying a counterbalance weight at the opposite end, 
 in order that it may be readily lifted and lowered. It is 
 only opened during the introduction of the charge and 
 the removal of the puddled balls. A small rectangular 
 or arched notch, called the stopper hole, is cut out of the 
 edge for the introduction of the tool used in stirring or 
 rabbling the bath of metal. The sill of the door is 
 about 10 inches above the level of the bottom of the bed ; 
 below it is placed the tap-hole, through which the slag 
 or tap cinder is withdrawn from the hearth. During 
 the operation it is plugged up with sand in the usual 
 way. A portion of the cinder also overflows the flue- 
 bridge, and runs down the inclined surface of the flue 
 to the bottom of the stack, where it is allowed to accu- 
 mulate. 
 
 The side of the bed opposite to the working door 
 is of a curved form, and is not directly accessible from 
 the exterior in the ordinary or single furnace. In 
 
320 METALLURGY OF IROX. 
 
 large forges it is usual to place two furnaces together 
 in one block, back to back, with their working sides 
 facing in opposite directions. The larger or double 
 furnaces have working doors on both sides, so that two 
 sets of puddlers can work at the same time, the weight 
 of the charge being of course proportionately increased. 
 In some few instances the beds have been made of 
 such a size as to admit of working from four points 
 simultaneously. It is doubtful, however, whether any 
 advantage is to be got from the increased dimensions, 
 as the saving of fuel and time claimed can only be 
 realised by employing men of uniform skill, and 
 capable of working off their heats in exactly the same 
 time, otherwise a large loss of iron from burning is 
 likely to ensue when one man brings out his heat 
 before the other. 
 
 The working bed, or lining of the hearth, was formerly 
 covered with sand, but is now usually made of re- 
 fractory slags rich in oxides of iron, such as are 
 obtained at the end of the process, the remains of old 
 beds of a similar character, mill or hammer slag, or 
 burnt scrap iron. In making a new bed, the cast-iror 
 bottom-plate is covered with a layer of broken slags, 
 3 to 5 inches in thickness, which is then softened 
 by long- continued heating, the surface being rendered 
 smooth by working with a flat bar or paddle. When 
 scrap iron is used, a quantity of about 4 cwt. is thrown 
 into the furnace, which is then raised to a strong heat. 
 The ball formed by the agglomeration of the particles 
 of iron is worked down and spread as uniformly as 
 possible over the entire bottom, care being taken to 
 maintain a high temperature and oxidising atmosphere 
 in the furnace during the operation. The thickness of 
 the finished coating should not exceed 1 or t J inches. 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 321 
 
 Sometimes the bottom-plate is coated with a thin layer 
 of fire-clay before the lining is introduced. 
 
 Grey pig iron should not be puddled alone upon a 
 new bed ; the first charges should consist of scrap iron 
 or waste blooms, and refined metal in small quantities, 
 until the refractory lining has become sufficiently consoli- 
 dated, by continued oxidisation and a high temperature, 
 to resist the solvent action of the silica produced from 
 the oxidation of the silicon contained in the pig iron. 
 
 The side-plates of the hearth are lined or fettled in 
 a similar manner with butt-dog, a mixture of peroxide 
 of iron and silica, produced by roasting tap cinder, 
 hematite, or magnetic iron ore. Limestone is sometimes 
 used for this purpose, but does not appear to be gene- 
 rally advantageous, except as being less liable to waste, 
 as it does not contribute to the decarburisation of the 
 metal, and thickens the slag, and may prevent welding, 
 producing a red short iron if mixed accidentally with 
 the ball. The side linings are subject to considerable 
 wear, and require to be repaired after each heat. For 
 this purpose small heaps of fettling materials are placed 
 by the side of each furnace. The larger holes are filled 
 with lumps of crushed bull-dog, after which the surface 
 is made smooth with puddler's mine, usually a soft red 
 hematite, which is mixed to a paste with water. In 
 Cleveland, besides the ordinary fettling materials, burnt 
 pyrites, residues from the sulphuric acid works, called 
 "Blue Billy," and finely-crushed Swedish magnetic 
 iron ore, are in use. 
 
 Although the process of puddling is susceptible of 
 considerable modification according to the nature of 
 the pig metal employed, and that of the iron which it 
 is desired to produce, it may be generally stated to in- 
 clude the following operations : 
 
 pa 
 
322 METALTJTTIGY OF IRON. 
 
 1. Melting down of the charge, with or without 
 previous heating. 
 
 2. Incorporation of oxidising fluxes with the charg 
 at a low heat. 
 
 3. Elimination of carbon, by stirring the contents of 
 the furnace at a high temperature. 
 
 4. Consolidation of the reduced iron to masses or balls 
 fit for hammering. 
 
 The regulation of the temperature, and the amount of 
 air passage through the furnace by the damper, is a 
 point of considerable importance. The heat requires to 
 be greatly raised towards the end, at the same time 
 preventing an unnecessary influx of air, which would 
 burn the iron to waste. In gas furnaces this is done 
 by shutting off the top blast, so that the hearth is 
 filled with an atmosphere of heated gas containing 
 unconsumed carbonic oxide. 
 
 The following is a generalised description of the steps 
 ordinarily pursued in puddling : When the furnace is 
 charged, the working door is shut and secured in position 
 by iron wedges ; sometimes the joint is luted with clay; 
 the fire is made up after cleaning and pricking the grate ; 
 the fire-hole is stopped with lumps of coal and slack, in 
 order that no air may enter the furnace except through 
 the space between the grate bars during the period of 
 melting down. In about a quarter of an hour the metal 
 begins to soften ; the puddler then introduces a bar or rab- 
 ble through the opening in working door, and moves the 
 unmelted lumps from the sides into the middle of the bed, 
 in order to bring the whole more quickly into a state of 
 uniform fluidity, the fire being increased at the same time 
 for about four or five minutes. As soon as the metal is 
 completely melted, it is rendered uniform by stirring, 
 the temperature being lowered by partially closing the 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 323 
 
 damper, until the surface of the bath is protected by a 
 coating of slag against the direct action of the air. 
 The amount of handling required in this part of the 
 process depends upon the nature of the metal operated 
 upon. With grey pig, which requires a higher tem- 
 perature for fusion, but which runs very liquid, the 
 fragments may be distributed uniformly over the bed, 
 and melted down without being moved, if the furnace 
 is sufficiently hot ; but otherwise, a pile of metal is 
 formed close to the fire-bridge, and as the temperature 
 increases, the unmelted portions are drawn back into 
 the centre, and pressed down below the surface of the 
 slag. 
 
 When white or refined metal is used, it is said to be 
 an advantage to bring the furnace to a high heat by 
 firing up strongly for about a quarter or half an houi 
 before introducing the charge ; the fusion takes place 
 more rapidly, and with less oxidation of iron, than is 
 the case in the ordinary way. 
 
 In order to bring about the reaction of the slag upon 
 the melted metal, it is necessary to incorporate the 
 whole contents of the furnace well together after melt- 
 ing. For this purpose the temperature is lowered by 
 checking the draught, or even throwing water upon 
 the metal, the charge being stirred at the same time. 
 The slag is also reduced to a more basic condition by 
 the addition of scale or mill cinder, to compensate for 
 the silica produced from the oxidation of silicon in the 
 pig, which, as we have already seen, always separates 
 when the fusion takes place in an oxidising atmosphere. 
 When the mixture is complete, and the mass is some- 
 what stiffened, the reaction of the oxide and silicate 
 of iron upon the combined carbon is apparent by the 
 escape of blue flames of carbonic oxide; and as the 
 
324 METALLURGY OF IRON. 
 
 temperature is increased by opening the damper, the 
 whole of the surface of the metal commences to boi] 
 from the rapid escape of gas, and rises above the level 
 of the working door, at the same time a portion of the 
 molten slag flows out. The action is facilitated by con- 
 stant stirring with the rabble or hooked bar. The 
 puddler searches or sweeps every portion of the bed 
 by moving the point of the tool in curved lines from 
 the centre outwards towards the bridges on either side, 
 commencing at the front. The sides are reached by 
 a kind of scooping action, the rabbles being worked 
 against the door-frame as a fulcrum. The tool must 
 be changed every five or ten minutes, or it would 
 soften and adhere to the iron if left too long in the 
 furnace. When taken out it is cooled by plunging into 
 a cistern or water bosh, which detaches the adherent 
 cinder ; the point is afterwards dressed up into shape 
 by forging with a light hammer. Usually four tools 
 are required to be used in the boiling of one charge. 
 
 As the carbon diminishes the ebullition becomes less 
 violent, and the bath, from its reduced fusibility in. 
 spite of the high temperature, begins to stiffen, and 
 malleable iron separates, or, as it is called, comes to 
 nature in the form of bright points, which increase to 
 spongy masses projecting from the bath of melted slag. 
 Owing to the high temperature and the fine state of 
 division in which it is exposed to the oxidising atmo- 
 sphere of the furnace, the reduced metal is raised to a 
 brilliant white heat by partial combustion. At this 
 point of the process it is necessary to regulate the 
 fining by preventing the too rapid agglomeration of 
 the reduced iron ; the whole contents of the furnace 
 require, therefore, to be stirred and broken up again, 
 so that every part may be brought under the influence 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 325 
 
 of the high temperature prevailing in the neighbour* 
 hood of the flue-bridge, at the same time any pasty 
 lumps of iron that may have adhered to the sides are 
 detached. The reduced mass is subject to a final heat, 
 in order to facilitate the separation of the cinder by 
 rendering it perfectly fluid. 
 
 The last operation consists in forming up the balls, 
 which is done by detaching from the reduced iron 
 masses of usually from 60 to 80 Ibs. weight each, and 
 pressing them together with the tool until they are 
 sufficiently coherent to be moved without falling to 
 pieces. This may be done either by pressing against 
 the bottom and sides of the furnace, or by a rolling 
 motion, the iron being gathered up around a small 
 nucleus like a snow-ball. 
 
 As soon as a ball is made it is placed close against 
 the fire-bridge, and in order to keep it out of the 
 draught of air between the working door and the flue, 
 the second is proceeded with until the whole of the 
 charge has been balled up ; the working door is then 
 closed, and the final heat is given. 
 
 The removal of the balls, which are of a roughly 
 spherical form, after they are drawn to the working 
 door with the tool, is effected by means of a long pair 
 of tongs with curved jaws. They are first lifted to 
 the table in front of the working door, and afterwards 
 either dragged along the floor or carried on a wrought- 
 iron truck to the hammer, or such other shingling 
 machine as may be employed. After the removal, and 
 during the shingling of the first ball, the damper and 
 working door are shut, in order to protect those re- 
 maining in the furnace from unnecessary waste by 
 oxidation while waiting their turn for hammering. 
 
 The old system of puddling pig iron on a dry bed 
 
326 METALLURGY OF IROX. 
 
 is only applicable to white or refined metal : the chief 
 difference between it and the method of boiling consists 
 in the comparatiyely small quantity of slag formed. 
 As soon as the metal has got into the pasty state it is 
 broken up and constantly stirred, in order to incor- 
 porate the oxide of iron, formed during the melting 
 down, with the metal. The contents of the furnace are 
 not allowed to become perfectly fluid, and the work 
 goes on continuously from the commencement of the 
 stirring to the balling up. Although there is less loss 
 of iron, and a smaller consumption of fuel, owing to 
 the rapidity with which the operation is performed, 
 than is the case in the boiling process, the iron pro- 
 duced is likely to be of an inferior quality, unless a very 
 good description of pig is used. The actual use of 
 sand bottoms is almost obsolete, as they give rise to a 
 great waste of iron, the process being usually conducted 
 on an iron bottom with a thin coating of cinder. 
 
 According to Truran, 1 ton of puddle bars is pro- 
 duced by 21 cwt. 1 qr. 20 Ibs. of fine metal by the dry 
 puddling, and , 21 cwt. 3 qrs. by the boiling process. 
 The former lasts from 1 to 1? hours, and the latter 
 from 1J to 2 (hours. 
 
 The excellence of the iron produced depends mainly 
 upon the prevalence of a high temperature during the 
 period of .boiling, when the heat is continued during 
 the balling by keeping the damper open, in order to 
 maintain an oxidising atmosphere in the furnace ; de- 
 oarburisation is promoted, and soft or fibrous iron is 
 obtained. On the other hand, when the draught is 
 checked after boiling by partially closing the damper, 
 the hearth is filled with neutral or reducing flame from 
 the imperfect combustion of the gases produced by 
 the fuel, and a further elimination of carbon is pre- 
 
REVERfiERATORY FINERY OR PUDDLING PROCESS. 327 
 
 vented. The result in this case is a hard or steely iron, 
 which breaks with a finely crystalline fracture, raid 
 may be considered as intermediate in character between 
 soft iron and steel. By diminishing the time of boiling, 
 and working at a low temperature, another form of 
 granular crystalline iron may be obtained, which is 
 hard, but deficient in tenacity, and only fit for the body 
 or central part of common rails, where it is exposed 
 chiefly to a compressive strain. 
 
 Although the nature of the iron obtained is greatly 
 dependent upon the manipulation, as much or more is 
 due to the quality of pig iron operated upon. The 
 greater the amount of impurities, especially sulphur 
 and phosphorus, the longer will the puddling last, and 
 consequently, the greater will be the waste of metal. 
 With metal of low quality it is scarcely possible to 
 produce good steely iron, as the decarburisation must 
 be pushed to the utmost in order to remove other 
 foreign substances. 
 
 The quantity of slag produced in puddling varies 
 with the metal treated. With grey pig it is greatest, 
 as the combined silicon takes up about six times its 
 weight of iron in order to form a fusible silicate ; while 
 refined metal, having been previously deprived in great 
 part of its silicon in the refinery fire, makes much less. 
 The more nearly the slag approaches in composition to 
 a neutral (tribasic) silicate, the greater will be its 
 fluidity, and the less its decarburising influence upon 
 the molten pig iron, as compared with the more basic 
 slags, containing peroxide or magnetic oxide of iron 
 in excess, which are produced towards the end of the 
 process. The presence of other bases in the slag, espe- 
 cially protoxide of manganese, have a similar effect in 
 preventing the removal of carbon, as they increase the 
 
328 METALLURGY OF IRON. 
 
 fluidity, so that the bath of molten slag screens the 
 surface of the metal from the direct action of the air, 
 without introducing the compensating oxidising agency 
 of kindred oxides upon the combined carbon, oxide of 
 manganese being undecomposable by carbon in an 
 oxidising atmosphere. It is on account of this pro* 
 perty that the presence of manganese is of great value 
 in pig iron which is intended to be converted into steel 
 by puddling. 
 
 As the fluidity of puddling-furnace slags diminishes 
 with the increase of bases, it is advisable not to work 
 with refined metal alone, as in that case the hearth 
 bottom becomes covered after a time with an almost 
 infusible layer of highly basic slag, like the lull-dog 
 used in fettling. This inconvenience is to be avoided 
 by adding a certain proportion of grey or white pig 
 iron containing silicon to the charge of fine metal. 
 Under ordinary circumstances, in puddling grey pig, 
 the cinder is tapped off at every second heat ; but with 
 fine metal the quantity formed is so small that it may 
 remain. 
 
 The chemi'cal changes involved in the process o/ 
 puddling have been investigated by Calvert and John-, 
 son, Lan, Schilling, and Drassado, both in England, 
 France, and Germany. The method followed by these 
 chemists was similar in all cases. Samples of the iron 
 and slag taken from the furnace at different times 
 during the puddling of one charge were analysed, and the 
 results tabulated. The order in which the foreign 
 bodies are removed can then be seen by comparison of 
 the analyses, assuming, of course, that the samples re- 
 present the average composition of the contents of the 
 furnace at each period. In the boiling process, the 
 oxidation of carbon is effected chiefly in an indirect 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 323 
 
 manner by an excess of protoxide, or rather magnetic 
 oxide, of iron contained in the slag, which oscillates in 
 composition from a more acid to a more basic character 
 at different stages of the process. Thus the amount of 
 silica in the slag may be increased absolutely, at the 
 commencement of the process, by the oxidation of silicon 
 during the melting of the pig iron; and relatively, during 
 the boiling part of the process, owing to the partial 
 reduction by the carbon of the pig iron of the oxides ot 
 iron held in combination. On the other hand, the 
 slag becomes more basic towards the end, when the 
 carbon has been removed, and the reduced iron com- 
 mences to burn, owing to the intense heat necessary 
 during the operation of balling. The removal of the 
 foreign matters in combination with the iron takes 
 place in the following order : first, silicon ; then man- 
 ganese, then phosphorus ; and, lastly, sulphur ; the latter 
 element being most difficultly removable. In the treat- 
 ment of grey pig iron, the graphitic carbon is trans- 
 formed into the combined condition after the removal 
 of the silicon during the melting of the charge ; a 
 change that has already been noticed as occurring at 
 the same stage in all refinery processes. 
 
 The cause of the removal of phosphorus from iron in 
 the puddling process is not well explained. Percy 
 supposes that it may be effected by liquation as a fusible 
 phosphide of iron, which sweats out of the pasty mass of 
 the ball and passes into the slags, where the phosphorus 
 is oxidised to phosphoric acid. When a sufficiently 
 high temperature can be commanded to melt malleable 
 iron, as is the case in Bessemer's process, the whole of 
 the phosphorus present in the pig iron is retained in 
 the product. This appears to be true for any kind of 
 iron. 
 
330 METALLURGY OF IKOX. 
 
 The addition of oxidising fluxes other than the com- 
 pounds of iron already noticed has been advocated as 
 a method of improving iron in the puddling furnace. 
 The chief of these is the mixture of salt, peroxide of 
 manganese, and clay, known as Schafhautl's powder, 
 which is recommended as an addition in the boiling 
 process, at the rate of about 14 Ibs. to an ordinary charge 
 of 3| or 4 cwt. of pig iron. The oxygen given off by 
 the peroxide of manganese and the chlorine of the salt 
 are said to act directly upon arsenic, sulphur, and 
 phosphorus, with the production of oxides or volatile 
 chlorides ; while the bases, alumina, protoxide of man- 
 ganese, and soda, pass into the slag, giving it increased 
 fluidity. The latter is probably the true reason of the 
 efficacy of this flux. Sulphate of iron has also been 
 recommended for the same purpose. 
 
 In Staffordshire two hands (puddler and underhand), 
 in a turn of twelve hours, work off 'from five to seven 
 heats, the charge being from 4 to 4J cwt. The smaller 
 number refers to grey pig, and the larger to mixtures 
 containing from one-third to one-fourth by weight of fine 
 metal. The loss of weight between the pig iron charged 
 and the puddled blooms or bars produced is from 1 j 
 to 2 cwt. per 22 cwt. of pig metal, or from 7 to 10 per 
 cent. The coal burnt amounts to between 20 and 22 
 cwt. per ton of puddled bars. The fettling materials 
 required in the turn of twelve hours for keeping the 
 bed in proper order are from 6 to 7 cwt. of bull-dog, 
 and 2 to 3 cwt. of puddler's mine, in addition to the 
 mill scale added to the charge. 
 
 In Scotland, where dark grey metal rich in silicon 
 is used without being previously refined, only from 
 four to five heats of 4 cwt. are made in the same time. 
 The loss of weight is from 15 to 18 per cent, from pig 
 
KEVEIIBERATORY FINERY OR PUDDLING PROCESS. 331 
 
 iron to puddled bars, and the consumption of coal per 
 ton of the latter from 25 to 26 cwt. When mixtures 
 of fine metal and grey forge pig, partly Scotch and partb. 
 hematite, are used, the results are generally similar to 
 those obtained in Staffordshire. In Cleveland, the 
 consumption of small coal (nuts) is from 24 to 27 cwt. 
 per ton of puddled bars. The whole of the above 
 quantities are in long cwts. of 120 Ibs. each. 
 
 In the West Riding of Yorkshire, in the neighbour- 
 hood of Leeds and Bradford, a very high quality of 
 wrought iron is made from cold blast refined metal by 
 puddling in small heats, the stirring being continued 
 longer than is usually the case, in order to obtain uni- 
 formity in the product. The furnace is of comparatively 
 small size, with a very high stack, in order to command 
 a strong heat. The charge, weighing 3 cwt., is heated 
 to redness before its introduction to the puddling 
 furnace, so that the melting down requires only from 
 twenty to twenty- five minutes, and the whole operation 
 about one hour and twenty minutes : nine heats are 
 made in twelve hours. The balling is performed as 
 much as possible in a reducing atmosphere, by closing 
 the damper, as the iron is of a bright crystalline steely 
 character, and is not decarburised to the same extent 
 as ordinary fibrous iron. Only three or four balls, 
 weighing from 80 to 90 Ibs. each, are obtained in one 
 heat, which, after shingling under a helve hammer 
 into plates or stamps from 10 to 12 inches square, and 
 about 2J inches thick, are broken into pieces by blows 
 from a heavy weight falling from a considerable height 
 These pieces or stampings are assorted according to the 
 fracture ; those that are most uniformly crystalline are 
 reserved for the manufacture of hard bars, such as 
 railway tires, while those showing fibre are better fitted 
 
332 METALLURGY OF IRON. 
 
 for making boiler plates and wire rods. The consump- 
 tion of coal is very large, being 30 cwt. per ton of fine 
 metal treated, or 37J cwt. per ton of blooms produced. 
 When the double furnace is used the charge is twice 
 the ordinary weight, or from 6 to 8 cwt., the time 
 required for working off the heat being the same. 
 
 In Belgium the average weight of the charge is 230 
 kilogrs. (4-6 cwt., short weight). According to the 
 quality of metal employed, the time required for each 
 heat is from 1 J to 2f hours, namely, 2 to 2f hours 
 with grey pig, If to 2J hours with white pig, and 1J 
 to 21 hours with fine metal. The loss of weight is 
 from 7 to 10 per cent. The coal burned is equal in 
 weight to that of the puddled bars produced. 
 
 The general arrangements of a gas-puddling furnace, 
 used in Carinthia are represented in the longitudinal 
 section, Fig. 26. The fuel is air- dried wood, which is 
 
 Fig. 26. Carinthian gas-puddling furnace. 
 
 converted into combustible gas in the generator a, a 
 rectangular chamber, lined with fire-brick, of a capacity 
 of about 14 cubic feet, by a stream of air introduced at 
 a pressure of half an inch of mercury, through the lower 
 branch of the blast main at b. The combustion of the 
 gases is effected by a second blast, introduced imme- 
 diately above the fire-bridge, through the inclined twyer 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 333 
 
 f , which is of an oblong form, extending completely 
 across the bridge, with an aperture of 7 inches in 
 depth. By previously circulating through the hollow 
 space in the cast-iron side plates of the bed, the air 
 is heated to a temperature of 200, producing a much 
 more active combustion than is the case when the gases 
 are burnt with cold air. A second bed is used for 
 heating up the metal for the following charge by the 
 waste flame during the period of balling, an arrange- 
 ment that, as has already been stated, is found to save 
 both time and fuel. The remaining details do not call 
 for any particular remarks, being of the ordinary kind 
 adopted elsewhere. 
 
 In Styria, where lignite is used for puddling, the 
 consumption is from 22 to 24 cwt. per ton of blooms, 
 a result that is highly favourable, not exceeding the 
 average of furnaces where coal is burnt, allowance being 
 made for the difference in calorific value of the two 
 classes of fuel. ThL is in great part due to the high 
 quality and small amount of carbon and silicon in the 
 pig iron operated upon. The heat of 4 cwt. is worked off 
 in an hour, having been brought to an orange-red heat 
 before melting by exposure in a second hearth, during 
 the balling of the preceding charge. The loss of 
 weight on the metal is from 6 to 10 per cent. 
 
 When peat is used, from 240 to 360 cubic feet are 
 required in the production of a ton of blooms, or from 
 200 to 280 cubic feet of wood. From the published 
 accounts of the working of furnaces using these fuels, 
 there does not appear to be much difference whether 
 they are burnt on a grate, or previously converted 
 into gas, in the manner described above. The most 
 economical work appears to be at Neuberg, in Styria, 
 where only 100 cubic feet of air-dried wood are con- 
 
334 METALLURGY OF IRON. 
 
 sumed in the production of a ton of blooms. The 
 metal, of a white or strongly mottled character, smelted 
 with charcoal from spathic ore, is puddled in a double 
 furnace, in charges of 8 cwt. ; the heat lasts two 
 hours, the loss of weight being from 5 to 6 per cent. 
 At Lippitzbach, in Tyrol, one ton of blooms is pro- 
 duced from 1*047 tons of pig iron, with a consumption 
 of 1 -Oil tons of wood scorched or torrefied. 
 
 In Staffordshire, a certain quantity of scrap iron is 
 sometimes added in the puddling furnace, in order to 
 improve the quality of the product as soon as the iron 
 comes to nature. When the fragments are at a white 
 heat, they are incorporated with the contents of the 
 furnace, which are then balled up in the ordinary way. 
 It is obvious that if the scrap added be of good quality, 
 it will have a beneficial effect, by spreading the 
 absolute amount of impurities contained in the puddled 
 iron over a greater weight of finished iron, and thus 
 producing a relatively purer article. 
 
 The work of the puddling furnace is divided between 
 the puddler and his underhand : the latter attends to 
 the firing, and also does part of the stirring or rabbling ; 
 the last and heaviest portion of the work, together with 
 the forming the balls, being usually done by the former. 
 The tools employed are principally of two kinds, 
 namely, long straight chisel-edged bars or paddles, and 
 hooked bars with similar flat ends or rabbles, weighing 
 about 60 Ibs. each. The number of tools used in the 
 working of one charge depends upon the quality of the 
 iron, and may vary from. Jiree or four to eight, accord- 
 ing to the amount of work required. "When with- 
 drawn from the furnace, the points are coated with 
 melted cinder, which is removed by quenching the bar 
 into a cistern of cold water or water bosh, placed by the 
 
KEVERBERATORY FINERY OR PUDDLING PROCESS. 835 
 
 side of the stack. The cinder deposited at the bottom 
 of the hosh is afterwards added to the charge in the 
 boiling process. 
 
 In order to lessen the great amount of labour involved 
 in working the charge, various mechanical appliances 
 have been proposed in substitution for manual puddling, 
 but these have not as yet been adopted to any great 
 extent. The different plans proposed for this purpose 
 may be classified under two heads, namely, those 
 imitating the motions of hand-stirring, by moving the 
 tool through a curved path by a combination of recipro- 
 cating rotatory mechanism, and those using rotating or 
 oscillating hearths. Of the latter kind are the furnaces 
 proposed by Tooth, Menelaus, Bessemer, and others. 
 The molten iron is fined by exposing it to oxidising 
 influences in a cylinder lined with clay, or other re- 
 fractory material, occupying the position of the hearth 
 in an ordinary puddling furnace, which receives a slow 
 movement of rotation about its long axis. The charge, 
 in addition to being turned o\er, is traversed from end 
 to end of the cylinder by inclining the lining from 
 the fireplace to the flue, and in the reverse direc- 
 tions at opposite points of the circumference. The ball 
 is withdrawn from the furnace by removing the 
 puddling chamber, and tilting it up on end. These 
 furnaces have not hitherto been successful, owing to 
 the difficulty of getting linings to stand the scouring 
 action of the metal. Menelaus found the best material 
 for this purpose to be titaniferous iron ore, which was 
 used in solid blocks. The ordinary fettling materials, 
 such as bull-dog, were quite useless. The above repre- 
 sents our knowledge of rotating furnaces when thia 
 work was written; how it has progressed since will 
 
336 METALLURGY OF IRON. 
 
 be seen by the account of Danks's and other furnaces at 
 p. 339. 
 
 One of the simplest of the first class of contrivances 
 or mechanical stirrers, by Eastwood, is represented in 
 Fig. 27. The rabbling tool, a, is suspended in a stirrup 
 at the end of the longer arm of a bent lever, which 
 receives an alternating motion by a rod, b, connected 
 with a crank on the main driving shaft. The centre 
 of oscillation of the bent lever is placed at the end of 
 
 Fig. 27. Eastwood's mechanical puddler. 
 
 an inclined jib, which can be moved laterally through 
 a small arc by another rod, c, working on a pin attached 
 to a screw-wheel, d, driven by a worm on the main 
 shaft. The action is as follows : Motion is given by 
 a chain passing over a pulley in the main shaft at e. 
 The rabble is moved backwards and forwards across 
 the hearth once in each revolution, at the same time 
 that its centre is shifted by the movement of the jib 
 
REVERBERATORY FINERY OR PUDDLING FKUCESS. 337 
 
 through a small distance by the screw gearing, thus 
 producing a compound motion in the tool, and causing 
 it to travel over every portion of the furnace bottom. 
 The machine is bolted to the back of the casing plate 
 on the working side of the furnace ; the driving pulley 
 is connected with the shaft by a fast-and-loose clutch, 
 /, so that it may be readily put in and out of gear 
 as required. 
 
 JKllerhau sen's process for simplifying the work of the 
 puddler, by the use of an intimate mixture of pig iron 
 and oxydfsing substances, such as hematite or mag- 
 netite, resembles the first operation of the Bergamask 
 forge process, with this difference, that the mixture of 
 molten iron and finely-divided flux is made mechani- 
 cally, instead of by manual labour on the hearth. The 
 cast iron is run directly from the blast furnace, through 
 a gutter, which delivers it, in a broad thin stream, into 
 an ingot mould; a similar stream of finely-divided 
 hematite or magnetic ore being supplied simultaneously 
 through another channel. In this way a porous mass, 
 known as a pig bloom, is obtained, weighing not 
 quite 1 cwt. The moulds form a ring on une circum- 
 ference of a cast-iron table, divided into 54 partitions, 
 and about 2 feet long and 8 inches deep, which rests 
 upon friction rollers, and is slowly revolved by steam 
 power, so as to bring each division in succession under 
 the channel supplying the metal and ore. The table 
 makes four revolutions per minute, and the total weight 
 of the 54 blooms is 50 cwt. At Dowlais, where 
 the process was tried experimentally, considerable diffi- 
 culty was sometimes experienced in breaking up the 
 blooms in the puddling furnace, and a Blake's rock- 
 breaker was tried, for the purpose of reducing the size 
 of the blooms before charging them. The best results 
 
 Q 
 
338 METALLURGY OF IRON. 
 
 were obtained with the use of 15 per cent, of red hema- 
 tite and 5 per cent, of coke, when an increased yield 
 of about 4 per cent, over that of the ordinary process 
 was obtained. When the amount of ore added was 
 larger the furnace worked cold, and the slag was not 
 sufficiently fluid, and the work was harder than ordinary 
 puddling. This process, though found advantageous in 
 America, on account of the saving in labour, has not 
 been adopted in this country. 
 
 According to Parry, the amount of phosphorus con- 
 tained in puddled iron is from 20 to 25 per cent, of 
 that originally present in the pig iron, and of sulphur 
 about 20 per cent. If, therefore, the iron so obtained 
 is reconverted into pig iron by fusion with carbon, 
 taking care that neither sulphur nor phosphorus is 
 re-introduced, the proportion of these substances in the 
 iron obtained from the purified metal by a "second 
 puddling will be almost inappreciable. Thus, if in 
 the first instance the mine pig contained 0*75 per cent, 
 of phosphorus, this would be reduced on the first 
 puddling to 0*15 per cent., and on the second to 0*03 
 per cent. Parry's process of double puddling is founded 
 upon the above property. The material treated is the 
 waste produced in finishing bar iron, known as crop 
 ends ; these are melted with coke in a cupola furnace, 
 differing from that ordinarily used by iron-founders 
 in having a strongly-inclined twyer, in addition to the 
 ordinary horizontal one, through which the blast is in- 
 troduced. It is, in fact, a combination of a blast furnace 
 with a refinery, and the product is very similar to that 
 obtained in refining with coke, namely, a metal of 
 low degree of carburisation, almost entirely free from 
 silicon. This is run into moulds, and afterwards 
 puddled in the usual way, giving a pure quality of 
 iron, which it is suggested may be still further im- 
 
FORGE AND MILL MACHINERY. 
 
 339 
 
 proved by repeating the fusion in the cupola, and 
 puddling a third time. The consumption of coke is 
 at the rate of about 30 or 40 per cent, of the weight 
 of the scrap iron converted. It is, of course, necessary 
 to prevent the iron taking up sulphur from the ash of 
 the coke by a proper addition of limestone or other 
 appropriate fluxes in the cupola. For this purpose, it 
 is suggested that the coke may be impregnated with 
 salt or carbonate of soda by steeping it in a solution of 
 these salts for some time before it is required for use 
 
 The rotatory puddling furnace, which was originally 
 proposed by Mr. Menelaus, and used experimentally 
 for a short time at Dowlais, when it was abandoned 
 
 Fig. 27a. Banks' s rotatory puddling furnace. 
 
 A. Half-elevation of rotatory chamber. 
 
 B. Half-section through rotatory chamber. 
 
 owing to the difficulty of obtaining a sufficiently suitable 
 and refractory material for the lining, has within the 
 last two years been much improved and perfected by 
 Mr. Banks in the United States, who has made ths 
 
 Q2 
 
340 METALLURGY OF IRON. 
 
 process a technical success. The furnace repre- 
 sented in Fig. 27a takes a charge of 600 Ibs. at one 
 heat. Fig. 27 b is a longitudinal section. In Fig. 27 a 
 the right hand half B represents a transverse section 
 through the centre of the furnace, and the left hand 
 A the elevation at the forward end. Fig. 27 c is the 
 elevation of the flue end. The furnace consists of 
 three parts, a fixed fireplace and bridge, a moveable 
 puddling chamber taking the place of the ordinary 
 
 Fig. 27J. Banks' s rotatory puddling furnace. Longitudinal section through fire- 
 place, puddling chamber, and moveable flue. 
 
 bed, and a flue which is composed of a fixed part 
 leading to the chimney and a moveable part connect- 
 ing it with the chamber. 
 
 The fireplace is of the ordinary description, with an 
 air-blast for increasing the intensity of the combus- 
 tion. The air is supplied partly through a pipe below 
 the grate, and partly through two series of small 
 twyers in the back wall at the level of the firebridge, 
 the amount being regulated by a valve in the admis- 
 
RKVERBERATORY FINERY OR PUDDLING PROCESS. 341 
 
 sion-pipe. The firebridge, which, is of cast iron 
 cooled by a current of water circulating through it, is 
 faced on one side with firebrick, and on the other by 
 a layer of fettling similar to that used in the puddling 
 chamber. The outside of the fireplace is formed by a 
 thick cast-iron ring, also cooled with water, whose 
 outer surface is cast in chill, and forms a rubbing face 
 for a similar ring on the rotating part. 
 
 Fig. 27c. Dunks s lotatoiy puddling furnace. Transverse elevation at flue end. 
 
 The puddling chamber is a cast-iron cylinder with 
 conical ends 4 ft. long by 5 ft. 3 in. greatest dia- 
 meter. It is bound with iron hoops and faced with 
 flat rings, which rub upon similar surfaces fixed in 
 the faces of the fireplace and flue. The cylindrical 
 body of the chamber is formed of cast-iron segments 
 kept together by the conical ends, and has twelve 
 radial ribs projecting internally for keeping the lining 
 or fettling in its place. At either end of the cylinder 
 is a belt turned smooth, forming the bearing surfaces 
 
342 METALLURGY OF IRON. 
 
 for the chamber upon the friction rollers which support 
 it, and in the centre is a toothed ring which receives 
 motion from a pinion driven hy a pair of small steam- 
 engines. The front conical cover has a tap-hole for 
 letting out the cinder. The moveable flue is made 
 of cast iron, lined like the puddling chamber, and 
 cooled by water. In the end is a stopper hole through 
 which the process can be watched, and the rabbling- 
 bar, or tool for tapping the slags or balling the 
 iron, can be introduced. When at work, the moveablo 
 flue is kept in position by two stays connected with 
 ratchet wheels, but it is also suspended by two 
 rods to a truck with rollers, which moves on an 
 overhead railway, so that by disconnecting the lower 
 stays it is left suspended to the truck, and may be 
 moved to one side, leaving the end of the chamber 
 open for withdrawing the ball. In . this way the 
 necessity of making a working door in the chamber 
 is avoided. The moveable piece is connected by a 
 short brick flue with the chimney-stack in the usual 
 way. The fettling or lining of the chamber is made in 
 two thicknesses : the first or initial layer consists of a 
 mixture of crushed iron ore and slacked lime brought 
 to the consistency of mortar, which is filled up to about 
 an inch above the projecting ribs. One-third of the 
 surface is covered at a time, the coating being dried 
 by a wood fire before adding a new portion. The 
 whole operation requires from 10 to 11 hours. 
 The ore should not contain more than 5 per cent, of 
 silica, and be free from combined water, which is likely 
 to crack the lining when driven off by subsequent 
 heating. About 30 cwt. of ore and 4 cwt. of lime are 
 used to form the initial lining. The fettling proper is 
 formed by melting upon the initial lining pulverized 
 
REVTCRBERATORY FINERY OR PUDDLING PROCESS. 343 
 
 iron ore, hammer- slag, and scale, in quantity sufficient 
 to form a pool in the bottom of the cylinder, into 
 which pieces of harder ore are thrown in until the 
 surface is studded with lumps projecting from 2 to 
 6 in., when it is allowed to set, and the operation is 
 repeated with the cylinder in a different position until 
 the interior is completely lined. From 2 to 2J tons of 
 ore are required for a 700-lbs. furnace, and about 
 3 tons of coal are required for the different operations 
 of drying and melting the fettling. 
 
 The steps in the operation of puddling are similar to 
 those of the ordinary process, the rotary motion of the 
 chamber being substituted for the action of the 
 puddler's rabble. The pig iron is charged through 
 the flue end upon a quantity of cinder, from 30 to 60 
 per cent, of its own weight, either in a solid or 
 melted condition. In the former case the time re- 
 quired for melting down is from 30 to 35 minutes, 
 during which period the chamber is partly rotated 
 in order to bring the charge equally under the 
 action of the flame. When the whole charge is 
 thoroughly melted, the chamber is made to revolve 
 from two to three times in a minute, for five or 
 ten minutes ; a stream of water is then injected to 
 solidify a portion of the supernatant cinder, which, as 
 the chamber turns, is carried into the bulk of molten 
 iron, and in this way a continuous action, resembling 
 that produced by the incorporation of scale and other 
 oxidized iron products in the ordinary furnaces by the 
 puddler's rabble, is kept up until the iron begins to 
 thicken, when the motion is stopped, and the fire is 
 raised until the cinder being perfectly liquefied, it is 
 run off through the tap-hole, the chamber being 
 brought into a proper position for the purpose, The 
 
jM-fcTALLURGY OF IRON. 
 
 rotation is then continued at six to eight revolutions 
 per minute until the iron begins to adhere together, 
 when the speed is reduced to two revolutions, and the 
 ball commences to form. If any loose pieces are 
 found, the puddler moves them to one side, and by 
 turning the furnace partially, so as to tumble the 
 main mass over them, they are made to coalesce 
 with it. The fore end of the ball is solidified by a 
 few blows from a tool introduced through the stopper- 
 hole. The flue piece is then moved to one side, leaving 
 the end of the chamber open, and the ball is removed 
 by a fork worked by a crane, and carried to the 
 squeezer, where it is shingled, and afterwards rolled to 
 a puddled bar in the usual way. The time of working 
 one charge lasts from an hour to an hour and a half, 
 according as the pig metal may be white or grey. 
 From eight to ten charges may be made before the 
 fettling requires to be repaired. The average con- 
 sumption of fettling materials, ore scrap, and forge 
 cinder, is about 12 cwt. per ton of puddled bars pro- 
 duced. The coal used is 22 cwt., some of which may 
 be saved by melting the metal in a cupola instead of 
 melting it in the furnace. A special form of squeezer 
 is used, consisting of two corrugated rolls placed hori- 
 zontally in the same plane, moving in the same direc- 
 tion, making 15 or 20 revolutions per minute. Above 
 these is placed a large excentric, or cam, geared to the 
 rolls, and moving in the same direction with the same 
 circumferential speed ; at the side of the frame is a 
 horizontal steam-hammer, which hammers the end of 
 the bloom as it is being rotated. When the bloom is 
 sufficiently squeezed, which is dona in two revolutions 
 of the cam, it is turned out in the form of a cylinder 
 with squeezed ends, and can be removed to the 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 345 
 
 reheating furnace at once. Owing to the large sur- 
 face of the lining and the exclusion of air, the re- 
 moval of the carbon silicon, and other foreign matters 
 in the pig iron is effected entirely by the peroxide of 
 iron in the fettling with the reduction of a correspond- 
 ing portion of iron which goes to increase the weight 
 of the ball, so that the amount of puddled bar produced 
 is, under favourable conditions, somewhat greater than 
 that of the pig metal charged. Mr. Snelus, in his 
 report to the Iron and Steel Association, points out 
 that the yield from white pig iron in the Danks's 
 furnace is found to be inferior to that from grey, there 
 being a difference of from 1 to 1J cwts. in the quan- 
 tity required to make a ton of puddled bars, in favour 
 of grey over white forge pig. When the puddling 
 had to be done by hand, the use of white pig saved 
 a great deal of labour ; but, with the adoption of 
 machinery, the above advantage, in addition to the 
 higher quality of the product, will probably render it 
 more economical to make forge pig moderately grey 
 and silicious rather than white, in spite of the increased 
 consumption of fuel in the blast furnace required for 
 its production The working power of the Danks' 
 furnace is about four times that of the ordinary 
 single puddling furnace, or rather twelve of the former 
 may be taken as equivalent to fifty of the latter. 
 
 A somewhat similar furnace has been introduced -by 
 Mr. Spencer at Hartlepool. Instead of being a cylin- 
 der, the revolving chamber is a long box of square 
 section, measuring 9 ft. in length by 4f ft. in the side. 
 The fettling material is the cinder known as best tap ; 
 it is obtained from reheating furnaces which have iron 
 bottoms covered with purple ore, instead of the sand 
 bottom formerly used. This cinder is very free from 
 
 Q3 
 
346 METALLURGY OF IRON. 
 
 silica and phosphorus, and can be easily melted. It is 
 cast into troughs or divisions formed by projecting ribs 
 on the sides of the chamber, and built in blocks pro- 
 perly moulded, the whole being cemented together by 
 melted tap into a smooth and regular form. The 
 repairs are done by running in the same material 
 melted from a ladle through a spout to the place where 
 it may be required. In an early form of the furnace 
 the chamber was placed with its sides skew to the axis 
 of rotation of the chamber, but latterly the rectangular 
 form has been adopted in preference. In other respects 
 the working of this furnace is similar to that of 
 Danks's, but as the cast iron is introduced in a melted 
 state, the heat is worked off in less time. 
 
 Another form of rotating furnace has been recently 
 introduced by Mr. Siemens. It resembles Danks's, 
 but in the form of the revolving chamber differs 
 from it in many important particulars, especially 
 in the fettling, the aluminous brown iron ore known 
 as Bauxite being employed for that purpose. This 
 contains when calcined from 44 to 68 per cent, of 
 alumina, 28 to 52 per cent, of peroxide of iron, and 
 3 or 4 per cent, of silica ; it is rendered coherent by a 
 small addition of clay or silicate of soda, and about 
 6 per cent, of graphite is added to the mass, which 
 renders it practically infusible by reducing the per- 
 oxide of iron to the metallic state. This material has 
 the advantage of becoming converted under the action 
 of strong and continued heat to a solid mass of emery 
 of intense hardness, besides being infusible, and there- 
 fore capable of resisting the mechanical scouring of 
 the charge as well as great heat and chemical action. 
 The fireplace is of the ordinary regenerative form for 
 burning intensely heated gases. The flame enters the 
 
RE\ ERBERATORY FINERY OR PUDDLING PROCESS 347 
 
 chamber, by a flue divided by a midway partition- wall, 
 with sufficient velocity to traverse its whole length 
 and return through the other division on its way to 
 the regenerators. The moveable flue of Danks's furnace 
 is replaced by an ordinary sliding door lifted by a 
 chain and counterpoise. The chamber, which is about 
 7J ft. in diameter, and 9 ft. long, is provided with two 
 trains of wheel- gearing, by which it can be turned 
 either very slowly, from 4 to 5 revolutions per 
 hour, or more rapidly, from 60 to 80 revolutions 
 in the same time. The Bauxite lining is about 7 in. 
 thick. There is a tap-hole on the working end for 
 discharging the slag into a pit below, where it is 
 received in tubs mounted on wheels for facility of 
 removal. The object of this furnace is not for pud- 
 dling, but for the production of malleable iron or steel 
 directly from the ore. It is worked as follows. The 
 ore is broken up into fragments of the size of peas or 
 beans ; to it is added lime or other fluxes, so as to form 
 a basic fluid slag with only a little protoxide of iron. 
 With hematite or eilicious ore aluminous ore may be 
 used, and also manganesiferous ores with advantage , 
 About 20 cwt. of materials are charged, and the 
 furnace is slowly revolved for 40 minutes, when the 
 contents will be raised to a bright red heat. From 
 5 to 6 cwt. of small coal is now added, and the rotative 
 velocity is increased. A rapid reaction takes place : 
 the peroxide of iron being reduced to the magnetic 
 state, begins to fuse, and at the same time the carbon 
 precipitates metallic iron, while the fluxes take up the 
 silica of the ore forming a fluid slag. The slow action 
 is again employed, the mass being turned over and 
 over, continually presenting new surfaces to the heated 
 lining and flame within the rotator. During thia 
 
348 METALLURGY OF IRON. 
 
 period, carbonic oxide gas is evolved by the action of 
 the ore on the carbon, and heated air alone is intro- 
 duced to effect its combustion, the gas from the gas- 
 producers being almost shut off. When the reduction 
 of the ore is nearly complete, the tap-hole is brought 
 into proper position ; the rotatory motion is stopped, 
 and the cinder is tapped off; afterwards the quick 
 speed is put on, whereby the loose masses of iron are 
 rapidly collected into two or three balls. These are 
 taken out and shingled in the ordinary way ; the 
 furnace is tapped again, and is ready for another 
 charge. The time cf working one charge rarely 
 exceeds two hours ; and at 10 cwt. per charge the 
 furnace is capable of yielding 5 tons of puddled bars 
 in twenty-four hours. If anthracite or hard coke be 
 used for reduction, it should be crushed much finer 
 than coal or lignite, while wood is to be used in larger 
 pieces, the object being to consume the whole of the 
 reducing material less its ash, which is taken up by 
 the fluxes to form part of the slag. If it is intended 
 to form cast steel instead of iron, the balls may be 
 transferred without shingling to the bath of the 
 Siemens' steel melting furnace. This process, which is 
 still in the experimental state, promises to be of great 
 value in countries where, for want of good fuel, blast 
 furnaces cannot be erected. The fuel used being 
 divided, part being burnt in the gas-producers, only 
 that required for the reduction of the oxides of iron 
 being brought in contact with the charge, there is 
 so much less ash to be fluxed, and proportionately less 
 chance of the iron being contaminated with impurities 
 than when the whole amount is consumed in contact 
 with the charge, as in the blast furnace. The great 
 source of economy of fuel is however to be looked for in 
 
REVERBERATORY FINERY OR PUDDLING PROCESS. 349 
 
 the fact that whereas blast-furnace gases contain large 
 quantities of carbonic oxide, and are given off at 350, 
 the gas of the rotator is essentially carbonic acid, 
 which passes from the regenerator to the chimney at 
 about 175. The process, although originally designed 
 for use with pure rich ores, gives iron of good quality 
 with low-class ores. 
 
 In the latter case the loss of iron is considerable ; 
 part of it being used as flux in order to prevent the 
 reduction of phosphorus, as in the Catalan process. 
 
 CHAPTER XYI. 
 
 FORGE AND MILL MACHINERY. 
 
 THE machines used in the compression and welding of 
 the rough balls of malleable iron into blooms are of two 
 different kinds, namely, hammers and squeezers, thf> 
 former acting by percussion, and the latter by compres- 
 sion. In addition to these, it is usual in puddling forges to 
 reduce the blooms obtained by hammering or squeezing 
 to rough bars by passing them at the same heat through 
 a rolling mill. 
 
 By the term forge is usually understood those portions 
 of iron works which are intended for the production of 
 puddled blooms or rough bars, including the puddling 
 furnaces, shingling machines, and puddling rolls. The 
 remaining portion of the works, where the rough bars 
 are reheated and reduced to finished or merchant iron, 
 is known as the mill, and includes the reheating or 
 balling furnaces, and the various kinds of rolling mills 
 and finishing machinery employed in the production 
 of plates, bars, and other merchantable products. 
 
350 METALLURGY OF IRON. 
 
 The oldest and simplest class of machines used in 
 forging blooms are lever hammers. These are of two 
 classes, namely, tilt hammers, where the axis is between 
 the point of application of the cam and the head, and 
 helves, or lift hammers. In the former, the head is placed 
 near the end of the lenger arm, while the cam acts at 
 the end or tail of the shorter one. In lifting hammers, 
 or helves, the hammer block and the lifting cam are 
 placed on the same side of the fulcrum. These, again, are 
 of two kinds the tenant, nose,, or frontal helve, where 
 the cam acts upon a tongue immediately in front of the 
 hammer-block, corresponding to a lever of the second 
 order, and the belly helve, which has the cam shaft 
 placed below the floor, and acting about midway 
 between the fulcrum and the head, forms a lever of 
 the third order, so that the anvil is free on three sides. 
 In all of the preceding varieties the axis of rotation 
 of the cam ring is placed at right angles to the line 
 of the hammer. Besides these, there is another old- 
 fashioned form known in Germany as the pitch-up 
 hammer, which differs from the belly helve in having 
 the line of rotation of the axis parallel to that of the 
 hammer stem. 
 
 Tilt hammers are usually made of small sizes, the 
 head of the heaviest weighing about 5 cwt. ; they are 
 driven at considerable speed, and are used rather in 
 drawing out bars, making spikes, and finishing work 
 generally, than for shingling blooms in the first state. 
 The shaft or stem is made of one or more beams of 
 straight-grained springy wood, according to size, 
 hooped together with rings of wrought iron. The 
 pivots are either attached to a broad central hoop, or 
 are mortised through the shaft. The head is usually 
 shaped like that of a large sledge hammer. 
 
FORGE AND MILL MACHINERY. 351 
 
 Helve hammers, such as were formerly in general 
 use in puddling forges, have been made of all weights 
 up to 10 tons. The usual sizes are between 30 cwt. 
 and 5 tons; they make between 70 and 100 strokes 
 per minute, with lift of between 16 and 20 inches. 
 In Staffordshire shingling helves are used from 5 to 6 
 tons in weight, while those for blooming piles for finished 
 iron average from 7 to 8 tons. Seen in plan, the helve 
 is a ( shaped mass of cast iron ; the cross arms form 
 the bearing, the hammer face of wrought iron being- 
 keyed into a conical socket at the opposite end for con- 
 venience of renewal. The use of the long heavy cross 
 arm for the pivots is necessary to prevent the mass 
 of the helve from shifting in its bearings, which are 
 open. The height of the lift may be regulated by the 
 amount of projection given to the tongue or wiper 
 acted upon by the cam. In all cases it is necessary for 
 the preservation of the machine never to allow the 
 hammer to fall directly upon the anvil. For this 
 purpose, when not in use, a stop or gag of iron or 
 wood is placed between the head and the anvil, which 
 lifts the shaft just clear of the action of the cam. By 
 placing a piece of iron on the tongue of sufficient 
 thickness to allow the cam to come in contact with it, 
 the hammer is lifted, and the removal of the stop is 
 again brought into working order. 
 
 The foundations of forge hammers require to be very 
 massive, in order to withstand the violent shaking to 
 which they are subjected. Large, squared balks 01 
 timber upon a bed of stone masonry or concrete are 
 usually employed, piled crossways on end for carry- 
 ing the framings of the hammer and cam-ring shaft 
 The anvil is a block of cast iron several times the 
 weight of the hammer, standing independently, so that 
 
352 METALLURGY OF IRON. 
 
 its vibration may not be transmitted to the bearings of 
 the fixed parts. 
 
 Fig. 28 is a longitudinal elevation of a frontal helve 
 weighing 3J tons, adapted for a forge driven by 
 
 Fig. 28. 70-cwt. Shingling helve. 
 
 tvater power. The following are the weights of the 
 
 principal parts : 
 
 "Weight of helve 70 cwt. 
 
 Anvil 150 
 
 Cam ring 125 
 
 Fly wheel 120 
 
 Main shaft 90 
 
 The hammer is lifted five times in each revolution of 
 the shaft ; the height of the lift is 16 inches. A water 
 wheel of 25-horse power is required to drive it. 
 
 In water-power forges with small hammers of from 
 5 to 9 cwt. a wooden spring beam is often used for 
 augmenting the force of the blow by the violent velo- 
 city of descent. This construction was in general use 
 in Europe before the introduction of steam power, and 
 numerous instances of it are still to be found in Sweden. 
 
 Where water power is used, especially in small forges, 
 
FORGE AND MILL MACHINERY. 353 
 
 each hammer is generally driven by its own wheel, the 
 axis of the latter moving the cam ring directly without 
 intermediate gearing. In forges worked by steam power, 
 where several machines are driven by a single engine, 
 the hammers or helves are connected by gearing 
 wheels to the driving main shaft, being usually placed 
 as near to the puddling or heating furnaces as poss'ble. 
 
 The working faces of both hammers and anvils are 
 subject to great wear, and require to be replaced at 
 short intervals. They may be made to last for a con- 
 siderably longer time when kept cool by a current of 
 water circulating through them. This method was intro- 
 duced by Condie, the inventor of the water twyer, but 
 does not appear to have been adopted to any great extent 
 
 In erecting new forges at the present time, direct- 
 acting steam hammers are generally preferred, instead 
 of the helve, for shingling and balling purposes. This 
 machine, as is well known, was introduced by Nasmyth 
 in 1842, and still maintains its original construction 
 in most essential particulars, although it has been 
 largely modified in details, both by the inventor and 
 other makers. It consists essentially of an inverted 
 cylinder, vertical, high-pressure engine, supported by 
 an arched or inverted Y-shaped framing, formed of two 
 standards of cast iron. The piston rod passes through 
 the lower cylinder cover, and is directly connected with 
 a heavy hammer block or tup, which moves vertically 
 between guides attached to the inner faces of the 
 standards. In the single-acting form, the steam is 
 employed only for lifting the hammer block, which 
 delivers its blow with the impact due to the fall alone ; 
 but in the double-acting or top steam hammer, the 
 force of the blow is increased by allowing the steam 
 to act on the upper surface and accelerate the speed of 
 
354 METALLURGY OF IRON. 
 
 descent. A great advantage possessed by the steam 
 hammer consists in the power of regulating the force of 
 the blow according to the necessity of the work, as the 
 block may be stopped at any portion of its stroke by 
 cushioning or checking the exit of the exhaust steam. 
 In shingling blooms, for instance, at the commence- 
 ment, it may sometimes be advisable to consolidate the 
 ball by short, light strokes, afterwards increasing the 
 force by working with a longer fall as the iron becomes 
 harder and more compact. This cannot be done with 
 a helve hammer, whose height of fall, and consequent 
 impact, is invariable. The weight of the hammer block 
 varies with the nature of the work. In puddling 
 forges for shingling ordinary- sized blooms, hammers 
 of from 30 to 60 cwt. are commonly used. One 
 of 50 cwt. is sufficient to do the work of twelve 
 furnaces, and may be worked by the waste heat of one 
 >r two reheating furnaces. In the blooming and 
 forging of heavy masses, such as piles for armour 
 plates, marine engine- crank shafts, and large, irregular 
 forgings for ships, as well as in steel works, very much 
 larger sizes are employed, the weight of the block 
 ranging from 5 to 50 tons. Hammers of the largest 
 size are usually only made single-acting; the use of 
 steam above the piston being rarely resorted to when 
 the weight is more than 12 or 15 tons. 
 
 Fig. 29 is a side elevation of a double-acting steam 
 hammer constructed by Thwaites and Carbutt, of 
 Bradford; it is reduced from a drawing kindly fur- 
 nished by the makers. The hammer block or tup, 
 weighing 8 tons, is attached by a thin cylindrical rod, as 
 in the original Nasmyth hammer, to the steam piston, 
 which is 28 inches in diameter, and makes a stroke of 
 ft feet in length. The arrangements for admitting and 
 
FORGE AND MILL MACHINERY. 
 
 355 
 
 exhausting the steam above and below the piston are 
 similar to those of an ordinary high-pressure steam 
 engine. The slide valve is of a tubular form, and 
 balanced against the steam pressure in the valve chest, 
 
 Fig. 29. Thwaites and Carbutt's 8-ton double-acting steam hammer. 
 
 so that it may be readily moved by hand by means 
 of the lever, c. d is the handle which moves the steam 
 admission or regulator valve. The length of the up 
 stroke is determined by the tappet, a, on the hammer 
 block, which strikes against the arm of the bent lever, 
 b t and moves the slide valve, so as to open the exhaust 
 passage, which allows the steam from below the piston 
 to escape into the atmosphere at e. The principal 
 aammerman stands on the raised platform, /, having 
 
356 METALLURGY OF ITION 
 
 the valve levers close at hand, at the same time com- 
 manding an uninterrupted view of the work in process 
 of forging on the anvil. 
 
 In small hammers below 12 or 15 cwt., such as are 
 used for heavy smithing, and instead of the old tilt 
 hammer in steel works, the framing is often reduced to 
 a single standard overhanging its base, giving a clear 
 working space on three sides of the anvil. Wrought- 
 iron standards have lately been introduced. 
 
 Another type of steam hammer is that having a 
 piston with two unequal surfaces exposed to the action 
 of the steam, by employing a very thick piston rod. 
 The lower or smaller surface is constantly in connection 
 with the steam by an open port, while it is only 
 allowed access to the larger face during the driving 
 portion of the stroke. 
 
 Condie's hammer is distinguished by the peculiarity 
 of having a fixed piston and a movable cylinder, the 
 latter being cast in o**~ with the hammer block. The 
 piston is suspended uy a rod connected with a ball-and- 
 socket joint to the top cross bar of the framing. 
 
 In many modern hammers parallel guides below the 
 cylinder are not used, the piston being prevented from 
 turning by using a rod of angular or irregular section, 
 such as a square or a cylinder, with a portion of it>- 
 surface planed down to a flat face, passing through a 
 stuffing box of a similar figure. 
 
 The anvils of steam hammers require to be of great 
 weight, and so arranged as to stand completely clear 
 of the ground carrying the framing. For moderate 
 sizes, a convenient foundation may be made of squared 
 timber, placed on end above a bed of broken cinder 
 beaten hard, or concrete ; but in the monster hammers 
 used in steel works, the anvil and its foundation are built 
 
FORGE AND MILL MACHINERY. 357 
 
 up of masses of cast iron. Thus in Krupp's 50-ton 
 hammer, which has a maximum lift of 10 feet, the 
 anvil, weighing 185 tons, is carried upon a substructure 
 of cast iron, formed of eight blocks, weighing from 1 25 
 to 135 tons each. 
 
 Ramsbottom's horizontal hammer consists of two 
 blocks or rams of great weight, supported by friction 
 wheels, travelling on a short level railway, which 
 can be drawn together or separated by a vertical 
 
 Fig. 30. Rarosbottom's duplex steam hammer. 
 
 steam engine acting upon a system of link rods. There 
 is no anvil. The mass to be hammered is supported 
 upon a carriage on a central platform, and is struck 
 simultaneously on either side by the meeting of the 
 rams. The general construction of the machine is 
 shown in Fig. 30. a a' are the two hammer blocks, which 
 are moved by the piston, b, of an ordinary double- 
 acting steam engine by means of the connecting rods, 
 c c. d is the slide valve, and e the admission valve, 
 both of which can be worked by hand levers. The 
 ingot, in process of hammering, is fixed upright in a 
 cast iron carrier, /, united by a link rod with a 
 
358 METALLURGY OF IRON. 
 
 lever carrying a counterbalance weight at the oppo- 
 site end. A hand lever, g, attached to the same 
 shaft, serves to raise or lower the ingot/ so as to bring 
 a fresh portion of its length within the range of the 
 hammers. 
 
 In the newest form of this hammer, the blocks or 
 tups, weighing 30 tons each, are driven directly by a 
 pair of horizontal steam engines, without the use of 
 link rods. Each tup is driven independently by its 
 own piston, but a provision is made for equalising the 
 motion by a projecting arm carrying a nut, which 
 travels on a long screw running parallel with the line 
 of motion, whereby, in the event of one mass travelling 
 faster than the other, the screw acts as an auxiliary 
 driving power to the slower- going one, and brings it 
 up to the speed of the other, so that both may strike 
 the ingot at the same moment. 
 
 Another class of hammer sometimes used for small 
 work combines the piston and cylinder with the 
 method of lifting by cams. The hammer resembles 
 an ordinary stamp head, moving vertically between 
 guides by means of a rotating shaft armed with cams. 
 The upper part of the rod carries a piston, which 
 compresses air in the cylinder during the up stroke, 
 the power so expended being given out by the ex- 
 pansion of the air during the down stroke, giving an 
 increased force to the blow, similarly to that obtained 
 when steam is used on the top of the piston in an 
 ordinary steam hammer, 
 
 In all cases the striking faces of hammers and anvils 
 are made removable, and are attached by dovetailed 
 wedges, fitting into a corresponding groove on the 
 blocks. Besides the plain faces for ordinary forging, 
 
FORGE AND MILL MACHINERY. 
 
 359 
 
 swages and moulds are often used, as, for example, in 
 drawing round bars, or swaging up spherical cast- steel 
 shot. 
 
 Squeezers. In these machines the welding of the 
 ball is effected by pressure applied without impact. 
 They are of two kinds, namely, lever and rotary 
 squeezers. In the former class, a lever of cast iron 
 is made to oscillate about a fixed centre by means of 
 a crank and connecting rod attached to the end of one 
 
 Fig. 31. Double squeezer. Dowlais (Truran). 
 
 arm. The opposite arm carries a jaw or plate of cast 
 iron, which may be either flat or serrated with parallel 
 triangular teeth, working against a corresponding fixed 
 jaw, placed in the position occupied by the anvil in an 
 ordinary lever hammer. The ball is introduced between 
 the jaws of the machine at the widest part, and is 
 pushed backwards as its thickness diminishes ; the 
 ends are compressed by placing the bloom on end 
 between the jaws at the greatest opening. Fig. 31 
 is a longitudinal elevation of a double squeezer, i.e., 
 having a pair of working faces in connection with 
 either arm of the lever, in use at Dowlais, in South 
 Wales. 
 
 The rotary squeezer consists of a cylinder, whose 
 
360 METALLURGY OF IRON. 
 
 surface is studded with, blunt triangular teeth, having 
 'ts axis of rotation placed either horizontally or verti 
 cally within a fixed circular casing of cast iron similarly 
 roughened, and forming from one-half to three-quarters 
 of an entire circle. The axis of the moving cylinder is 
 placed eccentrically with regard to that of the case, 
 so that although their surfaces are parallel, the distance 
 between them diminishes in the direction of the rotation. 
 The ball is entered at the widest part, and being carried 
 forward by the action of the cylinder, is gradually 
 reduced in thickness by compression against the surface 
 of the casing, and emerges at the smaller aperture 
 ready for the rolling mill. As there is no means of 
 regulating the distance between the two pressing 
 surfaces, it is necessary to work with balls of a 
 tolerably regular figure, and as much as possible of 
 a uniform size. In Belgium one of these machines 
 is considered able to do the shingling for fifty puddling 
 furnaces. The speed should not exceed twelve revolu- 
 tions per minute. 
 
 Sometimes squeezers are arranged to be driven by 
 a steam engine attached to the outer arm of the lever, 
 but more generally they are connected to the driving 
 shaft of a rolling mill, as, for instance, that employed 
 in rolling blooms into puddled bars. 
 
 In the manipulation of very heavy masses, such as 
 in welding the piles for large plates, forging of steel 
 ingots, &c., where a powerful compressing force is re- 
 quired, hydraulic squeezers, or forging presses, may 
 be used with advantage. As an example of this class 
 of machine may be mentioned HaswelFs hydraulic 
 hammer. It consists of a large vertical cylinder 
 hydraulic press, with its ram acting downwards against 
 a table, representing the anvil. The ram is lifted bj? 
 
FORGE AND MILL MACHINERY. 361 
 
 the piston of a smaller press, with which it is connected 
 by cross arms and side rods placed overhead. The water 
 driven out of the large cylinder as the ram rises is 
 returned to a vertical cylinder or accumulator, also 
 containing a piston, to whose upper face steam can be 
 admitted. This arrangement is used to obtain speed 
 in moving the ram when not actually working, or 
 while the resistance of the pile is inconsiderable. When 
 greater pressure is wanted, a valve, connecting the 
 press with the speed piston is shut, and the ordinary 
 hydraulic press pumps, which are driven by a large 
 direct- acting horizontal steam engine, are brought into 
 action. In this way, by reserving the press pump 
 for the heavier portion of the work, the machine may 
 be driven nearly as quickly as a steam hammer, and 
 jwing to the substitution of an intense slow pressure, 
 for the percussive impact of the hammer, massive 
 foundations are not required. 
 
 Rolling Mills. These are now generally used in the 
 production of finished or merchant iron, in preference 
 to the hammer, which is mainly confined to the old 
 open fire forges of Sweden and Germany. In its 
 simplest form, a rolling mill consists of two cast-iron 
 cylinders, placed with their axes horizontally one above 
 the other, and connected by spur gearing, so as to revolve 
 at the same velocity when set in motion. The surface 
 of the rolls may be either smooth, as is the case in plate 
 mills, or grooved into various patterns in those used 
 for the production of merchant bars. In the latter case 
 the groove on either roll corresponds to half the section, 
 the two together forming an aperture or rotating die 
 corresponding to the shape required. The reduction 
 in size of the bloom is effected by regulating the ver- 
 tical distance between the two rolls, by the use of 
 
362 
 
 METALLURGY OP IROX. 
 
 grooves diminishing regularly in size, or by a combina- 
 tion of both methods. Fig. 32 is a generalised elevation 
 of a single pair of rolls, with both angular and flat 
 
 Fig. 32. Rolling mill. 
 
 grooves, a combination which is not actually used in 
 practice, but has been adopted here to avoid the employ- 
 ment of a second figure. 
 
 The journals or necks of the rolls run on brass bear- 
 ings, which are supported in strong cast-iron frames 
 or housings. In Fig. 32 one of these is shown in front 
 elevation, and the other in section. The motion is 
 usually communicated by the lower roll, and transmitted 
 to the upper one by a pair of spur- gearing wheels, 
 which are placed either on the rolls themselves, as in 
 the figure, or are carried by a special pair of housings. 
 When two or more pairs of rolls are connected into 
 
FORGE AND MILL MACHINERY. 363 
 
 one system by couplings, and driven by the same 
 motor, they are called a mill or train. The first pair of 
 the train are generally known as the roughing rolls, 
 and the following ones as the finishing rolls. The 
 latter have smooth surfaces, but the former, especially 
 in puddle-bar trains, are often roughened, in order to 
 get a better hold on the bloom at its entry. The first 
 pair are also called the blooming rolls, as the work done 
 by them is chiefly confined to welding the bars com- 
 posing the pile, while the finishing pair is mainly 
 employed to draw out the pile so compacted. 
 
 As the direction of rotation of the rolls is constant 
 under ordinary circumstances, it is necessary, after the 
 bar has passed through one groove, to return it by 
 lifting it over the top roll, in order to bring it into 
 position to pass through the next smaller one, and so 
 on in succession. This may be easily done with blooms 
 of small size, but is attended with considerable difficulty 
 when it is required to handle large masses of iron, and 
 in any case gives rise to a certain loss of time, and con- 
 sequent waste of iron by scaling, from exposure to the 
 atmosphere in a highly heated condition for a longer 
 time than is absolutely required. Various contrivances 
 have been introduced in order to roll at greater speed ; 
 the most approved principle being the use of two or 
 more pairs compounded into one, as, for example, placing 
 two or three pairs in advance of each other, or passing 
 the bloom alternately through the grooves of two mills 
 moving in opposite directions ; by receiving the bar 
 on a carriage which is rapidly driven from one to the 
 other by steam power ; or finally, by the use of a com- 
 bination of three rolls placed one above another in the 
 same housing, forming the so-called three-high frai'i, 
 which is driven from the middle, the central roll 
 
 R2 
 
364 METALLURGY OF IRON. 
 
 gearing forward with the lower, and back with the 
 upper one, or the reverse, so that the bar, instead of 
 being rolled only one way, is passed backwards and 
 forwards by entering it between the grooves of the 
 middle and upper and middle and lower rolls alter- 
 nately. 
 
 Yery heavy mills, such as are used for armour 
 plates, require to be reversed at each passage of the 
 pile ; this can be the more readily done as they are 
 driven at a comparatively low speed. The transmis- 
 sion of the power in rolling mills, especially those of 
 large size, is usually effected by toothed gearing. Smaller 
 trains are sometimes driven by straps, an arrangement 
 which may be conveniently adopted when each mill 
 has a separate engine. As the rolls, when at work, 
 are subjected to sudden and great variations in torsional 
 strain, it is customary to make the couplings uniting 
 the different members of the train of less resisting 
 power than the necks of the rolls, the joints being 
 arranged at the same time so as to allow a certain 
 amount of independent motion. The arrangement 
 usually adopted for this purpose is shown in Fig. 32, 
 where the bottom roll is supposed to be connected with 
 that of another pair in the same plane on the right-hand 
 side. The necks are continued beyond their bearings for a 
 short distance, but with a smaller diameter, the section 
 being further reduced by four concave grooves or flutes, 
 as shown in the end view at a. These are united by a 
 loose piece of similar form, known as the breaking 
 shaft or spindle, c b, which is secured by two loose 
 collars, c c, overlapping the joints. The collars are pre- 
 vented from slipping by four wooden stops placed on the 
 flutes of the intermediate shaft, and secured by leather 
 straps. In the event of the rolls being brought -up 
 
FORGE AND MILL MACHINERY. 365 
 
 suddenly by the resistance of the pile, the strain is 
 taken by the breaking shaft, which, being the weakest 
 part of the train, gives way, and saves the rolls from 
 fracture. In some instances the breaking shaft is 
 further reduced in area by making a deep semicircular 
 groove round it in the middle. 
 
 In rolling bars of small section, which on account 
 of their flexibility are liable to be bent and distorted, it 
 is necessary to keep the end straight in entering the 
 grooves. For this purpose it is usual to attach parallel 
 guides with plain jaws or friction rollers to the tables 
 or aprons of such mills, which are then known as guide 
 mills or trains. 
 
 In compound mills with three rolls, the lifting of 
 large piles from the lower to the upper level is attended 
 with considerable labour, unless it be done by special 
 mechanical appliances. The usual method adopted is 
 to make the feed plates or tables movable upon 
 vertical guides, suspending them so as to travel freely 
 by counterbalance weights passing over guide pulleys. 
 The lifting may be effected either by a vibrating lever 
 receiving motion from a rotating shaft ; or more simply 
 by a single-acting steam or water-pressure engine 
 placed above the rolls, and connected to the tables by 
 a cross bar and side rods. The pile, after passing a 
 groove in the lower part, is lifted by the action of the 
 steam or other mechanism employed, and after return- 
 ing through the upper one, drops the table by its 
 unbalanced weight to the lower level, and so on, rising 
 and falling alternately, until the section is sufficiently 
 reduced. 
 
 The same kind of arrangement may also be used 
 in heavy plate mills. The pile, after passing between 
 wie rolls, need only be deposited on the top of the upper 
 
366 
 
 METALLURGY OF IRON. 
 
 one, as the friction between the two surfaces due to 
 the weight will be sufficient to return the pile to the 
 former position, taking advantage of the fact that the 
 surface above the horizontal median plane of the roll 
 travels in the reverse direction to that below it. 
 
 The set, or distance between the top and bottom 
 rolls, is adjusted by means of screws (dd' t Fig. 32) act-- 
 ing, either directly or by a cross bar, upon the bearings 
 of the frames. Each screw is provided with a graduated 
 head, in order that in altering the level, either end of the 
 roll may be shifted equally. In rolling bars of irregular 
 section, such as rails, for instance, the adjustment is only 
 necessary in order to bring out the finished product to 
 the proper weight, and, when once made, no alteration 
 
 7 =r ff v ,5 9 4. 
 
 Fig. 33. Rail mill roughing rolls. 
 
 Fig. 34. Rail mill finishing rolls. 
 
 IB necessary as long as the mill is kept on the same 
 work, the progressive reduction in the section of the 
 
FORGE ANO MILL MACHINERY. 367 
 
 pile being effected by passing it through grooves of 
 continually diminishing area. In order to prevent 
 lamination between the bars composing the pile, and 
 to render the welding as uniform as possible, it is 
 passed through with the joints flat and edgeways alter- 
 nately, in the manner indicated by the horizontal and 
 vertical lines in Figs. 33, 34, which represent the sec- 
 tion of both blooming and finishing rolls in a mill 
 making double-headed rails. The numbers in the 
 grooves refer to the order in which they are used. 
 
 In plate mills which have no grooves the distance 
 between the rolls must be diminished each time that 
 the pile is passed through. The top roll must also be 
 supported in order to prevent its falling upon the lower 
 one when it is no longer kept up by the pile. This is 
 usually done by carrying the lower bearing of the top 
 roll on a vertical forked rod, whose lower end is in 
 connection with a counterbalance weight sufficient to 
 prevent the roll from falling. 
 
