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By V. K. Zworykin

THROUGHOUT its development the science of electronics, like so many other branches of science and industry, has been indebted to the metallurgist. Metallurgy has provided the electronic engineer with conductors to furnish passage for electrons outside of his evacuated tubes; it. has developed tungsten and tantalum wires for emitting electrons and various refractory metals and alloys suitable for electrodes, which receive them and guide them within the tube; finally it has supplied ferromagnetic materials both for shielding electronic apparatus from magnetic fields and for forming highly concentrated fields for deflecting electron. Today I hope to show you that electronics has not been altogether ungrateful for this assistance. More specifically, I wish to indicate the role that the electron microscope, a relatively recent product of electronic engineering, is playing even now in the study of metals. Every metallographer is aware that his standard metallographic microscope will not reveal structural detail involving separations smaller than a certain fraction -at the very best a tenth-of a micron. This limitation, he knows, is a consequence of the fact that the wave length of the light employed for forming the image has this order of magnitude. It is, thus, a property of all light microscopes. To overcome it, a different imaging medium must be employed. The existence of such a medium became evident when it was demonstrated' that electrons were affected by magnetic and electric fields with axial symmetry just as light is affected by glass lenses; these fields, or "electron lenses," curve the paths of electrons reaching them from an object located on the axis of symmetry in such a manner that, at some distance from the lens, a true image of the object is formed, Furthermore, although a wave length may be ascribed to electron beams just as to light, this wave length is much shorter; for electrons accelerated through a difference of potential of 50 kilovolts, the wave length is only about one hundred-thousandth of that of visible light: Actually, the electron microscopes of today resolve detail one hundred times as fine as light microscopes; if the maximum useful magnification of the latter is taken to be a thousand, that of electron microscopes is one hundred thousand. THE ELECTRON MICROSCOPE Since electrons are readily scattered and absorbed by matter, specimens to be observed in the electron microscope must be prepared to be less than one micron in thickness; furthermore, the interior of the microscope must be carefully evacuated to prevent collisions between the electrons and the molecules of the air. Finally, as already mentioned, the lenses are formed by axially symmetric magnetic or electric fields, and not by any material medium such as glass. Apart from these basic differences, the electron microscope closely

Jan 1, 1943

By Jorge Munoz Reyes

There are three main oil areas in Bolivia (Fig. 1) although so far only one has yielded petroleum in commercial quantities. The Sub-Andean zone is along the easternmost ranges of the Andes, bordering the large eastern and northeastern lowlands. It extends from the Peruvian frontier, north of Lake Titicaca in a southeasterly direction towards the city of Santa Cruz and from there southward to the Argentine border. This zone forms a belt about 1200 km. long by 100 km. wide, and comprises a series of parallel, very rugged, low ranges. Oil has been known and utilized by the natives in these regions since colonial times, from the large number of seepages, which in modern times have led to the discovery of many fields. The second oil zone of Bolivia lies along the eastern and southern borders of Lake Titicaca, on the Andean high plateau, at an average altitude of 13,000 ft. above sea level. It comprises an area of approximately one million hectares (2,470,000 acres). Several seepages are known here, but little development has taken place, because of the difficulties encountered, as the greater part of the territory is covered by volcanic tuffs and ashes, which conceal the structure underneath. The third area is called the "Central zone," and is in the heart of the country, in the Department of Cochabamba, covering approximately five million hectares (12,350,000 acres). This area consists mainly of broad valleys flanked by low rolling ranges. Natural seepages are not known to exist, but there are secondary evidences of the presence of oil. The outcropping rocks are mainly Paleozoic (Silurian and Devonian sandstones and shales). Albertite and other forms of polymerized petroleum have been found in this region. Of these three main oil areas, only the first one is at present productive on a small commercial scale. This zone, developed almost exclusively by the Standard Oil Co. of Bolivia, a subsidiary of the Standard Oil Co. of New Jersey, is divided from south to north into the following local fields: 1. Bermejo (On the Argentine border) 3. Sanandita 5. Camatindi 2. San Telmo 4. Caigua 6. Machareti

