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By Arthur Winslow

Introductory.—The following paper is based upon a report on the lead- and zinc- deposits of Missouri, prepared for the State Geological Survey, which is now being printed. This report is the outcome of work prosecuted by the writer, assisted by Mr. J. D. Robertson, during the past five years. The studies in the State were supplemented by examinations of the similar ore deposits in Wisconsin and Arkan- sas. The report will contain in all about 800 pages, and the aim has been to make it complete and exhaustive, especially in descriptive matter. Naturally, only a brief outline can be presented here, and the reader is referred to the report itself for further details. Contents. I.—History and Statistics, . . 636 II.—Topography of the Region, . 639 III.—General Geology, . . .639 The Archean, . . .639 The Algonkian, . . 640 The Silurian, . . .640 The Devonian, . . 640 The Lower Carboniferous, 641 Tie Coal Measures, . 641 The Tertiary, . . .641 Structural Geology,. . 642 IV.—The Ore-Deposits, . . .643 Geologic Distribution, . 643 The Forms of the Ore-Bodies, . . .641 The Composition if the Ore-Bodies, . . .645 Gangues, . . . 645 Minerals, . . .618 Paragenesis of Minerals, . . . 651 The Structure of the Ore-Bodies, .... 651 V.—Descriptions of Types, . . 652 The Eagle Mines, . . 652 Shaft No. 23, . . 652 The Western Zinc Company or Oswego Lands, 651 The Gobar and Tomlinson Shaft, . 655 The Alba Company's Mine, 656 The Victor Mine, . . 658 The Bonne Terre Mines, . 660 General Geology, . 660 The Ore-Bodies, . 661 The Vallé Mines, . . 664 The Garatee Mines, . 664 The Corn-Stalk Diggings, . . .665 The Virginia Mine, . 666 The Conlogue Mine, . 667 VI.—The Mode of Formation of the Ore-Bodies, . . 670 The Formation of the Cavities. . . . 670 The Filling of the Cavities, . . . .675 The Formation of the Breccia Deposits, . . 673 The Formation of Circle Deposits, . . .674 The Impregnated Deposits of the Southeast, . 676 VII.—The Origin of the Metalliferous and Other Minerals, 676 1. Originally Deposited in Concentrated Condition, 676 2. Derived from Great Depths, . . .677 3. Original Diffusion, Supplemented by Lateral Secretion, . . . 678 4. Concentrated Through Surface Decomposition, 681

Jan 1, 1895

Ninetecn papers and a round table. as follows: The Future of the American Iron and Steel Industry (Howe memorial Lecture), by Zay Jeffries; Rote of Carbon Elimination and Degree of Oxidation of metal Hath in Isasic Open-hearth Practice. 11, by ,Alexander L. Feild; A New Method for determining lron Oxide in Liquid Steel, by C. H. Herty. Jr., J. M. Gaines. Jr., H. Freeman and M. W. Lightner; I'racticsl Obarrvntions on Manufacture of basic Open-hearth, High-carbon Killed Steel, by W. J. Itcagan; Production of Gray lron from steel Scrap in the Electric Furnace, by T. F. Baily; reclaim ing Steel-foundry Sanda, by A. H. Dierker; Influence of Rate of Cooling on Dendritic Structure and Microstructure of Some Hypocutectoid Steel, by Albert Sauveur and C. H. Chou; Transformation of Austcnite at Constant Subcritiral Temprratures, by I?. S. Dnvenport and E. C. Bain; Progress Notes on the Iron-silicon Equilibrium Diagram, by Bradley stoughton and S. Greiner; Influence of Nitrogen on Special Steels and Some Experiments on Case-hardening with Nitrogen; by Shun-ichi Satoh; Production and Some properties of Large Iron Crystals, by N. A. Ziegler: Tensile Properties of Rail and Other Steels at Elevated Temperatures, by John R. Freeman, Jr. and G. Willard Quick; Endurance Properties of Steel in Steam, by T. S. Fullcr; Development of Casing for Deep Wells; a Study of Structural Alloy Steels, by F. W. Bremmer; Electrolytic Iron from Sulfide Ores. by Robert D. Pike, George H. West, L. V. Steek, Ross Cummings and B. P. Littlc; Sintering Limonitic Iron Ores at Ironton, Minnesota, by Perry G. Harrison; Concentration of the mesabi Ilematites, by E. W. Davia; Resistance of Iron Ores to Decrepitation and Mechanical Work, by T. L. Joseph and E. P. Barrett; Experiments Demonstrate Method of Producing Artificial Manganese Ore, by T. L. Joseph, E. P. Barrett and C. E. Wood; Iron Ore Round Table.