 Great accuracy may be obtained in the adjustment 
 of the rolls by attaching spur wheels to the heads of 
 the setting screws, which may then be moved through 
 equal spaces by a third wheel placed between them. In 
 Ramsbottom's system of adjustment, adopted at Crewe, 
 the shaft of the central pinion carries a double spiral 
 barrel with two chains, one of which, passing over 
 guide pulleys, is connected with the ram of a water- 
 pressure engine, and the other coiling in the opposite 
 direction with a counterpoise weight. The rolls are 
 brought together by the pull of the chain from tho 
 engine, and separated by the counterpoise acting in a 
 similar manner upon the other chain. 
 
 Compound or universal rolling mills consist of a 
 combination of a vertical with an ordinary horizontal 
 
368 METALLURGY OF IRON. 
 
 pair of plain rolls, so that tlie pile may be compressed 
 equally in both directions, edgeways and flatways, at 
 once. A combination of this kind, known as While's 
 mill, has been advantageously adopted for blooming 
 rail piles in South Wales. The horizontal rolls are 
 driven in the usual way from below, the vertical pair 
 being connected with them by an intermediate shaft, 
 carrying a mitre-wheel gearing into a wheel upon one 
 of the vertical rolls. The machine is driven at a very 
 low speed, making only five revolutions per minute, so 
 that the pile is subjected to a powerful and long-con- 
 tinued pressure, as compared with the usual system of 
 blooming in the first grooves of the roughing pair in 
 an ordinary train, making from 80 to 100 revolutions 
 per minute. Mills of this class may also be used in 
 the production of bars of plain rectangular sections of 
 a great variety of dimensions by simple adjustment 
 of the rolls, instead of requiring a special pair of 
 grooves for each size, as is ordinarily the case. 
 
 Fig. 35 represents the arrangement of the rolls 
 and methods of adjustment in one of the earlier forms 
 of universal mill. In order to simplify the drawing, 
 the whole of the driving mechanism is omitted. The 
 vertical rolls are adjusted by the central sliding pinion 
 on either side, which acts on the setting screws. The 
 bearings are supported upon horizontal guide bars 
 placed between the housings. In the newer forms 
 of this mill only one of the vertical rolls is made 
 movable. 
 
 In rolling taper iron, such as the tongues of rail- 
 way switches, the setting screws are provided with 
 lifting gear, so that the distance between the rolls may 
 be continually and uniformly varied during the final 
 passage of the bars. In the first instance, the rolls are 
 
FOHGE AND MILL MACHINERY. 
 
 369 
 
 screwed down to the proper distance for producing the 
 thinnest section required, and the pressure is then 
 relieved either by a train of gearing wheels, working 
 pinions on the heads of the screws, or by allowing the 
 
 Fig. 35. Universal rolling mill. 
 
 upward pressure of the iron passing through the mill 
 to lift the roll. In the latter plan, in use at the 
 Mersey Steel and Iron Works, the pressure is exerted 
 against a solid plunger working in a cylinder filled 
 with water, and provided with a small discharge 
 passage, stopped by a conical plug valve. As long as 
 the valve is closed the water within the cylinder, from 
 
 R3 
 
370 METALLURGY OF IRON. 
 
 its incompressibility, acts like a solid body, and keeps 
 the rolls together ; but when the passage is opened, the 
 pressure from below drives the plunger upwards and 
 expels the water, thereby relieving the bearings of the 
 top roll, which is then free to rise, the rate of its 
 upward motion being regulated by the aperture pre- 
 sented for the efflux of water from the cylinder. 
 
 The finishing rolls of plate mills are cast with 
 strongly-chilled surfaces, which are afterwards turned 
 and polished, the necks and other portions being 
 formed in sand moulds. 
 
 The rolls of rolling mills are subjected to great heat 
 when at work, from the direct contact of glowing iron, 
 as well as from its friction in passing through the 
 grooves. In almost all cases they are cooled with water, 
 which is led through a gutter above the framing, and 
 distributed in small streams over the working surfaces 
 and necks continuously. 
 
 The size and speed of rolling mills vary within 
 very wide limits, according to the character of the 
 work done. Thus reversing mills for heavy plates 
 may make from 25 to 30 revolutions per minute, while 
 small mills rolling wire are driven at from 500 to 600 
 revolutions in the same time. 
 
 In Staffordshire the puddled bar train usually in- 
 cludes two pairs of rolls, from 18 to 20 inches in 
 diameter, and from 3J to 5 feet in length between the 
 bearings. The grooves of the roughing pair are of a 
 curved or Gothic form, as in the right half of Fig. '32, 
 giving a rough square to the bloom. Those of the 
 finishing pair are rectangular, like those on the left 
 side of Fig. 32, and capable of rolling flat bars from 
 2J to 7 inches in breadth, and from half an inch to 2 
 inches in thickness. Sometimes a third pair is added 
 
FORGE AND MILL MACHINERY. 371 
 
 for rolling slabs from 7 to 15 inches wide, which are 
 used as covering plates for piles intended for making 
 plates. 
 
 A mill of the above dimensions serves from six- 
 teen to twenty furnaces. For ordinary- sized merchant 
 bars, the diameter of the rolls is from 12 to 16 inches, 
 and the length from 4 to 6 feet for the roughing, and 
 from 3 to 3 J feet for the finishing pair. The number of 
 revolutions is from 60 to 75 per minute, according to 
 the size of the work. 
 
 In South Wales the rolls used in blooming rail piles 
 are from 20 to 24 inches in diameter, and from 5 to 6 
 feet long. When they are worked as reversing rolls 
 the speed does not exceed from 25 to 30 revolutions per 
 minute ; but compound (three-high) mills may be 
 driven much faster. The finishing train makes from 
 80 to 100 revolutions per minute. 
 
 Plate mills are usually made with three pairs of rolls. 
 The first pair are grooved like those of a bar mill for bloom- 
 ing the pile ; the second are the roughing pair proper ; 
 while those of the third, or finishing pair, are cast 
 with chilled surfaces, and are highly polished. The ordi- 
 nary sizes are from 5 to 6 feet long, and from 20 to 24 
 inches in diameter. The working speed varies from 
 25 to 30 revolutions per minute for heavy, and from 
 30 to 40 for light plates. 
 
 Shears are used for cutting up puddled and other 
 bars into lengths for piling, and also for trimming 
 up the rough edges and ends of finished plates, bars, 
 and sheets. For the former purpose, some form of 
 lever shears, having one fixed and one vibrating jaw, 
 the latter forming one arm of a straight or bent lever, 
 moved by a crank or eccentric, is generally used. 
 
 Fig. 36 is an example of a heavy shearing machine 
 
372 
 
 METALLURGY OF IRON. 
 
 used at Dowlais, in South "Wales, for cutting up puddled 
 bars into lengths for piling. 
 
 When it is required to take a cut of considerable 
 length, guillotine shears, with a diagonal- edged knife 
 which moves vertically between parallel guides, are 
 often used, especially in boiler and other plate work. 
 These are generally machines requiring considerable 
 power, and are driven by a steam engine attached to 
 the same framing. Rails and other thick bars are 
 finished by sawing off the rough or crop ends, and 
 filing down the marks left by the saw while still hot 
 
 Fig. 36. Cropping shear, Dowlais (Truran). 
 
 from the rolls. The circular saws used for this 
 purpose are between 3J and 4j feet in diameter, and 
 are driven either by belts, or, in some instances, by 
 direct- acting steam turbines placed on the same shaft. 
 The number of revolutions varies between 900 and 
 1,300 per minute. 
 
 In the slitting mill the rolls are replaced by spindles 
 carrying a series of steel discs, fixed a certain distance 
 apart by stops. The discs on one spindle interlock 
 with those on the other, forming a rotary shearing 
 
REHEATING AND WF.IT)ING. 373 
 
 machine, with several pairs of blunt- edged cutters. 
 When a thin, flat bar of iron is passed through 
 in the same manner as in an ordinary rolling mill, 
 it is divided by the blades into thin rods of rectangular 
 section, which are delivered in a very crooked con- 
 dition, being bent and distorted by the pressure of 
 the blades. These, when straightened by hand, are 
 made up into bundles for the use of the nail forges, 
 and are known as slit or nail rods. 
 
 CHAPTER XVII 
 
 REHEATING AND WELDING. 
 
 THE rough bars or slabs of malleable iron, obtained 
 in the processes of puddling and shingling, require to 
 be subjected to further treatment in order to produce 
 finished or merchant iron. For this purpose they are 
 cut into short lengths, which are made into nearly 
 cubical packets, or piles, and subjected to a further 
 consolidation by hammering and rolling at a welding 
 heat, until a bar with a uniformly smooth surface, free 
 from cracks or flaws, is obtained. 
 
 The operation of reheating may be performed in 
 several different ways, as, for example, in the open 
 hearth, in direct contact with the fuel a method that, 
 as has already been stated, is commonly practised in 
 making malleable iron in the hearth finery ; in the 
 hollow fire, immediately above the fuel, but without 
 touching it, used in the South Wales forges ; and, 
 finally, in the reverberatory furnace, which is the plan 
 most generally adopted at present. 
 
 The reheating furnace, Fig. 37, also known as the 
 lal-ling or mill furnace, is in external appearance not 
 
374 
 
 METALLURGY OF IRON. 
 
 xmlike that used in puddling, being cased with cast-iron 
 plates in a similar manner. The principal difference 
 is in the proportion between the surface of the fire 
 grate and that of the bed, which is less than is the case 
 in the puddling furnace, as, although a higher tem- 
 perature is requisite, it is less subject to fluctuations, 
 being maintained as uniform as possible. The arch of 
 the roof, except in special cases, is comparatively low ; 
 and the bed, which is made of sand consolidated by 
 pressure when in a moistened condition, slopes from 
 the fire-bridge uniformly towards the flue, in order to 
 
 Fig. 37. Reheating or balling furnace. 
 
 allow the slag or cinder formed by the combination of 
 the sand with the scale on the surface of the iron to 
 run off freely towards the bottom of the stack, where it 
 is let out of the furnace. This, like most of the other 
 slags produced under similar circumstances, is in com- 
 position essentially a tribasic silicate of protoxide of 
 iron, and is distinguished by the name of flue cinder 
 from that of puddling furnace, or tap cinder t the former 
 flowing constantly, while the latter is only removed 
 from the furnace at intervals. A small fire is usually 
 placed in front of the stack both in reheating and pud- 
 dling furnaces, m oraer to prevent the cinder from 
 cooling and becoming solid in the tap hole. 
 
REHEATING AND WELDING. 375 
 
 Fig. 37 is a longitudinal section of a reheating fur- 
 nace, such as is used for bars of ordinary sizes, which 
 are finished from the pile at a single heat. The bed 
 is made of fire-brick, covered with a thick coating of 
 sand. In other respects it is very similar in construc- 
 tion to the puddling furnace. In order to prevent the 
 access of air to the bed, it is necessary to keep the 
 fire grate thickly covered with fuel, and the door must 
 be well stopped for the same reason. 
 
 In reheating small sizes of iron, it is advantageous 
 to use a furnace with a small hearth and large grate, so 
 as to be able to bring up the piles rapidly to a welding 
 heat, in order to prevent the loss by oxidation conse- 
 quent upon unnecessary exposure. When the dimen- 
 sions of the pile are such as to require several passages 
 through the mill in order to reduce it to the proper 
 section, it is often necessary to subject it to a second 
 heating ; for this purpose, furnaces of special construc- 
 tion are used, corresponding in dimensions to the form 
 of the pile at the end of the first heat. When the 
 bed is of a large size, as, for instance, in the furnaces 
 used for reheating unfinished plates, a second fireplace 
 is placed at the flue end, with its axis at right angles 
 to the principal one. This class of furnace is used in 
 reheating long and heavy bars, and also in armour- 
 plate mills. 
 
 Piling for Merchant Iron. The amount of work put 
 into bar iron varies with the quality. For the commoner 
 kinds, puddled bars, or No. 1 iron, cut into lengths, are 
 piled, and when brought to a welding heat are rolled 
 off, either with or without first being worked into a 
 bloom under the hammer. More usually, however, the 
 iron of second rolling, or No. 2, is employed as the 
 top and bottom plates of the piles, when making 
 
076 
 
 MKTALLmiJY OF IRON. 
 
 finished, No. 3, or best iron. Beyond this, if further 
 piled and welded, the iron is distinguished as lest best 
 and treble best, according to the number of heatings and 
 weldings to which it has been subjected, The harder 
 and more granular kinds of iron, such as that used for 
 tires in Yorkshire, are worked almost exclusively under 
 the hammer, the rolling mill being only used in giving 
 the proper figure to the bar at the finishing stage. 
 
 The covering slabs for the tops and bottoms of rail 
 piles are sometimes made by doubling and welding two 
 puddled blooms together under the hammer, which are 
 then reheated and rolled to the proper size without 
 having first passed through the state of puddled bars. 
 The use of single plates for the outsides of piles is 
 necessary in order to get a clean surface, as butt joints 
 do not weld properly unless they are covered. In all 
 cases the ends of the bars forming the pile must be 
 cut square, and all the surfaces in contact must be as 
 clear as possible from scale and rust. 
 
 Piles for bars should be made as thick and square as 
 can be done consistently with the form of the blooming 
 grooves of the mill, in order that the iron may be 
 
 ig. 33. Sections of piles for finished iron 
 
 subjected to great longitudinal extension. The length 
 will of course depend upon the weight of finished bar 
 required. 
 
 Fig. 38 shows the arrangement of the various qua- 
 lities of bars and slabs in pile for different kinds of bai 
 
REHEATING AND WELDING. 377 
 
 Iron. The darker- shaded parts indicate slabs of re- 
 worked No. 2 iron, scrap bars, or similar qualities, the 
 lighter parts being puddled bars. A is one out of many 
 kinds of pile adopted in the manufacture of rails. B 
 and c are Belgian piles for T and girder iron, the 
 finished sections being given in the centre to the same 
 scale. D is Beattie's system of piling or faggoting 
 adopted for railway axles. It consists of a ring, built 
 up of several segments, arranged round a central cir- 
 cular bar. The bars composing the piles are kept 
 together by bands of wire before they are placed in 
 the heating furnace. 
 
 The following example gives the details of manipu- 
 lation in rolling bars of different sizes followed in a 
 South Staffordshire forge in the year 1861 : For bars 
 of 1 inch square the pile was made up of 6 bars, each 
 three-quarters of an inch thick, and 4 inches wide, the 
 top and bottom plates being of doubled blooms, while 
 the intermediate ones were ordinary puddled bars. The 
 length of the pile was 18 inches, and its weight 100 Ibs. 
 
 Two heating furnaces were used, each containing a 
 charge of eighteen piles, which, when at a proper 
 welding heat, were passed eleven times through the 
 rolls, the grooves being arranged as follows: first, two 
 of rectangular section, then five Gothic, and, finally, 
 four square finishers. 
 
 The work done by the two furnaces in twelve hours 
 amounted to 9 tons (long weight) of finished bars. The 
 loss on the weight of the piles was about 15 per cent., 
 an amount made up of 5 to 6 per cent, caused by 
 oxidation in the furnace, and the remainder, 9 or 10 
 per cent., in crop ends and waste in rolling. 
 
 The consumption of coal was from 50 to 55 per cent, 
 of the weight of the finished bars. The time occupied 
 
378 METALLURGY OF IRON. 
 
 in rolling a single heat was from thirty to thirty-fivo 
 minutes. 
 
 In making round bars of 4 inches in diameter and 
 16 feet long, the pile was 10 inches wide, 11 \ inches 
 high, and 6 feet long. The top and bottom were each 
 composed of three thicknesses of puddled scrap bars 
 hammered and rolled, while the centre was made up of 
 five layers of ordinary puddled bars. Three heating 
 furnaces were used, each holding a single pile, which 
 required from two and a half to three hours to bring 
 it to a welding heat. In rolling, the pile was passed 
 through eleven times, being turned a quarter round 
 each time, so as to bring the joints into the vertical and 
 horizontal positions alternately. The loss in the pro- 
 cess amounted to between 30 and 32 per cent., out of 
 which about two-thirds, or 21 per cent., was accounted 
 for in the crop ends. The coal burnt amounted to 65 
 per cent, of the weight of the finished bars. 
 
 In making small sizes of merchant iron, such as smaU 
 round or square bars or hoops, the pile, after being 
 partially drawn to a square bar, is cut into lengths 
 known as billets, which are afterwards finished sepa- 
 rately. The work is done very quickly, although, 
 owing to the small size of the billets, the daily produce 
 expressed in weight is not very large. When the 
 billets are finished in one heat, the consumption of coal 
 is from 11 to 12 cwt. per ton; but when two heats 
 are required, the amount is increased to 20 cwt., or 
 equal weights with the bars produced. 
 
 In South Wales the ordinary weight of the pile for 
 rails is about 15 cwt., long weight, four being placed 
 in the furnace at once ; the whole of these are rolled 
 to blooms in a triple mill in five minutes, each passing 
 through four times alternately flat and edgeways. 
 
REHEATING AND WELDING. 379 
 
 The second heat is effected in half an hour, the furnace 
 being similarly charged, when the blooms are passed 
 through the rail mill nine times, the whole operation 
 being performed in one minute. In order to keep the 
 mill constantly at work, fourteen heating furnaces are 
 required, ten for the first, and four for the second heat. 
 The loss, including the crop ends, is about 20 per cent, 
 on the weight of the pile. In some cases these are 
 passed through a special flattening mill, in order to 
 reduce them to a rectangular figure for greater con- 
 venience in piling, but more generally they are 
 converted into slabs in the same manner as ordinary 
 puddled bars. The special application of crop ends to 
 the manufacture of iron free from phosphorus, by 
 Parry's process, has been previously noticed at p. 285. 
 
 The total amount of coal consumed in the manu- 
 facture of iron from the ore to the finished bars of 
 common, or No. 2 quality, may be taken at five times 
 the weight of the latter, with an increase of about 
 10 cwt. per ton for every additional heat. 
 
 Plates and sheets are divided into classes accord- 
 ing to thickness, the former term being restricted 
 to all sizes above No. 4 of the Birmingham wire 
 gauge, corresponding to a thickness of - 238 inch. 
 Sheet iron is further classified into three divisions, as 
 follows : 
 
 Singles, including from No. 4 to JN ). 20 gauge or 0-238 to O'OSo in. thick. 
 Doubles 20 25 0-035 -020 
 
 Trebles or lattens,, 25 27 0-020 0-016 
 
 The piles for the heavier classes of plates are built 
 up of layers of bars, placed alternately across each 
 other, instead of having their longer sides parallel, 
 as is the case with ordinary bar iron. The covering 
 
380 METALLURGY OP IRON. 
 
 slabs, or top and bottom plates, are flat bars, from 
 9 to 12 or 14 inches wide, and from 1 inch to 1 \ inches 
 thick, which are made by doubling two puddled blooms 
 under the shingling hammer, and rolling to the pioper 
 size at one heat. 
 
 For boiler plates measuring 6 feet long, by 3 feet 
 broad, and yV of an inch thick, weighing about 2^ 
 cwt. each, the pile is made 20 inches long, 6 to 7 
 inches high, and 12 inches broad. The whole of 
 the work is done at one heat ; the pile is reduced to 
 a roughly-squared bloom by passing it lengthways 
 through three grooves in the blooming rolls, then four 
 times through the plate- roughing rolls in the direction of 
 the breadth, which draws it into a thick- squared plate, 
 and finally, three times lengthways through the finish- 
 ing rolls. The difference in weight between the finished 
 plate and the rough bars taken for the pile is from 
 20 to 22 per cent. : this amount includes the waste in 
 reheating and scrap produced in shearing the edges 
 to the proper size. The amount of coal consumed in 
 the reheating furnace is from 14 to 15 cwt. per ton 
 of plates produced. 
 
 For the larger sizes of sheets, such as singles of No. 
 12 gauge, measuring 6 feet in length by 2 feet in 
 breadth, th3 piles, 20 inches in length, 7 inches in 
 breadth, and 4 inches in height, are made up of the 
 scrap and crop ends produced in making the top and 
 bottom plates, which are three-quarters of an inch thick. 
 The weight corresponding to the above dimensions is 
 about 70 Ibs. Nineteen or twenty piles are placed in 
 the heating furnace at once. In passing the blooming 
 rolls, the pile is converted into a bar of double the 
 original length, without any alteration in breadth, and 
 is then cut into two parts, each of which is passed cross- 
 
REHEATING AND WELDING. 381 
 
 ways through, the roughing rolls, until it is reduced 
 nearly to the breadth required in the finished plate. 
 After passing four times lengthways through the finish- 
 ing rolls, the two halves of the original bloom are 
 placed one above another, and passed through together 
 three or four times more ; they are then nearly cold, and 
 are immediately taken to the annealing furnace, where 
 they are subjected to a low heat to soften them, after 
 which they are sheared to the proper size and finished. 
 
 The rolling of thinner sheets is very similar to that 
 last described, except that the piles are of a much 
 simpler character, on account of their smaller weight, 
 consisting simply of three or four plain flat bars. For 
 doubles of 20 to 24 gauge, the rough bar is cut in two, 
 and the halves are passed through the plate rolls, first 
 separately, and then together, as in the preceding 
 instance. The rough sheets are placed together in 
 bundles of four in the annealing furnace, and after 
 heating and passing through the finishing rolls, are 
 subjected to a second heat in the same furnace before 
 being sheared. 
 
 Lattens or trebles of No. 27 gauge, measuring 54 
 inches in length, by 28 inches in breadth, and weighing 
 5J to 6 Ibs. per sheet, are made from roughed-down 
 slabs 4 inches broad, and half or three-quarters of an 
 inch thick, cut into lengths of about 18 inches. These 
 lengths are heated to redness, and passed separately 
 through the roughing rolls, and two or three times 
 through the finishers, after which they are doubled, and 
 the rolling is continued until they have cooled to a dull 
 red heat, the original blank having by this time become 
 extended to a sheet measuring 32 inches by 24. 
 
 In rolling after the first annealing heat, four platey 
 are taken together, and in finishing, which follows 
 
382 METALLURGY OF IRON. 
 
 final or second annealing heat, eight thicknesses are 
 passed through at the same time. Owing to the 
 number of reheatings, and the large amount of surface 
 of the finished work as compared with its weight, the 
 loss and consumption of materials are comparatively 
 large. For the production of 1 ton of sheets sheared 
 to the proper size, 25 cwt. of coal are required, and 
 25 or 26 cwt. of rough bars. Out of the waste of 5 or 
 6 cwt. on the latter quantity, about 4 cwt. are ac- 
 counted for in the shearings and crop ends, produced 
 at different stages of the process. ISFo great amount of 
 scaling takes place, owing to the comparatively low 
 temperature at which the work is done. 
 
 Thin sheet iron or black plate, intended for tinning, is 
 made in a similar manner to that last described, the 
 unfinished work being doubled after every heating, so 
 that at last as many as sixteen thicknesses are passed 
 through the mill together. When reduced to the 
 proper dimensions, the plates are brought to a bright 
 metallic surface by pickling in weak sulphuric acid. 
 A final polish is given by cold rolling, after which the 
 plates or sheets are ready for tinning. 
 
 Yery heavy plates, such as those used for ships' 
 armour, are made either by hammering or rolling alone, 
 or by a combination of both methods. In the first 
 case, the original material is best scrap iron, made into 
 piles weighing from 1 to 1 \ cwt. each, which are balled 
 in threes or fours into a slab at one heat. According 
 to the thickness of the plate required, these slabs are 
 reheated either alone or doubled, and reduced at a 
 second forging to an oblong slab, somewhat thicker 
 than the finished plate, with two squared and two 
 chamfered edges. In finishing, two pieces are joined 
 to form a section of a plate of the required bread'th, by 
 
REHEATING AND WELDING. 383 
 
 joining the tapered edges together on the shorter sides, 
 and finally, the length is made up by adding as many 
 pairs as may be necessary. For convenience of manipu- 
 lation, a staff, or porter lar y with a capstan-headed ring 
 fixed to it, is welded to one of the unfinished plates, in 
 order that it may readily be turned on the anvil, as is 
 usual in all large forgings. The final forging, to reduce 
 the plate to the proper thickness, is effected at a moderate 
 red heat, water being constantly thrown on the surface 
 to clean it from scale. When finished, it is annealed by 
 heating to redness and slow cooling. By the use of 
 tapered edges the surfaces of contact cross the finished 
 plate obliquely. 
 
 Rolled armour plates are put together as follows : 
 The balls from the puddling furnace are shingled and 
 rolled to slabs about 12 inches broad, 30 inches long, 
 and 1 inch thick. Five or six of these slabs are in a 
 second heat rolled to a slab about 4 feet square. At 
 the third piling, five or six slabs of the second heat are 
 welded and rolled into a plate 8 feet long, 4^ feet 
 broad, and 2J inches thick, weighing rather more than 
 30 cwt., and made up of between twenty-five and 
 thirty- six original inch slabs of No. 1 iron. 
 
 The edges of the plates require to be kept as true as 
 possible, so that a certain amount of shearing may be 
 necessary at the intermediate step of the process. For 
 the finished plates of 4| or 5J inches in thickness, four 
 of the large 30-cwt. plates are piled together, and re- 
 heated in a furnace having a fireplace at either end. 
 In order that the whole pile may be uniformly heated, 
 the lower surface, instead of touching the bed of the 
 furnace, is supported on six small pillars of brickwork, 
 so as to allow the flame to pass below it. The door of 
 the furnace is placed parallel to the axis of the rolling 
 
334 METALLURGY OF IROS. 
 
 mill, and the pile, when sufficiently heated, is dravrn 
 forward with tongs, and received on a truck, which 
 runs upon a railway directly to the rolls. A similar 
 truck is placed on the opposite side of the mill, and 
 the pile is passed forwards and backwards by reversing 
 the rolls until it is reduced to the proper thickness. 
 The surfaces of these trucks incline towards the rolls, 
 or are provided with friction rollers, so that the pile 
 may be easily pushed between them by hand, the force 
 of the rolls being sufficient to drive it up the incline of 
 the receiving surface. The plate, after leaving the rolls, 
 while still hot, is placed upon a cast-iron table, and 
 rendered perfectly smooth and flat by passing a roller 
 weighing 7 tons over it. When cold, the rough edges 
 are dressed up square on a planing machine. Armour 
 plates are now regularly made of all thicknesses up to 
 24 inches. The manufacture of steel-faced or com- 
 pound plates is noticed in the next chapter. 
 
 The composite character of rolled bar iron made 
 from large piles may be rendered evident by etching 
 a polished transverse section with weak sulphuric acid, 
 when a series of irregular curved lines will be developed, 
 corresponding to the original surfaces of contact of the 
 component slabs. Uniformity in the character of the 
 lines is a sign of good welding ; but black irregular 
 patches indicate that the cinder has not been entirely 
 expelled. 
 
 Application of the Waste Heat of Puddling and Re- 
 heating Furnaces. Under ordinary circumstances, the 
 heat developed by the coal burnt in the fireplaces of 
 these furnaces is but imperfectly utilised, as the flame 
 leaving the hearth at the welding temperature of iron 
 escapes into the atmosphere at the top of the etack : 
 carrying away an amount of heat greatly in excess of 
 
HKHEATING AND WELDING, 885 
 
 that necessary to keep up the draught of air through 
 the fire. In order to economise some portion of this 
 heat, various methods have been adopted of interposing 
 cooling substances by passing the flame through the 
 flues of steam boilers or blast-heating stoves. The 
 former method is used for furnaces fired with solid 
 fuel, while the latter is more especially adopted for 
 gas furnaces . A more complete method than either 
 is the so-called regenerative gas furnace of Siemens, 
 where the waste heat is applied in raising both the 
 gases used as fuel and the air for burning them to a 
 high temperature previously to their arrival at the 
 point of combustion, by which means a very high and 
 uniform heat is attainable. 
 
 The commonest form of boiler used for raising steam 
 by the waste heat of forge and mill furnaces is a 
 vertical, cylinder with a hemispherical dome. The 
 flame either passes round the outside, or through a 
 central flue connected with the external shell by a 
 series of horizontal tubes. Generally two furnaces are 
 in connection with the same boiler. A more perfect 
 method, but one that can only be adopted in large 
 works, is to lead the flame from a considerable number 
 of furnaces into a single horizontal flue of propor- 
 tionately large section, which carries it through the 
 heating tubes of the boiler. The resistance opposed 
 by the interposed obstacles is overcome by the draught 
 of a tall chimney. In this way there is no chance of 
 the working either of the furnaces or boilers being 
 checked by alternations of temperature, as may some- 
 times be the case when only one or two furnaces are 
 used with a separate boiler. 
 
 In Hungary and Austria different combinations of 
 reheating aud puddling furnaces fired with gaseous 
 
386 
 
 METALLURGY OF IRON. 
 
 fuel have been recently adopted. At Rhonitz a 
 furnace of this kind has an ordinary gas generating 
 chamber for burning wood, combined with three 
 hearths placed in one longitudinal series. The first 
 of these is intended for reheating blooms and billets 
 of iron. It receives the full stream of the heated 
 gases which contain no uncombined oxygen from 
 the generator before they reach the point of final com- 
 bustion at the top blast jets, which are placed in the 
 usual position above the fire-bridge of the puddling 
 hearth. The third bed is used for warming up the 
 pig iron before melting it in the puddling process. 
 Lastly, the flame, before entering the stack, is carried 
 round a blast-heating arrangement consisting of two 
 vertical cast-iron pipes, divided by central partitions, 
 which raises the air employed in the top blast to a 
 temperature of 200. 
 
 A furnace of this class is found to be productive of 
 a certain economy in iron, 129J Ibs. of pig iron being 
 sufficient to produce 100 Ibs. of billets instead of 134 Ibs , 
 as was the case when the puddling and reheating were 
 effected in separate furnaces. The saving of fuel is, 
 however, very considerable, 7*9 cubic feet of wood 
 being now found sufficient when 18 cubic feet were 
 formerly required. 
 
 A somewhat similar combination to the preceding 
 is applied to the waste heat of an open reheating fire 
 at Beichenau. The hearth is of the usual rectangular 
 form, but is blown with two twyers instead of one. 
 The fuel employed is charcoal. The hood covering 
 the hearth resembles the roof over the fireplace of a 
 reverberatory furnace. The flame, together with a 
 considerable quantity of inflammable gas derived from 
 the incomplete combustion of charcoal dust or braise 
 
REHEATING AND WELDING. 387 
 
 on the first hearth, is led into the second, or puddling 
 bed, where it meets the second blast, which is heated 
 to about 200, and is introduced through a line of 
 narrow twyers, extending along the fire-bridge, and 
 inclined at a considerable angle to the direction of the 
 gaseous current. Behind the puddling bed are placed 
 two others, for warming the iron at various stages in 
 the process, which may be distinguished as Nos. III. 
 and IY., and the lower part of the stack contains the 
 blast-heating pipes, which are of the horizontal serpen- 
 tine form. The different parts of this furnace used are 
 as follows : The puddled balls from, the second bed, 
 after being shingled into blooms, ^re subjected to a 
 preliminary heat in the fourth, or last, which also 
 serves for heating the pig iron previously to puddling, 
 and are then transferred to the charcoal fire, No. I., 
 where they are brought up to the proper temperature 
 for conversion into puddled slabs or rough bars. The 
 finished iron, which in this case is intended for waggon 
 tires, is produced by reheating the rough bars of the 
 preceding operation in hearth No. III., and drawing 
 them to the proper shape under the hammer. This is 
 said to be a very economical furnace, in spite of its 
 apparent complication. The consumption of materials 
 in the different stages is as follows : 
 
 160 Ibs. pig iron give 100 Ibs. blooms; 
 
 114 Ibs. blooms ,, 100 Ibs. puddled bars ; 
 
 104 Ibs. puddled bars ,, 100 Ibs. finished tire iron ; 
 
 corresponding to a total consumption of 126 Ibs. of 
 pig iron and 12 cubic feet of charcoal per 100 Ibs. of 
 finished iron. 
 
 Siemens' regenerative gas furnace, as applied to 
 puddling, is similar in general character to the cast- 
 
 8 2 
 
388 METALLURGY OF IRON. 
 
 steel melting furnace described at p. 376, supposing a 
 puddling chamber to be substituted for that contain- 
 ing the melting pot a in Fig. 43. The puddling bed 
 is made of cast-iron plates, surrounded by hollow 
 boxes cooled with water in the usual way ; the bridges 
 and flues at either end aie exactly similar, so that 
 the current of heated gases may be made to travel in 
 either direction without affecting the working of the 
 furnace. Below the ground level are placed four large 
 vaulted chambers, separated from each other by thick 
 walls, and filled with fire-bricks arranged in cellular 
 piles, similar to those in Cowper's stove, as shown in 
 Fig. 15, p. 170. These, the so-called regenerators, are 
 employed to keep back a portion of the heat carried 
 away by the gases after they have done their work in 
 the puddling chamber, and which, in furnaces of the 
 ordinary construction, is lost by allowing the flame to 
 pass directly into the chimney. The heat taken up 
 by the bricks is transferred to the inflammable gases 
 used as fuel, and the air intended for burning them 
 before their admission to the point of actual com- 
 bustion, by which means a much higher temperature 
 can be obtained than is possible with furnaces of the 
 ordinary form, burning solid fuel on a grate. 
 
 In Figs. 39 and 40 (taken from Tomlinson's " Cyclo- 
 paedia") the principal details of the regenerative fur- 
 nace are shown as applied to plate-glass melting, and 
 although intended for a different purpose from that at 
 present under consideration, will be sufficient to illus- 
 trate the principle of the invention, the whole of the 
 construction being generally similar, with the exception 
 of course of the chamber containing the melting pots D, 
 which we must imagine to be replaced by a puddling 
 furnace of the form indicated in the preceding paragraph. 
 
REHEATING AND "WELDING. 380 
 
 The gas producer, Fig. 39, is a large chamber, of 
 
 triangular section, capable of holding several tons of 
 
390 METALLURGY OF IRON. 
 
 fuel, small coal or slack being usually employed. The 
 charging is effected through the stoppered hole a. The 
 coal travels slowly down the inclined wall b, becoming 
 gradually heated and parting with its volatile matters 
 until it reaches the step grate c. This is formed of a 
 number of broad thin-edged bars, overlapping each 
 other like the laths of a Venetian blind, so as to leave 
 only a series of narrow spaces between them for the 
 admission of air. The combustion goes on very slowly, 
 the small amount of carbonic acid produced at the bars 
 being immediately decomposed by the thick column of 
 incandescent fuel above, so that the contents of the 
 chamber are gradually converted into inflammable gas, 
 chiefly carbonic oxide, which, diluted with the nitrogen 
 of the air remaining after combustion, is subsequently 
 employed as fuel in the puddling furnaces. At one 
 time a certain amount of steam was introduced from 
 a perforated pipe at d, which was filled with water 
 and heated by the spare heat of the fire. The steam, 
 in its passage over the ignited carbon, was decomposed 
 with the formation of carbonic oxide and hydrogen, 
 whereby the calorific value of the gas was considerably 
 increased. This part of the process has since been 
 given up, owing to the difficulty of regulating the 
 amount of steam injected, and the great absorption of 
 heat caused by the decomposition was found Co give 
 rise to an. injurious local cooling unless the operation 
 was very carefully watched. 
 
 The gas evolved from the generator passes through 
 the valve g into the stack H, whence it issues at a tem- 
 perature of about 200. In traversing the horizontal 
 iron pipe r, it loses about one-half of its heat, so that its 
 density is sufficiently increased in the descending pipe 
 p' lo establish a continuous draught from the gas pro- 
 
REHEATING AND WELDING. 
 
 391 
 
 duced towards the furnace without the use of a special 
 chimney. 
 
 The position of the two generators f'"f"" is shown 
 in the half plan at L M in Fig. 40. The other two, 
 
 
 "Plan at L.M. 
 
 Fig. 40. Siemens' furnace. Plan of flues. 
 
 f'f f/ > are similarly placed, a.s indicated by the dotted 
 lines. The arrangement of the bricks will be under- 
 stood from the section in Fig. 39, as well as that 
 already given in Fig. 15. They are worked in pairs, 
 two being heated by the waste flame, while others are 
 giving up their heat to the cold gases and air. Owing 
 to the large amount f surface presented by the bricks, 
 the absorption of the surplus is effected with compa- 
 rative rapidity, and the temperature of the current 
 escaping to the chimney is reduced nearly to the 
 boiling point of water. As soon as the brickwork 
 has attained the proper temperature in two of the 
 chambers, the current is turned into the adjoining pair 
 by reversing the valves r r, Fig. 39, and r r" t Fig. 40, 
 and the heat accumulated in the brickwork is abstracted 
 
392 METALLURGY OF IRON. 
 
 by cold air, to pass through, one, and gas through the 
 other, until the second pair is heated, and so on, the 
 process being kept up continuously, notwithstanding 
 the intermittent actioi. of the regenerators taken sepa- 
 rately. 
 
 When applied to puddling iron, a current of heated 
 gas is brought into the furnace by a narrow rectangular 
 chamber, opening into a slit in the body of the fire- 
 bridge. The air comes through a parallel flue behind, 
 and at a higher level, in order that it may, from its spe- 
 cifically greater weight, fall towards the upward stream 
 of gas, and become perfectly mixed. As in all other gas 
 furnaces, the nature of the atmosphere may be perfectly 
 regulated by varying the amount of air introduced. 
 This is a point of great importance in reheating furnaces, 
 where it is necessary to keep out free air as much as pos- 
 sible, in order to prevent the iron from burning to waste. 
 
 The regenerative principle has been adopted by 
 Lundin, at Munkforss, in "Wermland, for a gas- welding 
 furnace, fired with a very unpromising material, namely, 
 sawdust, containing from 50 to 60 per cent, of water. 
 A condenser containing a series of pipes, terminated 
 with finely-perforated injection roses, adjoins the gas 
 producer, so that the issuing current of gas is imme- 
 diately brought in contact with a shower of finely- 
 divided water, the jets being arranged to cross each 
 other, and reach every part of the condensing chamber. 
 The temperature is thus reduced from 350 or 400 to 
 35 or 40, and nearly the whole of the steam mixed 
 with the gas is condensed, together with the tar, pyro- 
 Ugneous acid, and such other volatile substances pro- 
 duced from the destructive distillation of the sawdust 
 as may be susceptible of condensation by the action of 
 w\ter. In addition to the water jets, a second con- 
 
REHEATING AND WELDING. 393 
 
 densing chamber is used ; this is filled with wrought- 
 iron bars, piled like the bricks in the regenerators, 
 which are cooled by a constant flow of water. 
 
 The gas issuing from the condenser, after cooling 
 and drying, is said to retain only 4 per cent, of water 
 vapour. Of course a considerable amount of heat is 
 lost by the enforced cooling, and has to be taken up 
 again in the regenerators ; but this disadvantage is 
 small as compared with the increased heating power 
 gained by the removal of the water. The regenerators 
 for heating the gas are one-fourth larger in area than 
 those through which the air passes. The consumption 
 of sawdust by this furnace is at the rate of from 11 to 
 14 cubic feet for each 100 Ibs. of finished iron. 
 
 According to Siemens' calculation, the surface neces- 
 sary in the regenerators is six square feet, to take up 
 the heat produced by the combustion of one pound of 
 coal per hour, corresponding to 510 square feet for a 
 consumption of 10 cwt in the day of 24 hours. The 
 cubic capacity of the regenerators for this amount of sur- 
 face is ]22 cubic feet ; and, as the bricks occupy half the 
 space, the volume of the latter is 61 cubic feet, and 
 their specific gravity 1*8 making a weight of 1,715 Ib. 
 for each chamber. As the specific heat of bricks is 
 0*21, or the calorific capacity 153*4, they may be con- 
 sidered as equivalent, thermally, to 1,260 Ib. of gas, or 
 1,128 Ib. of air. As, however, it is necessary, for the 
 complete combustion of the gases, to admit an amount 
 of air not less than 20 per cent, in excess of the 
 theoretical quantity, the air regenerators are made 
 iarger than those used for heating the gas in the propor- 
 tion of 7 to 4 as a maximum. This provision for vary- 
 ing the amount of air, while the composition or the gas 
 
 remains constant, allows the production of a neutral. 
 
 s 3 
 
394 METALLURGY OF IRON. 
 
 oxidising or reducing flame, according to the require- 
 ments of the process. 
 
 An investigation of the calorific effect of the Siemens' 
 furnace, in regard to the distribution of the heat de- 
 veloped, has been recently published by Krans. He 
 calculates that the amount of heat expended by the 
 indirect consumption of the fuel, i.e., by converting it 
 into carbonic oxide, to be about 31*7 per cent, of the 
 theoretical effect produced by complete combustion. 
 
 The work done by the gas burnt in the furnace, taking 
 it as similar in composition to that of the glass-melting 
 furnaces at Saint Gobain, and to be burnt with 20 per 
 cent, excess of air, is as follows : 
 
 Heat lost in the stack 11 -31 per cent. 
 
 in the regenerator by trans- ") lo-s" ^23-86 
 
 mission . . . j ' " 
 
 employed in raising iron to the ^ 
 
 welding temperature taken at > 15-48 
 
 1600 .... } ^7G'14 
 
 remaining in furnace and trans- ) rr . ra 
 
 mitted through walls . j 6C 
 
 100-00 100-00 
 
 Of the total heating effect derivable from the gases, 
 therefore, 76 '14 per cent, is utilised, and23'86 per cent, 
 lost, or rather, not applied directly to the work. Taking 
 into account the loss of 31*71 per cent, incurred in the 
 gas generator, we have, as the total duty of the coal 
 burnt, 52 per cent., and the loss 48 per cent. When it 
 is considered that these figures represent a result many 
 times more favourable, as regards utilisation of heat, 
 than that of the ordinary system of burning coals on 
 the grate of a reverbatory furnace, we may realise to 
 some extent the enormous loss in the stack of an 
 ordinary puddling or heating furnace. 
 
 At Weilersbach, near Trier, pig, smelted with a 
 
REHEATING AND WELDING. 395 
 
 mixture of charcoal and coke, is treated in Siemens' 
 puddling furnace, with, the following result: Tho 
 charge, weighing 4 cwt., is worked under the cinder, 
 the boiling being allowed to progress for some time 
 without stirring, by which means a pasty mass of 
 white iron, containing only combined carbon, is formed 
 on the bottom in a condition favourable for being 
 thoroughly and uniformly worked by the subsequent 
 labour of the puddler. As the bed of the furnace is 
 very quickly acted upon, it is necessary to cool it down 
 after the working of each heat, and repair it with a few 
 shovelsful of hammer scale, and, after every second or 
 third, a portion of malleable scrap is added, in order 
 to keep up the necessary covering of slag over the iron 
 bottom. In ordinary work, 10 heats of 4 cwt. are 
 made in the 24 hours. 100-5 Ibs. to 106'51bs. of pig 
 iron is required per 100 Ibs. of puddled bars, and the 
 consumption of coal is 85 Ibs., or, in the most favourable 
 cases, 70 Ibs. With the ordinary furnaces, the quantities 
 are 115 Ibs of pig iron and 140 Ibs of coal per 100 Ibs. of 
 puddled bars ; showing a saving of from 7 to 8 per 
 cent, in the waste of iron, and about 50 per cent, in the 
 fuel. At De Wendel's works, on the Moselle, similar 
 results were obtained with the white pig iron of 
 Hayange, in a furnace fitted with a mechanical puddler, 
 and taking charges of 8 cwt. From 14 to 15 heats 
 were made daily, with a consumption of 106 Ibs. of pig 
 iron and 70 Ibs. of coal per 100 Ibs. of puddled bars; but 
 the quality of the latter was not 'good, the amount of 
 phosphorus retained being greater than in the bars 
 produced in the ordinary furnace. Kosman attributes 
 this to a want of oxidising power in the flame, and to 
 the more acid character of the slag (it contained 15 per 
 cent, of silica, as against 12 per cent, in the ordinary 
 
METALLURGY OF IRON. 
 
 furnace), which worked injuriously by being deficient 
 in peroxide or magnetic oxide of iron, which is will 
 known to be the most potent oxidising agent in the 
 process of puddling, and by its greater fluidity, which 
 prevented the charge being thoroughly worked without 
 a great loss of time. The extreme heat of the furnace 
 is also supposed to be in some degree chargeable with 
 the result, as the affinity of carbon for iron is said to 
 be increased at very high temperatures, which renders 
 the fining difficult, resulting in the production of a 
 steely, imperfectly-refined product, instead of the soft 
 malleable iron required. From this reasoning, there- 
 fore, we may be led to the conclusion that the Siemens' 
 furnace can be more advantageously applied in pro- 
 cesses where heat alone is required, as, for example, in 
 reheating, or the fusion of steel, than for puddling. 
 At Bolton, the results obtained in this furnace are as 
 follows, according to Siemens : The yield was at the 
 rate of 20 cwt. 2 qrs. 2 Ibs. of pig iron per ton of pud- 
 dled bar ; while, in the ordinary furnace, 22 cwt. 2 qrs. 
 20 Ibs. were required, thus showing a saving, as far as 
 loss of iron is concerned, of about 10J per cent. The gas 
 furnace worked off eighteen heats per shift of 24 hours, 
 while the ordinary furnace made only twelve in the 
 same time. The exact saving of fuel could not be ascer- 
 tained, because some reheating furnaces were worked 
 from the same set of gas-producers, but it is estimated 
 at from 40 to 50 per cent. The amount of red ores 
 used for fettling was somewhat increased, but when 
 the furnace was supplied with water bridges this was 
 reduced to the average proportion of 92'6 Ibs. per 
 charge, in addition to the ordinary allowance of bull- 
 dog, while the yield per charge of 1:84 Ibs. of grey 
 forge pig was increased to 4b5 Ibs, of puddled bar, or a 
 
REHEATING AND AVELDIXG. 397 
 
 slight gain on the weight instead of the ordinary loss 
 of 12 per cent. 
 
 At Monkbridge, near Leeds, the yield of puddled 
 bars was 95 per cent, of the weight of the pig iron 
 charged, while in the ordinary furnace it was only 
 88 per cent. ; in the former case, however, red ore was 
 used to the extent of 3. cwt. per charge of 6 cwt. of 
 grey forge pig, while in the latter only one-third of 
 that quantity was used for the same weight of charge. 
 There was a saving of fuel in the proportion of 16 cwt. 
 to 20 cwt.; but this was only obtained by the use of a 
 better quality of coal in the gas producers than was 
 required in the ordinary furnaces, this being in part 
 due to the gas being employed for reheating and steel 
 melting as well as puddling. 
 
 A simpler construction of regenerator than that of 
 Siemens' is adopted in the heat recuperator of Ponsard, 
 illustrated by Fig. 40 A. This represents a heating fur- 
 nace with a gas producer in immediate connection with 
 it placed below the level of the floor. The producer 
 may, as in the figure, be supplied with air at the ordi- 
 nary temperature through the bars of a step grate, or it 
 may be heated, when, however, grates cannot be used, as 
 they would be rapidly destroyed by the local intensity 
 of the combustion ; and the producer must be entirely 
 constructed of fire-brick, the air being supplied by a 
 steam jet injector. The gas from the producer is 
 delivered directly to the furnace without cooling, carry- 
 ing all the condensible hydrocarbon of the coal with it, 
 instead of depositing them as in Siemens' producer, 
 and is ignited upon the fire-bridge by a current of 
 heated air brought through a parallel channel behind 
 the gas flue. The flame, after leaving the furnace, passes 
 by a flue, a, under the hearth into the recuperator, a 
 chamber filled with bricks, part solid and part hollow, 
 
398 
 
 METALLURGY OF IRON. 
 
 arranged, as in Figs. 40u and 40c, in numerous vertical 
 passages, the adjacent ones being separated, while the 
 alternate ones are connected by the horizontal channels 
 in the perforated bricks. The flame passes downwards by 
 the passages b b, while a supply of cold air, admitted 
 through a valve at the bottom of the chamber, travels 
 in the opposits direction upwards through the alter- 
 nate passages c c, the action being continuous, as in a 
 pipe stove, instead of intermittent, as in Siemens' re- 
 generator. The heating surface is about 10 square 
 
 Fig. 40A. Ponsard's Gas Furnace. 
 
 feet for every cubic foot of bricks in the chamber ; the 
 air is heated up to 900 or 1,000 degrees before it enters 
 the furnace. The joints in the brickwork are kept 
 tight by shallow grooves in the surfaces of contact, 
 which, being filled by the mortar, swell when heated. 
 
 Two kinds of bricks are used, hollow ones, whose 
 lioear dimensions are in the ordinary proportion of 
 1 : 2 1 3, and solid ones which are elongated and square 
 
REHEATING AND WELDING. 
 
 399 
 
400 METALLURGY OF IRON. 
 
 in section, or in the proportion of 1 : 1 : 3 ; the former 
 are laid in lines transversely to the length of the fur- 
 nace, and the latter are placed end to end parallel to 
 that direction. The supply of gas to the furnace is 
 regulated by the sliding damper placed above the outlet 
 of the producer. The air in the recuperator being 
 always at a somewhat higher pressure than that of the 
 burnt gases, any leakage that may take place from 
 defective joints in the brickwork will be from the air 
 to the gas flues, whereby the gas will be more com- 
 pletely burnt without causing any other inconvenience 
 than that of increasing the amount of air required. 
 
 These furnaces have been used for melting spiegeleisen 
 as well as for reheating in rolling mills, and give an 
 economy of 30 to 70 per cent, over those fired by grates 
 in the old way. The cost is about one-half of that of 
 a Siemens' furnace of the same capacity. 
 
 The same principle is followed in Gaillard and Hail- 
 lot's furnace, who, however, modify the construction of 
 the recuperator by combining with vertical air channels 
 horizontal ones in the form of clay tubes, with compa- 
 ratively thin walls for the waste flame. This is said to 
 give a simpler construction with fewer joints in the 
 brickwork than Ponsard's. 
 
 In Bicheroux's gas furnace, which is much used for 
 heating steel ingots in rolling mills, the air supply is 
 heated by passing through a long flue, which extends 
 below the bed for its entire length and nearly the 
 whole breadth. A high temperature is thus obtained 
 on account of the very large surface exposed, the bed 
 being from 25 to 30 feet long, and 5 to 6 feet broad. 
 A furnace of this size will heat 75 tons of steel ingots 
 
 o 
 
 per day, with a consumption of 11 to 13 per cent, of 
 their weight of small coal. 
 
METHODS OF PRODUCING STEEL. 401 
 
 Another class of gas furnace, that of Boetius, is 
 somewhat similar to Bicheroux's, having no regenera- 
 tor, the waste heat of the flame either escaping or being 
 utilised to raise steam in boilers ; but the combustion 
 is effected with warm air, which is heated by passing 
 through a series of flues in the casing walls of the gas 
 producer, which are very thin and transmit heat freely. 
 The producer is closed by an arched roof, having only 
 a narrow slit at one side for the exit of the gas, which 
 is met immediately by currents of heated air issuing 
 from a similar passage in the roof behind and from the 
 fire bridge in front, producing a large body of flame, 
 which passes by a plunging flue into the hearth of the 
 furnace. The saving of fuel is from 15 to 20 per cent, 
 of that required in the ordinary heating furnace. 
 
 In a new form of Siemens' furnace an arrangement 
 is adopted for using continuous regenerators, and the 
 conversion of the coal into gas is effected in closed 
 producers with air previously heated and brought into 
 the centre of the mass of fuel by an injector. 
 
 CHAPTER XYIII. 
 
 METHODS OF PRODUCING STEEL. 
 
 In the first chapter it has already been stated that 
 steel forms an intermediate link between ordinary cast 
 and malleable iron, and unites in a greater or less 
 degree the properties of both. It may be produced in 
 many different ways, of which the following are the 
 more important : 
 
 1. By the Catalan forge, directly from the ore. 
 
 2. From pig iron, by fusion and partial oxidation in 
 the hearth finery. 
 
 3. From the same metal, by a similar process in the 
 puddling furnace. 
 
METALLURGY OF IRON. 
 
 4. By exposing bar iron to the action of solid or 
 gaseous carbonaceous matter at a temperature below its 
 melting point. This method is known as conversion by 
 cementation, and the amount of change produced is 
 mainly dependent iTpon the time employed. When 
 merely a surface coating of steel is required, the process 
 adopted is known as case-hardening; while, on the 
 other hand, if sufficiently long continued, the iron may 
 be completely converted into cast iron. 
 
 A process which may be regarded as the reverse of 
 cementation is practised to a certain extent upon cast 
 iron, by exposing it to heat in closed vessels filled with 
 finely-powdered hematite. The surface of the casting 
 is decarburised at the expense of the oxygen of the 
 peroxide of iron, with the production of a malleable 
 coating. This is known as the method of making 
 malleable cast iron. 
 
 In the above processes steel is produced without 
 melting, and is converted into bars by hammering and 
 rolling, in a similar manner to that adopted in the 
 manufacture of malleable iron. A more homogeneous 
 product may be obtained by fusion, according to the 
 following methods : 
 
 5. The cemented or blister steel produced in No. 4 
 is broken up into small pieces and melted in crucibles, 
 with or without fluxes, in quantities of from 60 to 
 80 Ibs. This is the original method of making cast 
 steel introduced by Huntsman, in the neighbourhood of 
 Sheffield, and is still largely used in the same district 
 for the production of the higher class of cutlery and 
 tool steel. 
 
 6. By blowing air through molten pig iron until it 
 is wholly or partially decarburised. In the former 
 case the necessary amount of carbon is restored by the 
 
METHODS OF PRODUCING STEEL. 403 
 
 addition of highly- car bur ised pig, such as spiegel- 
 eisen, in small quantity. This is what is known as 
 Bessemer 's process. 
 
 In addition to the above processes, several new 
 methods of making cast steel have been proposed and 
 adopted to a certain extent, but not generally. The 
 essence of these methods consist in fusing cast iron 
 with oxidising, or wrought iron with carburising 
 additions, or by fusing cast and wrought iron in proper 
 proportions alone, as in the last step of the Bessemer 
 process. The following are some of the more promi- 
 nent : 
 
 Uchatius* Process. This consists in melting in cm 
 cibles granulated pig iron with peroxide of iron, pro- 
 duced from roasted spathic iron ore, and a small quantity 
 of oxide of manganese. By varying the proportions ol 
 metal and ore, and especially by the addition of a 
 certain quantity of malleable scrap iron, a softer or 
 milder steel may be obtained. 
 
 Obuchow's method of producing cast steel is generally 
 similar to that of Uchatius. White pig iron is fused 
 with malleable iron or steel scrap, with variable addi- 
 tions of magnetic iron ore, titaniferous black sand, such 
 as is obtained in gold-washing, arsenious acid, nitre, 
 and clay, or with arsenious acid and magnetite alone. 
 The operation is conducted as follows: The scrap iron, 
 magnetic oxide, and clay are placed in a large clay 
 cruel }le which has been previously brought up nearly 
 to a white heat ; the cast iron is then run in melted 
 from a cupola, and the crucible is heated until the 
 contents are perfectly fluid ; the remaining ingredients, 
 namely, arsenious a- 1 id and nitre, are then added, the 
 whole being well stirred. The steel i3 cast in closed 
 cast-iron moulds, and the ingots, as soon as *hey have 
 
404 
 
 METALLURGY OF IRON. 
 
 cooled down to a red heat, are removed, and taken at 
 once to the hammer and tilted. 
 
 Price and Nicholson's process consists in melting mal- 
 leable iron with refined metal, that is, pig iron free from 
 silicon, the relative proportions of the two metals 
 being adjusted according to the character of the steel 
 that it is desired to produce. 
 
 Indian cast steel, or Wootz, is made from malleable 
 iron cut into small pieces, which are charged in 
 quantities of about 1 Ib. weight in clay crucibles, 
 together with about 10 per cent, of dried wood of 
 Cassia auriculata, and two or three leaves of Asclepias 
 gigantea. The covers of the crucibles are luted on with 
 clay, and when dry, some twenty are heated together 
 in a charcoal hearth for about two hours. On breaking 
 the crucible after fusion, a lound cake of steel is 
 obtained, about 1 inch in thickness and 5 inches in 
 diameter, which is perfectly smelted, and usually pre- 
 sents a series of finely-radiating striations on its upper 
 surface. Wootz is extremely hard, containing a large 
 amount of carbon, and requires great care in tempering 
 and forging. 
 
 The addition of charcoal or other carbonaceous 
 matter in the fusion of blister steel furnishes a ready 
 method of controlling the hardness of cast steel, and 
 is commonly practised, especially where a proportion 
 of malleable) iron is added to the charge. The same 
 effect may be produced by the use of crucibles made of 
 blacklead instead of clay, the carbon required for the 
 conversion of the malleable iron into steel being fur- 
 nished by the substance of the crucible : the latter 
 modification is said to be largely used by Krupp at 
 Essen, in Westphalia. 
 
 In making the so-called natural steel in open fires, 
 
METHODS OV PRODUCING STEEL. 405 
 
 a method that was formerly practised to a considerable 
 extent in Styria, Westphalia, and other parts of 
 Europe, but which is now being rapidly superseded by 
 more improved processes, the hearth differs from that 
 used in making malleable iron by having less depth, 
 while the twyer is at a lower level and more strongly 
 inclined, as the molten mass is not brought directly 
 before the twyer, but is decarburised under the joint 
 influence of the blast and slag, with an increased 
 expenditure of time and fuel. As a rule, about double 
 the quantity of coal and one-half more time is required 
 to convert a charge of pig iron into steel than would 
 be the case if the same weight was operated upon for 
 malleable iron. The best varieties of pig iron for the 
 purpose are those containing a considerable quantity of 
 carbon, such as spiegeleisen, or the strongly-mottled 
 variety called blumige floss, containing flowers or spots 
 of grey upon a white ground. Dark grey pig can be 
 used, but should first be subjected to refining. 
 
 In Styria the process is conducted on hearths, with a 
 bottom of charcoal dust about 12 inches thick. The 
 first portion of the charge, weighing 120 Ibs., is melted 
 down with a small quantity of cinder, the latter beicg 1 
 strewed over the coals, the reheating of the blooms 
 (masseln), about ten or twelve in all, from the former 
 operation, going on at the same time. When only two 
 blooms are left, a further addition of pig iron is made 
 to the extent of from 30 to 60 Ibs., and the blowing 
 is continued until the hearth is filled to within 1 or 2 
 inches of the twyer. The fire is then allowed to go 
 down quickly, the slag is tapped through a hole in 
 the front plate into a trough filled with water, and the 
 lump of crude steel remaining in the hearth is allowed 
 to cool, out of contact of the air, by covering it with 
 
406 METALLURGY OF IRON. 
 
 a shovelful of moistened cinders. In about a quarter 
 or half an hour after stopping the blast, the lump is 
 lifted out of the furnace, and is then divided under 
 the hammer into ten or twelve pieces, which, as has 
 already been stated, are reheated during the fining of 
 the next charge. 
 
 The bars drawn under the hammer are hardened by 
 quenching in cold water, and broken, in order to test 
 their quality. They are sorted according to hardness 
 into several classes, distinguished by special names. 
 The best are known as chisel or tool steel, noble steel, 
 and crude steel, below which come a variety of steely 
 irons, used for scythe-making, waggon-wheel tires, 
 and similar purposes. Usually the forges are small, 
 each containing two fires and a hammer, having three 
 water wheels, two for the bellows, and one driving the 
 hammer, which weighs from 5 to 6 cwt., making from 
 70 to 120 strokes per minute, with a maximum lift of 
 about 2 feet. When small- sized bars or scythes are 
 made in the same forge, a lighter tilt-hammer of 3 or 
 4 cwt. is generally used. With both fires at work, 
 four men produce about 12 or 15 cwt. of crude steel 
 blooms in sixteen hours. The consumption of charcoal 
 is about 30 cubic feet per cwt. under ordinary condi- 
 tions, but may be reduced to between 22 and 25 cubic 
 feet by using covered hearths and hot blast. The 
 proportional yield of the different kinds of steel is 
 as follows for every 100 parts of pig iron treated : 
 
 60 parts of steel of all kinds (crude, noble, and chisel steel). 
 
 20 ,, mock, or over-refined steel, containing soft iron. 
 
 10 steely iron of different kinds. 
 
 _K) loss. 
 
 100 
 
METHODS OF PRODUCING STEEL. 4Q7 
 
 The Carinthian process is carried out with much 
 larger quantities of pig iron at one time than the 
 Styrian. The charge, weighing ahout 5 cwt., is melted 
 down in a hearth some 2 feet square, with an effective 
 depth of from 7 to 9 inches below the twyer. The 
 bottom of the hearth is lined with charcoal dust or 
 brasque in the usual way. The twyer is about 1J 
 inches wide, and plunges from 10 to 16. The 
 charge is kept melted before the blast for three hours, 
 as in the ordinary process of refining, and after re- 
 moval of the slag, is converted into thin plates by 
 throwing water on the surface, and stripping off the 
 chilled metal in crusts or discs of about 1 or 1^ inch 
 thick. After the fire is made up, the first portion of 
 the bloom obtained in the preceding operation is 
 reheated and hammered an operation requiring about 
 an hour and a half. A quantity of from 40 to 70 Ibs. of 
 pig iron, with a little cinder, is then melted down gradu- 
 ally, and upon this the refined metal of the first opera- 
 tion is added by small quantities at a time, until the 
 whole charge forms a more or less pasty or imperfectly 
 fluid mass (sauer) on the hearth bottom, which is 
 broken up with a bar and piled into a heap in the 
 centre. The amount of working depends upon the 
 feel of the iron. If it dries too rapidly, fresh pig iron 
 must be added, while in the opposite case of being too 
 fluid, oxidation is promoted by the addition of hammer 
 scale. The upper portion of the mass, being under the 
 influence of the blast, loses its carbon ; while the lower 
 part, being in contact with the glowing charcoal lining 
 the hearth remains in the condition of cast iron. After 
 making up the pile, the second portion of the previous 
 bloom is reheated, and when this is finished, the con- 
 tents of the hearth, having subsided to a uniform level 
 
408 METALLURGY OF IRO]S. 
 
 surface, are found to be sufficiently fined to allow the 
 formation of a fresh bloom, which is broken out and 
 divided into two parts for further treatment. The 
 half blooms are again divided, and finally finished into 
 bars, which are hardened, broken, and selected in the 
 same way as in Styria. 
 
 It will be seen that the same hearth is, in addition 
 to its proper work, made to do duty alternately as a 
 refinery and reheating fire, an arrangement that must 
 be attended with considerable waste both of time and 
 fuel. The loss upon the pig iron is from 20 to 30 
 per cent., including the reheating ; the consumption 
 of charcoal is from 40 to 50 cubic fact per cwt. About 
 75 per cent, of the produce is good steel, which is 
 reheated in special small fires, and drawn under light 
 hammers into bars, which are packed in cases and sold 
 as Brescian steel. 
 
 The so-called true Brescian process practised at 
 Paal, in Styria, differs in certain details of manipula- 
 tion from the preceding, the most important point 
 being, that in reheating the blooms, they are plunged 
 into the bath of molten pig iron, whereby they undergo 
 a kind of surface hardening by cementation. 
 
 In Siegen, where spiegeleisen is, or was, formerly 
 treated in the open fire, the charge is melted down in 
 small quantities of 60 or 80 Ibs. weight upon a bottom 
 of mettled iron. As soon as fusion commences the slag 
 is tapped to within 2 J inches of the bottom, and further 
 additions of spiegeleisen are made in diminishing quan- 
 tities, from 40 Ibs. at the fifth to 20 Ibs. at the seventh 
 and last charge. It is sought as much as possible TO 
 keep the mass at the consistency of soft butter during 
 the entire operation. The bloom (schrei) ultimately 
 obtained weighs 4 cwt., the time required being about 
 
METHODS OF PRODUCING STEEL. 409 
 
 eight hours. It Is divided into seven or eight pieces, 
 which are tilted into bars, with a loss of about 20 
 per cent. Beckoned upon the pig iron, the loss is 30 
 per cent., 100 Ibs. giving 70 Ibs. of steel, of which 
 about three-fourths are of good quality, and capable of 
 being properly hardened, and the remainder mild steel 
 or steely iron. It is doubtful whether this process is 
 still practised, having latterly been superseded by the 
 method of steel puddling. 
 
 Puddled Steel. There is no essential difference 
 between the methods of making wrought iron and 
 steel in the puddling furnace, other than the degree of 
 decarburisation to which the pig iron is subjected. The 
 most highly-carburised varieties of pig iron, especially 
 those containing manganese, such as spiegeleisen, 
 are best adapted for the process. The furnace is 
 usually of a somewhat smaller size than that employed 
 for making malleable iron ; or rather, the size of the 
 bed is diminished in proportion to that of the fireplace 
 and stack, in order to be able to command a very high 
 temperature. The charge does not usually exceed 3 or 
 3^ cwt., which is introduced in fragments as nearly 
 as possible of the same size and thickness, and spread 
 out so as to expose a large surface to the flame, in 
 order that fusion may be effected uniformly and without 
 much oxidation. The use of only one kind or class of pig 
 iron is also necessary, otherwise, supposing white and 
 grey iron to be mixed, a portion of the charge would 
 probably fine and come to nature while the more 
 fusible part was still unchanged. This is exactly the 
 reverse condition to that required in puddling for 
 malleable iron, where a mixture of two different kinds 
 of pigs has an advantageous effect in accelerating the 
 process. In steel puddling, on the other hand, the 
 
410 METALLURGY OF IRON. 
 
 charge is rendered perfectly fluid, and covered with 
 molten slag, in order that the fining may go on 
 slowly and uniformly. The presence of protoxide of 
 manganese in the slag is important, as contributing 
 fluidity without increasing the decarburising influence. 
 By keeping the contents of the furnace well stirred 
 together during the second part of the process, the 
 iron separated in the malleable condition may, in the 
 event of its becoming too much decarburised, be 
 brought back to the proper condition by dissolving 
 it in the unaltered pig iron below, in a somewhat 
 similar manner to that practised in the Siegen open- 
 fire process, where the iron is prevented from drying 
 to too stiff a consistency by the addition of fresh 
 quantities of pig iron at intervals. In order to induce 
 fining in the molten mass, the damper must be closed 
 until the charge thickens and commences to rise, when 
 the heat must be carefully raised during the time of 
 stirring, which usually takes from thirty-five to forty- 
 five minutes, or somewhat longer than is the case in 
 puddling for malleable iron. The high temperature 
 prevailing in the furnace keeps the contents of the 
 hearth well melted, and by continued stirring, fresh 
 particles of metal are constantly brought to the surface 
 of the fluid covering of slag. The appearance of fine, 
 white, brilliant grains is a sign of the process going on 
 well, and indicates the formation of steel of good 
 quality and uniform texture. If, on the other hand, 
 the separated grains are large, and resemble snow- 
 flakes, the product is likely to be of a coarse fracture, 
 and imperfectly refined. The slag must be less basic 
 than that formed in puddling for malleable iron, as the 
 presence of a large excess of oxides of iron not only 
 
METHODS OF PRODUCING STEEL, 411 
 
 reduces the fluidity, but acts too energetically on the 
 removal of the combined carbon from the pig iron. 
 
 The balling of the granular clots of steel as they 
 come to nature is an operation requiring considerable 
 skill; it must be done in a neutral or non-oxidising 
 atmosphere, such as is obtained by shutting the 
 damper, and keeping the hearth filled with flame and 
 smoke with an ordinary furnace, or shutting off the 
 top blast when a gas furnace is used. The balls are 
 shingled at a lower temperature than those of malleable 
 iron, and when they cannot be immediately taken to 
 the hammer, are protected against oxidation by rolling 
 them in the melted slag, so as to obtain a superficial 
 crust or varnish, which excludes the air from contact 
 with the heated metal. 
 
 The slowness of the fining process, and the extra 
 amount of stirring required, are sufficient to explain 
 the apparent anomaly that a partial should require 
 longer time than a complete decarburisation. Under 
 ordinary circumstances the time required for working 
 off a heat is in either case as follows : 
 
 Fibrous Iron. Steel. 
 
 Melting down . . 30 to 40 minutes 40 to 50 minutes. 
 
 Stirring . ... 30 35 45 50 
 
 Boiling and fining . 25 ,,30 ,, 20 ,,25 ,, 
 Balling .... 10 10 
 
 85 115 105 135 
 
 As originally described in the specification of Eiepe, 
 by whom the process was introduced into England, the 
 charge recommended to be used is 280 Ibs., which is to 
 be exposed to a red heat until the metal begins to fuse, 
 
4 [2 METALLURGY OF IRON. 
 
 when tlie temperature is reduced by lowering the 
 damper. Forge or mill cinder, to the extent of twelve 
 or sixteen shovelsful, is then added, and when the whole 
 was melted, a small quantity of peroxide of manganese 
 salt and clay ground together. After this mixture has 
 acted for a few minutes the damper is fully opened, 
 and about 40 Ibs. of pig iron is placed upon an elevated 
 bed of cinder near the fire-bridge. When this begins to 
 trickle down, and the boiling of the contents of the 
 furnace commences, it is raked into the hearth, and 
 the whole mass is well mixed together. When the 
 grains of steel begin to break through the cinder, as 
 already described, the damper is to be partially closed, 
 and the operation of stirring below the cinder com- 
 menced, taking care that the heat be not raised above 
 cherry redness, or the welding temperature of shear 
 steel. The remainder of the process of balling is done 
 with a closed damper, as already described. 
 
 It appears to be doubtful, according to the state- 
 ments of most of the recent writers on the subject, 
 whether the process can be properly conducted at the 
 low temperature specified. The use of the highest heat 
 attainable in the puddling furnace was afterwards 
 claimed by another patentee, and on subsequent litiga- 
 tion, the term "cherry redness" was explained as mean- 
 ing a bright red heat whe-n the furnace was illuminated 
 by direct sunlight. Parry states that if the heat be 
 too high during the boiling, the mixed cinder and 
 metal separate from each other, and the decarburisation 
 proceeds slowly ; while, on the other hand, if the tem- 
 perature be too low, the cinder and metal cannot be 
 properly mixed, being of too stiff a consistency, and 
 the steel will not be homogeneous. The temperature 
 must be raised to a full yellow heat on the appearance 
 
METHODS OF PRODUCING STEEL. 413 
 
 of the floating granules in the slag. The fire should 
 be made up at the end of the boiling process, in order 
 to prevent the passage of air by opening the fire-hole 
 during the balling. 
 
 It is necessary to shingle the balls as soon as possible, 
 in order to prevent the decarburising action of the rich 
 slag retained by capillary attraction upon the spongy 
 particles of steel. When the slag is poor in protoxide 
 of iron it sets very quickly, and when more basic, acts 
 powerfully in removing carbon. The presence of 
 oxide of manganese is advantageous, as communicating 
 fluidity without increasing the oxidising effect a 
 point of considerable importance, as the shingling 
 takes place at a lower temperature than is the case 
 with malleable iron. In some cases an addition of 
 peroxide of manganese is made immediately before 
 balling, or the mixture of peroxide of manganese, clay, 
 and salt, already mentioned as recommended by Schaf- 
 haiitl for improving ordinary iron, is added at inter- 
 vals after the melting down of the pig iron during the 
 stirring. 
 
 At Lohe, in Siegen, twelve heats of 3-J cwt. of white 
 fibrous " steel " pig iron are puddled in the turn of 
 twelve hours. Each charge yields from seven to eight 
 balls, weighing 40 Ibs. each. The loss upon the pig iron 
 is 9 per cent, in puddling, with a further amount of 11 
 per cent, upon the reheating, which is done in covered 
 hearths with a single twyer, somewhat like the South 
 Wales hollow fire. The blooms are drawn into bars 
 under a tilt hammer. The produce is assorted accord- 
 ing to the fracture : 78 per cent, is good hard steel, 
 capable of being broken when cooled in water ; the 
 remaining 22 per cent, is more or less mixed with soft 
 iron. The total expenditure of coal is double the 
 
414 METALLURGY OF IRON. 
 
 weight of the steel produced : out of this 84 per cent, 
 goes for puddling, and the remaining 16 per cent, for 
 reheating. These quantities refer to Ruhr coal, which 
 is not of a very high quality. The total production 
 for twelve hours is about 34 cwt. 
 
 When grey pig iron is used, either alone or mixed 
 with mottled, it is necessary to add from 10 to 15 per 
 cent, of scale and cinder. In such cases the consump- 
 tion of coal may be somewhat increased, as the process 
 lasts a little longer than when working with iron smelted 
 from spathic ores. In Styrian works using lignite, with 
 the advantage of good pig iron, the consumption is from 
 32 to 42 cwt. per ton of steel blooms made, without 
 counting charcoal and wood for reheating. 
 
 The use of gas furnaces is said to be of great advantage 
 in the steel-puddling process, both as regards saving of 
 fuel and diminishing the waste of iron. At Kirch- 
 hunden, in Siegen, the saving is stated at from 35 to 40 
 per cent, in the coal, and from 9 to 10 per cent, on the 
 amount of iron burnt. According to observations made 
 in several localities, the consumption of fuel is dimi- 
 nished when the sides of the hearth are cooled by a 
 circulation of air instead of water. 
 
