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By H. I. Aaronson

The nucleation of pearlite at proeutectoid ferrite is inhibited, to an increasing extent, at the following locations: At twin boundary-nucleated ferrite, between closely spaced ferrite sideplates, and at intragranular plates. These effects are discussed in terms of the influence of transformation strain energies and of the interfacial free energy of austen-ite:ferrite boundaries on the rate of pearlite nucleation. The growth of pearlite into the interiors of austenite grains from the region of the grain boundaries is markedly restricted when low reaction temperatures and large austenite grain sizes permit the development of interlocking networks of intragranular ferrite plates. PREVIOUS investigators have made extensive studies of the interactions which occur between the proeutectoid ferrite and the pearlite reactions from the viewpoint of the mechanisms through which pearlite interferes with the nucleation and growth of proeutectoid ferrite.1-3 In the present investigation, the processes through which proeutectoid ferrite (hereafter termed simply "ferrite") can reduce the rate of formation of pearlite have been explored in some detail. A steel with a relatively low carbon content, in which the ferrite reaction can compete successfully with the pearlite reaction over a wide range of reaction temperature, and exceptionally coarse-grained specimens, which further emphasize the role of the ferrite reaction, have been employed for most of this work. A brief examination also has been made, however, of the effects of smaller austenite grain sizes upon these processes. Experimental Procedure The steel employed had the following composition: 0.29 pet C, 0.76 pet Mn, 0.25 pet si, 0,007 pet S, and 0.005 pct P. This alloy was homogenized for 48 hr at 1250°C. The investigation was performed

Jan 1, 1959

By F. P. Dewey

The first systematic attempt of the National Museum to gather material representing the economic geology and metallurgy of the country was made in connection with the Centennial Exhibition. The department may be considered as having originated then, althongh it was not formally inaugurated until December, 1882. Previous to the Centennial, all the illustrations of economic geology had been included in the mineral collection, and the illustrations of metallurgy were so very few that they had also been included with the minerals. When the museum began its collections for the Centennial, the subject of the mineral resources of tile United States was placed in the hands of Professor Wm. P. Blake, who was eminently fitted to undertake the work by his experience at various international exhibitions and his extensive acquaintance with the mining industry of the country. Professor Blake prepared a broad and exhaustive plan for this purpose, and the very large collection shown at Philadelphia was well calculated to set forth the vast mineral wealth of the country. The history of the department proper may conveniently be divided into three periods : first, the formative period, during which the Centennial material was mainly administered upon, ending Jnly 1, 1884, with the beginning of the preparation for the New Orleans Exposition; second, the New Orleans Exposition period, from July 1, 1884, to June 30, 1887, during which the collections for the New Orleans Exposition were made, exhibited at New Orleans, returned to Washington, and installed permanently in the museum; third, the southwest-court period, from July 1, 1887, to October 1, 1889, during which the collections were arranged in the southwest court of the museum.

Jan 1, 1891

By R. W. Raymond

In my former paper (Bans., xii., 410) I quoted the ruling of Judge Hallett, of Colorado, in the "Iron-Smuggler" case, tried before him in June, 1882. Under his charge, the jury in that case found for the defendants, practically declaring that the deposit on the outcrop of which the Iron Silver Mining Company's claim was located was not a " lode," or else that the portion of it within that claim was not the apex. The case was appealed, and the decision of the Supreme Court, given in February, 1886, is reported in 116 U. S. Reports, p. 529. It simply declares that there is nothing in the charge of Judge Hallett to warrant the setting aside the verdict. The definition of a legal lode given in that case, and quoted in my paper at the page above-named, is perhaps the best of several which Judge Hallet has pronounced. That is to say, his earlier definition, that " a lode or vein is a body of mineral, or mineral-bearing rock, within defined boundaries in the general mass of the mountain," is here accompanied with further explanations, which relieve it from the requirement on one hand, that the body shall be continuously ore-bearing if it he only well-defined, and, on the other hand, that the boundaries shall be well-defined if the ore-bearing body be proved to exist. So far as this particular case is concerned, the approval of this ruling by the Supreme Court merely prevents any re-hearing as to the face. Undoubtedly, the evidence was conflicting; and the jury chose to believe, for the purpose of that occasion, the " experts " who