Jan 1, 1935

By L. L. Newman

As soon as the Congress recognized the alarming rate at which our domestic oil resources were being depleted during the war, it took action to step up the rate of research and development which the Bureau of Mines had been conducting for several years on the production of synthetic liquid fuels from coals. Under Public Law 290, approved April 5, 1944, funds were authorized for the Bureau to proceed with research, development, design and construction of demonstration plants for the hydrogenation of coal, the synthesis of oil from carbon monoxide and hydrogen, and the distillation of oil from shale. During the latter part of 1944, when it became evident that the collapse of Germany was near, a Technical Oil Mission was organized to study the Ger- man techniques of synthetic oil production. Since the cost of hydrogen or synthesis gas is one of the major factors of expense in the operation of hydrogenation or synthesis gas processes, the Bureau of Mines considered it of prime importance to include on the mission gas engineers whose instructions were to examine closely the methods employed by the Germans in solving the problem of providing low- cost hydrogen or synthesis gas for their very extensive operations on synthetic liquid fuels. The Solid Fuels Mission and the Utilities Mission, as well as the Army and Navy Missions, also included teams for the study of German gas production. Although their objectives naturally differed from those of the Technical Oil Mission and from each other, it was recognized that there was considerable overlapping of their fields of investigation. Duplication of effort, however, was largely avoided through the close cooperation between the group leaders of these missions. For example, although I went to Europe as a member of the Technical Oil Mission, my first German assignment was actually made by Dr. Harry F. Yancey, leader of the Solid Fuels Mission- to investigate the brown-coal gasification methods in central Germany. The art of gasification in the United States and England, and to a large extent in the proximity of the coking-coal regions of Germany and the rest of continental Europe, depends essentially on two stages of operation; namely, carbonization and intermittent water-gas generation. As far as the United States is concerned, complete gasification in a single stage of operation is rarely practiced, except in gas-producer operations where the product is a relatively lean gas consumed close to the point of manufacture, and for water-gas production with anthracite as a generator fuel. Complete gasification of bituminous coal has been the subject of numerous investigations. Many relatively simple modifications of the water-gas generator have been tried to permit the direct gasification of low-cost bituminous coal instead of high- cost coke and anthracite for the production of water gas. Although varying degrees of success have been achieved and the water gas produced generally has been higher in calorific value, in only a few isolated in- stances has there been any sustained use of bituminous coal for water-gas production for public utility uses after the shortages of anthracite and coke have been lessened.

Jan 1, 1946

By John Birkinbine

Forty years ago, when the first shipments of iron-ore were made from the Lake Superior region, the supply for the blastfurnaces active at that date was in most cases a local consideration ; the majority of the smelting-plants being close to the oremines. Of those which depended in whole or in part upon ores brought from distances greater than an economical wagonhaul, few obtained supplies by canal or railroad from points 50 miles removed. At the present time the ore-supply is a local consideration for but a small proportion of American blast-furnaces, and 700 miles or more separate a greater num-

Jan 1, 1898

By G. Sachs

X-RAY analysis and single-crystal study have been utilized in recent years as a new means of following constitutional changes in alloys. If such transformations can be suppressed by rapid cooling, they can be followed at room temperature in a particularly convenient manner. In the following we shall consider changes in solubility and polymorphic transformations with particular reference to phenomena of the age-hardening type. Finally a thermodynamic viewpoint is developed for examining such transformations.

