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By N. H. Muhlenberg

IT is often a tedious matter to get a solution of pig iron or steel, for the determination of phosphorus, which is absolutely free from silica. Where pig iron rich in silicon is dissolved in hydrochloric or nitric acid in the usual procedure, it is necessary, not only to evaporate the solution to complete dryness, but to heat the dry residue for some hours in an air-bath to a temperature of about 120° C. The oxide of iron is thus rendered insoluble in nitric acid, and is only slowly dissolved by hydrochloric acid. In the method of determining silicon by nitric and sulphuric acid, described in the Transactions of the Institute, Vol. VII, page 346, and Vol. VIII, page 508, we obtain in one or two hours a solution of the iron in the form of ferric sulphate entirely free from silica, and containing free sulphuric acid. It occurred to us that this solution might be made available for the determination of the phosphorus by the molybdate method. The following experiments were tried with unsatisfactory results. 1st. The iron was precipitated by ammonia, the precipitate filtered, washed, and dissolved in nitric acid. 2d. The iron was precipitated as basic acetate and dissolved in nitric acid. 3d. The solution was neutralized by ammonia, and nitric acid added in small excess. In all these cases the phosphorus obtained by precipitating by ammonium molybdate and magnesia-mixture was too low. The following method was then tried with success. The filtrate from the silica and graphite was evaporated to small bulk and heated in a porcelain dish on a sand-bath, until fumes of sulphuric acid ceased to escape. The dry residue was taken up with dilute nitric acid and the solution precipitated by ammonium molyhdate. The phosphorus was weighed as magnesium pyrophosphate. The results were satisfactory. To save time, the original solution of the iron in nitric and sulphuric acids was evaporated to dryness and heated as before until

Jan 1, 1882

By LeRoy Scharon

EACH year it becomes apparent that geophysical activities in the fields of mining and engineering are increasing in the number and variety of applications. Many mining companies are including, as part of their exploration programs, geophysical surveys. The value of geophysics in highway and structural foundation investigations has been realized and is now an important part of subsurface investigations in conjunction with soil and rock borings. United States of America One of the major orebody discoveries of the year is that of the Grace mine near Morgantown in Berks County, Pa. This orebody, now under development by the Bethlehem Steel Co., was discovered by an airborne magnetometer survey carried out by the Aero Service Corp. of Philadelphia. The orebody, the geological occurrence of which is similar to those existing at Cornwall, Pa., was found at a depth of 1500 ft under a cover of Triassic sediments and is reported to have a reserve of well over 100 million tons. Shaft sinking and other construction work has started at the site. Resistivity work was carried out at proposed dam sites in New York and in connection with the search for fluorspar veins in Kentucky. Spontaneous polarization investigations were pursued in the Appalachian region at various localities from North Caro¬lina up into Virginia. This work was done in connection with the search for sulphide-bearing structures. Several indications were proven by subsequent drilling to correspond to unknown sulphide deposits, a few of these occurring in the vicinity of properties long under exploitation. Refraction seismic methods applied to bedrock depth determinations as related to water problems on the Marquette Range and the extension of the. regional gravity survey on the Menominee Range to learn the major structural features of the area have been reported by, Lloyal O. Bacon. A gravity survey has been completed in the vicinity of Tioga, Bradford County, Pa. with a gravity profile being observed from Tioga east to the Delaware basin. The Indiana Geological Survey is concerned with a state-wide gravity survey. Judson Mead, University of Indiana, reports that the bulk of the State Survey's geophysical work, however, has been "seismic refraction work in connection with drift thickness problems. The survey has made almost 1000 determinations in areas of moderately thick drift. The results of this work are of interest to both the coal mining industry and to the stone industry." In the southeastern Missouri lead belt, magnetic electrical resistivity, and electromagnetic applications for the discovery of new lead deposits have been used with success. A gravity survey of the residual-barite deposits in Washington County, Mo., was made during the summer season with preliminary computations of tonnages checking with tonnages mined. Robert M. Dryer, of the University of Kansas has had considerable success in mapping structural features in southwestern Kansas with the gravity meter and is now engaged in tracing shoestring sands in eastern Kansas by resistivity surveys. Several, foundation sites were investigated in greater St. Louis using electrical resistivity and seismic refraction methods with success. A minimum amount of drilling data was available for checking and interpreting the geophysical results (Fig. 1). It is to be noted that geophysical methods are finding a place in subsurface investigations for highway and foundation problems. Interest has been so keen in this field that the American Society for Testing Materials, at its annual meeting in June of this year, devoted one session of its symposium on surface and subsurface reconnaissance to geophysical papers involving the application of the electrical resistivity and seismic refraction methods to subsurface studies. At least three major mining companies in the United States have entered the field recently in geochemistry. The program of research and development of geochemical techniques by the U. S. Geological Survey continues. Experimental field projects were conducted over lead-silver, cobalt, copper and zinc deposits in Idaho, Oregon, California, Wisconsin and Montana. Similar experiments were carried on by M. P. Nackowski in the Illinois-Kentucky fluorspar district and in the Tri-State Zinc district by R. Maurice Tripp with favorable results. Geophysical activities of the U. S. Geological Survey for 1951 were extensive and varied. About 21,000 miles of airborne magnetic and 10,000 miles of airborne radioactivity traverse were flown in 1951 by the U. S. Geological Survey. A total of 35,000 miles of aeromagnetic traverse were compiled, 57 aeromagnetic maps were published and 14 preliminary maps were placed on open file. Airborne surveys were made in Aroostook County, in the Katahdin and Dead River areas in Maine; in northwest Washington; over the Mother Lode district in California; in northeastern and northwestern Minnesota; and in the New York-New Jersey highlands. Of special interest were the surveys in Washington, where highly magnetic Eocene lavas gave information on structures in the overlying Miocene sedimentary rocks and in northeastern Minnesota over the Duluth gabbro. The latter survey was made following the discovery of nickel-copper mineralization in the gabbro near its contact with the Virginia slate. The principal ground geophysical surveys for metalliferous deposits and related purposes were made in the Colorado Plateau region, where electrical surveys assisted in prospecting; in Aroostook County, Maine, where ground magnetic surveys, following aeromagnetic surveys, have permitted tracing