Jan 1, 1930

By R. J. Anderson

Roughly, a crack in a casting may be considered, for the moment, to be due to fracture of the alloy resulting from the stress set up by the contraction in volume on passing from the liquid to the solid state. Cracks may be external or surface, internal or deep-seated, or incipient or so-called strain cracks. Draws may appear as depressions, unevenness, and "pinching in" of the surface of a casting. Roughly, draws are due to contraction in volume and are governed largely by the same factors as cracks. A casting may be cracked, however, without being drawn. Shrinkage is a foundry term and refers to the contractio~l in volume of a metal or alloy on passing from the liquid to the solid state. Patternmaker's shrinkage is the total contraction in volume (including liquid, solidification, and solid shrinkage) that occurs when an alloy is poured into a mold. The contraction in volume of aluminum is one of the principal factors affecting the occurrence of cracks, as will be shown later, and the question of shrinkage and its control requires careful study in any treatment of cracking in castings. In the case of sand and die castings, cracks have been attributed to a number of causes, but in the case of most light aluminum alloys, they are due to the large contraction in volume on freezing and the lack of its regulation or control. The most important factors are: (1) Contraction in volume; (2) composition of alloy; (3) quality of melting charge; (4) design of casting; (5) method of molding; (6) hardness of ramming; (7) method of gating; (8) hardness and characteristics of cores; (9) chills; (10) risers; (11) melting temperatures; (12) furnace used for melting; (13) pouring temperatures; (14) inclusions in alloys; (15) hot shortness of alloys; and (16) physical properties of alloys at high temperatures. Of these, the first, second, third, and eleventh to sixteenth involve ascertainable metallurgical facts; the remainder are largely matters of opinion, judgment, and technical knowledge of men experienced in the production of castings.

Jan 1, 1923

By John Mathews

IT is a great honor to be asked by. the Board of Directors of this Institute to deliver the Henry Marion Howe lecture. The invitation carries with it a great responsibility, which I accept with considerable hesitation and with a feeling of unworthiness to perform the duties expected of me in this hour devoted to the memory of the life, character, and work of the late Professor Howe. Many of you recall the scholarly address delivered here a year ago by Prof. Albert Sauveur, and the beautiful tribute he paid-to his friend and colleague of many years in the great work of changing the art of iron making into the science of iron. My association with Professor Howe, was of brief duration-only one year-and the relation was that of pupil to teacher. My feeling toward him in later years was always that of a humble disciple at the feet of a master. He attained his third academic degree in the year that I was born. I recall the pride I felt when, after entering the, steel industry, I received from him, from time to time, letters asking for information or, perchance, asking my opinion, and he was always most punctilious in acknowledging the source of such bits of information in his writings. It was also my good fortune to sit at the feet of another great teacher-Sir William Roberts-Austen, at the Royal School of Mines. I mention him because his name was used by Osmond in coining the word "austenite," which is the subject of this address, and Osmond's suggestion was heartily approved by Howe. These three international metallurgists were the best of friends and delighted to honor the achievements of one another. There are other reasons for mentioning Roberts-Austen at this time. It was an introduction from Howe that opened to me the door of his -laboratory as well as of his heart. It was while at Roberts-Austen's laboratory that I .worked side by side with William Campbell