Jan 1, 1931

By J. W. Rutter, K. T. Aust

THE object of the experiments to be described in this report was to determine, first, which grains, out of a large number introduced into a sample in which their growth could proceed, were able to grow most successfully; and, second, the factors which control their growth selection. In an earlier study of grain boundary migration in high-purity lead,' it was found that, under some conditions, the most successful grain in an experiment of this type bears a special orientation relationship to the grain into which it is growing. The present work represents an extension of the previous study, directed at the determination of the orientation relationships which appear under a wider variety of conditions. Experiments of this general type have been done using commercial aluminum2 with somewhat conflicting results. In the present experiments, in contrast to the above,' the sample composition was a principal controlled variable, resulting in a considerable clarification of the phenomena observed. EXPERIMENTAL TECHNIQUE The experimental technique used in this investigation was essentially that employed previously in studies of grain boundary migration kinetics.1'3 The material used was zone-refined lead with various small amounts of tin or silver added to study the effect of varying the sample composition. The specimens were in the form of single crystals, about 1/4 in. 1/4 in cross section by 3 to 4 in. in length, grown from the melt in a horizontal graphite boat. A crystal grown in this way generally contained a lineage or "striation" substructure of the type shown in Fig. 1 of Ref. 1. This substructure consists of an array of low-angle boundaries which partition the crystal into regions misoriented from each other by a few degrees. The substructure constitutes a source of driving energy, estimated to be about 4000 ergs per cc, for the migration of a large-angle grain boundary into the striated crystal. New grains were introduced by plastic deformation in compression of a localized reglon at one end of the sample. Re-crystallization occurs at room temperature in the deformed region, introducing a large number of new, striation-free grains into the specimen. These grains are able to grow into the melt-grown crystal on annealing at a suitable temperature. The stria-tions are removed by passage of the grain boundary, as the substructure energy is utilized to produce the boundary migration. Usually, only one or two of the recrystallized grains persist after growth has occurred for about 1 cm out of the deformed region. Laue back-reflection X-ray photographs were obtained to determine the orientation relationship between the melt-grown crystal and the recrystallized grain or grains which grew most successfully in each specimen. EXPERIMENTAL OBSERVATIONS Fig. 1 shows the results obtained for a series of specimens to which had been added tin in the range from 0 to 5 ppm by weight. In this figure is plotted, in the standard stereographic triangle, the single axis about which the most successful recrystallized grain or grains are related to the starting, melt-grown crystal by the smallest rotation. The range of angular rotations observed about such axes is indicated beside each stereographic triangle. The results shown in the stereographic triangle on the left, Fig. l(a), were obtained by localized deformation at one end of each specimen at room temperature, followed by annealing in a furnace which had been preheated to 300°C. The furnace atmosphere was argon. It will be seen that the orientation relationships observed between the melt-grown and recrystallized grains are quite random. On the right, Fig. l(b), are shown results for samples in which the de-