Jan 1, 1887

By V. R. Garfias

Although the work on which this paper is based was carried on by the writer as Special Commissioner of the Petroleum Department of the Mexican Government, the opinions expressed are only his personal views for which the Mexican Government can in no way be held responsible. Notwithstanding that the appointment covers all phases of the so-called petroleum question, as the one question of immediate importance was that relating to taxation, it was decided to devote all the time to this phase of the work. The present report has been divided into two closely related parts, the first dealing with the production and marine transportation of Mcxican petroleum, and the second, with the Mexican taxation on petroleum and its products. The writer wishes to acknowledge the loyal cooperation rendered by Mr. M. C. Ehlen, who had charge of the statistical work, and by Miss S. Stern and Messrs. E. P. Heiles and J. E. Morrissey. The aim throughout the work has been to pave the way for a thorough understanding between the Mexican Government and the oil operators and to present a true and clear statement of facts relating to the questions at issue. Mexican Oil Fields Development The salient features in the development of the Mexican oil fields may be summarized as follows: 1901. First commercially productive well in Ebano field. 1902. Tehuantepee field came in; Diaz Government granted concession to Pearson & Son on practically all Federal lands along the Gulf of Mexico. 1907. First producing well in the Furbero field. 1908. Dos Bocas well caught fire, advertising tremendous productivity of Southern oil fields of Mexico.

Jan 1, 1921

By William Fink

THE investigation of the phase relations of high-purity aluminum-base alloys is a part of the fundamental research program of the laboratories of the Aluminum Company of America. The results of a number of binary and ternary systems have previously been published in the transactions of this society. The aluminum end of the binary aluminum-titanium system has been studied. This system has received relatively little attention. To the authors' knowledge, there are two previous papers on this subject. E. van Erckelens1 determined the constitutional diagram reproduced in Fig. 1. .According, to this diagram, the liquids represents the separation of TiAl4 (Ti = 30.7 per cent.). He concluded that this is the composition of the compound, because in his work the eutectic horizontal terminated at 30.7 per cent. titanium and the metallographic examination of a sample of this composition revealed only one phase. According to the constitutional diagram developed by W. Manchot and A. Leber,2 reproduced in Fig. 2 from data given in their article, the liquidus represents the separation of the compound TiAl3 (Ti = 37.2 per cent. ). The composition of the compound was derived in a manner similar to that utilized by van Erckelens. Moreover, Manchot and Leber confirmed the composition of the compound by analysis of the constituent left as a residue after dissolving the alloys in weak sodium hydroxide solution. Although these are the only publications describing the constitution of the system, other investigators have studied the composition of the titanium compound. L. Wöhler3 says that there is a compound TiAl3 which was later confirmed by W. Manchot and P. Richter4 and by

Jan 1, 1931

By Spencer Cragoe

I have read with much interest the elaborate and able paper of Messrs. Granger and Treville on the Mining Districts of Colombia, presented at the Atlantic City Meeting (ante, p. 33). Going into detail, however, as the paper does—and particularly with reference to the department of Antioquia, I am somewhat surprised that the property of the Frontino and Bolivia Company, probably one of the richest and most extensive in Colombia, should come off with such scant notice. The entire property embraces an area of some 28 square miles, and is situated at a distance of about 2 leagues from Remedios—after Medellin probably the most important town of the Department—and lying in approximately '7° N. latitude. The neighborhood of Remedios has been long celebrated for its production of the precious metal. Alluvial gold in large quantities has been obtained from the vicinity for upwards of two centuries; and even to-day a large proportion of the population finds a comfortable livelihood, during the dry season, in washing the sands of various rivers, notably the Rio Porce; while the amount of gold, in the form of nuggets, brought almost daily to Remedios and other points, from streams in the immediate neighborhood, is astonishing. These nuggets vary much in size. The majority, of course, are small, but larger ones are by no means scarce. I have been considerably surprised at the amount and value of the trade thus transacted between natives and merchants of the various towns. The property owned by the Frontino and Bolivia Company has been, I believe, for the larger part of the present century,