Jan 4, 1925

By John A. Mathews

It is a great honor to be asked by the Board of Directors of this Institute to deliver the Henry Marion Howe lecture. The invitation carries with it a great responsibility, which I accept with considerable hesitation and with a feeling of unworthiness to perform the duties expected of me in this hour devoted to the memory of the life, character, and work of the late Professor Howe. Many of you recall the scholarly address delivered here a year ago by Prof. Albert Sauveur, and the beautiful tribute he paid to his friend and colleague of many years in the great work of changing the art of iron making into the science of iron. My association with Professor Howe was of brief duration—only one year—and the relation was that of pupil to teacher. My feeling toward him in later years was always that of a humble disciple at the feet of a master. He attained his third academic degree in the year that I was born. I recall the pride I felt when, after entering the steel industry, I received from him, from time to time, letters asking for information or, perchance, asking my opinion, and he was always most punctilious in acknowledging the source of such bits of information in his writings. It was also my good fortune to sit at the feet of another great teacher— Sir William Roberts-Austen, at the Royal School of Mines. I mention him because his name was used by Osmond in coining the word "aus-tenite," which is the subject of this address, and Osmond's suggestion was heartily approved by Howe. These three international metallurgists were the best of friends and delighted to honor the achievements of one another. There are other reasons for mentioning Roberts-Austen at this time. It was an introduction from Howe that opened to me the door of his laboratory as well as of his heart. It was while at Roberts-Austen's laboratory that I worked side by side with William Campbell

Jan 1, 1925

By H. S. Rawdon

One of the most vital problems in the manufacture of steel at present is the occurrence of the defects that have been popularly termed "snow flakes," "flakes," or "scabs." Particularly is this the problem of many manufacturers who, during the past 2 yr., have undertaken large-scale production for the first time. A study of the microstructure of such defective material throws considerable light upon the nature of these defects and is essential before measurcs may be taken for the elimination of the defects. Flakes do not appear to be found in the plain carbon steels; they have been found. however, in abundance in some of the simple alloy steels that are being used in such vast quantities; vie., nickel steel of the approximate composition, 0.40 carbon and 3.5 per cent. nickel, and in the chrome-nickel type. The present article summarizes the characteristic features of defective steel of the flaky type as they have been found by laboratory study of numerous specimens, and it aims to show the conditions within the metal that are favorable to the occurrence of this type of defect without entering into the details of mill practice (size of ingot, design of molds, rate of cooling, distribution of cooling stresses, etc.), all of which conditions appear to play a role in the production of these defects. MacrostrUctURe To one familar with flaky steel, the appearance of "snow-flakes" is unmistakable and is not to be confused with other types of defects. Figs. 1 to 6 show the appearance of fractures of steel showing this type of defect; the white silvery area, which always has the appearance of being of a very coarsely crystalline structure, in the specimen stands out in bold contrast to the darker background and readily justifies the use of the term "snow-flakes." Fig. 1 shows the appearance of the faces of the two halves of a nickel-steel forging that has been split to show the interior flakes. Fig. 2 is a nickel-steel bar (carbon 0.40 per cent.,

Jan 1, 1920

By W.M. Peirce

The present work has been done in an endeavor to correlate and complete the data on the constitution of alloys of zinc with other common metals, dealing exclusively, however, with the zinc-rich alloys in which the zinc content is between 90 and 100 per cent. This investigation has included the systems lead-zinc, cadmium-zinc, iron-zinc, copper-zinc, aluminum-zinc, nickel-zinc, manganese-zinc, cobalt-zinc, tin-zinc, and magnesium-zinc. The important ternary system zinc-lead-cadmium and the zinc corners of other ternary systems have been investigated in connection with this work but will not be dealt with here. Zinc does not form a single homogenous zinc-rich solid solution over any considerable range of concentration with any of the metals mentioned. A limited range of solid solubility is said, by previous investigators, to occur in several cases and certain effects on the properties of zinc are attributed (with varying degrees of consistency among different writers) to the presence of certain other metals dissolved in zinc. The increasing use of rolled zinc and the possibilities offered by zinc as a casting alloy in certain fields have made it essential to determine precisely these equilibrium relationships. In carrying out this investigation reliance was placed chiefly on two methods, conductivity measurements and microscopic analysis. The first method proved valuable in determining the existence and extent of solid solubility. The second method stands alone as a means of determining structural characteristics and supplements the first method in the measurement of solid solubility. The scleroscopic hardness of all conductivity specimens was measured partly for its value from the point of view of mechanical properties and partly as a check on the conductivity curves in indicating the limits of solid solubility. No hardness curves are included in this paper, for in no case were they important in arriving at the constitution of any system. Conductivity measurements were in all cases made on cold-rolled strips 0.020 in. thick and 0.5 in. wide, both as cold rolled and after an