Jan 1, 1961

By H. H. Kellogg

Equations representing the standard free energy of formation as a function of temperature, for thirty metallic chlorides, are presented and plotted on a free-energy vs. temperature diagram. The use of these data for calculations on reduction of metallic chlorides, refining of metals with chlorine, and chlorination of metallic oxides and sulphides is illustrated. CHLORINE metallurgy' has attracted metallur- gists for more than a century because the unusual properties of the metallic chlorides—low melting point, high volatility, and ease of formation from the oxides—make possible many useful extractive processes. Interest in chlorine processes is undergoing a renaissance due to present availability of chlorine at relatively low prices, and to recent advances in technology. During the present century there have accumulated a considerable number of reliable values of the thermodynamic constants for the metals and their chlorides. These data permit the calculation of free-energy equations for many metallurgically important reactions. Consideration of free-energy values makes possible certain predictions of the direction and extent of a given reaction, as well as the effect of temperature, pressure, and composition upon the result. Reaction rate, although not predictable from free-energy data, is usually sufficiently great at elevated temperatures that diffusion of the reactants and products to and from the zone of reaction determines the actual rate. Thus, if the free-energy indication is favorable, the chances are good that a high temperature metallurgical reaction will proceed at a reasonable rate, if adequate provision for rapid diffusion has been made. This paper presents standard free-energy equations for a number of metallic chlorides, based on data which are scattered throughout the literature. The equations are presented in a form that simplifies their use, and typical examples are given of the application of free-energy data to metallurgical processes. Free Energy of Reaction The free-energy change (AG) of a reaction is the true measure of the "driving force" of the reaction under a given set of conditions, and this is related to the standard free-energy change (AGO) of the reaction as follows: For the reaction: bB + cC = dD + eE ?G = ?G°+RTln ADd. AEA / ABb. ACc where A, = activity of constituent (i) T = absolute temperature, OK R = gas constant The criterion of a spontaneous reaction from left to right, at constant temperature and pressure, is a negative value for the free-energy change (?G). The standard free energy of the reaction is equal to the free energy of the reaction when all the reactants and products are at unit activity, since under these conditions the second term on the right-hand side of eq 1 is equal to zero. The concept of activity is treated fully in many textbooks on chemical thermodynamics1 and in a recent article by Chipman.2 Briefly, the activity (A,) of a constituent (i) is a measure of the reactivity of this constituent relative to its reactivity in some arbitrary standard state. For liquids and solids the standard state most often used is the pure liquid or solid constituent. Thus the activity of a pure liquid or solid in a metallurgical reaction is equal to unity. Gases under moderate pressure and at elevated temperatures behave very nearly as 'idea1 gases,' and the standard state is chosen as the gas at 1 atm pressure. The activity of an ideal gas is therefore equal to its partial pressure, and this relation is sufficiently exact for real gases in most metallurgical reactions. For a liquid or solid solution there is in general no simple way to express the activity of a constituent as a function of its concentration, and activity must be determined by experiment. A few solutions follow a so-called 'ideal' behavior, and if the pure constituent is chosen as the standard state, the activity of a constituent in an ideal solution becomes equal to its mol fraction. When a reaction reaches a state of thermodynamic equilibrium at constant temperature and pressure, AG becomes equal to zero and eq 1 reduces to: [ADd . AEe ?G°=RTln Abb ¦ Ac c equilibrium [2] The brackets surrounding the activity term are used to emphasize that each of the activities is an activity under equilibrium conditions—not just any arbitrarily assigned value. The bracketed term is the equilibrium constant (K) of the reaction. Eq 2 makes possible the calculation of equilibrium activities for a given reaction, if AGO is known at the desired temperature. The standard free-energy equations presented in this paper were calculated from the fundamental thermodynamic values of enthalpy of formation at 298°K (AH°,), standard entropy at 298°K (So298), heat capacity as a function of temperature (Cp), and enthalpies of transition, fusion, vaporization, and sublimation for the various constituents. Where possible the data reported in the recent "Selected Values of Chemical Thermodynamic Properties," published by the Bureau of Standards," were used. A large number of data came from the publications

Jan 1, 1951

Jan 1, 1928

By E. C. Wright

FOR many years the cost of making pig iron and steel in the Birmingham district has been about the lowest in the United States. The close proximity of the important raw materials such as coal, iron ore, limestone, and the large available scrap supply made it possible to assemble all of the important ingredients necessary for steel- making with only nominal costs for transportation. Both iron ore and coal were being mined in this district at one time for about $1 per ton from underground operations. At that time mining wages were low everywhere and the labor rate in the South was considerably below that of other mining districts. This situation persisted until the emergence of labor unions as an economic and political force, emigation of southern labor to northern plants, and continued growth of industry in the South in the years following the depression of 1932. Since that time union organizing of miners and steel workers throughout the nation has increased labor costs in mining and steelmaking. This influence has been felt particularly in underground mining operations since the proportion of labor cost to total cost is still high. The previous advantage in basic labor rate in the South has been almost entirely eliminated by the equalization of labor rates in basic industries by national unions. Since 1945 these influences have been especially noticeable in increasing the cost of mining coal and iron ore in the South. The northern steel districts are still being largely supplied with iron ore from the Minnesota open-pit mines and the cost of this ore has not increased nearly as much as the cost of ore obtained from underground mines in Birmingham. A similar situation exists in coal mining; the thinner seams in Alabama are not so amenable to mechanization as the northern mines and, as a result, the output per man-day in southern mines is only about three tons of coal as compared to five or six tons per man-day in the large captive mines of West Vir-