Jan 1, 1952

By M. D. Hassiaslis

THE nature of a collector-coated mineral surface has been the subject of some experimentation and much speculation. Various aspects of the problem have been isolated and studied; it is probable, however, that there exist aspects as yet unrecognized, which are needed for a complete description of the system. The recognized elements of the problem are: 1-The nature of the chemical units comprising the film and the nature of the forces holding these chemical units to the mineral surface; 2-The orientation of the chemical units at the surface; and 3-The disposition of the collector units at the mineral surface. This report touches upon all three aspects of the broad problem; it deals, however, with a new and heretofore unrecognized element-the mobility of the collector units in the two dimensions of the solid-liquid interface.

Jan 11, 1951

By G. Thodos, E. M. Phillips

A reduced density correlation for the gaseous and liquid regions of ethane has been developed from all the experimental PVT data available in the literature for this substance. Saturated vapor and liquid densities reported for methane, propane and n-butane were utilized to establish the rectilinear-diameter line for ethane. This line was then used with the saturated-vapor data for ethane to produce the saturated envelope for this substance. Most of the saturated liquid data reported for ethane were found to be inconsistent with the saturated-liquid curve resulting from this study. The correlation covers the regions 0.65 < TR <6.0 and 0 < PR < 15. For regions for which no experimental data have been reported, the isobars of the correlation were extended by the use of the theorem of corresponding states. This correlation is presented both on rectilinear and log-log coordinates. INTRODUCTION At the present time, there is considerable interest in the exact PVT behavior of pure hydrocarbons. Matschke and Thodos12 recently have developed a comprehensive compilation of experimental vapor and liquid density data for methane. Similar studies have been conducted for other pure substances.4, 7 In the present study the density data available in the literature for gaseous and liquid ethane have been critically reviewed and utilized to develop a reduced density correlation for this substance. SATURATED LIQUID AND VAPOR DENSITIES The rectilinear-diameter rule proposed by Cailletet and Mathias5 states that the sum of the saturated liquid and vapor densities of a pure substance is a linear function of temperature which passes through the critical point. This law, although empirical, has been well established by continued verification since its conception in 1886. This rule has been applied to the saturated density data of methane,6 propane 17 and n-butane8 to produce the straight lines presented in Fig. 1 which pass through the critical point TR = 1.00, Pr = 2.00. The rectilinear-diameter relationship for ethane was established from the lines for the other substances in Fig. 1 by plotting the quantity p~, + PR against zc for different reduced temperatures. A critical analysis of the saturated vapor and liquid densities reported for ethane by Kuenen,10 Maass and McIntosh,11 and Sage, Webster and Lacey18 revealed that the values of PR1 + pr resulting from these studies were inconsistent with the rectilinear-diameter line obtained from the reliable density data of the other substances, as shown in Fig. 1. In the analysis of these data, reduced quantities were calculated using the critical con-

By Robert M. Betts

The Cornucopia district is situated in northeastern Oregon 25 miles from the Snake River branch of the Oregon Short Line R.R. and 75 miles northeast of Baker City, in the Wallowa Mountains. The formation is principally granodiorite, which has intruded much older rocks locally known as greenstone, and which are probably altered schists. In the upper horizons of the veins, greenstone is found as inclusions in the granitic mass. Both of these formations have been cut by numerous basalt, aplite, and porphyry dikes. Veins of the district are the result of faulting and the consequent crushing of the wall rock. The ore has been deposited irregularly along these faults and formed a lenticular type of vein. The ore varies in width from a few inches to 20 ft.; the average stoping width is about 5 ft. As the basaltic dikes are subsequent to the ore deposition, they are at times a hindrance in development and mining operations; on the other hand, a dike which has followed a vein as a line of least resistance often serves as a good mall in place of the crushed, rather loose granite. The veins generally strike northeast-southwest and dip about 35" to the west. Orebodies are from 100 to 300 ft. in length and about the same in height. The lenses are irregular; inclusions of wall rock are common in the ore and are a factor in reducing the grade. The ores are quartz, carrying some free gold near the surface, but the metals for the most part are in iron sulfides, sometimes associated with chalcopyrite. The gold and silver are in a mechanical combination with the iron, which requires find grinding to liberate them. The ratio of silver to gold is 5 to 1, by weight. Development The Cornucopia Mines Co. owns, and operated until 1920, two mines and two mills of 100 tons capacity each. The sustained high costs and labor shortage, however, necessitated the abandoning of the Union mine, the oldest in the district. Two crosscut tunnels were then started, first, to cut the Last Chance vein at a much lower horizon and, second, to prospect two parallel veins. The ore from the Last Chance vein will go to the old Union mill and the ore from the new veins to the Last Chance mill.