 The chemical changes going on in the process of steel 
 puddling have been investigated by Schilling and other 
 chemists in a similar manner to that followed originally 
 by Calvert and Johnson. The following are Schilling's 
 results of the composition of the metal and slag at dif- 
 ferent points of the process, as carried out at Zorge, in 
 Hanover. The charge consisted of white pig iron from 
 Gittelde, and grey from Zorge, mixed in equal weights. 
 The fuel employed in the blast furnace was charcoal, 
 the consumption being at the rate of 100 Ibs. for every 
 87 Ibs of pig iron produced : 
 
METHODS OF PRODUCING STEEL. 
 
 415 
 
 
 
 
 '0 
 
 
 
 
 
 1 ^ 
 
 
 
 
 r-l 
 
 e* 
 
 
 1 
 
 
 
 
 
 
 
 
 3 
 
 1 2 
 
 I 
 
 
 
 b 
 
 b 
 
 b 
 
 
 
 O 
 
 
 
 i 
 
 
 
 CO 
 
 *^1 
 
 J^ 
 
 ) 
 
 1 1 
 
 s 
 
 1 " 
 
 4-3 
 
 
 
 iH 
 
 CO 
 
 P 
 
 
 i 
 
 
 
 
 
 o 
 
 
 
 g 
 
 
 
 
 
 
 
 ro 
 
 
 
 M 
 
 l>- 
 
 
 
 
 I ( 
 
 CO 
 
 *" 
 
 r-l 
 
 
 
 
 o 
 
 o 
 
 M 
 
 1 |j| 
 
 r-* 
 
 b 
 
 b 
 
 b 
 
 b 
 
 
 1 " 
 
 (M 
 
 o 
 
 5 
 
 
 
 r-l 
 
 *J 
 
 
 1 01 
 
 o 
 
 
 
 o 
 
 o 
 
 
 1 5 
 
 CO 
 
 
 -H 
 01 
 
 co 
 
 ^ 
 
 
 
 o 
 
 o 
 
 
 
 o 
 
 
 
 
 
 
 -H 
 
 CO 
 
 I-l 
 
 i 1 CO 
 
 
 ^ 
 
 
 
 
 M 
 
 r-< I 1 
 
 
 
 
 
 ^ 
 
 '~ l 
 
 
 
 C5 
 
 o 
 
 CD 
 
 
 
 CO 
 
 M 
 
 i-l 
 
 
 
 
 
 M 
 
 CNI i 1 
 
 o 
 
 
 
 r ~ l 
 
 r-l 
 
 
 CO O 
 O O 
 
 o 
 
 CO 
 
 
 
 
 
 II 
 
 
 
 
 01 
 
 o 
 
 
 
 o 
 
 cs 
 
 . 
 
 
 
 
 
 
 
 a fl 
 
 
 
 
 
 
 I-l 
 
 
 
 
 
 
 
 
 
 1 g 
 
 
 03 
 
 
 
 
 
 T* 
 
 
 p 
 
 * 
 
 DO 
 
 
 Graphiti 
 Combine 
 
 f-l 
 
 1 
 
 02 
 
 1 
 
 g 
 
 CJ 
 
 1 
 
 
 
 fco 
 
416 
 
 METALLURGY OF IRON. 
 
 The metal of the sample No. III. was tough and strong 
 cast iron ; No. IY., taken after five tools had been heated 
 in rabbling, was stronger than the preceding, but of a 
 tin-white colour ; No. Y. was very cellular, and resembled 
 white pig iron, but was slightly malleable ; No. VI. was 
 decidedly malleable, and apparently possessed most- of 
 the properties of steel, notwithstanding the large amount 
 of carbon present. No increase of carbon was observed 
 in the earlier stages of the process, as recorded by 
 Calvert and Johnson, and Lan. Schilling ascribes 
 this difference to the use of a gas furnace, and the in- 
 troduction of an excess of air into the furnace by the 
 top blast : 
 
 CORRESPONDING COMPOSITION OF SLAGS. 
 
 BLAGS TAKEN WITH 
 
 IV. 
 
 V. 
 
 VI. 
 
 VII. 
 
 VIII. 
 
 IX. 
 
 X. 
 
 Silica 
 
 20-98 
 
 20-51 
 
 2012 
 
 20-34 
 
 20-27 
 
 20-40 
 
 20-52 
 
 Phosphoric acid 
 
 5-25 
 
 5-25 
 
 5-25 
 
 5-25 
 
 5-25 
 
 5-25 
 
 5-25 
 
 Peroxide of iron 
 
 7-12 
 
 4-09 
 
 4-12 
 
 5-20 
 
 5-20 
 
 4-95 
 
 6-24 
 
 Protoxide of iron 
 
 58-98 
 
 62-03 
 
 62-14 
 
 61-20 
 
 61-20 
 
 61-34 
 
 59-88 
 
 Alumina . 
 
 2-78 
 
 2-82 
 
 2-87 
 
 2-87 
 
 2-91 
 
 3-05 
 
 2-86 
 
 Protoxide of ) 
 
 1-64 
 
 T64 
 
 1-64 
 
 1-64 
 
 V64 
 
 1-64 
 
 1-64 
 
 manganese } 
 
 
 
 
 
 
 
 
 Lime 
 
 1-84 
 
 2-14 
 
 2-04 
 
 1-G9; 2-12 
 
 1-72 
 
 1-69 
 
 Magnesia . 
 
 1-62 
 
 1-51 
 
 1-63 
 
 1-52 2-04 
 
 1-81 
 
 1-79 
 
 Alkalies . 
 
 0-93 
 
 0.82 
 
 assumed at 0-87 
 
 Sulphuric acid 
 
 trace 
 
 1 
 
 
 not determii 
 
 led 
 
 
 
 101-14 
 
 100-81 
 
 100-68 
 
 100-58 
 
 101-50 
 
 101-03 
 
 100-74 
 
 In these slags, which are nearly uniform in compo- 
 sition throughout, the oxygen ratio of acid to bases is 
 as 11-687 :. 18*212, or nearly 1 : Ij that of a sesquibasic 
 silicate. This is supposing the peroxide of iron to be 
 in combination with silica, and not replacing it. The 
 large and constant amount of phosphoric acid is ascribed, 
 11 ot to the oxidation of phosphorus contained in the 
 
METHODS OF PRODUCING STEEL. 417 
 
 pig iron, which is obviously in too small a quantity tc 
 produce such an effect, but to the ash of the wood burnt 
 in the gas generator, and carried over by the draught, 
 owing to the defective arrangement of the ash pit. It 
 is evident, therefore, that even the above elaborate 
 series of analyses does not furnish us with an exact 
 idea of the changes going on during the process. 
 
 Production of Steel by Cementation. This process 
 consists essentially in the exposure of bars of malleable 
 iron, in close contact with charcoal, to a high and long- 
 continued heat, the air being excluded. The furnace, 
 Fig. 41, employed for this purpose, is an oblong chamber 
 with a semi- cylindrical roof, containing two large chests 
 or converting pots, a a, also of rectangular form, which 
 are heated by a fire grate, c, placed below them, and 
 running along the entire length of the chamber. The 
 flame is distributed uniformly by a system of transverse 
 rectangular flues, d d, across the bottom and up the 
 sides of the pots, and finally passes through a number 
 of short vertical chimneys in the sides of the chamber 
 into a tall covering hood or stack, c, of conical form, 
 like that of an ordinary glasshouse furnace or potter's 
 kiln. The size of the boxes varies in different localities, 
 according to the weight of iron heated at or>e time, from 
 8 to 15 feet in length, and. from 2J to 3 feet in breadth 
 and height, corresponding to a capacity of between 8 
 and 12 tons of bar iron, with the necessary quantity of 
 cementing powder. In Yorkshire they are usually built 
 of sandstone flags, but in other places ordinary fire- 
 bricks and lumps or slabs of the same material are 
 used. The introduction and withdrawal of the charge 
 are effected through man-holes, b, in the shorter side 
 walls of the covering chambers, placed above the level 
 of the top of the boxes : these holes are of course walled 
 
 T3 
 
418 METALLURGY OF IRON. 
 
 up with, brickwork when the furnace is lighted. Tn 
 some instances, where the furnace is of small size, the 
 roof of the chamber is made in several pieces, so as to 
 
 "Fig. 41. Steel-converting furnace. 
 
 be easily removed at the end of the operation, in order 
 to facilitate the withdrawal of the cemented bars. Two 
 
METHODS OF PRODUCING STEEL. 419 
 
 small square holes, communicating with, the interior of 
 the boxes, are placed a little lower down on the same 
 side of the furnace ; these contain the trial bars used 
 in determining the progress of the conversion. 
 
 Bar iron smelted from Swedish magnetic ores is used 
 in the production of the best kinds of cement steel at 
 Sheffield, and, as a rule, hammered bars are preferred 
 to those made by rolling. The most esteemed brands are 
 those produced at the small forges in the eastern part 
 of Sweden, in connection with the Dannemora mines ; 
 that of Lofsta, known as (L) iron, having the highest 
 reputation. The ordinary sizes of bars employed are from 
 2 to 5 inches in breadth, and from one-third to three- 
 quarters of an inch in thickness ; a flat form being pre- 
 ferred to those of round or square section. In filling 
 the pots, an allowance is made for the expansion of the 
 iron by heat ; a space of about 2 inches in the direction 
 of the length, and a little less transversely, being left 
 between the edges of each layer of bars and the walls, 
 and in like manner the butt ends of adjacent bars in 
 each line must not be brought in contact with one 
 unother. 
 
 The cementing material is in all cases charcoal, in 
 the form of a coarse powder obtained by sifting through 
 a riddle with J or f -inch meshes. No special variety 
 of charcoal is necessary, that of the hardest wood ob- 
 tainable in the neighbourhood being generally us^d ; 
 as, for example, birch in Sweden, beech in Rhenish 
 Prussia, and oak in England. Hard- wood charcoal is 
 said to be advantageous on account of the large amount 
 of alkaline salts in the ash, which are regarded as 
 favouring the production of cyanogen compounds. For 
 the same purpose, an addition to the charcoal of small 
 quantities of carbonate of baryta, alkaline carbonates, 
 
420 METALLURGY OF IRON. 
 
 yellow prussiate of potash, animal charcoal, or organic 
 matter containing nitrogen, has been recommended at 
 different times, and tried experimentally ; but none of 
 these substances are in general use, except in the super- 
 ficial converting process of case-hardening. 
 
 In charging the pots, the bottom is first covered with 
 a coating of charcoal, and upon it the bars are arranged 
 in tiers lying on the flat sides, and separated from each 
 other by a layer of charcoal about half an inch thick. 
 About one- third of the total cubic contents of the pot is 
 occupied by the iron, the remaining two-thirds being 
 filled with charcoal. When the whole charge has been 
 introduced, the top of the pot is covered with a layer 
 of clay or other refractory material. At Sheffield, 
 grinder's waste, or wheelswarf a mixture of finely- 
 divided, partially-rusted steel with quartzose sand, 
 produced by the waste of the grindstones employed in 
 grinding 'cutlery is generally used. It is plastered 
 over in a damp state, and frits together to a kind of 
 glaze when strongly heated, forming a covering im- 
 pervious to the air. A certain proportion of fresh 
 charcoal, to the extent of one-half or two-thirds of the 
 total quantity, must be used in each operation ; that 
 remaining from a former charge requires to be subjected 
 to washing and sifting before it can be used again. The 
 mixture of the two kinds is found to give a better result 
 than when fresh coal is used alone, and the conversion 
 ie more rapidly effected. 
 
 When the furnace is charged, all the apertures are 
 carefully stopped with brickwork or fire-cla^, to prevent 
 the access of air. The fire is then lighted, and in about 
 twenty-four hours the chests are raised to a red heat, 
 and in about two or three days more will have attained 
 the proper temperature. According to the nature of 
 
METHODS OF PRODUCING STEEL. 421 
 
 the steel required, the fire is kept up for a period of 
 from seven to nine or eleven days ; the hardest quality 
 for melting purposes requiring the longest, and spring 
 and shear steel the shorter time. Conversion begins at 
 a temperature of about 1,000, but goes on more actively 
 at the melting point of copper, about 1,170: at higher 
 temperatures cast iron is produced. 
 
 The progress of the conversion is determined by the 
 appearance of the trial bar ; the first is taken out after 
 about a week's firing. When there is no longer an un- 
 altered kernel of soft iron apparent in the centre, the 
 conversion is considered to be complete, the fire is allowed 
 to go down, and the furnace is left to cool for three 
 days ; the man-hole stoppings are then removed, and on 
 the sixth day the withdrawal of the cemented bars is 
 commenced, and takes one or two days more, so that the 
 whole operation requires from seventeen to twenty 
 days; Tho physical properties of the iron are con- 
 siderably modified by conversion ; the colour of the 
 fractured surface changes from the original bluish 
 tinge of malleable iron to a somewhat reddish white, 
 like that of bismuth, and at the same time the lustre 
 is considerably diminished. The texture is in all cases 
 scaly crystalline. The finer the grain and the darker 
 the colour, as a general rule, the more highly carbu- 
 rised or harder will be the steel produced ; at the same 
 time, both specific gravity and tenacity are reduced. 
 A more decided peculiarity of the converted bars, how- 
 ever, is the blistering of the external surfaces, whence 
 the term blister steel is derived. When the blisters are 
 small, and tolerably regularly distributed, the steel is 
 of good quality ; but when large, and only occurring 
 along particular lines, they may be considered as indi- 
 cative of defective composition or want of homogeneity 
 
122 METALLURGY OF IKON. 
 
 in the iron employed. The cause of this phenomenon 
 is not quite clearly made out. The most probable 
 explanation is, that it is due to the irregular action of 
 the cementing material upon included particles of slag, 
 consisting of basic protosilicate of iron, which is re- 
 duced to the metallic state with the evolution of car- 
 bonic oxide, which blows up the surface of the metal 
 when in a softened condition from the heat of the 
 furnace. The average increase of weight in the con- 
 version of bar iron into blistered steel is from 1 to 
 f per cent. The fuel necessary per 100 Ibs. of the 
 latter is as follows : 
 
 Coal ....:. 75 to 90 Ibs. 
 
 Lignite ..'... 160 ., 210 
 Peat ...... 200 300 
 
 Wood 300 
 
 Blister-steel bars may bo used for common purposes, 
 such as steeling the faces of hammers, without further 
 treatment ; but more generally they are subjected to 
 one or more reheatings in packets or faggots, and 
 weldings by hammering or rolling, whereby the texture 
 becomes more uniform, and strength and elasticity are 
 increased, but with a progressive diminution of hard- 
 ness. Spring steel is produced by heating blistered 
 bars at an orange-red heat, and drawing them down 
 either under the hammer or by rolling. Shear steel is 
 a better quality, obtained by drawing the original bars 
 to lengths of 3 feet, which are piled together in faggots 
 and welded, the reheating being effected in a hollow 
 fire. The surface of the faggot is covered with clay, 
 which forms a cinder in the heating process, and 
 prevents the blast from acting on the combined carbon 
 of the crude bars. The product of this operation is 
 
METHODS OF PRODUCING STEEL. 423 
 
 known as single shear. It may be further refined by 
 doubling the bars, and repeating the process of heating 
 and welding, making double-shear steel. The best and 
 most uniform quality of steel can, however, only be 
 obtained by fusing the blistered bars in crucibles a 
 process that will be noticed further in page 354. 
 
 Case-hardening, or the production of a thin super- 
 ficial layer of steel upon malleable iron, is a rapid 
 process of cementation carried out on a small scale. An 
 iron box, heated in a smith's forge, is used as a 
 cementation chest. The charcoal is usually obtained 
 by carbonising animal matter, such as bones, horn, or 
 leather. The articles to be case-hardened are embedded 
 in the charcoal in the ordinary way, and are then exposed 
 to heat for a short time, taking care not to use too high 
 a temperature. Under the most favourable circum- 
 stances the cemented layer may attain a depth of about 
 three- eighths of an inch in four or five hours. The 
 work, when removed from the fire, is hardened by plung- 
 ing it while in a heated state into cold water, if it is re- 
 quired to be uniformly hard over the whole surface, 
 otherwise it is allowed to cool, and the steeled surface 
 is removed by turning down such parts as are intended 
 to remain malleable, and the other portion is sub- 
 sequently hardened by heating and quenching in water 
 as before. 
 
 The following is the most rapid method of case- 
 hardening : The piece of iron to be treated, after being 
 polished, is raised to a bright red heat, and the surface 
 to be hardened is rubbed or sprinkled with finely- 
 powdered yellow prussiate (ferrocyanide of potassium). 
 As soon as the powder has volatilised or disappeared, 
 the work is quenched in cold water in the usual -way. 
 If the process has been properly conducted, the sur- 
 
424 METALLURGY OF IRON. 
 
 faces covered by the salt will be found to have become 
 hard enough to resist the file. 
 
 Malleable Cast Iron. The process of annealing, or 
 rendering the surface of cast-iron articles malleable, so 
 that they may be filed or hammered, is a kind of inverse 
 cementation, finely-divided peroxide of iron being em- 
 ployed to remove the carbon from the surface of the 
 casting. Cast iron smelted from red hematite is gene- 
 rally preferred for this purpose, especially that made 
 with charcoal. The fusion takes place in crucibles in an 
 ordinary air furnace, such as is used for smelting cast 
 steel, coke being employed as fuel. The castings, when 
 removed from the moulds, are very brittle, and cannot 
 be touched with the file. They are then packed in cast- 
 iron crucibles containing powdered red hematite, which 
 are arranged in rows one above another in a furnace of 
 rectangular section, somewhat similar in character to 
 an ordinary cementation chamber. When the furnace 
 is charged, all the apertures are carefully closed, and 
 heat is applied gradually, so that the whole contents 
 may be brought up to a red heat in twenty-four hours ; 
 the firing is then continued for from three to five days 
 more, according to the depth of the malleable skin 
 required on the finished work. Articles of irregular 
 thickness that are intended to be bored out must be 
 subjected to t'he process a second time, in order to 
 obtain the proper degree of alteration. 
 
 The appearance of the finished articles, when drawn 
 from the furnace, is similar to that of malleable iron, 
 but lighter in colour ; the density is about the same as 
 cast iron, the increased specific gravity of the malleable 
 portion being counteracted by its porosity. The frac- 
 tured surface is white and finely granular, with a very 
 high lustre, occasionally presenting a grey silky ap- 
 
METHODS OF PRODUCING STEEL. 425 
 
 pearance, recalling that of soft steel. "When the thick- 
 ness of the object is more than half or two-thirds of an 
 inch, a kernel of very soft grey cast iron is left in the 
 centre. In the latter case the central portion may some- 
 times be broken by bending the object without the 
 external skin giving way. 
 
 Malleable castings, prepared in the above manner, 
 may be easily wrought cold, but become very brittle 
 when heated., breaking to pieces under the hammer at an 
 incipient white heat ; at a higher temperature the kernel 
 of unaltered cast iron melts, so that articles that have 
 been subjected to the process cannot be united by weld- 
 ing, but may be brazed without difficulty. On account 
 of the more refractory nature of the material, the use 
 of malleable cast-iron crucibles has been suggested for 
 melting silver in mints, instead of the cast-iron pots 
 ordinarily used for that purpose. 
 
 The principal application of the process is, however, to 
 small articles of hardware, such as keys, buckles, gun fur- 
 niture, &c. Recently, however, it has been applied on 
 a larger scale by M'Haffie, of Glasgow, to parts of 
 machinery, such as toothed wheels and screw pro- 
 pellers, the latter having been successfully adopted in 
 steamers employed in the whaling and sealing trade in 
 the Greenland seas, where ordinary cast-iron screws 
 are especially liable to be broken by the floating ice. 
 
 The malleable skin may be partially converted into 
 steel by case-hardening in the same way as ordinary 
 soft iron, so that these different states of cast iron, 
 malleable iron, and steel may be combined in the same 
 object. Common articles of cutlery made in this way 
 are distinguished as run-steel goods. 
 
 Production of Steel by Fusion. In all the preceding 
 methods, the steel produced, whether by fining or 
 
426 METALLURGY OF IRON. 
 
 cementation, is, as a rule, very unequal in quality ; and 
 uniformitj- can only be attained by repeated faggoting 
 and welding, steps which are necessarily attended 
 with a loss of carbon, and consequent reduction of 
 hardness. The requisite uniformity of composition 
 may, however, be obtained by breaking up the crude 
 bars produced in the forge, or by cementation, and 
 exposing them to a strong heat in crucibles out of 
 contact with the air. The product, when melted, is 
 poured out into cast-iron moulds, forming ingots of 
 cast stecl t which are much more regular in composition 
 and texture than the original material. 
 
 The practice of melting steel was introduced at 
 Sheffield by Huntsman about the year 1740, and is still 
 carried out in substantially the same manner at the 
 present day. Although a simple operation, it is an ex- 
 pensive process, owing to the large consumption of fuel 
 and crucibles required for a comparatively small produc- 
 tion of ingots, 
 
 The general arrangements of a steel-melting house 
 are shown in the transverse section, Fig. 42. 
 
 The furnace, or melting hole, a, is a small square or 
 oblong chamber, about 3 feet deep, from li to 2 feet 
 square, lined with refractory materials, such as fire- 
 brick or the siliceous stone known as ganister. The 
 top of the'furnace is placed level with the floor of the 
 casting house, the grate bars and ash-pit being acces- 
 sible through a vaulted cellar, b, below. The cover of 
 the furnace is a square or quarry of fire-brick set in an 
 iron frame with a projecting handle. There is a short 
 lateral flue near the top of the furnace, communicating 
 with the stack, which is nearly of the same sectional 
 area as the furnace, and about 40 feet high, in order 
 to command a strong draught. Several furnaces are 
 
METHODS OF PRODUCING STEEL. 
 
 427 
 
 usually arranged in longitudinal series on opposite sides 
 of the casting house, leaving the centre of the floor 
 clear for placing the moulds. 
 
 The crucibles used are made of mixtures of different 
 
 42. Cast-steel melting furnace. 
 
 kinds of fire-clay from the coal measures, with a certain 
 proportion of ground potsherds and ccke dust ; the usual 
 size is from 16 to 18 inches in height, and from 5 to 7 
 inches in diameter at the mouth, with a slight belly 
 at about two-thirds of the height from the bottom. 
 
42 S METALLURGY OF IRON. 
 
 The capacity varies from 35 to 80 Ibs. Usually two 
 pots are placed in a furnace : they stand upon cylin- 
 drical discs or cheeses of fire-brick resting on the grate 
 bars. Previously to being used they require to be 
 gradually heated to redness in an open fire or annealing 
 grate, c, which is done by placing them in batches of 
 twenty, bottom upwards, together with their covers, 
 upon a bed of red-hot coal in the grate ; and the inter- 
 mediate space is then filled with coke, and the fire is 
 urged until the necessary heat has been obtained. The 
 pots are then removed to the melting furnaces, and fixed 
 in position on their stands. The fires are replenished 
 with coke, and as soon as they have been brought up to 
 a strong heat, which takes place in about twenty minutes, 
 the charge of blister steel, properly assorted and broken 
 into small pieces, is introduced through a wrought-iron 
 funnel ; after which the cover is placed on the top of 
 the pot, and the full heat of the furnace is given for 
 about three and a half hours, during which time 
 fresh fuel must be added every three-quarters of an 
 hour. "When the fusion is complete, which is ascer- 
 tained by removing the cover and searching the con- 
 tents of the crucible with a pointed rod, in order to 
 ascertain whether any hard unmelted lumps remain, the 
 crucible is cleared from adherent slaggy masses by 
 stirring below the grate, and is then lifted out by the 
 furnaceman with a pair of curved-nosed tongs. The 
 ingot mould, made of cast iron, is blackened by coating 
 it with train oil and heating ; or, in some cases, a thm 
 wash of fire-clay, mixed with water to the consistency 
 jf cream, is used. When the pot is removed from the 
 furnace it is deposited in the teaming hole, d, a small 
 pit filled with broken pieces of coke, and the lifting 
 bags are changed for those used in casting. The con- 
 
METHODS OF PRODUCING STEEL. 429 
 
 tents of the crucible are allowed to cool for a short time 
 before pouring. When the ingot mould is filled, its 
 mouth is covered with a plug of cast or wrought iron, 
 01 a shovelful of sand, in order to prevent the top of 
 the ingot from becoming spongy by the escape of gases 
 before solidification. 
 
 After the first cast the crucible is cleared from 
 adherent clinker, and returned to the furnace for a 
 second melting. The charge is somewhat reduced, and 
 the consumption of coke, as well as the time of fusion, 
 is diminished in a similar proportion. Thus the first 
 melting takes from four to six hours, while the second 
 and third only require from two to two and a half hours 
 each. The furnace is allowed to cool after from three 
 to five meltings have been made, as there is no advantage 
 to be gained by keeping it constantly heated, owing to 
 the corrosion of the lining bricks produced by the very 
 high temperature, whereby the capacity and power of 
 consuming fuel is increased, without a corresponding 
 increase in the amount of steel melted. 
 
 Under ordinary circumstances, the total amount of 
 coke burnt is from three to three and a half times the 
 weight of the ingots produced, when of a good quality ; 
 but when made from inferior varieties of coal, it may 
 be as high as five or six times the weight. 
 
 In France furnaces are used capable of containing a 
 large number of crucibles which are not brought into 
 direct contact with the fuel, but are arranged in series 
 in a chamber, which is heated by a fireplace similar to 
 that of a reverberatory furnace. The chambers, which 
 are made to hold from four to nine pots, are covered 
 with a square lid in the usual way. In addition to the 
 chimney draught, a blast is used below the grate, and 
 a portion of the waste heat is sometimes applied to 
 
430 
 
 METALLURGY OF IRON. 
 
 raising steam for the hammers and rolling mills used 
 in finishing the ingots. Siemens' regenerative gas fur- 
 nace has also been applied with considerable advantage 
 to steel melting, and by its use the consumption of fuel 
 per ton is reduced from 3J tons of coke to 1J tons of 
 
 
 Fig. 43. Siemens' cast-steel furnace. Section through melting chamber 
 and regenerators. 
 
 inferior slack. The arrangement, which is somewhat 
 similar to that of the regenerative puddling furnace 
 already noticed, is shown in Fig. 43, where the pots, 
 placed in four series of eight each in the chamber, are 
 
 Fig. 44. Siemens' cast-steel furnace. Plan of Sues. 
 
 heated by the combustion of gas and air, which have 
 been previously raised to a very high temperature by 
 
METHODS OF PRODUCING STEEL. 431 
 
 their passage through the left-hand pair of regene- 
 rators, b c, the excess of heat carried out of the melting 
 chamber being absorbed by the brickwork in the right- 
 hand pair, d e. "When the latter have become heated 
 as the former cools, the current is reversed by turning 
 the valves, admitting the air and gas into the position 
 shown by the dotted lines in the section, Fig. 44. The 
 course of the two currents is shown by the arrows. 
 The spent gases, after giving up their surplus heat, 
 escape by the chimney at/. 
 
 When very large masses of cast steel are required, 
 the contents of all the crucibles are either poured into 
 a foundry ladle before filling the mould, or the pouring 
 is so arranged that by bringing up relays of fresl? 
 pots, a constant stream may be kept up without inter- 
 mission. In this way large castings, up to as much as 
 40 tons, are made by Krupp, in Essen, from crucibles 
 containing 70 Ibs. of steel. The furnaces hold from 2 
 to 24 pots each. The materials used are reported to 
 be puddled steel and wrought-iron scrap, with an addi- 
 tion of carbonaceous matter, in order to render the 
 malleable iron fusible, a somewhat similar process to 
 that adopted in making the native Indian steel called 
 wootz. 
 
 The drawing of the crucibles from the furnace is 
 also facilitated by placing them on a platform, which is 
 raised by a mechanical lifting apparatus placed below 
 the ash-pit, thus doing away with the use of lifting 
 tongs. 
 
 At the River Don Steel "Works, in Sheffield, cast 
 steel is largely made by the method introduced by 
 Mushet in 1801, which consists in melting malleable 
 scrap iron with charcoal and oxide of manganese in 
 crucibles directly, without using any blister steel. The 
 
4:32 METALLURGY OF IRON. 
 
 furnaces are 288 In number, each of sufficient size to 
 contain two pots charged with 100 Ibs. With the 
 whole number at work, a casting of 25 tons' weigh-, 
 may be made, the pouring from the 576 pots being 
 completed in five minutes. In order to keep up the 
 supply, the pots are conveyed from their melting holes 
 to the casting place on small barrows, instead of being 
 carried by the tongs, as was formerly the custom. The 
 steel produced is to a great extent employed in making 
 castings for direct use, such as railway crossings, 
 wheels, and bells, instead of merely running it into 
 ingots, which are subsequently worked up under the 
 hammer. The moulds used for this purpose are made 
 sufficiently refractory by the use of a thin layer of 
 burnt clay, produced by grinding old melting pots, 
 which is applied immediately over the pattern, the 
 remainder of the box being filled with ordinary moulding 
 sand. This method of steel casting was first practised 
 at Bochum, in Westphalia, where it is still carried out 
 on a very large scale. Castings made to pattern, which 
 are not intended to be subsequently hammered, must 
 be annealed and allowed to cool very slowly. 
 
 An addition of manganese, either as a carburet 
 reduced by heating the oxide with carbon at a very 
 high temperature, or a mixture of black oxide of man- 
 ganese with carbonised pitch or resin, is very commonly 
 used for improving steel in the process of melting. 
 This is the celebrated process of Heath, which formed 
 the subject of long and protracted litigation a few 
 years back. 
 
 The appearance of the fracture surfaces of ingots of 
 cast steel varies with their hardness or relative pro- 
 portion of carbon. The softer kinds are bright and 
 finely granular. The harder qualities often show 
 
METHODS OF PRODUCING STEEL. 433 
 
 crystalline plates of a certain size, arranged in parallel 
 stripes or columns at right angles to the surface of the 
 mould, so that in a square ingot the columns intersect, 
 forming a cross. In all cases the ingots are more or less 
 unsound, being filled with small vesicular cavities, so that 
 they require to be reheated and hammered before they 
 can be converted into bars. This is done in the manner 
 already described for making shear steel, care being 
 taken to effect the reheating at as low a temperature 
 as possible, and to prevent the metal from burning 
 by keeping it out of access of the air while in the 
 fire. 
 
 Bessemer* s Process. This, one of the simplest methods 
 of producing cast steel in large quantities, combines 
 the action of the puddling and ordinary steel-melting 
 furnace into one operation. The essence of the process 
 consists in injecting large quantities of air into a bath 
 of molten cast iron through a large number of small 
 orifices, in order that the combustion of the carbon and 
 other matters in combination may take place rapidly 
 and uniformly. By this means a very high tempera- 
 ture is developed in the converting vessel, the heat 
 being sufficient to melt the decarburised malleable iron, 
 instead of producing it in a pasty, weldable condition, 
 as is the case in the puddling furnace. This great in- 
 crease of temperature is obviously due to the rapidity of 
 combustion, owing to the intimate contact of the air, 
 vhich is injected at a much higher pressure, from 15 
 to 20 Ibs. to the square inch, than is used in the 
 ordinary operation of iron-melting, with the molten 
 metal, instead of the decarburised iron merely taking 
 place at the surface of the bath, or where the pasty 
 metal is in contact with particles of scale, cinder, or 
 similar oxidising agents, as is the case in puddling. It 
 
 u 
 
4:34 METALLURGY OF IRON. 
 
 will be remembered that, in the latter process, the 
 temperature of the puddling furnace has to be artifi- 
 cially reduced by closing the damper, in order to bring 
 about the reactions between the different portions 
 of the charge, which only go on very slowly when the 
 contents of the hearth are in a liquid state. In Besse- 
 mer's process, however, the increase of temperature 
 goes on progressively from the moment the blowing 
 commences until the conclusion of the operation, the 
 heat produced being developed by combustion going 
 on in the molten mass, in the order in which the com- 
 bined foreign substances are removed being similar to 
 that observed in puddling and reiining. After the 
 whole of the carbon has been eliminated, the heat is 
 kept up, if the blowing be prolonged by the combus- 
 tion of the iron, giving a product exactly similar in 
 general properties to the burnt iron which is obtained 
 when malleable iron is too often or too highly heated 
 in the process of welding. 
 
 This process is, therefore, not adapted for the pro- 
 duction of soft malleable iron, but, with certain 
 modifications, is capable of producing steel of good 
 quality, within a considerable range of > composition 
 and hardness. This may be done in two ways : the 
 first is that practised in Sweden, where the blowing is 
 interrrupted after partial decarburisation of the charge, 
 the proper moment for stopping the operation being de- 
 termined by the appearance of the flame issuing from 
 the mouth of the converting vessel; or the metal 
 may be completely decarburised, and then brought 
 back to the composition of steel by the addition ol 
 highly-carburised melted pig iron, such as spiegeleisen, 
 in sufficient quantity to restore the necessary amount 
 cf carbon. The latter modification of the process is 
 
METHODS OF PRODUCING STEEL. 435 
 
 duo to Mushet, and is now generally preferred to the 
 older method, as being more certain in result. 
 
 The varieties of cast iron best adapted for conversion 
 into steel by the Bessemer process are those smelted 
 from hematite or magnetic ores not below No. 2 in 
 greyness. White iron can only be treated with diffi- 
 culty and increased waste, partly owing to its imper- 
 fect fluidity when melted, which increases the resistance 
 oifered to the passage of the blast, but more particularly 
 on account of its deficiency in carbon and silicon. The 
 carbon being in the combined state, the production of 
 carbonic oxide takes place at too early a stage of the 
 process, and not being present in sufficient quantity, 
 prevents the attainment of the proper temperature in 
 the converting vessel. 
 
 The chief essentials in the chemical composition of 
 the pig iron are, almost absolute freedom from sulphur, 
 phosphorus, and copper, as neither of these ingredients 
 is sensibly reduced in amount by the process ; silicon 
 and manganese, on the other hand, may be almost com- 
 pletely removed, and their presence is beneficial within 
 certain limits. As long as manganese remains scarcely 
 any iron is oxidised, the silica produced from the silicon 
 of the metal uniting with protoxide of manganese to 
 form a slag, which is very fluid, but also is very 
 destructive to the siliceous linings of the converting 
 vessels. 
 
 The best English pig iron for use in the Bessemer 
 process is that smelted from Cumberland hematite, about 
 No. 1 or No. 2 in greyness. It should contain from 1J 
 to 2 per cent, of silicon as a minimum, and not more than 
 O2 per cent, of phosphorus. At Essen, in Westphalia, 
 the limiting quantities of foreign matters in the pig 
 iron preferred for Bessemer steel-making are as follows, 
 
436 METALLURGY OF IKON. 
 
 according to Jordan. The metal generally used is 
 smelted from mixtures of spathic ore and Nassau 
 hematite. 
 
 Manganese, maximum 1-00 per cent. 
 
 Sulphur -04 
 
 Phosphorus -06 ,, 
 
 Carhon minimum 5'00 ,, 
 
 Silicon 2-00 ,, 
 
 The furnaces, or converters, employed in the process 
 are of two different kinds. The oldest, or fixed form, 
 which has been used to a certain extent in Sweden, is a 
 cylindrical vessel of refractory brickwork, somewhat 
 similar to a foundry cupola, but broader and lower in 
 proportion. Near the bottom, which is made with a 
 slightly forward incline towards the tap hole, is placed 
 a series of small twyers, which are arranged at equal 
 distances around the entire circumference. The top 
 of the vessel is covered by a dome, terminating in a 
 conical neck, turned towards a hood placed above it, for 
 carrying off the flame and sparks given out during the 
 blowing. 
 
 T.He second, or movable, form of converter, which is 
 now almost universally adopted, consists of an egg- or 
 pear-shaped vessel suspended upon trunnions, and pro- 
 vided with appropriate moving mechanism, whereby it 
 may be rotated vertically through an angle of about 
 180. The outer casing or shell is made of wrought- 
 iron plates riveted together, and, as originally made, 
 was not unlike a soda-water bottle in shape, supposing 
 the pointed end to be flattened, and the neck turned 
 over at an angle of about 30 to the body. In the newei 
 forms, however, especially those intended for working 
 with large charges, increased capacity is obtained by 
 
METHODS OF PRODUCING STEEL 
 
 437 
 
 making the body and lower part cylindrical, tnus ap- 
 proximating in outline to the older fixed converters, 
 as in Fig. 45. 
 
 The suspension is effected by means of a stout hoop 
 of wrought iron or steel carrying two trunnions, which 
 is shrunk on to the body of the converter at the widest 
 part. One of these trunnions, which run in bearings 
 
 Fig. 45. Bessemer'a steel converter. 
 
 A. Transverse section through trunnions. 
 
 B. Bottom plan. 
 
 0. Section of twyer brick. D. Plan of ditto. 
 
 supported by cast-iron standards, is solid, while the 
 other is hollow, forming a passage for the blast, and 
 carries a spur pinion. 
 
 The interior lining of the converter must be made of 
 the most refractory material obtainable. Fire-brick or 
 
438 METALLURGY OF IRON. 
 
 clay may be used ; but in Sheffield, and in England 
 generally, a nearly pure siliceous sandstone from below 
 the coal measures, known as ganister, is found to be 
 better adapted for this purpose than any other sub- 
 stance. It is prepared by grinding to a fine powder, and 
 may be used alone or mixed with a certain proportion 
 of powdered fire-brick ; in either case a small quantity 
 of water is used, sufficient to make the powder slightly 
 coherent, which is then rammed hard between the 
 inside of the shell and a wooden core, which is after- 
 wards removed. The old form of vessel is made in 
 two parts, which are united by screw bolts, and can be 
 taken apart for convenience in lining. In the cylin- 
 drical-bodied form, the lower part is made removable, 
 the Union being effected by eye-bolts and cotters. 
 
 The bottom of the converter is in either case flat, 
 and contains the twyer box. This is a cylindrical 
 chamber, connected by a curved pipe with the hollow 
 trunnion. The twyers are cylindrical or slightly tapered 
 fire-bricks, each perforated by seven parallel holes, 
 about half an inch in diameter. Usually from five to 
 seven of these bricks are used, which are arranged ver- 
 tically and at equal distances apart in the lining of the 
 bottom of -the converter. Their lower ends pass through 
 a perforated guard plate in the top of the air chamber, 
 the vertical position being maintained by stops bearing 
 against horizontal arms, which may be turnad on one 
 side, when it is necessary to remove or replace the 
 bricks, without being obliged to take out the bottom of 
 the converter. 
 
 The mechanism for turning the converter about its 
 axis is of a simple character, consisting of a direct- 
 acting water-pressure engine, whose piston rod carries 
 a rack gearing into tho pinion on the trunnion. At 
 
METHODS OF PRODUCING STEEL. 439 
 
 first the cylinder was placed "horizontally, but in the 
 newer form of construction a vertical position is 
 generally preferred, as it occupies less ground space. 
 The engine is double-acting, the valve being worked 
 by hand gear placed at a distance. 
 
 In the earlier Bessemer works two converters are 
 placed opposite to each other with a deep cylin- 
 drical casting pit between them. In tho centre of 
 the. pit is fixed another water- pressure engine, with 
 a vertical cylinder and solid plunger piston, carrying 
 lit its upper end a cross arm, formed of two parallel 
 girders strongly braced together, to one end of which 
 is attached the ladle, the overhanging weight being 
 supported by a counterpoise attached to the opposite 
 end. The ladle, which is similar to that used by iron 
 founders, but considerably larger, is made of wrought 
 iron lined with fire-clay, having a small hole in the 
 bottom for running out the melted steel into the ingot 
 moulds placed below. The hole is closed by an iron 
 rod coated with fire-clay. The opposite end of the rod 
 passes through a slide bar on the outside of the ladle, 
 and may be raised or lowered by means of a hand lever. 
 In order to traverse the ladle about the central pillar, 
 so as to bring the centre of the hole over each of the 
 moulds in succession, the top platform is provided with 
 spur gearing, so that it may be moved like a railway 
 turn-table. This motion is worked by a man standing 
 on the platform, as is also another for reversing the 
 ladle on its bearings, in order to remove the waste 
 after the end of the cast. The valve of the central 
 engine, which raises and lowers the ladle, is in charge 
 of the same man who works the tipping engines for 
 the converters. lie is usually stationed in a box at one 
 side of the converting house, raised a sufficient height 
 
440 METALLURGY OF IRON. 
 
 above the ground to command a clear view of the whole 
 of the apparatus. The power for working the engines 
 is obtained from a small steam engine driving the 
 necessary force pumps, which deliver their supply into 
 two accumulators for equalising the pressure. 
 
 The arrangements alluded to in the preceding para- 
 graph are represented in elevation in Fig. 46. a a are 
 the two converters, each capable of holding 3 tons 
 of molten pig iron ; that on the right-hand side is 
 lowered for filling, while the other is upright and in 
 the position for blowing, the flame rising from the 
 neck being carried into the chimney by the wrought- 
 iron hood/, b b are the two hydraulic engines work- 
 ing the tipping gear, c is the central crane carrying 
 the ladle. The cylinder, which is sunk below the level 
 of the bottom of the casting pit, is only partly repre- 
 sented. The horizontal racked rod gearing into a 
 pinion on the ladle is a slow- motion adjustment for 
 bringing the hole through which the steel issues im- 
 mediately over the centre of the mould. It is worked 
 by a tangent screw from a handle attached to the 
 platform carrying the ladle. The traversing motion, 
 consisting of a small pinion gearing into a large fixed 
 spur wheel on the central pillar is worked by a hand 
 wheel, also on the platform, the two handles being 
 placed close together, so as to be within reach of the 
 workman superintending the casting, d d are cranes 
 employed for removing the ingots from the casting 
 pits. They are similar in general construction to that 
 last described, being lifted and turned by hydraulic 
 pressure, e is the box containing the valve handles of 
 the various engines. The central hand wheel governs 
 the vertical motion of the casting crane, while the 
 outer ones are in connection with the tipping engines 
 
METHODS 0V PRODUCING STEEL. 441 
 
442 METALLURGY OF IRON. 
 
 of the converters. The more important of the newer 
 arrangements are described on page 455. 
 
 The method of conducting the process is as follows : 
 The charge of pig iron, which may be of any weight 
 between 1| and 10 tons 3 to 8 tons are now generally 
 used in preference to the smaller weights is melted 
 in a cupola, or brought melted in a ladle from the blast 
 furnace. The converter, having been previously brought 
 *ap to a red heat by filling it with ignited coke, is reversed 
 in order to remove any unconsumed fuel, and after- 
 wards turned back to a horizontal position, to receive 
 the charge of molten metal, which is run in through 
 a movable gutter of wrought iron lined with sand. It 
 is then slowly brought back to the vertical position, 
 and the blast is turned on. At first the flame issuing 
 from the neck is of a yellowish or reddish colour, but 
 slightly luminous, with only a comparatively small 
 amount of sparks. During- this period, lasting from 
 four to six minutes, the action going on is similar to 
 that in the refinery in the first stage of puddling, 
 namely, the conversion of graphitic into combined 
 carbon, and the oxidation of silicon, with the formation 
 of a silicate" of protoxide of iron and manganese. In 
 the second or boiling period, when the oxygen of the 
 blast begins to attack the carbon, the action becomes 
 very violent, the flame increases in brilliancy, and 
 great showers of sparks, fragments of burning iron, 
 and finely-divided slag are thrown out, owing to the 
 rapid ebullition produced by the evolution of carbonic 
 oxide from all parts cf the melted metal. This lasts for 
 about six or eight minutes longer, when the sparks 
 diminish and the action goes on more quietly without 
 the production of sparks. The flame gives the cha- 
 
METHODS OF PRODUCING STEEL. 443 
 
 rncteristic bluish violet of carbonic oxide, and is in- 
 tensely hot a point marking the last or fining stage. 
 When the last trace of carbon is burnt away, the 
 flame suddenly drops, and is succeeded by a stream of 
 luminous white-hot gas, consisting principally of nitro- 
 gen, the heat being kept up from this moment, if the 
 blowing be continued, entirely by the combustion of 
 the molten decarburised iron. As soon, however, as 
 the flame indicates that the whole of the carbon is 
 removed, the converter is turned back to the horizontal 
 position, and the proper quantity, usually about 10 per 
 cent., of molten spiegeleisen, or other similar compound 
 of iron, carbon, and manganese, is* run in from the air 
 furnace in the same manner as the original charge. 
 Formerly the blowing was resumed for a few minutes 
 after addition of the spiegeleisen, but this is now 
 discontinued, and tho contents of the converter are 
 emptied into the ladle, which has been brought into 
 the proper position by lowering the central pillar of 
 tho crane. The ingot moulds usually employed are 
 made of cast iron, open at both ends, of an octa-pcnal 
 or circular form of base, and somewhat smaller i'l 
 diameter at the top than the bottom. They are 
 arranged in a semicircle on the floor of the casting 
 pit. The ladle is raised to a sufficient height to 
 clear the top of the moulds, and is turned so as 
 to bring the hole over the centre of each one suc- 
 cessively ; the plug is lifted, and tho molten steel 
 flows out in a stream about an inch thick. Care 
 must be taken to prevent the stream from striking 
 against the side of the mould, in which case the ingot 
 i's likely to be unsound. When the mould is filled a 
 email quantity of sand is thrown on the surface of the 
 metal, which is then covered by a piece of thin sheet 
 
444 METALLURGY OF IRON. 
 
 iron, and the whole is secured by a cross bar passing 
 through two eyes on the top of the mould. 
 
 After the converter is charged, the blast must be 
 admitted before it is turned back to the vertical posi- 
 tion, otherwise the molten metal would run down 
 through the twyers. A pressure of from 5 to 6 Ibs. 
 per square inch is required to overcome the hydraulic 
 head of the liquid column of metal, and from 9 to 
 14 Ibs. more to force the air through at the proper 
 velocity, or from 15 to 20 Ibs. per square inch total 
 pressure. 
 
 An arrangement for opening and shutting the valve 
 by the rotation of the converter is shown in Fig. 45. 
 The valve, which is of a double-beat form, has its stem 
 prolonged upwards, and carries a weight tending to keep 
 it pressed against its seat. The lifting mechanism con- 
 sists of a lever worked by an eccentric disc attached 
 . to the axis of the converter. When the latter is 
 lowered for filling, the pressure of the eccentric* is 
 taken off the lever, and the valve closes ; but when 
 the motion takes place in the opposite direction, the cam 
 part of the disc lifts the lever, and with it the valve. 
 By this arrangement, the opening and shutting of the 
 valve at the right moment, a point of great importance, 
 are made completely independent of the action of the 
 man working the converter. The form and method of 
 arrangement of the twyer bricks are shown in plan and 
 section in Fig 45, c and D. 
 
 In Sweden and Austria the process is usually con- 
 ducted without remelting the pig iron, which is tapped 
 directly from the blast furnace into the converter. In 
 the former country the addition of spiegeleisen was 
 formerly dispensed with, the blowing being only con- 
 tinued for a very short time after the more rapid 
 
METHODS OF PRODUCING STEEL. 445 
 
 boiling has ceased. The uncertainty of being able to 
 stop the process at the right moment has led to the 
 more general adoption of total decarburisation, and the 
 addition of spiegeleisen in the manner already de- 
 scribed. 
 
 Although spiegeleisen as now made usually contains 
 imicb more manganese, 20 per cent, and above, than 
 that formerly produced from spathic ores, its use has 
 in great part been superseded by the richer alloys, 
 known as ferro-manganese, which contain up to as much 
 as 87 per cent, of the latter metal. They are especially 
 valuable in making extra soft steel where it is desired 
 to add a proportion of manganese without increasing 
 that of carbon, as is done in the production of the so- 
 called phosphorus steel. Another alloy, containing 
 about 10 per cent, of silicon and 20 of manganese (silico 
 ferro-manganese), is specially applied in the production 
 of steel castings, a certain proportion of silicon causing 
 the metal to set in the mould without developing blow- 
 holes. 
 
 It need scarcely be said that the reactions going on 
 in the Bessemer converter are substantially similar to 
 those observed in puddling and hearth fining. The 
 following, one of the earliest complete series of analyses 
 of products taken at different stages of the process that 
 was published, refers to the Austrian Government 
 Works at Neuberg, in Styria. The pig iron operated 
 upon is smelted from the spathic ores of the Erzberg 
 with charcoal, 
 
446 
 
 METALLURGY OF IRON. 
 
 ANALYSES OF METAL. 
 
 i. 
 
 IT. 
 
 in. 
 
 IV. 
 
 v. 
 
 Carbon, graphitic 
 
 3-180 
 
 
 
 
 
 
 
 
 
 ,, combined 
 
 0-750 
 
 2-405 
 
 0940 
 
 0-087 
 
 0-234 
 
 Silicon . 
 
 1-960 
 
 0-443 
 
 0-112 
 
 0-028 
 
 0-033 
 
 Phosphorus . 
 
 0-040 
 
 0-040 
 
 0-045 
 
 0-045 
 
 0'04i 
 
 Sulphur. . 
 
 0-018 
 
 trace 
 
 trace 
 
 trace 
 
 trace 
 
 Manganese 
 
 3-460 
 
 1-645 
 
 0-429 
 
 0-113 
 
 0-139 
 
 Copper . 
 
 0-085 
 
 0-091 
 
 0-095 
 
 0-120 
 
 0-1C5 
 
 i 
 
 
 
 
 
 
 N 0. I. Original pig iron. 
 II. Metal taken at end of first stage. 
 III. after the boil. 
 ,, IV. end of the blowing. 
 V. restored to steel by addition of pig iron. 
 
 COMPOSITION OF SLAGS. 
 
 ii. 
 
 in. 
 
 IV. 
 
 V. 
 
 Silica 
 
 46-78 
 
 51-75 
 
 46-75 
 
 47-27 
 
 Alumina .... 
 
 4-65 
 
 2-98 
 
 2-80 
 
 3-45 
 
 Protoxide of iron 
 
 6 78 
 
 5-50 
 
 16-86 
 
 15-43 
 
 manganese 
 
 37-00 
 
 37-90 
 
 32-23 
 
 31-89 
 
 
 2-98 
 
 1-76 
 
 1-19 
 
 1-23 
 
 Magnesia .... 
 
 1-53 
 
 0-45 
 
 0-52 
 
 0-61 
 
 Potash \ 
 Soda ) ' 
 
 traces throughout 
 
 Sulphur .... 
 
 0-04 
 
 trace 
 
 trace 
 
 trace 
 
 Phosphorus .... 
 
 0-03 
 
 0-02 
 
 o-oi 
 
 0-01 
 
 These analyses are numbered to correspond with those of the metal 
 taken at the same time. 
 
 It will be seen from the above analyses that the iron 
 is not oxidised by the blast to any great extent until 
 nearly the whole of the manganese and carbon have 
 been removed. The retention of the entire quantity 
 of phosphorus contained in the original pig iron in 
 the finished steel is in accordance with observations 
 made in other countries. Newer methods of con- 
 ducting the process, whereby steel of good quality 
 can be produced from Cleveland and similar brands of 
 pig metal rich in phosphorus, are described on page 401. 
 
METHODS OF PRODUCING STEEL. 
 
 447 
 
 In Sweden and Austria the finished steel is classified 
 by numbers, according to the hardness and percentage 
 of carbon, commencing with the most highly carbu- 
 rised. The amount of carbon is determined by Eggertz's 
 colorimetric method, described at p. 489. The following 
 is the proportion of carbon in Bessemer steel from 
 Heft, in Curinthia : 
 
 No. 
 
 Specific gravity. 
 
 Carbon. 
 
 Silicon. 
 
 II. 
 
 7-791 
 
 1-35 
 
 0-02 
 
 III. 
 
 7-828 
 
 1-15 
 
 trace 
 
 IV. 
 
 7-848 
 
 0-85 
 
 0-02 
 
 V. 
 
 7-856 
 
 0-72 
 
 0-03 
 
 VI. 
 
 7-836 
 
 0-53 
 
 traco 
 
 VII. 
 
 7-872 
 
 0-11 
 
 trace 
 
 In Sweden a similar basis of classification is adopted ; 
 but instead of arbitrary numbers, the qualities are dis- 
 tinguished by the actual percentages of carbon. 
 
 At Seraing, in Belgium, the following scale is used. 
 It applies only to the milder qualities. 
 
 
 
 Tensile 
 
 
 
 Class. 
 
 Carbon 
 per cent. 
 
 strength. 
 Kilog. per 
 
 Elongation. 
 per cent. 
 
 Properties. 
 
 
 
 sq. m.m. 
 
 
 
 Extra soft 
 
 0-25 0-35 
 
 4856 
 
 20 to 25 
 
 Welds, but does 
 
 
 
 
 
 not harden. 
 
 Sofb . . 
 Semi -hard 
 
 0-35 0-45 
 0-4o0-55 
 
 j 5669 
 
 10 to 20 [ 
 
 ~Welds,an<l hard- 
 ens imperl't ctly. 
 
 Hard . ., 
 
 0-5.30 -65 
 
 69105 
 
 5 to 10 
 
 Hardens, but does 
 
 
 
 
 
 not weld. 
 
 Inots with more than 
 
 per cent, are classed as 
 
 extra hard, but they are not produced in the regular 
 system of working, 
 
 The slags of the Bessemer process vary considerably 
 in composition from those of the puddling furnace, 
 being much more acid and approximate to the pyroxene 
 formula RO SiO 2 . At Horde, in Westphalia, a crys- 
 
METALLURGY OF IRON. 
 
 tallised slag has been obtained which yielded by 
 analysis 
 
 Silica . - V; '.' : -^ ' ; : ^ :>J . 44-73 
 
 Protoxide of iron V ! . : ; . 20'59 
 
 manganese . : . 82-74 
 
 Lime -. : V rx/-t j .. <- v -.\ 1-53 
 
 Magnesia . . . . . 017 
 
 99-76 
 
 Oxygen, ratio of silica : bases = 23'85 : 12'43. 
 Specific gravity, 3 -08. 
 
 The crystals were found to be of the regular augite 
 form, the angles being intermediate between those of 
 the natural minerals Pajsbergite and Babingtonite, as is 
 also their composition. 
 
 The enormously high temperature developed by the 
 action of cold air on molten cast iron in the Bessemer 
 process is obviously due to the extreme rapidity with 
 which the operation takes place, and the advantageous 
 form of the converter for concentrating the heat 
 developed. For, although the reactions, and con- 
 sequently the heat produced, are in no way different 
 from those of other finery processes, whether in the 
 open fire or reverberatory furnace carbon, silicon, 
 manganese, and some iron being burnt in either case, 
 with the productions of carbonic oxide, silicates of pro- 
 toxide of iron and manganese, and malleable iron we 
 have, in the blowing of a charge weighing five tons, an 
 amount of work done in about twenty minutes that 
 would require from two and a half to three days in its 
 performance in the puddling furnace. It has been 
 pointed out by Jordan that the principal part of the 
 heat developed in the process is due to the combustion 
 of silicon, which, when oxidised to silicic acid, combines 
 with protoxide of iron and other bases, and remains io 
 
METHODS OF PRODUCING STEEL. 449 
 
 (.ho batli in the form of slag ; while in the case of 
 carbon a considerable portion of the heat is expended 
 in volatilising the carbonic oxide produced, which 
 escapes at the temperature of the melted metal, and 
 burns to waste at the mouth of the converter. If the 
 calorific power of silicon be assumed to be the same as 
 that of carbon, the amount of heat produced by the 
 combustion of one kilogramme of silicon to silicic acid 
 will be 8,000 units* when burnt in pure oxygen, or 
 6,382 in air ; the difference between the two quanti- 
 ties corresponding to the amount required to heat up 
 the inert nitrogen. Under the latter condition, one 
 kilogramme of carbon will produce only 475 effective 
 units, being the difference between 2,473 units theoreti- 
 cally developed, and 1,998 units carried off by the 
 gaseous products, carbonic oxide and nitrogen, sup- 
 posing them to escape at a temperature of 1,400?. The 
 use of steam instead of air as an oxidising agent, is, in 
 the case of the combustion of iron or carbon, always 
 disadvantageous, on account of the great amount of 
 heat required to free the oxygen from its combination 
 with hydrogen, which is not reproduced to the same 
 extent in the subsequent formation of carbonic oxide 
 or protoxide of iron. With silicon, however, the con- 
 ditions are somewhat different, as there is a small 
 sensible gain. This will explain the reason why the 
 use of steam in the refinery is only recommended for a 
 few minutes at the commencement of the operation 
 that is, as long as free silicon remains in the pig iron 
 under treatment. 
 
 * This is in excess of the real amount, which has recently heen 
 determined to be 7830. Jordan's original figures are however pre- 
 served, as the quantities are only given as approximations for the 
 purpose of illustrating the theory of the process and not as absolute 
 numerical determinations. 
 
450 METALLURGY OF IRON. 
 
 By applying the quantities given above to the calcu- 
 lation of the amount of heat developed in the blowing 
 of one ton of Bessemer pig iron of the ordinary quality 
 produced in the South of France, which is the following 
 composition per ton of 1,000 kilog. 
 
 Carbon . . f _ . , i; ,.. $fa 42-50 
 Silicon .;; v f) ,.- v ,.. y ; ; ... 20-00 
 Iron and manganese , ;, . 937'50 
 
 1000-00 
 Jordan arrives at the following results : 
 
 Kilogr. Units of heat. 
 
 The combustion of 20 of silicon produces 127,648. 
 
 ,, 42-5 of carbon produces 20,176. 
 
 87*5 of iron and mang. produces 66,237. 
 
 Or a total of . .. . 214,061. 
 
 If we take the specific heat of molten malleable iron 
 at 0*16, the amount of heat developed will be sufficient 
 to raise the temperature of the metal, which is supposed 
 to be completely decarburised, about 1,350 degrees abovo 
 that of the cast iron when run into the converter. 
 
 The great heating power of silicon is therefore to be 
 regarded as the reason for the use of dark grey iron in the 
 Bessemer process ; under ordinary circumstances, about 
 2 CT 2'0 per cent, silicon being considered as essential. 
 Jordan states that in the steel works in the South of 
 France the process could only be carried out by running 
 the cast iron directly from the blast furnace into the 
 converter, the amount of silicon being not sufficient to 
 allow of remelting of the pigs an operation which is 
 usually attended with a loss of about 1 per cent, of 
 silicon. The place of silicon as a heat-producer in tho 
 Bessemer process may be, to some extent, taken by 
 
METHODS OF PRODUCING STEEL. 451 
 
 manganese, as is the case in Styria, where the cast iron 
 used is smelted from the spathic ores. It is, however, 
 less advantageous, because the deficiency in silica, which 
 is required to flux the protoxide of manganese formed, 
 can only be supplied by the destruction of the siliceous 
 lining of the converter. The corrosive action of manga- 
 nese on the hearths of blast furnaces where spathic ores 
 are smelted has already been noticed at p. 224. 
 
 Although silicon is an essential component of good 
 Bessemer pig iron, it is of importance that the amount 
 per cent, should be somewhere about the same as, or not 
 very much more than, that of the carbon. An excess of the 
 former element works prejudicially in two ways first, 
 it gives rise to an increased waste of iron in the slag ; 
 and, secondly, it cannot be completely removed before 
 the whole of the carbon is burnt away, so that it may 
 happen, in the blowing of such metal, that, although the 
 process is apparently complete as determined by the 
 usual indication of the cessation of the flame from the 
 converter, sufficient silicon is retained in the decar- 
 burised metal to render the finished steel brittle and 
 useless. Snelus gives tho following analyses in illus- 
 tration of this point : 
 
 i. n. in. iv. 
 
 Carbon . 0-445 0"515 0-550 0-490 
 
 Silicon . 
 Sulphur . 
 Phosphorus 
 Mangjineso 
 Copper . 
 
 0-814- 0-270 0-6iO 0-009 
 
 0-067 0-033 
 
 0-038 0-036 
 
 0-554 0-- r -76 
 0-031 0-025 
 
 Analyses I., II., and III., are examples of under- 
 blown and brittle steel, rich in silicon ; IV. is tho 
 ordinary composition of good Bessemer rail-steel made 
 at Dowlais. 
 
 The following series of analyses, by the same chemist, 
 
452 
 
 METALLURGY OF IRON. 
 
 of metal taken at different stages of the blow, show 
 very distinctly the gradual removal of the carbon along 
 with the silicon : 
 
 
 I. 
 
 IL 
 
 m. 
 
 IV. 
 
 V. 
 
 VI. 
 
 Carbon, graphitic . 
 
 2-070 
 
 
 
 
 
 
 
 
 
 combined . 
 
 1-200 
 
 2-170 
 
 1-550 
 
 0-097 
 
 0-566 
 
 0-519 
 
 Silicon . 
 
 1-952 
 
 0-795 
 
 0-635 
 
 0-020 
 
 0-030 
 
 0-030 
 
 Sulphur 
 
 0-014 
 
 trace 
 
 trace 
 
 trace 
 
 trace 
 
 trace 
 
 Phosphorus . . 
 
 0-048 
 
 0-051 
 
 0-064 
 
 0-067 
 
 0-055 
 
 0-053 
 
 Manganese . 
 
 0-086 
 
 trace 
 
 trace 
 
 trace 
 
 0-309 
 
 0-309 
 
 Copper . 
 
 
 
 
 
 
 
 
 
 0-039 
 
 0-039 
 
 Ratio of carbon to \ 
 silicon 
 
 [ 1-6: 1 
 
 2-7: 1 
 
 2-4 : 1 
 
 4-8 : 1 
 
 19: 1 
 
 17 : 1 
 
 I. melted charge of pig ; II. metal at end of first stage, 6 minutes 
 from start; III. metal after blowing 9 minutes; IV. over-blown 
 metal, 13 minutes from start, before adding spiegeleisen ; Y. steel 
 from ingot ; VI. steel tfom finished rail. 
 
 It will be noticed on comparing these analyses with 
 the similar series from Styria given on p. 414, that the 
 observed phenomena are substantially the same in both 
 instances. The difference in the amount of copper, 
 which is much larger in the Styrian steel than in that 
 from Dowlais, is to be attributed to the fact that the pig 
 iron used in the former is entirely smelted from spathic 
 ore, while in the latter only the spiegeleisen is due to 
 that source. Copper pyrites, in small quantity, is almost 
 invariably present in spathic carbonates, and however 
 carefully they may be roasted and weathered, some 
 copper, as a general rule, is reduced, and passes into the 
 iron in the blast furnace. 
 
 The progress of the conversion of the charge can be 
 controlled to some extent by observing the spectrum 
 given by the flame with the spectroscope ; and more 
 particularly the moment of complete decarburisation 
 may be determined with considerable accuracy, espe- 
 cially if the flame be bright and free from smoke. The 
 spectrum produced when the combustion is most active 
 
METHODS OP PRODUCING SI EEL, 4*53 
 
 is characterised by groups of numerous lines in the 
 yellow and green portions, that of sodium being the 
 most prominent arid the first to appear among the 
 former. There is also a well-defined group of lines in 
 the blue field, and under the most favourable conditions 
 the violet and red lines of potassium and lithium, 
 together with an extra violet line accompanying the 
 former, are seen. For this, however, an instrument of 
 great defining power, and an extremely bright flame 
 are essential. When the metal is completely decar- 
 burised, the yellow and green lines disappear, but the 
 sodium is persistent, sometimes even after the tipping 
 of the converter. On the addition of the spiegeleisen, 
 the whole of the lines reappear with great brilliancy. 
 When there is much manganese in the cast iron 
 employed, as is the case in Styria, the use of the spectro- 
 scope is difficult, owing to the brown smoky character 
 of the flame. 
 
 At Seraing, it has been found that the disappearance 
 of the dark absorption-bands, which alternate with the 
 bright lines, can be more readily determined than the 
 latter, which often reappear after their apparent extinc- 
 tion, and is therefore to be preferred as admitting of 
 much closer and easier observation. 
 
 The exact chemical character of the spectrum of the 
 Bessemer flame has not as yet been made out, although 
 it has been the cause of considerable controversy, there 
 being two different opinions as to its origin. One of 
 these supposes the lines to be due to carbonic oxide 
 and their cessation to the complete combustion of the 
 carbon, while the other considers that they are mainly 
 produced by manganese, and that their sudden dis- 
 appearance may be accounted for by the diminution in 
 the amount of the metal volatilised until the quantity 
 present in the flame is reduced below that necessary to 
 
454 METALLURGY OF IRON. 
 
 produce them, it having being found that for the detec- 
 tion of manganese by the spectroscope much larger 
 quantities must be employed than are sufficient to pro- 
 duce the ordinary reaction with soda on platinum foil 
 before the blow-pipe. 
 
 Another indication of the progress of the operation, is 
 that afforded by the character of the slag. This has 
 been employed in Austria and Sweden. An iron rod is 
 inserted into the converter, and when. brought out a 
 portion of the slag adheres to the point. So long as 
 any carbon remains unconsumed a peculiar brownish 
 tint is observed, but as soon as the point of total decar- 
 burisation is reached, the slag assumes a dead black 
 colour, with a peculiar metallic lustre characteristic of 
 the presence of protoxide of iron in considerable 
 quantity. This test is said to be capable of great pre- 
 Dision in the hands of experienced workmen. 
 
 At Seraing the following relations have been ob- 
 served between the colour of the converter slag and 
 the temper or proportion of carbon in the blown metal. 
 
 Lemon 3*ellow . , . 0'75 per cent, and above. 
 
 Orange : T . 0-60 ,, 
 
 Light brown . .. 0-45 
 
 Dark brown . . 0'30 
 
 Bluish black . . 0-15 
 
 In the earlier period of the working of the process 
 at Sheffield, the yield of ingots was 77 J per cent., 
 on the weight of the pig iron charged, 15 per cent, 
 being lost in the converter and 7J per cent, in the re- 
 melting in the reverberatory furnace. With three-ton 
 converters the lining required renewal after blowing 
 250 tons, but the endurance of the twyers was much 
 less, and they required to be replaced after every 
 
METHODS OF PRODUCING STEEL. 455 
 
 third or fourth operation. This was done by knocking 
 out the stumps of the worn twyers and inserting new 
 ones, the joint being made tight by pouring in a semi- 
 fluid paste of ganister, or letting the vessel cool so as to 
 be able to send a man to ram the crevices up with the 
 mixture. With this arrangement the number of blows 
 that could be obtained with a pair of converters was 
 only from six to eight in twenty-four hours, as, although 
 the actual blowing did not require more than fifteen or 
 twenty minutes, much time was consumed in the neces- 
 sary operations of casting, and especially the placing 
 and removal of the ingot moulds. For more rapid 
 work it is necessary, therefore, to save time in the sub- 
 sidiary operations of (a) smelting the pig metal ; 
 (b) repairing or replacing the converter linings, wholly 
 or in part; and (c) handling, i.e. placing, filling, and 
 removing the ingot moulds. The first of these 
 requirements is met by the provision of a large num- 
 ber of cupola melting furnaces, or by taking the metal 
 directly in the melted state from the blast furnaces. 
 The former method is practised in America, the latter 
 being confined to European works, where it is be- 
 coming general when the conditions are favourable 
 to its use. Where the works are small, as in Sweden, 
 the converters may be placed close to the pig beds 
 and below them, so that the molten iron may 
 have the smallest possible distance to travel ; but in 
 England, where the steel works are necessarily at a 
 distance from the blast furnaces, the metal is lifted 
 into a ladle mounted upon wheels, which is drawn to 
 the converter by a locomotive, and is either delivered 
 at such a height that it may be tapped directly into the 
 converter, or is lifted by a hydraulic lift. The railway 
 for the ladle usually runs the whole length of the range 
 
456 METALLURGY OF IRON. 
 
 of the blast furnaces in a tunnel below the level of the 
 ordinary pig beds, and the charge is drawn from two 
 or more blast furnaces to obtain uniformity in the 
 quality of the metal. At Barrow the melted metal is 
 taken by a line, which is nearly two miles in length, 
 between the blast furnace and the steel works, but it is 
 not appreciably chillecLby the journey. At Givors, in 
 the South of France, by a combination of this kind 
 a very great economy in fuel has been attained ; with two 
 blast furnaces and two converters about 24,000 tons of 
 steel ingots are produced annually without any further 
 expenditure of fuel than the coke consumed in the blast 
 furnaces. The metal is run directly into the converters, 
 and the waste gas of the furnace tops is sufficient to 
 drive the smelting and Bessemer blast engines and the 
 hydraulic cranes connected with the converters, as well 
 as to heat the blast by the use of Cowper's stoves. 
 
 For facilitating the repair of the twyers, which are 
 subjected to rapid corrosion by the action of the slag, 
 it is now customary to attach the bottom to the body of 
 the converter by eye-bolts and cotters, so that it can 
 be easily detached and replaced when necessary. Par- 
 ticular attention is paid to this point in America, where 
 a special hydraulic lift is placed below the converter 
 for the purpose of facilitating this operation. In the 
 new process of Thomas and Gilchrist, described on 
 page 461, the lining of the converter body, being very 
 rapidly acted upon, requires more frequent replacing 
 than in the older method, and therefore it is necessary 
 to arrange for the substitution of new converters for 
 worn ones without stopping to cool down. This may 
 be done by making the body detachable from the 
 trunnion belt, so that when the converter is reversed 
 it may be dropped upon a lift and lowered to a railway 
 
METHODS OF PRODUCING STEEL. 457 
 
 truck, the new one in the same way being lifted into 
 its place, mouth downwards, when it is keyed up and 
 turned over into the working position. This is the 
 plan devised by the late A. L. Holley, in America. 
 At Eston, the more direct method of lifting the entire 
 converter out of the trunnion bearings by a steam 
 crane travelling on an overhead railway has been 
 adopted. 
 
 The third requirement, that of increased facility in 
 handling the ingots, has been obtained by modifying 
 the arrangement of the different parts of the plant, and 
 more particularly in the position of the converters with 
 reference to the ingot moulds. In the original arrange- 
 ment, where the two converters were placed with their 
 mouths turned towards each other, at opposite ends of 
 the diameter of the circle swept by the centre crane, 
 the space for the moulds was restricted to a semicircle 
 or less ; while by placing them side by side, with their 
 axes parallel, or but slightly converging, a much larger 
 space, up to three-quarters or more of the entire circle, 
 is rendered available for placing moulds, and the 
 number of ingot cranes may be increased. This 
 arrangement was first adopted in America, where it is 
 combined with the further improvement of restricting 
 the central ladle crane entirely to the service of the 
 converters, the ladle, when the melted steel is poured, 
 being transferred to a second crane, commanding a pit 
 of larger radius containing the moulds. The transfer 
 is made by bringing the arms of the two cranes into 
 the same line, and moving the ladle, which is mounted 
 on wheels, by hand gearing or by a hydraulic piston 
 mounted on the frame of the larger crane. It is also 
 found more convenient to work with the moulds at the 
 natural level of the ground, so that in new works the 
 
 x 
 
458 METALLURGY OF IRON. 
 
 sunk pits are no longer used, the converters being 
 mounted on piers or cast-iron standards. 
 L Figs. 46A and 46fi represent a new form of converter of 
 10- tons capacity, mounted in this way, which has been 
 constructed by Messrs. Tannett, Walker, and Co., for the 
 Cleveland steel works. It differs from the older form 
 in having a straight neck, so that it may be charged 
 or poured from either side an arrangement which 
 
 II 
 
 j. 46A. Walker's 10-ton converter. 
 Transverse section. 
 
 allows the wear of the lining to be equalised. The 
 weight is about 40 tons ; the wrought-iron shell-plates 
 are an inch thick, with inch rivets and strong straps ; it 
 divides into four parts, connected by pins and cotters. 
 The belt and trunnions are in two pieces, formed of 
 cast-iron box sections ; the trunnions are 21 inches in 
 diameter and 15 inches long ; the belt weighs 11 tons, 
 
METHODS OF PRODUCING STEEL. 
 
 459 
 
 and is 10 feet 8 inches internal diameter. The tipping 
 gear consists of a worm wheel 8 feet in diameter, 
 gearing into a screw of 4 J inches pitch, which receives 
 motion directly from the cranks of a pair of hydraulic 
 engines mounted on one of the converter standards. 
 This allows the converter to be turned over and 
 over and reversed in either direction. Converters 
 of this form have since been made of larger size, 
 taking 15 -ton charges. 
 They are 24 feet 5 inches 
 high, about one - half 
 taller than Fig. 46; 10 
 feet 8 inches internal dia- 
 meter, and are mounted 
 on piers 20 feet above the 
 ground. 
 
 The following are the 
 principal working results 
 obtained in two English 
 and two American works, 
 in 1880 : 
 
 Doivlais, 8. Wales. Two 
 converters, 10-ton charges 
 pig iron, with 1-2 per cent, 
 manganese and 8 per cent, 
 of spiegel, with 15 per 
 cent, manganese. 13 twyer 
 bricks, with 13 air channels of f inch, giving a twyer 
 area of 487 square inches per ton of metal blown. 
 Blast pressure 15 to 25 Ibs. per square inch. The 
 bottoms last 12 blows without any intermediate re- 
 placing of twyer s. Length of blow 18 minutes. Num- 
 ber of casts per day 28. Make of ingots per week 
 1,600 tons. Yield 88 per cent. 
 
 x2 
 
 Fig. 46s. Walker's 10-ton converter. 
 Side elevation. 
 