Jan 1, 1950

By Edwin Hopkins

THE year 1923 started a few days after the Venezuelan Oil Concessions, Ltd., discovered a 140,000-bbl. well at. La Rosa and a well of between 2500 and 5000 bbl. at La Paz, on the opposite side of Lake Maracaibo. These nearly simultaneous events changed, overnight, the general aspect of oil affairs in Venezuela. Up to that time, big things had been expected by the companies then in the district, but many major companies had shown little interest in the country. Within a few weeks the Pure Oil. Co. and the Gulf Oil Corpn. entered the field and acquired large properties. The Texas Co. purchased several concessions and the Standard of California, Atlantic Refining Co., and Mexican Petroleum Co. established offices. Representatives of many other companies visited the district during the first few months of the year. The sudden influx of buyers naturally caused a great rise in prices and this, together with overproduction in the United States, doubtless caused the slowing up of concession transfers in the latter part of the year. The following property transfers occurred: (1) The Gulf Oil Corpn. contract with the Maracaibo Oil Exploration Corpn., whereby the Gulf acquired the right to select 100,000 acres from the Maracaibo's zones. (2) The Gulf Co. purchase of one-quarter interest in seven concessions of the New England Oil Corpn., Ltd. (3) The Gulf Oil Corpn. purchase of several concessions of Kunhardt and others in the Perija district. (4) The Gulf Oil Corpn. purchase of certain portions of the one-kilometer Lake zone that were not covered by parcels or Government reserves (namely the "sobrantes"). (5) Pure Oil Co. purchase of all Government reserves turned back by Maracaibo Oil Exploration Corpn. in the districts of Mara and Miranda. (6) Standard Oil Co.: of New Jersey deal with the British Controlled Oilfields, Ltd., for control of approxi-mately the eastern third of the .district of Buchivacoa, state of Falcon. (7) Royal Dutch deal with the British Controlled Oilfields, Ltd., for the control of the central third of the district of Buchivacoa, Falcon. (8) The Texas Co. purchase of several concessions in Perija and one west of Mene Grande on the east side of Lake Maracaibo. (9) Purchase by the British Equatorial Oil Co., Ltd., of Goverment reserves corresponding to certain Creole Syndicate parcels under the margin of Lake Maracaibo near La Paz. (10) The Lago Petroleum Co. acquired a concession on all of Lake Maracaibo except a 1-Km. strip along the shore.