Jan 1, 1899

By J. J. Jakosky

The fundamental hydrodynamic principles governing the production of oil from wells have been carefully studied and evaluated by many investigators. These prior studies are quite complete and cover virtually the entire field of oil production and recovery.' One of the most important measurements in production studies is that of the bottom-hole pressure at various rates of production.2 It is the purpose of this paper to outline the technique and economics of fluid-level measurements as applied to pumping wells and to review briefly other methods for obtaining bottom-hole data. The applications of bottom-hole pressure or fluid-level measurements are based on simple hydrodynamic principles. Under equilibrium conditions, pbh = hd + pg + pch [1] when pbk = bottom-hole pressure, Ib. per sq. in. absolute, h = height of fluid in well, ft., d = average fluid density, Ib. per sq. in. per foot, p, = weight of section of gas column 1 in, square from fluid level to casinghead, Pch = casinghead pressure, Ib. per sq. in. absolute. In words, equation 1 states that the bottom-hole pressure is equal to the weight hd of the column of fluid plus the weight of the column of gas between the fluid and the casinghead plus the casinghead pressure. At moderate rates of flow, the rate of production is approximatcly proportional to the difference between the reservoir, or static bottom-hole. pressure and the flowing or producing pressure; i.e.: Q = c(pr - pbh) [2] pr = the reservoir pressure, c = the constant of proportionality. However, at production rates approaching zero and also at high rates the proportionality may break down. By combining equations 1 and 2 the

Jan 1, 1939

By J. J. Jakosky

The fundamental hydrodynamic principles governing the production of oil from wells have been carefully studied and evaluated by many investigators. These prior studies are quite complete and cover virtually the entire field of oil production and recovery.' One of the most important measurements in production studies is that of the bottom-hole pressure at various rates of production.2 It is the purpose of this paper to outline the technique and economics of fluid-level measurements as applied to pumping wells and to review briefly other methods for obtaining bottom-hole data. The applications of bottom-hole pressure or fluid-level measurements are based on simple hydrodynamic principles. Under equilibrium conditions, pbh = hd + pg + pch [1] when pbk = bottom-hole pressure, Ib. per sq. in. absolute, h = height of fluid in well, ft., d = average fluid density, Ib. per sq. in. per foot, p, = weight of section of gas column 1 in, square from fluid level to casinghead, Pch = casinghead pressure, Ib. per sq. in. absolute. In words, equation 1 states that the bottom-hole pressure is equal to the weight hd of the column of fluid plus the weight of the column of gas between the fluid and the casinghead plus the casinghead pressure. At moderate rates of flow, the rate of production is approximatcly proportional to the difference between the reservoir, or static bottom-hole. pressure and the flowing or producing pressure; i.e.: Q = c(pr - pbh) [2] pr = the reservoir pressure, c = the constant of proportionality. However, at production rates approaching zero and also at high rates the proportionality may break down. By combining equations 1 and 2 the

Jan 1, 1939

By W. F. Holbrook, C. E. Wood, E. P. Barrett

The high-frequency laboratory induction furnace with a rotating liquid crucible enables research workers to conduct certain investigations heretofore very difficult or impossible to realize because vessels are not obtainable that are capable of resisting the physical conditions or the chemical actions to which they are subjected. Applications for patents covering commercial uses of centrifugal liquid crucibles were filed in the United States in 1919,' in France in 1925, in the United States and Germany in 1926,2 and in France in 1927.3 In 1928, Schuette and Maier,4 of the Bureau of Mines, reported the construction of a whirling table beneath a high-frequency induction furnace. Shape and Size of Centrifugal Liquid Crucibles When a vessel containing a liquid is rotated, the inner surface of the liquid takes the shape of a paraboloid under the simultaneous action of centrifugal force and gravity. The internal dimensions of the paraboloid rotating liquid crucible are governed by the diameter of the container and its speed of rotation. Melted Wood's metal was poured into cylinders 2 1/2 in. in diameter, which were rotated at 180, 300, and 468 r.p.m. When the metal was solid, a slurry of plaster of Paris was added, and rotation continued until the plaster had set. Fig. 1, a photograph of sections of the cylinders, shows the effect of speed of rotation of the containers upon the shape of the inner surface of the rotating liquid crucibles. Types of Furnaces Three types of high-frequency induction laboratory furnaces using liquid-metal crucibles were designed and constructed by the Blast