Jan 1, 1923

By Robert Anderson

ROUGHLY, a crack in a casting may be considered, for the moment, to be due to fracture of the alloy resulting from the stress set up by the contraction in volume on passing from the liquid to the solid state. Cracks may be external or surface, internal or deep-seated, or incipient or so-called strain cracks. Draws may appear as depressions, unevenness, and "pinching in" of the surface of a casting. Roughly, draws are due to contraction in volume and are governed largely by the same factors as cracks. A casting may be cracked, however, without being drawn. Shrinkage is a foundry term; it connotes the contraction in volume of a metal or alloy on passing from the liquid to the solid state. Pattern-makers' shrinkage is the total contraction in volume (including liquid, solidification, and solid shrinkage) that occurs when an alloy is poured into a mold. The contraction in volume of aluminum is one of the principal factors affecting the occurrence of cracks, as will be shown later, and the question of shrinkage and its control requires careful study in any treatment of cracking in castings. In the case of, sand and die castings, cracks have been attributed to a number of causes, but in the case of most light aluminum alloys, they are due to the large contraction in volume on freezing and the lack of its regulation or control. The most important factors are: (1) Contraction in volume; (2) composition of alloy; (3) quality of melting charge; (4) design of casting; (5) method of molding; (6) hardness of ramming; (7) method of gating; (8) hardness and characteristics of cores; (9) chills; (10) risers; (11) melting temperatures; (12) furnace used for melting; (13) pouring tempera-tures; (14) inclusions in alloys; (15) hot shortness of alloys; and (16) physical properties of alloys at high temperatures. Of these, the first, second, third, and eleventh to sixteenth involve ascertainable metallurgical facts; the remainder are largely matters of opinion, judgment and technical knowledge of men experienced in the production of castings.

Jan 10, 1921

By W. M. Peirce

The present work has been done in an endeavor to correlate and complete the data on the constitution of alloys of zinc with other common metals, dealing exclusively, however, with the zinc-rich alloys in which the zinc content is between 90 and 100 per cent. This investigation has included the systems lead-zinc, cadmium-zinc, iron-zinc, copper-zinc, aluminum-zinc, nickel-zinc, manganese-zinc, cobalt-zinc, tin-zinc, and magnesium-zinc. The important ternary system zinc-lead-cadmium and the zinc corners of other ternary systems have been investigated in connection with this work but will not be dealt with here. Zinc does not form a single homogenous zinc-rich solid solution over any considerable range of concentration with any of the metals mentioned. A limited range of solid solubility is said, by previous investigators, to occur in several cases and certain effects on the properties of zinc are attributed (with varying degrees of consistency among different writers) to the presence of certain other metals dissolved in zinc. The increasing use of rolled zinc and the possibilities offered by zinc as a casting alloy in certain fields have made it essential to determine precisely these equilibrium relationships. In carrying out this investigation reliance was placed chiefly on two methods, conductivity measurements and microscopic analysis. The first method proved valuable in determining the existence and extent of solid solubility. The second method stands alone as a means of determining structural characteristics and supplements the first method in the measurement of solid solubility. The scleroscopic hardness of all conductivity specimens was measured partly for its value from the point of view of mechanical properties and partly as a check on the conductivity curves in indicating the limits of solid solubility. No hardness curves are included in this paper, for in no case were they important in arriving at the constitution of any system. Conductivity measurements were in all cases made on cold-rolled strips 0.020 in. thick and 0.5 in. wide, both as cold rolled and after an