Jan 1, 1925

By N. H. Murlenberg, T. M. Drown

It is often a tedious matter to get a solution of pig iron or steel, for the determination of phosphorus, which is absolutely free from silica. Where pig iron rich in silicon is dissolved in hydrochloric or nitric acid in the usual procedure, it is necessary, not only to evaporate the solution to complete dry ness, but to heat the dry residue for some beam in an air-bath to a temperature of about 120° C. The oxide of iron is thus rendered insoluble in nitric acid, and is only slowly dissolved by hydrochloric acid. In the method of determining silicon by nitric and sulphuric acid, described in the Transactions of the Institute, Vol. VII, page 346, arid Vol. VIII, page 508, we obtain in one or two hours a solution of the iron in the form of ferric sulphate entirely free from silica, and containing free sulphuric acid. It occurred to Us that this solution might be made available for the determination of the phosphorus by the molybdate method. The following experiments mere tried with unsatisfactory results. 1st. The iron was precipitated by ammonia, the precipitate filtered, washed, and dissolved in nitric acid. 2d. The iron was precipitated as basic acetate and dissolved in nitric acid. 3d. The solution was neutralized by ammonia, and nitric acid added in small excess. In all these cases the phosphorus obtained by precipitating by ammonium molybdate and magnesia-mixture was too low. The following method was then tried with success. The filtrate from the silica and graphite was evaporated to small bulk and heated in a porcelain dish on a sand-bath. until fumes of sulphuric acid ceased to escape. The dry residue was taken up with dilute nitric acid and the solution precipitated by ammonium molyldate. The phosphorus was weighed as magnesium pyrophosphate. The results were satisfactory. To save time, the original solution of the iron in nitric and sulphuric acids was evaporated to dryness and heated as before until

Jan 1, 1882

By Kehsin Kuo

DIE steel with 1.47 pct C, 0.42 pct Mn, and 8.22 pct W contains Fe,C and WC in the annealed state and WC embedded in a martensitic matrix in the hardened state (quenched from 800°C). The presence of a large amount of undissolved angular WC carbide particles makes this steel extremely wear-resistant. However, the WC carbide begins to dissolve in the austenite when the heating temperature is raised above 1000°C, but this solution process is still not complete at 1250°C although partial melting has already taken place at the austenite grain boundaries. At 1325 C, this steel contains austenite and liquid metal but no WC carbide, Fig. 1. On quenching into brine, the liquid metal solidifies into a constituent which etches differently from the austenite-martensite matrix. This constituent appears lighter than the matrix at the 1250°C stage when etched with 2 pct nital but darker in Fig. 1 when etched with Murakami&apos;s reagent. Such a constituent has also been found in burnt tungsten high speed steels. This constituent has been isolated from the matrix by anodic dissolution in a 5 pct HC1 electrolyte and was found by the X-ray powder method to be iso-morphous with &manganese, Table I. The agreement in line intensity between these two phases indicates that there is no ordering in this new phase. The calculated cube edge of this phase is 6.395A, somewhat larger than that of ß-manganese (6.30A). Besides this phase, the anodic residue also contains free carbon from the matrix and amorphous WO,, although the X-ray powder pattern of the residue shows the presence of only this phase. This makes it impossible to determine directly the composition of this phase from the residue. Attempts to prepare an alloy containing only this phase have hitherto been fruitless. The following experiments serve to show that this phase can only be obtained by drastic quenching from the liquid state and that its tungsten and carbon contents must be lower than those in the Fe,W,C carbide. On air cooling from 1325oC, the liquid metal solidifies into a eutectic consisting of austenite and the Fe3W3C carbide. The nature of this dark-etching Fe3W3C has also been ascertained by X-rays. This eutectic becomes coarser on furnace cooling. The solidification of a specimen cooled for 5 min from 1325" to 1200°C and water quenched is still not complete and the fine eutectic is formed during the quenching. Since this new phase can be replaced by a eutectic of austenite and the Fe,W,C carbide, its composition must lie somewhere between the latter two phases. The special features of this phase are: 1—it can only form directly from the liquid state by drastic quenching and 2—it is a ternary phase of iron, tungsten, and carbon. The ß-manganese structure of this phase is also interesting. In the Periodic Table, iron and tungsten lie on opposite sides of manganese; a certain combination of these two elements, in the presence of carbon, may have average properties similar to those of manganese. It has already been established that the x phase, a ternary one of iron, chromium, and molybdenum, has the a-manganese structure."&apos; A similar phase has also been found in the ternary system Fe-Cr-W and in the following binary systems: Re-Cb, Re-Ta, Re-Mo, and Re-W.6 References 1 G. D. Preston: Philosovhical Magazine 11928) 5. 7th Series, p. 1207. - K. W. Andres: Nature (1949) 164, p. 1015. 35. G. McMullin, S. F. Reiter, and D. G. Eberling: Trans. ASM 11954) 46, p. 799. &apos; J. S. Kasuer: Acta Metallurgica (19541 2, p. 456. • H. J. Goldschmidt: Trans. ASM (19541 46, p. 807. P. Greenfield and P. A. Beck: Private communication.