Jan 1, 1939

By W. F. Holbrook, C. E. Wood, E. P. Barrett

The high-frequency laboratory induction furnace with a rotating liquid crucible enables research workers to conduct certain investigations heretofore very difficult or impossible to realize because vessels are not obtainable that are capable of resisting the physical conditions or the chemical actions to which they are subjected. Applications for patents covering commercial uses of centrifugal liquid crucibles were filed in the United States in 1919,' in France in 1925, in the United States and Germany in 1926,2 and in France in 1927.3 In 1928, Schuette and Maier,4 of the Bureau of Mines, reported the construction of a whirling table beneath a high-frequency induction furnace. Shape and Size of Centrifugal Liquid Crucibles When a vessel containing a liquid is rotated, the inner surface of the liquid takes the shape of a paraboloid under the simultaneous action of centrifugal force and gravity. The internal dimensions of the paraboloid rotating liquid crucible are governed by the diameter of the container and its speed of rotation. Melted Wood's metal was poured into cylinders 2 1/2 in. in diameter, which were rotated at 180, 300, and 468 r.p.m. When the metal was solid, a slurry of plaster of Paris was added, and rotation continued until the plaster had set. Fig. 1, a photograph of sections of the cylinders, shows the effect of speed of rotation of the containers upon the shape of the inner surface of the rotating liquid crucibles. Types of Furnaces Three types of high-frequency induction laboratory furnaces using liquid-metal crucibles were designed and constructed by the Blast

Jan 1, 1939

By Carle Hayward

THIS work was first undertaken in the metallurgical laboratory of the Massachusetts Institute of Technology in 1907 by L. A. Dickinson, E. Phelps, and V. S. Rood, under the author's direction. They attempted to determine the diagram for the system Cu2S-NiS, but several inexplicable results were obtained. The following year, P. H. Mayer with Mr. Dickinson carried, on some experiments with nickel sulphide and found that the molten material slowly lost sulphur until it reached a composition corresponding to the compound Ni3S2, established by Bornemann.1 At this point the composition remained stable. The freezing points of the mixtures gradually fell off with the loss of sulphur. Since the above facts seemed to explain the erratic results obtained in the first experiments, Mr. Mayer with F. Jaeger attempted in 1910 to establish a correct equilibrium diagram for the Cu2S-Ni3S2 series. They prepared pure Cu2S and Ni3S2 and determined the cooling curves for various mixtures. The fusions were made in a platinum resistance furnace and the temperatures were measured with a platinum-iridium thermocouple connected with a Sullivan galvanometer. The curve was established for mixtures containing more than 40 per cent. Cu2S, but they were unable to determine certainly the direction of the curve beyond that point. Nothing further was attempted with this series until the present year, when the work was carried to a successful conclusion with the assistance of A. Butts, Jr., and E. H. Weil. The results of this work are given in the following pages.

Jan 1, 1914

By Fred C. Bond

IN crushing and grinding the larger particles are more exposed to the work input. They absorb most of the work and protect the smaller neighboring particles from destructive contact with the crushing surfaces or grinding media. The importance of this exposure differential upon the reduction efficiency and product size distribution has long been recognized. Unfortunately, there has heretofore been no direct method of evaluating it, and such indirect methods as observing the slope of the plotted product size distribution line have been used as an indication. In this presentation the Third Theory of Comminution' has been used, together with the exponential formula for size distribution, to evaluate the ex- posure ratio and exposure constant and to illustrate examples of their utility in crushing and grinding applications. The exposure ratio Er varies from zero to unity. It is zero when the product particles are all of one size, and it is unity when the work input has been equally distributed among all particle sizes. It can readily be found from screen analyses plotted according to the Third Theory. The exposure constant K is derived from the reciprocal of the exposure ratio Er. It permits more consistent predictions of size distributions and evaluation of many factors concerned in size reduction operations. The Third Theory1 states that the specific work input required for size reduction is inversely proportional to the square root of the product size less the work required to form the feed. When P represents the diameter in microns which 80 pct of the product passes, F is the size 80 pct of the feed passes, Wi

Jan 1, 1958

By P. M. Budge, William L. Fink, Kent R. Van Horn

The investigation of the phase relations of high-purity aluminum-base alloys is a part of the fundamental research program of the laboratories of the Aluminum Company of America. The results of a number of binary and ternary systems have previously been published in the Transactions of this society. The aluminum end of the binary aluminum-titanium system has been studied. This system has received relatively little attention. To the authors' knowledge, there are two previous papers on this subject. E. van Erckelensl determined the constitutional diagram reproduced in Fig. 1. According to this diagram, the liquidus represents the separation of TiA14, (Ti = 30.7 per cent.). He concluded that this is the composition of the compound, because in his work the eutectic horizontal terminated at 30.7 per cent. titanium and the metallographic examinalion of a sample of this composition revealed only one phase. According to the constitutional diagram developed by W. Manchot and A. Leber,² reproduced in Fig. 2 from data given in their article, the liquidus represents the separation of the compound TiA13 (Ti = 37.2 per cent. ). The composition of the compound was derived in a manner similar to that utilized by van Erckelens. Moreover, Manchot and Leber confirmed the composition of the compound by analysis of the constituent left as a residue after dissolving the alloys in weak sodium hydroxide solution. Although these are the only publications describing the constitution of the system, other investigators have studied the composition of the titanium compound. L. WÖhler3 says that there is a compound TiA13 which was later confirmed by W. Manchot and P. Richter4 and by