Jan 1, 1923

By Albert Sauveur

THE senior author of this paper has expressed the belief that when gamma iron transforms into alpha iron on reaching the A3 point, each gamma grain does not change bodily into one or more alpha grains but that the alpha phase forms first at the boundaries and along the crystallographic planes of the austenite grains.1 To quote: On cooling through the point A, at about 900° C., iron passes from the gamma condition to a. new allotropic form generally designated as alpha. This transforma¬tion, however, is not instantaneous. There are good reasons for believing that it begins at the grain boundaries and along the octahedral planes of the crystals and that it progresses until each grain of gamma iron is changed into a grain of alpha iron, the resulting structure being similar to that of gamma iron. Were it possible to retain at room temperature pure iron but partially transformed, it seems probable that a Widmanstättian structure, or rather, as later explained, a martensitic structure would be observed (Fig. 1), consisting of alpha iron at the boundaries and at the octahedral planes, and of a groundmass of gamma iron. In order to confirm, if possible, the accuracy of that view, a number of experiments were conducted. Polished samples of electrolytic iron were heated in a vacuum, maintained in the gamma range for several hours and quenched in different media. It was hoped by such means to produce and retain on the polished surfaces a pattern which would reveal the mechanism of the allotropic transformation. The samples were placed in evacuated quartz tubes, heated to 1000° C. and held 2 hr. at that temperature. The tubes were then immersed in the quenching bath. Iced brine and liquid air were used first. The polyhedral austenitic structure existing at the time of immersion was very clearly revealed (Fig. 2). This is generally ascribed to iron volatilizing at the grain boundaries.

Jan 1, 1929

By Zay Jeffries

Tungsten has the highest melting point of all the known metals, namely 3350 C.; it is one of the hardest of the metals; it has the highest equiaxing or recrystallization temperature after strain hardening, of any pure metal known. It is particularly distinguished because, when composed of small equiaxed grains, it is extremely brittle and fragile at room temperature, and when possessing a fibrous structure it may be ductile and pliable at room temperature. The common ductile metals act in exactly the opposite manner in this respect. The present paper will include a brief note regarding the manufacture of wrought and ductile tungsten. The metallography of wrought and ductile tungsten in the various stages of manufacture will be considered more or less in detail. The general relationships between the properties of tungsten and other metals will also be considered. A discussion will be given explaining why fibrous tungsten is ductile at room temperature, even though past experience with other metals would indicate that it should be brittle. Finally, a brief note regarding some new fundamental metallographic propositions relating to all metals will be given. Manufacture of Wrought and Ductile Tungsten Up to about 10 years ago, it had not been possible to work tungsten mechanically. About the year 1908, Dr. William D. Coolidge, of the General Electrie Go., produced ductile tungsten from what was then supposed to be an inherently brittle metal and which, in fact, was inherently brittle in its normal state, that is, when composed of equiaxed grains. Since that time many products, chief among which are the filaments for electric incandescent lamps, have been made from wrought and ductile tungsten. Tungsten is produced chiefly from the minerals wolframite and scheelite.1-8 The ores may be reduced in many ways. For example, the ore may be fused with alkali carbonates and the fusion dissolved in water; sodium tungstate is formed, which is soluble in water. This

Jan 1, 1919

By C. R. Austin

THE paper describes an investigation on the pressure welding of low-carbon steels. The work necessitated a reproducible mechanical means of making the weld and also a test that would indicate the nature and completeness of the union. An apparatus including a high-temperature furnace was devised for making the welds, and the ordinary tensile pulling test 'in correlation with macroscopic and microscopic observations was used as a means of examining the result. Initially it was intended to devise some simple test of weldability, but as the experimental work progressed, it soon became clear that with our limited knowledge of the exact nature of the mechanism of pressure welding it was impossible to interpret our results or to devise a simple test of weldability. Hence it was manifestly necessary first to study the mechanism of such welding and attempt to elucidate the fundamentals underlying the so-called welding of steel by pressing together two metal surfaces. It also became evident that it was necessary to define the term "welding." In many early experiments when, two heated rods were pressed together and then pulled in the cold, very high tensile values were obtained, and yet the fracture took place exactly in the line of junction except for a few small scattered areas. In other words, the' rods pulled apart just as they were before being "stuck" together and had certainly not welded completely, despite the high value indicating the strong cohesive force operating. In this paper, welding has been considered as a form of intimate contact between two metal surfaces, so that the units lose their individual identity and there is no change in physical properties in passing through the weld from one unit to the other. This is defined as "true welding." When true welding has taken place completely over the whole section, the probability is that the rupture in tensile test will occur outside the weld.