Jan 1, 1957

By B. A. Rogers, K. O. Stamm

BECAUSE it is the basis of the economically important operation of hardening steel by quenching, the A3 transformation in iron has been the subject of numerous investigations. Although the contributions to this subject are interesting, no general review will be given here. Readers who care to follow the matter further are referred to the comprehensive summary by Cleaves and Thompson,1 which covers the literature to about 1935. Their references to 53 papers on the subject suggest that further investigation is hardly justifiable. However, considerable interest has developed recently concerning the reversibility of the transformation. From thermodynamic considerations, the transition ought to occur at the same point on heating or cooling, if the change of temperature is sufficiently slow. Yet all of the earlier investigators found a difference of several degrees. Burgess and Crowe,2 who used thermal methods, obtained average temperatures of 912° for Ac3 and 900°C. for Ar3 on electrolytic iron. Their data indicate a considerable range of temperature over which the change occurs, both on heating and on cooling. Terry3 measured the susceptibility in the critical range and estimated from the steepest parts of his curves that Ac3 came at 9180 and Ar3 at 903°C. Ishiwara4 was one of the first investigators to report a shorter interval between the temperature of the change in the two directions. He measured the change of susceptibility of kaolin-coated samples of steel, in a hydrogen atmosphere, at rates of heating and cooling so low that about 3 or 4 hr. were required for the transformation to complete itself. His results show some variability between samples, but indicate that the difference between Ac3 and Ar3 is in the vicinity of 6°C. Roberts and Davey5 measured the space lattice in pure iron in the vicinity of 900°°C. and concluded that a change occurs reversibly between 907° ± 3° and 9100 ± 3°C., probably between 907° and 910°C. Wells, Ackley, and Mehl6 made dilatometric determinations of the Ac3 and Ar3 points in samples of hydrogen-treated carbonyl iron maintained under a vacuum. They used three rates of heating and cooling: 2°, &apos;1/2°, and 1/8°C. per min. and found the spread between the two points decreased with low rates. At the slowest rate, the Ac3 transition occurred at 909° to 909.5°C. and the Ar3 change at 907°C. in three of the samples believed to contain the lowest percentages of alien elements. They concluded that if the rate of temperature change and the content of alien elements were low enough, the A3 transformation would be completely reversible at 909.5° ± I°C. The question of reversibility is an interesting one and when some iron with especially small percentages of alien elements became available the opportunity to conduct an investigation was welcomed. This iron was prepared by the Division of

Jan 1, 1941

Raymond Weir Smyth, born Nov. 3, 1888, was the son of Herbert Weir Smyth, professor of Greek Literature at Harvard University. He graduated (A. B.) from Harvard in 1909 and later pursued advanced studies there in chemistry and in metallurgy. He held the position of metallurgist for the American Steel and Wire Co. at Worcester, Mass., and also for the Steel and Tube Co. at Youngstomn, Ohio. For a time he was inspector of munitions for the British Government and stationed at the Railway Steel and Spring Co. at Latrobe, Pa. For a short time, in 1917, he was Inspector of Ordnance for the U. S. Government, and the following year, having entered the U. S. Naval Reserve Force, he was ordered in a similar capacity to the Midvale Steel Co. In September, he removed to the Navy Yard, League Island, Philadelphia, to train for the obligatory minimum of six months&apos; sea duty. There he contracted influenza, which was followed by pneumonia, from which he died, September 27, at the Navy Yard Hospital. Captain Braxton Bigelow* Captain Braxton Bigelow was the son of Major John B. Bigelow, U. S. A., retired, and grandson of the late John Bigelow, author, and Minister to France under President Grant. Captain Bigelow graduated