460 METALLURGY OF IRON. 
 
 Rhymney, 8. Wales. Three converters, 8-ton charges 
 pig iron, 2 per cent, manganese, and 10 per cent, 
 spiegel, with 20 per cent, manganese. 16 twyer bricks, 
 with 13|-inch holes. Twyer area per ton 2'87 square 
 inches. Blast pressure 30 Ibs. The bottoms last from 
 16 to 30 blows, with the consumption of 24 extra 
 twyer bricks. Length of blow 13 to 15 minutes. Num- 
 ber of casts per day 36. Make per week 1,600 to 1,800 
 tons. Yield 85 per cent. 
 
 Bethlehem, Pennsylvania. Two converters, 7- ton 
 charges pig iron, with 1-5 per cent, manganese, 10 per 
 cent, steel scrap, 10 per cent, spiegel, with 15 per cent, 
 manganese. 12 twyer bricks, each with 12 f-inch 
 holes. Twyer area 2*48 square inches per ton. Blast 
 pressure 25 Ibs. per square inch. Bottoms last 8 to 9 
 blows, with 12 extra twyer bricks per week. Length of 
 blow 15 to 16 minutes. Number of casts 45 to 46 per 
 day. Make per week 1,800 to 2,000 tons. Yield 
 90 per cent. 
 
 Cambria, Pennsylvania. Two converters, 7-ton 
 charges pig iron, with 1-5 per cent, manganese, 18 to 
 20 per cent, steel scrap, 7 per cent, spiegel, with 15 per 
 cent, manganese. 11 twyers, with 12 i-e-inch holes. 
 Twyer area 3-19 square inches per ton. Blast pressure 
 28 Ibs. Bottoms last from 10 to 19 blows. Time of 
 blow 17 minutes. Number of casts 72 per day. Make 
 per week 2,600 tons. Yield 90 per cent. 
 
 The average production of each of the 24 converters 
 at work in America, in the month of November, 1881, 
 was 5,400 tons. The Edgar Thompson and Bethlehem 
 works, Pittsburg, each with a pair of 8 -ton con- 
 verters made in the year 1881, 16,235 tons and 
 16,729 tons respectively. At the former works 
 496 casts were made in the week ending December 
 
METHODS OF PRODUCING STEEL. 461 
 
 3rd, 1881, giving 3,813 tons of ingots, the largest 
 make in twenty-four hours being 700 tons. It is 
 not, however, considered by European steel-makers 
 that these very high working results could be imitated 
 with advantage on economic grounds. 
 
 Basic-Bessemer Process. The method of conduct- 
 ing the Bessemer process described above, and requiring 
 for its success a rich pure pig metal essentially free 
 from phosphorus and sulphur, but containing a notable 
 proportion of silicon, was, with certain modifications in 
 detail, alone practised up to within two or three years 
 of the present time. As the proportion of such pig 
 metal available is comparatively small as compared 
 with the inferior ores of more highly phosphuretted 
 kinds smelted from the newer sedimentary forma- 
 tions in Cleveland, Luxemburg, and elsewhere in 
 Europe, the discovery of means of utilising the 
 latter for steel-making has long been sought by differ- 
 ent investigators. In 1872 Snelus determined by 
 experiment that the retention of phosphorus by the 
 metal was intimately related to the character of the 
 slag (which, as has already been shown, is essentially 
 a normal silicate of the form ROSiO 2 ), and that when 
 this could be rendered of a more basic character the 
 greater part of the phosphorus could be eliminated in 
 the slag in the same way as in the puddling furnace. 
 This he did by the addition of lime and oxide of iron, 
 and more particularly by substituting for the ordinary 
 siliceous converter lining of gAnister, one in which lime 
 and magnesia were the essential constituents, the best 
 results being obtained with bricks made of magnesian 
 limestone which had been burnt at a very high tempeia- 
 ture. These experiments, made upon Cleveland pig 
 iron with 1 to 2 per cent, of phosphorus, showed 
 
462 METALLURGY OF IRON. 
 
 that steel could be made from it with only O'l, or not 
 sensibly more than in that made from hematite. But 
 they were unpublished until the announcement of 
 similar results having been obtained by Thomas and 
 Gilchrist, at Blaenafon, and subsequently as a working 
 experiment at Eston, in Cleveland, where it has since 
 been carried out on the largest scale in regular practice, 
 as well as at Horde and Ruhrort, in Westphalia, and 
 several other works in Germany and Eastern France. 
 The process is now conducted in the following manner : 
 The converter, which is lined either with bricks made 
 of hard burnt dolomite set in tar asphalte, or with the 
 same rendered plastic and rammed round a core, is 
 heated by a fire of coke breeze, and a quantity of quick 
 lime equal to 15 or 20 per cent, of the weight of the 
 charge of metal is thrown in. The latter may contain 
 any amount of phosphorus, but should be as free as 
 possible from silicon and sulphur, the latter being cor- 
 rected by a proportion of manganese when white iron 
 is used. It should be poured in as hot as possible. 
 The blowing is conducted in the ordinary way until the 
 whole of the carbon is burnt off, which requires about 
 ten minutes, when, instead of casting, the blast is kept 
 on for two or three minutes longer, which causes a great 
 increase in the temperature of the bath with a thicken- 
 ing of the converter smoke. This so-called afterbloiv 
 is the period of dephosphorisation ; its duration is con- 
 trolled by taking a test of the metal in a ladle, which 
 is cast and flattened under a steam hammer, cooled 
 in water, and broken, which can be done in five minutes. 
 When the desired malleability is obtained the converter 
 is tipped to run out the slag, and spiegeleisen or ferro- 
 manganese is added in the usual way. The removal of 
 the slag is important, as a portion of the phosphorus 
 
METHODS OF PRODUCING STEEL. 463 
 
 may be reabsorbed if it is left in contact with the 
 melted metal. 
 
 At Eston the converter linings are made of dolomite 
 carefully ground and burnt, mixed with tar which has 
 been well boiled to deprive it completely of water. The 
 upper part is removable, and is lined separately ; the 
 body is, however, relined in place by inserting a 
 tapered cast-iron plug heated by a coke fire, and corre- 
 sponding in size to the inside dimensions of the new 
 lining. The space between this and the old lining, 
 which is not allowed to wear thinner than 3 or 4 
 inches, is filled with the mixture of tar and dolomite, 
 which becomes plastic when heated. When the blow 
 is finished both metal and slag are poured into the 
 ladle, and a proportion of hematite pig, rich in silicon, 
 equal to 4J per cent, of the charge, is run in through a 
 spout. This causes a very violent reaction, the bulk of 
 the slag being blown out and run into a proper 
 receptacle. The spiegel is then added and the metal 
 is cast. The bottoms are made by ramming a mixture 
 containing less tar than that used for the body lining 
 around a series of |-inch core pins which occupy the 
 place of the twyer bricks. They last eleven blows, as com- 
 pared with eight when made of ganister. Nearly 1,000 
 tons of steel can be made without relining the body. 
 
 According to Thomas's summary of the general 
 results obtained, the production of steel for lining 
 is considerably less than in the original pro- 
 cess, and therefore for a given make the number of con- 
 verters or the facilities for changing them should be 
 increased, but no increase of engine-boiler or crane 
 power is necessary. 
 
 With three converters from 22 to 24 charges are 
 blown per day in Germany. The linings require con- 
 
464 METALLURGY OF IRON. 
 
 siderable repairs after a number of charges varying 
 from 40 to 70 (average 56) have been blown ; the bot- 
 toms may last from 8| to 21 blows (average 14). The 
 average consumption of basic material in lining is 
 rather under 1 cwt. per ton of steel, and for preparing 
 it 24 cwt. of coal or 16 cwt. of coke is required. The 
 consumption of lime for slag making is about 3 cwt. 
 per ton of steel. This slag contains about 50 per 
 cent, of lime, iron 10 per cent., phosphoric acid 12 per 
 cent., silica 15 per cent, in maximum, and variable 
 quantities of manganese according to the source of the 
 metal. It is now returned to the blast furnace as flux. 
 The loss upon the weight of the pig charged varies 
 from 13 to 19 per cent., averaging 15 per cent, as com- 
 pared with 12 when working hematite iron. The dura- 
 tion of the operation, including afterblow, varies from 
 thirteen to twenty-five minutes, not including time for 
 sampling, which when practised takes from three to four 
 minutes more. White pig iron is now generally preferred, 
 but white, grey, or mottled metal may be used indif- 
 ferently. The amount of phosphorus in eleven varieties 
 actually treated varied from 1 to 3 per cent.,* that of sili- 
 con from 0'5 to 1*3 per cent., and of manganese from 
 0*35 to 2*0 per cent. Where the silicon exceeds about 
 1 per cent, the metal may be best treated by blowing 
 it first in an ordinary ganister-lined converter for a few 
 minutes, and then transferring it to the basic-lined one, 
 whereby the wear of the latter is sensibly diminished. 
 
 The progressive transformation of the metal during 
 the operation has been studied by several chemists. 
 The following is an example given by Jordan of the 
 
 * Phosphorus, as a source of heat, takes the place of silicon in the 
 ordinary process ; the unit of phosphorus, burning to PgOs, evolves 
 5,867 heat units. 
 
METHODS OF PRODUCING STEEL, 
 
 465 
 
 blowing of a charge at the Rhenish steel works in 
 Westphalia : 
 
 
 A 
 
 B 
 
 C 
 
 D 
 
 Carbon 
 
 3-276 
 
 0-590 
 
 0-026 
 
 0-302 
 
 Silicon . 
 
 0-476 
 
 0-022 
 
 0-002 
 
 0-016 
 
 Manganese 
 
 1-131 
 
 0-122 
 
 0-197 
 
 0-540 
 
 Phosphorus 
 
 2-600 
 
 2-064 
 
 0-062 
 
 0-092 
 
 Sulphur 
 
 0-062 
 
 0-139 
 
 0-051 
 
 0-040 
 
 A. Original metal melted from cupola. 
 
 B. After blowing ten minutes, the silicon is 
 almost entirely, and the carbon nearly, removed, while 
 the phosphorus is almost unchanged. The ordinary 
 blow lasted 13J minutes, when the carbon had dimi- 
 nished to 0-124 per cent. 
 
 C. After two minutes' overblow, the phosphorus is 
 rapidly oxidised together with the iron, the carbon 
 and silicon not being further changed. 
 
 D. After addition of spiegeleisen. This augments 
 the carbon and silicon, and, to a slight extent, manga- 
 nese and phosphorus the latter by the reducing action 
 of the carbon of the metal upon the phosphoric acid 
 of the slag. In this case the proportion of sulphur re- 
 tained is rather high ; usually about one-half is elimi- 
 nated. 
 
 The final slags were of the following composition : 
 
 Silica 
 
 Phosphoric Acid (P 2 5 ) 
 
 Iron, Protoxide . 
 
 Lime 
 
 Magnesia 
 
 Sulphur 
 
 E 
 8-05 
 
 18-55 
 8-37 
 4-45 
 
 56-54 
 3-10 
 0-33 
 
 F 
 
 8-22 
 
 17-15 
 
 9-24 
 
 6-27 
 
 56-03 
 
 3-29 
 
 0-29 
 
 x3 
 
466 METALLURGY OF IRON. 
 
 E. At the end of the blow. F. After the addition 
 of the spiegeleisen. 
 
 Open-hearth Processes. The production of cast 
 steel by dissolving malleable scrap in molten cast iron 
 without the use of crucibles was patented by Heath in 
 1845, and a similar method in 1855 by Price and 
 Nicholson. The first actual fusion of cast steel in the 
 bed of a reverberatory furnace was effected by Sudre, 
 in France, in 1860 when quantities of tool steel up to 
 two tons at a time were run into ingots from a furnace 
 analogous to that used in iron melting, the heat being 
 intensified by a forced draught under the grate, with 
 the result of rapidly destroying the furnace. The 
 introduction of the regenerative furnace, in which the 
 highest temperature can be obtained without strong 
 draught or cutting flame, has, however, furnished the 
 required solution of the problem, and in 1862 it was 
 applied by Attwood, of Towlaw, and Martin, of Sireuil, 
 in France, and subsequently with improvements and 
 modifications in the furnaces and the modes of manipu- 
 lation by Siemens, Pernot, and others. As it was first 
 worked on the large scale by Messrs. Martin, the name 
 Martin-Siemens process is generally used on the 
 Continent ; the modification, using iron ore instead of 
 scrap iron, is known as the Siemens process ; and latterly 
 the general name of open-hearth process has come into 
 use for both. 
 
 An early form of the furnace is represented in longi- 
 tudinal and transverse sections in Fig. 47. The 
 regenerators A A (air) and G G (gas) are placed below 
 the bed in the usual manner. The bed A B is made 
 of quartz sand consolidated by pressure and strong 
 heating, and is supported by a frame of cast-iron 
 plates which is kept cool by a current of air circulating 
 
METHODS OF PRODUCING STEEL. 
 
 467 
 
468 METALLURGY OF IRON. 
 
 in the space between it and the top of the regenera- 
 tor chambers. The bed is hollowed towards the middle 
 and with a slight inclination towards the tap-hole, 
 which is placed below the middle working door on the 
 front side of the furnace. The ladle c, which is simi- 
 lar in general arrangement to that used in the Bessemer 
 process, is mounted on wheels and runs on a railway, 
 the ingot moulds being arranged in a straight line in a 
 pit below A. 
 
 In the newer forms of this furnace the roof is made 
 with a strong slope from the flue ends to the centre, 
 giving a more plunging flame. The ventilating space 
 below the bed is much enlarged. The gas ports for 
 equal area are made longer and narrower, and the 
 regenerators of increased size are roofed with semi- 
 circular instead of segmental arches, in order to give a 
 larger exhaust flue for the flame, and thus to moderate 
 its temperature before it reaches the regenerator. The 
 size and capacity are also greatly increased, the original 
 charges of 35 cwt. to 5 tons having been increased to 
 8, 10, or in some instances 15 tons. 
 
 The materials used are good pig iron from hematite, 
 which need not be as grey as that required in the Bes- 
 semer process for the initial bath, malleable iron in the 
 form of blooms, sponge, or puddle bars, clean scrap, 
 whether of iron or steel, old rails, and iron ore of good 
 quality, as additions, and spiegeleisen and ferro-man- 
 ganese for the final tempering. 
 
 The first operation consists of forming the bath by 
 charging the required quantities of pig iron, to which, 
 when melted, additions of iron or steel are made in 
 small quantities at a time ; they are charged cold on the 
 hinder flame bridge, and when strongly heated are 
 turned into the bath. This is the English practice ; 
 
METHODS OF PRODUCING STEEL. 469 
 
 on the Continent an auxiliary heating furnace is gener- 
 ally used, the scrap being made red-hot before 
 charging. The direction of the draught in the melt- 
 ing furnace is changed every half-hour. The propor- 
 tion of scrap used depends upon its character and the 
 condition of the furnace. With an almost neutral 
 flame, No. 1 grey pig iron will dissolve ten times its 
 weight of Bessemer scrap with 0*3 or 0*4 per cent, of 
 carbon, but No. 3 will not take more than three or 
 four times its weight of soft puddled iron, and 
 when the flame is cutting, a considerably less propor- 
 tion. 
 
 When the charge is melted the metal is tested from 
 time to time by taking samples in a ladle, which, after 
 cooling in water, are hammered and broken. When 
 the required pitch, as indicated by the toughness and 
 fracture, has been attained, from 6 to 9 per cent, 
 of spiegeleisen or ferro-manganese is added, and when 
 this is melted the charge is tapped out into the ladle 
 and cast into ingots, in the same way as in the 
 Bessemer process. The time required for working a 5 to 
 6 ton charge is from nine to eleven hours. The loss in 
 melting Bessemer scrap with No. 3 hematite pig is 
 from 4 to 5 per cent, of the total weight of the charge. 
 The coal used is from 13 to 14 cwt. per ton of steel 
 made. 
 
 In the Siemens' process, with iron ore, the bath of 
 pig iron is decarburised by the addition of rich pure 
 hematite or magnetite, in about 2-inch lumps. This 
 causes a violent boiling, which is kept up until the 
 metal is nearly soft enough, when it is allowed to stand 
 for a short time to allow the iron to clear from 
 the slag, a small quantity of limestone being added 
 at intervals to throw down some of the iron. The 
 
470 METALLURGY OF IKON. 
 
 spiegel is then added, about 1 per cent, more being 
 used than in the scrap process. From 20 to 24 cwt. of 
 ore are used in a 5-ton charge ; about one-half the 
 metal is reduced and passes into the steel, so that the 
 yield in ingots is from 1 to 2 per cent, in excess 
 of the weight of pig metal and spiegeleisen charge. 
 The consumption of coal is rather larger than in the 
 scrap process, or from 14 to 15 cwt. per ton of steel. 
 The two processes are often combined, both scrap and 
 ore being used in the same charge. The latter is 
 obviously of value as a tempering material. 
 
 At Saint Chamond, in France, the Siemens' process 
 is carried on at a very large scale in Pernot's furnace, 
 shown in longitudinal and transverse sections in Figs. 48, 
 49. It has a circular bed on wheels that can be rotated 
 when heated, and is removable for repair. The bed, 
 made of sand upon an iron-plate bottom, is contained 
 in a frame made of cast-iron staves, kept together by a 
 stout iron hoop. It is inclined about six degrees 
 to the horizon, and is supported by a central spindle 
 and conical friction rollers, upon a cast-iron travelling 
 frame, with four or six wheels, running upon a railway. 
 By means of gearing wheels the bed is rotated at from 
 two to four revolutions per minute. The pig iron and 
 scrap are heated to redness before charging, and 
 as the position of the different pieces of the latter 
 is constantly changing, being alternately brought 
 under the full action of the flame and plunged into 
 the liquid, the fusion is very rapid. One-half of the 
 bed being also exposed to the flame by the slipping of 
 the charge at each revolution, the bottom heat is 
 continuously renewed, and the chilling or sticking of 
 the charge on the bottom is prevented. The removable 
 hearth, shown as withdrawn from the furnace in the 
 
METHODS OF PRODUCING STEEL. 
 
 471 
 
 dotted lines in Fig. 48, allows repairs of the roof 
 to be more readily and quickly made than is the case 
 
 Fig. 48. Pernot's steel melting furnace. 
 Longitudinal section. 
 
 with those of fixed construction. The diameter of the 
 
 Fig. 49. Pernot's steel melting furnace. 
 Transverse section. 
 
 hearth within the lining is about 7 feet in the 8-ton, 
 and 13f feet in the 20-ton furnace ; the depth of the 
 
472 METALLURGY OF IRON. 
 
 Steel 
 Waste. 
 Tons. 
 
 Puddled 
 Iron. 
 Tons. 
 
 Ferro- Carbon 
 manganese, in bath. 
 Tons. Per Cent. 
 
 5,000 
 3,000 
 
 
 
 0-5 
 
 3,000 
 
 
 
 0-4 
 
 bath being about 8 or 9 inches in the centre. The 
 former melts from three to four charges, and the latter 
 two, in the twenty-four hours. 
 
 The following represent the progressive steps in the 
 melting of a charge in the 20 -ton furnace : 
 
 Pig iron 
 Hour. 
 
 Tons. 
 
 2.10 a.m. 6,000 
 
 4.45 
 7.0 
 
 9.40 500 2,000 0-2-5 
 
 11.50 1,000 0-25 
 
 1.25p.m. 0,603 0-12 
 
 1.30 Metal tapped out . . f . .,..,. . 0-.5 
 
 The pig iron contained 3*35 per cent., and the 
 ferro-manganese 50 per cent, of manganese. The coal 
 used is about 1-5 cwt. in the heating furnace, and 5 to 
 5-2 in the melting furnace, per ton of ingots, or only 
 about one-half of that of the fixed furnace. The 
 loss upon the weight of the charge is 4 to 5 per 
 cent, on hard, and 6 to 7 per cent, on soft steel. 
 
 In Ponsard's modification of the rotatory hearth- 
 furnace, or " Forno Convertisseur," a wind chest is 
 added to the bottom spindle, and twyers are inserted in 
 the side lining, so that a decarbonising blast may 
 be injected as in the Bessemer process. This has 
 been used experimentally with fair results, but has 
 not been adopted in the large scale. 
 
 The dephosphorising process by means of lime may 
 also be carried on in the open-hearth furnace. Experi- 
 ments have been made in this direction at the Alexan- 
 drowsky works, in Russia. The bed of the furnace is 
 made of a mixture of calcined dolomite and tar, which 
 
METHODS OF PRODUCING STEEL. 473 
 
 burns to a very hard mass. The composition of the 
 charge was as follows : 
 
 Per Cent. 
 
 Iron Ore from Sweden . Fe 48 per cent. 6 -7 
 
 Lime 6'7 
 
 Cleveland Pig Iron . P. 1-62 ,, 25'0 
 
 Broken Ingot Moulds . 0*70 4-5 
 
 Malleable Scrap . . 0'30 44-5 
 
 Hematite Pig .... 6- 7 
 
 Spiegeleisen . . . Mn 15-0 ,, 5*4 
 
 Ferro-manganese . . ,, 75-0 0*5 
 
 100 
 
 About two-thirds of the lime and iron ore were first 
 charged with the pig iron and part of the scrap, the 
 remainder of the former and the latter following at 
 short intervals. When a test-piece of the metal, after 
 cooling in water, can be bent double without breaking, 
 the hematite pig is added, and, after its complete in- 
 corporation and a fresh testing of the metal, the spiegel 
 and ferro-manganese. Before tapping, and before each 
 addition to the charge, care must be taken to remove the 
 highly phosphuretted slag. The proportion of phos- 
 phorus in the original metal equals 0*571 per cent. ; 
 this is reduced to 0*06 in the ingots. 
 
 Fluid Compression of Steel. Large masses of cast 
 steel, whether from the crucible, Bessemer, or open- 
 hearth furnace, are rarely solid throughout ; the tops 
 of large ingots being generally pitted or honeycombed 
 with small holes for some distance down, and the 
 un soundness increases with the softness of the metaL 
 It was formerly supposed that these bubbles were dus 
 to the evolution of carbonic oxide, produced by the 
 reducing action of combined carbon upon oxide of iron 
 
474 METALLURGY OF IRON. 
 
 taken up in the metal in the last stage of the process ; 
 but the researches of Parry, Miiller, and other chem- 
 ists have shown that the gas included in steel is 
 almost entirely hydrogen, which is absorbed in large 
 quantities by the fluid metal and given out on solidifi- 
 cation in the same way as oxygen is absorbed by 
 melted silver. Miiller considers that the beneficial 
 effect of the final addition of spiegeleisen is in part- 
 due to the sudden large evolution of carbonic oxide, 
 which sweeps out much of the dissolved hydrogen. 
 This is borne out by the experiments of Allan, who 
 finds that Bessemer metal gives sounder ingots when 
 it is stirred by a rotating paddle lowered into the 
 ladle before casting, than when poured in the ordinary 
 way. A large amount of gas is given off in stirring, 
 which fires on meeting the air. 
 
 Another method of obtaining sound ingots is that of 
 causing the metal to solidify under pressure. This 
 was first adopted by Sir Joseph Whitworth, who had 
 moulds built up in segments of cast iron with numerous 
 perforations for the escape of gases, and bound to- 
 gether with a strong tube of cast steel. The interior 
 of the mould is lined with sand. When the metal is 
 run in, the piston of a hydraulic press descends upon 
 the upper surface, and a pressure of about 6 tons to 
 the square inch is applied. The ingots are considerably 
 shortened as compared with those cast in open moulds, 
 but it has been questioned whether their soundness is 
 invariably increased. 
 
 A simpler method of consolidation has been applied 
 by Captain Jones, who subjects the top of the liquid 
 metal in a closed mould to steam pressure. A steam 
 drum is fixed to the side of the ingot crane, having 
 a number of cocks corresponding to those of the moulds, 
 
METHODS OF PRODUCING STEEL. 475 
 
 and india-rubber connecting 1 pipes. The moulds and 
 bases are kept together by clamps attached to long iron 
 rods fitting over projecting lugs at the bottoms. At 
 the upper end of the mould a conical seat is turned, 
 which carries the pouring cup. When the mould 
 is filled, the lid, with a coupling and flexible steam pipe, 
 is substituted and wedged down, the conical seat giving 
 a steam-tight joint. The steam, which may be from 
 80 to 150 Ibs. pressure per square inch, is then turned 
 on, and is allowed to act until the metal has set. The 
 highest pressure is required with mild steel. The 
 ingots are perfectly sound, and are 1J to 2 inches 
 shorter than those cast in the ordinary way with sand 
 stopping. 
 
 In a modification of the above method recently 
 patented by Krupp, the pressure of carbonic acid gas 
 is substituted for that of steam. The acid in the liquid 
 state is contained in a bottle communicating with 
 the mould near the top, by a pipe of small bore. The 
 mould, hooped with steel, is connected with the cover 
 by bolts and wedges, an expanding copper ring help- 
 ing to make the joint gas-tight. The feeding hole in 
 the cover is closed by a sliding wedge. "When the 
 metal is poured the surface is covered with a layer of 
 sand, slag, or other bad-conducting material, the feed- 
 ing hole is closed, and the gas tube opened. The 
 pressure exacted depends on the temperature of the 
 fluid acid, which is immersed in a cistern of water, 
 which may be artificially heated or cooled as required. 
 The tension of carbonic acid gas increases very rapidly 
 with the temperature, being 52 atmospheres at 15 
 degrees, 82 at 35 degrees, 400 at 200 degrees, and 800 
 at 200 degrees. 
 
 Manipulation of Steel Ingots. It was formerly cus* 
 
476 METALLURGY OF IRON. 
 
 ternary to subject heavy ingots, whether from the Bes- 
 semer or open hearth process, to the action of a, steam 
 hammer before rolling, but this is now generally given 
 up, at least in the manufacture of rails, for which purpose 
 the bulk of the steel so produced is applied. The in- 
 gots, when withdrawn from the mould, are conveyed 
 while still hot to a reheating furnace, usually of the 
 Siemens, Bicheroux, or some equivalent form, and when 
 at a good orange-red heat are passed through the " cog- 
 ging " mill, corresponding to the blooming mill of the 
 puddling forge, which reduces them from a pyramidal to 
 a parallel-sided form with a corresponding elongation. 
 These are then returned to the furnace, and when re- 
 heated are finished at one operation in the rail mill. 
 As the crop ends and pieces of irregular lengths are 
 more difficult to dispose of than those of malleable iron, 
 it is now customary to use large ingots giving finished 
 bars long enough to cut into several rails with only one 
 pair of crop ends. At Eston ingots of 35 cwt. giving 
 four rail lengths are used. At "Workington ingots 
 giving three rails are passed nine times through the 
 cogging mill, and thirteen times through the rail mill 
 to obtain the finished section. 
 
 In forging heavy ingots for artillery, marine en- 
 gine shafts, &c., steam hammers from 50 to 110 tons 
 falling weight are used ; but they are now being re- 
 placed by hydraulic presses from 3,000 to 5,000 tons 
 squeezing power, which consolidates the interior of 
 the ingot far more perfectly than the hammer. A 
 3,000 ton press is considered to be of equal efficiency 
 to a 100 ton hammer. 
 
 Pointed steel projectiles for piercing armour plates 
 are made at Terre-Noire from open hearth steel, with 
 carbon 0*45 to 0-60, silicon 0*25 to 0-3, and manganese 
 
METHODS OF PRODUCING STEEL. 477 
 
 0-5 to 0-6 per cent., by casting in metal moulds with a 
 contracted sunk head of sand above. They are made 
 solid, and if required as shells are bored out afterwards. 
 In the hardening process the projectile is heated to 
 redness, and the point is dipped into water until the 
 redness has disappeared, when it is transferred to an 
 oil bath and allowed to cool. The weight of the oil 
 in the bath should be at least four times that of the 
 piece immersed. The oil adhering to the hardened 
 piece is removed by a gentle tempering heat. Large 
 objects must be annealed vertically to avoid warping 
 by unequal lateral contraction. 
 
 Combining Steel with Wrought Iron. Compound 
 armour plates for ships are now made by cast- 
 ing melted steel upon a wrought-iron base and rolling 
 the combined mass when sufficiently cooled. For 
 a compound plate of the finished size, 16 feet by 
 6J feet and 8 inches thick, a foundation plate 
 of wrought iron, 9f feet by 6 feet and 12J inches thick, 
 is prepared, and a mild steel plate, 2 inches thick, 
 made from a 50-cwt. ingot of open-hearth steel, con- 
 taining about 0-45 per cent, of carbon, is attached 
 to it by distance pieces and steel screws, leaving a 
 hollow space of 5 inches between the two plates. 
 This when brought to a strong red heat is placed 
 upright in a rectangular moulding box, the steel 
 side being placed close to a thick cast-iron plate, 
 the remaining sides being filled with foundry sand, and 
 the bottom built up with fire-brick. The space between 
 the plates is then filled with melted open- hearth steel 
 poured from a 5-ton ladle at the highest attainable 
 temperature, the metal being run through several feed- 
 holes in a gutter lined with fireclay fixed above the 
 mould, which is sunk in a pit in the usual way. When 
 
478 METALLURGY OF TRON. 
 
 the casting has cooled to a red heat it is lifted by a 
 crane and rolled to the required dimensions at once^ 
 The resistance of these plates to penetration is about 
 20 per cent, greater than that of soft iron plates of 
 equal thickness. The adhesion between the two metals 
 is perfect, a layer of steely iron being formed at the 
 junction, while the outer steel face retains its full 
 temper. The latter is about one-third of the total 
 thickness in the heavier plates, and somewhat more 
 in the lighter ones, or about 3 inches in an 8-inch and 
 4 to 4J inches in a 14-inch compound plate. 
 
 If the plate is to be curved, the soft cover is placed 
 on the convex side. The wrought-iron side-pieces 
 and screws are removed in the process of plaining the 
 plate to the finished dimensions. 
 
 The following are the analyses of the constituents of 
 a good compound plate : 
 
 Steel Face. Iron Foundation. 
 
 Carbon. . . . 0-573 0-040 
 
 Silicon . . . . 0-173 0-117 
 
 Manganese . u<*^ l-a 1 0-617 0-090 
 
 Phosphorus . >j. $0 .1tr. 0-054 0165 
 
 Sulphur . . , 0-046 0-010 
 
 Copper .... 0-026 0-016 
 
 Hardening and Tempering Steel. The property of 
 becoming hardened by sudden cooling irom a high 
 temperature is possessed by all varieties of malleable 
 iron containing more than 0'25 per cent, of carbon. 
 The degree of hardness imparted by the operation is 
 dependent partly on the amount of carbon present, and 
 partly, but in a greater degree, on the difference of 
 temperature between the heated metal and that of the 
 fluid employed in hardening, and the rapidity with 
 
METHODS OF PRODUCING STEEL. 479 
 
 which the cooling takes place. Those fluids that possess 
 the highest conducting power for heat produce the 
 greatest hardening. Thus, mercury is most efficacious 
 in this respect, whereas alcohol is entirely without 
 action. 
 
 The specific gravity of steel is diminished by harden- 
 ing. According to Hausmann, hard unweldable cast 
 steel from Solingen was reduced from 7-844 to 7*760, 
 and a softer welding quality from 7-858 to 7-801, by 
 quenching from a red heat in cold water. The change 
 of volume is not uniform even for objects of a regular 
 form. Caron found, by repeating the operation on the 
 same bar for many times in succession, that hammered 
 bars contracted in length and increased in the other 
 dimensions. With rolled bars and sheets, on the other 
 hand, an increase in length was observed. After thirty 
 hardenings, the specific gravity was diminished from 
 7-817 to 7-743. 
 
 The process of tempering consists in reheating 
 hardened steel to a temperature varying with the de- 
 gree of hardness required, and cooling it by immersion 
 in the same manner. The proper temperature is indi- 
 cated by the colour of the thin film of oxide formed on 
 the surface of the heated steel, according to the follow- 
 ing scale : 
 
 Temperature. Colour. Proper temper for 
 
 220 Pale yellow. Lancets! 
 
 230 Straw yellow. Razors and surgical instruments* 
 
 243 Golden yellow. Common razors and penknives. 
 
 255 Brown. Cold chisels, shears, scissors. 
 
 * ^P^lf} A*e,, planes, & c. 
 
 277 Purple. Table knives, large shears. 
 
 288 Bright blue, Swords, coiled springs. 
 
 293 Full blue. Fine saws, augers, &c* 
 
 316 Dark blue. Hand and pit saws. 
 
480 METALLURGY OF IRON. 
 
 The reheating is generally effected in baths of molten 
 metals, or metallic alloys having definite fusing points. 
 Thus, alloys of tin and lead, in varying proportions, 
 may be used up to a temperature of about 300 ; above 
 which, boiling linseed oil and pure lead are to be 
 employed. 
 
 Steel gun- tubes and projectiles are tempered in oil, 
 whereby their tenacity is considerably increased. 
 
 CHAPTER XIX. 
 
 ANALYSIS OF CAST AND WROUGHT IRON AND STEEL. 
 
 THE chief points required to be determined in the 
 analysis of the different kinds of metallic iron for com- 
 mercial purposes are carbon, distinguishing the graphitic 
 from that in the combined state, silicon, sulphur, phos- 
 phorus, manganese, and copper, while the remaining 
 common heavy metals, and those of the alkaline earths, 
 are of less importance, as occurring only in minute 
 quantities, and requiring the use of refined analytical 
 methods, which involve too great an expenditure of 
 time and materials to be employed except in special 
 inquiries. 
 
 Determination of the Total Amount of Carbon. When 
 iron containing carbon in the state of combination is 
 dissolved in hydrochloric acid, protochloride of iron is 
 formed with the evolution of hydrogen, which in the 
 nascent state combines with a portion of the carbon 
 set free, at the same time forming volatile hydrocarbons, 
 which escape, giving a fetid odour to the gas. If, how- 
 ever, instead of hydrochloric acid, a metallic chloride, 
 reducible by iron, is used, no evolution of hydrogen takes 
 place, and the whole of the carbon goes down in an 
 
ANALYSIS OF CAST AND WROUGHT IRON AND STEEL, 481 
 
 insoluble form, and maybe collected. The uncombined 
 or graphitic carbon is not in any way attacked by the 
 acid. The reagent generally used is protochloride of 
 copper, CuCl 2 , which was first introduced by Berzelius. 
 About 100 grains of the metal in a finely-divided state, 
 usually drill chips, borings, or filings, are treated with 
 a moderately strong solution of protochloride of copper 
 until the whole is decomposed. Protochloride of iron is 
 formed, and metallic copper, which remains undissolved, 
 together with the carbon and silicon. The insoluble 
 residue is collected on a filter, and washed, first with 
 weak hydrochloric acid, then with a solution of potash, 
 and lastly, with water, leaving only the carbon and 
 copper behind, which, when dried, are burnt with 
 oxide of copper in a hard glass tube, according to the 
 ordinary method adopted in organic analysis. As 
 the graphite is difficultly combustible, it is best to 
 burn it off in a current of free oxygen. The total 
 amount of carbon is deduced from the carbonic acid 
 produced in the combustion, which is absorbed by caustic 
 potash in the usual way. In Bichter's modification of 
 the above process a solution of the double chloride 
 of copper and sodium, Nad + CuCl 2 , is employed 
 instead of chloride of copper alone. By properly pro- 
 portioning the amount of the double salt employed, 
 the separation of metallic copper may be prevented, 
 which is retained in solution as subchloride. 
 
 Regnault's method of burning the iron directly with 
 oxide of copper, or chromate of lead, can only be 
 adopted when the substance under examination is sus- 
 ceptible of being reduced to a fine powder, an operation 
 of considerable difficulty with many varieties of iron. 
 Weyl's method, which does not require the sample to 
 be powdered, consists in effecting the solution of the 
 
 T 
 
482 METALLURGY OF IRON. 
 
 iron with hydrochloric acid, aided by a weak galvanic 
 current. A lump of the iron to he treated is partly im- 
 mersed in weak hydrochloric acid in connection with 
 the positive pole of a single Bunsen cell, the negative- 
 pole being formed by a plate of platinum. The dis- 
 tance between the poles must be regulated so that no 
 sesquichloride of iron is formed, a point that may be 
 readily determined by the appearance of a yellow tint 
 in the liquid. As soon as the immersed portion of the 
 iron is dissolved the remainder is removed, washed, 
 dried, and carefully weighed : the difference or loss on 
 the original weight gives the amount of iron dis- 
 solved. The carbon and other insoluble matters are 
 collected on an asbestos filter, and treated in a similar 
 manner to that already described. 
 
 Ullgren's method depends upon the oxidation of the 
 total amount of carbon to carbonic acid without heat 
 by means of chromic acid. The first operation consists 
 in treating the finely- divided iron with sulphate of 
 copper, producing metallic copper and protosulphate of 
 iron, carbon and other insoluble substances being pre- 
 cipitated. The precipitate is washed by decantation, 
 and removed into a flask with the smallest possible 
 quantity of water. Strong sulphuric acid, is then added, 
 and after the liquid has cooled, a certain quantity of 
 chromic acid, which is decomposed by the carbon, pro- 
 ducing carbonic acid, which is collected in a weighed 
 tube containing caustic potash in the usual way. 
 This method was reputed to give good results, but, 
 according to Schnitzler, is not available for the analysis 
 of steel, the results indicated being inferior in accuracy 
 to that of Berzelius, and in some instances as much as 
 30 per cent, too low on the total amount of carbon 
 contained. 
 
ANALYSIS ()!' CAST AND WROUGHT IKON AND STEEL. 483 
 
 A. new method, suggested by Fresenius, of dissolving 
 the iron in hydrochloric acid, and leading the car- 
 buretted hydrogen formed over ignited oxide of copper, 
 BO as to convert it into carbonic acid, is said to give 
 good results with steel and dark grey pig iron contain- 
 ing but little combined carbon. The graphitic portion 
 remaining in the residue is then estimated by a second 
 combustion. Schnitzler gives the following estimation 
 of carbon in the same steel by different methods as a 
 measure of their relative accuracy : 
 
 
 I. 
 
 n. 
 
 III. 
 
 IV. 
 
 V. 
 
 VI. 
 
 VII. 
 
 Combined carbon, per cent. 
 Graphitic 
 
 Tctal carbon . 
 
 
 
 
 
 0-68 
 
 
 
 0-96 
 
 0-19 
 0-78 
 
 0-18 
 0-74 
 
 0-92 
 
 074 
 
 075 
 
 0-93 
 
 0-92 
 
 Nos. I., II., III. Determinations by "Weyl's method. Nos. IV., V. 
 By Berzelius's method with chloride of copper. Nos. VI., VII. By 
 Fresenius' s method of determining' the combined carbon directly. The 
 latter is not applicable to such irons as contain a large amount 
 of combined carbon, such as spiegeleisen, which, when dissolved in 
 acid, deposit hydrocarbon oils that are not carried off by the hydrogen 
 evolved. 
 
 Boussingault uses bichloride of mercury in the 
 determination of carbon, for the solution of the 
 iron, which is converted into protochloride of iron, 
 without the decomposition of water, so that no gas is 
 given off capable of combining with the carbon as it is 
 liberated, and the consequent formation of volatile 
 hydrocarbons is avoided. The iron, finely powdered or 
 in filings, mixed with fifteen times its weight of bi- 
 chloride of mercury and sufficient water to form a thin 
 paste, is triturated in an agate mortar for half an hour. 
 When thoroughly incorporated, the paste is transferred 
 to a hard glass flask, and heated to 80 or 100 for an 
 
484 METALLURGY OF IRON. 
 
 hour, when it is thrown on a filter and washed with 
 warm water, to remove the soluble protochloride of 
 iron. The residue on the filter, consisting of proto- 
 chloride of mercury, with carbon and the other insoluble 
 matters of the iron, is dried in a water-bath, transferred 
 to a platinum boat, and introduced into a tube commu- 
 nicating with a generator or gas-holder supplying a 
 stream of dry hydrogen. The tube is gradually heated 
 to redness, when the protochloride of mercury is vola- 
 tilised without decomposition, leaving the carbon in 
 the form of a black powder, which is allowed to cool in 
 hydrogen, and then weighed. When the boat is slightly 
 heated, the carbon fires in the air and burns like tinder ; 
 if, however, graphite is present, it must be burnt in 
 a current of oxygen. The siliceous residue, after the 
 combustion of the carbon, is due to the combined 
 silicon of the iron, but the quantity obtained does not 
 represent the whole amount, because the first action of 
 the bichloride of mercury is to produce chloride of 
 silicon, which is transformed by water into hydrochloric 
 acid and silica, and the latter being partly in the soluble 
 form, passes away with the wash- water, in the filtration. 
 Graphite, or uncombined carbon, is determined in the 
 insoluble residue remaining after solution in hydro- 
 chloric acid, which is digested with a strong solution 
 of caustic potash to remove the silica produced from the 
 oxidation of the silicon. The black residue, after the 
 solution of the silica, is repeatedly washed until per- 
 fectly free from alkali, dried, weighed, and calcined at 
 a strong red heat in a current of air until the whole of 
 the carbonaceous matter is burnt off. The weight of 
 the small amount of residue is then determined, and 
 deducted from that obtained previously. The difference 
 gives the quantity of graphite. The combined carbon 
 
ANALYSIS OF WROUGHT AND CAST IRON AND STEEL. 485 
 
 is obtained by deducting the last result from that of 
 the total amount of carbon obtained by one of the pre- 
 ceding methods. 
 
 Silicon is determined by weighing the insoluble 
 residue of the hydrochloric acid solution after it has 
 been ignited to a strong red heat in a current of air to 
 remove the whole of the carbon. This residue is nearly 
 all silica, but its purity must be tested by dissolving in 
 caustic potash. The insoluble portion, if any, is col- 
 lected, and its weight is deducted from that obtained 
 at the former weighing. 
 
 Determination of Phosphorus. A weighed portion of 
 the metal is digested in aqua regia evaporated to dry- 
 ness, and the residue redissolved in hydrochloric acid* 
 The solution is then treated as in the analyses of iron 
 ores, the determination being made as pyrophosphate 
 of magnesia, or preferably as phospho-molybdate of 
 ammonia. 
 
 Sulphur maybe estimated in grey pig iron by collecting 
 the sulphuretted hydrogen gas evolved by the action of 
 hydrochloric acid, and passing it through a solution of 
 acetate of lead. The precipitate, sulphide of lead, is 
 collected, washed, and converted into sulphate by digest- 
 ing with nitric acid, evaporation to dryness, and gentle 
 ignition. The amount of sulphur is calculated from the 
 weight of sulphate of lead so obtained : it contains 10-55 
 per cent, of sulphur. The above is not applicable to 
 white iron, owing to the difficulty of acting upon it with 
 hydrochloric acid ; but aqua regia may be used, and 
 the sulphur is then directly converted into sulphuric 
 acid, and may be precipitated with chloride of barium, 
 and weighed as sulphate of baryta in the usual way. 
 Another method of oxidising the sulphur consists in 
 fusing the finely-divided metal with nitre and car- 
 
486 METALLURGY OF IKON. 
 
 bonate of soda in a gold crucible ; the fused mass is 
 extracted with water, and the sulphuric acid existing 
 in the solution as an alkaline sulphate is precipitated 
 by chloride of barium as before. 
 
 It is rarely necessary to determine the amount of 
 iron. When required, the volumetric methods by solu- 
 tions of permanganate or bichromate of potassium 
 described under Assaying are to be used. 
 
 Manganese may be determined as in the analysis of 
 ores, or by the special methods on page 494. 
 
 Arsenic and copper are precipitated from the 
 hydrochloric acid solution by sulphuretted hydrogen, 
 care being taken to reduce the whole of the iron to 
 the state of protochloride. The two sulphides may 
 be separated by digestion in sulphide of potassium, 
 which dissolves the sulphide of arsenic, leaving the 
 sulphide of copper untouched. 
 
 Nickel and cobalt, if present, will be found in the 
 solution obtained after the removal of arsenic and 
 copper by sulphuretted hydrogen. The iron is first 
 converted to a persalt, and is then separated as per- 
 oxide by a slight excess of carbonate of baryta ; aften 
 which nickel and cobalt are precipitated by sulphide of 
 ammonium. 
 
 Chromium and vanadium are to be looked for in 
 the carbonaceous residue obtained by dissolving a con- 
 siderable quantity of the iron in weak acid. The 
 ignited residue is fused with nitre at a gentle heat for 
 an hour, and when cooled, the mass is powdered and 
 boiled with water. Yanadate and chromate of potash 
 pass into the solution, are converted, by means of chlo- 
 ride of barium, into the corresponding baryta salts, 
 which are insoluble, and are collected upon a filter. 
 The chromate and vanadate of baryta are decomposed 
 
ANALYSIS OF CAST AND WROUGHT IRON AND STEEL. 487 
 
 with sulphuric acid, whereby chromic and vanadic acid, 
 are set free, and remain as such in the filtrate after 
 separation from the sulphate of baryta. The filtrate is 
 neutralised with ammonia, concentrated by evaporation, 
 and a fragment of chloride of ammonium is placed in it. 
 In proportion as the solution becomes saturated by the 
 latter salt, vanadate of ammonia is deposited as a white 
 or yellowish crystalline powder, which may be collected 
 and subjected to further treatment by the blowpipe or 
 otherwise, in order to verify its properties. The chromic 
 acid is precipitated from the solution by means of 
 acetate of lead as a yellow chromate of lead. 
 
 Eggertz's methods of determining small quantities 
 of sulphur and phosphorus may be conveniently used 
 for estimating these substances in pig irons of high 
 quality, such as those produced in Sweden, but are not 
 applicable to the bulk of the iron produced with minera] 
 fuel from the ores of stratified deposits. 
 
 For sulphur, one-tenth of a gramme of finely- 
 divided pig iron is placed in a stoppered bottle, with 
 1 gramme of water and half a gramme of sulphuric 
 acid. A clean bright plate of silver is suspended by a 
 wire in the upper part of the bottle, and the discolors 
 tion in a given time (about fifteen minutes) is propor- 
 tional to the amount of sulphuretted hydrogen evolved. 
 As this is very small, the plate, instead of being 
 blackened, is tarnished with thin films, presenting the 
 same order of colour as those observed in tempering 
 steel according to their thickness, varying from straw- 
 yellow to bright blue. No absolute measure of quan- 
 tity IK obtained, the results being determined by com- 
 paring the colour on the plate with a standard series, 
 obtained previously by experimenting upon samples 
 whose composition has been determined by analysis 
 
488 METALLURGY OF IRON. 
 
 Thus, a blue colour indicates that the metal will yield 
 a sensibly red-short iron when converted into malleable 
 iron in the hearth finery ; but if the plate is only 
 browned, the sulphur is not in sufficient quantity to 
 affect the quality of the iron. 
 
 In the determination of small quantities of phos* 
 phorus, 1 gramme or 15 grains of the iron or steel 
 to be examined is reduced to a fine powder, and 
 treated with strong nitric acid at the heat of boiling 
 water. When the metal is dissolved, the solution is 
 evaporated to dryness, the residue moistened with 4 
 cubic centimetres of aqua regia made of equal volumes 
 of hydrochloric and nitric acids. After standing for 
 about an hour, an equal volume of water is added, and 
 the solution filtered. The filtrate and wash-water 
 should not exceed 20 cubic centimetres. 
 
 The precipitation of the phosphoric acid is effected 
 by a solution of molybdate of ammonia, containing 
 60 milligrammes of molybdic acid per cubic centi- 
 metre. It is added to the solution of the iron in the 
 proportion of 2 cubic centimetres per milligramme of 
 phosphorus supposed to be present, and digested, with 
 occasional stirring, at about 40 for three hours. If 
 no precipitate is formed, a further addition of molyb- 
 date of ammonia is made. The yellow crystalline 
 precipitate, which contains 1-63 per cent, of phosphorus, 
 is collected in a filter, washed with water acidified 
 with nitric acid, and weighed after drying in a water 
 bath. If, however, the quantity is very small, the 
 determination may be made by measuring the volume 
 of the precipitate in a narrow glass tube with a scale 
 made especially for the purpose. 
 
 The whole of the necessary materials for deter- 
 mining sulphur and phosphorus by these methods is 
 
ANALYSIS OF CAST AND WROUGHT IRON AND STEEL. 489 
 
 supplied with the apparatus made in Sweden for the 
 assay of iron ores by the dry way in the small crucibles 
 mentioned previously. 
 
 Eggertz's method of determining combined carbon 
 in iron or steel depends upon the discoloration pro- 
 duced by carbon in solution of pernitrate of iron, 
 which, under ordinary circumstances, is colourless, or at 
 most of a slightly greenish tint. The standard series 
 of colours is made by dissolving quantities weighing 
 1 decigramme of steel of known composition in nitric 
 acid at a low temperature, and diluting with water to a 
 standard volume. The solutions, which give different 
 shades of brown, are preserved in glass tubes. 
 
 A similar weight of the steel to be examined is dis- 
 solved in pure nitric acid under the conditions observed 
 in making the standard series. The solution is de- 
 canted from the residue, poured into a burette of the 
 same diameter as the tubes containing the standard 
 series, and diluted with water until it matches one of 
 the tints. The amount of carbon is then found by 
 calculation from the relative volumes of the solutions. 
 Steel, with a medium amount of carbon, say O8 per 
 cent., gives a yellowish- green solution ; a very hard 
 variety, with 1*5 per cent., brownish red ; and the softest, 
 with 0'40 per cent., only a slight greenish tinge. 
 
 The Swedish classification of Bessemer steel bv 
 
 V 
 
 numbers, based upon the percentage of carbon deter- 
 mined by the above process, is as follows : 
 
 No. 1 contains 2 per cent. ; No. 1-5, 1*75 ; No. 2, 
 1*5 ; and so on up to No. 4*5, with only 0-25 per cent., 
 below which point the scale is not extended. 
 
 The following determinations of carbon in various 
 kinds of iron and steel made in Sweden are by 
 Eggertz : 
 
490 
 
 METALLURGY OF IHtiS. 
 
 Softest Swedish. Bessemer iron contains 0-08 
 
 Soft steel 
 
 Best quality of cast steel 
 
 Natural forge steel . 
 
 Cement steel . 
 
 Cast steel 
 
 Hardest welding cast steel 
 
 Malleable cast iron . 
 
 Draw-plate steel 
 
 per cent, of carbon. 
 
 0-75 
 
 1-4 to 1-5 
 
 0-99 2-44 
 
 0-5 1-90 
 
 0-86 1-94 
 
 1-80 
 
 0-88 1-52 
 
 3-30 
 
 The following modification of this process is adopted 
 at Seraing, in Belgium, for the determination of carbon 
 in mild Bessemer steel. Two samples, each weighing 
 0*2 grammes, of the ingot to be tested are taken ; one 
 being in the state of filings, and the other of borings. 
 These are treated with 20 cubic centimetres of nitric 
 acid, of specific quartz 1*2 ; the solution being effected 
 in a water-bath at 80. For the test-standard the same 
 weight of two different samples, of the hardest steel 
 made in the works, whose carbon has been already 
 determined, and containing 0'61 and 0'63 per cent, 
 respectively, are dissolved up in the same manner. The 
 whole of the four solutions are then brought down to 
 one tint by adding water to the darker ones, care being- 
 taken to conduct the operation in tubes of exactly the 
 same diameter. The amount of carbon can then be 
 computed from the volume of the solutions. If the 
 difference in the results given by the two samples does 
 not exceed 0'03 per cent., the arithmetical mean 
 between them is adopted as the true amount ; but 
 should it be larger, the operation is repeated. 
 
 In order to obviate the necessity of making standard 
 solutions for every set of determinations, different 
 coloured liquids have been employed with a view of 
 obtaining a permanent scale of colours. Among these 
 may be mentioned caramel, or burnt sugar, which gives 
 
ANALYSIS OF CAST AND WROUGHT IRON AND STEEL. 491 
 
 various shades of yellow and brown, but alters very 
 quickly ; and partially decomposed solution of indigo in 
 sulphuric acid, which is said to keep its characteristic 
 colour without alteration for a considerable time. An- 
 other recommended by Hetman consists of a mixture 
 of bichromate of potash and nitrate of cobalt. In 
 most cases, however, the direct system of comparison 
 with solutions obtained from steel of known composi- 
 tions is to be preferred. 
 
 Silicon. The determination of silicon in iron and steel 
 is a matter of some difficulty, as the mere weighing 
 of the ignited insoluble residue from the hydrochloric 
 acid solution and calculation of the silica found, as 
 silicon, depends upon the assumption that the iron is 
 free from silicates, which is often contrary to the fact, 
 especially in malleable iron, which may contain a 
 notable amount of intermingled slag that has not been 
 perfectly expelled in the welding, and exists as a 
 mechanical inpurity, having no relation whatever to 
 the real composition of the metal. This defective 
 interpretation of the ultimate analyses is probably the 
 cause of the contradictory statements current as to 
 the amount of silicon that may be present beneficially 
 in malleable iron. Eggertz has introduced a method 
 of determining silicon in the presence of slags, which is 
 based upon the fact that when iron is slowly acted upoiv 
 by bromine, a solution of iodine, it dissolves, and the 
 silicon set free is converted into silica, which is com- 
 pletely soluble in a boiling solution of carbonate of 
 soda, while that in combination in the slag, if any be 
 present, is not acted upon. The same method may be 
 employed with cast iron, as blast furnace slag, which 
 sometimes occurs in it as a mechanical impurity is not 
 
492 METALLURGY OF IRON. 
 
 sensibly acted upon either by iodine, bromine, or car- 
 bonate of soda. 
 
 The process is conducted as follows. Three grammes 
 or 45 grains of iron in the state of filings or 
 borings, sufficiently small to pass through a sieve with 
 meshes TIT of an inch indiameter, is treated with five 
 times its weight of iodine, in a volume of fifteen cubic 
 centimetres of water contained in a beaker of about six 
 or seven times that capacity. Water that has been 
 boiled to free it from air is used, and the operation 
 must be performed at as low a temperature as possible, 
 in order to prevent oxidation of the iron by the air, it 
 is usual, therefore, to keep the beaker cool by the use 
 of ice. When the iron is completely dissolved, the 
 solution is increased to three times the original volume 
 by the addition of very cold water in order to prevent 
 the separation of basic salts of iron, and is well stirred 
 and left to settle. The lighter scales of graphitic 
 carbon remain in suspension, and are poured off with 
 the bulk of the liquid into a filter 2 inches in diameter, 
 with only about one-tenth of the original quantity of 
 the insoluble residue which forms a heavy powder at 
 the bottom of the beaker. A few drops of hydro- 
 chloric acid are added, and the liquid stirred 
 with a glass rod: if this produces a disengagement 
 of gas the whole of the iron is not dissolved, and a 
 little iodine and carbonate of soda is added in 
 order to complete the solution. The acidified water 
 must be poured quickly on the filter in order to pre- 
 vent the decomposition of the slag. When the whole 
 of the residue is transferred to the filter it is washed 
 with cold water until the whole of the iron is found to 
 be completely removed when tested by a solution of 
 ferrocyanide of potassium. The filtrate is evaporated 
 
ANALYSIS OF CAST AND WROUGHT IRON AND STEEL. 493 
 
 to dryness with the addition of hydrochloric acid in 
 order to recover any small amount of silica that may 
 have gone into solution with the iron. The original resi- 
 due which may contain graphite, silica, and slag is trans- 
 ferred without drying into a large platinum crucible, 
 and after concentrating the wash-water to 6 cubic 
 centimeters, a saturated solution of carbonate of soda is 
 added, and the crucible is heated for one hour in a 
 water-bath, the liquid being stirred from time to time 
 with a platinum spatula in order to divide any lumps in 
 the insoluble residue. The solution is then carefully 
 poured from the insoluble mass in the crucible on to a 
 small filter, and a fresh quantity of carbonate of soda 
 solution is added and boiled for another hour, when 
 the whole contents of the crucible are thrown upon 
 the filter and washed. The alkaline solution of silica 
 is acidified with hydrochloric acid, added to that 
 containing the iron, and evaporated to dryness in a 
 water-bath. This operation is repeated with the 
 addition of fresh acid until the silica is perfectly freed 
 from iron, when it is filtered, dried, ignited, and 
 weighed as often as may be necessary to ensure its 
 complete purity, which must be further tested by 
 heating it with hydrochloric acid. When 3 grammes 
 of iron are treated, 0*016 grammes of silica correspond 
 to 0.001 gramme of silicon. The insoluble residue from 
 the carbonate of soda solution may contain graphite 
 slag, oxide of iron, and titanic acid. There is no way 
 of distinguishing the amount of oxide of iron present 
 as such, in addition to that in combination with silica, 
 except by assuming the composition of the slag to be 
 constant, which is not the case. 
 
 Eggertz found by the use of this process, that the 
 amount of silicon in good bar iron may vary from O'Ol to 
 
494 METALLURGY OF IRON. 
 
 O10 per cent. ; but in two samples of Krupp's cast 
 steel it was as high as 0'30 per cent. Slag has been 
 found usually in mere traces in cast steel, but in one 
 instance it amounted to 0'2 per cent. Malleable iron, 
 however, contained much more. In wire iron from a 
 charcoal hearth 0-33 per cent, was found, in armour- 
 plates from 0-75 to 3'00 per cent., and in a rail as much 
 as from 4-00 to 5-00 per cent. 
 
 Special Methods of Determining Manganese. Accord- 
 ing to Pattinson, manganese is completely precipitated 
 as hydrated dioxide from a hydrochloric acid solution 
 when a certain proportion of ferric chloride is present, by 
 the addition of solution of bleaching powder, or bromine, 
 and carbonate of lime in excess, at a temperature of 
 60 to 70 degrees. The dark brown precipitate, when 
 filtered and washed until all traces of chlorine or 
 bromine are removed, is transferred on the filter to a 
 beaker containing a measured volume of a solution of 
 ferrous sulphate in sulphuric acid, whose contents of 
 iron are known, in which it readily dissolves, the 
 manganese dioxide producing manganous sulphate, 
 and converting its equivalent of ferrous into ferric sul- 
 phate. The amount of ferrous sulphate remaining in 
 the solution is then ascertained by a standard solution 
 of bichromate of potash, as in the assaying of an iron 
 ore. The difference gives the amount peroxidised by 
 the second atom of oxygen in the manganese dioxide, 
 and from it the amount of the latter metal is calcu- 
 lated according to the following equation : 
 
 2 FeO SO 3 -f MnO 2 -f 2 SO 3 = MnO SO 3 -f- Fe 2 3 3 SO 3 , 
 each unit of ferrous salt corresponding to 0*18 of 
 its weight of manganese. In determining the standard 
 of the iron salt solution a filter of the same size as that 
 used in separating the manganese should be added, in 
 
ANALYSTS OF CAST AND WROUGHT IRON AND STEEL. 495 
 
 order to compensate for any possible reducing action 
 of the paper. The original solution should contain at 
 least half as much iron as manganese. The method is 
 equally applicable to the analysis of ores or metal. 
 
 In America the precipitation of manganese as dioxide 
 by boiling a nitric acid solution with chlorate of potash 
 is much used in the analysis of pig iron and steel. In 
 the former case carbon and silicon must be removed by 
 a preliminary filtration of the nitric acid solution 
 through asbestos, but with steel this is not neces- 
 sary. The precipitated manganese dioxide is filtered 
 upon asbestos, and after washing is dissolved in dilute 
 sulphuric acid in the presence of a known excess of a 
 standard solution of oxalic acid, the amount of which 
 remaining unchanged is determined by a standard 
 solution of permanganate of potash. The reaction is : 
 
 MnO 2 + SO 3 + C"0 3 = MnO SO 3 + 2 CO 2 , 
 each unit of oxalic acid corresponding to 0-763 of its 
 weight of manganese. This method is proposed by 
 F. H. Williams, who recommends the use of a perman- 
 ganate solution of which one cubic centimetre corre- 
 sponds to one milligramme of iron and one of oxalic 
 acid, requiring three times its volume of the former 
 solution to oxidise it. 
 
 Ford adopts a direct method of determination in 
 connection with this process. The precipitated dioxide 
 of manganese is dissolved in hydrochloric acid, ren- 
 dered nearly neutral with ammonia ; acetate of soda is 
 added, and the solution is boiled and filtered. An 
 excess of phosphate of soda and ammonia is added to 
 the filtrate, which is made slightly ammoniacal, when 
 on stirring a finely crystalline precipitate of phosphate of 
 ammonia and manganese goes down, which on ignition 
 is converted into pyrophosphate of manganese. 
 
496 METALLURGY OF IRON. 
 
 CHAPTER XX. 
 
 MECHANICAL PROPERTIES AND TESTS OF MALLEABLE IRON 
 AND STEEL. 
 
 THE quality and character of malleable iron or steel 
 may to some extent be judged by the appearances pre- 
 sented by fractured surfaces, which are fibrous and com- 
 paratively dull in the softer kinds, while in the harder 
 ones they are brilliant and granular or crystalline in 
 various degrees. The fineness and uniformity of the 
 grain is most marked in the harder varieties of tilted 
 cast steel, especially those containing tungsten and man- 
 ganese in considerable quantity, which are nearly glassy 
 in fracture, while un wrought ingots are usually of 
 coarsely crystalline structure, somewhat resembling 
 that of antimony. The nature of the fracture may vary, 
 however, with the manner in which the rupturing strain 
 is applied. If this be very sudden the broken surfaces 
 are almost invariably crystalline, as is seen in coupling 
 hooks and pins broken in railway accidents, although 
 they are usually made of iron which ordinarily shows 
 a fibrous fracture when broken by strains progres- 
 sively augmented. The crystalline structure of melted 
 or balled iron or steel is very considerably modified by 
 the process of lamination, the crystalline masses be- 
 coming distorted and elongated by the action of the 
 rolling-mill, fibre being developed in the direction of 
 the length of the bar. At each successive piling the 
 grain becomes finer and more regular, owing to the 
 breaking down and rewelding of the fibres in the bars 
 forming the pile. Tresca has compared the effect 
 of forge rolling to that of the processes of carding 
 and drawing cotton, the result in both cases being 
 
MECHANICAL PROPERTIES AND TESTS. 
 
 497 
 
 the production of parallel fibre. When the work is 
 done upon the metal in a plastic state at a high 
 temperature, the density is increased; but when a 
 powerful tractive strain is exerted, as in wire drawing 
 or planishing bars by cold rolling, the metal elongates 
 more rapidly than its transverse section diminishes, and 
 the density is diminished while the tenacity is consider- 
 ably increased. The softness and lower tenacity, 
 together with the original higher density, may be 
 restored by annealing. 
 
 The changes referred to above are illustrated by the 
 following results taken from Kirkaldy's experiments 
 on wrought iron and steel made at Glasgow in 
 1858 61 ; from which it appears the diminution in 
 specific gravity in bars stretched by a severe tensile 
 strain varied from 0'7 to 1*2 per cent. By cold rolling 
 the diminution amounted to O f 7 per cent, for bars, and 
 0*36 per cent, for plates. 
 
 Mark or Name. Specific Gravil 
 
 y. Tensile Strength. 
 
 Govan puddled bar . . . 7'450 
 
 20 -9 tons per square inch. 
 
 hammered bar . . 7*764 
 
 28-7 
 
 rolled bar, 1 inch, square 7 '720 
 
 25-6 
 
 reduced to 1 inch 7'729 
 
 25-4 
 
 1 7-722 
 
 25-6 
 
 1 7-702 
 
 25-9 
 
 * 7-685 
 
 26-6 
 
 Blochairn best rolled bar . . 7'636 
 
 27-1 
 
 cold rolled. . 7'582 
 
 30-6 to 30-5 
 
 annealed . . 
 
 25-2 to 27-8 
 
 K best boiler plate . 7 "566 
 
 ( 20 -5 lengthways 
 (19-2 cross ways 
 
 cold rolled 7'539 
 
 ( 39-7 lengthways 
 36*0 cross way s 
 
 annealed 
 
 f 22-7 lengthways 
 (21-7 cross ways 
 
498 
 
 METALLURGY OF IROX. 
 
 The same observer found in 1858 61 that the 
 tensile strength of the best brands of British bar iron 
 varied from 24 to 27*5 tons per square inch : bars of 
 irregular section bear a somewhat smaller strain, or 
 from 20 to 27*4 tons. The strength of plates varied 
 from 20*4 to 24 - 6 tons lengthways, or in the direction 
 of the greatest longitudinal extension produced by 
 rolling, and from 18*5 to 22 '6 tons crossways. The 
 specific gravity varies from 7-531 to 7-760, being 
 greatest in Yorkshire iron, which is made almost 
 entirely under the hammer. 
 
 The relation between the composition of malleable 
 iron and steel and their resistance to strains of different 
 kinds has of- late -years been investigated by many 
 observers. The following table, showing the limits of 
 elasticity and tensile strength of various kinds of 
 malleable iron and steel, is taken from one of the 
 earliest of these investigations made in Sweden for the 
 Jernkontor, by Sty fie : 
 
 Percentage of 
 Carbon. 
 
 Specific gravity. 
 Soft. Hardened. 
 
 Tensile strength, 
 tons per square inch. 
 
 1-5 
 1-2 
 0-9 
 0-6 
 
 0-4 
 
 7-785 
 7-832 
 7-874 
 7-879 
 7-893 
 
 7-736 
 7-771 
 
 7-808 
 7-^07 
 7-839 
 
 3439 
 3740 
 5659 
 
 3741 
 3034 
 
 The absolute strength appears to be greatest when the 
 steel contains from 1 to 1 per cent, of carbon. 
 
 The following table contains the relation between 
 the specific gravity and tensile strength of Bessemer 
 steel of various degrees of carburisation made at Sand- 
 viken, in Sweden : 
 
MECHANICAL PROPERTIES AND TESTS. 
 
 499 
 
 Quality of Iron. 
 
 Perceu 
 Carbon. 
 
 tage of 
 Phosphorus 
 
 Limit of ( Breaking 
 Elasticity , stntiu 
 per square inch. 
 
 Hogbb Bessemer steel, rolled bar 
 
 2-16 
 
 
 
 29-8tons 
 
 40 -2 tons 
 
 5) 
 
 1-85 
 
 
 
 26-7 
 
 46-2 
 
 WikmanshyttuTJchatiussteel 
 
 1-22 
 
 
 
 33-8 
 
 66-9 
 
 Carlsdal Bessemer steel . . . 
 
 1-19 
 
 
 
 31-4 
 
 64-8 
 
 ,, Uchatius . . . 
 
 I'M 
 
 
 
 33-2 
 
 64-7 
 
 Hogbo Bessemer . . . 
 
 1-14 
 
 0-018 
 
 39-6 
 
 59-0 
 
 hammered 
 
 0-68 
 
 
 
 31-8 
 
 46-8 
 
 Krupp's cast steel 
 
 0^2 
 
 0-020 
 
 23-7 
 
 39-5 
 
 Hbgbo Bessemer iron . 
 
 033 
 
 
 
 24-1 
 
 33-0 
 
 Low Moor rolled tire bar . . 
 
 0-21 
 
 0-068 
 
 is-? ,; 
 
 27-3 
 
 Lesjofors rolled bar made in | 
 the "Lancashire hearth . ) 
 
 0-06 
 
 0-022 
 
 14-0 
 
 22-5 
 
 An elaborate series of experiments on the effect pro- 
 duced by varying single constituents in steel as regards 
 mechanical properties has been published by the Terre- 
 Noire Company, at the Paris Exhibition, in 1878. The 
 metal investigated was principally open-hearth steel. 
 In the first series five charges were made with different 
 proportions of carbon, phosphorus and manganese 
 being kept as nearly uniform as possible ; in the 
 second series, manganese was varied ; and in the 
 third, phosphorus. These were subjected to the dif- 
 ferent tests of flexure tension, impact, and compression, 
 both in the natural state, and when tempered in water 
 and oil. An abstract of the results obtained with the 
 natural metal is contained in the following table. 
 
 Column F contains the breaking strains of bars 39J 
 inches between the points of support, and loaded in the 
 middle. E, the limits of elasticity. T, the ultimate ten- 
 sile strength, all expressed in tons per square inch. L, 
 the percentage of elongation on the original length of 
 bars broken by tension. I, the energy of blow pro- 
 ducing fracture in foot-lbs. in the falling-weight test. 
 C, compression expressed in loss per cent, of original 
 height, under a load of 200 tons per square inch in the 
 
500 
 
 METALLURGY OF IRON. 
 
 I. Steel varying in Carbon. 
 
 
 
 
 
 
 
 i ' 
 
 
 
 Index 
 ..No. 
 
 Carbon, 
 
 Sili- 
 con. 
 
 Phos- 
 phorus. 
 
 Mn. 
 
 F. 
 
 E. I T. 
 
 L. 
 Per 
 
 I. 
 
 c. 
 
 Per 
 
 
 
 Per cent. 
 
 
 Tons per sq. in. 
 
 cent. 
 
 Ffc.-lbs. 
 
 cent. 
 
 59 
 
 0-150 
 
 
 
 0-035 
 
 0-213 
 
 p 
 
 14-0 
 
 22-7 
 
 34-0 
 
 p 
 
 71-5 
 
 66 
 
 0-490 
 
 
 
 0-070 
 
 0-200 
 
 p 
 
 16-6 
 
 31-0 
 
 24-0 
 
 p 
 
 64-0 
 
 70 
 
 0-709 
 
 
 
 0-062 
 
 0-266 
 
 4-0 
 
 20-1 
 
 43-2 
 
 15-0 
 
 17980 
 
 60-3 
 
 74 
 
 0-875 
 
 
 
 0-055 
 
 0-250 
 
 4-25 
 
 21-7 
 
 47-0 
 
 9-5 
 
 15195 
 
 55'5 
 
 82 
 
 1-050 
 
 
 
 0-063 
 
 0-255 
 
 4-13 
 
 24-9 
 
 54-7 
 
 4-5 
 
 11771 
 
 53-8 
 
 II. Steel varying in Manganese. 
 
 0-450 
 
 
 
 0-067 
 
 0-521 
 
 ? ll7-3[34-3 
 
 24-2 
 
 p 
 
 64-3 
 
 0-467 
 
 
 
 0-072 
 
 1-060 
 
 ? 22-7J41-3 
 
 21-0 
 
 P 
 
 62-4 
 
 0-515 
 
 
 
 0-061 
 
 1-305 
 
 5-4 
 
 27-6 J52-4 115-7 
 
 17980 169-9 
 
 0-560 
 
 
 
 0-058 
 
 2-008 
 
 5-8 
 
 30-9J62-7 
 
 9-5 
 
 16647! 
 
 III. Steel varying in Phosphorus. 
 
 0-310 
 0-274 
 0-310 
 
 0-247 
 0-273 
 0-398 
 
 0-746 
 0-800 
 0-693 
 
 4-13 
 2-92 
 
 21-0 
 21-5 
 23-3 
 
 36-0 
 35-5 
 38-9 
 
 26-2 
 23-5 
 22-2 
 
 ? | 61-9 
 17980 1 57-7 
 13591158-2 
 
 IV. Steel cast without Blow-holes. 
 
 
 t 
 
 0-875 
 
 0-322 
 
 0-085 
 
 0-772 
 
 2-10 
 
 24-9 
 
 41-0 
 
 1-5 
 
 9611 
 
 52-8 
 
 0-750 
 
 0-163 
 
 0-097 
 
 0-672 
 
 2-29 
 
 19-4 
 
 40-3 
 
 3-5 
 
 11771 
 
 57-5 
 
 0-459 
 
 0-221 
 
 0-078 
 
 0-670 
 
 2-35 
 
 16-8 
 
 27-5 
 
 3-0 
 
 11771 
 
 62-6 
 
 0-287 
 
 0-233 
 
 0-076 
 
 0-693 
 
 2-79 
 
 13-3 
 
 28-38 
 
 8-8 
 
 15195 
 
 66-0 
 
 0-450 
 
 0-280 
 
 *0-750 
 
 0-750 
 
 
 23-2 
 
 40-0 
 
 2-2 
 
 
 
 57-5 
 
 Chromium. 
 
 + Oil-tempered samples. 
 
 V. Continuous series, Cast Iron to Steel. 
 
 Tons. 
 
 3-425 
 
 3-540 
 
 0-125 
 
 0-120 
 
 0-83 
 
 
 
 4-56 
 
 
 
 2481 
 
 20-5 
 
 3-351 
 
 1-000 
 
 0-092 
 
 
 
 0-95 
 
 
 
 5-61 
 
 
 
 2865 
 
 32-3 
 
 2-900 
 
 0-990 
 
 0-OS7 
 
 
 
 1-24 
 
 
 
 9-20 
 
 
 
 3738 
 
 49-7 
 
 2-425 
 
 0-938 
 
 0-09L 
 
 0-145 
 
 1-56 
 
 
 
 11-75 
 
 
 
 4052 
 
 62-7 
 
 2-150 
 
 0-700 
 
 0-085 
 
 0-180 
 
 1-84 
 
 
 
 14-15 
 
 
 
 4238 
 
 79-7 
 
 1-530 
 
 0-730 
 
 0-112 
 
 0-160 
 
 1-94 
 
 
 
 15-74 
 
 
 
 3926 
 
 111-1 
 
 series I. to IV., and the crushing strain in tons per 
 square inch in series Y. ? signifies that fracture was 
 not produced by the highest available stress. 
 