Jan 1, 1932

By F. C. Langenberg

IT is the purpose of this paper to present a limited amount of experimental data obtained on the Charpy impact machine. Several concrete examples will be given showing the relation existing between the results obtained upon the Charpy impact machine and the behavior of the parts tested when in service. Although it is pointed out by G. Charpy and A. Cornu-Thenard1 that it is first necessary to determine a satisfactory working process before studying the correlation between the results of these tests and the behavior of the parts tested in service, this ideal course cannot be strictly adhered to. If a certain part repeatedly fails in service and the available tests give no indication of its cause, advantage must be taken of any possible means that will solve the problem; therefore, even though the reliability of the results obtained by the Charpy impact machine have been questioned by many, it was necessary to use this instrument without giving careful consideration to its possible sources of error. It would seem that the conclusions arrived at by Charpy and Cornu-Thénard justify the assumption that the precision obtained by this machine is comparable to that obtained by, the other more common forms of testing. The second general conclusion arrived at by them, namely, that the impact test upon notching does not offer any direct correlation to the ordinary tests, is also borne out by many hundred determinations made in the laboratories at Watertown Arsenal. This statement, however, should be qualified as follows: Other ordinary tests include the static tensile test from bars taken in a longitudinal .direction and the Brinell hardness. The author agrees that no law is yet known for the computation of the energy absorbed in the rupture of bars of the same material but of different dimensions. Although Charpy and Cornu-Thénard do not refer in their valuable article to the use of the Charpy machine in industrial practice, it should be stated that this instrument has been in constant use in the laboratory at Watertown Arsenal for several

Jan 8, 1919

By D. Hanson

Fox most of their practical applications metals are required to with-stand stresses of appreciable magnitude: indeed, it is because they possess the quality of resisting stress without becoming permanently deformed that they find such extensive use in the service of man. Metals and alloys must, in service, usually behave as elastic substances-or nearly so. It is not difficult to satisfy this condition at ordinary temperatures. Iron and its alloys, especially the steels, are at normal temperatures excellent elastic bodies, capable of satisfying most of the mechanical requirements of the engineer: where electrical, chemical or other properties are impor-tant, which cannot be met by steels, it is usually possible to find a non-ferrous alloy such as nickel, copper or aluminum, which will prove satisfactory. When the metals or alloys are not inherently sufficiently elastic, cold-working or heat-treatment may develop elastic properties to a sufficient extent for practical needs. By means of relatively simple, rapid tests we can measure such properties as elastic modulus, limit of proportionality and proof stress, upon which design can be based with confidence. The case of the soft metals, such as lead and tin, is well known to be exceptional. They possess no definite limit of elasticity, and the value of proof stress or tensile strength depends to a great extent on the speed with which the test is carried out. Design here must be based on other considerations than a well-established theory of the proportionality of stress and strain. It is now generally recognized that steels and non-ferrous alloys possess at temperatures not greatly exceeding that of the atmosphere, characteristics quite different from those existing at ordinary temperatures, and that they assume qualities similar to those of the soft metals. Not only have they no limit of elasticity, but the proof stress and the ultimate stress depend on the time of application of the load. Flow under load may persist for long periods of time, possibly indefinitely, and the determination of a true maximum stress becomes a matter of great difficulty.

Jan 1, 1939

By W. M. Pierce

THE present work has been done in an endeavor to correlate and complete the data on the constitution of alloys of zinc with other common, metals, dealing exclusively, however, with the zinc-rich alloys in which the zinc content is between 90 and 100 per cent. This investigation has included the systems lead-zinc, cadmium-zinc, iron-zinc, copper-zinc, aluminum-zinc, nickel-zinc, manganese-zinc, cobalt-zinc, tin-zinc, and magnesium-zinc. The important ternary system zinc-lead-cadmium and the zinc corners of other ternary systems have been investigated in connection with this work but will not be dealt with here. Zinc does not form a single homogenous zinc-rich solid solution over any considerable range of concentration with any of the metals mentioned. A limited range of solid solubility is said,; by previous investigators, to occur in several cases and certain effects on the properties of zinc are attributed (with varying degrees of consistency among different writers) to the presence of certain other metals dissolved in zinc. The increasing use of rolled zinc and the possibilities offered by zinc as a casting alloy in certain fields have it made essential to determine precisely these equilibrium relationships. In carrying out this .investigation reliance was placed chiefly on two methods, conductivity measurements and microscopic analysis. The first method proved valuable in determining the existence and extent of solid solubility. The second method stands alone as a means of determining structural characteristics and supplements the first method in the measurement of solid solubility. The scleroscopic hardness of all conductivity specimens was measured partly for its value from the point of view of mechanical properties and partly; as a check on the conductivity curves in indicating the limits of solid solubility. No hardness curves are included in this paper, for in no case were they important in arriving at the constitution of any system.