Jan 3, 1924

By Lloyd Pollish, Robert N. Breckenridge

SUCCESS in any underground mining operation is determined by accessibility of the orebody, which in turn is dependent upon maintenance of passageways to the mining zones and temporary support of the voids caused by extraction of ore. This is accomplished by one or a combination of the following methods: timbering, back-filling, pillaring, or, more recently, rock bolting. Timbering has usually been the principal means of maintaining these underground openings necessary for mining operations. Timber, however, does not prevent ground movement beyond the scope of localized sloughing, which is indicated by the gradual failing of the timber itself. Besides this, timbering has always been a costly process, and with the decline of available supplies of timber close to the mining areas, mining men have constantly sought other methods of controlling ground. Rock bolting is now replacing timbering at an ever increasing rate. Experience has proved that this form of ground support is just as applicable to blocky igneous rock as to stratified rock. Besides preventing sloughing of the walls and back of underground openings, Fig. 1, rock bolting has a stabilizing effect on the surrounding ground in much the same manner that steel reinforcing rods add to the strength of concrete structures. Further, rock bolting is flexible and may be applied to any shaped excavation, whereas timber sets are in a fixed pattern and the ground must often be changed to conform with this pattern. Rock-bolting installations were made in metal mines of the Northwest as early as 1939. An exhaust air crosscut was driven that year in one of the Butte mines of the Anaconda Copper Mining Co. The crosscut was rock-bolted and gunited at the time it was driven and is still being used to exhaust hot humid air from the 3400 level of the Belmont mine. It is interesting to note that no sloughing or caving has taken place in the 14 years it has been open. Even though these early installations of rock bolts were successful, few men recognized their potentiality until recent years, when the coal mines started their programs of mechanization and the great trend toward roof bolting began. In some areas of the Northwest stopes that previously required heavy timbering and close backfilling are now being mined by the more economical cut-and-fill and shrinkage methods. When used in conjunction with timbering, rock bolting increases the efficiency of the operation by decreasing hanging wall dilution and by making it possible to blast larger rounds. Most of the rock bolts installed to date in mines of the Northwest have been the 1-in. diam slot and wedge type, but there has been a recent trend to- ward using the 3/4-in. diam expansion shell bolt shown in Fig. 2. In addition to these commercially manufactured steel bolts, wooden bolts have been used with considerable success by the Day Mines of Wall'ace, Idaho. Installation of the slot and wedge type requires three distinct operations, with tools for each operation: 1—drilling the hole to proper diameter and depth, 2—setting the bolt, and 3—tightening the nut. Holes are drilled and bolts set with pneumatic rock drills. A number of setting or driving tools have been used successfully, but most follow the same general pattern. Usually the driving tool is designed to accommodate a short length of drill steel on one end and the rock bolt on the other end. In this manner the hammering effect of the rock drill is transmitted through the steel and driving tool to the bolt. When machines not having stop rotation are used, slippage is allowed between the driving tool and bolt or between the drill steel and driving tool. The rock bolt nuts are tightened either with pneumatic impact wrenches or with hand wrenches. Impact wrenches are desirable because they are faster and assure adequate tightness. Expansion shell bolts have the following advantages over slot and wedge rock bolts: 1—No special equipment other than a wrench is needed for their installation. 2—Installation is faster. 3—They are removable. 4—Holes need not be drilled to a specific depth as the expansion shell will anchor anywhere along the length of the hole. These advantages are offset somewhat by the lesser strength of the bolt, since expansion shell bolts are generally made from 3/4-in. diam steel as compared to 1-in. diam steel for the slot and wedge type. One manufacturer, however, is now fabricating expansion shell rock bolts from steel of high tensile strength, which gives this ¾-in. bolt a much greater strength than that of the mild steel bolt. Table I illustrates tests made by the Anaconda Copper Mining Co. to determine the proper hole size to use with various types of bolts and to determine

Jan 1, 1955

By A. H. Jones

(San Francisco Meeting, September, 1915). THE Belmont mill at Tonopah, Nev., was designed and constructed by the Belmont staff. Ground was broken in August, 1911, and milling operation started July 25, 1912. The metallurgical flow sheet, and the machinery adapted to carrying out operations in accordance with this plan, were decided upon from experience gained in the treatment of Belmont mine ores at the old Belmont mill at Millers, Nev. The detail drawings were made by the-engineering staff of the Tonopah-Belmont Development Co., under the supervision of Otto Wartenweiler, who also .had direct charge of the construction, consulting with the General Superintendent of the company, Frederick Bradshaw, and the writer.