MECHANICAL PROPERTIES AND TESTS* 501 
 
 From these experiments it appears that the flexibility 
 of very mild steel, such as No. 59, is greater than that 
 of the best bar iron ; that is, it will stand a greater trans- 
 verse strain without fracture, but it is more rigid, 
 or for equal increments of weight takes a smaller 
 permanent set. The latter was for square bars of the 
 best wrought iron, 4 inches in the side and 39J inches 
 between the bearings, under a strain of 30 tons applied 
 in the centre, 1'6 to 1-9 inches, while for similar bars of 
 No. 59 it was only 0'4 inch. The elasticity and ulti- 
 mate strength appear to be in direct proportion to the 
 amount of carbon, as is also the rigidity, the latter 
 property in the harder varieties appearing as fragility 
 under impact. Increase of manganese has generally 
 the same effect as augmentation of carbon, the elastic 
 limit and ultimate tensile strength being increased, 
 while the elongation before fracture is diminished. 
 
 Chromium has a remarkable influence upon the 
 resistance of the metal to compression. The same test 
 piece of No. 278, when water tempered, and twice sub- 
 jected to a pressure of 200 tons per square inch, was 
 only shortened about 2 -5 per cent. 
 
 Phosphorus, when present in notable quantity in 
 steel, increases the rigidity, and sensibly diminishes 
 the power of resisting impact. Such metal, however, 
 can only be rendered workable by keeping down the 
 proportion of carbon, which is effected in practice by 
 the use of high ferro-manganese, with the necessary 
 result of introducing a large proportion of manganese. 
 This condition is involved in the manufacture of the 
 so-called phosphorus steel, which has been successfully 
 made on the large scale for some time, it being more 
 particularly applied in the remanufacture of old iron 
 rails in the open-hearth furnaces. 
 
502 METALLURGY OF IRON. 
 
 Series IV. contains the tests of steels cast with a con- 
 siderable addition of silicon as well as manganese, 
 which has the property of giving ingots free from blow- 
 holes. This gives a very strong metal suitable in the 
 harder varieties for armour-piercing projectiles. 
 
 Series Y. shows the gradation of cast iron into 
 steel by the progressive diminution of carbon. No. 156 
 is a dark grey pig metal, whose low mechanical re- 
 sistance is to be ascribed to the large amount of 
 silicon present, as No. 164, containing the same amount 
 of carbon, is sensibly stronger. With 2 per cent, of 
 carbon the metal may be hardened by chill casting, but 
 below this point there is not much difference between 
 objects cast in sand or metal moulds. The property of 
 malleability appears in No. 404, with 1*5 per cent, of 
 carbon which can be forged and drawn under the 
 hammer, and also tempered to some extent, and may 
 be considered to be steel, although it is extremely 
 rigid, and breaks under a tensile strain almost without 
 elongation. 
 
 In comparative tests of iron and steel it is essential 
 that all the samples should be subjected to exactly 
 similar treatment; that is, the test- pieces must be of 
 the same dimensions, especially as regards length and 
 thickness. For equal quality of material a thin section 
 gives a proportionately higher resistance per unit 
 of surface than a thicker one. This is especially seen 
 in steel wires, which may be obtained of a tensile 
 strength of 100 to 140 tons to the square inch. The 
 proportional elongation before fracture is also greater 
 with short than with long test-pieces, and the lengths 
 of those used by different investigators vary very 
 considerably ; 4, 6, or 8 inches being, however, com- 
 mon. The figures in the table, on page 500, refer 
 
MECHANICAL PROPERTIES AND TESTS. 503 
 
 to cylindrical pieces of 4 inches long and 0'4 inch 
 diameter. 
 
 Another method of estimating the toughness of steel 
 consists in measuring the area of the fractured sur- 
 face and comparing it with that of the original trans- 
 verse section. These will always differ, the differences 
 being greatest in the softer kinds of metal. Thus thfe 
 difference between the original and fractured surfaces 
 was 65 '7 per cent, in No. 59, while in No. 82 it 
 was only 12'4 per cent. It is matter of controversy 
 whether the toughness of the metal is best evidenced 
 by contraction or by elongation ; the latter is the more 
 convenient test, as the determination of the area of 
 fracture is rather a troublesome process. 
 
 Working Tests. The tensile strength alone is not a 
 sufficient measure of the quality of malleable iron or 
 steel, as, especially with the latter, a metal of great 
 strength may be deficient in softness and incapable of 
 working properly under the hammer. "Whenever, 
 therefore, where the metal is to be subjected to further 
 treatment, such as punching and drilling for riveting 
 holes in boiler or shipbuilding works, special forge 
 tests, both hot and cold, and in the case of steel temper- 
 ing tests, are adopted, examples of which are given 
 below. 
 
 Another useful supplemental test, especially in the 
 case of welded iron, is obtained by polishing a section 
 of the bar or plate, and then etching it with some cor- 
 rosive liquid which brings out the lines of junction of 
 the different elements of the pile and cinder patches or 
 other defects. Either weak hydrochloric acid applied 
 upon blotting paper, or a very dilute solution of chloride 
 of platinum, may be used as an etching fluid. 
 
 Rails which are subjected to heavy percussive strains 
 
504 METALLURGY OF IRON. 
 
 in use are tested in England for safety by allowing a 
 heavy weight to fall upon them from a height which 
 varies with the weight per yard and the character of 
 the metal. For iron rails, according to Sandberg, a 
 proper safety- strength is given by the product of the 
 weight in cwts. into the fall in feet which should 
 equal the weight per yard. Thus a 56-lb. rail 
 supported on bearings 3 feet apart should not be 
 indented more than f inch to 1 inch by a weight of 
 7 cwt. falling 8 feet. For steel rails a heavier weight 
 and higher fall are necessary to prevent the use of too 
 hard a metal, and the former is therefore increased to a 
 ton and the latter to 15 feet with light or 20 feet with 
 heavy sections. 
 
 The prescription of a particular chemical composition 
 for steel rails has been proposed by Dr. Dudley for the 
 Pennsylvania Railway Company, in America, who 
 gives us the following as permissible limits : 
 Phosphorus, not above . ; CTS V ^ 0-10 per cent. 
 Silicon ... 0-04 
 
 Carbon 0-25 to 0-35, preferably . 0'30 
 Manganese 0-30 to 0'40, . 0-35 
 Sulphur and Copper . . . not specified. 
 Other impurities <} e . . ::-w. ,i . only traces. 
 Minimum tensile strength, 29 tons per square inch. 
 Minimum elongation, 20 per cent. 
 
 This specification is founded upon the results of the 
 analysis of a considerable number of worn rails, some 
 of which had broken in use while others had not. At 
 the same time the theory was propounded that the 
 hardening properties of phosphorus, silicon, carbon, 
 and manganese were to each other in the proportion 
 of 1 : : J : -Jr, and that the sum of the phosphorus and 
 of the respective fractions of the other constituents 
 
MECHANICAL PROPERTIES AND TESTS. 505 
 
 expressed in hundredths per cent, gave a measure of 
 the hardness in so-called phosphorus units. By this 
 method the number of such units in good rails varied 
 from 20 to 36, while in those that broke in use it 
 varied from 33 to 53. This theory has, however, not 
 found general acceptance, mainly from its being founded 
 upon too small a number of observations ; but the con- 
 clusion that great hardness is detrimental to the wear- 
 ing power of steel rails accords with the previous 
 experiments of J. T. Smith, who found that on the 
 Furness line the loss of weight of rails that had been 
 eight years in use averaged only 13*54 per cent, when 
 the steel contained 0-30 per cent, of carbon, while with 
 harder ones with 0*44 per cent, of carbon the average 
 wear was 15-18 per cent. 
 
 The German Union of Railway Managers in 1880 
 proposed the following scheme of classification for 
 steel used in railway materials, which has subsequently 
 been adopted in its main points by the German and 
 Austrian Government lines : 
 
 1. According to quality and temper : 
 
 First Class. Kilogrammes Contraction Qualitative 
 
 per cent. factor. 
 
 25 90 
 
 35 90 
 
 45 90 
 
 20 75 
 
 30 75 
 
 30 90 
 
 25 90 
 
 55 90 
 
 20 85 
 
 The qualitative factor in the last column is the sum 
 z 
 
 per sq. m.m. 
 
 Hard . tensile strength 
 
 65 
 
 Medium 
 
 
 
 55 
 
 Soft . 
 
 
 
 45 
 
 Second Class. 
 
 
 
 Hard . 
 
 
 
 55 
 
 Soft . 7 
 
 ,, ,, 
 
 45 
 
 2. According to uses : 
 
 
 Axles . . tensile strength 
 
 50 
 
 Engine tyres ,, ,, 
 
 60 
 
 Carriage and waggon | 
 
 45 
 
 tyres . J 
 
 
 Kails . 
 
 50 
 
506 
 
 METALLURGY OF IRON. 
 
 of the other two with in some cases the addition of an 
 arbitrary quantity. 
 
 The above scheme, which is based on the tensile 
 strength only, is by many persons regarded as unsuited 
 for practical requirements, and the Society of German 
 Ironmasters has propounded a more complete one, as 
 being better fitted for the use of both producers and 
 consumers. An abstract of this will be found in the 
 Proceedings of the Institute of Civil Engineers, vol. 
 Ixvii., p. 484. 
 
 The following are the tests prescribed by the 
 Admiralty for plate iron intended for use in the 
 navy, and may be taken as indicating the average 
 strength of iron of fair quality : 
 
 PLATE IRON V FIRST GL 
 
 &.S8, OR B.B. 
 
 SECOND CLASS, ORB. 
 
 Lengthways. 
 
 Crossways. 
 
 Lngthwys. 
 
 Crossways. 
 
 Tensile strength, per square inch, 22 tons 
 
 18 tons 
 
 20 tons 
 
 17 tons 
 
 Forge test, hot. All plates of 1 
 
 
 
 
 
 inch in thickness and be- 
 
 
 
 
 
 low must be capable of 
 
 125 
 
 90 
 
 00 
 
 60 
 
 bending hot without frac- 
 
 
 
 
 
 ture through an angle of J 
 
 
 
 
 
 Forge test, cold. Plates should 
 
 
 
 
 admit of bending cold with- 
 
 
 
 
 out fracture as follows : 
 
 
 
 
 
 1 in. in thickness to an angle of 15 
 
 5 
 
 10 
 
 
 
 5 ? 5 
 
 25 
 
 10 
 
 20 
 
 5 
 
 2 5> 
 
 35 
 
 15 
 
 30 
 
 10 
 
 A" J) 
 
 70 
 
 30 
 
 55 
 
 20 
 
 inch and under 
 
 90 
 
 40 
 
 75 
 
 30 
 
 Plates should be tested, both hot and cold, on a cast- 
 iron slab having a fair surface, with an edge at right 
 angles, the corner being rounded off with a radius of 
 half an inch. 
 
 The portion of plate tested to be 4 feet in length 
 across the grain, and the full width of the plate with 
 
MECHANICAL PROPERTIES AND TESTS. 507 
 
 the grain. The bend should be made from 3 to 6 
 inches from the edge. 
 
 All plates to be free from lamination and injurious 
 surface defects. 
 
 The tests to be applied to one plate of each lot of 
 fifty of the same thickness. 
 
 The tests specified for steel are as follows : 
 
 Strips cut lengthwise or crosswise to have an ulti- 
 mate tensile strength of not less than 26 or more than 
 30 tons per square inch of section, with an elonga- 
 tion of 20 per cent, in a length of 8 inches. 
 
 Beam, angle, bulb, and bar steel to satisfy such 
 forge tests, hot and cold, as may be sufficient to prove 
 soundness of material and fitness for service. 
 
 Strips cut crosswise or lengthwise 1J inches wide, 
 heated uniformly to a low cherry-red heat, and cooled 
 in water at 82 Fahr., must stand bending in a press to 
 a curve whose corner radius is 1 J times the thickness 
 of the plate. 
 
 The strips are all to be cut in a planing machine, 
 and to have the sharp edges taken off. 
 
 The durability of every bar or plate supplied to be 
 ascertained by the application of one or both of these 
 tests to the shearings, or by cold bending under the 
 hammer. 
 
 All steel to be free from lamination and injurious 
 surface defects. 
 
 Lloyd's rule specifies 27 to 31 tons as the limit of 
 tensile strength, with an elongation of 16 per cent, 
 on 8 inches for steel ship plates. Angle iron must 
 bear flattening under the hammer and doubling back 
 cold. In other respects the tests are similar to those 
 of the Admiralty. 
 
SUPPLEMENTARY NOTES. 
 
 CLEVELAND BLAST FURNACES. 
 
 The following table recently published by Gjers shows the progres- 
 sive increase in size in the Cleveland Blast Furnaces, giving their 
 dimensions and capacity in the order of their respective dates : 
 
 Date. 
 
 Name of Firm. 
 
 Furnaces. 
 
 Hei ^- "Ss of Ca p-*y- 
 
 
 
 No. 
 
 Feet. Feet. Cubic feet. 
 
 1851 
 
 Bolckow and Vaughan: 
 
 3 
 
 42 15 
 
 4,566 
 
 1853 
 
 Bell Brothers. 
 
 6 
 
 47! j 16! 
 
 6,174 
 
 ' 
 
 Bolckow and Vaughan. 
 Gilkes, Wilson, and Co. 
 
 6 
 
 2 
 
 54 
 45| 
 
 15 
 14* 
 
 7,166 
 5,100 
 
 1854 
 
 Cochrane and Co. 
 
 4 
 
 55 
 
 16 
 
 7,175 
 
 
 B. Samuelson and Co. 
 
 3 
 
 50 
 
 14 
 
 5,050 
 
 ,, 
 
 Bolckow and Vaughan. 
 
 3 
 
 54 
 
 15 
 
 7,116 
 
 
 Gilkes, Wilson, and Co. 
 
 2 
 
 55 
 
 14! 
 
 6,800 
 
 1856 
 
 Stockton Furnace Co. 
 
 3 
 
 50 
 
 16 
 
 6,341 
 
 
 Norton Iron Co. 
 
 3 
 
 50 
 
 15 
 
 6,000 
 
 1858 
 
 Thomas Vaughan. 
 
 6 
 
 56 
 
 16 
 
 7,000 
 
 M 
 
 Hopkins, Gil'kes, and Co. 
 
 2 
 
 56 
 
 16 
 
 7,200 
 
 
 Jones, Dunning, and Co. 
 
 2 
 
 58 
 
 17 
 
 8,000 
 
 
 Bolckow and Vaughan. 
 
 1 
 
 61 
 
 Mf 
 
 7,960 
 
 1861 
 
 Gilkes, Wilson, and Co. 
 
 1 
 
 55 
 
 16 
 
 7,700 
 
 >? 
 
 William Whitwell and Co. 
 
 3 
 
 60 
 
 20 
 
 12,778 
 
 1862 
 
 Bolckow and Vaughan. 
 
 2 
 
 75 
 
 16! 
 
 11,985 
 
 1864 
 
 B. Samuelson and Co. 
 
 4 
 
 69 
 
 20 
 
 15,500 
 
 
 Lloyd and Co. 
 
 4 
 
 67 
 
 20 
 
 15,000 
 
 
 
 Thomas Vaughan. 
 Stevenson, Jacques, and Co. 
 
 6 
 3 
 
 81 
 70 
 
 19 
 22 
 
 16,000 
 17,000 
 
 1865 
 
 Gilkes, Wilson, and Co. 
 
 2 
 
 75 
 
 21 
 
 17,700 
 
 
 Bell Brothers. 
 
 2 
 
 80 
 
 20| 
 
 15,500 
 
 
 
 Bolckow and Vaughan. 
 
 2 
 
 95! 
 
 16 
 
 15,050 
 
 1866 
 
 
 Bolckow and Vaughan. 
 Hopkins, Gilkes, and Co. 
 Swan, Coates, and Co. 
 
 1 
 2 
 2 
 
 75 
 75 
 75 
 
 20 
 24 
 20 
 
 12,972 
 20,000 
 16,090 
 
 
 Bell Brothers. 
 
 2 
 
 80 
 
 17 
 
 11,500 
 
 1867 
 
 Norton Iron Co. 
 
 2 
 
 85 
 
 25 
 
 26,000 
 
 >? 
 
 Cochrane and Co. 
 
 2 
 
 76 
 
 23 
 
 20,624 
 
 1868 
 
 Gilkes, Wilson, and Co. 
 
 1 
 
 75 
 
 24 
 
 22,500 
 
 || 
 
 Stevenson, Jacques, and Co. 
 
 1 
 
 70 
 
 23 
 
 18,000 
 
 
 B. Samuelson and Co. 
 
 1 
 
 69 
 
 21! 
 
 16,000 
 
 j> 
 
 Lloyd and Co. 
 Jones, Dunning, and Co. 
 
 2 
 3 
 
 80 
 73 
 
 21! 
 18 
 
 18,000 
 12,000 
 
 
 Bolckow, Vaughan, and Co. 
 Bolckow, Vaughan, and Co. 
 
 2 
 1 
 
 86* 
 
 95| 
 
 22 
 23 
 
 25,940 
 28,800 
 
 18G9 
 
 Thomas Vaughan. 
 
 3 
 
 85 
 
 25 
 
 26,000 
 
 1870 
 
 Bell Brothers. 
 
 4 
 
 80 
 
 25 
 
 25,000 
 
 
 Stockton Furnace Co. 
 
 2 
 
 80 
 
 24 
 
 24,613 
 
 i 
 
 Swan, Coates, and Co. 
 
 1 
 
 75 
 
 28f 
 
 22,229 
 
 
 Cochrane and Co. 
 
 2 
 
 90 
 
 30 
 
 41,149 
 
 
 Gilkes, Wilson, and Co. 
 
 2 
 
 85 
 
 27 
 
 32,000 
 
 ?J 
 
 B. Samuelson and Co. 
 
 2 
 
 85 
 
 28 
 
 30,000 
 
 1871 
 
 Bolckow, Vaughan, and Co. 
 Lackenby Iron Co. 
 
 2 
 2 
 
 95! 
 
 85* 
 
 24 
 25! 
 
 28,950 
 26,670 
 
 r " 
 
 Gjers, Mills, and Co. 
 
 2 
 
 85 
 
 25 
 
 26,000 
 
SUPPLEMENTARY NOTES. 
 
 509 
 
 PURPLE ORE OR BLUE BILLY. 
 
 For the ibllowing analysis of " purple ore," I am indebted to Mr. 
 J. A. Phillips, the managing director of the Widnes Metal Company. 
 It is obtained from the residues of cupriferous iron pyrites, which have 
 been treated for sulphur in the manufacture of sulphuric acid, calcined 
 with an addition of salt, and lixiviated with water, in order to save 
 the copper, which is removed as a soluble chloride, and is precipitated 
 as cement copper by running the solution into vats, containing scrap 
 iron. The residue of these operations is nearly pure peroxide of iron 
 in the form of a heavy purplish-rei powder, having the following 
 composition : 
 
 Peroxide of iron . . . 
 Lead (as sulphate) . . 
 Copper ..... 
 Sulphur .... 
 Phosphorus .... 
 
 Lime 
 
 Soda 
 
 Cobalt, arsenic, and chlorine 
 Insoluble residue 
 
 Metallic Iron 
 
 96-00 
 0-75 
 
 None. 
 
 0.40 
 
 O'lO 
 Traces. 
 
 2-11 
 
 99-92 
 67-00 
 
 The results are computed in the dry state, but, as ordinarily sold, 
 the ore contains about 15 per cent, of water. It is principally used for 
 fettling puddling furnaces, but is also smelted to some extent, being 
 added to the charge in the blast furnace in the proportion of 25 per 
 cent, of the amount of solid ore. 
 
 COMPOSITION OF THE GASES OF THE BESSEMER, CONVERTER. 
 
 The nature of the gases evolved during the blowing of a charge of 
 Bessemer steel has recently been investigated by Mr. G-. J. Snelus, who 
 has given the following tabular statement of the composition of the 
 gas at different periods of a blow lasting eighteen minutes. 
 
 i. ii. ni. iv. v. vi. 
 
 Time from starting 2 min. 4 min. 6min. 10 min. 12min. 14 min. 
 
 Carbonic acid 
 Carbonic oxide 
 Oxygen 
 Hydrogen 
 Nitrogen 
 
 100-00 100-00 100-00 100-00 100-00 100-00 
 
 On examining these results it is found that the oxygen correspond- 
 ing to the nitrogen in Analysis I. is sufficient to oxidize not only the 
 
 10-71 
 
 8-57 
 
 8-20 
 
 3-58 
 
 2-30 
 
 1-34 
 
 none. 
 
 3-95 
 
 4-52 
 
 19-59 
 
 29-30 
 
 31-11 
 
 0-92 
 
 
 
 
 
 
 
 
 
 
 
 88-37 
 
 o-ss 
 
 2-00 
 
 2-00 
 
 2-16 
 
 2-00 
 
 
 86-58 
 
 85-28 
 
 74-83 
 
 66-24 
 
 65-55 
 
510 METALLURGY OF IRON. 
 
 4'43 parts by weight of carbon that are contained in the gas, but also 
 11-91 parts of silicon, and this is actually the proportion in which, 
 these two substances are eliminated from the iron, as proved by 
 analysis of samples of metal taken at this stage. Analysis III. shows 
 that 5-27 parts of carbon are burnt along with 11-74 of silicon. 
 Analysis IV. of gas taken after the commencement of the boil, shows 
 a different result ; the large proportion of carbonic oxide accounts for 
 the increased luminosity of the flame, and the removal of carbon pro- 
 ceeds in the ratio of 9 - 6 parts of 6-25 of silicon. No. V. was specially 
 tested for hydrocarbons, but none were found. No. VI. gives the 
 proportion of 13-45 of carbon oxidized to 0*46 of silicon, thus confirm- 
 ing what has already been made out by analyses of the metal, that the 
 last traces of silicon are oxidized very slowly. 
 
 Snel us considers that the production of carbonic acid during the first 
 part of the blow, and carbonic oxide at a later stage, is due to the 
 increase of temperature during the blow, and that the result agrees 
 with those of the experiments of J. L. Bell, who found that at a low- 
 temperature carbonic acid, in contact with iron, was more stable than 
 carbonic oxide ; but that at a high temperature, the reverse was the 
 case. He also considers that the continuous spectrum produced by the 
 flame at the commencement of the blow is to be accounted for by the 
 fact that at this period there is no true flame, but only a stream of 
 gases containing white hot solid matter in suspension, while at the 
 same time the temperature is not sufficiently high to give the spectrum 
 of carbonic acid. Later on in the blow, when there is an abundance of 
 carbonic oxide burning at the mouth of the converter, the temperature 
 is extremely high, and consequently a carbon spectrum is produced 
 which is distinct from other carbon spectra yet seen, because the 
 spectrum of carbonic oxide has not yet been observed at the particular 
 temperature of the Bessemer flame. The heating power of the gas in 
 the latter part of the blow is fully equal to that of the blast furnace, 
 or Siemens' producer, and Snelus computes that in works blowing 
 1,000 tons of pig iron per week, an amount of heat is wasted, which 
 supposing it could be utilised, would correspond to a saving of 25 tons 
 of coke per week. 
 
 At Brown, Bayley, and Dixon' s works, Sheffield, the waste flame is 
 passed through a chamber containing cast-iron syphon-pipe stoves 
 and heats the blast required for the pig-iron remelting cupolas. By 
 this arrangement the consumption of coke has been reduced to 
 If cwt. per ton of metal melted. 
 
SUPPLEMENTARY NOTES, 611 
 
 THE CONSTITUTION OF IKON AND STEEL 
 
 The conditic a ander which, carbon exists in steel has been investi- 
 gated by Sir I", ^vbel, who reports his conclusions to the Institution 
 of Mechanical i agineers, 1887, as follows : 
 
 ' ' In annealed steel carbon exists entirely, or nearly so, as a carbide 
 of iron, FesC, uniformly diffused through the mass of metallic iron, 
 while in hardened steel the same compound if present is only obtained 
 in very small quantity, the carbon being practically all combined. 
 Tempered steel is intermediate in character, the proportion of carbide 
 increasing with the softness, but even at a blue temper not more than 
 one half of the total carbon is so contained. The carbide, a black 
 amorphous substance, containing carbon 7 and iron 93 per cent., is 
 obtained in a slightly hydrated form when the steel is carefully acted 
 upon by a mixture of chromic and sulphuric acids, which dissolves iron 
 and oxidizes combined carbon, leaving the carbide comparatively un- 
 touched. A similar substance has been described by Dr. Miiller as 
 amorphous iron. It was obtained by acting on Bessemer steel with 
 diluted sulphuric acid. 
 
 " When iron cools from redness the loss of heat is proportional to 
 the lapse of time until a temperature of 700 to 800 C. is reached, 
 when the thermometer becomes stationary for a period varying from 
 26 to 70 seconds, according to the nature of the metal. This property, 
 originally described as recalescence by Mr. Barrett, has been studied 
 by Messrs. Osmond and Werth by means of the thermo-electric pile of 
 Lechatelier, who find that the recalescence is most marked in hard 
 and semi- hard steels, when it occurs at 655 to 675 C., while in elec- 
 trotype iron the retardation in cooling occurs at 855 C. This is con- 
 sidered in the latter case to be due to molecular transformation of the 
 metal, or from a to (3 iron, while the more marked change in the 
 former is attributed to the change of free or tempering carbon into 
 combined or annealing carbon, a reaction attended with a develop- 
 ment of heat. In white heat iron containing 4 per cent, of carbon 
 the effect of recalescence is considerably less than in hard steel with 
 1-25 per cent. This is due to the circumstance that the bulk of the 
 carbon is already combined with the iron, the annealing carbon being 
 at a minimum. The general conclusions arrived at by these ob- 
 servers are : 
 
 Carbon is present in two forms, namely 
 
 1. Annealing carbon, which predominates in steel cooled slowly 
 from a high temperature, exists as one or more definite carbonates 
 mechanically m> _! with the iron. 
 
 2. Hardening carbon, which is probably dissolved in (not combined 
 
512 METALLURGY OF IRON. 
 
 with) the iron, either alone or possibly combined with nitrogen and 
 hydrogen, and exists in a state of uniform diffusion in hardened 
 steel and white cast iron. 
 
 Annealing carbon is changed into hardening carbide by the disso- 
 ciation of the carbide at a red heat, and the reverse change is effected 
 by slow cooling. When, however, the cooling is sudden and the 
 amount of carbon high, a greater or less proportion of the latter 
 escapes conversion into carbide and retains the condition in which it 
 existed at the higher temperature. 
 
 3. Iron may exist in two molecular states, the first, or a, being soft 
 and malleable, and the second, (3, hard and brittle. The former cha- 
 racterizes all softened steel and pure iron, while the second is pro- 
 duced artificially by any mechanical pressure producing permanent 
 deformation, applied below a red heat, and also spontaneously at a 
 certain critical temperature as yet undetermined. The physical pro- 
 perties of any particular kind of iron, therefore, depend upon the 
 relative proportions of these four constituents, as well as of other 
 interposed foreign matters. 
 
 MANGANESE STEEL. 
 
 Manganese when added to mild steel between the limits 0-5 and I'O 
 per cent., adds to its tenacity while diminishing its ductility in a less 
 degree than is the case when the increased tenacity is obtained by 
 carbon. At 1 per cent, the metal becomes tender in forging, and a 
 further increase up to 2J per cent, renders it brittle and rotten, the 
 latter effect continuing, though in a diminishing degree, up to about 
 7 per cent. When, however, manganese is present between the limits 
 of 7J and 20 per cent, in steel containing from 0*8 to 1-2 per cent, of 
 carbon, it gives a metal combining high tensile strength (48 to 65 
 tons) with great hardness and extreme ductility. This remarkable 
 property has been discovered by Mr. E. A. Hadfield, who makes these 
 steels by the addition of high ferro -manganese to mild open hearth 
 steel. The method is not so well adapted for use with crucible steel, 
 as too much carbon is taken up if blacklead crucibles are used, and 
 ordinary clay crucibles are corroded into holes by the manganese at 
 the high temperature necessary for complete fusion. The necessity 
 of using ferro-manganese which contains 6 to 7 per cent, of carbon 
 renders it impossible to produce high manganese steel without a cor- 
 responding increase in the proportion of carbon, so that we are as 
 yet without knowledge as to the effect of manganese in large propor- 
 tions upon pure or low carburized iron. 
 
 High manganese steels, like those containing tungsten, are self* 
 
SUPPLEMENTARY NOTES. 513 
 
 hardening i.<?., become hard when allowed to cool slowly from a red 
 heat, while they are rendered tough and ductile when suddenly cooled 
 by quenching in water, oil, or sulphuric acid. Their extreme tough- 
 ness, however, renders them very difficult to work under cutting tools 
 in the lathe, boring, or drilling machine, so that they are best 
 suited for articles that can be fashioned for use by the hammer or 
 rolling-mill, or cast to pattern without requiring machining. Like 
 other high manganese and iron alloys, these steels are non-magnetic, 
 and in the form of wire have a very high electrical resistance. For 
 more detailed information on this subject the reader is referred to 
 Mr. Hadfield's original papers (Proceedings of the Institute of Civil 
 Engineers, Vol. xciii., pp. 1 61). 
 
 GrJEKS' SOAKING PlT. 
 
 Steel ingots may be brought to a proper heat for cogging or rolling 
 without the use of a reheating furnace by means of the soaking-pit 
 of Mr. John G-jers, which utilises the heat given out by the metal 
 during solidification. This is a square pit a little larger in every 
 dimension than the ingot, having a nine-inch fire-brick lining. As 
 soon as the ingot has sufficiently set to be safely handled, but before 
 it has completely solidified, it is lifted by a crane, deposited in the 
 pit, and closely covered, when the heat which under ordinary circum- 
 stances is dissipated in the atmosphere is stored up in the brickwork 
 lining, and suffices to bring the ingot to a proper heat for rolling in 
 about an hour. When the pit is cold, the surplus heat from two 
 ingots is sufficient to bring it up to a working temperature. When 
 it becomes too hot it may be cooled by dropping in a lump of bitumi- 
 nous coal. The surplus heat is then expended in the destructive distil- 
 lation of the coal. Besides the saving of fuel, the soaking-pit has the 
 important advantage of maintaining a neutral or reducing atmosphere 
 about the ingot, so that the surface oxidation is less than in an ordi- 
 nary heating furnace. By its use it is quite possible to convert iron 
 ore into steel rails with no other expenditure of fuel than the coke 
 employed in the blast furnace. Usually, however, it is found neces- 
 sary to reheat the cogged ingot before rolling it to the finished 
 section. 
 
 Mms IRON. 
 
 This term has been applied by Nordenfelt to a metal produced by 
 melting soft Swedish scrap iron in plumbago crucibles heated by the 
 flame of a mixture of heavy petroleum vapour and air, which gives a 
 much higher temperature than an ordinary coke melting-hole. The 
 
514 METALLURGY OF IRON. 
 
 furnace has three chambers, each containing two 66-lb. crucibles. 
 The melting is done in that nearest the fireplace, while the freshly 
 charged pots are heated in the other two by the spent flame. The 
 pots stand five or six rounds with full charges, as there is no line of 
 corrosion by slag as in ordinary steel melting. The charge is melted 
 in one and a -quarter hours ; the yield per six-pot furnace is 9^ to 12 
 cwts. of castings in twelve hours. The metal, although practically 
 free from carbon, gives perfectly sound castings by the addition of a 
 very small quantity (0-05 to O'lO per cent.) of aluminium. This is 
 said to lower the melting point from 160 to 280 degrees centigrade, so 
 that the metal is superheated when cast. Another explanation is 
 that the aluminium acts in a similar manner to phosphorus in bronze 
 and copper by reducing any dissolved oxide of iron without giving 
 rise to a gaseous product. For this purpose aluminium is said to be 
 more advantageous than manganese. Soft steel, with 0-08 per cent, 
 of carbon, when tempered with ferro-manganese so as to contain 0'70 
 per cent, of manganese, boiled violently in the mould, and gave 
 castings full of blow-holes ; while the same metal finished with 
 ferro-aluminium, and containing aluminium 0-064, silicon 0-024, and 
 manganese 0-010 percent., cast perfectly sound. 
 
 Mitis iron can be used for keys, hammers, chains, and other small 
 objects that are generally made of malleable cast iron. 
 
 NEWER FOKMS OF OPEN HEABTH FUKNACES. 
 
 Furnaces with round or elliptical hearths are now often used in 
 open hearth steel making. The former, or Batho's furnace, is a de- 
 velopment of that of Pernot, the movable inclined hearth being replaced 
 by a fixed horizontal one, which is carried upon iron girders and pillars, 
 leaving the underside exposed to the air. The regenerators, instead of 
 forming the substructure of the hearth, are entirely separated and con- 
 tained in independent circular towers resembling Cowper hot blast 
 stoves, and the gas and air passages are also separated from the fur- 
 nace proper, so that repairs can be effected without dismantling the 
 structure to the same extent as is necessary in the original Siemens 
 construction. In America an elliptical form, known as the Lash furnace, 
 is becoming popular. This has the regenerators placed in long hori- 
 zontal flues at right angles to the hearth with a central air flue parallel 
 to them, which draws air from under the hearth and so keeps it cool. 
 It has also steel plate skew backs inserted between the mouth of the 
 gas ports and the springing of the roof, which are kept cool by a current 
 of water. As at present constructed, these furnaces are worked by 
 natural gas, so that only one pair of regenerators for heating the air 
 
SUPPLEMENTARY NOTES. 515 
 
 is required. The depressed roof shown in Fig. 47 is now very often 
 replaced by a domed form, which, as shown by Mr. F. Siemens, 
 renders the furnace more efficient by giving room for the free develop- 
 ment of flame, the heating being done by radiation from the latter 
 and not by driving the gaseous current down upon the bath. Besides 
 giving a more perfect heat, this system is said to prevent the violent 
 cutting action of the flame upon the more exposed portions of the 
 brickwork. 
 
 The capacity of the open hearth furnace has been gradually increased 
 from 5 to 7 tons up to 15, 20, and even 40 tons, and in most in- 
 stances a saving of fuel has accompanied each increase in size. The 
 largest (40-ton) furnaces do not, however, seem to be quite as well 
 under control as those of 15 or 20 tons, which may therefore be con- 
 sidered as the mcst certain and economical in work. 
 
 The basic open hearth furnace has been applied with very consider- 
 able success to the manufacture of dead soft steel suitable for boiler 
 and ship plates, from pig iron containing a large proportion of phos- 
 phorus. At Brymbo, near Wrexham, mild steel of 24*5 tons ultimate 
 and 15 tons elastic resistance, with an elongation of 31 to 33 per cent, 
 upon an 8-inch test piece, is made from 4 parts of pig iron, containing 
 phosphorus, 3-0 ; carbon, 3'2 ; manganese, 1 '75 ; and silver, 0-4 per cent., 
 and part of wrought iron or steel scrap in the proportion of 4 to 1, in 
 Siemens' furnaces taking 12 to 20 ton charges. The hearth is made 
 of a 15 -inch layer of shrunk dolomite upon a fire-brick foundation, 
 and two inches of chromic iron ore are placed between the dolomite 
 in the siliceous brickwork. Sufficient limestone is added with the 
 charge to produce a basic slag from the outset, and additions of iron 
 ore and limestone are made at intervals during the progress of the 
 operation, which lasts about five hours, the quantity being regulated 
 by the appearance of fracture samples. The final tempering is done 
 with ferro-manganese, partly in the furnace and partly in the ladle, 
 10 to 12 Ibs. per ton being sufficient, while about 30 Ibs. are required 
 in the basic converter. The iron ore used is the black band of North 
 Staffordshire, containing about 1 per cent, of phosphorus, but as this 
 is fully oxidized, and in the presence of free lime, it passes into the 
 clay without in any way affecting the metal. The yield is 93 '5 per 
 cent, of the iron in the materials charged, and the consumption of fuel 
 11-07 cwts. per ton of ingots made. 
 
 In Hungary and Styria the use of the basic open hearth furnace has 
 been found advantageous even when dealing with pig iron low in 
 phosphorus, the steels produced being found to be sensibly freer from 
 phosphorus than that produced from the same materials upon a siliceous 
 lining. In most cases magnesia obtained from strongly calcined mag- 
 
516 METALLURGY OF IRON, 
 
 nesite is considered to be preferable to dolomite for the hearth 
 bottom, as it practically is indifferent to silica, and the use of isolating 
 layers of chromic iron ore is not necessary. Considerable time and 
 skill are required in making magnesia bottoms, but they are extremely 
 durable even with pig and ore charges which do not cut the basic 
 bottoms as badly as they do siliceous ones. The roof of the fiirnace 
 should be held in a bevelled ring forming a skew back, and supported 
 upon outer walls on the casing plates, so that its weight may be 
 entirely kept off the interior heated walls of the melting chamber. 
 Probably a better plan would be to construct the roof of magnesia 
 bricks, but this would add considerably to the cost. 
 
 Magnesite for furnace purposes is obtained from Eubcea, in the 
 Greek Archipelago, from Styria, Silesia, and Vigevano, in Lombardy. 
 
 Perhaps the best of all materials for the basic hearth is the so-called 
 neutral lining of chromic iron ore, which is almost indestructible. It 
 is very successfully applied at Clarence "Works, both to melting and 
 heating furnaces. 
 
 NEW DIRECT REDUCTION PROCESSES. 
 
 A new form of direct reduction process has been developed by Mr. 
 Husgavfel, in Finland, from the old Stiickofen or high-bloomary 
 furnace, which still survives in that country. 
 
 The new furnace is substantially the stiickofen rendered continuous 
 in working by means of a moveable hearth, and is similar in general 
 appearance to a small charcoal blast-furnace. It is 26 feet high, 5 
 feet broad at the boshes, and 4 feet at the throat. It is, however, 
 entirely constructed of iron, the stack being formed of two parallel 
 shells of boiler plate, which are kept apart by a plate wound about 
 them, forming a continuous spiral passage through which the blast 
 may be passed from above downwards. The lower part of the furnace 
 is a box of cast-iron plates fitted with trunnions, and two pairs of 
 water-cooled twyers at 3 and 6 inches respectively above the bottom, 
 which is mounted upon wheels, and when in use stands upon a plat- 
 form which is pressed up by a lever against the base ring of the stack. 
 The furnace is charged with charcoal and ore and worked in the 
 usual way, with the exception that the blast is heated by circulation 
 through the double casing of the stack, and so prevents adhesion of re- 
 duced iron. The reduced iron accumulates on the hearth, and a slag is 
 formed, which is tapped off from time to time. As the bloom increases 
 in size the blast nozzles are shifted from the lower to the upper rows 
 of twyers, and when the hearth is full it is lowered clear of the stack 
 and drawn by a chain up a pair of inclined guards, which receive the 
 
SUPPLEMENTARY NOTES. 517 
 
 trunnions and allow it to turn over, and drop the bloom into a "bogie 
 placed for its reception below. The product varies with the quality 
 of the ore, the burden on the furnace, and the temperature of the blast. 
 When very heavily burdened with blast at low temperature it is low in 
 carbon, (HO per cent., and phosphorus, but with lower burden and 
 hotter blast, iron with 1-2 per cent, of carbon may be obtained, with 
 a corresponding increase in the phosphorus reduced. The regulation 
 of the blast temperature is effected by varying the height of admission 
 into the jacket passages. If it is admitted at the top it traverses the 
 whole height of the stack, and becomes proportionately hotter than 
 when it goes in at one of the two lower ports. The production of this 
 furnace is from 2 to 3 tons of blooms per day, with a consumption of 
 204 bushels of charcoal per ton, as compared with 176 bushels which 
 are required to make a ton of pig iron from the same ores. The loss 
 of iron in the slags varies from about 18 per cent, when the blooms 
 are soft, to 7 per cent, when they are hard and steely, about two- 
 thirds of the phosphorus in the ore being eliminated in the former 
 case, while in the latter it is nearly all reduced. At "Wartsila, in 
 Finland, where the process was first unsuccessfully adopted, it is used 
 for making blooms from lake ores, which contain a considerable pro- 
 portion of phosphorus, and are afterwards converted into soft steel in 
 the basic open hearth furnace. 
 
 The Carbon Iron Company of Pittsburg has introduced a process for 
 making sponge iron blooms in an open hearth furnace from Lake 
 Superior hematite, using as a reducing material a compact anthracite 
 resembling graphite, which is veiy difficultly combustible. The ore 
 and coal ground are passed through a sieve of 16 meshes to an inch, 
 are mixed in the proportion of 4 to 1, and subjected to a low heat, at 
 most orange red, upon a bed of the same coal about 8 inches thick. 
 This heat is maintained by gas giving a strongly reducing atmosphere, 
 and air is carefully excluded. In about 1^- hours the charge is re- 
 duced, and can be made into balls like those from a puddling furnace, 
 which may be either shingled and rolled into puddled bars or taken 
 direct to the open hearth steel furnace. In the latter case, the heat 
 producing 1,550 Ibs. of sponge ball with 83 per cent, of iron, is finished 
 in 2J hours, but in the former 3 hours are necessary, as the balls 
 must be raised to a welding heat. The process has lately (May, 1889) 
 been modified by substituting coke, rendered difficultly combustible 
 by lime and fire-clay, for the graphitic anthracite. This material, 
 known as ' ' retarded coke, ' ' is made by covering coke crushed to a 
 16 -mesh with a wash of equal parts lime and fire-clay mixed in water 
 to the consistency of a thin cream, about 28 Ibs. of this mixture being 
 used per ton of coke. The operation is conducted in all other respects as 
 
518 METALLURGY OF IRON. 
 
 described above upon a hearth made of graphite. The average yield 
 from one ton of 65 per cent, ore is as follows : 
 
 Sponge for melting directly in open hearth furnace . 1,530 Ibs. 
 
 Squeezed sponge blown 1,160 
 
 Puddled ore, 3 by f inch 1,000 
 
 The loss of iron, taken over six months' working when using this 
 material in the open hearth furnace, is computed to be less than 13 per 
 cent, between the ore and the steel ingot. 
 
 WOBK OF AN AMEBICAN BLAST FUBNACE. 
 
 The F furnace of the Edgar Thompson Works, lighted on October 
 18th, 18S6, remained in blast for two years seven months and eight 
 days, when it was blown out, the lining having been worn beyond 
 the possibility of repair. During this time, which included seventy- 
 three days' stoppage on account of strikes, the total output amounted 
 to 224,795 tons of pig iron, or a daily average of 237 tons, the 
 maximum yield being : 
 
 In one day . 419 tons. 
 
 In one week 2,181 
 
 In one month 8,478 ,, 
 
 The average consumption of coke per ton of pig was 2,317 Ibs., or 
 20 cwts. 2 qrs. 21 Ibs. 
 
INDEX. 
 
 Abel on carbon in steel, 511. 
 
 Admiralty tests, 506. 
 
 Algerian iron ores, 96. 
 
 Allan's method of steel casting, 473. 
 
 Aluminium and iron, 52, 513. 
 
 Aluminous fluxes, analyses of, 148. 
 
 America, iron ores of, 99. 
 
 American blomnary process, 285. 
 
 American Bessemer works, 459. 
 
 Ammonia, production of, in blast 
 furnaces, 270. 
 
 Analyses of blackband ores, 86 ; of 
 carboniferous brown hematites, 
 71 ; of cast iron, 275, 276 ; of 
 clay iron ores, 84 ; of Cleveland 
 ores, 87 ; of magnetic ores, 61, 
 62 ; of spathic ores, 82. 
 
 Analysis of iron ores, method of, 
 116. 
 
 Anthracite furnaces of South Wales, 
 246 ; of United States, 249. 
 
 Antimony and iron, alloys of, 51. 
 
 Armour plates, methods of manu- 
 facture of, 382; compound, 475. 
 
 Arsenic and iron, compounds of, 34. 
 
 Assay of iron ores, dry, 104, 107 ; 
 wet, 110. 
 
 Bar iron, manufacture of, 368. 
 
 Barrow-in-Fumess, charges of fur- 
 naces at, 248. 
 
 Barrow hematite ores, analyses of, 
 69. 
 
 Basic- Bessemer process, 460. 
 
 Batho furnace, 514. 
 
 Bears of blast furnaces, 229. 
 
 Belgium, details of puddling fur- 
 naceo in, 332 ; dressing of iron 
 ores in, 124 ; yield of blast fur- 
 naces in, 249, 255. 
 
 Bell's refining process, 302. 
 
 Bergamask finery process, 310. 
 
 Berthier's assay of iron ore, 104. 
 
 Bessemer's process, 433 ; Jordan on 
 heat developed in, 448. 
 
 Bessemer steel, composition and 
 classification of, 446. 
 
 Bessemer slag test, 454. 
 
 Bicheroux's furnace, 400. 
 
 Bilbao, iron ores of, 94. 
 
 Blackband ironstones, analyses of, 
 86. 
 
 Blackband, method of roasting, 133. 
 
 Blake's rock breaker, loO. 
 
 Blast furnaces, temperature of, 269. 
 
 Blast, method of determining vo- 
 lume, 202. 
 
 Blast regulators, 184. 
 
 Blowing engine, construction and 
 details of, I 77. 
 
 Blowing in blast furnaces, 227. 
 
 Blowing out blast furnaces, 229. 
 
 Boetius's furnace, 401. 
 
 Bog and lake ores, analyses of, 79. 
 
 Boiling process of puddling, 316. 
 
 Boussingault's method of deter- 
 mining carbon, 483. 
 
 Brendon Hills, spathic ores of, 82. 
 
 Brescian steel process, 408. 
 
 Brown hematites, analyses of, 71, 76. 
 
 Bull-dog, 39. 
 
 Buttgenbach's furnace, 215. 
 
 Calder hot blast stove, 186. 
 Capacity and production of blast 
 
 furnaces, 230, 254. 
 Carbon and iron, compounds of, 40. 
 Carbon, determination of, in iron, 
 
 480. 
 
 Carbonate of protoxide of iron, 21. 
 Carinthian forge steel process, 407. 
 Carinthian gas puddling furnace, 
 
 332. 
 Carbon Iron Co.'s process, 517. 
 
520 
 
 INDEX. 
 
 Car on on carbon in iron, 42. 
 Case-hardening, methods of, 423. 
 Cast iron, analyses of, 275, 276. 
 Cast iron, classification of, 272. 
 Cast iron, composition of, 47. 
 Cast iron, grey and white, 41. 
 Cast steel, production of, 425. 
 Catalan forge process, 279. 
 Cementation, production of steel 
 
 by, 45. 
 
 Charging barrows, use of, 215. 
 Chemical changes in puddling, 328, 
 
 414. 
 
 Chenot's process, 283. 
 Chlorine and iron, 37. 
 Chromium, alloy of, with iron, 52. 
 Clay ironstone, analyses of, 84. 
 Clay ironstone, roasting in clamps, 
 
 132. 
 Cleveland, details of blast f urnaces 
 
 in, 246, 507. 
 
 Cleveland, iron ores of, 86. 
 Cleveland ironstone, analyses of, 87. 
 Coal measures, clay iron ores of, 82. 
 Cobalt, alloy of, with iron, 52. 
 Copper, action of, on iron, 49. 
 Cornwall ore bank, 101. 
 Cowper's stove, 192, 199. 
 Cup and cone, 218. 
 
 Bank's puddling furnace, 339. 
 
 Descent of charges in blast fur- 
 naces, time of, 231. 
 
 Desulphurising ores by steam, 144. 
 
 Dry assay of iron ore, 104. 
 
 Dudley's rail formula, 504. 
 
 Dudley's phosphorus units, 504. 
 
 Dust of gas flues, composition of, 
 271. 
 
 Eastwood's mechanical puddler,336. 
 Eggertz's method of analysing iron, 
 
 487, 488, 490. 
 Eisenerz, crusher at, 129. 
 Eisenerz, spathic ores of, 82. 
 Elba, specular iron of, 71, 244. 
 Electrotype iron, Jacobi's process, 
 
 14. 
 
 Ellerhausen's process, 837. 
 Eston steel works, 463. 
 
 Ferric acid, 27 
 Ferro-manganese, 253. 
 Ferro-silicon, 39, 49. 
 
 Fettling, materials used for, 321. 
 Fluid compression of steel, 473. 
 Ford's determination of manganese, 
 
 495. 
 
 Forest of Dean,bro wn iron ores of, 7 . 
 Forge and mill cinder, use of, 148. 
 Form of blast furnaces, 217. 
 Foundation of forge hammers, 351. 
 Franche-Comte finery process, 310, 
 
 313. 
 
 Franklinite, 27, 54. 
 Fremy on nitrogen in steel, 46. 
 
 Gaillard's furnace, 400. 
 Gas-collecting apparatus for blast 
 
 furnaces, 211. 
 Gas-heated stoves, 192. 
 Gas-producer, Siemens', 271. 
 Gas puddling furnace, 317- 
 Gases of blast furnace, composition 
 
 of, 271. 
 Gases of Bessemer converter, Sne- 
 
 lus on, 509. 
 
 Gellivara, magnetic iron ores of, 61. 
 German steel tests, 505. 
 Gjers on Cleveland furnaces, 508. 
 Gjers's calcining kiln, 137. 
 Gjers's pneumatic lift, 176. 
 Gjers's soaking pit, 513. 
 Glazy pig iron, 49. 
 Gold and iron, alloy of, 51. 
 Graphitic and combined carbon in 
 
 iron, 41. 
 Graphitic carbon, determination of, 
 
 465. 
 
 Gruner on Heaton's process, 299. 
 Gurlt's method of making wrought 
 
 iron, 284. 
 
 Hadfield's steel, 512. 
 
 Hardening and tempering steel, 478. 
 
 Harz, weathering of ores in, 126. 
 
 Has well' s hydraulic hammer, 3GO. 
 
 Hearth of blast furnace, construc- 
 tion of, 168. 
 
 Heat, consumption of, in blast fur-, 
 nace operations, 258. 
 
 Heaton's process, 297. 
 
 Helves, varieties of, 350. 
 
 Hematite, brown, 56 
 
 Hematite, red, 54. 
 
 Hematite, red, in Lancashire and 
 Cumberland, 67, 248. 
 
 Henderson's process, 300. 
 
INDEX. 
 
 521 
 
 Hoi ley' s converter, 457. 
 Hollow fire, (South Wales, 313. 
 Horse-shoe pipe-stove, 186. 
 Hot blast, determination of tem- 
 perature of, 269. 
 
 Hot blast stoves or ovens, 186, 208. 
 Hot blast twyers, details of, 209. 
 Huronian iron ores, 65, 100. 
 Husgavfel process, 516. 
 Hydrates of oxides of iron, 20. 
 Hydrates of peroxide of iron, 24. 
 Hydraulic forging press, 476. 
 
 Ilm.enite, or titanic iron ore, 55. 
 
 India, iron ores of, 98. 
 
 Indian methods of making wrought 
 iron, 285. 
 
 Iron, physical and chemical pro- 
 perties of, 13, 494. 
 
 Iron pyrites, 36. 
 
 Jones's method of steel cast ing, 474. 
 
 Karsten's table of compounds of 
 
 iron and carbon, 41. 
 Kilns, roasting, for iron ores, 135. 
 Kirkaldy's experiments, 497. 
 Kirkless Hall, blast furnace at, 248. 
 Krupp steel compression, 475. 
 Krupp refining process, 302. 
 
 Lake Superior blast furnaces, 
 charges and yields of, 240. 
 
 Lancashire, furnaces smelting 
 hematite, 248. 
 
 Lancashire hearth, used in Sweden, 
 310, 313. 
 
 Lang's treatment of cinders, 151. 
 
 Langen's gas apparatus, 214. 
 
 Lash furnace, 514. 
 
 Laurentian iron ores, 100. 
 
 Lead from blast furnaces, 272. 
 
 Lenz on electrotype iron, 15. 
 
 Lever hammers, varieties of, 350. 
 
 Lifts for blast furnaces, construc- 
 tion of, 174. 
 
 Lignite, puddling with, in Styria, 
 333. 
 
 Limestones, analyses of, 147. 
 
 Lloyd's tests, 507. 
 
 Low Moor, puddling process at, 331. 
 
 Lundin's gas furnace, 382. 
 
 Lurman's slag twyer, 171. 
 
 Luxemburg, ores of, 93. 
 
 Magnetic iron ores, analyses of, 61, 
 
 62. 
 
 Magnetic oxide of iron, 25, 53. 
 Magnetic pyrites, 36. 
 Magnetism of iron, 16. 
 Magnoferrite, 23, 27. 
 Malleable cast iron, 402. 
 Manganese steel, Hadfield's, 512. 
 Marguerite's wet assay, 111. 
 Martial regulus, 51. 
 Martite, 23. 
 
 Mechanical puddling, 335. 
 Melting points of metals, 204. 
 Meteoric iron, nickel in, 51. 
 Minary and Soudry's treatment of 
 
 cinders, 151. 
 Mitis iron, 513. 
 Mixture and descent of charges in 
 
 blast furnaces, 223. 
 Mokta el Hadid, 96. 
 Muller on gases in steel, 474. 
 Miisen, spathic ores of, 82. 
 Mushet's cast steel process, 431. 
 
 Nassau, red iron ores of, 72. 
 Natural or forge steel processes, 404. 
 Neutral lining, 516. 
 Nitrogen and iron, 28. 
 Nordenfelt's process, 513. 
 
 Obuchow's cast steel process, 403. 
 Open-hearth steel processes, 466. 
 Open-topped furnaces, methods of 
 
 collecting gas from, 211. 
 Oxides of iron, 19. 
 
 Parry on gases in steel, 474. 
 
 Parry's method of puddling, 338. 
 
 Parry's method of refining, 296. 
 
 Passivity of iron, 17. 
 
 Pattinsori's determination, of man- 
 ganese, 494. 
 
 Peat, puddling with, in St) ? ria, 333. 
 
 Penny's method of wet assay, 111. 
 
 Peinot furnace, 470. 
 
 Phosphate of iron vivianite, 32. 
 
 Phosphides of iron, Percy and 
 Freese on, 30. 
 
 Phosphorus, action of, on iron, 33. 
 
 Phosphorus in iron, determination 
 of, 485. 
 
 Phosphorus in iron ores, 33. 
 
 Phosphorus, removal of, in pud- 
 dling, 329 ; in steel, 461, 472. 
 
522 
 
 INDEX. 
 
 Phosphorus steel, 500. 
 
 Pig washing process, 302. 
 
 Piles for merchant iron, details of, 
 
 375. 
 Pisolitic ores dressed by jigging, 
 
 124. 
 
 Pistol pipe-stove, 188. 
 Plate and sheet iron, manufacture 
 
 of, 379. 
 
 Platinum and steel alloy, 52. 
 Plattner's fluxes for iron assaying, 
 
 107. 
 
 Pneumatic lift, 176. 
 Position of hot "blast stoves, 208. 
 Ponsard's furnace, 398. 
 Ponsard's forno-aonvertisseur, 472. 
 Pouillet's pyrometric method, 205. 
 Pressure gauges, 201. 
 Price and Nicholson's cast steel 
 
 process, 404. 
 
 Protosulphide of iron, 35. 
 Protoxide of iron, 19. 
 Puddled iron, qualities of, 327. 
 Puddling furnace, construction of, 
 
 316 
 
 Puddling, methods of, 322. 
 Pure iron, Matthieson's method of 
 
 producing, 14. 
 Purple ore, analysis of, 509. 
 Pyrometers for hot blast, 204. 
 Pyrometric alloys, melting points 
 
 of, 205. 
 
 Eachette's blast furnace, 222. 
 Kail rolling mill, 366. 
 Rails, details of manufacture, 377. 
 Eamsbottom's duplex hammer, 357. 
 Red iron ores, analyses of, 68. 
 Refinery, details of, - 290. 
 Reheating furnace, details of, 373. 
 Rolling mills, details of, 361. 
 Rouge, methods of production of, 22. 
 Round and oval ovens, 188. 
 
 Sandberg's rail test, 504. 
 
 Scale oxide, 20. 
 
 Schafhautl's powder used in pud- 
 dling, 330. 
 
 Scotland, blackband iron ores of, 85. 
 
 Scotland, working details of blast 
 furnace in, 248. 
 
 Secondary formations, "brown iron 
 ores of, 75. 
 
 Secondary o^iis of England, Judd 
 on, 88. 
 
 Sections of blast furnaces, 232. 
 
 Shears, cropping, varieties of, 371. 
 
 Siderite, 57. 
 
 Siegen blast furnaces, charges and 
 yields of, 236. 
 
 Siegen forge steel process, 408. 
 
 Siegen, kilns used in, 139. 
 
 Siemens' cast steel furnace, 430. 
 
 Siemens' gas producer and furnaces, 
 387, 401. 
 
 Siemens' pyrometers, 206. 
 
 Siemens' furnace, Krans on the, 394. 
 
 Siemens' rotatory furnace, 346. 
 
 Siemens' ore process* 477- 
 
 Siemens-Martin process, 466. 
 
 Silesian gas refinery, 295. 
 
 Silicate of protoxide of iron, 39. 
 
 Silicates, fusibility of, 153, 
 
 Silicon, elimination of, in Bessemer 
 process, 451. 
 
 Silicon, Eggertz's method of deter- 
 mining, 490. 
 
 Silicon and iron, compounds of, 38. 
 
 Silver and iron, 51. 
 
 Slags, blast furnace, composition of. 
 154. 
 
 Slags, blast furnace, physical cha- 
 racter of, 157. 
 
 Slags of blast furnace, method of 
 removing, 170. 
 
 Slags of puddling furnaces, compo- 
 sition of, 327, 329, 416. 
 
 Slags of the Bessemer process, com- 
 position of, 447 j basic, 464. 
 
 Slide-blowing engines, 178. 
 
 Snelus's dephosphorising process, 
 461. 
 
 Snelus on graphite and silicon in 
 cast iron, 48. 
 
 Snelus on Beaton's process, 300. 
 
 Snelus on the Bessemer process, 451. 
 
 South Staffordshire blast furnaces, 
 charges and yields of, 243. 
 
 South Staffordshire, consumption 
 of iron ores in, 242. 
 
 South Wales, calcining kilns used 
 in, 136. 
 
 South "Wales, charges and yields of 
 blast furnaces in, 245. 
 
 South Wales, finery process, 311. 
 
 Spanish iron ore?, 94. 
 
INDEX. 
 
 523 
 
 Spathic, iron ore, analyses of, 82. 
 Special methods of determining 
 
 manganese, 494. 
 Specific gravities of iron and steel, 
 
 447, 478. 
 Spectroscope, use of, in Bessemer 
 
 process, 452. 
 
 Specular iron ore, volcanic, 22. 
 Specular schist of Lake Superior, 240 
 Speiss, arsenides of iron, 34. 
 Spencer's rotatory puddling fur- 
 nace, 345. 
 
 Spiegeleisen, views on its composi- 
 tion, 42. 
 Spiegeleisen, production of, in 
 
 Siegen, 22 ; at Marseilles, 253. 
 Spiegeleisen, production of, at 
 
 Newark, N. J., 251. 
 Spiral stove, 179. 
 Squeezers, varieties of, 359. 
 Stacks, blast furnace, construction 
 
 of, 164. 
 
 Steam hammers, varieties of, 353. 
 Steel puddling, method of, 409. 
 Stolberg, dressing of iron ores at, 123. 
 Stoppage of blast furnaces, 229. 
 Strength of cast iron and steel, 493. 
 Styffe's experiments, 498. 
 Styria, spathic iron ores of, 82. 
 Styrian blast furnaces, charges and 
 
 yields of, 234. 
 
 Styrian forge steel process, 405. 
 Styrian kiln for pyritic ores, 142. 
 Sulphate of protoxide of iron, 37. 
 Sulphur, action of, on cast iron, 45. 
 Sulphur and iron, compounds of, 35. 
 Sulphur, determination of, in iron 
 
 ores, 485. 
 
 Surface of heating stoves, 201. 
 Swedish blast furnaces, charges and 
 
 yields of, 238. 
 
 Swedish finery process, 313. 
 Swedish gas calcining kiln, 140. 
 Swedish method of assay, 108. 
 Swedish method of charging blast 
 
 furnaces, 226. 
 Swedish method of collecting gases, 
 
 211. 
 
 Tafna, ores of, 97. 
 Tapping operation of 'blast fur- 
 naces, 227. 
 Terre-Noire steel experiments, 499. 
 
 Tests for wrought iron, 499. 
 
 Thomas and Laurent's stove, 191. 
 
 Thomas and Gilchrist'sprecess,462. 
 
 Thomas and Gilchrist's process, 
 Jordan on, 464. 
 
 Tilt-hammer, Swedish, for crush- 
 ing, 129. 
 
 Tin and iron, alloys of, 50. 
 
 Titaniferous iron sands, 72. 
 
 Titanium, action of, on iron, 53. 
 
 Traversella, magnetic ores of, 63. 
 
 Tungsten, action of, on iron and 
 steel, 52. 
 
 Twyers, arrangement of, 208. 
 
 Uchatius' cast steel process, 403. 
 United States, yield of blast fur- 
 naces in, 249, 255. 
 Universal rolling mills, 367. 
 Unlined crucibles, assay in, 107. 
 
 Valves for blast engines, forms of, 
 
 177. 
 Vanadium and iron, 53. 
 
 Walker's converter, 458. 
 
 Walloon finery process, 313. 
 
 Wartsila, bloomary at, 517. 
 
 Washing process, Krupp's, 302. 
 
 Wasseralfingen stove, 190. 
 
 Waste gases of blast furnaces, com- 
 position of, 267. 
 
 Waste heat of mill furnaces, utili- 
 sation of, 384. 
 
 Water balance lift, 175. 
 
 Water twyer, 210. 
 
 Water tymp, 169. 
 
 Weardale, spathic ores of, 82. 
 
 Weisbach's formula for calculating 
 hot blast, 202. 
 
 Westphalia, roasting pyritic ores 
 in, 133. 
 
 Whitwell's stove, 194, 200. 
 
 Whitworth's steel-casting, 474. 
 
 William's determination of man- 
 ganese, 495. 
 
 Wootz, method of making, 404. 
 
 Yields of puddled iron, 330. 
 Yields of Bessemer works, 459. 
 
 Zinc, action of, on iron, 49. 
 Zinc oxide deposited in blast fur- 
 naces, 271. 
 
ON 
 
 MINING, METALLURGY, & 
 
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 BRITISH MINING 
 
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 FUTURE PROSPECTS OF 
 
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 LATE KEEPER OF MINING RECORDS ; 
 
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 With Draughting, and the Centre of Effort of the Sails. By ROBERT 
 KIPPING, N.A .... . 2/6 
 
 Marine Engines and Steam Vessels. 
 
 By R. MURRAY, C.E. Eighth Edition, thoroughly revised, with Addi- 
 tions by the Author and by GEORGE CARLISLE. C.E. . . . 4/6 
 
 Iron Ship-Building. 
 
 With Practical Examples. By JOHN GRANTHAM. Fifth Edition . 4/Q 
 
 Naval Architecture : 
 
 An Exposition of Elementary Principles. By JAMES PEAKE . . 3/6 
 
 Ships for Ocean and River Service, 
 
 Principles of the Construction of. By HAKON A. SOMMERFELDT . 1 /Q 
 
 Atlas of Engravings 
 
 To Illustrate the above. Twelve large folding Plates. Royal 4to, cloth 7/6 
 
 The Forms of Ships and Boats. 
 
 By W. BLAND. Seventh Edition, revised, with numerous Illustrations and 
 Models 1/6 
 
6 WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 
 
 ARCHITECTURE AND THE 
 
 BUILDING ARTS. 
 Constructional Iron and Steel Work, 
 
 As applied to Public, Private, and Domestic Buildings. By FKANCIS 
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 Building Estates : 
 
 A Treatise on the Development, Sale, Purchase, and Management of Build- 
 ing Land. By F. MAITLAND. Second Edition, revised . . 2/0 
 
 The Science of Building : 
 
 An Elementary Treatise on the Principles of Construction. By E. WYND- 
 HAM TARN, M.A. Lond. Third Edition, revised and enlarged . 3/6 
 
 The Art of Building : 
 
 General Principles of Construction, Strength, and Use of Materials, Working 
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 A Book on Building, 
 
 Civil and Ecclesiastical. By Sir EDMUND BECKETT, Q.C. (Lord GRIM- 
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 Dwelling-Houses (The Erection of), 
 
 Illustrated bya Perspective View, Plans, and Sections of a Pair of Villas, with 
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 Cottage Building. 
 
 By C. BRUCK ALLEN. Eleventh Edition, with Chapter on Economic Cot- 
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 Acoustics in Relation to Architecture and Building : 
 
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 The Rudiments of Practical Bricklaying. 
 
 General Principles of Bricklaying ; Arch Drawing, Cutting, and Setting ; 
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 Brickwork : 
 
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 Rudimentary Treatise on the Manufacture of; containing an Outline of the 
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 Carpentry and Joinery Atlas 
 
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WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 7 
 A Practical Treatise on Handrailing ; 
 
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 Practical Lessons in the Framing of Wood Roofs. For the Use of Working 
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 By WYVILL J. CHRISTY, Architect. With 160 Woodcuts . . 3/Q 
 
 Shoring 
 
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 The Timber Importer's, Timber Merchant's, and 
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 By R. E. GRANDY 2/O 
 
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 Warming and Ventilation 
 
 Of Domestic and Public Buildings, Mines, Lighthouses, Ships, &c. By 
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 Portland Cement for Users. 
 
 By HENRY FAIJA, A.M. Inst. C.E. Third Edition, Corrected . 2/O 
 
 Limes, Cements, Mortars, Concretes, Mastics, Plas- 
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 By G. R. BURNBLL. C.E. Thirteenth Edition . . . .1/6 
 
8 WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 
 
 Masonry and Stone-Cutting. 
 
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 Experimental Essays on the Principles of Construction. By W. BLAND. 
 
 1 6 
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 In Bricklayers', Masons', Plasterers', Plumbers', Painters', Paperhangers', 
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 of Architecture, Engineering, and other Applied Sciences. By E. WYND- 
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 Hints to Young Architects. 
 
 By GEORGE WIGHTWICK, Architect. Fifth Edition, revised and enlarged 
 by G. HUSKISSON GUILLAUME, Architect ...... 3/6 
 
 Architecture Orders : 
 
 The Orders and their ^Esthetic Principles. By W. H. LEEDS. Illustrated. 
 
 1/6 
 Architecture Styles : 
 
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 F.R.I.B.A. Illustrated ......... 2/O 
 
 %* ORDERS AND STYLES OF ARCHITECTURE, in One Vol., 3*. 6d. 
 
 Architecture Design : 
 
 The Principles of Design in Architecture, as deducible from Nature and 
 exemplified in the Works of the Greek and Gothic Architects. By EDW. 
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 %* The three preceding Works in One handsome Vol., half bound, entitled 
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 Perspective for Beginners. 
 
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 By GEORGE PYNE . '. . . , . . . 2/0 
 
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 By T. A. RICHARDSON. With Illustrations, engraved by O. JEWITT 1 /6 
 
 Glass Staining, and the Art of Painting on Glass. 
 
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 an Appendix on THE ART OF ENAMELLING ..... 2/6 
 
 Yitruvius The Architecture of. 
 
 In Ten Books. Translated from the Latin by JOSEPH GWILT, F.S.A., 
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 N.B. This is the only Edition <?/"ViTRUVlus procurable at a moderate price. 
 
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WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 
 
 INDUSTRIAL AND USEFUL ARTS. 
 Cements, Pastes, Glues, and Gums. 
 
 A Practical Guide to the Manufacture and Application of the various 
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 upwards of 900 Recipes and Formulae. By H. C. STANDAGE . . 2/O 
 
 Clocks and Watches, and Bells, 
 
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 Practical Organ Building. 
 
 By W. E. DICKSON, M.A. Second Edition, Revised, with Additions 2/6 
 
 Coach-Building : 
 
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 W. GRAHAM 2/O 
 
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 A Practical Handbook for Tinsmiths, Coppersmiths, Zincwprkers, &c., with 
 46 Diagrams. By W. J. E. CRANE. Second Edition, revised . 1 /6 
 
 Sewing Machinery: 
 
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 ing, &c. By J. W. URQUHART, C.E 2/0 
 
 Gas Fitting: 
 
 A Practical Handbook. By JOHN BLACK, Second Edition, Enlarged. 
 With 130 Illustrations 2/6 
 
 Construction of Door Locks. 
 
 From the Papers of A. C. HOBBS. Edited by CHARLES TOMLINSON, F.R.S. 
 With a Note upon IRON SAFES by ROBERT MALLET. Illustrated . 2/6 
 
 The Model Locomotive Engineer, Fireman, and 
 Engine-Boy. 
 
 Comprising an Historical Notice of the Pioneer Locomotive Engines and 
 their Inventors. By MICHAEL REYNOLDS. Second Edition. With 
 numerous Illustrations, and Portrait of George Stephenson . . 3/6 
 
 The Art of Letter Painting made Easy. 
 
 ByJ. G. BADENOCH. With 12 full-page Engravings of Examples . 1/6 
 
 The Art of Boot and Shoemaking. 
 
 Including Measurement, Last-fitting, Cutting-out, Closing and Making. By 
 JOHN BEDFORD LENO. With numerous Illustrations. Third Edition 2/0 
 
 Mechanical Dentistry: 
 
 A Practical Treatise on the Construction of the Various Kinds of Artificial 
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 Wood Engraving: 
 
 A Practical and Easy Introduction to the Art. By W. N. BROWN . 1 /6 
 
 Laundry Management. 
 
 A Handbook for Use in Private and Public Laundries. Including Accounts 
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10 WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 
 
 AGRICULTURE, GARDENING, ETC. 
 Draining and Embanking : 
 
 A Practical Treatise. By Prof. JOHN SCOTT. With 68 Illustrations 1 /Q 
 
 Irrigation and Water Supply: 
 
 A Practical Treatise on Water Meadows, Sewage Irrigation, Warping, &c. ; 
 on the Construction of Wells, Ponds, Reservoirs, &c. By Prof. JOHN 
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 Farm Roads, Fences, and Gates: 
 
 A Practical Treatise on the Roads, Tramways, and Waterways of the 
 Farm; the Principles of Enclosures; and the different kinds of Fence, 
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 Farm Buildings : 
 
 A Practical Treatise on the Buildings necessary for various kinds of Farms, 
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 Barn Implements and Machines : 
 
 Treating of the Application of Power and Machines used in the Threshing- 
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 2/0 
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 With Principles and Details of Construction and Points of Excellence, their 
 Management, &c. By Prof. JOHN SCOTT. With 138 Illustrations 2/0 
 
 Agricultural Surveying : 
 
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 for Valuing Estates. By Prof. J. SCOTT. With 62 Illustrations . 1 /Q 
 
 A Treatise on Land Surveying, Levelling, and Setting-out ; with Directions 
 rof. 
 
 Farm Engineering. 
 
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 1,150 pages, and over 600 Illustrations. Half-bound . . . 12/0 
 
 Outlines of Farm Management. 
 
 Treating of the General Work of the Farm ; Stock ; Contract Work ; 
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 ** The above Two Vols. in One, handsomely half-bound, price Qs. 
 
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WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 11 
 
 Book-keeping for Farmers and state Owners. 
 
 A Practical Treatise, presenting, in Three Plans, a System adapted for all 
 classes of Farms. By J. M. WOODMAN. Third Edition, revised . 2/6 
 
 Ready Reckoner for the Admeasurement of Land. 
 
 By A. ARMAN. Third Edition, revised and extended by C. NORRIS 2/0 
 
 Miller's, Corn Merchant's, and Farmer's Ready 
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 Second Edition, revised, with a Price List of Modern Flour Mill Machinery, 
 byW. S. HUTTON, C.E 2/0 
 
 The Hay and Straw Measurer. 
 
 New Tables for the Use of Auctioneers, Valuers, Farmers, Hay and Straw 
 Dealers, &c. By JOHN STKELE 2/0 
 
 Meat Production. 
 
 A Manual for Producers, Distributors, and Consumers of Butchers' Meat. 
 By JOHN EWART 2/6 
 
 Sheep : 
 
 The History, Structure, Economy, and Diseases of. By W. C. SPOONER, 
 M.R.V.S. Fifth Edition, with fine Engravings 3/6 
 
 Market and Kitchen Gardening. 
 
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 Kitchen Gardening Made Easy. 
 
 Showing the best means of Cultivating every known Vegetable and Herb, 
 &c., with directions for management all the year round. By GEORGE M. F. 
 GLENNY. Illustrated 1/6 
 
 Cottage Gardening: 
 
 Or Flowers, Fruits, and Vegetables for Small Gardens. By E. HOBDAY. 
 
 1/6 
 Garden Receipts. 
 
 Edited by CHARLES W. Qum .1/6 
 
 Fruit Trees, 
 
 The Scientific and Profitable Culture of. From the French of M. Du 
 BREUIL. Fourth Edition, carefully Revised by GEORGE GLENNY. With 
 187 Woodcuts 3/6 
 
 The Tree Planter and Plant Propagator : 
 
 With numerous Illustrations of Grafting, Layering, Budding, Implements, 
 Houses, Pits, &c. By SAMUEL WOOD 2/0 
 
 The Tree Pruner : 
 
 A Practical Manual on the Pruning of Fruit Trees. Shrubs, Climbers, and 
 Flowering Plants. With numerous Illustrations. By SAMUEL WOOD 1/6 
 
 *** The above Tiuo Vols. in One, handsomely half-bound, price Qs. QJ. 
 
 The Art of Grafting and Budding. 
 