Jan 2, 1922

By Dever C. Ashmead

Anthracite was first mined in the Wyoming Valley and sold as an article of commerce in 1808. As some preparation has always been necessary to make it ready to burn, the preparation of anthracite must date back over a hundred years. Two vital factors have determined to a large extent the degree and the method of anthracite preparation. These are, first, the character of the beds worked and the methods by which they are mined and, second, the equipment used and practices followed in the burning of the coal. It is not the intention here to go deeply into these phases of preparation as a paper of no mean length could be prepared on the history of either. Rather, the intention here is to point out the main considerations and to show the influence they have exerted on the preparation of anthracitc. Mining Methods and Their Relation to Preparation In the beginning of the nineteenth century, the coal beds were virgin with the possible exception of some outcroppings that had been worked, to a slight extent, by the Indians. It is known that the American aborigines had a, knowledge of the use of this fuel, because when the Wyoming Valley was purchased from them, in 1754, they mentioned the fact that, by selling the land, they would lose their coal. Real mining of anthracite began about 1808 when Judge Jesse Fell, of Wilkes-Barre, discovered that the "common stone coal of the valley" could be burned in an open grate. For some years thereafter mining was conducted near the surface. The working p1aces were driven narrow; only the best of the coal was selected and the remainder was left in the ground. Only the lumps could be used, as no market existed for other sizes. As time passed, however, it became necessary either to go farther into the ground or to widen the working places. When these places were widened, falls of roof were apt to occur, making it necessary

Jan 1, 1922

By Charles Clayton

IN connection with certain coöperative work carried on between the Ordnance Department of the U. S. Army, the U. S. Bureau of Mines, and the U. S. Geological Survey during the year 1918, it was the writers' privilege to make metallographic examinations of a great many test bars and other pieces of nickel-steel gun forgings. The material studied came from many different steel plants throughout the country and consisted both of forgings that had been accepted by the Ordnance Department and those that had failed to pass the specified physical tests. In general, these tests require a minimum tensile strength of 95,000 lb. (42,091 kg.), an elastic limit of 65,000 lb. (29,483 kg.), an 18 per cent. elongation, and a 30 per cent. reduction in area. An average chemical composition of the steel studied is 0.38 per cent. carbon and 2.9 per cent. nickel. The steel was of both basic electric and basic open-hearth manufacture. The object of the metallographic work was two-fold: to assist in detecting defects in the steel and, if possible, to suggest remedies for the same; and to obtain as much information as possible in regard to the relation of the microstructure of the metal to its physical properties. The greater part of the investigation was devoted to defective metal that failed to pass the ordnance specifications. Many types and kinds of more or less serious defects thus came under observation, but most of these were due to the attempts by the manufacturer to meet the enormous demand for ordnance steel with more or less inadequate equipment, and were soon remedied. Two defects, the so-called "flakes" or "snowflakes" and a certain "fibrous" or "woody" fracture, were encountered so frequently and were so disastrous to the steel that the greater part of the study was devoted to them. As a result much information as to their nature and their effects