Jan 1, 1920

By Robert W. Hendricks, John B. Newkirk

A simple method is described for determining the orientation of a single crystal by means of a cylindr cal X-ray camera. Orientation setting to within ±1 deg is attainable by a stereographic analysis of a single cylindrical Laue pattern produced by the originally randomly mounted crystal. Final precision adjustments which permit orientation of the crystal to within ±5 min of arc from the desired position can be made by the method of Weisz and Cole. A chart, originally Presented by Schiebold and schneider7 and which allows a direct reading of the two stereographic polar coordinates of the corresponding pole of a given Laue spot, has been recomputed to aid in the stereographic interpretation of the cylindrical Laue X-ray photograph. Detailed instructions for the use of the chart, a simple example, and a comparison with the conventional flat-film Laue Methods, are presented. 1 HE problem of determining the orientation of the unit cell of a single crystal relative to a set of fixed external reference coordinates is fundamental to most problems of X-ray crystallography and to many experimental studies of the structure-sensitive physical properties of crystalline materials. Several techniques for measuring these orientation relations have been developed which correlate optically observable, orientation-dependent physical properties to the unit cell. Examples of such procedures include the observation of cleavage faces or birefringence, as discussed by bunn,1 or the examination of preferentially formed etch-pits, as discussed by barrett.2 Each of these methods is limited, for various reasons, to an orientation accuracy of approximately ±1 deg—a serious limitation in some experimental studies. Several other limitations decrease the generality of these methods. Of these, perhaps most notable is the absence in many crystals of the physical property necessary for the orientation technique. The most widely used methods for determining crystal orientation are variations of the Laue X-ray diffraction method. Because of the indeterminacy of the X-ray wavelength diffracted to a given spot, the interpretation of Laue photographs is now limited almost exclusively to the procedure of using a chart to determine the angular coordinates of the corresponding pole for each spot. For the flat-film geometries, either a leonhardt3 or a Dunn-Martin4 chart is used in interpreting transmission patterns, whereas a greninger5 chart is used for interpreting back-reflection patterns. A less common method of interpreting flat-film transmission Laue photographs is by comparing the Laue pattern with the Majima and Togino standards,6 or with the revised standards prepared by Dunn and Martin.4 Although this last method is applicable only to crystals with cubic symmetry, it can be very rapid and just as accurate as the graphical methods. The primary limitation of all the X-ray methods mentioned is the relatively small number of Laue spots and zones which are recorded on the flat film. Often, few, if any, major poles appear, thus making interpretation tedious and sometimes uncertain. The use of a cylindrical film eliminates this problem. Schiebold and schneider7 prepared a chart by which the orientation of the specimen crystal could be determined from a cylindrical Laue photograph. However, it was only drawn in 5-deg intervals of each of the two angular variables used to identify the Laue spots, thus limiting the accuracy of orientation to about ±3 deg. An examination of this chart indicated that if it were drawn in 2-deg intervals, crystal orientations to ±1 deg would be attainable. Subsequent use of the replotted chart has confirmed this accuracy. It is the purpose of this paper to describe the redevelopment and use of this chart, and to point out its advantages and limitations. I) CAMERA GEOMETRY AND CHART CALCULATIONS The geometry of the cylindrical camera with a related reference sphere is shown in Fig. 1. The X-ray beam BB&apos; pierces the film at the back-reflection hole B, strikes the crystal at 0, and the transmitted beam leaves the camera at the transmission hole T. One of the diffracted X-rays intersects the film at a Laue spot L. The normal OP to the diffracting plane bisects the angle BOL between the incident and diffracted X-ray beams. The point P on the reference sphere can be located uniquely by the two orthogonal motions 6 and 8 on the two great circles ENWS and BPQT respectively. Because the Bragg angle 8 (= 90 - < BOP) is always less than 90 deg, P always remains in the hemisphere BENWS. Therefore, if every possible pole P is to be recorded on the same stereographic projection, it is necessary that the projection reference point be at T with the projection plane tangent to the sphere at B.* The great

Jan 1, 1963

By Harrison R. Cooper

This section will outline procedural, statistical, and model applications developed for specific problem solving and for specific applications in beneficiation processes. Iron Ore Processing Introduction of taconite as a basic raw material in the iron ore industry took place with application of high order technical resources for process development and engineering. This investment of resources encouraged computer utilization to maximize efficient use of capital. From this recognition, process control computers have been installed for operations use in the major taconite plants of the iron range. One of these installations, the Minntac Division of U. S. Steel at Mountain Iron, Minnesota, is described in the paper by Chase in these proceedings. Other computer techniques used in taconite processing are outlined by Tuttle, Ahlquist and Carlson, representing Erie Mining. In this volume Tuttle, et al. describe statistical methods for development of information in taconite beneficiation. Statistical methods used in iron ore processing are described by Volin in treating flotation data as outlined in prior proceedings of the symposia and in other publications. 1,2,3 Industrial Minerals The use of linear programming for feed blending at the Carlsbad operation of International Minerals and Chemicals was outlined by Nunnekoven in 1963.4 Subsequent application of this procedure at the Kingston phosphate operation in Florida was described by Loper. Continued development led to installation of an on-line computer in the Kingston plant which reached operational status in 1967.6,7,8 Application of an on-line computer to industrial mineral production accomplished at Kingston is regarded as a milestone in computer use development. Following this achievement, the Cominco potash beneficiation plant near Saskastoon in Canada was automated by installation of an on- line computer programmed to carry out direct digital control functions to effectively operate the plant by process computer. The procedures used in the Cominco operation are described by Madge in this volume. Development of a mathematical model

Jan 1, 1969

By K. O. Stamm, B. A. Rogers

Because it is the basis of the economically important operation of hardening steel by quenching, the A3 transformation in iron has been the subject of numerous investigations. Although the contributions to this subject are interesting, no general review will be given here. Readers who care to follow the matter further are referred to the comprehensive summary by Cleaves and Thompson,l which covers the literature to about 1935. Their references to 53 papers on the subject suggest that further investigation is hardly justifiable. However, considerable interest has devel oped recently concerning the reversibility of the transformation. From thermo-dynamic considerations, the transition ought to occur at the same point on heating or cooling, if the change of temperature is sufficiently slow. Yet all of the earlier investigators found a difference of several degrees. Burgess and Crowe,2 who used thermal methods, obtained average temperatures of 912" for Ac3 and 900°C. for Ar3 on electrolytic iron. Their data indicate a considerable range of temperature over which the change occurs, both on heating and on cooling. Terry3 measured the susceptibility in the critical range and estimated from the steepest parts of his curves that Ac3 came at 9I8° and Ar3 at 903°C. Ishiwara4 was one of the first investigators to report a shorter interval between the temperature of the change in the two directions. He measured the change of susceptibility of kaolin-coated samples of steel, in a hydrogen atmosphere, at rater of heating and cooling so low that about 3 or 4 hr. were required for the transformation to complete itself. His results show some variability between samples, but indicate that the difference between Ac3 and Ar3 is in the vicinity of 6°C. Roberts and Davey5 measured the space lattice in pure iron in the vicinity of 900°C. and concluded that a change occurs reversibly between 907&apos; 3" and 910" 3°C., probably between 907" and 910°C. Wells, Ackley, and Meh16 made dilatometric determinations of the Ac3 and Ar3 points in samples of hydrogen-treated carbonyl iron maintained under a vacuum. They used three rates of heating and cooling: 2°, ½°, and .?°C. per min. and found the spread between the two points decreased with low rates. At the slowest rate, the Ac3 transition occurred at 909° to 909. 5°C. and the Ar3 change at 907°C. in three of the samples believed to contain the lowest percentages of alien elements. They concluded that if the rate of temperature change and the content of alien eiements were low enough, the A3 transformation would be completely reversible at 909.50 + 1°C. The question of reversibility is an interesting one and when some iron with especially small percentages of alien elements became available the opportunity to conduct an investigation was welcomed. This iron was prepared by the Division of