 By CHARLES BALTET. With Illustrations 2/6 
 
12 WE ALE'S SCIENTIFIC AND TECHNICAL SERIES. 
 
 MATHEMATICS, ARITHMETIC, ETC. 
 Descriptive Geometry, 
 
 An Elementary Treatise on ; with a Theory of Shadows and of Perspective, 
 extracted from the French of G. MONGE. To which is added a Description 
 of the Principles and Practice of Isometrical Projection. By J. F. HEATHER, 
 M.A. With 14 Plates . . . 2/0 
 
 Practical Plane Geometry: 
 
 Giving the Simplest Modes of Constructing Figures contained in one Plane 
 and Geometrical Construction of the Ground. By J. F. HEATHER, M.A. 
 With 215 Woodcuts 2/0 
 
 Analytical Geometry and Conic Sections, 
 
 A Rudimentary Treatise on. By JAMES HANN. A New Edition, re- 
 written and enlarged by Professor J. R. YOUNG .... 2/0 
 
 Euclid (The Elements of). 
 
 With many Additional Propositions and Explanatory Notes ; to which is 
 prefixed an Introductory Essay on Logic. By HENRY LAW, C.E. . 2/6 
 
 \* Sold also separately, -viz : 
 
 Euclid. The First Three Books. By HENRY LAW, C.E. . . .1/6 
 Euclid. Books 4, 5, 6, ii, 12. By HENRY LAW, C.E. . . .1/6 
 
 Plane Trigonometry, 
 
 The Elements of. By JAMES HANN. 1 /g 
 
 Spherical Trigonometry, 
 
 The Elements of. By JAMES HANN. Revised by CHARLES H. DOW- 
 LING, C.E 1/0 
 
 ** Or with " The Elements of Plane Trigonometry," in One Volume, zs. 60". 
 
 Differential Calculus, 
 
 Elements of the. By W. S. B. WooLHOUSE, F.R.A.S., &c. . .1/6 
 
 Integral Calculus. 
 
 By HOMERSHAM Cox, B.A. 1/Q 
 
 Algebra, 
 
 The Elements of. By JAMES HADDON, M.A. With Appendix, containing 
 Miscellaneous Investigations, and a Collection of Problems . . 2/6 
 
 A Key and Companion to the Above. 
 
 An extensive Repository of Solved Examples and Problems in Algebra 
 By J. R. YOUNG 1/6 
 
 Commercial Book-keeping. 
 
 With Commercial Phrases and Forms in English, French, Italian, and 
 German. By JAMES HALDON, M.A 1/6 
 
 Arithmetic, 
 
 A Rudimentary Treatise on. With full Explanations of its Theoretical 
 Principles, and numerous Examples for Practice. For the Use of Schools 
 and for Self-Instruction. By J. R. YOUNG, late Professor of Mathematics 
 in Belfast College. Eleventh Edition ... . . 1 /6 
 
 A Key to the Above. 
 
 By J. R. YOUNG .... . . . 1 /6 
 
 Equational Arithmetic, 
 
 Applied to Questions of Interest, Annuities, Life Assurance, and General 
 Commerce ; with various Tables by which all Calculations may be greatly 
 facilitated. By W. HIPSLEY . 1 /6 
 
 Arithmetic, 
 
 Rudimentary, for the Use of Schools and Self-Instruction. By JAMES 
 HADDON, M.A. Revised by ABRAHAM ARMAN . . . .1/6 
 
 A Key to the Above. 
 
 By A. ARMAN 1/6 
 
WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 13 
 
 Mathematical Instruments : 
 
 Their Construction, Adjustment, Testing, and Use concisely Explained. 
 By J. F. HEATHEK, M.A., of the Royal Military Academy, Woolwich. 
 Fourteenth Edition, Revised, with Additions, by A. T. WALMISLEY, 
 M.I.C.E. Original Edition, in i vol., Illustrated .... 2/0 
 
 %* In ordering the above, be careful to say " Original Edition" or give the 
 number in the Series (32), to distinguish it from the Enlarged Edition in 
 3 vols. (as follows) 
 
 Drawing and Measuring Instruments. 
 
 Including I. Instruments employed in Geometrical and Mechanical Draw- 
 ing, and in the Construction, Copying, and Measurement of Maps and 
 Plans. II. Instruments used for the purposes of Accurate Measurement, 
 and for Arithmetical Computations. By J. F. HEATHER, M.A. . 1 /Q 
 
 Optical Instruments. 
 
 Including (more especially) Telescopes, Microscopes, and Apparatus for 
 
 Seducing copies of Maps and Pians by Photography. By J. F. HEATHER, 
 .A. Illustrated 1/6 
 
 Surveying and Astronomical Instruments. 
 
 Including I. Instruments used for Determining the Geometrical Features 
 of a portion of Ground. II. Instruments employed in Astronomical Ob- 
 servations. By J. F. HEATHER, M.A. Illustrated. . . .1/6 
 
 *** The above three -volumes form an enlargement of the Authors original work, 
 " Mathematical Instruments," price zs. (Described at top of page.) 
 
 Mathematical Instruments : 
 
 Their Construction, Adjustment, Testing and Use. Comprising Drawing, 
 Measuring, Optical, Surveying, and Astronomical Instruments. By J. F. 
 HEATHER, M.A. Enlarged Edition, for the most part entirely re-written. 
 The Three Parts as above, in One thick Volume. .... 4/6 
 
 The Slide Rule, and How to Use It. 
 
 Containing full, easy, and simple Instructions to perform all Business Cal- 
 culations with unexampled rapidity and accuracy. By CHARLES HOARE, 
 C.E. With a Slide Rule, in tuck of cover. Fifth Edition. . . 2/6 
 
 Logarithms. 
 
 With Mathematical Tables for Trigonometrical, Astronomical, and Nautical 
 Calculations. By HENRY LAW, C.E. Revised Edition . . . 3/0 
 
 Compound Interest and Annuities (Theory of). 
 
 With Tables of Logarithms for the more Difficult Computations of Interest, 
 Discount, Annuities, &c., in all their Applications and Uses for Mercantile 
 and State Purposes. By FEDOR THOMAN, Paris. Fourth Edition . 4-/Q 
 
 Mathematical Tables, 
 
 For Trigonometrical, Astronomical, and Nautical Calculations ; to which is 
 prefixed a Treatise on Logarithms. By H. LAW, C.E. Together with a 
 Series of Tables for Navigation and Nautical Astronomy. By Professor J. 
 R. YOUNG. New Edition 4/0 
 
 Mathematics, 
 
 As applied to the Constructive Arts. By FRANCIS CAMPIN, C.E., &c. 
 Second Edition 3/0 
 
 Astronomy. 
 
 By the late Rev. ROBERT MAIN, F.R.S. Third Edition, revised and cor- 
 rected to the Present Time. By W. T. LYNN, F.R.A.S. . . . 2/0 
 
 Statics and Dynamics. 
 
 The Principles and Practice of. Embracing also a clear development of 
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14 WE ALE'S SCIENTIFIC AND TECHNICAL SERIES. 
 
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 A Dictionary of Painters, and Handbook for Picture 
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 Being a Guide for Visitors to Public and Private Picture Galleries, and for 
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 Painting, &c. By PHILIPPE DARYL, B.A. 2/6 
 
 Painting Popularly Explained. 
 
 By T. J. GULLICK, Painter, and JOHN TIMES, F.S.A. Including Frasco, 
 Oil, Mosaic, Water Colour, Water-Glass, Tempera, Encaustic, Miniature, 
 Painting on Ivory, Vellum, Pottery, Enamel, Glass, &c. Fifth Edition 5/O 
 
 A Dictionary of Terms used in Architecture, Build- 
 ing, Engineering, Mining, Metallurgy, Archae- 
 ology, the Fine Arts, &c. 
 
 By JOHN WEALE. Sixth Edition. Edited by ROBT. HUNT, F.R.S. 
 Numerous Illustrations 5/0 
 
 Music : 
 
 A Rudimentary and Practical Treatise. With numerous Examples. By 
 CHARLES CHILD SPENCER 2/6 
 
 Pianoforte, 
 
 The Art of Playing the. With numerous Exercises and Lessons. By 
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 The House Manager. 
 
 Being a Guide to Housekeeping, Practical Cookery, Pickling and Preserv- 
 ing, Household Work, Dairy Management, Cellarage of Wines, Home- 
 brewing and Wine- making, Stable Economy, Gardening Operations, Sac. 
 By AN OLD HOUSEKEEPER 3/6 
 
 Manual of Domestic Medicine. 
 
 By R. GOODING, M.D. Intended as a Family Guide in all cases of 
 Accident and Emergency Third Edition, carefully revised . . 2/0 
 
 Management of Health. 
 
 A Manual of Home and Personal Hygiene. By Rev. JAMES BAIRD 1 /O 
 
 Natural Philosophy, 
 
 For the Use of Beginners. By CHARLES TOMLINSON, F.R.S. . .1/6 
 
 The Electric Telegraph, 
 
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 By R. SABINE, C.E., F.S.A., &c 3/O 
 
 Handbook of Field Fortification. 
 
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 Logic, 
 
 Pure and Applied. By S. H EMMENS. Third Edition . . -1/6 
 
 Locke on the Human Understanding, 
 
 Selections from. With Notes by S. H. EMMENS . . . -1/6 
 
 The Compendious Calculator 
 
 (Intuitive Calculations}. Or Easy and Concise Methods of Performing the 
 various Arithmetical Operations required in Commercial and Business 
 Transactions ; together with Useful Tables, &o By DANIEL O'GoRMAN. 
 Twenty-seventh Edition, carefully revised by C. NORRIS . . .2/6 
 
WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 15 
 Measures, Weights, and Moneys of all Nations. 
 
 With an Analysis of the Christian, Hebrew, and Mahometan Calendars. 
 By W. S. B. WOOLHOUSE, F.R.A.S., F.S.S. Seventh Edition . 2/6 
 
 Grammar of the English Tongue, 
 
 Spoken and Written. With an Introduction to the Study of Comparative 
 Philology. By HYDE CLARKE, D.C.L. Fifth Edition. . . -1/6 
 
 Dictionary of the English Language. 
 
 As Spoken and Written. Containing above 100,000 Words. By HVDE 
 
 CLARKE, D.C.L 3/6 
 
 Comj> etc with the GRAMMAR 5/6 
 
 Composition and Punctuation, 
 
 Familiarly Explained for those who have neglected the Study of Grammar. 
 By JUSTIN BRENAN. i8th Edition 1/6 
 
 French Grammar. 
 
 With Complete and Concise Rules on the Genders of French Nouns. By 
 G. L. STRAUSS, Ph.D 1/6 
 
 English-French Dictionary. 
 
 Comprising a large number of Terms used in Engineering, Mining, &c. 
 By ALFRED ELWES 2/0 
 
 French Dictionary. 
 
 In two Parts I. French- English. II. English-French, complete in 
 One Vol . 3/0 
 
 *** Or with the GRAMMAR, 4/6- 
 
 French and English Phrase Book. 
 
 Containing Introductory Lessons, with Translations, Vocabularies of Words, 
 Collection of Phrases, and Easy Familiar Dialogues . . . .1/6 
 
 German Grammar. 
 
 Adapted for English Students, from Heyse's Theoretical and Practical 
 Grammar, by Dr. G. L. STRAUSS 1/6 
 
 German Triglot Dictionary. 
 
 By N. E. S. A. HAMILTON. Part I. German-French-English. Part II. 
 English-German-French. Part III. French-German-English . . 3/0 
 
 German Triglot Dictionary. 
 
 (As above). Together with German Grammar, in One Volume . 5/0 
 
 Italian Grammar. 
 
 Arranged in Twenty Lessons, with Exercises. By ALFRED ELWES. 1 /6 
 
 Italian Triglot Dictionary, 
 
 Wherein the Genders of all the Italian and French Nouns are carefully 
 noted down. By ALFRED ELWES. Vol. I. Italian-English-French. 2/6 
 
 Italian Triglot Dictionary. 
 
 By ALFRED ELX\ES. Vol.2. English-French-Italian. . . 2/6 
 
 Italian Triglot Dictionary. 
 
 By ALFRED ELWES. Vol. 3. French-Italian-English. . . . 2/6 
 
 Italian Triglot Dictionary. 
 
 (As above). In One Vi-1 7/6 
 
 Spanish Grammar. 
 
 In a Simple and Practical Form. With Exercises. By ALFRED ELWES 1 /Q 
 
 Spanish-English and English-Spanish Dictionary. 
 
 Including a large number of Technical Terms used in Mining, Engineering, 
 &c., with the proper Accents and the Gender of every Noun. By ALFRED 
 
 ELWES 4/O 
 
 %* Or -with the GRAMMAR, 6/0- 
 
16 WEALE'S SCIENTIFIC AND TECHNICAL SERIES. 
 
 Portuguese Grammar, 
 
 In a Simple and Practical Form. With Exercises. By ALFRED ELWES 1 fQ 
 
 Portuguese -English and English -Portuguese Dic- 
 tionary. 
 
 Including a large number of Technical Terms used in Mining, Engineering, 
 &c., with the proper Accents and the Gender of every Noun. By ALFRED 
 
 ELWES. Third Ecition, revised . Q/Q 
 
 V Or with the GRAMMAR, 7/Q. 
 Animal Physics, 
 
 Handbook of. By DIONVSIUS LARDNER, D.C.L. With 520 Illustrations. 
 
 In One Vol. (732 pages), cloth boards 7/6 
 
 *** Sold also in Two Parts, as follows : 
 
 ANIMAL PHYSICS. By Dr. LARDNER. Part I., Chapters I. VII. 4/Q 
 ANIMAL PHYSICS. By Dr. LARDNER. Part II., Chapters VIII. XVIII 
 
 3/0 
 
 ERADP.URY, AGNEW, & CO. LD., PRINTERS, LONDON AND TONBRIDGE. 
 
 
7, STATIONERS' HALL COURT, LONDON, E.G. 
 
 CROSBY LOCKWOOD & SON'S 
 Catalo0u^ of 
 
 Scientific, Technical and 
 Industrial Books. 
 
 PAGE 
 
 MECHANICAL ENGINEERING . 1 
 
 CIVIL ENGINEERING .... 9 
 
 MARINE ENGINEERING. &c. . 17 
 
 MINING & METALLURGY . . 19 
 
 ELECTRICITY 23 
 
 ARCHITECTURE & BUILDING . 25 
 
 SANITATION & WATER SUPPLY 27 
 
 CARPENTRY & TIMBER . . 28 
 
 PAGE 
 
 DECORATIVE ARTS 30 
 
 NATURAL SCIENCE 32 
 
 CHEMICAL MANUFACTURES . 34 
 
 INDUSTRIAL ARTS 
 
 COMMERCE, TABLES, &c. . . 
 AGRICULTURE & GARDENING- 
 AUCTIONEERING, VALUING. &C. 
 LAW & MISCELLANEOUS. 
 
 36 
 41 
 43 
 46 
 47 
 
 MECHANICAL ENGINEERING, &c. 
 
 THE MECHANICAL ENGINEER'S POCKET=BOOK. 
 
 Comprising Tables, Formulas, Rules, and Data : A Handy Book of Reference 
 for Daily Use in Engineering Practice. By D. KINNEAR CLARK, M. Inst. C.E., 
 Third Edition, Revised. Small 8vo, 700 pp., bound in flexible Leather Cover, 
 
 rounded corners 6/O 
 
 SUMMARY OF CONTENTS: MATHEMATICAL TABLES. MEASUREMENT OF SUR- 
 FACES AND SOLIDS. ENGLISH AND FOREIGN WEIGHTS AND MEASURES. MONEYS. 
 SPECIFIC GRAVITY, WEIGHT, AND VOLUME. MANUFACTURED METALS. STEEL PIPES. 
 BOLTS AND NUTS. SUNDRY ARTICLES IN WROUGHT AND CAST IRON, COPPER. 
 BRASS, LEAD, TIN, ZINC. STRENGTH OF TIMBER. STRENGTH OF CAST IRON. 
 STRENGTH OF WROUGHT IRON. STRENGTH OF STEEL. TENSILE STRENGTH OF 
 COPPER, LEAD, &c. RESISTANCE OF STONES AND OTHER BUILDING MATERIALS. 
 RIVETED JOINTS IN BOILER PLATES. BOILER SHELLS. WIRE ROPES AND HEMP 
 ROPES. CHAINS AND CHAIN CABLES. FRAMING. HARDNESS OF METALS, ALLOYS, AND 
 STONES. LABOUR OF ANIMALS. MECHANICAL PRINCIPLES. GRAVITY AND FALL OF 
 BODIES. ACCELERATING AND RETARDING FORCES. MILL GEARING, SHAFTING, &c. 
 TRANSMISSION OF MOTIVE POWER. HEAT. COMBUSTION: FUELS. WARMING, VENTI 
 LATION, COOKING STOVES. STEAM. STEAM ENGINES AND BOILERS. RAILWAYS. 
 TRAMWAYS. STEAM SHIPS. PUMPING STEAM ENGINES AND PUMPS. COAL GAS, GAS 
 ENGINES, &c. AIR IN MOTION. COMPRESSED AIR. HOT AIR ENGINES. WATER 
 POWER. SPEED OF CUTTING TOOLS. COLOURS. ELECTRICAL ENGINEERING. 
 
 " Mr. Clark manifests what is an innate perception of what is likely to be useful in a pocket- 
 book, and he is really unrivalled in the art of condensation. It is very difficult to hit upon any 
 mechanical engineering subject concerning which this work supplies no information, and the 
 excellent index at the end adds to its utility. In one word, it is an exceedingly handy and efficient 
 tool, possessed of which the engineer will be saved many a wearisome calculation, or yet more 
 wearisome hunt through various text-books and treatises, and, as such, we can heartily recommend 
 it to our readers." The Engineer. 
 
 " It would be found difficult to compress more matter within a similar compass, or produce a. 
 book of 650 pages which should be more compact or convenient for pocket reference. . . . Will 
 be appreciated by mechanical engineers of all classes." Practical Engineer. 
 
CROSBY LOCK WOOD &> SON'S CATALOGUE. 
 MR. MUTTON'S PRACTICAL HANDBOOKS. 
 
 THE WORKS' MANAGER'S HANDBOOK. 
 
 Comprising Modern Rules, Tables, and Data. For Engineers, Millwrights, 
 and Boiler Makers ; Tool Makers, Machinists, and Metal Workers ; Iron and 
 Brass Founders, &c. By W. S. HUTTON, Civil and Mechanical Engineer, 
 Author of "The Practical Engineer's Handbook." Fifth Edition, carefully 
 Revised, with Additions. In One handsome Volume, medium 8vo, strongly 
 bound . . 15/O 
 
 Q^F"" The Author having compiled Rules and Data for his own use in a great 
 variety of modern engineering work, and having found his notes extremely useful, 
 decided to publish them revised to date believing that a practical work, suited to 
 the DAILY REQUIREMENTS OF MODERN ENGINEERS, would be favourably receiv ed. 
 
 "Of this edition we may repeat the appreciative remarks we made upon the first and third. 
 Since the appearance of the latter very considerable modifications have been made, although the 
 total number of pages remains almost the same. It is a very useful collection of rules, tables, and 
 workshop and drawing office data." The Engineer, May ip, 1895. 
 
 " The author treats every subject from the point of view of one who has collected workshop 
 notes for application in workshop practice, rather than from the theoretical or literary aspect. The 
 volume contains a great deal of that kind of information which is gained only by practical experience, 
 and is seldom written in books." The Engineer, June g, 1885. 
 
 " The volume is an exceedingly useful one, brimful with engineer's notes, memoranda, and 
 rules, and well worthy of being on every mechanical engineer's bookshelf." Mechanical World. 
 
 " The information is precisely that likely to be required in practice. . . . The work forms 
 a desirable addition to the library not only of the works' manager, but of any one connected with 
 general engineering." Mining Journal. 
 
 " Brimful of useful information, stated in a concise form, Mr. Hutton's books have met a 
 pressing want among engineers. The book must prove extremely useful to every practical man 
 possessing a copy." Practical Engineer. 
 
 THE PRACTICAL ENGINEER'S HANDBOOK. 
 
 Comprising a Treatise on Modern Engines and Boilers, Marine, Locomotive, 
 and Stationary. And containing a large collection of Rules and Practical 
 Data relating to Recent Practice in Designing and Constructing all kinds of 
 Engines, Boilers, and other Engineering work. The whole constituting a com- 
 prehensive Key to the Board of Trade and other Examinations for Certificates 
 of Competency in Modern Mechanical Engineering. By WALTER S. HUTTON, 
 Civil and Mechanical Engineer, Author of The Works' Manager's Handbook 
 for Engineers," &c. With upwards of 370 Illustrations. Fifth Edition, 
 Revised with Additions. Medium 8vo, nearly 500 pp., strongly bound. 
 
 (Just Published. 1 8/O 
 
 BBP- This Work is designed as a companion to the Author's "WORKS' 
 MANAGER'S HANDBOOK." It possesses many new and original features, and con- 
 tains, like its predecessor, a quantity of matter not originally intended for publication, 
 but collected by the Author for his own use in the construction of a great variety of 
 MODERN ENGINEERING WORK. 
 
 The information is given in a condensed and concise form, and is illustrated by 
 upwards of 370 Woodcuts; and comprises a quantity of tabulated matter of great 
 value to all engaged in designing, constructing, or estimating for ENGINES, BOILERS, 
 and OTHER ENGINEERING WORK. 
 
 "We have kept it at hand for several weeks, referring to it as occasion arose, and we have not 
 on a single occasion consulted its pages without finding the information of which we were in quest." 
 Athenaum. 
 
 "A thoroughly good practical handbook, which no engineer can go through without learning 
 something that will be of service to him." Marine Engineer. 
 
 " An excellent book of reference for engineers, and a valuable text-book for students of 
 engineering. " Scotsman. 
 
 "This valuable manual embodies the results and experience of the leading authorities on 
 mechanical engineering." Building News. 
 
 "The author has collected together a surprising quantity of rules and practical data, and has 
 shown much judgment in the selections he has made. . . . There is no doubt that this book is 
 one of the most useful of its kind published, and will be a very popular compendium." Engineer. 
 
 " A mass of information set down in simple language, and in such a form that it can be easily 
 referred to at any time. The matter is uniformly good and well chosen, and is greatly elucidated 
 by the illustrations. The book will find its way on to most engineers' shelves, where it will rank as 
 one of the most useful books of reference." Practical Engineer. 
 
 " Full of useful information, and should be found on the office shelf of all practical engineers. 
 English Mechanic. 
 
MECHANICAL ENGINEERING, &c. 
 
 MR. MUTTON'S PRACTICAL HANDBOOKS-><m*rf. 
 
 
 STEAM BOILER CONSTRUCTION. 
 
 A Practical Handbook for Engineers, Boiler-Makers, and Steam Users. 
 Containing a large Collection of Rules and Data relating to Recent Practice 
 in the Design, Construction, and Working of all Kinds of Stationary, Loco- 
 motive, and Marine Steam-Boilers. By WALTER S. HUTTON, Civil and 
 Mechanical Engineer, Author of " The Works' Manager's Handbook," "The 
 Practical Engineer's Handbook," &c. With upwards of 500 Illustrations. 
 Third Edition. Revised and much Enlarged, medium 8vo, cloth . . i 8/O 
 &^*~ THIS WORK is issued in continuation of the Series of Handbooks written 
 by the Author, viz. : " THE WORKS' MANAGER'S HANDBOOK " and " THE PRACTICAL 
 ENGINEER'S HANDBOOK," which are so highly appreciated by engineers for the 
 practical nature of their information ; and is consequently written in the same style 
 as those works. 
 
 The Author believes that the concentration, in a convenient form for easy 
 reference, of such a large amount of thoroughly practical information on Steam- 
 Boilers, will be of considerable service to those for whom it is intended, and he trusts 
 the book may be deemed worthy of as favourable a reception as has been accorded to 
 its predecessors. 
 
 " One of the best, if not the best, books on boilers that has ever been published. The infor- 
 mation is of the right kind, in a simple and accessible form. So far as generation is concerned, this 
 is, undoubtedly, the standard book on steam practice." Electrical Review. 
 
 " Every detail, both in boiler design and management, is clearly laid before the reader. The 
 volume shows that boiler construction has been reduced to the condition of one of the most exact 
 sciences ; and such a book is of the utmost value to they?;* de si'ecle Engineer and Works Manager."' 
 Marine Engineer. 
 
 " There has long been room for a modern handbook on steam boilers ; there is not that room 
 now, because Mr. Huttpn has filled it. It is a thoroughly practical book for those who are occupied 
 in the construction, design, selection, or use of boilers." Engineer. 
 
 " The book is of so important and comprehensive a character that it must find its way into the 
 libraries of every one interested in boiler using or boiler manufacture if they wish to be thoroughly 
 informed. We strongly recommend the book for the intrinsic value of its contents." Machinery 
 Market. 
 
 PRACTICAL MECHANICS' WORKSHOP COMPANION. 
 
 Comprising a great variety of the most useful Rules and Formulae in Mechanical 
 Science, with numerous Tables of Practical Data and Calculated Results for 
 Facilitating Mechanical Operations. By WILLIAM TEMPLETON, Author of 
 " The Engineer's Practical Assistant," &c., &c. Seventeenth Edition, Revised, 
 Modernised, and considerably Enlarged by WALTER S. HUTTON, C.E., Author 
 of "The Works' Manager's Handbook," "The Practical Engineer's Hand- 
 book," &c. Fcap. 8vo, nearly 500 pp., with 8 Plates and upwards of 250 Illus- 
 trative Diagrams, strongly bound for workshop or pocket wear and tear . 6/O 
 In its modernised form Hutton's ' Templeton ' should have a wide sale, for it contains much 
 valuable information which the mechanic will often find of use, and not a few tables and notes which- 
 he might look for in vain in other works. This modernised edition will be appreciated by all who 
 have learned to value the original editions of ' Templeton.'" English Mechanic. 
 
 " It has met with great success in the engineering workshop, as we can testify ; and there are 
 a great many men who, in a great measure, owe their rise in life to this little book." Building 
 News. 
 
 "This familiar text-book well known to all mechanics and engineers is of essential service 
 to the every-day requirements of engineers, millwrights, and the various trades connected with 
 engineering and building. The new modernised edition is worth its weight in gold." Building 
 News. (Second Notice.) 
 
 " This well-known and largely-used book contains information, brought up to date, of the 
 sort so useful to the foreman and draughtsman. So much fresh information has been introduced a 
 to constitute it practically a new book. It will be largely used in the office and workshop." 
 Mechanical World. 
 
 "The publishers wisely entrusted the task of revision of this popular, valuable, and useful 
 book to Mr. Hutton, than whom a more competent man they could not have found." Iron. 
 
 ENGINEER'S AND MILLWRIGHT'S ASSISTANT. 
 
 A Collection of Useful Tables, Rules, and Data. By WILLIAM TEMPLETON, 
 Seventh Edition, with Aditions. i8mo, cloth 2/6 
 
 "Occupies a foremost place among books of this kind. A more suitable present to ai* 
 apprentice to any of the mechanical trades could not possibly be made." Building News. 
 
 "A deservedly popular work. It should be in the 'drawer' of every mechanic." English 
 Mechanic. 
 
CROSBY LOCK WOOD & SON'S CATALOGUE. 
 
 THE MECHANICAL ENGINEER'S REFERENCE BOOK. 
 
 For Machine and Boiler Construction. In Two Parts. Part I. GENERAL 
 
 ENGINEERING DATA. Part II. BOILER CONSTRUCTION. With 51 Plates and 
 
 numerous Illustrations. By NELSON FOLEY, M.I.N.A. Second Edition, 
 
 Revised throughout and much Enlarged. Folio, half-bound, net . 3 3s. 
 
 PART I. MEASURES. CIRCUMFERENCES AND AREAS, &c., SQUARES, CUBES, 
 
 FOURTH POWERS. SQUARE AND CUBE ROOTS. SURFACE OF TUBES. RECIPROCALS. 
 
 LOGARITHMS. MENSURATION. SPECIFIC GRAVITIES AND WEIGHTS. WORK AND 
 
 POWER. HEAT. COMBUSTION. EXPANSION AND CONTRACTION. EXPANSION OF 
 
 GASES. STEAM. STATIC FORCES. GRAVITATION AND ATTRACTION. MOTION AND 
 
 COMPUTATION OF RESULTING FORCES. ACCUMULATED WORK. CENTRE AND RADIUS 
 
 OF GYRATION. MOMENT OF INERTIA. CENTRE OF OSCILLATION. ELECTRICITY. 
 
 STRENGTH OF MATERIALS. ELASTICITY. TEST SHEETS OF METALS. FRICTION. 
 
 TRANSMISSION OF POWER. FLOW OF LIQUIDS. FLOW OF GASES. AIR PUMPS, SURFACE 
 
 CONDENSERS, &c. SPEED OF STEAMSHIPS. PROPELLERS. CUTTING TOOLS. FLANGES. 
 
 COPPER SHEETS AND TUBES. SCREWS, NUTS, BOLT HEADS, &c. VARIOUS RECIPES 
 
 AND MISCELLANEOUS MATTER. WITH DIAGRAMS FOR VALVE-GEAR, BELTING AND 
 
 ROPES, DISCHARGE AND SUCTION PIPES, SCREW PROPELLERS, AND COPPER PIPES. 
 
 PART II. TREATING OF POWER OF BOILERS. USEFUL RATIOS. NOTES ON 
 CONSTRUCTION. CYLINDRICAL BOILER SHELLS. CIRCULAR FURNACES. FLAT 
 PLATES. STAYS. GIRDERS. SCREWS. HYDRAULIC TESTS. RIVETING. BOILER 
 SETTING, CHIMNEYS, AND MOUNTINGS. FUELS, &c. EXAMPLES OF BOILERS AND SPEEDS 
 OF STEAMSHIPS. NOMINAL AND NORMAL HORSE POWER. WITH DIAGRAMS FOR ALL 
 BOILER CALCULATIONS AND DRAWINGS OF MANY VARIETIES OF BOILERS. 
 
 " The book is one which every mechanical engineer may, with advantage to himself, add to 
 his library." Industries. 
 
 " Mr. Foley is well fitted to compile such a wqrlc. . . . The diagrams are a great feature 
 of the work. . . . Regarding the whole work, it may be very fairly stated that Mr. Foley has 
 produced a volume which will undoubtedly fulfil the desire of the author and become indispensable 
 to all mechanical engineers." Marine Engineer. 
 
 " We have carefully examined this work, and pronounce it a most excellent reference book 
 for the use of marine engineers." Journal of American Society of Naval Engineers. 
 
 COAL AND SPEED TABLES. 
 
 A Pocket Book for Engineers and Steam Users. By NELSON FOLEY, Author 
 
 of " The Mechanical Engineer's Reference Book." Pocket-size, cloth . 3/6 
 
 " These tables are designed to meet the requirements of every-day use ; are of sufficient scope 
 
 for most practical purposes, and may be commended to engineers and users of steam." Iron. 
 
 TEXT-BOOK ON THE STEAM ENGINE. 
 
 With a Supplement on GAS ENGINES, and PART II. on HEAT ENGINES. By 
 
 T. M. GOODEVE, M.A., Barrister-at-Law, Professor of Mechanics at the Royal 
 
 College of Science, London ; Author of " The Principles of Mechanics," " The 
 
 Elements of Mechanism, "c. Fourteenth Edition. Crown 8vo, cloth . 6/O 
 
 " Professor Goodeve has given us a treatise on the steam engine which will bear comparison 
 
 with anything written by Huxley or Maxwell, and we can award it no higher praise." Engineer. 
 
 " Mr. Goodeve's text-book is a work of which every young engineer should possess himself." 
 Mining Journal. 
 
 ON GAS ENGINES. 
 
 With Appendix describing a Recent Engine with Tube Igniter. By T. M. 
 
 GOODEVE, M.A. Crown 8vo, cloth 2/6 
 
 " Like all Mr. Goodeve's writings, the present is no exception in point of general excellence. 
 It is a valuable little volume." Mechanical ll'orld. 
 
 A TREATISE ON STEAM BOILERS. 
 
 Their Strength, Construction, and Economical Working. By R. WILSON, C.E. 
 Fifth Edition. 12010, cloth 6/O 
 
 ' The best treatise that has ever been published on steam boilers. Engineer. 
 "The author shows himself perfect master of his subject, and we heartily recommend all 
 employing steam power to possess themselves of the work." Kylancfs Iron Trade Circular. 
 
 THE MECHANICAL ENGINEER'S COMPANION 
 
 of Areas, Circumferences, Decimal Equivalents, in inches and feet, millimetres, 
 squares, cubes, roots, &c. ; Weights, Measures, and other Data. Also Prac- 
 tical Rules for Modern Engine Proportions. By R. EDWARDS. M.Inst.C.E. 
 Fcap. 8vo, cloth. [Just Published. 3/6 
 
 "A very useful little volume. It contains many tables, classified data and memoranda, 
 generally useful to engineers." Engineer. 
 
 " This small book is what it professes to be, viz. : ' a handy office companion,' giving as it 
 does, in a succinct form, a variety of information likely to be required by mechanical engineers in 
 their everyday office work." Nature. 
 
MECHANICAL ENGINEERING, 
 
 A HANDBOOK ON THE STEAM ENGINE. 
 
 With especial Reference to Small and Medium-sized Engines. For the Use of 
 Engine Makers, Mechanical Draughtsmen, Engineering Students, and users 
 of Steam Power. By HERMAN HAEOER, C.E. Translated from the German 
 with considerable additions and alterations, by H. H. P. POVVLES, A.M.I.C.E., 
 M.I.M.E. Second Edition, Revised. With nearly 1,100 Illustrations. 
 Crown 8vo, cloth 9/O 
 
 "A perfect encyclopaedia of the steam engine and its details, and one which must take a per- 
 manent place in English drawing-offices and workshops." A Foreman Pattern-maker. 
 
 "This is an excellent book, and should be in the hands of all who are interested in the con- 
 struction and design of medium-sized stationary engines. ... A careful study of its contents and 
 the arrangement of the sections leads to the conclusion that there is probably no other book like it 
 in this country. The volume aims at showing the results of practical experience, and it certainly 
 may claim a complete achievement of this idea." Nature. 
 
 " There can be no question as to its value. We cordially commend it to all concerned in the 
 design and construction of the steam engine." Mechanical World. 
 
 BOILER AND FACTORY CHIMNEYS. 
 
 Their Draught-Power and Stability. With a chapter on Lightning Conductors. 
 By ROBERT WILSON, A.I.C.E., Author oi "A Treatise on Steam Boilers," &c. 
 Crown 8vo, cloth 3/6 
 
 " A valuable contribution to the literature of scientific building." The Builder. 
 
 BOILER MAKER'S READY RECKONER & ASSISTANT. 
 
 With Examples of Practical Geometry and Templating, for the Use of Platers, 
 Smiths, and Riveters. By JOHN COURTNEY, Edited by D. K. CLARK, 
 M.I. C.E. Third Edition, 480 pp., with 140 Illustrations. Fcap. 8vo . 7/O 
 " No workman or apprentice should be without this book." Iron Trade Circular. 
 
 REFRIGERATING & ICE=MAKING MACHINERY. 
 
 A Descriptive Treatise for the Use of Persons Employing Refrigerating 
 and Ice-Making Installations, and others. By A. J. WALLIS-TAYLER, 
 A.-M. Inst. C.E. Second Edition, Revised and Enlarged. With Illustrations. 
 Crown 8vo, cloth. [JustPublished. 7/6 
 
 "Practical, explicit, and profusely illustrated." Glasgow Herald. 
 
 " We recommend the book, which gives the cost of various systems and illustrations showing 
 details of parts of machinery and general arrangements of complete installations." Builder. 
 
 " May be recommended as a useful description of the machinery, the processes, and of the 
 facts, figures, and tabulated physics of refrigerating. It is one of the best compilations on the 
 subject." Engineer. 
 
 THE LOCOMOTIVE ENGINE AND ITS DEVELOPMENT. 
 
 A Popular Treatise on the Gradual Improvements made in Railway Engines 
 between 1803 and 1896. By CLEMENT E. STRETTON, C.E. Fifth Edition, 
 Enlarged. With 120 Illustrations. Crown 8vo, cloth. [Just Published. 3/6 
 
 " Students of railway history and all who are interested in the evolution of the modern loco- 
 motive will find much to attract and entertain in this volume." The Times. 
 
 "The author of this work is well known to the railway world, and no one, probably, has a 
 better knowledge of the history and development of the locomotive. The volume before us should 
 be of value to all connected with the railway system of this country." Nature. 
 
 ENGINEERING ESTIMATES, COSTS, AND ACCOUNTS. 
 
 A Guide to Commercial Engineering. With numerous examples of Estimates 
 and Costs of Millwright Work, Miscellaneous Productions, Steam Engines and 
 Steam Boilers ; and a Section on the Preparation of Costs Accounts. By 
 A GENERAL MANAGER. Second Edition. 8vo, cloth. [Just Published. 1 2/O 
 
 " This is an excellent and very useful book, covering subject-matter in constant requisition in 
 every factory and workshop. . . . The book is invaluable, not only to the young engineer, but 
 also to the estimate department of every works." Kuilder. 
 
 " We accord the work unqualified praise. The information is given in a plain, straightforward 
 manner, and bears throughout, evidence of the intimate practical acquaintance of the author with 
 every phase of commercial engineering." Mechanical ll'orld. 
 
CROSBY LOCK WOOD & SON'S CATALOGUE. 
 
 AERIAL OR WIRE=ROPE TRAMWAYS. 
 
 Their Construction and Management. By A. J.WALLIS-TAYLER, A.M.Inst.C.E. 
 
 With 81 Illustrations. Crown 8vo, cloth. [Just Published. 7/6 
 
 "This is in its way an excellent volume. Without going into the minutiae of the subject, it 
 
 yet lays before its readers a very good exposition of the various systems of rope transmission in use, 
 
 and gives as well not a little valuable information about their working, repair, and management. 
 
 We can safely recommend it as a useful general treatise on the subject." The Engineer. 
 
 " Mr. Tayler has treated the subject as concisely as thoroughness would permit. The book 
 will rank with the best on this useful topic, and we recommend it to those whose business is the 
 transporting of minerals and goods." Mining Journal. 
 
 MOTOR CARS OR POWER=CARRIAGES FOR COMMON 
 
 ROADS. 
 
 By A. J. WALLIS-TAYLER, Assoc. Memb. Inst. C.E., Author of "Modern 
 
 Cycles," &c. 212 pp., with 76 Illustrations. Crown 8vo, cloth . . 4/6 
 
 " Mr. Wallis-Tayler's book is a welcome addition to the literature of the sub ;t, as it is the 
 
 production of an Engineer, and has not been written with a view to assist in tSo promotion of 
 
 companies. . . . The book is clearly expressed throughout, and is just the sort of work that 
 
 an engineer, thinking of turning his attention to motor-carriage work, would do well to read as a 
 
 preliminary to starting operations." Engineering. 
 
 PLATING AND BOILER MAKING. 
 
 A Practical Handbook for Workshop Operations. By JOSEPH G. HORNER, 
 
 A.M.I.M.E. 380 pp. with 338 Illustrations. Crown 8vo, cloth . . 7/6 
 
 " The latest production from the pen of this writer is characterised by that evidence of close 
 
 acquaintance with workshop methods which will render the book exceedingly acceptable to the 
 
 practical hand. We have no hesitation in commending the work as a serviceable and practical 
 
 handbook on a subject which has not hitherto received much attention from those qualified to deal 
 
 with it in a satisfactory manner." Mechanical World. 
 
 PATTERN MAKING. 
 
 A Practical Treatise, embracing the Main Types of Engineering Construction, 
 and including Gearing, both Hand and Machine-made, Engine Work, Sheaves 
 and Pulleys, Pipes and Columns, Screws, Machine Parts, Pumps and Cocks, 
 the Moulding of Patterns in Loam and Greensand, &c., together with the 
 methods of estimating the weight of Castings ; with an Appendix of Tables for 
 Workshop Reference. By JOSEPH G. HORNER, A.M.I.M.E. Second Edition, 
 Enlarged. With 450 Illustrations. Crown 8vo, cloth .... 7/6 
 " A well-written technical guide, evidently written by a man who understands and has prac- 
 tised what he has written about. . . . We cordially recommend it to engineering students, young 
 journeymen, and others desirous of being initiated into the mysteries of pattern-making." Btttifkr. 
 " More than 400 illustrations help to explain the text, which .is, however, always clear and ex- 
 plicit, thus rendering the work an excellent vade mecimi for the apprentice who desires to become 
 master of his trade." English Mechanic. 
 
 MECHANICAL ENGINEERING TERMS 
 
 (Lockwood's Dictionary of). Embracing those current in the Drawing Office, 
 Pattern Shop, Foundry, Fitting, Turning, Smiths', and Boiler Shops, &c., &c. 
 Comprising upwards of 6,000 Definitions. Edited by JOSEPH G. HORNER, 
 A.M.I.M.E. Second Edition, Revised, with Additions. Crown 8vo, cloth 7/6 
 "Just the sort of handy dictionary required by the various trades engaged in mechanical en- 
 gineering. The practical engineering pupil will find the book of great value in his studies, and every 
 foreman engineer and mechanic should have a copy." Building News. 
 
 " Not merely a dictionary, but, to a certain extent, also a most valuable guide. It strikes us 
 as a happy idea to combine with a definition of the phrase useful information on the subject of 
 which it treats." Machinery Market. 
 
 TOOTHED GEARING. 
 
 A Practical Handbook for Offices and Workshops. By JOSEPH HORNER, 
 
 A.M.I.M.E. With 184 Illustrations. Crown 8vo, cloth . . . 6/O 
 
 "We must give the book our unqualified praise for its thoroughness of treatment, and we can 
 
 heartily recommend it to all interested as the most practical book on the subject yet written." 
 
 Mechanical World. 
 
 FIRES, FIRE=ENGINES, AND FIRE BRIGADES. 
 
 With a History of Fire-Engines, their Construction, Use, and Manage- 
 ment ; Foreign Fire Systems ; Hints on Fire-Brigades, &c. By CHARLES 
 F. T. YOUNG, C.E. 8vo, cloth 1 4s. 
 
 " To such of our readers as are interested in the subject of fires and fire apparatus we cair 
 most heartily commend this book." Engineering. 
 
MECHANICAL ENGINEERING, &c. 
 
 STONE=WORKING MACHINERY. 
 
 A Manual dealing with the Rapid and Economical Conversion of Stone. With 
 
 Hints on the Arrangement and Management of Stone Works. By M. Powis 
 
 BALE, M.I. M.E. Second Edition, enlarged. With Illustrations. Crown 8vo, 
 
 cloth. [Just Published. Q/Q 
 
 " The book should be in the hands of every mason or student of stonework." Colliery 
 
 Guardian. 
 
 " A capital handbook for all who manipulate stone for building or ornamental purposes." 
 Machinery Market. 
 
 PUMPS AND PUMPING. 
 
 A Handbook for Pump Users. Being Notes on Selection, Construction, and 
 Management. By M. Powis BALE, M.I.M.E. Third Edition, Revised. 
 Crown 8vo, cloth. [Just Published. 2/6 
 
 " The matter is set forth as concisely as possible. In fact, condensation rather than diffuse- 
 ness has been the author's aim throughout ; yet he does not seem to have omitted anything likely to 
 be of use." Joiirnal of Gas Lighting. 
 
 " Thoroughly practical and simply and clearly written. Glasgow Herald. 
 
 MILLING MACHINES AND PROCESSES. 
 
 A Practical Treatise on Shaping Metals by Rotary Cutters. Including 
 Information on Making and Grinding the Cutters. By PAUL N. HASLUCK, 
 Author of " Lathe-Work." 352 pp. With upwards of 300 Engravings. Large 
 crown 8vo, cloth 1 2/6 
 
 " A new departure in engineering literature. . . . We dan recommend this work to all in- 
 terested in milling machines ; it is what it professes to be a practical treatise." Engineer. 
 
 " A capital and reliable book which will no doubt be of considerable service both to those 
 who are already acquainted with the process as well as to those who contemplate its adoption." 
 Industries. 
 
 LATHE=WORK. 
 
 A Practical Treatise on the Tools, Appliances, and Processes employed in 
 the Art of Turning. By PAUL N. HASLUCK. Fifth Edition. Crown 8vo, 
 cloth 5/O 
 
 " Written by a man who knows not only how work ought to be done, but who also knows how 
 to do it, and how to convey his knowledge to others. To all turners this book would be valuable." 
 Engineering. 
 
 " We can safely recommend the work to young engineers. To the amateur it will simply be 
 invaluable. To the student it will convey a great deal of useful information." Engineer. 
 
 SCREW-THREADS, 
 
 And Methods of Producing Them. With numerous Tables and complete 
 Directions for using Screw-Cutting Lathes. By PAUL N. HASLUCK, Author 
 of " Lathe- Work," &c. With Seventy-four Illustrations. Fourth Edition, 
 
 Re-written and Enlarged. Waistcoat-pocket size 1/6 
 
 " Full of useful information, hints and practical criticism. Taps, dies, and screwing tools 
 generally are illustrated and their actions described." Mechanical H'orld. 
 
 " It is a complete compendium of all the details of the screw-cutting lathe ; in fact a multum- 
 in-parvo on all the subjects it treats upon." Carpenter and Bitilder. 
 
 TABLES AND MEMORANDA FOR ENGINEERS, 
 
 MECHANICS, ARCHITECTS, BUILDERS, &c. 
 
 Selected and Arranged by FRANCIS SMITH. Sixth Edition, Revised, including 
 ELECTRICAL TABLES, FORMULAE, and MEMORANDA. Waistcoat-pocket size, 
 limp leather. [Just Published. 1 /6 
 
 " It would, perhaps, be as difficult to make a smalt pocket-book selection of notes and formulas 
 to suit ALL engineers as it would be to make a universal medicine ; but Mr. Smith's waistcoat- 
 pocket collection may be looked upon as a successful attempt." Engineer. 
 
 " The best example we have ever seen of 270 pages of useful matter packed into the dimen- 
 sions of a card-case." Building News. " A veritable pocket treasury of knowledge." Iron. 
 
 POCKET GLOSSARY OF TECHNICAL TERMS. 
 
 English-French, French-English ; with Tables suitable for the Architectural, 
 Engineering, Manufacturing, and Nautical Professions. By JOHN JAMES 
 FLETCHER, Engineer and Surveyor. Second Edition, Revised and Enlarged, 
 
 200 pp. Waistcoat-pocket size, limp leather 1/6 
 
 " It is a very great advantage for readers and correspondents in France and England to have 
 so large a number of the words relating to engineering and manufacturers collected in a lilliputian 
 volume. The little book will be useful both to students and travellers." Architect. 
 
 " The glossary of terms is very complete, and many of the Tables are new and well arranged. 
 We cordially commend the book." Mechanical World. 
 
8 CROSBY LOCK WOOD 6- SON'S CATALOGUE. 
 
 THE ENGINEER'S YEAR BOOK FOR 1899. 
 
 Comprising Formulae, Rules, Tables, Data and Memoranda in Civil, Mechanical, 
 
 Electrical, Marine and Mine Engineering. By H. R. KEMVE, A.M. Inst. C.E., 
 
 M.I.E.E., Technical Officer of the Engineer-in-Chief's Office, General Post 
 
 Office, London, Author of "A Handbook of Electrical Testing." "The 
 
 Electrical Engineer's Pocket-Book," &c. With about 900 Illustrations, specially 
 
 Engraved for the work. Crown 8vo, 750 pp., leather. [Just Published. 8/O 
 
 " Represents an enormous quantity of work, and forms a desirable book of reference." Tlte 
 
 Engineer. 
 
 " The volume is distinctly in advance of most similar publications in this country." 
 Engineering. 
 
 " This valuable and well-designed book of reference meets the demands of all descriptions of 
 engineers." Saturday Review. 
 
 " Teems with up-to-date information in every branch of engineering and construction.' 
 Building News. 
 
 "The needs of the engineering profession could hardly be supplied in a more admirable, 
 complete and convenient form. To say that it more than sustains all comparisons is praise of the 
 highest sort, and that may justly be said of it." Mining Journal. 
 
 "There is certainly room for the newcomer, which supplies explanations and directions, as 
 well as formulae and tables. It deserves to become one of the most successful of the technical 
 annuals. " A rchitect. 
 
 " Brings together with great skill all the technical information which an engineer has to use 
 day by day. It is in every way admirably equipped, and is sure to prove successful." Scotsman. 
 
 " The up-to-dateness of Mr. Kempe's compilation is a quality that will not be lost on the busy 
 people for whom the work is intended." Glasgow Herald. 
 
 THE PORTABLE ENGINE. 
 
 A Practical Manual on its Construction and Management. For the use 
 of Owners and Users of Steam Engines generally. By WILLIAM DYSON 
 WANSBROUGH. Crown 8vo, cloth ........ 3/6 
 
 " This is a work of value to those who use steam machinery. . . . Should be read by every 
 one who has a steam engine, on a farm or elsewhere." Mark Lane Express. 
 
 " We cordially commend this work to buyers and owners of steam-engines, and to those who 
 have to do with their construction or use." Timber Trades Journal. 
 
 " Such a general knowledge of the steam-engine as Mr. Wansbrough furnishes to the reader 
 should be acquired by all intelligent owners and others who use the steam-engine." Building News. 
 
 "An excellent text -book of this useful form of engine. The ' Hints to Purchasers' contain a 
 good deal of common-sense and practical wisdom." English Mechanic. 
 
 IRON AND STEEL. 
 
 A Work for the Forge, Foundry, Factory, and Office. Containing ready, 
 useful, and trustworthy Information for Ironmasters and their Stock-takers ; 
 Managers of Bar, Rail, Plate, and Sheet Rolling Mills ; Iron and Metal 
 Founders ; Iron Ship and Bridge Builders ; Mechanical, Mining, and Con- 
 sulting Engineers ; Architects, Contractors, Builders, &c. By CHARLES HOARE, 
 Author of "The Slide Rule," &c. Ninth Edition. 321110, leather . 6/O 
 
 " For comprehensiveness the book has not its equal." Iron. 
 
 " One of the best of the pocket books." English Mechanic. 
 
 CONDENSED MECHANICS. 
 
 A Selection of Formulae, Rules, Tables, and Data or the Use of Engineering 
 Students, Science Classes, &c. In accordance with the Requirements of the 
 Science and Art Department. By W. G. CRAWFORD HUGHES, A.M.I.C.E. 
 Crown 8vo, cloth ........... 2/6 
 
 The book is well fitted for those who are either confronted with practical problems in 
 
 ledge 
 
 their work, or are preparing for examination and wish to refresh their knowledge by going through 
 their formulae again." Marine Engineer. 
 
 "It is well arranged, and meets the wants of those for whom it is intended." Raihu ay News. 
 
 THE SAFE USE OF STEAM. 
 
 Containing Rules for Unprofessional Steam Users. By an ENGINEER. Seventh 
 Edition. Sewed ............ 60. 
 
 " If steam-users would but learn this little book by heart, boiler explosions would become 
 sensations by their rarity." English Mechanic. 
 
 HEATING BY HOT WATER. 
 
 With Information and Suggestions on the best Methods of Heating Public, 
 
 Private and Horticultural Buildings. By WALTER JONES. Second Edition. 
 
 With 96 Illustrations, crown 8vo, cloth . ... Net 2/6 
 
 "We confidently recommend all interested in heating by hot water to secure a copy of this 
 
 valuable little treatise." The Plumber and Decorator. 
 
CIVIL ENGINEERING, SURVEYING, &-c. 9 
 
 CIVIL ENGINEERING, SURVEYING, &c. 
 LIGHT RAILWAYS FOR THE UNITED KINGDOM, 
 
 INDIA, AND THE COLONIES. 
 
 A Practical Handbook setting forth the Principles on which Light Railways 
 should be Constructed, Worked, and Financed ; and detailing the Cost of 
 Construction, Equipment, Revenue and Working Expenses of Local Railways 
 already established in the above-mentioned countries, and in Belgium, France, 
 Switzerland, &c. By J. C. MACKAY, F.G.S., A.M. Inst.C.E. Illustrated 
 with Plates and Diagrams. Medium 8vo, cloth. [Just Published. 1 5/Q 
 
 " Mr. Mackay's volume is clearly and concisely written, admirably arranged, and freely 
 
 illustrated. The book is exactly what has been long wanted. We recommend it to all interested 
 
 in the subject. It is sure to have a wide sale." Railway News. 
 
 "Those who desire to have within reach general information concerning almost all the light 
 
 railway systems in the world will do well to buy Mr. Mackay's \x>ok.." Engineer. 
 
 lysyste 
 
 " This 
 
 kay': 
 
 work appears very opportunely, when the extension of the system on a large scale to 
 England is at last being mooted. In its pages we find all the information that the heart of man can 
 desire on the subject. . . . every detail in its story, founded on the experience of other countries 
 and applied to the possibilities of England, is put before us." Spectator. 
 
 PRACTICAL TUNNELLING. 
 
 Explaining in detail Setting-out the Works, Shaft-sinking, and Heading-driving, 
 Ranging the Lines and Levelling underground, Sub-Excavating, Timbering 
 and the Construction of the Brickwork of Tunnels, with the amount of Labour 
 required for, and the Cost of, the various portions of the work. By FREDERICK 
 W. SIMMS, M. Inst.C.E. Fourth Edition, Revised and Further Extended, 
 including the most recent (1895) Examples of Sub-aqueous and other Tunnels, 
 by D. KINNEAR CLARK, M. Inst. C.E. Imperial 8vo, with 34 Folding Plates 
 and other Illustrations. Cloth. [Just Published. 2 2s. 
 
 " The present (1896) edition has been brought right up to date, and is thus rendered a work to 
 which civil engineers generally should have ready access, and to which engineers who have con- 
 struction work can hardly afford to be without, but which to the younger members of the profession 
 i.i invaluable, as from its pages they can learn the state to which the science of tunnelling has 
 attained." Railway News. 
 
 "The estimation in which Mr. Simms's book has been held for many years cannot be more 
 truly expressed than in the words of the late Prof. Rankine : 'The best source of information on 
 the subject of tunnels is Mr. F. W. Simms's work on Practical Tunnelling.' " Architect. 
 
 THE WATER SUPPLY OF TOWNS AND THE CON- 
 STRUCTION OF WATER-WORKS. 
 
 A Practical Treatise for the Use of Engineers and Students of Engineering. 
 By W. K. BURTON, A.M. Inst. C.E., Professor of Sanitary Engineering in the 
 Imperial University, Tokyo, Japan, and Consulting Engineer to the Tokyo 
 Water-works. Second Edition, Revised and Extended. With numerous 
 Plates and Illustrations. Super-royal 8vo, buckram. [Just Published. 2S/O 
 I. INTRODUCTORY. II. DIFFERENT QUALITIES OF WATER. III. QUANTITY OF 
 WATER TO BE PROVIDED. IV. ON ASCERTAINING WHETHER A PROPOSED SOURCE OF 
 SUPPLY is SUFFICIENT. V. ON ESTIMATING THE STORAGE CAPACITY REQUIRED 
 TO BE PROVIDED. VI. CLASSIFICATION OF WATER-WORKS. VII. IMPOUNDING RESER- 
 VOIRS. VIII. EARTHWORK DAMS. IX. MASONRY DAMS. X. THE PURIFICATION OF 
 WATER. XI. SETTLING RESERVOIRS. XII. SAND FILTRATION. XIII. PURIFICATION 
 OF WATER BY ACTION OF IRON, SOFTENING OF WATER BY ACTION OF LIME, NATURAL 
 FILTRATION. XIV. SERVICE; OR CLEAN WATER RESERVOIRS WATER TOWERS STAND 
 PIPES. XV. THE CONNECTION OF SETTLING RESERVOIRS, FILTER BEDS AND SERVICE 
 RESERVOIRS. XVI. PUMPING MACHINERY. XVII. FLOW OF WATER IN CONDUITS- 
 PIPES AND OPEN CHANNELS. XVIII. DISTRIBUTION SYSTEMS. XIX. SPECIAL PRO- 
 VISIONS FOR THE EXTINCTION OF FIRE. XX. PIPES FOR WATER-WORKS. XXI. PRE- 
 VENTION OF WASTE OF WATER. XXII. VARIOUS APPLICATIONS USED IN CONNECTION 
 WITH WATER-WORKS. 
 
 APPENDIX I. By PROF. JOHN MILNE, F.R.S. CONSIDERATIONS CONCERNING THE 
 PROBABLE EFFECTS OF EARTHQUAKES ON WATER-WORKS, AND THE SPECIAL PRE- 
 CAUTIONS TO BE TAKEN IN EARTHQUAKE COUNTRIES. 
 
 APPENDIX II. By JOHN DE RIJK.E, C.E. ON SAND DUNES AND DUNE SAND AS 
 A SOURCE OF WATER SUPPLY. 
 
 " The chapter upon filtration of water is very complete, and the details of construction well 
 illustrated. . . . The work should be specially valuable to civil engineers engaged in work in 
 Japan, but the interest is by no means confined to that locality." Engineer. 
 
 " We congratulate the author upon the practical commonsense shown in the preparation of 
 this work. . . . The plates and diagrams have evidently been prepared with great care, and 
 cannot fail to be of great assistance to the student." Builder. 
 
 " The whole art of water- works construction is dealt with in a clear and comprehensive fashion 
 in this handsome volume. . . . Mr. Burton's practical treatise shows in all its sections the fruit 
 of independent study and individual experience. It is largely based upon his own practice in the 
 branch of engineering of which it treats." Saturday Review. 
 
CROSBY LOCK WOOD & SON'S CATALOGUE. 
 
 THE WATER SUPPLY OF CITIES AND TOWNS. 
 
 By WILLIAM HUMBER, A. M. Inst. C.E., and M. Inst. M.E., Author of " Cast 
 and Wrought Iron Bridge Construction," &c., &c. Illustrated with 50 Double 
 Plates, i Single Plate, Coloured Frontispiece, and upwards of 250 Woodcuts, 
 and containing 400 pp. of Text. Imp. 410, elegantly and substantially 
 
 half-bound in morocco Net 6 6s. 
 
 LIST OF CONTENTS. 
 
 I. HISTORICAL SKETCH OF SOME OF THE MEANS THAT HAVE BEEN ADOPTED FOR 
 THE SUPPLY OF WATER TO CITIES AND TOWNS. II. WATER AND THE FOREIGN MATTER 
 
 USUALLY ASSOCIATED WITH IT. III. RAINFALL AND EVAPORATION. IV. SPRINGS AND 
 
 THE WATER-BEARING FORMATIONS OF VARIOUS DISTRICTS. V. MEASUREMENT AND 
 ESTIMATION OF THE FLOW OF WATER. VI. ON THE SELECTION OF THE SOURCE OF 
 SUPPLY. VII. WELLS. VIII. RESERVOIRS. IX. THE PURIFICATION OF WATER. 
 X. PUMPS. XI. PUMPING MACHINERY. XII. CONDUITS. XIII. DISTRIBUTION OF WATER. 
 XIV. METERS, SERVICE PIPES, AND HOUSE FITTINGS. XV. THE LAW OF ECONOMY OF 
 WATER-WORKS. XVI. CONSTANT AND INTERMITTENT SUPPLY. XVII. DESCRIPTION OF 
 PLATES. APPENDICES, GIVING TABLES OF RATES OF 'SUPPLY, VELOCITIES, &c., &c., 
 
 TOGETHER WITH SPECIFICATIONS OF SEVERAL WORKS ILLUSTRATED, AMONG WHICH 
 WILL BE FOUND : ABERDEEN, BlDEFORD, CANTERBURY, DUNDEE, HALIFAX, LAMBETH, 
 ROTHERHAM, DUBLIN, AND OTHERS. 
 
 " The most systematic and valuable work upon water supply hitherto produced in English, or 
 in any other language. . . . Mr. Humber's work is characterised almost throughout by an 
 exhaustiveness much more distinctive of French and German than of English technical treatises." 
 Engineer. 
 
 RURAL WATER SUPPLY. 
 
 A Practical Handbook on the Supply of Water and Construction of Water- 
 works for small Country Districts. By ALLAN GREENWELL, A.M.I.C.E., 
 and W. T. CURRY, A.M.I.C.E., F.G.S. With Illustrations. Second Edition, 
 Revised. Crown 8vo, cloth. [Just Published. 5/O 
 
 " We conscientiously recommend it as a very useful book for those concerned in obtaining 
 water for small districts, giving a great deal of practical information in a small compass." Builder. 
 " The volume contains valuable information upon all matters connected with water supply. 
 . . It is full of details on points which are continually before water-works engineers." 
 Nature. 
 
 HYDRAULIC TABLES, CO=EFFICIENTS, & FORMUL/E. 
 
 For Finding the Discharge of Water from Orifices, Notches, Weirs, Pipes, and 
 
 Rivers. With New Formulae, Tables, and General Information on Rain-fall, 
 
 Catchment-Basins, Drainage, Sewerage, Water Supply for Towns and Mill 
 
 Power. By JOHN NEVILLE, Civil Engineer, M.R.I. A. Third Edition, 
 
 revised, with additions. Numerous Illustrations. Crown 8vo, cloth . 1 4/O 
 
 " It is, of all English books on the subject, the one nearest to completeness. . . . From 
 
 the good arrangement of the matter, the clear explanations and abundance of formulae, the carefully 
 
 calculated tables, and, above all, the thorough acquaintance with both theory and construction, 
 
 which is displayed from first to last, the book will be found to be an acquisition." Architect. 
 
 HYDRAULIC MANUAL. 
 
 Consisting of Working Tables and Explanatory Text. Intended as a Guide in 
 Hydraulic Calculations and Field Operations. By Lovvis D'A. JACKSON, 
 Author of "Aid to Survey Practice," "Modern Metrology," &c. Fourth 
 
 Edition, Enlarged. Large crown 8vo, cloth 1 6/O 
 
 " The author has had a wide experience in hydraulic engineering and has been a careful 
 
 observer of the facts which have come under his notice, and from the great mass of material at his 
 
 command he has constructed a manual which may be accepted as a trustworthy guide to this 
 
 branch of the engineer's profession." Engineering, 
 
 " The most useful feature of this work is its freedom from what is superannuated, and its 
 
 thorough adoption of recent experiments; the text is in fact in great part a short account of the 
 
 great modern experiments." Nature. 
 
 WATER ENGINEERING. 
 
 A Practical Treatise on the Measurement, Storage, Conveyance, and Utilisa- 
 tion of Water for the Supply of Towns, for Mill Power, and for other Purposes. 
 By C. SLAGG, A. M. Inst. C.E. Second Edition. Crown 8vo, cloth . 7/6 
 " As a small practical treatise on the water supply of towns, and on some applications of water- 
 power, the work is in many respects excellent." Engineering. 
 
 " The author has collated the results deduced from the experiments of the most eminent 
 authorities, and has presented them in a compact and practical form, accompanied by very clear 
 and detailed explanations. . . . The application of water as a motive power is treated very 
 carefully and exhaustively." Builder. 
 
CIVIL ENGINEERING, SURVEYING, &>c. 
 
 MASONRY DAMS FROM INCEPTION TO COMPLETION. 
 
 Including numerous Formulae, Forms of Specification and Tender, Pocket 
 Diagram of Forces, &c. For the use of Civil and Mining Engineers. By 
 C. F. COURTNEY, M. Inst. C.E. 8vo, cloth. [Just Published. 9/O 
 
 RIVER BARS. 
 
 The Causes of their Formation, and their Treatment by " Induced Tidal 
 Scour ; " with a Description of the Successful Reduction by this Method of 
 the Bar at Dublin. By I. J. MANN, Assist. Eng. to the Dublin Port and Docks 
 Board. Royal 8vo, cloth 7/6 
 
 " We recommend all interested in harbour works and, indeed, those concerned in _the 
 improvements of rivers generally to read Mr. Mann's interesting work on the treatment of river 
 bars." Engineer. 
 
 DRAINAGE OF LANDS, TOWNS AND BUILDINGS. 
 
 By G. D. DEMPSEY, C.E. Revised, with large Additions on RECENT PRAC- 
 TICE IN DRAINAGE ENGINEERING, by D. KINNEAR CI.ARK, M. Inst. C.E., 
 Author of "Tramways: their Construction and Working." Cr. 8vo, cloth . 4/6 
 " The new matter added to Mr. Dempsey's excellent work is characterised by the compre- ' 
 
 hensive grasp and accuracy of detail for which the name of Mr. D. K. Clark is a sufficient 
 
 voucher." Atfieiuzum. 
 
 TRAMWAYS: THEIR CONSTRUCTION AND WORKING. 
 
 Embracing a Comprehensive History of the System ; with an exhaustive 
 
 Analysis of the Various Modes of Traction, including Horse Power, Steam, 
 
 Cable Traction, Electric Traction, &c. ; a Description of the Varieties of 
 
 Rolling Stock ; and ample Details of Cost and Working Expenses. New 
 
 Edition, Thoroughly Revised, and Including the Progress recently made in 
 
 Tramway Construction, &c., &c. By D. KINNEAR CLARK, M. Inst. C.E. 
 
 With 400 Illustrations. 8vo, 780 pp., buckram. [Just Published. 28/O 
 
 " Although described as a new edition, this book is really a new one, a large part of it, which 
 
 covers historical ground, having been re-written and amplified ; while the parts which relate to all , 
 
 that has been done since 1882 appear in this edition only. It is sixteen years since the first edition 
 
 appeared, and twelve years since the supplementary volume to the first book was published. 
 
 After a lapse, then, of twelve years, it is obvious that the author has at his disposal a vast 
 
 quantity of descriptive and statistical information, with which he may, and has, produced a 
 
 volume of great value to all interested in tramway construction and working. The new volume is 
 
 one which will rank, among tramway engineers and those interested in tramway working, with his 
 
 world-famed book on railway machinery." The Engineer, March 8, 1895. 
 
 PRACTICAL SURVEYING. 
 
 A Text-Book for Students preparing for Examinations or for Survey-work in 
 the Colonies. By GEORGE W. USILL, A.M.I.C.E. With 4 Plates and up- 
 wards of 330 Illustrations. Fifth Edition, Revised and Enlarged. Including 
 Tables of Natural Sines, Tangents, Secants, &c. Crown 8vo, cloth 7/6 ; or, 
 on THIN PAPER, bound in limp leather, gilt edges, rounded corners, for 
 
 pocket use 1 2/6 
 
 " The best forms of instruments are described as to their construction, uses and modes 
 of employment, and there are innumerable hints on work and equipment such as the author, in 
 his experience as surveyor, draughtsman and teacher, has found necessary, and which the student 
 in his inexperience will find most serviceable." Engineer. 
 
 "The latest treatise in the English language on surveying, and we have no hesitation in say- 
 ing that the student will find it a better guide than any of its predecessors. Deserves to be 
 recognised as the first book which should be put in the hands of a pupil of Civil Engineering." 
 Architect. 
 
 AID TO SURVEY PRACTICE. 
 
 For Reference in Surveying, Levelling, and Setting-out ; and in Route Sur- 
 veys of Travellers by Land and Sea. With Tables, Illustrations, and Records. 
 By Lowis D'A. JACKSON, A.M.I.C.E. Second Edition, Enlarged. Large 
 crown 8vo, cloth 1 2/6 
 
 " Mr. Jackson has produced a valuable vade-mecum, for the surveyor. We can recommend 
 this book as containing an admirable supplement to the teaching of the accomplished surveyor." 
 
 " As a text-book we should advise all surveyors to place it in their libraries, and study well 
 the matured instructions afforded in its pages." Colliery Guardian. 
 
 " The author brings to his work a fortunate union of theory and practical experience which, 
 aided by a clear and lucid style of writing, renders the book a very useful one." Builder. 
 
12 CROSBY LOCK WOOD & SON'S CATALOGUE. 
 ENGINEER'S & MINING SURVEYOR'S FIELD BOOK. 
 
 Consisting of a Series of Tables, with Rules, Explanations of Systems, and 
 use of Theodolite for Traverse Surveying and plotting the work with minute 
 accuracy by means of Straight Edge and Set Square only ; Levelling with the 
 Theodolite, Casting-out and Reducing Levels to Datum, and Plotting Sections 
 in the ordinary manner; Setting-out Curves with the Theodolite by Tangential 
 Angles and Multiples with Right and Left-hand Readings of the Instrument ; 
 Setting-out Curves without Theodolite on the System of Tangential Angles by 
 Sets of Tangents and Offsets ; and Earthwork Tables to 80 feet deep, calcu- 
 lated for every 6 inches in depth. By W. DAVIS HASKOLL, C.E. With 
 numerous Woodcuts. Fourth Edition, Enlarged. Crown 8vo, cloth . 1 2/O 
 " The book is very handy ; the separate tables of sines and tangents to every minute will make 
 it useful for many other purposes, the genuine traverse tables existing all the ^xme."Athenaum. 
 
 "Every person engaged in engineering field operations will estimate the importance of such 
 a work and the amount of valuable time which will be saved by reference to a set of reliable tables 
 prepared with the accuracy and fulness of those given in this volume." Raihuay Ncivs. 
 
 LAND AND MARINE SURVEYING. 
 
 In Reference to the Preparation of Plans for Roads and Railways ; Canals, 
 Rivers, Towns' \Vater Supplies ; Docks and Harbours. With Description 
 and Use of Surveying Instruments. By W. DAVIS HASKOLL, C.E. Second 
 Edition, Revised, with Additions. Large crown 8vo, cloth . . . 9/O 
 " This book must prove of great value to the student. We have no hesitation in recom- 
 mending it, feeling assured that it will more than repay a careful study." Mechanical World. 
 
 " A most useful book for the student. We strongly recommend it as a carefully-written 
 and valuable text-book. It enjoys a well-deserved repute "among surveyors." Builder. 
 
 " This volume cannot fail to prove of the utmost practical utility. It may be safely recom- 
 mended to all students who aspire to become clean and expert surveyors." Mining Journal. 
 
 PRINCIPLES AND PRACTICE OF LEVELLING. 
 
 Showing its Application to Purposes of Railway and Civil Engineering in 
 the Construction of Roads ; with Mr. TELFOKD'S Rules for the same. By 
 FREDERICK W. SIMMS, F.G.S., M. Inst. C.E. Eighth Edition, with the 
 addition of LAW'S Practical Examples for Setting-out Railway Curves, and 
 TRAUTWINE'S Field Practice of Laying-out Circular Curves. With 7 Plates 
 
 and numerous Woodcuts, 8vo, cloth 8/6 
 
 *** TRAUTWINE on CURVES may be had separate 5/O 
 
 " The text-book on levelling in most of our engineering schools and colleges." Engineer. 
 "The publishers have rendered a substantial service to the profession, especially to the 
 younger members, by bringing out the present edition of Mr. Simms's useful work." Engineering. 
 
 AN OUTLINE OF THE METHOD OF CONDUCTING 
 
 A TRIGONOMETRICAL SURVEY. 
 
 For the Formation of Geographical and Topographical Maps and Plans, Mili- 
 tary Reconnaissance, LEVELLING, &c., with Useful Problems, Formulae, 
 and Tables. By Lieut. -General FROME, R.E. Fourth Edition, Revised and 
 partly Re-written by Major-General Sir CHARLES WARREN, G.C.M.G., R.E. 
 With 19 Plates and 115 Woodcuts, royal 8vo, cloth .... 1 6/O 
 " No words of praise from us can strengthen the position so well and so steadily maintained 
 by this work. Sir Charles Warren has revised the entire work, and made such additions as were 
 necessary to bring every portion of the contents up to the present date." Broad Arrow. 
 
 TABLES OF TANGENTIAL ANGLES AND MULTIPLES 
 
 FOR SETTING-OUT CURVES. 
 
 From 5 to 200 Radius. By A. BEAZELEY, M. Inst. C.E. 6th Edition, 
 Revised. With an Appendix on the use of the Tables for Measuring up 
 Curves. Printed on 50 Cards, and sold in a cloth box, waistcoat-pocket size. 
 
 [Just Published. 3/6 
 dolite, I 
 
 " Each table is printed on a card, which, placed on the theodolite, leaves the hands free 
 to manipulate the instrument no small advantage as regards the rapidity of work." Engineer. 
 
 " Very handy : a man may know that all his day's work must fall on two of these cards, which 
 he puts into his own card-case, and leaves the rest behind." Athenizum. 
 
 HANDY GENERAL EARTH=WORK TABLES. 
 
 Giving the Contents in Cubic Yards of Centre and Slopes of Cuttings and 
 Embankments from 3 inches to 80 feet in Depth or Height, for use with either 
 66 feet Chain or 100 feet Chain. By J. H. WATSON BUCK, M. Inst. C.E. 
 On a Sheet mounted in cloth case. [Just Published. 3/6 
 
CIVIL ENGINEERING, SURVEYING, &>c. 13 
 
 EARTHWORK TABLES. 
 