Jan 2, 1919

By H. B. Pulsifier

The following report on the structure of copper is the result of work done in the laboratory of the Rome Wire Co. early in 1925. Previous work had indicated to the author that excellent results might be expected if a suitable technique in surfacing and etching could be developed. The resources of the Rome Wire Co. enabled this metal to be studied more intensively than previously, although none of the materials were investigated exhaustively. The material presented is hardly more than a preliminary summary of the most obvious character of the metal; a much longer research would have been necessary to solve many of the pressing problems connected with the casting and working of copper. The Rome Wire Co. has generously released the paper; to Dr. E. H. Darby, technical supervisor of the company, are due particular thanks for his appreciation of the importance of metallographic study of copper and for his effective support in the prosecution of the work and in making its publication possible. Dendrites, Cells and Granules The microscope reveals at least three orders of structural units in copper, as in other metals. The largest structural units are the dendrites —spine-shaped crystals building up the masses of metal when it solidifies from a melt or is crystallized from solutions by chemicals or electricity. The nucleus cells, commonly called "grains," are the largest and most conspicuous units of recrystallized solid metal; the limitations of their growth usually confine their sizes to microscopic proportions, although in "single crystals" they may become as large as the piece of metal itself. The granules are the microscopic fine-structural blocks or laminations that build up the nucleus cells; they are revealed when metal is etched with suitable chemicals. The granules are commonly visible at 500 diameters magnification and are plainly visible at 1000 diameters; magnification of the granular surfaces up to 6000 to 9000 diameters shows no finer units, not because of lack of optical resolution but because the chemical attack has left an unfeatured smooth surface.

Jan 1, 1926

By F. S. McNicholas, M. S. Walker, V. C. Rogers

During the year of 1944 and the first half of 1945, the Climax Molybdenum Co. made a study of some of the problems in block and panel caving, with the use of a scale model. The experiments dealt essentially with the type of rock and conditions at Climax, but some experiments were carried out to simulate conditions found in other mines. Most of the previous experiments on the caving characteristics of rock have dealt with sedimentary or broken igneous material. The series of experiments described here was designed to show the caving action of unbroken igneous rock. Con- siderable difficulty was experienced in duplicating unbroken material in the model. The results obtained are believed to be relatively correct, but verification must necessarily come from future mine operation. Observations in the mine and glory hole, together with statistical data, were used as criteria for creating similar conditions in the model. In 1913, George R. Lehman' experimented with broken material in a model for the Inspiration Consolidated Copper Co. and, more recently, P. B. Bucky2 experimented with broken material with a capping of mill tailings. Mr. Lehman's model represented a maximum ore height of 70 ft. capped by 55 ft. of waste. He varied the draw-hole spacing from 6¼ ft. to 8? ft. and 12½ ft. The material used graduated from fines to 30-in. maximum size. Some of his conclusions were: "(I) The less the distance between chute centers, the greater the extraction (Fig. I); (2) the higher the ore column, the greater the extraction; (3) the less the amount drawn at a time from each chute, uniformly, the greater the extraction of clean ore before the capping appeared, but not the greater the total extraction to a I per cent copper final product." (Fig. 2.) Professor Bucky concluded, in part: "(I) Drawing of ore may take place at any time from any finger and in any amount without affecting materially: (a)

Jan 1, 1946

By William Priestley

The author has shown, by .practical experiments, how the rate of cooling steel in the mold governs ingotism, segregation, the formation of dendrites, and the distribution of intergranular material; and the resulting effect these conditions have on the physical qualities of the steel before annealing, after annealing, and after forging. The paper also describes how the structure of steel is affected by the design of the mold and the method of pouring. It is shown that the various constituents of carbon steel segregate differently under different rates of cooling. For the classes of steel covered in this paper, it is concluded that the best physical structure and the most uniform chemical composition is obtained by pouring the steel at a low temperature and solidifying as rapidly as possible in the mold. MUCH time has been devoted, by metallurgists, to the study of steel after solidification and remarkable strides have been made in the heat treatment of steel, but less knowledge is available of the thermophysical, activity of the constituents of steel prior to solidification in the mold. It is known that certain elements added to steel produce marked changes in physical properties, also that other elements added to steel produce similar changes, but we have only meager knowledge as to how these elements combine in steel under different conditions of solidification. It is not sufficient to know, from chemical analysis, that a certain element is present in steel. We should know how this element is in combination with the other elements and whether the combination is such as will give the greatest physical properties. Certain elements go into solid solution with the iron, while others segregate to the grain boundaries and combine with the impurities collected there. Until it is known where an alloy produces the most beneficial effect and a means, is determined for controlling its physical location by altering solidification conditions, or otherwise, we will not obtain the maximum value from our alloys.

Jan 2, 1924