Jan 1, 1942

By B. A. Rogers, K. O. Stamm

Because it is the basis of the economically important operation of hardening steel by quenching, the A3 transformation in iron has been the subject of numerous investigations. Although the contributions to this subject are interesting, no general review will be given here. Readers who care to follow the matter further are referred to the comprehensive summary by Cleaves and Thompson,l which covers the literature to about 1935. Their references to 53 papers on the subject suggest that further investigation is hardly justifiable. However, considerable interest has devel oped recently concerning the reversibility of the transformation. From thermo-dynamic considerations, the transition ought to occur at the same point on heating or cooling, if the change of temperature is sufficiently slow. Yet all of the earlier investigators found a difference of several degrees. Burgess and Crowe,2 who used thermal methods, obtained average temperatures of 912" for Ac3 and 900°C. for Ar3 on electrolytic iron. Their data indicate a considerable range of temperature over which the change occurs, both on heating and on cooling. Terry3 measured the susceptibility in the critical range and estimated from the steepest parts of his curves that Ac3 came at 9I8° and Ar3 at 903°C. Ishiwara4 was one of the first investigators to report a shorter interval between the temperature of the change in the two directions. He measured the change of susceptibility of kaolin-coated samples of steel, in a hydrogen atmosphere, at rater of heating and cooling so low that about 3 or 4 hr. were required for the transformation to complete itself. His results show some variability between samples, but indicate that the difference between Ac3 and Ar3 is in the vicinity of 6°C. Roberts and Davey5 measured the space lattice in pure iron in the vicinity of 900°C. and concluded that a change occurs reversibly between 907&apos; 3" and 910" 3°C., probably between 907" and 910°C. Wells, Ackley, and Meh16 made dilatometric determinations of the Ac3 and Ar3 points in samples of hydrogen-treated carbonyl iron maintained under a vacuum. They used three rates of heating and cooling: 2°, ½°, and .?°C. per min. and found the spread between the two points decreased with low rates. At the slowest rate, the Ac3 transition occurred at 909° to 909. 5°C. and the Ar3 change at 907°C. in three of the samples believed to contain the lowest percentages of alien elements. They concluded that if the rate of temperature change and the content of alien eiements were low enough, the A3 transformation would be completely reversible at 909.50 + 1°C. The question of reversibility is an interesting one and when some iron with especially small percentages of alien elements became available the opportunity to conduct an investigation was welcomed. This iron was prepared by the Division of

Jan 1, 1942

By R. M. Daelen

In recent years many new appliances have been introduced into German steel-works and rolling-mills for the purpose of improving working-methods, and of creating and maintaining increased production, and satisfying the ever-growing demand for metal of closely specified hardness, strength and form. One result of the improvements has been to aid very effectively in demonstrating the real superiority of ingot- over wrought-iron for almost every possible purpose, and in dispelling the last vestiges of prejudice unfavorable to the new metal. If, nevertheless, no marked decrease in the number of puddlingfurnaces has yet been noticed, the cause of their survival must be attributed to the greatly increased consumption of all kinds of ironmanufactures. Several large new works for the production of ingotiron are now, however, in course of erection in the Rhenish-Westphalian district, and upon their completion a rapidly diminishing output of wrought-iron may be anticipated. The present aim of all large works manufacturing ingot-iron is to work the molten blast-furnace pig into a finished product without any further fuel-consumption than is required to furnish steam for the rolling-mill. Though practice has established the feasibility of this principle, no works can yet point to its complete adoption, partly because of the limitations imposed by existing conditions and plant, and partly, also, on account of the highly-diversified character of the finished products. The Bessemer-works were the first to feel the influence of the basic process; but of recent years a similar influence has affected the open-hearth, and the owners of works possessing both a converterand an open-hearth plant are now seeking to arrange them for combined working, in charging as well as in casting. In small works the basic-lined reverberatory furnace is constantly gaining ground over the old puddling-furnace. The small basic converter, on the

Jan 1, 1891

By John Charles

The Engineering Method. By John Charles Lou11sbul.y Fish. Stanford University Press. 1950. 186 P. $3.-This book is about the "professional habit often referred to . . . . as &apos;the scientific method&apos; . . ." It formulates for students the system of logic and reasoning that is the mark of the practicing engineer. The three chapters are, "The Method of Engineering", "Application of the Engineering Method" and "Uncertainties in Engineering." They cover logic and reasoning, terms, nontechnical problems, practical conditions controlling the engineering method, inescapable uncertainties and the method of coping with them. The author is emeritus professor of civil engineering at Stanford. The material presented here formed chapters 9, 10, and 11 of The Engineering Profession, by Hoover and Fish, second edition 1950. Elements of Ore Dressing. By Arthur F. Taggart. John Wiley & Sons, Inc., New York, 1950. $10.- A modern and practical introduction to the subject by the noted author of the Handbook of Mineral Dressing. The philosophy that a mill and all its parts comprise a single treatment process is a continuing theme in the book. Professor Taggart covers hand picking, screening, filtration, and electrical concentration. After introducing sedimentation, he takes up acceleration in free-settling, hindered-settling, sink-float, jigging, film and trough concentrators and shaking concentrators. A discussion of organic chemicals in flotation is followed by a detailed treatment of flotation. Final chapters deal with primary crushing, secondary crushing, grinding, transport, and controls and flowsheets.