Jan 8, 1915

Jan 1, 1929

By Steven Mitchell

BACKGROUND Homestake Mining Company began milling operations at the Bulldog Mountain Mine near Creede, Colorado in 1969. The Bulldog Mill, rated at 350 tpd, produces a bulk flotation condentrate assaying about 180 oz/T Ag and 20% Pb, from heads of about 16 oz/T Ag and 2% Pb. The circuit is straightforward with two-stage grinding to 1-5% plus 65 mesh, followed by rougher and cleaner flotation. Reagents used are Z-6, Z-11, Aerofloat 242 and Aero Promoter 404, with an Aerofroth 65-MIBC mixture for a frother. Additional information on the geology, mine and mill are available in references (1) and (2). A flow sheet for the mill and CIP plant together is attached as Figure 1. Final flotation tailings normally vary from 1.5 - 2.0 oz/T Ag. These tailings are cycloned to produce sand for underground backfill. After cycloning, the sands are repulped and given a final scavenger float. This sand scavenger recovers a small additional amount of silver which recycles back to the main flotation circuit. The tailings are recycloned and pumped to the mine or, if the mine cannot accept sand, to tailings. The majority of the silver in the flotation tailings exists in the fine fractions; cycloning upgrades the slimes and lowers the assay of the sand. The sand, after scavenging, typically assays 0.5 oz/T Ag, and the slimes assay about 3.0-3.5 oz/T Ag. From 1969 to 1976 all of the slime tailings and the sand tailings not used underground were impounded in a tailings pond located about

Jan 1, 1983

By Thomas S. Blair

I FEEL a certain sense of responsibility in bringing before you the subject of the direct process in iron manufacture. I am aware that, in such a body as I have now the honor of addressing, there are few who are not already so well informed upon its past history that it would be a weariness to them to listen to anything else than an account of practical success. Yet, to claim that success involves so much that, if I do not make good my claim, I deservedly expose myself to severe criticism. The whole literature of the art, so far as it relates to the direct process, is, up to this time, but a history of failure. It is safe to say that more money, time, and talent have been fruitlessly spent in the pursuit of this object than in all the other unsuccessful efforts in the whole line of iron metallurgy. A distinguished authority in patent law has remarked that " the invention records of the United States and of foreign countries are filled with the waifs and abandoned relics of these abortive struggles." Dr. Percy, whose great work may be taken as an epitome of all that was worth mention, whether useful or curious, in pig-iron metallurgy, up to the date of its publication (1864), after giving elaborate accounts of various attempts at the direct process, condenses his own opinion of all that had been then effected, into a brief but summary comment upon a pamphlet of one of the sanguine inventors who had said: "It is evident that the present mode of working iron

Jan 1, 1874

By D. H. Newland

On the bulk basis New York's contribution to the production of oil is small, representing, as it does, a bare half of one per cent of the annual total for the United States. Yet it has more importance than is implied by such a statement. Petroleum includes a variety of organic compounds, some more and some less valuable. It would be a fairer estimate of the situation to say that New York in recent years has produced around 10 to 12 per cent on the average of all Pennsylvania grade oil, the supply of which is strictly limited and the demand steady even in times of overproduction of other grades. One may not infer from this that New York and other Appalachian states enjoy an independent position in the market with a price structure uninfluenced by that of the Mid-Continent, Gulf or California fields. On the other hand, the recent market demoralization in the South and West brought about by uncontrolled production caused prices to drop to a point where the life of the local industry was seriously threatened. The current cost of producing oil in New York under the methods of water-flooding, by which most of the output is now obtained, has been estimated by competent authority at not less than $2.50 a barrel. The

Jan 1, 1934

By D. B. Williams

The end of the war in Europe and the Pacific failed to curb the upward trend of production in Venezuela,- which easily surpassed that of any previous year. The total production for 1945 amounted- to 323,369, 430 bbl., which was 26 per cent over the total for 1944, the previous peak in the history of the oil industry of the country. This increase was caused mainly by the greater demand for petroleum in the last stages of the war; the fact that the danger from enemy submarines had been overcome, which allowed all oil companies to use increased shipping facilities, and the fact that more materials were available for drilling operations. However, the materials supplied were by no means adequate and considerable credit is reflected on the Venezuelan petroleum industry for the increased production obtained by utilizing all available equipment to its fullest extent.