 Showing the Contents in Cubic Yards of Embankments, Cuttings, &c., of 
 
 Heights or Depths up to an average of 80 feet. By JOSEPH BROADBENT, C.E., 
 
 and FRANCIS CAMPIN, C.E. Crown 8vo, cloth ... . 5/O 
 
 " The way in which accuracy is attained, by a simple division of each cross section into three 
 
 elements, two in which are constant and one variable, is ingenious." Athenceunt. 
 
 A MANUAL ON EARTHWORK. 
 
 By ALEX. J. S. GRAHAM, C.E. With numerous Diagrams. Second Edition. 
 i8mo, cloth 2/6 
 
 THE CONSTRUCTION OF LARGE TUNNEL SHAFTS. 
 
 A Practical and Theoretical Essay. By J. H. WATSON BUCK, M. Inst. C.E., 
 Resident Engineer, L. and N. W. R. With Folding Plates, 8vo, cloth 1 2/O 
 " Many of the methods given are of extreme practical value to the mason, and the observa- 
 tions on the form of arch, the rules for ordering the stone, and the construction of the templates, 
 will be found of considerable use. We commend the book to the engineering profession." 
 Building News. 
 
 " Will be regarded by civil engineers as of the utmost value, and calculated to save much 
 time and obviate many mistakes." Colliery Guardian. 
 
 CAST & WROUGHT IRON BRIDGE CONSTRUCTION. 
 
 (A Complete and Practical Treatise on), including Iron Foundations. In 
 Three Parts. Theoretical, Practical, and Descriptive. By WILLIAM HUMBER, 
 A. M. Inst. C.E., and M. Inst. M.E. Third Edition, revised and much im- 
 proved, with 115 Double Plates(2o of which now first appear in this edition), 
 and numerous Additions to the Text. In 2 vols., imp. 410, half-bound in 
 
 morocco 6 1 6s. 60. 
 
 " A very valuable contribution to the standard literature of civil engineering. In addition to 
 elevations, plans, and sections, large scale details are given, which very much enhance the 
 instructive wortli of those illustrations." Civil Engineer and Architect's Journal. 
 
 "Mr. Number's stately volumes, lately issued in which the most important bridges 
 erected during the last five years, under the direction of the late Mr. Brunei, Sir W. Cubitt, 
 Mr. Hawkshaw, Mr. Page, Mr. Fowler, Mr. Hemans, and others among our most eminent 
 engineers, are drawn and specified in great detail." Engineer. 
 
 ESSAY ON OBLIQUE BRIDGES 
 
 (Practical and Theoretical). With 13 large Plates. By the late GEORGE 
 WATSON BUCK, M.I. C.E. Fourth Edition, revised by his Son, J. H. WATSON 
 BUCK, M.I. C.E. ; and with the addition of Description to Diagrams for 
 Facilitating the Construction of Oblique Bridges, by W. H. BARLOW, M.I. C.E. 
 
 Royal 8vo, cloth 1 2/O 
 
 "The standard text-book for all engineers regarding skew arches is Mr. Buck's treatise, 
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 "Mr. Buck's treatise is recognised as a standard text-book, and his treatment has divested 
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 architect, on a confessedly difficult subject, Mr. Buck's work is unsurpassed." Building News. 
 
 THE CONSTRUCTION OF OBLIQUE ARCHES 
 
 (A Practical Treatise on). By JOHN HART. Third Edition, with Plates. 
 Imperial 8vo, cloth 8/O 
 
 GRAPHIC AND ANALYTIC STATICS. 
 
 In their Practical Application to the Treatment of Stresses in Roofs, Solid 
 
 Girders, Lattice, Bowstring, and Suspension Bridges, Braced Iron Arches and 
 
 Piers, and other Frameworks. By R. HUDSON GRAHAM, C.E. Containing 
 
 Diagrams and Plates to Scale. With numerous Examples, many taken from 
 
 existing Structures. Specially arranged for Class-work in Colleges and 
 
 Universities. Second Edition, Revised and Enlarged. 8vo, cloth . 1 6/O 
 
 " Mr. Graham's book will find a place wherever graphic and analytic statics are used or 
 
 studied." Engineer. 
 
 " The work is excellent from a practical point of view, and has evidently been prepared 
 with much care. The directions for working are simple, and are illustrated by an abundance of 
 well-selected examples. It is an excellent text-book for the practical draughtsman." Athentettm. 
 
 PRACTICAL GEOMETRY. 
 
 For the Architect, Engineer, and Mechanic. Giving Rules for the Delineation 
 and Application of various Geometrical Lines, Figures, and Curves. By 
 
 E. W. TARN, M.A., Architect. 8vo, cloth 9/O 
 
 " No book with the same objects in view has ever been published in which the clearness of 
 the rules laid down and the illustrative diagrams have been so satisfactory." Scotsman. 
 
CROSBY LOCK WOOD & SON'S CATALOGUE. 
 
 THE GEOMETRY OF COMPASSES. 
 
 Or, Problems Resolved by the mere Description of Circles and the Use of 
 Coloured Diagrams and Symbols. By OLIVER BYRNE. Coloured Plates. 
 Crown 8vo, cloth 3/6 
 
 WEIGHTS OF WROUGHT IRON & STEEL GIRDERS. 
 
 A Graphic Table for Facilitating the Computation of the Weights of Wrought 
 Iron and Steel Girders, &c., for Parliamentary and other Estimates By 
 J. H. WATSON BUCK, M. Inst. C.E. On a Sheet 2/6 
 
 HANDY BOOK FOR THE CALCULATION OF STRAINS 
 
 In Girders and Similar Structures and their Strength. Consisting of Formula 
 and Corresponding Diagrams, with numerous details for Practical Applica- 
 tion, &c. By WILLIAM HUMBER, A. M. Inst. C.E., &c. Fifth Edition. 
 Crown 8vo, with nearly 100 Woodcuts and 3 Plates, cloth . . . "7/6 
 
 "The formulae are neatly expressed, and the diagrams gooAS'Athenceujn. 
 
 "We heartily commend this really handy book to our engineer and architect readers," 
 English Mechanic. 
 
 TRUSSES OF WOOD AND IRON. 
 
 Practical Applications of Science in Determining the Stresses, Breaking 
 Weights, Safe Loads, Scantlings, and Details of Construction. With Complete 
 Working Drawings. By WILLIAM GRIFFITHS, Surveyor, Assistant Master, 
 Tranmere School of Science and Art. Oblong 8vo, cloth . . . 4/6 
 " This handy little book enters so minutely into every detail connected with the con- 
 struction of roof trusses that no student need be ignorant of these matters." Practical Engineer. 
 
 THE STRAINS ON STRUCTURES OF IRONWORK. 
 
 With Practical Remarks on Iron Construction. By F. W. SHEILDS, M.I. C.E. 
 8vo, cloth 5/Q 
 
 A TREATISE ON THE STRENGTH OF MATERIALS. 
 
 With Rules for Application in Architecture, the Construction of Suspension 
 Bridges, Railways, &c. By PETER BARLOW, F.R.S. A new Edition, revised 
 by his Sons, P. W. BARLOW, F.R.S., and W. H. BARLOW, F.R.S. ; to which 
 are added, Experiments by HODGKINSON, FAIRBAIRN, and KIRKALDY ; and 
 Formulae for calculating Girders, &c. Arranged and Edited by WM. HUMBER, 
 A. M. Inst. C.E. Demy 8vo, 400 pp., with 19 large Plates and numerous 
 
 Woodcuts, cloth . -| 8/O 
 
 " Valuable alike to the student, tyro, and the experienced practitioner, it will always rank 
 
 in future as it has hitherto done, as the standard treatise on that particular subject." Engineer 
 
 " As a scientific work of the first class, it deserves a foremost place on the bookshelves ef 
 
 every civil engineer and practical mechanic." English Mechanic. 
 
 STRENGTH OF CAST IRON AND OTHER METALS. 
 
 By THOMAS TREDGOLD, C.E. Fifth Edition, including HODGKINSON'S Experi- 
 mental Researches. 8vo, cloth ~\ 2/O 
 
 SAFE RAILWAY WORKING. 
 
 A Treatise on Railway Accidents, their Cause and Prevention ; with a De- 
 scription of Modern Appliances and Systems. By CLEMENT E. STRETTON, 
 C.E., Vice-President and Consulting Engineer, Amalgamated Society of 
 Railway Servants. With Illustrations and Coloured Plates. Third Edition, 
 Enlarged. Crown 8vo, cloth ......... 3/6 
 
 "A book for the engineer, the directors, the managers; and, in short, all who wish for 
 
 information on railway matters will find a perfect encyclopaedia in ' Safe Railway Working.' " 
 
 Rail-way Review. 
 
 "We commend the remarks on railway signalling to all railway managers, especially where 
 
 i uniform code and practice is advocated." Herepath's Raihuay Journal. 
 
 EXPANSION OF STRUCTURES BY HEAT. 
 
 By JOHN KEILY, C.E., late of the Indian Public Works Department. Crown 
 8vo, cloth -. , .V 3/6 
 
 " The aim the author has set before him, viz., to show the effects of heat upon metallic and 
 Jther structures, is a laudable one, for this is a branch of physics upon which the engineer or 
 architect can find but little reliable and comprehensive data in books." Builder 
 
CIVIL ENGINEERING, SURVEYING, &>c. 15 
 
 RECORD OF THE PROGRESS OF MODERN 
 ENGINEERING. 
 
 Complete in Four Volumes, imperial 410, half-morocco, price 1 2 1 2s. 
 
 Each volume sold separately, as follows : 
 
 FIRST SERIES, Comprising Civil, Mechanical, Marine, Hydraulic, Railway, 
 Bridge, and other Engineering Works, &c. By WILLIAM HUMBER, 
 A. M. Inst. C.E.,&c. Imp. 410, with 36 Double Plates, drawn to a large scale, 
 Photographic Portrait of John Hawkshaw, C.E., F.R.S., &c., and copious 
 descriptive Letterpress, Specifications, &c. Half-morocco . . 3 3s. 
 
 LIST OF THE PLATES AND DIAGRAMS. 
 
 VICTORIA STATION AND ROOF, L. B. & S. C. R. (8 PLATES) ; SOUTHPORT PIER 
 (2 PLATES) ; VICTORIA STATION AND ROOF, L. C. & D. AND G. w. R. (6 PLATES) ; ROOF 
 OF CREMORNE Music HALL; BRIDGE OVER G. N. RAILWAY: ROOF OF STATION, 
 DUTCH RHENISH RAIL. (2 PLATES); BRIDGE OVER THE THAMES, WEST LONDON 
 EXTENSION RAILWAY (5 PLATES); ARMOUR PLATES: SUSPENSION BRIDGE, THAMES 
 (4 PLATES); THE ALLEN ENGINE; SUSPENSION BRIDGE, AVON (3 PLATES); UNDER- 
 GROUND RAILWAY (3 PLATES). 
 
 HUMBER'S PROGRESS OF MODERN ENGINEERING. 
 
 SECOND SERIES. Imp. 410, with 3 Double Plates, Photographic Portrait of 
 Robert Stephenson, C.E., M.P., F.R.S., &c., and copious descriptive Letter- 
 press, Specifications, &c. Half-morocco ...... 3 3s. 
 
 LIST OF THE PLATES AND DIAGRAMS. 
 
 BlRKENHEAD DOCKS, LOW WATER BASIN (15 PLATES) ; CHARING CROSS STATION 
 ROOF, C. C. RAILWAY (3 PLATES); DIGSVVELL VIADUCT, GREAT NORTHERN RAILWAY; 
 ROBBERY AVOOD VIADUCT, GREAT NORTHERN RAILWAY; IRON PERMANENT WAY; 
 CLYDACH VIADUCT, MERTHYR, TREDEGAR, AND ABERGAVENNY RAILWAY ; EBBW 
 VIADUCT, MERTHYR, TREDEGAR, AND ABERGAVENNY RAILWAY; COLLEGE WOOD- 
 VIADUCT, CORNWALL RAILWAY; DUBLIN WINTER PALACE ROOF (3 PLATES); BRIDGE 
 OVER THE THAMES, L. C. & D. RAILWAY (6 PLATES); ALBERT HARBOUR, GREENOCK 
 (4 PLATES). 
 
 HUMBER'S PROGRESS OF MODERN ENGINEERING. 
 
 THIRD SERIES. Imp. 410, with 40 Double Plates, Photographic Portrait of 
 J. R. M 'Clean, late Pres. Inst. C.E., and copious descriptive Letterpress, 
 
 Specifications, &c. Half-morocco 3 3s_ 
 
 LIST OF THE PLATES AND DIAGRAMS. 
 
 MAIN DRAINAGE, METROPOLIS. North. Side. MAP SHOWING INTERCEPTION OF 
 SEWERS; MIDDLE LEVEL SEWER (2 PLATES); OUTFALL SEWER, BRIDGE OVER RIVER 
 LEA (3 PLATES) ; OUTFALL SEWER, BRIDGE OVER MARSH LANE, NORTH WOOLWICH- 
 RAILWAY, AND BOW AND BARKING RAILWAY JUNCTION ; OUTFALL SEWER, BRIDGE OVER 
 
 Bow AND BARKING RAILWAY (3 PLATES) ; OUTFALL SEWER, BRIDGE OVER EAST LONDON- 
 WATER-WORKS' FEEDER (2 PLATES) ; OUTFALL SEWER RESERVOIR (2 PLATES) ; OUTFALL 
 SEWER, TUMBLING BAY AND OUTLET; OUTFALL SEWER, PENSTOCKS. South Side. 
 OUTFALL SEWER, BERMONDSEY BRANCH (2 PLATES) ; OUTFALL SEWER, RESERVOIR ANL> 
 OUTLET (4 PLATES) ; OUTFALL SEWER, FILTH HOIST ; SECTIONS OF SEWERS (NORTH AND- 
 SOUTH SIDES). 
 
 THAMES EMBANKMENT. SECTION OF RIVER WALL; STEAMBOAT PIER, WEST- 
 MINSTER (2 PLATES) ; LANDING STAIRS BETWEEN CHARING CROSS AND WATERLOO- 
 BRIDGES ; YORK GATE (2 PLATES) ; OVERFLOW AND OUTLET AT SAVOY STREET SEWER 
 (3 PLATES); STEAMBOAT PIER, WATERLOO BRIDGE (3 PLATES) ; JUNCTION OF SEWERS, 
 PLANS AND SECTIONS; GULLIES, PLANS AND SECTIONS; ROLLING STOCK ; GRANITE 
 AND IRON FORTS. 
 
 HUMBER'S PROGRESS OF MODERN ENGINEERING. 
 
 FOURTH SERIES. Imp. 4to, with 36 Double Plates, Photographic Portrait of 
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 fications, &c. Half-morocco 3 3 S . 
 
 LIST OF THE PLATES AND DIAGRAMS. 
 
 ABBEY MILLS PUMPING STATION, MAIM DRAINAGE, METROPOLIS {^ PLATES) ; 
 BARROW DOCKS (5 PLATES): MANQUIS VIADUCT, SANTIAGO AND VALPARAISO RAILWAY, 
 (2 PLATES); ADAM'S LOCOMOTIVE, ST. HELEN'S CANAL RAILWAY (2 PLATES); CANNON- 
 STREET STATION ROOF, CHARING CROSS RAILWAY (3 PLATES); ROAD BRIDGE OVER 
 THE RIVER MOKA (2 PLATES): TELEGRAPHIC APPARATUS FOR MESOPOTAMIA ; VIADUCT 
 OVER THE RIVER WYE, MIDLAND RAILWAY (3 PLATES) : ST. GERMANS VIADUCT, 
 CORNWALL RAILWAY (2 PLATES); WROUGHT-IRON CYLINDER FOR DIVING BELL; 
 MlLLWALL DOCKS (6 PLATES): MILROY'S PATENT EXCAVATOR ; METROPOLITAN DIS- 
 TRICT RAILWAY (6 PLATES) ; HARBOURS, PORTS, AND BREAKWATERS (3 PLATES). 
 
1 6 CROSBY LOCK WOOD &- SON'S CATALOGUE. 
 
 THE POPULAR WORKS OF MICHAEL REYNOLDS. 
 LOCOMOTIVE ENGINE DRIVING. 
 
 A Practical Manual for Engineers in Charge of Locomotive Engines. By 
 MICHAEL REYNOLDS, Member of the Society of Engineers, formerly Loco- 
 motive Inspector, L. B. & S. C. R. Ninth Edition. Including a KEY TO 
 THE LOCOMOTIVE ENGINE. With Illustrations and Portrait of Author. 
 
 Crown 8vo, cloth 4/6 
 
 " Mr. Reynolds has supplied a want, and has supplied it well. We can confidently recom- 
 mend the book not only to the practical driver, but to everyone who takes an interest in the 
 performance of locomotive engines." The Engineer. 
 
 "Mr. Reynolds has opened a new chapter in the literature of the day. This admirable 
 practical treatise, of the practical utility of which we have to speak in terms of warm commendation." 
 Athenceum. 
 
 " Evidently the work of one who knows his subject thoroughly." Railway Service Gazette. 
 " Were the cautions and rules given in the book to become part of the every-day working 
 of our engine-drivers, we might have fewer distressing accidents to deplore." Scotsman. 
 
 STATIONARY ENGINE DRIVING. 
 
 A Practical Manual for Engineers in Charge of Stationary Engines. By 
 MICHAEL REYNOLDS. Fifth Edition, Enlarged. With Plates and Woodcuts. 
 Crown 8vo, cloth 4/6 
 
 " The author is thoroughly acquainted with his subjects, and his advice on the various points 
 treated is clear and practical. ... He has produced a manual which is an exceedingly useful 
 one for the class for whom it is specially intended." Engineering. 
 
 " Our author leaves no stone unturned. He is determined that his readers shall not only 
 know something about the stationary engine, but all about it." Engineer. 
 
 "An engineman who has mastered the contents of Mr. Reynolds's book will require but 
 little actual experience with boilers and engines before he can be trusted to look after them." 
 English Mechanic. 
 
 THE MODEL LOCOMOTIVE ENGINEER, 
 
 Fireman, and Engine-Boy. Comprising a Historical Notice of the Pioneer 
 
 Locomotive Engines and their Inventors. By MICHAEL REYNOLDS. Second 
 
 Edition, with Revised Appendix. With numerous Illustrations, and Portrait 
 
 of George Stephenson. Crown 8vo, cloth. [Just Published. 4/6 
 
 " From the technical knowledge of the author, it will appeal to the railway man of to-day 
 
 more forcibly than anything written by Dr. Smiles. . . . The volume contains information of a 
 
 technical kind, and facts that every driver should be familiar with." English Mechanic. 
 
 " We should be glad to see this book in the possession of everyone in the kingdom who has 
 ever laid, or is to lay, hands on a locomotive engine." Iron. 
 
 CONTINUOUS RAILWAY BRAKES. 
 
 A Practical Treatise on the several Systems in Use in the United Kingdom : 
 
 their Construction and Performance. With copious Illustrations and numerous 
 
 Tables. By MICHAEL REYNOLDS. Large crown 8vo, cloth . . . Q/O 
 
 " A popular explanation of the different brakes. It will be of great assistance in forming 
 
 .public opinion, and will be studied with benefit by those who take an interest in the brake." English 
 
 Mechanic. 
 
 " Written with sufficient technical detail to enable the principal and relative connection of the 
 various parts of each particular brake to be readily grasped." Mechanical World. 
 
 ENGINE-DRIVING LIFE. 
 
 Stirring Adventures and Incidents in the Lives of Locomotive Engine- 
 
 Drivers. By MICHAEL REYNOLDS. Third Edition. Crown 8vo, cloth . 1/6 
 
 " From first to last perfectly fascinating. Wilkie Collins's most thrilling conceptions are 
 
 thrown into the shade by true incidents, endless in their variety, related in every page." North 
 
 British Mail. 
 
 "Anyone who wishes to get a real insight into railway life cannot do better than read 
 ' Engine-Driving Life ' for himself, and if he once takes it up he will find that the author's enthu- 
 siasm and real love of the engine-driving profession will carry him on until he has read every page." 
 Saturday Re-view. 
 
 THE ENGINEMAN'S POCKET COMPANION, 
 
 And Practical Educator for Enginemen, Boiler Attendants, and Mechanics 
 
 By MICHAEL REYNOLDS. With 45 Illustrations and numerous Diagrams. 
 
 Third Edition, Revised. Royal i8mo, strongly bound for pocket wear . 3/6 
 
 " This admirable work is well suited to accomplish its object, being the honest workmanship 
 
 of a competent engineer." Glasgow Herald. 
 
 "A most meritorious work, giving in a succinct and practical form all the information an 
 engine-minder desirous of mastering the scientific principles of his daily calling would require." 
 
 "A boon to those who are striving to become efficient mechanics." Daily Chronicle. 
 
MARINE ENGINEERING, NAVIGATION, &-c. 17 
 
 MARINE ENGINEERING, SHIPBUILDING, 
 NAVIGATION, &c. 
 
 THE NAVAL ARCHITECT'S AND SHIPBUILDER'S 
 
 POCKET-BOOK of Formulae, Rules, and Tables, and Marine Engineer's and 
 Surveyor's Handy Book of Reference. By CLEMENT MACKROW, M.I.N.A. 
 Sixth Edition, Revised, 700 pp., with 300 Illustrations. Fcap., leather. "12/6 
 .SUMMARY OF CONTENTS : SIGNS AND SYMBOLS, DECIMAL FRACTIONS. TRIGONO- 
 METRY. PRACTICAL GEOMETRY. MENSURATION. CENTRES AND MOMENTS OF FIGURES. 
 MOMENTS OF INERTIA AND RADII OF GYRATION. ALGEBRAICAL EXPRESSIONS FOR 
 SIMPSON'S RULES. MECHANICAL PRINCIPLES. CENTRE OF GRAVITY. LAWS OF MOTION. 
 DISPLACEMENT, CENTRE OF BUOYANCY. CENTRE; OF GRAVITY OF SHIP'S HULL. 
 STABILITY CURVES AND METACENTRES. SEA AND SHALLOW-WATER WAVES. ROLLING 
 OF SHIPS. PROPULSION AND RESISTANCE OF VESSELS. SPEED TRIALS. SAILING, 
 CENTRE OF EFFORT. DISTANCES DOWN RIVERS, COAST LINES. STEERING AND 
 RUDDERS OF VESSELS. LAUNCHING CALCULATIONS AND VELOCITIES. WEIGHT OF 
 MATERIAL AND GEAR. GUN PARTICULARS AND WEIGHT. STANDARD GAUGES. 
 RIVETED JOINTS AND RIVETING. STRENGTH AND TESTS OF MATERIALS. BINDING 
 AND SHEARING STRESSES, &c. STRENGTH OF SHAFTING, PILLARS, WHEELS, &c. 
 HYDRAULIC DATA, &c. CONIC SECTIONS, CATENARIAN CURVES. MECHANICAL 
 POWERS, WORK. BOARD OF TRADE REGULATIONS FOR BOILERS AND ENGINES. BOARD 
 OF TRADE REGULATIONS FOR SHIPS. LLOYD'S RULES FOR BOILERS. LLOYD'S WEIGHT 
 OF CHAINS. LLOYD'S SCANTLINGS FOR SHIPS. DATA OF ENGINES AND VESSELS. 
 SHIPS' FITTINGS AND TESTS. SEASONING PRESERVING TIMBER. MEASUREMENT OF 
 TIMBER. ALLOYS, PAINTS, VARNISHES. DATA FOR STOWAGE. ADMIRALTY TRANS- 
 PORT REGULATIONS. RULES FOR HORSE-POWER, SCREW PROPELLERS, &c. PER- 
 CENTAGES FOR BUTT STRAPS, &c. PARTICULARS OF YACHTS. MASTING AND RIGGING 
 VESSELS. DISTANCES OF FOREIGN PORTS. TONNAGE TABLES. VOCABULARY OF 
 FRENCH AND ENGLISH TERMS. ENGLISH WEIGHTS AND MEASURES. FOREIGN 
 WEIGHTS AND MEASURES. DECIMAL EQUIVALENTS. FOREIGN MONEY. DISCOUNT 
 AND WAGES TABLES. USEFUL NUMBERS AND READY RECKONERS. TABLES OF 
 CIRCULAR MEASURES. TABLES OF AREAS OF AND CIRCUMFERENCES OF CIRCLES. 
 TABLES OF AREAS OF SEGMENTS OF CIRCLES. TABLES OF SQUARES AND CUBES AND 
 ROOTS OF NUMBERS. TABLES OF LOGARITHMS OF NUMBERS. TABLES OF HYPER- 
 BOLIC LOGARITHMS. TABLES OF NATURAL SINES, TANGENTS, &c. TABLES OF 
 LOGARITHMIC SINES, TANGENTS, &c. 
 
 " In these days of advanced knowledge a work like this is of the greatest value. It contains 
 a vast amount of information. We unhesitatingly say that it is the most valuable compilation for its 
 specific purpose that has ever been printed. No naval architect, engineer, surveyor, or seaman, 
 wood or iron shipbuilder, can afford to be without this work." Nautical Magazine. 
 
 "Should be used by all who are engaged in the construction or design of vessels. . . . Will 
 be found to contain the most useful tables and formulae required by shipbuilders, carefully collected 
 from the best authorities, and put together in a popular and simple form. The book is one of 
 exceptional merit." Engineer. 
 
 " The professional shipbuilder has now, in a convenient and accessible form, reliable data for 
 solving many of the numerous problems that present themselves in the course of his work." Iron. 
 
 " There is no doubt that a pocket-book of this description must be a necessity in the ship- 
 building trade. . . . The volume contains a mass of useful information clearly expressed and 
 presented in a handy form." Marine Engineer. 
 
 WANNAN'S MARINE ENGINEER'S GUIDE 
 
 To Board of Trade Examinations for Certificates of Competency. Containing 
 all Latest Questions to Date, with Simple, Clear, and Correct Solutions ; 
 Elementary and Verbal Questions and Answers ; complete Set of Drawings 
 with Statements completed. By A. C. WANNAN, C.E., and E. W. I. WANNAN, 
 M.I.M.E. Illustrated with numerous Engravings. Crown 8vo, 370 pages, 
 cloth. [Just Published. 8/6 
 
 WANNAN'S MARINE ENGINEER'S POCKET-BOOK. 
 
 Containing the Latest Board of Trade Rules and Data for Marine Engineers. 
 By A. C. WANNAN. Second Edition, carefully Revised. Square i8mo, with 
 thumb Index, leather. [Just Published. 5/Q 
 
 MARINE ENGINES AND STEAM VESSELS. 
 
 A Treatise on. By ROBERT MURRAY, C.E. Eighth Edition, thoroughly 
 
 Revised, with considerable Additions by the Author and by GEORGE 
 
 CARLISLE, C.E., Senior Surveyor to the Board of Trade, izmo, cloth . 4/6 
 
 "Well adapted to give the young steamship engineer or marine engine and boiler maker a 
 
 general introduction into his practical work." Mechanical World. 
 
 " We feel sure that this thoroughly revised edition will continue to be as popular in the future 
 as it has been in the past, as, for its size, it contains more useful information than any similar 
 treatise." Industries. 
 
 L. B 
 
1 8 CROSBY LOCK WOOD & SON'S CATALOGUE. 
 
 SEA TERMS, PHRASES, AND WORDS 
 
 (Technical Dictionary of) used in the English and French Languages 
 (English-French, French-English). For the Use of Seamen, Engineers, Pilots, 
 Shipbuilders, Shipowners, and Ship-brokers. Compiled by W. PIRRIE, late of 
 the African Steamship Company. Fcap. 8vo, cloth limp. . . . 5/O 
 This volume will be highly appreciated by seamen, engineers, pilots, shipbuilders and ship- 
 l be found wonderfully accurate and complete." Scotsman. 
 
 owners. It will be found wonderfully accurate and complet 
 
 " A very useful dictionary, which has 
 masters, officers and others." Shipping W 
 
 A very useful dictionary, which has long been wanted by French and English engineers, 
 orld, 
 
 ELECTRIC SHIP LIGHTING. 
 
 A Handbook on the Practical Fitting and Running of Ships' Electrical Plant, 
 for the Use of Shipowners and Builders, Marine Electricians and Sea-going 
 Engineers in Charge. By J. W. URQUHART, Author of "Electric Light," 
 " Dynamo Construction," &c. Crown 8vo, cloth ..... 7/6 
 
 MARINE ENGINEER'S POCKET-BOOK. 
 
 Consisting of useful Tables and Formulae. By FRANK PROCTOR, A.I.N.A. 
 
 Third Edition. Royal 321110, leather, gilt edges, with strap . . . 4/O 
 " We recommend it to our readers as going far to supply a long-felt want." Naval Science. 
 " A most useful companion to all marine engineers." United Service Gazette. 
 
 ELEMENTARY ENGINEERING. 
 
 A Manual for Young Marine Engineers and Apprentices. In the Form of 
 
 Questions and Answers on Metals, Alloys, Strength of Materials, Construction 
 
 and Management of Marine Engines and Boilers, Geometry, &c., &c. With 
 
 an Appendix of Useful Tables. By J. S. BREWER. Crown 8vo, cloth . 1/6 
 
 " Contains much valuable information for the class for whom it is intended, especially in the 
 
 chapters on the management of boilers and engines." Nautical Magazine. 
 
 PRACTICAL NAVIGATION. 
 
 Consisting of THE SAILOR'S SEA-BOOK, by JAMES GREENWOOD and W. H. 
 ROSSER ; together with the exquisite Mathematical and Nautical Tables for 
 the Working of the Problems, by HENRY LAW, C.E., and Professor J. R. 
 YOUNG. Illustrated. 12010, strongly half-bound ..... 7/O 
 
 MARINE ENGINEER'S DRAWING -BOOK. 
 
 Adapted to the Requirements of the Board of Trade Examinations. By JOHN 
 LOCKIE, C.E. With 22 Plates, Drawn to Scale. Royal 8vo, cloth . 3/6 
 
 THE ART AND SCIENCE OF SAILMAKING. 
 
 By SAMUEL B. SADLER, Practical Sailmaker, late in the employment of 
 Messrs. Ratsey and Lapthorne, of Cowes and Gosport. With Plates and 
 other Illustrations. Small 410, cloth ....... 1 2/6 
 
 " This extremely practical work gives a complete education in all the branches of the man 
 re, cutting out, roping, seaming, an.' 
 rate text-book and guide." Portsmouth 
 
 facture, cutting out, roping, seaming, and goring. It is copiously illustrated, and will form a first- 
 
 CHAIN CABLES AND CHAINS. 
 
 Comprising Sizes and Curves of Links, Studs, &c., Iron for Cables and Chains. 
 Chain Cable and Chain Making, Forming and Welding Links, Strength of 
 Cables and Chains, Certificates for Cables, Marking Cables, Prices of Chain 
 Cables and Chains, Historical Notes, Acts of Parliament, Statutory Tests, 
 Charges for Testing, List of Manufacturers of Cables, &c., &c. By 
 THOMAS W. TRAILL, F.E.R.N., M.Inst.C.E., Engineer-Surveyor-in-Chief, 
 Board of Trade, Inspector of Chain Cable and Anchor Proving Establishments, 
 and General Superintendent Lloyd's Committee on Proving Establishments. 
 With numerous Tables, Illustrations, and Lithographic Drawings. Folio, 
 
 cloth, bevelled boards 2 2s. 
 
 " It contains a vast amount of valuable information. Nothing seems to be wanting to make it 
 a complete and standard work of reference on the subject." Nautical Magazine. 
 
MINING AND METALLURGY. ig 
 
 MINING AND METALLURGY. 
 
 COLLIERY WORKING AND MANAGEMENT. 
 
 Comprising the Duties of a Colliery Manager, the Oversight and Arrange- 
 ment of Labour and Wages, and the different Systems of Working Coal 
 Seams. By H. F. BULMAN and R. A. S. REDMAYNE. 350 pp., with 
 28 Plates and other Illustrations, including Underground Photographs. 
 Medium Svo, cloth. [Just Published. 1 5/O 
 
 "This is, indeed, an admirable Handbook for Colliery Managers, in fact it is an indispensable 
 adjunct to a Colliery Manager's education, as well as being a most useful and interesting work 
 on the subject for all who in any way have to do with coal mining. The underground photographs 
 are an attractive feature of the work, being very lifelike and necessarily true representations of the 
 scenes they depict." Colliery Guardian. 
 
 " Mr. Bulman and Mr. Redmayne, who are both experienced Colliery Managers of great 
 literary ability, are to be congratulated on having supplied an authoritative work dealing with a side 
 of the subject of coal mining which has hitherto received but scant treatment. The authors 
 elucidate their text by 119 woodcuts and 28 plates, most of the latter being admirable reproductions 
 of photographs taken underground with the aid of the magnesium flash-light. These illustrations 
 are excellent." Nature. 
 
 INFLAMMABLE GAS AND VAPOUR IN THE AIR 
 
 (The Detection and Measurement of). By FRANK CLOWES, D.Sc., Lpnd., 
 F.I.C., Prof, of Chemistry in the University College, Nottingham. With a 
 Chapter on THE DETECTION AND MEASUREMENT OF PETROLEUM VAPOUR 
 by BOVERTON REDWOOD, F.R.S.E., Consulting Adviser to the Corporation 
 of London under the Petroleum Acts. Crown Svo, cloth. 
 
 [Just Published. Net. 5/Q 
 
 " Professor Clowes has given us a volume on a subject of much industrial importance . . . 
 Those interested in these matters may be recommended to study this book, which is easy of compre- 
 hension and contains many good things." The Engineer. 
 
 " A convenient summary of the work on which Professor Clowes has been engaged for some 
 considerable time. . . . It is hardly necessary to say that any work on these subjects with these 
 names on the title-page must be a valuable one, and one that no mining engineer certainly no coal 
 miner can afford to ignore or to leave unread." Mining "Journal. 
 
 MACHINERY FOR METALLIFEROUS MINES. 
 
 A Practical Treatise for Mining Engineers, Metallurgists, and Managers of 
 
 Mines. By E. HENRY DAVIES, M.E., F.G.S. Crown Svo, 580 pp., with 
 
 upwards of 300 Illustrations, cloth. [Just Published. "| 2/6 
 
 " Mr. Davies, in this handsome volume, has done the advanced student and the manager of 
 
 mines good service. Almost every kind of machinery in actual use is carefully described, and the 
 
 woodcuts and plates are good." Athenaiim. 
 
 " From cover to cover the work exhibits all the same characteristics which excite the conn- 
 dence and attract the attention of the student as he peruses the first page. The work may safely 
 be recommended. By its publication the literature connected with the industry will be enriched 
 and the reputation of its author enhanced." Mining Journal. 
 
 METALLIFEROUS MINERALS AND MINING. 
 
 By D. C. DAVIES, F.G.S. , Mining Engineer, &c., Author of "A Treatise on 
 Slate and Slate Quarrying." Fifth Edition, thoroughly Revised and much 
 Enlarged by his Son, E. HENRY DAVIES, M.E., F.G.S. With about 150 
 
 Illustrations. Crown Svo, cloth . ~\ 2/6 
 
 " Neither the practical miner nor the general reader, interested in mines, can have a bette. 
 book for his companion and his guide." Mining- Journal. 
 
 " We are doing our readers a service in calling their attention to this valuable work." 
 Mining World. 
 
 " As a history of the present state of mining throughout the world this book has a real value, 
 and it supplies an actual want." Athenaum. 
 
 EARTHY AND OTHER MINERALS AND MINING. 
 
 By D. C. DAVIES, F.G.S., Author of " Metalliferous Minerals," &c. Third 
 Edition, Revised and Enlarged by his Son, E. HENRY DAVIES, M.E., F.G.S. 
 
 With about zoo Illustrations. Crown Svo, cloth "| 2/6 
 
 " We do not remember to have met with any English work on mining matters that contains 
 the same amount of information packed in equally convenient form." Academy. 
 
 " We should be inclined to rank it as among the very best of the handy technical and trades 
 manuals which have recently appeared." British Quarterly Review. 
 
CROSBY LOCK WOOD 6- SON'S CATALOGUE. 
 
 BRITISH MINING. 
 
 A Treatise on the History, Discovery, Practical Development, and Future 
 
 Prospects of Metalliferous Mines in the United Kingdom. By ROBERT 
 
 HUNT, F.R.S., late Keeper of Mining Records. Upwards of 950 pp., with 
 
 230 Illustrations. Second Edition, Revised. Super-royal 8vo, cloth 2 2s. 
 
 " The book is a treasure-house of statistical information on mining subjects, and we know of 
 
 no other work embodying so great a mass of matter of this kind. Were this the only merit of 
 
 Mr. Hunt's volume it would be sufficient to render it indispensable in the library of every one 
 
 nterested in the development of the mining and metallurgical industries of this country." 
 
 A thenaum. 
 
 " A mass of information not elsewhere available, and of the greatest value to those who may 
 be interested in our great mineral industries." Engineer. 
 
 MINE DRAINAGE. 
 
 A Complete and Practical Treatise on Direct-Acting Underground Steam 
 Pumping Machinery, with a Description of a large number of the best known 
 Engines, their General Utility and the Special Sphere of their Action, the 
 Mode of their Application, and their merits compared with other forms of 
 Pumping Machinery. By STEPHEN MICHELL. 8vo, cloth . . 1 5/O 
 " Will be highly esteemed by colliery owners and lessees, mining engineers, and students 
 
 generally who require to be acquainted with the best means of securing the drainage of mines. 
 
 It is a most valuable work, and stands almost alone in the literature of steam pumping machinery." 
 
 Colliery Guardian. 
 
 " Much valuable information is given, so that the book is thoroughly worthy of an extensive 
 
 circulation amongst practical men and purchasers of machinery." Mining- Journal. 
 
 THE PROSPECTOR'S HANDBOOK. 
 
 A Guide for the Prospector and Traveller in search of Metal-Bearing or other 
 
 Valuable Minerals. By J. W. ANDERSON, M.A. (Camb.), F.R.G.S., Author 
 
 of "Fiji and New Caledonia." Seventh Edition, thoroughly Revised and 
 
 much Enlarged. Small crown 8vo, cloth, 3/6 ! or, leather, pocket-book form, 
 
 with tuck. [Just Published. 4/6 
 
 " Will supply a much-felt want, especially among Colonists, in whose way are so often thrown 
 
 many mineralogical specimens the value of which it is difficult to determine." Engineer. 
 
 " How to find commercial minerals, and how to identify them when they are found, are the 
 leading points to which attention is directed. The author has managed to pack as much practical 
 detail into his pages as would supply material for a book three times its size." Mining Journal. 
 
 NOTES AND FORMUL/E FOR MINING STUDENTS. 
 
 By JOHN HERMAN MERIVALE, M.A., Late Professor of Mining in the Durham 
 College of Science, Newcastle-upon-Tyne. Fourth Edition, Revised and 
 Enlarged. By H. F. BULMAN, A.M.Inst.C.E. Small crown 8vo, cloth. 
 
 [Just Published. 2/6 
 
 " The author has done his work in a creditable manner, and has produced a book that will 
 be of service to students and those who are practically engaged in mining operations." Engineer. 
 
 THE MINER'S HANDBOOK. 
 
 A Handy Book of Reference on the subjects of Mineral Deposits, Mining 
 
 Operations, Ore Dressing, &c. For the Use of Students and others interested 
 
 in Mining Matters. By JOHN MILNE, F.R.S., Professor of Mining in the 
 
 Imperial University of Japan. Revised Edition. Fcap. 8vo, leather . 7/6 
 
 " Professor Milne's handbook is sure to be received with favour by all connected with 
 
 mining, and will be extremely popular among students." Athenceum. 
 
 POCKET=BOOK FOR MINERS AND METALLURGISTS. 
 
 Comprising Rules, Formulae, Tables, and Notes for Use in Field and Office 
 Work. By F. DANVERS POWER, F.G.S., M.E. Fcap. 8vo, leather . 9/Q 
 ' This excellent book is an admirable example of its kind, and ought to find a large sale 
 atnongst English-speaking prospectors and mining engineers." Engineering. 
 
 MINERAL SURVEYOR AND VALUER'S GUIDE. 
 
 Comprising a Treatise on Improved Mining Surveying and the Valuation of 
 Mining Properties, with New Traverse Tables. By WM. LINTERN. Fourth 
 Edition, Enlarged, izmo, cloth 3/6 
 
MINING AND METALLURGY. 21 
 
 THE COLLIERY MANAGER'S HANDBOOK. 
 
 A Comprehensive Treatise on the Laying-out and Working of Collieries, 
 Designed as a Book of Reference for Colliery Managers, and for the Use of Coal 
 Mining Students preparing for First-class Certificates. By CALEB PAMELY, 
 Mining Engineer and Surveyor ; Member of the North of England Institute of 
 Mining and Mechanical Engineers ; and Member of the South Wales Institute 
 of Mining Engineers. With 700 Plans, Diagrams, and other Illustrations. 
 Fourth Edition, Revised and Enlarged, medium 8vo, over 900 pp. 
 Strongly bound 1 5s. 
 
 SUMMARY OF CONTENTS : GEOLOGY. SEARCH FOR COAL. MINERAL LEASES 
 AND OTHER HOLDINGS. SHAFT SINKING. FITTING UP THE SHAFT AND SURFACE 
 ARRANGEMENTS. STEAM BOILERS AND THEIR FITTINGS. TIMBERING AND WALLING. 
 NARROW WORK AND METHODS OF WORKING. UNDERGROUND CONVEYANCE. 
 DRAINAGE. THE GASES MET WITH IN MINES; VENTILATION. ON THE FRICTION OK 
 AIR IN MINES. THE PRIESTMAN OIL ENGINE; PETROLEUM AND NATURAL GAS. 
 SURVEYING AND PLANNING. SAFETY LAMPS AND FIREDAMP DETECTORS. SUNDRY 
 AND INCIDENTAL OPERATIONS AND APPLIANCES. COLLIERY EXPLOSIONS. MISCEL- 
 LANEOUS QUESTIONS AND ANSWERS. Appendix: SUMMARY OF REPORT OF H.M. 
 COMMISSIONERS ON ACCIDENTS IN MINES. 
 
 " Mr. Pamely has not only given us a comprehensive reference book of a very high order, 
 suitable to the requirements of mining engineers and colliery managers, but has also provided 
 mining students with a class-book that is as interesting as it is instructive." Colliery Manager. 
 
 " Mr. Pamely 's work is eminently suited to the purpose for which it is intended, being clear, 
 interesting, exhaustive, rich in detail, and up to date, giving descriptions of the latest machines in 
 every department. A mining engineer could scarcely go wrong who followed this work." Colliery 
 Guardian. 
 
 "This is the most complete 'all-round' work on coal-mining published in the English 
 language. . . . No library of coal-mining books is complete without it." Colliery Engineer 
 (Scranton, Pa., U.S.A.). 
 
 COAL & IRON INDUSTRIES of the UNITED KINGDOM. 
 
 Comprising a Description of the Coal Fields, and of the Principal Seams of 
 Coal, with Returns of their Produce and its Distribution, and Analyses of 
 Special Varieties. Also, an Account of the Occurrence of Iron Ores in Veins or 
 Seams ; Analyses of each Variety ; and a History of the Rise and Progress of 
 Pig Iron Manufacture. By RICHARD MEADE. 8vo, cloth . . 1 8s. 
 "Of this book we may unreservedly say that it is the best of its class which we have ever 
 
 met. ... A book of reference which no one engaged in the iron or coal trades should omit from 
 
 his library." Iron and Coal Trades Review. 
 
 COAL AND COAL MINING. 
 
 By the late Sir WARINGTON W. SMYTH, M.A., F.R.S., &c., Chief Inspector 
 of the Mines of the Crown. Seventh Edition, Revised and Enlarged. With 
 
 numerous Illustrations, izmo, cloth 3/6 
 
 " As an outline is given of every known coal-field in this and other countries, as well as of the 
 
 principal methods of working, the book will doubtless interest a very large number of readers." 
 
 Mining Journal. 
 
 ASBESTOS AND ASBESTIC. 
 
 Their Properties, Occurrence, and Use. By ROBERT H. JONES, F.S.A., 
 Mineralogist, Hon. Mem. Asbestos Club, Black Lake, Canada. With Ten 
 Collotype Plates and other Illustrations. Demy 8vo, cloth. [Just Published. 1 6/O 
 " An interesting and invaluable work." Colliery Guardian. 
 
 SUBTERRANEOUS SURVEYING 
 
 (Elementary and Practical Treatise on), with and without the Magnetic Needle. 
 By THOMAS FENWICK, Surveyor of Mines, and THOMAS BAKER, C.E. Illus- 
 trated, larno, cloth 2/6 
 
 GRANITES AND OUR GRANITE INDUSTRIES. 
 
 By GEORGE F. HARRIS, F.G.S., Membre de la Socie'te' Beige de Geologic, 
 Lecturer on Economic Geology at the Birkbeck Institution, &c. With Illus- 
 trations. Crown 8vo, cloth . . . 2/6 
 
 " A clearly and well-written manual for persons engaged or interested in the granite industry." 
 Scotsman. 
 
22 CROSBY LOCK WOOD S> SON'S CATALOGUE. 
 THE METALLURGY OF GOLD. 
 
 A Practical Treatise on the Metallurgical Treatment of Gold-bearing Ores. 
 Including the Processes of Concentration, Chlorination, and Extraction by 
 Cyanide, and the Assaying, Melting, and Refining of Gold. By M. EISSLER, 
 Mining Engineer and Metallurgical Chemist, formerly Assistant Assayer of the 
 U.S. Mint, San Francisco. Fourth Edition, Enlarged. With about 250 Illus- 
 trations and numerous Folding Plates and Working Drawings. Large crown 
 8vo, cloth. [Just Published. 1 6/6 
 
 " This book thoroughly deserves its title of a ' Practical Treatise.' The whole process of gold 
 milling, from the breaking of the quartz to the assay of the bullion, is described in clear and orderly 
 narrative and with much, but not too much, fulness of detail." Saturday Revie-w. 
 
 " The work is a storehouse of information and valuable data, and we strongly recommend it 
 to all professional men engaged in the gold-mining industry." Mining Journal. 
 
 THE CYANIDE PROCESS OF GOLD EXTRACTION. 
 
 Including its Practical Application on the Witwatersrand Gold Fields in South 
 Africa. By M. EISSLER, M.E., Author of "The Metallurgy of Gold," &c. 
 With Diagrams and Working Drawings. Second Edition, Revised and En- 
 larged. 8vo, cloth. [Just Published. 7/6 
 
 "This book is just what was needed to acquaint mining men with the actual working of a 
 process which is not only the most popular, but is, as a general rule, the most successful for the 
 extraction of gold from tailings." Mining Journal. 
 
 " The work will prove invaluable to all interested in gold mining, whether metallurgists or as 
 investors." Chemical Ne-ws. 
 
 THE METALLURGY OF SILVER. 
 
 A Practical Treatise on the Amalgamation, Roasting, and Lixiviation of Silver 
 Ores. Including the Assaying, Melting, and Refining of Silver Bullion. By 
 M. EISSLER, Author of "The Metallurgy of Gold," &c. Third Edition. 
 Crown 8vo, cloth 1 O/6 
 
 " A practical treatise, and a technical work which we are convinced will supply a long-felt 
 want amongst practical men, and at the same time be of value to students and others indirectly 
 connected with the industries." Mining Journal. 
 
 " From first to last the book is thoroughly sound and reliable." Colliery Guardian. 
 
 " For chemists, practical miners, assayers, and investors alike we do not know of any work 
 on the subject so handy and yet so comprehensive." Glasgow Herald. 
 
 THE METALLURGY OF ARGENTIFEROUS LEAD. 
 
 A Practical Treatise on the Smelting of Silver-Lead Ores and the Refining of 
 Lead Bullion. Including Reports on various Smelting Establishments and 
 Descriptions of Modern Smelting Furnaces and Plants in Europe and America. 
 By M. EISSLER, M.E., Author of " The Metallurgy of Gold," &c. Crown 8vo, 
 400 pp., with 183 Illustrations, cloth 12/6 
 
 " The numerous metallurgical processes, which are fully and extensively treated of, embrace 
 all the stages experienced in the passage of the lead from the various natural states to its issue from 
 the refinery as an article of commerce." Practical Engineer. 
 
 " The present volume fully maintains the reputation of the author. Those who wish to obtain 
 a thorough insight into the present state of this industry cannot do better than read this volume, and 
 all mining engineers cannot fail to find many useful hints and suggestions in it." Industries. 
 
 METALLURGY OF IRON. 
 
 By H. BAUERMAN, F.G.S., A.R.S.M. Sixth Edition, Revised and Enlarged. 
 i2mo, cloth 5/O 
 
 THE IRON ORES of GREAT BRITAIN and IRELAND. 
 
 Their Mode of Occurrence, Age and Origin, and the Methods of Searching for 
 and Working Them. With a Notice of some of the Iron Ores of Spain. By 
 J. D. KENDALL, F.G.S., Mining Engineer. Crown 8vo, cloth . . 1 6/O 
 
 "The author has a thorough practical knowledge of his subject, and has supplemented a 
 careful study of the available literature by unpublished information derived from his own observa- 
 tions The result is a very useful volume, which cannot fail to be of value to all interested in the 
 iron industry of the country. "Industries. 
 
ELECTRICITY, ELECTRICAL ENGINEERING, &>c. 23 
 
 ELECTRICITY, ELECTRICAL 
 ENGINEERING, &c. 
 
 SUBMARINE TELEGRAPHS. 
 
 Their History, Construction, and Working. Founded in part on WUNSCHEN- 
 DORFF'S " Traite de Telegraphic Sous-Marine," and Compiled from Authorita- 
 tive and Exclusive Sources. By CHARLES BRIGHT, F.R.S.E. Super-royal 
 8vo, about 780 pp., fully Illustrated, including Maps and Folding Plates. 
 
 [Just Published. Net. 3 3s. 
 
 " There are few, if any, persons more fitted to write a treatise on submarine telegraphy than 
 Mr. Charles Bright. The author has done his work admirably, and has written in a way which will 
 appeal as much to the layman as to the engineer. This admirable volume must, for many years to 
 come, hold the position of the English classic on submarine telegraphy." Engineer. 
 
 " This book is full of information. It makes a book of reference which should be in every 
 engineer's library." Nature. 
 
 " Mr. Bright's interestingly written and admirably illustrated book will meet with a welcome 
 reception from cable men." Electrician. 
 
 " The author deals with his subject from all points of view political and strategical as well as 
 scientific. The work will be of interest, not only to men of science, but to the general public. We 
 can strongly recommend it." Athentzum. 
 
 " The work contains a great store of technical information concerning the making and work- 
 ing of submarine telegraphs. In bringing together the most valuable results relating to the evolu- 
 tion of the telegraph, the author has rendered a service that will be very widely appreciated." 
 Morning Post. 
 
 THE ELECTRICAL ENGINEER'S POCKET-BOOK. 
 
 Consisting of Modern Rules, Formulae, Tables, and Data. By H. R. KEMPE, 
 M.Inst.E.E., A.M.Inst.C.E., Technical Officer Postal Telegraphs, Author of 
 "A Handbook of Electrical Testing," "The Engineer's Year-Book," &c. 
 Second Edition, thoroughly Revised, with Additions. With numerous Illus- 
 trations. Royal 321110, oblong, leather S/O 
 
 " It is the best book of its kind." Electrical Engineer. 
 
 " The Electrical Engineer's Pocket-Book is a good one." Electrician. 
 
 " Strongly recommended to those engaged in the electrical industries." Electrical Review. 
 
 ELECTRIC LIGHT FITTING. 
 
 A Handbook for Working Electrical Engineers, embodying Practical Notes on 
 Installation Management. By J. W. URQUHART, Electrician, Author of 
 "Electric Light," &c. With numerous Illustrations. Third Edition, 
 Revised, with Additions. Crown 8vo, cloth. [Just Published. 5/Q 
 
 "This volume deals with what may be termed the mechanics of electric lighting, and is 
 
 addressed to men who are already engaged in the work, or are training for it. The work traverses 
 
 a great deal of ground, and may be read as a sequel to the same author's useful work on ' Electric 
 
 Light. ' " Electrician. 
 
 "Eminently practical and useful. . . . Ought to be in the hands of every one in charge of an 
 
 electric light plant." Electrical Engineer. 
 
 ELECTRIC LIGHT. 
 
 Its Production and Use, Embodying Plain Directions for the Treatment of 
 Dynamo-Electric Machines, Batteries, Accumulators, and Electric Lamps. 
 By J. W. URQUHART, C.E. Sixth Edition, Revised, with Additions and 145 
 Illustrations. Crown 8vo, cloth. [Just Published. 7/6 
 
 " The whole ground of electric lighting is more or less covered and explained in a very clear 
 and concise manner." Electrical Review. 
 
 " A vade-mecum of the salient facts connected with the science of electric lighting." 
 
 "You cannot for your purpose have a better book than 'Electric Light' by Urquhart." 
 Engineer. 
 
 DYNAMO CONSTRUCTION. 
 
 A Practical Handbook for the Use of Engineer-Constructors and Electricians- 
 in -Charge. Embracing Framework Building, Field Magnet and Armature 
 Winding and Grouping, Compounding, &c. With Examples of leading 
 English, American, and Continental Dynamos and Motors. By J. W. 
 URQUHART, Author of " Electric Light," &c. Second Edition, Enlarged. 
 
 With 114 Illustrations. Crown 8vo, cloth 7/6 
 
 " Mr. Urquhart's book is the first one which deals with these matters in such a way that the 
 engineering student can understand them. The book is very readable, and the author leads his 
 readers up to difficult subjects by reasonably simple tests." Engineering Review. 
 " A book for which a demand has long existed." Mechanical World. 
 
24 CROSBY LOCK WOOD 6- SON'S CATALOGUE. 
 
 THE MANAGEMENT OF DYNAMOS. 
 
 A Handy Book of Theory and Practice for the Use of Mechanics, Engineers, 
 Students, and others in Charge of Dynamos. By G. W. LUMMIS PATERSON. 
 
 With numerous Illustrations. Crown 8vo, cloth 3/6 
 
 " An example which deserves to be taken as a model by other authors. The subject is treated 
 in a manner which any intelligent man who is fit to be entrusted with charge of an engine should 
 be able to understand. It is a useful book to all who make, tend, or employ electric machinery." 
 Architect. 
 
 THE STANDARD ELECTRICAL DICTIONARY. 
 
 A Popular Encyclopaedia of Words and Terms Used in the Practice of Electrical 
 Engineering. By T. O'CoNOR SLOANE, A.M., Ph.D. Second Edition, 
 with Appendix to date. Crown 8vo, 680 pp., 390 Illustrations, cloth. 
 
 [Just Published. 7/6 
 
 " The work has many attractive features in it, and is, beyond doubt, a well put together and 
 useful publication. The amount of ground covered may be gathered from the fact that in the index 
 about 5,600 references will be found." Electrical Review. 
 
 ELECTRIC SHIP-LIGHTING. 
 
 A Handbook on the Practical Fitting and Running of Ships' Electrical Plant. 
 For the Use of Shipowners and Builders, Marine Electricians, and Seagoing 
 Engineers-in-Charge. By J. W. URQUHART, C.E. With 88 Illustrations, 
 
 Crown 8vo, cloth ; 7/6 
 
 "The subject of ship electric lighting is one of vast importance, and Mr. Urquhart is to be 
 
 highly complimented for placing such a valuable work at the service of marine electricians." The 
 
 Steamship. 
 
 ELECTRIC LIGHT FOR COUNTRY HOUSES. 
 
 A Practical Handbook on the Erection and Running of Small Installations, 
 
 with Particulars of the Cost of Plant and Working. By J. H. KNIGHT. 
 
 Second Edition, Revised. Crown 8vo, wrapper. [Just Published. 1 /Q 
 
 " The book contains excellent advice and many practical hints for the help of those who wish 
 
 to light their own houses." Building Ne-ws. 
 
 ELEMENTARY PRINCIPLES OF ELECTRIC LIGHTING. 
 
 By ALAN A. CAMPBELL SWINTON, Associate I.'E.E. Third Edition, Enlarged 
 and Revised. With 16 Illustrations. Crown 8vo,. cloth . . . .1/6 
 " Any one who desires a short and thoroughly clear exposition of the elementary principles of 
 electric lighting cannot do better than read this little v/or\a."Brad/ord Observer. 
 
 DYNAMIC ELECTRICITY AND MAGNETISM. 
 
 By PHILIP ATKINSON, A.M., Ph.D., Author of "Elements of Static 
 Electricity," &c. Crown 8vo, 417 pp., with 120 Illustrations, cloth . 1 O/6 
 
 THE ELECTRIC TRANSFORMATION OF POWER. 
 
 With its Application by the Electric Motor, including Electric Railway 
 Construction. By P. ATKINSON, A.M., Ph.D. With 96 Illustrations. 
 Crown 8vo, cloth 7/6 
 
 HOW TO MAKE A DYNAMO. 
 
 A Practical Treatise for Amateurs. Containing numerous Illustrations and 
 Detailed Instructions for Constructing a Small Dynamo to Produce the 
 Electric Light. By ALFRED CROFTS. Fifth Edition, Revised and Enlarged. 
 Crown 8vo, cloth. [Just Published. 2/O 
 
 " The instructions given in this unpretentious little book are sufficiently clear and explicit to 
 
 enable any amateur mechanic possessed of average skill and the usual tools to be found in an 
 
 amateur's workshop to build a practical dynamo machine." Electrician. 
 
 THE STUDENT'S TEXT=BOOK OF ELECTRICITY. 
 
 By H. M. NOAD, F.R.S. Cheaper Edition. 650 pp., with 470 Illustrations. 
 Crown 8vo, cloth 9/O 
 
ARCHITECTURE, BUILDING, &>c. 25 
 
 ARCHITECTURE, BUILDING, &c. 
 
 PRACTICAL BUILDING CONSTRUCTION. 
 
 A Handbook for Students Preparing for Examinations, and a Book of 
 
 Reference for Persons Engaged in Building. By JOHN PARNELL ALLEN, 
 
 Surveyor, Lecturer on Building Construction at the Durham College of 
 
 Science, Newcastle-on-Tyne. Second Edition, Revised and Enlarged. 
 
 Medium 8vo, 450 pp., with 1,000 Illustrations, cloth. [Just Published. 7/6 
 
 " The most complete exposition of building construction we have seen. It contains all that is 
 
 necessary to prepare students for the various examinations in building construction/' Building 
 
 News. 
 
 " The author depends nearly as much on his diagrams as on his type. The pages suggest 
 the hand of a man of experience in building operations and the volume must be a blessing to 
 many teachers as well as to students." The Architect. 
 
 "The work is sure to prove a formidable rival to great and small competitors alike, and 
 bids fair to take a permanent place as a favourite student's text-book. The large number of illus- 
 trations deserve particular mention for the great merit they possess for purposes of reference in 
 exactly corresponding to convenient scales." Journal of the Royal Institute of British Architects. 
 
 PRACTICAL MASONRY. 
 
 A Guide to the Art of Stone Cutting. Comprising the Construction, Setting 
 Out, and Working of Stairs, Circular Work, Arches, Niches, Domes, Penden- 
 tives, Vaults, Tracery Windows, &c., &c. For the Use of Students, Masons, 
 and other Workmen. By WILLIAM R. PURCHASE, Building Inspector to the 
 Borough of Hove. Second Edition, with Glossary of Terms. Royal 8vo, 142 pp., 
 with 52 Lithographic Plates, comprising nearly 400 separate Diagrams, 
 
 cloth 7/6 
 
 " Mr. Purchase's ' Practical Masonry ' will undoubtedly be found useful to all interested in 
 this important subject, whether theoretically or practically. Most of the examples given are from 
 actual work carried out, the diagrams being carefully drawn. The book is a practical treatise on 
 the subject, the author himself having commenced as an operative mason, and afterwards acted as 
 foreman mason on many large and important buildings prior to the attainment of his present 
 position. It should be found of general utility to architectural students and others, as well as to 
 those to whom it is specially addressed." Journal of the Royal Institute of British Architects. 
 
 CONCRETE: ITS NATURE AND USES. 
 
 A Book for Architects, Builders, Contractors, and Clerks of Works. By 
 GEORGE L. SUTCLIFFE, A.R.I.B.A. 350 pp., with numerous Illustrations. 
 Crown 8vo, cloth 7/6 
 
 " The author treats a difficult subject in a lucid manner. The manual fills a long-felt gap. 
 It is careful and exhaustive ; equally useful as a student's guide and an architect's book of 
 reference." Journal of the Royal Institute of British Architects. 
 
 " There is room for this new book, which will probably be for some time the standard work 
 on the subject for a builder's purpose." Glasgow Herald. 
 
 THE MECHANICS OF ARCHITECTURE. 
 
 A Treatise on Applied Mechanics, especially Adapted to the Use of Architects. 
 
 By E. W. TARN, M.A., Author of "The Science of Building," &c. Second 
 
 Edition, Enlarged. Illustrated with 125 Diagrams. Crown 8vo, cloth 7/6 
 
 " The book is a very useful and helpful manual of architectural mechanics, and really contains 
 
 sufficient to enable a careful and painstaking student to grasp the principles bearing upon the 
 
 majority of building problems. . . . Mr. Tarn has added, by this volume, to the debt of 
 
 gratitude which is owing to him by architectural students for the many valuable works which he has 
 
 produced for their use." The Builder. 
 
 LOCKWOOD'S BUILDER'S PRICE BOOK for 1899. 
 
 A Comprehensive Handbook of the Latest Prices and Data for Builders, 
 Architects, Engineers, and Contractors. Re-constructed, Re-written, and 
 Greatly Enlarged. By FRANCIS T. W. MILLER. 800 closely-printed pages, 
 
 crown 8vo, cloth 4/O 
 
 "This book is a very useful one, and should find a place in every English office connected 
 with the building and engineering professions." Industries. 
 "An excellent book of reference." Architect. 
 
 " In its new and revised form this Price Book is what a work of this kind should be compre- 
 hensive, reliable, well arranged, legible, and well bound." British Architect. 
 
 THE DECORATIVE PART OF CIVIL ARCHITECTURE. 
 
 By Sir WILLIAM CHAMBERS, F.R.S. With Portrait, Illustrations, Notes, and 
 an EXAMINATION OF GRECIAN ARCHITECTURE, by JOSEPH GWILT, F.S.A. 
 Revised and Edited by W. H. LEEDS. 66 Plates, 410, cloth . . 2 "I/O 
 
26 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 
 A HANDY BOOK OF VILLA ARCHITECTURE. 
 
 Being a Series of Designs for Villa Residences in various Styles. With 
 Outline Specifications and Estimates. By C. WICKES, Architect, Author of 
 "The Spires and Towers of England," &c. 61 Plates, 410, half-morocco, gilt 
 edges 1 11s. 60. 
 
 "The whole of the designs bear evidence of their being the work of an artistic architect, and 
 they will prove very valuable and suggestive." Building News, 
 
 THE ARCHITECT'S GUIDE. 
 
 Being a Text-book of Useful Information for Architects, Engineers, Surveyors, 
 Contractors, Clerks of Works, &c., &c. By FREDERICK ROGERS, Architect. 
 
 Third Edition. Crown 8vo, cloth 3/6 
 
 "As a text-book of useful information for architects, engineers, surveyors, &c., it would be 
 hard to find a handier or more complete little volume." Standard. 
 
 ARCHITECTURAL PERSPECTIVE. 
 
 The whole Course and Operations of the Draughtsman in Drawing a Large 
 
 House in Linear Perspective. Illustrated by 43 Folding Plates. By F. O. 
 
 FERGUSON. Second Edition, Enlarged. 8vo, boards .... 3/6 
 
 " It is the most intelligible of the treatises on this ill-treated subject that I have met with." 
 
 E. INGRESS BELL, ESQ., in the R.I.B.A. Journal. 
 
 PRACTICAL RULES ON DRAWING. 
 
 For the Operative Builder and Young Student in Architecture. By GEORGE 
 PYNE. 74 Plates, 4to, boards 7/6 
 
 MEASURING AND VALUING ARTIFICER'S WORK 
 
 (The Student's Guide to the Practice of)- Containing Directions for taking 
 Dimensions, Abstracting the same, and bringing the Quantities into Bill, with 
 Tables of Constants for Valuation of Labour, and for the Calculation of Areas 
 and Solidities. Originally edited by E. DOBSON, Architect. With Additions 
 by E. W. TARN, M.A. Sixth Edition. With 8 Plates and 63 Woodcuts. 
 
 Crown 8vo, cloth 7/6 
 
 " This edition will be found the most complete treatise on the principles of measuring and 
 valuing artificer's work that has yet been published." Building News. 
 
 TECHNICAL GUIDE, MEASURER, AND ESTIMATOR. 
 
 For Builders and Surveyors. Containing Technical Directions for Measuring 
 Work in all the Building Trades, Complete Specifications for Houses, Roads, 
 and Drains, and an Easy Method of Estimating the parts of a Building 
 collectively. By A. C. BEATON. Eighth Edition. Waistcoat-pocket size, 
 
 gilt edges 1/6 
 
 "No builder, architect, surveyor, or valuer should be without his 'Beaton.'" Building 
 Ne-ws. 
 
 CONSTRUCTIONAL IRON AND STEEL WORK. 
 
 As Applied to Public, Private, and Domestic Buildings. A Practical Treatise 
 for Architects, Students, and Builders. By F. CAMPIN. Crown 8vo, cloth. 
 
 [Just Published. 3/6 
 
 " Any one who wants a book on ironwork, as employed in buildings for stanchions, columns, 
 and beams, will find the present volume to be suitable. The author has had long and varied 
 experience in designing this class of work. The illustrations have the character of working 
 drawings. This practical book may be counted a most valuable work." British. Architect. 
 
 SPECIFICATIONS FOR PRACTICAL ARCHITECTURE. 
 
 A Guide to the Architect, Engineer, Surveyor, and Builder. With an Essay 
 on the Structure and Science of Modern Buildings. Upon the Basis of the 
 Work by ALFRED BARTHOLOMEW, thoroughly Revised, Corrected, and greatly 
 added to by FREDERICK ROGERS, Architect. Third Edition, Revised. 8vo, 
 
 cloth 15/O 
 
 "The work is too well known to need any recommendation from us. It is one of the books 
 with which every young architect must be equipped." Architect. 
 
 THE HOUSE-OWNER'S ESTIMATOR. 
 
 Or, What will it Cost to Build, Alter, or Repair ? A Price Book for Un- 
 professional People as well as the Architectural Surveyor and Builder. By 
 J. D. SIMON. Edited by F. T. W. MILLER, A.R.I. B.A. Fourth Edition. 
 
 Crown 8vo, cloth 3/6 
 
 " In two years it will repay its cost a hundred times over." Field. 
 
SANITATION AND WATER SUPPLY. 27 
 
 SANITATION AND WATER SUPPLY. 
 
 THE PURIFICATION OF SEWAGE. 
 
 Being a Brief Account of the Scientific Principles of Sewage Purification, and 
 
 their Practical Application. By SIDNEY BARWISE, M.D. (Lond.), M.R.C.S., 
 
 D.P.H. (Camb.), Fellow of the Sanitary Institute, Medical Officer of Health 
 
 to the Derbyshire County Council. Crown 8vo, cloth. [Just published. 5 JO 
 
 " ' What process shall we adopt to purify our sewage ? ' This question has rarely been treated 
 
 from so many points of view in one book. This volume teems with practical hints, which show the 
 
 intimate knowledge the author has of his subject.' The Engineer. 
 
 "We know of no book of the same size which gives so complete and accurate an account of 
 the principles of sewage purification." The Builder. 
 
 WATER AND ITS PURIFICATION. 
 
 A Handbook for the Use of Local Authorities, Sanitary Officers, and others 
 
 interested in Water Supply. By S. RIDEAL, D.Sc. Lond., F.I.C. With 
 
 numerous Illustrations and Tables. Crown 8vo, cloth. [Just Published. 7/6 
 
 "Dr. Rideal's book is both interesting and accurate, and contains a most useful resume of 
 
 the latest knowledge upon the subject of which it treats. It ought to be of great service to all who 
 
 are connected with the supply of water for domestic or manufacturing purposes." The Engineer. 
 
 " Dealing as clearly as it does with the various ramifications of such an important subject as 
 water and its purification it may be warmly recommended. Local authorities and all engaged in 
 sanitary affairs, and others interested in water supply, will read its pages with profit." Lancet. 
 
 RURAL WATER SUPPLY. 
 
 A Practical Handbook on the Supply of Water and Construction of Water- 
 works for Small Country Districts. By ALLAN GREENWELL, A.M.I.C.E., 
 andW. T. CURRY, A.M.I.C.E. Revised Edition. Crown 8vo, cloth 5/O 
 "We conscientiously recommend it as a very useful book for those concerned in obtaining 
 water for small districts, giving a great deal of practical information in a small compass." Builder. 
 
 THE WATER SUPPLY OF CITIES AND TOWNS. 
 
 By WILLIAM HUMBER, A.M. Inst. C.E., and M.Inst. M.E. Imp. 410, half- 
 bound morocco. (See page 10.) ...... Net 6 6s. 
 
 THE WATER SUPPLY OF TOWNS AND THE CON- 
 STRUCTION OF WATER-WORKS. 
 
 By PROFESSOR W. K. BURTON, A.M. Inst. C.E. Second Edition, Revised 
 and Extended. Royal 8vo, cloth. (See page 9) 25/O 
 
 THE HEALTH OFFICER'S POCKET=BOOK. 
 
 A Guide to Sanitary Practice and Law. For Medical Officers of Health, 
 
 Sanitary Inspectors, Members of Sanitary Authorities, &c. By EDWARD 
 
 F. WILLOUGHBY, M.D. (Lond.), &c. Fcap. 8vo, cloth .... 7/6 
 
 " A mine of condensed information of a pertinent and useful kind on the various subjects of 
 
 which it treats. The matter seems to have been carefully compiled and arranged for facility of 
 
 reference, and it is well illustrated by diagrams and woodcuts. The different subjects are 
 
 succinctly but fully and scientifically dealt with." The Lancet. 
 
 SANITARY ARRANGEMENT OF DWELLING-HOUSES. 
 
 A Handbook for Householders and Owners of Houses. By A. J. WALLIS- 
 
 TAYLER, A.M.Inst.C.E. Crown 8vo, cloth 2/6 
 
 "This book will be largely read; it will be of considerable service to the public. It is well 
 arranged, easily read, and for the most part devoid of technical terms." Lancet. 
 
 VENTILATION. 
 
 A Text-book to the Practice of the Art of Ventilating Buildings. By W. P. 
 BUCHAN, R.P. Crown 8vo, cloth 3/6 
 
 PLUMBING. 
 
 A Text-book to the Practice of the Art or Craft of the Plumber. By W. P. 
 BUCHAN, R.P. Seventh Edition, Enlarged. Crown 8vo, cloth . . 3/6 
 
 WATER ENGINEERING. 
 
 A Practical Treatise on the Measurement, Storage, Conveyance, and Utilisa 
 tion of Water for the Supply of Towns, for Mill Power, and for other Purposes. 
 By C. SLAGG, A.M. Inst. C.E. Second Edition. Crown 8vo, cloth . 7/6 
 
 SANITARY WORK IN SMALL TOWNS AND VILLAGES. 
 
 By CHARLES SLAGG, A. M. Inst. C.E. Crown 8vo, cloth . . . 3/O 
 
28 CROSBY LOCK WOOD &> SON'S CATALOGUE. 
 
 CARPENTRY, TIMBER, &c. 
 
 THE ELEMENTARY PRINCIPLES OF CARPENTRY. 
 
 A Treatise on the Pressure and Equilibrium of Timber Framing, the Resistance 
 of Timber, and the Construction of Floors, Arches, Bridges, Roofs, Uniting 
 Iron and Stone with Timber, &c. To which is added an Essay on the Nature 
 and Properties of Timber, &c., with Descriptions of the kinds of Wood used 
 in Building ; also numerous Tables of the Scantlings of Timber for different 
 purposes, the Specific Gravities of Materials, &c. By THOMAS TREDGOLD, C.E. 
 With an Appendix of Specimens of Various Roofs of Iron and Stone, Illus- 
 trated. Seventh Edition, thoroughly Revised and considerably Enlarged by 
 E. WYNDHAM TARN, M.A., Author of " The Science of Building," &c. 
 With 61 Plates, Portrait of the Author, and several Woodcuts. In One large 
 
 Vol., 410, cloth 25/O 
 
 "Ought to be in every architect's and every builder's library." Builder. 
 
 " A work whose monumental excellence must commend it wherever skilful carpentry is 
 
 concerned. The author's principles are rather confirmed than impaired by time. The additional 
 
 plates are of great intrinsic value." Building Netus. 
 
 WOODWORKING MACHINERY. 
 
 Its Rise, Progress, and Construction. With Hints on the Management of Saw 
 
 Mills and the Economical Conversion of Timber. Illustrated with Examples 
 
 of Recent Designs by leading English, French, and American Engineers. By 
 
 M. Powis BALE, A.M.Inst.C.E., M.I.M.E. Second Edition, Revised, 
 
 with large Additions, large crown 8vo, 440 pp., cloth . . . . 9/O 
 
 " Mr. Bale is evidently an expert on the subject, and he has collected so much information 
 
 that his book is all-sufficient for builders and others engaged in the conversion of timber.'' Architect. 
 