Jan 3, 1951

By L. M. Pidgeon, K. T. Aust

There has been considerable interest in the possible use of titanium in magnesium alloys.&apos; Zirconium has shown some promise in this connection2 and its general similarity with titanium suggests that the latter might act in a similar manner. A literature survey revealed that quantitative data on the Mg-Ti system was unavailable. Several patents3 have claimed that titanium additions from 0.2 to 4 pct to magnesium alloys were possible, but no mention was made as to the form in which the titanium existed in the alloy. Kro114 succeeded in introducing only traces of titanium into magnesium by bubbling TiCl4 through the metal under argon or by reacting it with sodium titanium fluoride. The application of theoretical data given by Carapella5 based on Hume-Rothery&apos;s principles, involving atomic size factor, crystal structure, valency and the electro-chemical factor, suggests that a Mg-Ti alloy is a favorable case, and the system appeared to warrant experimental examination. Experimental Procedure and Results THERMAL ANALYSIS If titanium is appreciably soluble in magnesium, a change in the melting point of the magnesium might be detectable using standard cooling curve methods. Magnesium was melted in graphite crucibles under an argon atmosphere, the assembly being enclosed in a silica tube. Graphite thermocouple protection tubes served also to stir the melts. The apparatus was very similar to Fig 1, with the addition of a refractory and baffle system to prevent undue heat losses from the top of the crucible. Chromel-alumel thermocouples were calibrated using Al of 99.97 pct purity. Dominion Magnesium Limited sup- plied redistilled high purity magnesium of the analysis given above. Titanium was added in three different forms: 1. Titanium powder —100 mesh, from the Titanium Alloy Manufacturing Co., Niagara Falls, N. Y. 2. Sheet titanium from the U.S. Bureau of Mines, produced by Mg reduction of TiCl4. 3. Magnesium —50 pct titanium master alloy from Metal Hydrides Inc., Beverly, Mass. The melting point of the high purity magnesium used was measured experimentally as 651.0°C. More than a dozen tests were conducted using titanium from the three sources referred to above, in calculated additions up to 20 pct titanium, at temperatures between the melting point and 1000°C and holding periods up to 6 hr. In no case was evidence obtained of solubility of titanium in magnesium, using inverse-rate and time-temperature curves. The melting point of the magnesium was unchanged within the accuracy of measurement, namely -+0.5°C; and no other thermal arrests were detected. Metallographic investigation of the thermal analysis billets indicated that the titanium additions were apparently mechanically entrapped in the magnesium in segregated areas. Consequently, these samples were not analyzed for titanium. The master alloy proved to be a mechanical mixture of titanium particles in a magne- sium matrix. These results indicated that the titanium solubility, if such existed, could not be obtained by the usual thermal methods. X RAY DIFFRACTION INVESTIGATION In an effort to detect solubility of titanium in magnesium, samples were investigated using both the Debye-Scherrer and the Focusing Back-Reflection methods. Filings from samples of the thermal analysis billets and from pure magnesium were annealed in argon one hour at 350°C to relieve mechanical strain. Measurements made of the interplanar spacings showed no difference between the Mg-Ti samples and pure magnesium. The interplanar spacings could be measured to within 0.0002A, and the greatest variation found was 0.0004A, in the back-reflection method. The diffraction lines for magnesium were not shifted by the titanium additions indicating that the solid solubility of titanium in magnesium is of a very low order—less than 0.5 pct. From both diffraction methods, a d or interplanar spacing of 0.817A was obtained for the redistilled high purity magnesium. This latter value is not given in the standard X ray diffraction cards for magnesium metal or vacuum distilled magnesium. Theoretical calculations for a close-packed hexagonal space lattice for magnesium indicate that the planes {2134) should give a line which was found. The relative intensity for this reflection at 0.817A is slightly less than that at 0.870k for magnesium. SOLUBILITY OF TITANIUM IN LIQUID MAGNESIUM The Mg-Mn system was examined by Grogan and Haughton6 who were