Jan 1, 1946

By James E. Adler, Timothy C. Richmond

The Stillwater District is located in south central Montana approximately 75 miles southwest of Billings, the state's largest city. It lies along the northeast front of the Beartooth Mountains and is within the boundaries of the Custer and Galatin National Forests. The first white visitors in the district were the early trappers, who were soon followed by the prospectors. These early prospectors were drawn to the area by gold and silver discoveries at Cooke City in 1870 as well as by the large gossan formation in Verdigris Creek near the west bank of the Stillwater River and by several scattered smaller gossan exposures throughout the area. The first patented mining claims were recorded in September, 1886.

Jan 3, 1974

By E. P. Klier, Taylor Lyman

THE structures formed when austenite is quenched to subcritical temperatures and allowed to transform isothermally have been the subject of intensive study since the work of Davenport and Bain.1 Isothermal transformation diagrams summarizing the results of many of these studies have become widely familiar to metallurgists. Of particular interest to metallographers are the dark-etching, acicular products of transformation formed by isothermal reaction below the temperature of maximum velocity of the austenite to pearlite reaction. These products, the bainite structures, can be formed in a wide variety of steels. However, the constitution of bainite is not well understood and divergent views have been expressed as to its mode of formation. In this investigation a combination of dilatometric, microscopic and X-ray methods has been brought to bear upon the problem in the hope of some elucidation of the bainite reaction as it occurs in hypoeutectoid steels. MECHANISM OF BAINITE FORMATION Davenport and Bain1 considered the mechanism of bainite formation to consist of two steps-an allotropic transformation followed by precipitation of carbide. The separation in time of the two processes was considered to be very slight in the upper temperature range and very marked at temperatures just above the martensite range. This concept has been restated by Vilella, Guellich and Bain2 in the form of a definition of the acicular mode of transformation as: The successive, abrupt formation of flat plates of supersaturated ferrite along certain crystallographic planes of the austenite grains; this supersaturated ferrite begins at once to reject carbide particles, (not lamellae), at a rate depending upon temperature. In effect, this is the acicular mode of transformation, even though the temperature be such as to limit the actual life of the quasi-martensite to millionths of a second. The investigation of isothermal decomposition of austenite in certain alloy steels (notably those containing chromium or molybdenum) has revealed that there may be a range of temperatures between the pearlite and bainite reactions in which the austenite decomposes at a relatively low rate.3-6 Further, it is characteristic that in the second region of fast reaction the decomposition of the austenite is incomplete by one reaction but goes to completion by a second reaction. These observations led Wever7 to a description of the bainite reaction as follows: I. The reaction takes place by initial precipitation of a martensitic intermediate structure. 2. In the upper temperature range this structure readily decomposes into ferrite and cementite. In the lower range carbon separates in an unknown form. 3. In the upper temperature range the precipitated carbide nucleates the precipitation

Jan 1, 1944

By James Bowron

CONSIDERING the importance of the steel trade and the strategic position occupied in it by the Birmingham District, it may be surprising to many to realize that even the first pig iron smelted with coke was made in Alabama on Feb. 28, 1876, although merchant pig iron had been produced in Rockwood, Tenn., in 1867, a plant which is still in active operation. The heavy deposit of Clinton ore extending from Pennsylvania into Alabama, varying greatly in accessibility on account of geological changes such as erosion or anticlinal upthrow, varies equally as much in thickness and in quality. The brown ores extensively scattered through the South also vary materially in quality, some being relatively low in phosphorus and high in manganese, and vice versa. The red ore varies materially in phosphorus, but the iron produced from these ores was always considered to be too high in phosphorus for treatment by acid Bessemer or open hearth and did not contain sufficient for the basic Bessemer process. Under these conditions there remained only the basic open hearth as a possibility, and for many years it appeared impossible to use it, because, with coke smelted iron, the silicon was too high to permit its use in basic lined furnaces.

Jan 1, 1924