 'The most comprehensive compendium of wood-working machinery we have seen. The 
 
 author is a thorough master of his subject." Building JVeivs. 
 
 SAW MILLS. 
 
 Their Arrangement and Management, and the Economical Conversion of 
 
 Timber. By M. Powis BALE, A.M.Inst.C.E. Second Edition, Revised. 
 
 Crown 8vo, cloth. [Just Published. 1 Q/6 
 
 " The administration of a large sawing establishment is discussed, and the subject examined 
 
 from a financial standpoint. Hence the size, shape, order, and disposition of saw mills and the like 
 
 are gone into in detail, and the course of the timber is traced from its reception to its delivery in its 
 
 converted state. We could not desire a more complete or practical treatise." Builder. 
 
 THE CARPENTER'S NEW GUIDE. 
 
 Or, Book of Lines for Carpenters ; comprising all the Elementary Principles 
 essential for acquiring a knowledge of Carpentry. Founded on the late PETER 
 NICHOLSON'S standard work. A New Edition, Revised by ARTHUR ASHPITEL, 
 F.S.A. Together with Practical Rules on Drawing, by GEORGE PYNE. 
 With 74 Plates, 410, cloth 1 1 s . 
 
 A PRACTICAL TREATISE ON HANDRAILING. 
 
 Showing New and Simple Methods for Finding the Pitch of the Plank, Drawing 
 the Moulds, Bevelling, Jpinting-up, and Squaring the Wreath. By GEORGE 
 COLLINGS. Second Edition, Revised and Enlarged, to which is added 
 A TREATISE ON STAIR-BUILDING. With Plates and Diagrams . . 2/6 
 
 " Will be found of practical utility in the execution of this difficult branch of joinery." Builder. 
 
 " Almost every difficult phase of this somewhat intricate branch of joinery is elucidated by 
 the aid of plates and explanatory letterpress." Furniture Gazette. 
 
 CIRCULAR WORK IN CARPENTRY AND JOINERY. 
 
 A Practical Treatise on Circular'Work of Single and Double Curvature. By 
 GEORGE COLLINGS. With Diagrams. Second Edition, i2mo, cloth . 2/6 
 
 " An excellent example of what a book of this kind should be. Cheap in price, clear in 
 definition, and practical in the examples selected." Builder. 
 
CARPENTRY, TIMBER, &c. 29 
 
 HANDRAILINQ COMPLETE IN EIGHT LESSONS. 
 
 On the Square-Cut System. By J. S. GOLDTHORP, Head of Building 
 Department, Halifax Technical School. With Eight Plates and over 150 
 Practical Exercises. 4to, cloth 3/6 
 
 " Likely to be of considerable value to joiners and others who take a pride in good work. 
 The arrangement of the book is excellent. We heartily commend it to teachers and students." 
 Timber Trades Journal. 
 
 TIMBER MERCHANT'S and BUILDER'S COMPANION. 
 
 Containing New and Copious Tables of the Reduced Weight and Measure- 
 ment of Deals and Battens, of all sizes, from One to a Thousand Pieces, and 
 the relative Price that each size bears per Lineal Foot to any given Price per 
 Petersburgh Standard Hundred ; the Price per Cube Foot of Square Timber 
 to any given Price per Load of 50 Feet, &c., &c. By WILLIAM DOWSING. 
 Fourth Edition, Revised and Corrected. Crown 8vo, cloth . . . 3/O 
 " We are glad to see a fourth edition of these admirable tables, which for correctness and 
 simplicity of arrangement leave nothing to be desired." Timber Trades Journal. 
 
 THE PRACTICAL TIMBER MERCHANT. 
 
 A Guide for the Use of Building Contractors, Surveyors, Builders, &c., 
 comprising useful Tables for all purposes connected with the Timber Trade, 
 Marks of Wood, Essay on the Strength of Timber, Remarks on the Growth of 
 Timber, &c. By W. RICHARDSON. Second Edition. Fcap. 8vo, cloth . 3/6 
 " This handy manual contains much valuable information for the use of timber merchants, 
 
 builders, foresters, and all others connected with the growth, sale, and manufacture of timber." 
 
 Journal of Forestry. 
 
 PACKING-CASE TABLES. 
 
 Showing the number of Superficial Feet in Boxes or Packing-Cases, from six 
 inches square and upwards. By W. RICHARDSON, Timber Broker. Third 
 Edition. Oblong 4to, cloth 3/6 
 
 " Invaluable labour-saving tables." Ironmonger. 
 
 GUIDE TO SUPERFICIAL MEASUREMENT. 
 
 Tables calculated from i to 200 inches in length by i to 108 inches in breadth. 
 
 For the use of Architects, Surveyors, Engineers, Timber Merchants, 
 
 Builders, &c. By JAMES HAWKINGS. Fourth Edition. Fcap., cloth . 3/6 
 
 " A useful collection of tables to facilitate rapid calculation of surfaces. The exact area of 
 
 any surface of which the limits have been ascertained can be instantly determined. The book will 
 
 be found of the greatest utility to all engaged in building operations." Scotsman. 
 
 PRACTICAL FORESTRY. 
 
 Its Bearing on the Improvement of Estates. By CHARLES E. CURTIS, F.S.I., 
 F.S.S. Second Edition, Revised. Crown 8vo, cloth. [Just Published. 3/6 
 
 THE ELEMENTS OF FORESTRY. 
 
 Designed to afford Information concerning the Planting and Care of Forest 
 Trees for Ornament or Profit, with suggestions upon the Creation and Care of 
 Woodlands. By F. B. HOUGH. Large crown 8vo, cloth . . . "| O/O 
 
 THE TIMBER IMPORTER'S, TIMBER MERCHANT'S, 
 
 AND BUILDER'S STANDARD GUIDE. 
 
 By RICHARD E. GRANDY. Comprising : An Analysis of Deal Standards, 
 Home and Foreign, with Comparative Values and Tabular Arrangements for 
 fixing Net Landed Cost on Baltic and North American Deals, including all 
 intermediate Expenses, Freight, Insurance, &c. ; together with copious Informa- 
 tion for the Retailer and Builder. Third Edition. i2mo, cloth . . 2/O 
 " Everything it pretends to be : built up gradually, it leads one from a forest to a treenail, 
 
 and throws in as a makeweight a host of material concerning bricks, columns, cisterus &c " 
 
 English Mechanic. 
 
3 o CROSBY LOCKWOOD 6- SON'S CATALOGUE. 
 
 DECORATIVE ARTS, &c. 
 
 SCHOOL OF 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, i8j by 12^ in., 
 Illustrated with 24 full-size Coloured Plates ; also 12 plain Plates, comprising 
 154 Figures. Second and Cheaper Edition .... "| 11s. 60. 
 
 LIST OF PLATES : i. VARIOUS TOOLS REQUIRED FOR WOOD PAINTING. 2, 3. WALNUT ; 
 PRELIMINARY STAGES OF GRAINING AND FINISHED SPECIMEN. 4 . TOOLS USED FOR 
 MARBLE PAINTING AND METHOD OF MANIPULATION. 5, 6. ST. REMI MARBLE ; 
 EARLIER OPERATIONS AND FINISHED SPECIMEN. 7. METHODS OF SKETCHING 
 DIFFERENT GRAINS, KNOTS, &c. 8, 9. ASH: PRELIMINARY STAGES AND FINISHED 
 SPECIMEN. 10. METHODS OF SKETCHING MARBLE GRAINS. u, 12. BRECHE MARBLE ; 
 PRELIMINARY STAGES OF WORKING AND FINISHED SPECIMEN. 13. MAPLE ; METHODS 
 OF PRODUCING THE DIFFERENT GRAINS. 14, 15. BIRD'S-EYE MAPLE; PRELIMINARY 
 STAGES AND FINISHED SPECIMEN. 16. METHODS OF SKETCHING THE DIFFERENT 
 SPECIES OF WHITE MARBLE. 17, 18. WHITE MARBLE ; PRELIMINARY STAGES OF 
 PROCESS AND FINISHED SPECIMEN. 19. MAHOGANY; SPECIMENS OF VARIOUS GRAINS 
 AND METHODS OF MANIPULATION. 20, 21. MAHOGANY; EARLIER STAGES AND 
 FINISHED SPECIMEN. 22, 23, 24. SIENNA MARBLE; VARIETIES OF GRAIN, PRELIMINARY 
 STAGES AND FINISHED SPECIMEN. 25, 26, 27. JUNIPER WOOD; METHODS OF PRO- 
 DUCING GRAIN, &c. ; PRELIMINARY STAGES AND FINISHED SPECIMEN. 28, 29, 30. VERT 
 DE MER MARBLE; VARIETIES OF GRAIN AND METHODS OF WORKING, UNFINISHED 
 AND FINISHED SPECIMENS. 31, 32, 33. OAK ; VARIETIES OF GRAIN, TOOLS EMPLOYED 
 AND METHODS OF MANIPULATION, PRELIMINARY STAGES AND FINISHED SPECIMEN. 
 34, 35, 36. WAULSORT MARBLE; VARIETIES OF GRAIN, UNFINISHED AND FINISHED 
 SPECIMENS. 
 
 " Those who desire to attain skill in the art of painting woods and marbles will find advantage 
 in consulting this book. . . . Some of the Working Men's Clubs should give their young men 
 the opportunity to study it." Builder. 
 
 "A comprehensive guide to the art. The explanations of the processes, the manipulation 
 and management of the colours, and the beautifully executed plates will not be the least valuable to 
 the student who aims at making his work a faithful transcript of nature." Building News. 
 
 " Students and novices are fortunate who are able to become the possessors of so noble a 
 work." The Architect. 
 
 ELEMENTARY DECORATION. 
 
 A Guide to the Simpler Forms of Everyday Art. Together with PRACTICAL 
 HOUSE DECORATION. By JAMES W. FACEY. With numerous Illus- 
 trations. In One Vol., strongly half-bound 5/O 
 
 HOUSE PAINTING, GRAINING, MARBLING, AND 
 SIGN WRITING. 
 
 A Practical Manual of. By ELLIS A. DAVIDSON. Seventh Edition. With 
 Coloured Plates and Wood Engravings. i2mo, cloth boards . . . 6/O 
 " A mass of information of use to the amateur and of value to the practical man." English 
 Mechanic. 
 
 THE DECORATOR'S ASSISTANT. 
 
 A Modern Guide for Decorative Artists and Amateurs, Painters, Writers, 
 Gilders, &c. Containing upwards of 600 Receipts, Rules, and Instructions ; 
 with a variety of Information for General Work connected with every Class of 
 Interior and Exterior Decorations, &c. Seventh Edition. 152 pp., cr. 8vo. 1 /O 
 " Full of receipts of value to decorators, painters, gilders, &c. The book contains the gist of 
 
 larger treatises on colour and technical processes. It would be difficult to meet with a work so full 
 
 of varied information on the painter's art." Building News. 
 
 MARBLE DECORATION 
 
 And the Terminology of British and Foreign Marbles. A Handbook for 
 Students. By GEORGE H. BLAGROVE, Author of " Shoring and its Applica- 
 tion," &c. With 28 Illustrations. Crown 8vo, cloth .... 3/6 
 
 "This most useful and much wanted handbook should be in the hands of every architect and 
 builder." Building- World. 
 
 " A carefully and usefully written treatise ; the work is essentially practical." Scotsman. 
 
DECORATIVE ARTS. &c. 31 
 
 DELAMOTTE'S WORKS ON ALPHABETS AND 
 ILLUMINATION. 
 
 ORNAMENTAL ALPHABETS, ANCIENT & MEDI/EVAL. 
 
 From the Eighth Century, with Numerals ; including Gothic, Church-Text, 
 large and small, German, Italian, Arabesque, Initials for Illumination, 
 Monograms, Crosses, &c., &c., for the use of Architectural and Engineering 
 Draughtsmen, Missal Painters, Masons, Decorative Painters, Lithographers, 
 Engravers, Carvers, &c., &c. Collected and Engraved by F. DELAMOTTE, and 
 printed in Colours. New and Cheaper Edition. Royal 8vo, oblong, 
 
 ornamental boards 2/6 
 
 " For those who insert enamelled sentences round gilded chalices, who blazon shop legends 
 
 over shop-doors, who letter church walls with pithy sentences from the Decalogue, this book will be 
 
 useful." Athenczum. 
 
 MODERN ALPHABETS, PLAIN AND ORNAMENTAL. 
 
 Including German, Old English, Saxon, Italic, Perspective, Greek, Hebrew, 
 Court Hand, Engrossing, Tuscan, Riband, Gothic, Rustic, and Arabesque ; 
 with several Original Designs, and an Analysis of the Roman and Old English 
 Alphabets, large and small, and Numerals, for the use of Draughtsmen, 
 Surveyors, Masons, Decorative Painters, Lithographers, Engravers, Carvers, 
 &c. Collected and Engraved by F. DELAMOTTE, and printed in Colours. 
 New and Cheaper Edition. Royal 8vo, oblong, ornamental boards . 2/6 
 " There is comprised in it every possible shape into which the letters of the alphabet and 
 
 numerals can be formed, and the talent which has been expended in the conception of the various 
 
 plain and ornamental letters is wonderful." Standard. 
 
 MEDIAEVAL ALPHABETS AND INITIALS FOR 
 
 ILLUMINATORS. 
 
 By F. G. DELAMOTTE. Containing 21 Plates and Illuminated Title, printed 
 
 in Gold and Colours. With an Introduction by J. WILLIS BROOKS. Fourth 
 
 and Cheaper Edition. Small 410, ornamental boards .... 4/O 
 
 "A volume in which the letters of the alphabet come forth glorified in gilding and all the 
 
 colours of the prism interwoven and intertwined and intermingled." Sun. 
 
 A PRIMER OF THE ART OF ILLUMINATION. 
 
 For the Use of Beginners ; with a Rudimentary Treatise on the Art, Practical 
 Directions for its Exercise, and Examples taken from Illuminated MSS., 
 printed in Gold and Colours. By F. DELAMOTTE. New and Cheaper 
 
 Edition. Small 410, ornamental boards 6/O 
 
 " The examples of ancient MSS. recommended to the student, which, with much good sense, 
 
 the author chooses from collections accessible to all, are selected with judgment and knowledge as 
 
 well as taste." Athenaum. 
 
 THE EMBROIDERER'S BOOK OF DESIGN. 
 
 Containing Initials, Emblems, Cyphers, Monograms, Ornamental Borders, 
 Ecclesiastical Devices, Mediaeval and Modern Alphabets, and National 
 Emblems. Collected by F. DELAMOTTE, and printed in Colours. Oblong 
 
 royal 8vo, ornamental wrapper "1/6 
 
 "The book will be of great assistance to ladies and young children who are endowed with 
 the art of plying the needle in this most ornamental and useful pretty work." East Anglian Times. 
 
 INSTRUCTIONS IN WOOD-CARVING FOR AMATEURS. 
 
 With Hints on Design. By A LADY. With 10 Plates. New and Cheaper 
 
 Edition. Crown 8vo, in emblematic wrapper 2/O 
 
 " The handicraft of the wood-carver, so well as a book can impart it, may be learnt from ' A 
 Lady's ' publication." Athen&um. 
 
 PAINTING POPULARLY EXPLAINED. 
 
 By THOMAS JOHN GULLICK, Painter, and JOHN TIMES, F.S.A. Including 
 Fresco, Oil, Mosaic, Water-Colour, Water-Glass, Tempera, Encaustic, 
 Miniature, Painting on Ivory, Vellum, Pottery, Enamel, Glass, &c. Fifth 
 
 Edition. Crown 8vo, cloth 5/Q 
 
 *** Adopted as a Prize Book at South Kensington. 
 
 " Much may be learned, even by those who fancy they do not require to be taught, from the 
 careful perusal of this unpretending but comprehensive treatise." A rt Journal. 
 
32 CROSBY LOCK WOOD & SON'S CATALOGUE. 
 
 NATURAL SCIENCE, &c. 
 
 THE VISIBLE UNIVERSE. 
 
 Chapters on the Origin and Construction of the Heavens. By J. E. GORE, 
 F.R.A.S., Author of " Star Groups," &c. Illustrated by 6 Stellar Photographs 
 and 12 Plates. Demy 8vo, cloth ~\ 6/O 
 
 " A valuable and lucid summary of recent astronomical theory, rendered more valuable and 
 attractive by a series of stellar photographs and other illustrations." The Times. 
 
 " In presenting a clear and concise account of the present state of our knowledge Mr. Gore 
 has made a valuable addition to the literature of the subject." Nature. 
 
 " Mr. Gore's ' Visible Universe' is one of the finest works on astronomical science that have 
 recently appeared in our language. In spirit and in method it is scientific from cover to cover, but 
 the style is so clear and attractive that it will be as acceptable and as readable to those who make 
 no scientific pretensions as to those who devote themselves specially to matters astronomical." 
 Leeds Mercury. 
 
 STAR GROUPS. 
 
 A Student's Guide to the Constellations. By J. ELLARD GORE, F.R.A.S., 
 M.R.I. A., &c., Author of "The Visible Universe," "The Scenery of the 
 
 Heavens," &c. With 30 Maps. Small 410, cloth 5/O 
 
 " The volume contains thirty maps showing stars of the sixth magnitude the usual naked-eye 
 limit and each is accompanied by a brief commentary adapted to facilitate recognition and bring- 
 to notice objects of special interest. For the purpose of a preliminary survey of the ' midnight 
 pomp ' of the heavens nothing could be better than a set of delineations averaging scarcely twenty 
 square inches in area and including nothing that cannot at once be identified." Saturday Re-view. 
 
 AN ASTRONOMICAL GLOSSARY. 
 
 Or, Dictionary of Terms used in Astronomy. With Tables of Data and Lists 
 of Remarkable and Interesting Celestial Objects. By J. ELLARD GORE, 
 F.R.A.S., Author of " The Visible Universe," &c. Small crown 8vo, cloth. 
 
 2/6 
 
 " A very useful little work for beginners in astronomy, and not to be despised by more 
 advanced students." The Times. 
 
 " A very handy book . . . the utility of which is much increased by its valuable tables of 
 astronomical data. " Athentzum. 
 
 THE MICROSCOPE. 
 
 Its Construction and Management. Including Technique, Photo-micrography, 
 and the Past and Future of the Microscope. By Dr. HENRI VAN HEURCK. 
 Re-Edited and Augmented from the Fourth French Edition, and Translated 
 by WYNNE E. BAXTER, F.G.S. 400 pp., with upwards of 250 Woodcuts, 
 imp. 8vo, cloth 1 8/O 
 
 " A translation of a well-known work, at once popular and comprehensive." Times. 
 
 "The translation is as felicitous as it is accurate." Nature. 
 
 ASTRONOMY. 
 
 By the late Rev. ROBERT MAIN, M.A., F.R.S. Third Edition, Revised by 
 WILLIAM THYNNE LYNN, B.A., F.R.A.S., formerly of the Royal Observatory, 
 Greenwich. i2mo, cloth 2/O 
 
 "A sound and simple treatise, very carefully edited, and a capital book for beginners." 
 Knowledge. 
 
 "Accurately brought down to the requirements of the present time by Mr. Lynn." 
 Educational Times. 
 
 A MANUAL OF THE MOLLUSCA. 
 
 A Treatise on Recent and Fossil Shells. By S. P. WOODWARD, A.L.S., 
 F.G.S. With an Appendix on RECENT AND FOSSIL CONCHOLOGICAL 
 DISCOVERIES, by RALPH TATE, A.L.S., F.G.S. With 23 Plates and 
 upwards of 300 Woodcuts. Reprint of Fourth Edition (1880). Crown Svo, 
 
 cloth 7/6 
 
 "A most valuable storehouse of conchological and geological information." Science Gossip. 
 
 THE TWIN RECORDS OF CREATION. 
 
 Or, Geology and Genesis, their Perfect Harmony and Wonderful Concord 
 
 By G. W. V. LE VAUX. Svo, cloth 5/O 
 
 " A valuable contribution to the evidences of Revelation, and disposes very conclusively is 
 
 the arguments of those who would set God's Works against God's Word. No real difficulty is 
 
 shirked, and no sophistry is left unexposed. " The Rock. 
 
NATURAL SCIENCE, &>c. 33 
 
 HANDBOOK OF MECHANICS. 
 
 By Dr. LARDNER. Enlarged and re-written by BENJAMIN LOEWY, F.R.A.S. 
 378 Illustrations. Post 8vo, cloth , ....... 6/O 
 
 " The perspicuity of the original has been retained, and chaptersTwhich had become obsolete 
 have been replaced by others of more modern character. The explanations throughout are 
 studiously popular, and care has been taken to show the application of the various branches of 
 physics to the industrial arts, and to the practical business of life." Mining Journal. 
 
 HANDBOOK OF HYDROSTATICS AND PNEUMATICS. 
 
 By Dr. LARDNER. New Edition, Revised and Enlarged by BENJAMIN LOEWY, 
 F.R.A.S. With 236 Illustrations. Post 8vo, cloth .... 5/Q 
 "For those 'who desire to attain an accurate knowledge of physical science without the 
 profound methods of mathematical investigation,' this work is well adapted." Chemical Nelvs. 
 
 HANDBOOK OF HEAT. 
 
 By Dr. LARDNER. Edited and re-written by BENJAMIN LOEWY, F.R.A.S., &c. 
 117 Illustrations. Post 8vo, cloth 6/O 
 
 "The style is always clear and precise, and conveys instruction without leaving any cloudiness 
 or lurking doubts behind." Engineering. 
 
 HANDBOOK OF OPTICS. 
 
 By Dr. LARDNER. New Edition. Edited by T. OLVER HARDING, B. A. Lond. 
 
 With 298 Illustrations. Small 8vo, 448 pp., cloth 5/O 
 
 " Written by one of the ablest English scientific writers, beautifully and elaborately illustrated." 
 Mechanics' Magazine. 
 
 ELECTRICITY, MAGNETISM, AND ACOUSTICS. 
 
 By Dr. LARDNER. Edited by GEO. CAREY FOSTER, B.A., F.C.S. With 
 400 Illustrations. Small 8vo, cloth 5/O 
 
 " The book could not have been entrusted to any one better calculated to preserve the terse 
 and lucid style of Lardner, while correcting his errors and bringing up his work to the present 
 state of scientific knowledge." ^Popular Science Review. 
 
 HANDBOOK OF ASTRONOMY. 
 
 By Dr. LARDNER. Fourth Edition. Revised and Edited by EDWIN DUNKIN, 
 F.R.A.S., Royal Observatory, Greenwich. With 38 Plates and upwards of 
 100 Woodcuts. 8vo, cloth 9/6 
 
 "Probably no other book contains the same amount of information in so compendious and 
 well arranged a form certainly none at the price at which this is offered to the public." Athenceum. 
 
 " We can do no other than pronounce this work a most valuable manual of astronomy, and 
 we strongly recommend it to all who wish to acquire a general but at the same time correct 
 acquaintance with this sublime science.'' Quarterly Journal of Science 
 
 MUSEUM OF SCIENCE AND ART. 
 
 Edited by Dr. LARDNER. With upwards of 1,200 Engravings on Wood. In 
 Six Double Volumes, 1 1 s. in a new and elegant cloth binding ; or hand- 
 somely bound in half-morocco 1 11s. 60. 
 
 " A cheap and interesting publication, alike informing and attractive. The papers combine 
 subjects of importance and great scientific knowledge, considerable inductive powers, and a popular 
 style of treatment." Spectator. 
 
 Separate books formed from the above. 
 
 Common Things Explained. 55. 
 The Microscope. 25. cloth. 
 Popular Geology, zs. 6d. cloth. 
 Popular Physics. 25. 6d. cloth. 
 
 Steam and its Uses. ->.s. cloth. 
 Popular Astronomy. 45. 6d. cloth. 
 The Bee and White Ants. 25. cloth. 
 The Electric Telegraph, is. 6d. 
 
 NATURAL PHILOSOPHY FOR SCHOOLS. 
 
 By Dr. LARDNER. Fcap. 8vo 3/6 
 
 "A very convenient class book for junior students in private schools." British Quarterly 
 Re-vie-w. 
 
 ANIMAL PHYSIOLOGY FOR SCHOOLS. 
 
 By Dr. LARDNER. Fcap. 8vo 3/6 
 
 " Clearly written, well arranged, and excellently illustrated." Gardener's Chronicle. 
 
 THE ELECTRIC TELEGRAPH. 
 
 By Dr. LARDNER. Revised by E. B. BRIGHT, F.R.A.S. Fcap. 8vo. . 2/6 
 One of the most readable books extant on the Electric Telegraph. 'English Mechanic. 
 
 I. C 
 
34 CROSBY LOCK WOOD &- SON'S CATALOGUE. 
 
 CHEMICAL MANUFACTURES, 
 CHEMISTRY, &c. 
 
 THE GAS 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., 450 pp., crown 8vo, fully Illustrated, leather. 
 
 [ Just Published. 1 Q/ 6 
 
 "The book contains a vast amount of information. The author goes consecutively through 
 the engineering details and practical methods involved in each of the different processes or parts 
 of a gas-works. He has certainly succeeded in making a compilation of hard matters of fact 
 absolutely interesting to read." Gas World. 
 
 " A useful work of reference for the gas engineer and all interested in lighting or heating by 
 gas, while the analyses of the various descriptions of gas will be of value to the technical chemist. 
 All matter in any way connected with the manufacture and use of gas is dealt with. The book has 
 evidently been carefully compiled, and certainly constitutes a useful addition to gas literature. " 
 Builder. 
 
 "The volume contains a great quantity of specialised information, compiled, we believe, from 
 trustworthy sources, which should make it of considerable value to those for whom it is specifically 
 produced." Engineer. 
 
 LIGHTING BY ACETYLENE 
 
 Generators, Burners, and Electric Furnaces. By WILLIAM E. GIBBS, M.E. 
 With 66 Illustrations. Crown 8vo, cloth. [Just Published. 7/6 
 
 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 
 
 Analyses, Examples and Suggestions. By H. J. PHILLIPS, F.I.C., F.C.S. 
 
 Second Edition, Enlarged. Crown 8vo, 400 pp., with Illustrations, cloth 1 0/6 
 
 " In this work the author has rendered no small service to a numerous body of practical 
 
 men. . . . The analytical methods may be pronounced most satisfactory, being as accurate as the 
 
 despatch required of engineering chemists permits." Cheinicai A'evvs. 
 
 " Full of good things. As a handbook of technical analysis, it is very welcome." Builder. 
 "The analytical methods given are, as a whole, such as are likely to give rapid and trust- 
 worthy results in experienced hands. . . . There is much excellent descriptive matter in the work, 
 the chapter on ' Oils and Lubrication ' being specially noticeable in this respect." Engineer. 
 
 NITRO=EXPLOSIVE5. 
 
 A Practical Treatise concerning the Properties, Manufacture, and Analysis 
 of Nitrated Substances, including the Fulminates, Smokeless Powders, and 
 Celluloid. By P. G. SANFORD, F.I. C., Consulting Chemist to the Cotton Powder 
 Company, &c. With Illustrations. Crown 8vo, cloth. [Just Published. QIQ 
 " Any one having the requisite apparatus and materials could make nitrp-glycerine or gun- 
 cotton, to say nothing of other explosives, by the aid of the instructions in this volume. This is 
 one of the very few text-books in which can be found just what is wanted. Mr. Sanford goes 
 through the whole list of explosives commonly used, names any given explosive, and tells us of what 
 it is composed and how it is manufactured. The book is excellent throughout." Engineer. 
 
 A HANDBOOK ON MODERN EXPLOSIVES. 
 
 A Practical 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, 
 
 Mining Engineer and Metallurgical Chemist. Second Edition, Enlarged. 
 
 With 150 Illustrations. Crown 8vo, cloth. [ Just Published. ~\ 2/6 
 
 " Useful not only to the miner, but also to officers of both services to whom blasting and the 
 
 use of explosives generally may at any time become a necessary auxiliary." Nature. 
 
 DANGEROUS GOODS. 
 
 Their Sources and Properties, Modes of Storage and Transport. With Notes 
 and Comments on Accidents arising therefrom, together with the Government 
 and Railway Classifications, Acts of Parliament, &c. A Guide for the Use of 
 Government and Railway Officials, Steamship Owners, Insurance Companies 
 and Manufacturers, and Users of Explosives and Dangerous Goods. By 
 H. JOSHUA PHILLIPS, F.I.C., F.C.S. Crown 8vo, 374 pp., cloth . . 9/O 
 Merits a wide circulation, and an intelligent, appreciative study." Chemical Netur. 
 
CHEMICAL MANUFACTURES, CHEMISTRY, &c. 35 
 A MANUAL OF THE ALKALI TRADE. 
 
 Including the Manufacture of Sulphuric Acid, Sulphate of Soda, and Bleaching 
 Powder. By JOHN LOMAS, Alkali Manufacturer, Newcastle-upon-Tyne and 
 London. 390 pp. of Text. With 232 Illustrations and Working Drawings, 
 Second Edition, with Additions. Super-royal 8vo, cloth . . "1 "1 Os. 
 " This book is written by a manufacturer for manufacturers. The working details of the most 
 approved forms of apparatus are given, and these are accompanied by no less than 232 wood 
 engravings, all of which may be used for the purposes of construction. Every step in the manu- 
 facture is very fully described in this manual, and each improvement explained." Athentzum, 
 
 " We find not merely a sound and luminous explanation of the chemical principles of the 
 trade, but a notice of numerous matters which have a most important bearing on the successful 
 conduct of alkali works, but which are generally overlooked by even experienced technological 
 authors." Chemical Review. 
 
 THE BLOWPIPE IN CHEMISTRY, MINERALOGY, AND 
 GEOLOGY. 
 
 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. With 120 Illustrations. Second Edition, Enlarged. 
 Crown 8vo, cloth 5/O 
 
 " The student who goes conscientiously through the course of experimentation here laid down 
 will gain a better insight into inorganic chemistry and mineralogy than if he had ' got up ' any of the 
 best text-books of the day, and passed any number of examinations in their contents." Chemical 
 
 THE MANUAL OF COLOURS AND DYE-WARES. 
 
 Their Properties, Applications, Valuations, Impurities and Sophistications. 
 
 For the Use of Dyers, Printers, Drysalters, Brokers, &c. By J. W. SLATER. 
 
 Second Edition, Revised and greatly Enlarged. Crown 8vo, cloth . 716 
 
 " A complete encyclopaedia of the materia tinctoria. The information given respecting each 
 
 article is full and precise, and the methods of determining the value of articles such as these, so 
 
 liable to sophistication, are given with clearness, and are practical as well as valuable." Chemist 
 
 and Druggist. 
 
 " There is no other work which covers precisely the same ground. To students preparing 
 for examinations in dyeing and printing it will prove exceedingly useful." Chemical News, 
 
 A HANDY BOOK FOR BREWERS. 
 
 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 HERBERT EDWARDS WRIGHT, M.A. Second Edition, Enlarged. Crown 
 
 8vo, 530 pp., cloth. [Just Published. 1 2/6 
 
 " May be consulted with advantage by the student who is preparing himself for examinational 
 
 tests, while the scientific brewer will find in it a resume' of all the most important discoveries of 
 
 modern times. The work is written throughout in a clear and concise manner, and the author 
 
 takes great care to discriminate between vague theories and well-established facts." Brewers' 
 
 Journal. 
 
 " We have great pleasure in recommending this handy book, and have no hesitation in saying 
 that it is one of the best if not the best which has yet been written on the subject of beer-brewing 
 in this country; it should have a place on the shelves of every brewer's library." Brewers' 
 Guardian. 
 
 " Although the requirements of the student are primarily considered, an acquaintance of half- 
 an-hour's duration cannot fail, to impress the practical brewer with the sense of having found a 
 trustworthy guide and practical counsellor in brewery matters." Chemical Trade Journal. 
 
 FUELS: SOLID, LIQUID, AND GASEOUS. 
 
 Their Analysis and Valuation. For the Use of Chemists and Engineers. By 
 
 H. J. PHILLIPS, F.C.S., formerly Analytical and Consulting Chemist to to*; 
 
 G.E. Rlwy. Third Edition, Revised and Enlarged. Crown 8vo, cloth 2/O 
 
 " Ought to have its place in the laboratory of every metallurgical establishment and wherever 
 
 fuel is used on a large scale." Chemical News 
 
36 CROSBY LOCKWOOD & SON'S CATALOGUE. 
 
 THE ARTISTS' MANUAL OF PIGMENTS. 
 
 Showing their Composition, Conditions of Permanency, Non-Permanency, and 
 
 Adulterations ; Effects in Combination with Each Other and with Vehicles ; 
 
 and the most Reliable Tests of Purity. By H. C. STANDAGE. crown 8vo. 2/6 
 
 " This work is indeed mui 'turn-in -parvo, and we can, with good conscience, recommend it to 
 
 all who come in contact with pigments, whether as makers, dealers, or users." Chemical Review. 
 
 A POCKET=BOOK OF MENSURATION AND GAUGING. 
 
 Containing Tables, Rules, and Memoranda for Revenue Officers, Brewers, 
 Spirit Merchants, &c. By J. B. MANT, Inland Revenue. Second Edition, 
 Revised. i8mo, leather 4/O 
 
 "This handy and useful book is adapted to the requirements of the Inland Revenue Depart- 
 ment, and will be a favourite book of reference." Civilian. 
 
 " Should be in the hands of every practical brewer." Breviers' Journal. 
 
 INDUSTRIAL ARTS, TRADES, AND 
 MANUFACTURES. 
 
 MODERN CYCLES. 
 
 A Practical Handbook on their Construction and Repair. By A. J. WALLIS- 
 
 TAYLER, A. M. Inst. C. E. Author of " Refrigerating Machinery," &c. With 
 
 upwards of 300 Illustrations. Crown 8vo, cloth. [Just Published. 1 Q/6 
 
 " The large trade that is done in the component parts of bicycles has placed in the way of 
 
 men mechanically inclined extraordinary facilities for building bicycles for their own use. . The 
 
 book will prove a valuable guide for all those who aspire to the manufacture or repair of their own 
 
 machines." The Field. 
 
 " A most comprehensive and up-to-date treatise." The Cycle. 
 
 "A very useful book, which is quite entitled to rank as a standard work for students of cycle 
 construction. " ' 
 
 TEA MACHINERY AND TEA FACTORIES. 
 
 A Descriptive Treatise on the Mechanical Appliances required on Tea 
 Plantations in the Preparation f Tea for the Market. By A. J. W. TAVLER, 
 A.M. Inst. C.E. With about 200 Illustrations. Medium 8vo. 
 
 [Nearly Ready. Price, about 25/O 
 
 TEA PLANTING AND MANUFACTURE 
 
 (A Text Book of). Comprising Chapters on the History and Development of 
 the Industry, the Cultivation of the Plant, the Preparation of the Leaf for the 
 Market, &c. By DAVID CROLE, late of the Jokai Tea Company, &c. With 
 Plates and other Illustrations. Medium 8vo, cloth .... 1 6/O 
 
 COTTON MANUFACTURE. 
 
 A Manual of Practical Instruction of the Processes of Opening, Carding, 
 Combing, Drawing, Doubling and Spinning of Cotton, the Methods of 
 Dyeing, &c. For the Use of Operatives, Overlookers, and Manufacturers. 
 By JOHN LISTER, Technical Instructor, Pendleton. 8vo, cloth . . 7/6 
 
 " A distinct advance in the literature of cotton manufacture." Machinery. 
 
 " It is thoroughly reliable, fulfilling nearly all the requirements desired." Glasgow Herald. 
 
 FLOUR MANUFACTURE. 
 
 A Treatise on Milling Science and Practice. By FRIEDRICH KICK, Imperial 
 
 Regierungsrath, Professor of Mechanical Technology in the Imperial German 
 
 Polytechnic Institute, Prague. Translated from the Second Enlarged and 
 
 Revised Edition with Supplement. By H. H. P. POWLES, Assoc. Memb. 
 
 Institution of Civil Engineers. Nearly 400 pp. Illustrated with 28 Folding 
 
 Plates, and 167 Woodcuts. Royal 8vo, cloth ..... 1 5 S . 
 
 " This valuable work is, and will remain, the standard authority on the science of milling. . . . 
 
 The miller who has read and digested this work will have laid the foundation, so to speak, of a 
 
 successful career ; he will have acquired a number of general principles which he can proceed to 
 
 apply. In this handsome volume we at last have the accepted text-book of modern milling in good, 
 
 so-ind English, which has little, if any, trace of the German idiom." The Miller. 
 
INDUSTRIAL AND USEFUL ARTS. 37 
 
 CEMENT5, PASTES, GLUES, AND GUMS. 
 
 A Practical Guide to the Manufacture and Application of the various Aggluti- 
 nants required in the Building, Metal-Working, Wood-Working, and Leather- 
 Working Trades, and for Workshop, Laboratory or Office Use. With upwards 
 of 900 Recipes and Formulae. By H. C. STANDAGE, Chemist. Third Edition. 
 Crown Svo, cloth. [Just Published. 2/O 
 
 " We have pleasure in speaking favourably of this volume. So far as we have had 
 experience, which is not inconsiderable, this manual is trustworthy." Athenaum. 
 
 " As a revelation of what are considered trade secrets, this book will arouse an amount of 
 curiosity among the large number of industries it touches." Daily Chronicle. 
 
 THE ART OF SOAP-MAKING. 
 
 A Practical Handbook of the Manufacture of Hard and Soft Soaps, Toilet 
 
 Soaps, &c. Including many New Processes, and a Chapter on the Recovery of 
 
 Glycerine from Waste Leys. By ALX. WATT. Fifth Edition, Revised, with 
 
 an Appendix on Modern Candlemaking. Crown Svo, cloth . . . 716 
 
 "The work will prove very useful, not merely to the technological student, but. to the 
 
 practical soap boiler who wishes to understand the theory of his art." Chemical News. 
 
 " A thoroughly practical treatise on an art which has almost no literature in our language. 
 We congratulate the author on the success of his endeavour to fill a void in English technical 
 literature." Nature. 
 
 PRACTICAL PAPER-MAKING. 
 
 A Manual for Paper-Makers and Owners and Managers of Paper-Mills. With 
 Tables, Calculations, &c. By G. CLAPPERTON, Paper-Maker. With Illus- 
 trations of Fibres from Micro-Photographs. Crown Svo, cloth . . 5/O 
 " The author caters for the requirements of responsible mill hands, apprentices, &c., whilst 
 his manual will be found of great service to students of technology, as well as to veteran paper- 
 makers and mill owners. The illustrations form an excellent feature." The World's Paper Trade 
 Review. 
 
 " We recommend everybody interested in the trade to get a copy of this thoroughly practical 
 book." Paper Making. 
 
 THE ART OF 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 ALEXANDER WATT, Author of "The Art of Soap-Making." With Illus- 
 trations. Crown Svo, cloth 716 
 
 "It may be regarded as the standard work on the subject. The book is full of valuable 
 information. The 'Art of Paper-Making' is in every respect a model of a text-book, either for a 
 technical class, or for the private student." Paper and Printing Trades Journal. 
 
 A TREATISE ON PAPER 
 
 For Printers and Stationers. With an Outline of Paper Manufacture ; Complete 
 Tables of Sizes, and Specimens of Different Kinds of Paper. By RICHARD 
 PARKINSON, late of the Manchester Technical School. Demy Svo, cloth. 
 
 {Just Published. 3/6 
 
 THE ART OF LEATHER MANUFACTURE. 
 
 Being a Practical Handbook, in which the Operations of Tanning, Currying, 
 and Leather Dressing are fully Described, and the Principles of Tanning 
 Explained, and many Recent Processes Introduced ; as also Methods for the 
 Estimation of Tannin, and a Description of the Arts of Glue Boiling, Gut 
 Dressing, &c. By ALEXANDER WATT, Author of " Soap-Making," &c. 
 
 Fourth Edition. Crown Svo, cloth 9/O 
 
 " A sound, comprehensive treatise on tanning and its accessories. The book is an eminently 
 
 valuable production, which redounds to the credit of both author and publisher?." Chemical 
 
 Review. 
 
 THE ART OF BOOT AND SHOE MAKING. 
 
 A Practical Handbook, including Measurement, Last-Fitting, Cutting-Out, 
 Closing and Making, with a Description of the most approved Machinery 
 Employed. By JOHN B. LENO, late Editor of St. Crispin, and The Boot and 
 Shoe-Maker. 12010, cloth. ......... 2/O 
 
38 CROSBY LOCK WOOD fr SON'S CATALOGUE. 
 WOOD ENGRAVING. 
 
 A Practical and Easy Introduction to the Study of the Art. By W. N. BROWN. 
 12010, cloth ............ "1/6 
 
 " The book is clear and complete, and will be useful to any one wanting to understand the 
 first elements of the beautiful art of wood engraving. "Graphic. 
 
 MODERN HOROLOGY, IN THEORY AND PRACTICE. 
 
 Translated from the French of CLAUDIUS SAUNIER, ex-Director of the School 
 of Horology at Macon, by JULIEN TRIPPLIN, F.R.A.S., Besancon Watch 
 Manufacturer, and EDWARD RIGG, M.A., Assayer in the Royal Mint. With 
 Seventy-eight Woodcuts and Twenty-two Coloured Copper Plates. Second 
 Edition. Super-royal 8vo, cloth, 2 2s. ', half-calf . . . 21Os. 
 " There is no horological work in the English language at all to be compared to this produc- 
 tion of M. Saunier's for clearness and completeness. It is alike good as a guide for the student and 
 as a reference for the experienced horologist and skilled workman." Horoiogical Journal. 
 
 " The latest, the most complete, and the most reliable of those literary productions to which 
 continental watchmakers are indebted for the mechanical superiority over their English brethren 
 in fact, the Book of Books, is M. Saunier's ' Treatise.'" Watchmaker, yeiveller, and Silversmith. 
 
 THE WATCH ADJUSTER'S MANUAL. 
 
 A Practical Guide for the Watch and Chronometer Adjuster in Making, 
 Springing, Timing and Adjusting for Isochronism, Positions and Temperatures. 
 By C. E. FRITTS. 370 pp., with Illustrations, 8 vo, cloth . . . 1 6/O 
 
 THE 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. Third Edition. 8vo, cloth. 9/Q 
 
 " 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, 
 
 " It is impossible to speak too highly of its excellence. It fulfils every requirement in a 
 handbook intended for the use of a workman. Should be found in every workshop." Watch and 
 Clockmaker. 
 
 A HISTORY OF WATCHES & OTHER TIMEKEEPERS. 
 
 By JAMES F. KENDAL, M.B.H. Inst. Boards, 1/6; or cloth, gilt . 2/6 
 'The best which has yet appeared on this subject in the English language." Industries. 
 the book where you may, there is interesting mattei 
 ! ancient or modem horologer." Saturday Review. 
 
 ELECTRO=DEPOSITION. 
 
 A Practical Treatise on the Electrolysis of Gold, Silver, Copper, Nickel, and 
 other Metals and Alloys. With Descriptions of Voltaic Batteries, Magneto 
 and Dynamo-Electric Machines, Thermopiles, and of the Materials and 
 Processes used in every Department of the Art, and several Chapters on 
 ELECTRO-METALLURGY. By ALEXANDER WATT, Author of "Electro- 
 Metallurgy," &c. Third Edition, Revised. Crown 8vo, cloth . . 9/Q 
 "Eminently a book for the practical worker in electro-deposition. It contains practical 
 
 descriptions of methods, processes and materials, as actually pursued and used in the workshop." 
 
 Engineer. 
 
 ELECTRO-METALLURGY. 
 
 Practically Treated. By ALEXANDER WATT. Tenth Edition, including the 
 
 most recent Processes. i2mo, cloth 3/6 
 
 " From this book both amateur and artisan may learn everything necessary for the successful 
 prosecution of electroplating." Iron. 
 
 JEWELLER'S ASSISTANT IN WORKING IN GOLD. 
 
 A Practical Treatise for Masters and Workmen, Compiled from the Experience 
 of Thirty Years' Workshop Practice. By GEORGE E. GEE, Author of "The 
 
 Goldsmith's Handbook," &c. Crown 8vo, cloth 7/6 
 
 " This manual of technical education is apparently destined to be a valuable auxiliary to a 
 handicraft which is certainly capable of great improvement." The Times. 
 
INDUSTRIAL AND USEFUL ARTS. 39 
 
 ELECTROPLATING. 
 
 A Practical Handbook on the Deposition of Copper, Silver, Nickel, Gold, 
 Aluminium, Brass, Platinum, &c., &c. By J. W. URQUHART, C.E. Fourth 
 Edition, Revised. Crown 8vo, cloth [Just Published. 5/Q 
 
 " An excellent practical manual." Engineering. 
 
 *' An excellent work, giving the newest information." Horological Journal* 
 
 ELECTROTYPING. 
 
 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 5/O 
 
 " The book is thoroughly practical ; the reader is, therefore, conducted through the leading 
 laws of electricity, then through the metals used by electrotypers, the apparatus, and the depositing 
 processes, up to the final preparation of the work." Art Journal. 
 
 GOLDSMITH'S HANDBOOK. 
 
 By GEORGE E. GEE, Jeweller, &c. Fifth Edition. i2mo, cloth . . 3/Q 
 "A good, sound educator, and will be generally accepted as an authority." Horological 
 Journal. 
 
 SILVERSMITH'S HANDBOOK. 
 
 By GEORGE E. GEE, Jeweller, &c. Third Edition, with numerous Illustra- 
 tions. i2mo, cloth 3/O 
 
 "The chief merit of the work is its practical character. . . . The workers in the trade will 
 speedily discover its merits when they sit down to study it." English Mechanic. 
 
 *** The. above two works together, strongly half-bound, price 7s. 
 
 SHEET METAL WORKER'S INSTRUCTOR. 
 
 Comprising a Selection of Geometrical Problems and Practical Rules for 
 Describing the Various Patterns Required by Zinc, Sheet-Iron, Copper, and 
 Tin-Plate Workers. By REUBEN HENRY WARN. New Edition, Revised and 
 greatly Enlarged by JOSEPH G. HORNER, A.M.I.M.E. Crown 8vo, 254 pp., 
 with 430 Illustrations, cloth. [Just Published. 7IQ 
 
 BREAD & BISCUIT BAKER'S & SUGAR-BOILER'S 
 
 ASSISTANT. 
 
 Including a large variety of Modern Recipes. With Remarks on the Art of 
 
 Bread-making. By ROBERT WELLS. Third Edition. Crown 8vo, cloth . 2/O 
 
 " A large number of wrinkles for the ordinary cook, as well as the baker." Saturday Review. 
 
 PASTRYCOOK & 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." Crown 8vo, 
 cloth 2/O 
 
 " We cannot speak too highly of this really excellent work. In these days of keen competition 
 our readers cannot do better than purchase this book." Bakers' Times. 
 
 ORNAMENTAL CONFECTIONERY. 
 
 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. Second Edition. Crown 8vo . 5/O 
 
 " A valuable work, practical, and should be in the hands of every baker and confectioner. 
 
 The illustrative designs are alone worth treble the amount charged for the whole work." Bakers' 
 
 Times. 
 
 THE MODERN FLOUR CONFECTIONER, WHOLESALE 
 
 AND RETAIL. 
 
 Containing a large Collection of Recipes or Cheap Cakes, Biscuits, &c. With 
 
 remarks on the Ingredients Used in their Manufacture. By ROBERT WELLS, 
 
 Author of " The Bread and Biscuit Baker," &c. Crown 8vo, cloth . 2/O 
 
 " The work is of a decidedly practical character, and in every recipe regard is had to economical 
 
 working." North British Daily Mail. 
 
 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 Illustrations. Square 8vo, cloth . . . 5/Q 
 
4 o CROSBY LOCKWOOD & SON'S CATALOGUE. 
 
 HANDYBOOK8 FOR HANDICRAFTS. 
 
 BY PAUL N. HASLUCK. 
 Editor of " Work " (New Series), Author of " Lathe Work," " Milling Machines," &c. 
 
 Crown 8vo, 144 pp., price is. each. 
 
 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 of modern tools, appliances, and 
 processes. 
 
 THE METAL TURNER'S HANDYBOOK. 
 
 A Practical Manual for Workers at the Foot-Lathe. With over 100 Illus- 
 trations. "I/O 
 
 " The book will be of service alike to the amateur and the artisan turner. It displays 
 thorough knowledge of the subject." Scotsman. 
 
 THE WOOD TURNER'S HANDYBOOK. 
 
 A Practical Manual for Workers at the Lathe. With over 100 Illustrations. 
 
 1/O 
 
 " We recommend the book to young turners and amateurs. A multitude of workmen have 
 hitherto sought in vain for a manual of this special industry." Mechanical World. 
 
 THE WATCH JOBBER'S HANDYBOOK. 
 
 A Practical Manual on Cleaning, Repairing, and Adjusting. With upwards of 
 TOO Illustrations "I/O 
 
 " We strongly advise all young persons connected with the watch trade to acquire and study 
 this inexpensive -wor^'Clerken-well Chronicle. 
 
 THE PATTERN MAKER'S HANDYBOOK. 
 
 A Practical Manual on the Construction of Patterns for Founders. With 
 
 upwards of 100 Illustrations "I/O 
 
 " A most valuable, if not indispensable manual for the pattern maker." Knowledge. 
 
 THE 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 "I/O 
 
 " A very clever and useful book, which should be found in every workshop ; and it should 
 certainly find a place in all technical schools." Saturday Review, 
 
 THE MODEL ENGINEER'S HANDYBOOK. 
 
 A Practical Manual on the Construction of Model Steam Engines. With 
 
 upwards of 100 Illustrations. 1 /O 
 
 " Mr. Hasluck has produced a very good little book." Builder. 
 
 THE CLOCK JOBBER'S HANDYBOOK. 
 
 A Practical Manual on Cleaning, Repairing, and Adjusting. With upwards of 
 100 Illustrations ............ "I/O 
 
 " It is of inestimable service to those commencing the trade." Coventry Standard. 
 
 THE CABINET MAKER'S HANDYBOOK. 
 
 A Practical Manual on the Tools, Materials, Appliances, and Processes 
 employed in Cabinet Work. With upwards of 100 Illustrations . . 1 /O 
 " Mr. Hasluck's thorough-going little Handybook is amongst the most practical guides we 
 have seen for beginners in cabinet-work." Saturday Re-view. 
 
 THE WOODWORKER'S HANDYBOOK OF MANUAL 
 
 INSTRUCTION. 
 
 Embracing Information on the Tools, Materials, Appliances and Processes 
 
 Employed in Woodworking. With 104 Illustrations 1 JQ 
 
 OPINIONS OF THE PRESS. 
 
 " Written by a man who knows, not only how work ought to be done, but how to do it, and 
 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 experience." Daily Chronicle 
 "Practical, sensible, and remarkably cheap." Journal of Education. 
 "Concise, clear, and practical." Saturday Review. 
 
COMMERCE, COUNTING-HOUSE WORK, TABLES, &c. 41 
 
 COMMERCE, COUNTING-HOUSE WORK, 
 TABLES, &c. 
 
 LESSONS IN COMMERCE. 
 
 By Professor R. GAMBARO, of the Royal High Commercial School at Genoa. 
 
 Edited and Revised by JAMES GAULT, Professor of Commerce and Commercial 
 
 Law in King's College, London. Second Edition, Revised. Crown 8vo . 3/6 
 
 " The publishers of this work have rendered considerable service to the cause of commercial 
 
 education by the opportune production of this volume. . . . The work is peculiarly acceptable to 
 
 English readers and an admirable addition to existing class books. In a phrase, we think the work 
 
 attains its object in furnishing a brief account of those laws and customs of British trade with which 
 
 the commercial man interested therein should be familiar." Chamber of Commerce journal. 
 
 " An invaluable guide in the hands of those who are preparing for a commercial career, and, 
 in fact, the information it contains on matters of business should be impressed on every one." 
 Counting House. 
 
 THE FOREIGN COMMERCIAL CORRESPONDENT. 
 
 Being Aids to Commercial Correspondence in Five Languages English, 
 French, German, Italian, and Spanish. By CONRAD E. BAKER. Second 
 Edition. Crown 8vo, cloth 3/6 
 
 " Whoever wishes to correspond in all the languages mentioned by Mr. Baker cannot do 
 better than study this work, the materials of which are excellent and conveniently arranged. They 
 consist not of entire specimen letters, but what are far more useful short passages, sentences, or 
 phrases expressing the same general idea in various forms." Athenaum. 
 
 " A careful examination has convinced us that it is unusually complete, well arranged and 
 reliable. The book is a thoroughly good one." Schoolmaster. 
 
 FACTORY ACCOUNTS: their PRINCIPLES &. 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; the Factory and Workshop Acts, &c. , 
 including also a Glossary of Terms and a large number of Specimen Rulings. 
 By EMILE GARCKE and J. M. FELLS. Fourth Edition, Revised and Enlarged. 
 
 Demy 8vo, 250 pp., strongly bound 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' Journal. 
 
 " Characterised by extreme thoroughness. There are few owners of factories who would not 
 
 derive great benefit from the perusal of this most admirable work." Local Government Chronicle. 
 
 MODERN METROLOGY. 
 
 A Manual of the Metrical Units and Systems of the present Century. With 
 an Appendix containing a proposed English System. By Lowis D. A. 
 JACKSON, A. M. Inst. C. E., Author of " Aid to Survey Practice," &c. Large 
 crown 8vo, cloth 1 2/6 
 
 " We recommend the work to all interested in the practical reform of our weights and 
 measures." Nature. 
 
 A SERIES OF METRIC TABLES. 
 
 In which the British Standard Measures and Weights are compared with those 
 of the Metric System at present in Use on the Continent. ByC. H. DOWLING, 
 C.E. 8vo, strongly bound 1 0/6 
 
 "Mr. Dowling's Tables are well put together as a ready reckoner for the conversion of one 
 system into the other." Athenaeum. 
 
 THE IRON AND METAL TRADES' COMPANION. 
 
 For Expeditiously Ascertaining the Value of any Goods bought or sold by 
 Weight, from is. per cwt. to 1125. per cwt., and from one farthing per pound to 
 one shilling per pound. By THOMAS DOWNIE. 396 pp., leather . . 9/Q 
 
 " A most useful set of tables, nothing like them before existed." Building Nevis. 
 
 " Although specially adapted to the iron and metal trades, the tables will be found useful in 
 every other business in which merchandise is bought and sold by weight." Rail-way News. 
 
42 CROSBY LOCKWOOD &> SON'S CATALOGUE. 
 
 NUMBER, WEIGHT, AND FRACTIONAL CALCULATOR. 
 
 Containing upwards of 250,000 Separate Calculations, showing at a Glance the 
 Value at 422 Different Rates, ranging from T^th of a Penny to 20$. each, or per 
 cwt., and ^20 per ton, of any number of articles consecutively, from i to 470. 
 Any number of cwts., qrs., and Ibs., 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. Third Edition, Revised. 8vo, strongly bound . 1 8/O 
 
 "It is as easy of reference for any answer or any number of answers as a dictionary. For 
 making- up accounts or estimates the book must prove invaluable to all who have any considerable 
 quantity of calculations involving- price and measure in any combination to do." Engineer. 
 
 THE 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. Fifth Edition, carefully 
 Corrected. Royal Svo, strongly half-bound 1 5 S . 
 
 " A practical and useful work of reference for men of business generally. " Ironmonger. 
 
 "Of priceless value to business men. It is a necessary book in all mercantile offices." 
 Sheffield Independent. 
 
 THE 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 g8| per cent., 
 and Tables of Commission, &c., from to 10 per cent. By HENRY HARBEN, 
 Accountant. New Edition, Corrected. Demy Svo, half-bound . 1 5 S . 
 " A book such as this can only be appreciated by business men, to whom the saving of time 
 
 means saving- of money. The work must prove of great value to merchants, manufacturers, and 
 
 general traders." British Trade Journal. 
 
 TABLES OF WAGES. 
 
 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 THOS. GARBUTT, 
 Accountant. Square crown 8vo, half-bound 6IO 
 
 IRON=PLATE WEIGHT TABLES. 
 
 For Iron Shipbuilders, Engineers, and Iron Merchants. Containing the 
 Calculated Weights of upwards of 150,000 different sizes of Iron Plates from 
 i foot by 6 in. by J in. to 10 feet by 5 feet by i in. Worked out on the Basis of 
 40 Ibs. to the square foot of Iron of i inch in thickness. By H. BURLINSON 
 and W. H. SIMPSON. 410, half-bound "| Q Sm 
 
 MATHEMATICAL TABLES (ACTUARIAL). 
 
 Comprising Commutation and Conversion Tables, Logarithms, Cologarithms, 
 Antilogarithms and Reciprocals. By J. W. GORDON. Royal Svo, mounted 
 on canvas, in cloth case. [Just Published. 5/Q 
 
AGRICULTURE, FARMING, GARDENING, &-c. 43 
 
 AGRICULTURE, FARMING, 
 GARDENING, &c. 
 
 THE COMPLETE GRAZIER AND FARMER'S AND 
 
 CATTLE BREEDER'S ASSISTANT. 
 
 A Compendium of Husbandry. Originally Written by WILLIAM YOUATT, 
 Fourteenth Edition, entirely Re-written, considerably Enlarged, and brought 
 up to Present Requirements, by WILLIAM FREAM, LL.D., Assistant Com- 
 missioner, Royal Commission on Agriculture, 1893, Author of " The Elements 
 of Agriculture," &c. Royal 8vo, 1,100 pp., with over 450 Illustrations, 
 handsomely bound. [ Just Published. 1 11s. 60. 
 
 SUMMARY OF CONTENTS. 
 
 BOOK I ON THE VARIETIES, BREEDING, 
 REARING, FATTENING AND MANAGE- 
 MENT OF CATTLE. 
 
 BOOK II. ON THE ECONOMY AND MAN- 
 AGEMENT OF THE DAIRY. 
 
 BOOK in. ON THE BREEDING, REARING, 
 AND MANAGEMENT OF HORSES. 
 
 BOOK IV. ON THE BREEDING, REARING, 
 AND FATTENING OF SHEEP. 
 
 BOOK V. ON THE BREEDING, REARING, 
 AND FATTENING OF SWINE. 
 
 BOOK VII. ON THE BREEDING, REARING, 
 AND MANAGEMENT OF POULTRY. 
 
 BOOK VIII. ON FARM OFFICES AND 
 IMPLEMENTS OF HUSBANDRY. 
 
 BOOK IX. ON THE CULTURE AND MAN- 
 AGEMENT OF GRASS LANDS. 
 
 BOOK X. ON THE CULTIVATION AND 
 APPLICATION OF GRASSES, PULSE AND 
 ROOTS. 
 
 BOOK XI. ON MANURES AND THEIR 
 APPLICATION TO GRASS LAND AND 
 
 BOOK VI. ON THE DISEASES OF LIVE CROPS. 
 
 STOCK ! BOOK XII. MONTHLY CALENDARS OF 
 
 FARMWORK. 
 
 *** OPINIONS OF THE PRESS ON THE NEW EDITION. 
 
 " Dr. Fream is to be congratulated on the successful attempt he has made to give us a work 
 which will at once become the standard classic of the farm practice of the country. We believe 
 that it will be found that it has no compeer among the many works at present in existence. . . . 
 The illustrations are admirable, while the frontispiece, which represents the well-known bull, 
 New Year's Gift, owned by the Queen, is a work of art." The Times. 
 
 "The book must be recognised as occupying the proud position of the most exhaustive work 
 of reference in the English language on the subject with which it deals." Athenceum. 
 
 " The most comprehensive guide to modern farm practice that exists in the English language 
 to-day. . . . The book is one that ought to be on every farm and in the library of every land 
 owner. " Mark Lane Express. 
 
 "In point of exhaustiveness and accuracy the work will certainly hold a pre-eminent and 
 unique position among books dealing with scientific agricultural practice. It is, in fact, an agricul- 
 tural library of itself." North British Agriculturist. 
 
 "A compendium of authoritative and well-ordered knowledge on every conceivable branch of 
 the work of the live stock farmer; probably without an equal in this or any other country." 
 Yorkshire Post. 
 
 FARM LIVE STOCK OF GREAT BRITAIN. 
 
 BY ROBERT WALLACE, F.L.S., F.R.S.E., &c., Professor of Agriculture and 
 
 Rural Economy in the University of Edinburgh. Third Edition, thoroughly 
 
 Revised and considerably Enlarged. With over 120 Phototypes of Prize 
 
 Stock. Demy 8vo, 384 pp., with 79 Plates and Maps, cloth. . . 1 2/6 
 
 " A really complete work on the history, breeds, and management of the farm stock of Great 
 
 Britain, and one which is likely to find its way to the shelves of every country gentleman's library." 
 
 The Times. 
 
 "The latest edition of ' Farm Live Stock of Great Britain ' is a production to be proud of, and 
 its issue not the least of the services which its author has rendered to agricultural science." 
 Scottish Farmer. 
 
 " The book is very attractive, . . . and we can scarcely imagine the existence of a 
 farmer who would not like to have a copy of this beautiful and useful work." Mark Lane Express. 
 
 NOTE=BOOK OF AGRICULTURAL FACTS & FIGURES 
 
 FOR FARMERS AND FARM STUDENTS. 
 
 By PRIMROSE McCoNNELL, B.Sc., Fellow of the Highland and Agricultural 
 Society, Author of " Elements of Farming." Sixth Edition, Re-written, Revised, 
 and greatly Enlarged. Fcap. 8vo, 480 pp., leather. {Just Published. 6/O 
 
 SUMMARY OF CONTENTS : SURVEYING AND LEVELLING. WEIGHTS AND 
 MEASURES. MACHINERY AND BUILDINGS. LABOUR. OPERATIONS. DRAINING. 
 EMBANKING. GEOLOGICAL MEMORANDA. SOILS. MANURES. CROPPING. CROPS. 
 ROTATIONS WEEDS. FEEDING. DAIRYING. LIVE STOCK. HORSES. CATTLE. 
 SHEEP. PIGS. POULTRY. FORESTRY. HORTICULTURE. MISCELLANEOUS. 
 
 " No farmer, and certainly no agricultural student, ought to be without this multum-in-fiarvo 
 manual of all subjects connected with the farm." North British Agriculturist. 
 
 " This little pocket-book contains a large amount of useful information upon all kinds of agri- 
 cultural subjects. Something of the kind has long been wanted." Mark Lane Express. 
 
 "The amount of information it contains is most surprising ; the arrangement of the matter is 
 so methodical although so compressed as to be intelligible to everyone who takes a glance through 
 its pages. They teem with Information." Farm and Home. 
 
44 CROSBY LOCK WOOD 6< SON'S CATALOGUE. 
 
 BRITISH DAIRYING. 
 
 A Handy Volume on the Work of the Dairy- Farm. For the Use of Technical 
 Instruction Classes, Students in Agricultural Colleges and the Working Dairy- 
 Farmer. By Prof. J. P. SHELDON. With Illustrations. Second Edition, 
 Revised. Crown 8vo, cloth. [ Just Published. 2/6 
 
 " Confidently recommended as a useful text-book on dairy farming." Agricultural Gazette. 
 
 "Probably the best half-crown manual on dairy work that has yet been produced." North 
 British Agriculturist. 
 
 "It is the soundest little work we have yet seen on the subject." The Times. 
 
 MILK, CHEESE, AND BUTTER. 
 
 A Practical Handbook on their Properties and the Processes of their Produc- 
 tion. Including a Chapter on Cream and the Methods of its Separation from 
 Milk. By JOHN OLIVER, late Principal of the Western Dairy Institute, 
 Berkeley. With Coloured Plates and 200 Illustrations. Crown 8vo, cloth. 
 
 7/6 
 
 " An exhaustive and masterly production. It may be cordially recommended to all students 
 and practitioners of dairy science. North British Agriculturist. 
 
 " We recommend this very comprehensive and carefully-written book to dairy-farmers and 
 students of dairying. It is a distinct acquisition to the library of the agriculturist." Agricultural 
 Gazette. 
 
 SYSTEMATIC SMALL FARMING. 
 
 Or, The Lessons of My Farm. Being an Introduction to Modern Farm 
 Practice for Small Farmers. By R. SCOTT BURN, Author of " Outlines of 
 
 Modern Farming," &c. Crown 8vo, cloth 6/O 
 
 "This is the completest book of its class we have seen, and one which every amateur farmer 
 will read with pleasure, and accept as a guide." Field. 
 
 OUTLINES OF MODERN FARMING. 
 
 By R. SCOTT BURN. Soils, Manures, and Crops Farming and Farming 
 Economy Cattle, Sheep, and Horses Management of Dairy, Pigs, and 
 Poultry Utilisation of Town-Sewage, Irrigation, &c. Sixth Edition. In One 
 Vol., 1,250 pp., half-bound, profusely Illustrated . . . . "1 2/O 
 
 FARM ENGINEERING, The COMPLETE TEXT-BOOK of. 
 
 Comprising Draining and Embanking ; Irrigation and Water Supply ; Farm 
 Roads, Fences and Gates ; Farm Buildings ; Barn Implements and Machines ; 
 Field Implements and Machines ; Agricultural Surveying, &c. By Professor 
 JOHN SCOTT. In One Vol., 1,150 pp., half-bound, with over 600 Illustrations. 
 
 12/O 
 
 "Written with great care, as well as with knowledge and ability. The author has done his 
 work well ; we have found him a very trustworthy guide wherever we have tested his statements. 
 The volume will be of great value to agricultural students." Mark Lane Express. 
 
 THE FIELDS OF GREAT BRITAIN. 
 
 A Text-Book of Agriculture. Adapted to the Syllabus of the Science and 
 Art Department. For Elementary and Advanced Students. By HUGH 
 CLEMENTS (Board of Trade). Second Edition, Revised, with Additions. 
 
 i8mo, cloth 2/6 
 
 " It is a long time since we have seen a book which has pleased us more, or which contains 
 such a vast and useful fund of knowledge." Educational Times. 
 
 TABLES and MEMORANDA for FARMERS, GRAZIERS, 
 
 AGRICULTURAL STUDENTS, SURVEYORS, LAND AGENTS, 
 AUCTIONEERS, &c. 
 
 With a New System of Farm Book-keeping. By SIDNEY FRANCIS. Fourth 
 
 Edition. 272 pp., waistcoat-pocket size, limp leather . . . . "| /6 
 
 " Weighing less than i oz., and occupyingno more space than a match-box, it contains a mass 
 
 of facts and calculations which has never before, in such handy form, been obtainable. Every 
 
 operation on the farm is dealt with. The work may be taken as thoroughly accurate, the whole of 
 
 the tables having been revised by Dr. Fream. We cordially recommend it." Keif's Weekly 
 
 Messenger. 
 
 THE ROTHAMSTED EXPERIMENTS AND THEIR 
 
 PRACTICAL LESSONS FOR FARMERS. 
 
 Part I. STOCK. Part II. CROPS. By C. J. R. TIPPER. Crown 8vo, cioth. 
 
 [Just Published. 3/6 
 
 " We have no doubt that the book will be welcomed by a large class of farmers and others 
 interested in agriculture." Standard. 
 
AGRICULTURE. FARMING, GARDENING, S-c. 43 
 
 FERTILISERS AND FEEDING STUFFS. 
 
 A Handbook for the Practical Farmer. By BERNARD DYER, D.Sc. (Lond.) 
 
 With the Text of the Fertilisers and Feeding Stuffs Act of 1893, &c. Third 
 
 Edition, Revised. Crown 8vo, cloth. [Just Published. 1 /Q 
 
 "This little book is precisely what it professes to be ' A Handbook for the Practical 
 
 Farmer.' Dr. Dyer has done farmers good service in placing at their disposal so much useful 
 
 information in so intelligible a form." The Times. 
 
 BEES FOR PLEASURE AND PROFIT. 
 
 A Guide to the Manipulation of Bees, the Production of Honey, and the 
 General Management of the Apiary. By G. GORDON SAMSON. With 
 numerous Illustrations. Crown 8vo, cloth ...... "I/O 
 
 BOOK-KEEPING for FARMERS and ESTATE OWNERS. 
 
 A Practical Treatise, presenting, in Three Plans, a System adapted for all 
 Classes of Farms. By JOHNSON M. WOODMAN, Chartered Accountant. 
 Second Edition, Revised. Crown 8vo, cloth boards, 3/6 ', or, cloth limp, 2/6 
 " The volume is a capital study of a most important subject." Agricultural Gazette. 
 
 WOODMAN'S YEARLY FARM ACCOUNT BOOK. 
 
 Giving Weekly Labour Account and Diary, and showing the Income and 
 Expenditure under each Department of Crops, Live Stock, Dairy, &c., &c. 
 With Valuation, Profit and Loss Account, and Balance Sheet at the End of the 
 Year. By JOHNSON M. WOODMAN, Chartered Accountant. Second Edition. 
 Folio, half-bound ........ Net 7/6 
 
 "Contains every requisite form for keeping farm accounts readily and accurately." 
 Agriculture. 
 
 THE FORCING GARDEN. 
 
 Or, How to Grow Early Fruits, Flowers and Vegetables. With Plans and 
 Estimates for Building Glasshouses, Pits and Frames. With Illustrations. 
 By SAMUEL WOOD. Crown 8vo, cloth ....... 3/6 
 
 " A good book, containing a great deal of valuable teaching. Gardeners' Magazine. 
 
 A PLAIN GUIDE TO GOOD GARDENING. 
 
 Or, How to Grow Vegetables, Fruits, and Flowers. By S. WOOD. Fourth 
 Edition, with considerable Additions, and numerous Illustrations. Crown 
 8vo, cloth ............. 3/6 
 
 " A very good book, and one to be highly recommended as a practical guide. The practical 
 directions are excellent." Athenceum. 
 
 MULTUM=IN=PARVO GARDENING. 
 
 Or, How to Make One Acre of Land produce .620 a year, by the Cultivation 
 
 of Fruits and Vegetables ; also, How to Grow Flowers in Three Glass Houses, 
 
 so as to realise 176 per annum clear Profit. By SAMUEL WOOD, Author of 
 
 "Good Gardening, "&c. Sixth Edition, Crown 8vo, sewed . . 1/O 
 
 "We are bound to recommend it as not only suited to the case of the amateur and gentle- 
 
 man's gardener, but to the market grower." Gardeners' Magazine. 
 
 THE LADIES' MULTUM-IN-PARVO FLOWER GARDEN. 
 
 And Amateur's Complete Guide. By S. WOOD." Crown 8vo, cloth . 3/6 
 " Full of shrewd hints and useful instructions, based on a lifetime of experience." Scotsman. 
 
 POTATOES: HOW TO GROW AND SHOW THEM. 
 
 A Practical Guide to the Cultivation and General Treatment of the Potato. 
 By J. PINK. Crown 8vo .......... 2/O 
 
 MARKET AND KITCHEN GARDENING. 
 
 By C. W. SHAW, late Editor of Gardening Illustrated. Cloth . . 3/6 
 "The most valuable compendium of kitchen and markftt-earden work published." Farmer, 
 
46 CROSBY LOCK WOOD & SON'S CATALOGUE. 
 
 AUCTIONEERING, VALUING, LAND 
 SURVEYING, ESTATE AGENCY, &c. 
 
 INWOOD'S TABLES FOR PURCHASING ESTATES 
 
 AND FOR THE VALUATION OF PROPERTIES, 
 
 Including Advowsons, Assurance Policies, Copyholds, Deferred Annuities, 
 Freeholds, Ground Rents, Immediate Annuities, Leaseholds, Life Interests, 
 Mortgages, Perpetuities, Renewals of Leases, Reversions, Sinking Funds, 
 &c., &c. 25th Edition, Revised and Extended by WILLIAM SCHOOLING, 
 F.R.A.S., with Logarithms of Natural Numbers and THOMAN'S Logarithmic 
 Interest and Annuity Tables. 336 pp., Demy 8vo, cloth. 
 
 \. Just published. Net 8/O 
 
 " Those interested in the purchase and sale of estates, and in the adjustment of compensation 
 cases, as well as in transactions in annuities, life insurances, &c., will find the present edition of 
 eminent service. " Engineering. 
 
 "This valuable book has been considenbly enlarged and improved by the labours of 
 Mr. Schooling, and is now very complete indeed." Economist. 
 
 " Altogether this edition will prove of extreme value to many classes of professional men in 
 saving them many long and tedious calculations." Investors' Review. 
 
 THE APPRAISER, AUCTIONEER, BROKER, HOUSE 
 
 AND ESTATE AGENT AND VALUER'S POCKET ASSISTANT. 
 
 For the Valuation for Purchase, Sale, or Renewal of Leases, Annuities, and 
 
 Reversions, and of Property generally ; with Prices for Inventories, &c. By 
 
 JOHN WHEELER, Valuer, &c. Sixth Edition, Re-written and greatly Extended 
 
 by C. NORRIS, Surveyor, Valuer, &c. Royal 321110, cloth . . . 5/Q 
 
 "A neat and concise book of reference, containing an admirable and clearly-arranged list of 
 
 prices for inventories, and a very practical guide to determine the value of furniture, &c." Standard. 
 
 " Contains a large quantity of varied and useful information as to the valuation for purchase, 
 
 sale, or renewal of leases, annuities and reversions, and of property generally, with prices for 
 
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AUCTIONEERING, VALUING, LAND SURVEYING, &-c. 47 
 
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