Jan 1, 1950

By W. C. Leslie

W. C. Leslie (Edgar C. Bain Laboratory for Funda mental Research)—This investigation, with its com bination of high-purity metal, calorimetry, and metallography, will serve as a model for annealing studies for a long time to come. The evidence for a competition between recovery and recrystalliza-tion is particularly convincing. The demonstration of edge-nucleated recrystallization was so clear that it may obscure the necessity for other types of "nucleation" sites; otherwise, single crystals of aluminum could not be recrystallized after cold work. At least three types of sites have been found to operate in iron: 1) high-angle boundaries, probably in the same manner as in aluminum, 2) matrix sites, 3) inclusions or second-phase particles. In each instance, the cells developed during cold work and perfected during recovery are the "nucle for recrystallization. Observations by ourselves and others of the dislocation structure of cold-worked metals and of the structural changes that occur during annealing have led us to doubt the validity of the basic assumption of the Lucke-Detert theory, and of the modification developed by Gordon and Vandermeer, that during recrystallization of a metal containing foreign elements in solid solution a high-angle boundary is ad vancing into a cold-worked matrix having a random distribution of solute atoms. We contend that an es sential part of the cold-working and annealing of solid solution alloys is the trapping of solute atoms by the low-energy "wells" afforded by individual dislocations and by dislocation arrays. If cells are formed during cold work, the cell walls are stabilized by this concentration of solute atoms. Thus, solutes inhibit recrystallization not only by decreas-ing the rate of high-angle boundary migration, but also by preventing the formation of high-angle boundaries by subgrain growth or coalescence, i.e., solutes can inhibit both "nucleation" and growth. In addition to stabilizing the dislocation Structure, the solute-dislocation interactions may produce clusters of solute atoms which are not as readily assimilated into the recrystallized grains as are individual solute atoms. There is an additional complication. The dislocation structure formed upon cold working a dilute solid solution may not be the same as that formed during cold working of the pure solvent metal. The solute can either enhance or minimize the formation of cells during cold working. Both effects have been observed in binary alloys of iron. The annealing process is inextricably connected with the mechanisms of strain hardening and solid solution hardening. Although the correlation between experimental boundary migration rates and the predictions made from the theoretical equations are impressive, it should be mentioned that in at least four other instances (Pb-Ag and pb-Au,15, Fe-Mn,16, Fe-Mo)17 the agreement was rather poor. In brief, while it is probable that the migration of high-angle boundaries is held back by solutes in the manner described, this is only a partial explanation of the total effect of solutes upon recrystallization of cold-worked alloys. Paul Gordon and R. A. Vandermeer (author&apos;s reply)— The authors first wish to thank Dr. Leslie for his compliments of this work. It is perhaps worth pointing out that some of Dr. Leslie&apos;s remarks are directed toward subject matter covered in two earlier papers in our work.18,19 We agree with Dr. Leslie&apos;s main contention that the exact nature of the metal structure in the vicinity of a boundary should have an effect on the boundary migration. The theory of Lucke and Detert does not take such detail into account, nor does it account for orientation effects on the migration rates. We assume that since our data checks the theory so well, the effects of detailed structure are statistically averaged out by the polycrystalline techniques used just as are the effects of orientation factors.

Jan 1, 1963

By W. Denham Verschoyle

IN designing a pocket instrument whereby any given horizontal or vertical angle may be closely approximated, the following points should be kept in view, if general utility is aimed at 1. The instrument should be light and compact, so that it can be carried in the pocket, or in a sling. 2. It should be capable of observing any angle whatever, horizontal or vertical. 3. Since time is often an important consideration in making a preliminary survey, it should be capable of giving the horizontal and vertical angle at one observation. I do not know of any instrument that will fulfill these requirements, except the one here described. Where the depression- or elevation-angle of the distant object, whose bearing is required, exceeds 50 or 60 degrees, it becomes difficult or impossible with a prismatic compass, for instance, to obtain accurate results; and since it frequently happens, particularly in mining, that much work requires to be done beyond that limit, it is obvious that an instrument which can be used to observe a high angle just as easily as a low one, if not absolutely a necessity, will at least be a great convenience. How this " pocket transit " attains to the required degree of universality will be understood from the diagram, Fig. 1, in which B is a beveled, graduated circle, attached to and freely revolving about the center of the magnet A. Light falling on B is reflected through a window in F (the compass-box), along the line AC, and is again reflected back to the eye at D by the prism C. By a simple arrangement, the sight-line DCE can be completely revolved in the vertical plane DE, which is normal to AC. It is clear, then, that no matter through what vertical

Jul 1, 1907

By E. W. Davis

THIS nation has been depending upon the Lake Superior iron ranges for most of its iron ore requirements for over half a century. Furthermore, it can continue to draw the major portion of its ore requirements from the same source for another century or more, but to accomplish this, great changes must take place in the present ore mining industry. Preliminary preparations for these changes are now underway and in the next few years decisions of far-reaching importance must be made. But to understand the situation, it is first necessary to know something of the nature and occurrence of the Lake Superior iron formation. So far as is known, the merchantable grades of iron ore remaining in the various Lake Superior ranges are as shown in Table 1, which shows that

Jan 1, 1947

By F. C. Schrader, Alfred H. Brooks

Last fall (1899) we had the good fortune to be able to spend a few weeks in the new placer gold-mining region of Alaska, which is known as the Nome region. Cape Nome, after which the region has been named, and which forms the southeastern corner of the Nome Mining District, is an unimportant promontory on the southern coast of the Seward Peninsula (see map, Fig. 1). The name Seward has recently been given to the great peninsula which forms the northwestern extremity of Alaska. To the north of it is the Arctic ocean, to the south Bering sea, while its wesbernmost extremity, Cape Prince of Wales, is separated from the Asiatic coast by the Bering straits. The coast line of the peninsula is of a cuspate character, consisting of a succession of sandy, crescent-shaped beaches and rocky headlands. The interior has been but little explored; but we know that it is comparatively rugged, the higher mountain peaks rising probably from 4000 to 5000 feet in elevation. The mountains have an easterly and westerly trend, and the water-shed between the two oceans probably nearly bisects the peninsula. At Golofnin bay, the southeastern part of the Seward peninsula, some spruce is found, but to the west the region is entirely timberless, except for a sparse growth of stunted

Jan 1, 1901