Jan 1, 1931

By C. H. Mathewson

BERYLLIUM, magnesium, zinc and cadmium, together with mercury, constitute a coherent sub-group of the periodic system and these metals, excepting mercury; have been studied in sufficient detail by the new X-ray diffraction methods to prove their common adherence to the hexagonal close-packed type of crystal structure with a progressive increase in axial ratio as we pass through the group from beryllium to cadmium. The first four columns of Table 1 summarize the data on crystal structure of these metals reported in the International Critical Tables.1 The last two columns are based on results obtained in the present investigation. TABLE 1.-Lattice Constants and Twinning Law of the Be-Cd Group of Hexagonal Metals Dimensions of Unit Axial Cell, A Ratio Description of Twinning Element a° c° (c°/a°) Composition Axis Plane Beryllium 2.28(3) 3.60(7) 1.58 {1012} Probably 1 {1012} Magnesium 3.22 5.23 1.621 ,1 {1012} Zinc 2.65(7) 4.94(8 1.86(2) 11012 } 1 {1012) Cadmium 2.98 5.63 1.88(5) {1012} Probably 1 {1012} Twinning has often been observed in zinc and cadmium. The general aspects of this twinning are abundantly illustrated by photomicrographs, diagrams, etc., in the papers by Romig, and Mathewson and Phillips reported to this Institute in 1927.2. A determination of the composition

Jan 1, 1928

By G. E. McElroy

Much attention has been directed to mine-air flow in recent years, more especially in Great Britian where there is frequent reference to a theory of fluid flow developed by English engineers. Briefly stated, this theory is that for similar passages of the same relative roughness, in which fluid flow occurs, the conditions of flow are exactly the same for W D V equal values of the product where W = density of the fluid, D = diameter of the passage through which flow occurs, V = mean velocity of flow, and p = absolute viscosity of the fluid flowing. This, the "Reynolds Criterion" of fluid flow, had its origin in the work of Reynolds1 more than 40 years ago. Later, Rayleigh2 amplified the theory which has been conclusively proved for small pipes by the experiments of Stanton and Panne13 over a large flow range, and by Lacey4 over a somewhat more limited range. Concordant results on small pipes have also been obtained by numerous other investigators with single fluids over more or less limited ranges of flow. According to this theory, results in one medium, such as water, are immediately applicable to another, such as air; and experimental results on models are (theoretically, at least) applicable to full-scale designs. This is of great importance in aeronautics and can be of considerable value in mine ventilation research. Hodgson, in a recent paper,6 has outlined the application of this theory to mine-air flow and recent English experiments6 on the resistance of a timbered mine airway have been expressed in this form.

Jan 1, 1927

By Frank Foote, Willard L. Bruner, Eric R. Jette, Y. New york

The alloys of gold and iron were investigated in 1907 by Isaac and Tammann,l who determined the thermal diagram for the entire system by thermal analysis and microscopic examination. They also reviewed the previous literature. Since that time the present authors have been able to find only two additional references. Guertler and Schulze2 examined the electrical resistance of iron alloys containing up to 40 per cent by weight of gold between 0" and 200" C.; the alloys were in the form of wires. The main result of this work was to confirm the solid solubility limit found by Isaac and Tammann; namely, about 20 per cent Au. More recently, Shih3 has examined the magnetic properties of gold alloys containing up to 10 weight per cent iron and particularly the range below 5 per cent. The alloys in the lower range were found to be paramagnetic; the 10 per cent alloy was ferromagnetic. The present investigation was undertaken to determine the solid solubility limits at various temperatures, particularly below the a-y transformation point of iron, since these solubilities are of some importance in connection with the working of the alloys in the manufacture of certain "grey" and "blue" golds. Materials and Methods The gold was obtained from the U. S. Metals Refining Co. and contained 99.99+ per cent Au. The electrolytic iron had been annealed in hydrogen and contained impurities as follows: P, 0.035; Si, 0.001; S, C, Mn, Cu, each 0.01 per cent. Weighed quantities of the two metals were placed in small crucibles lined with pure sintered MgO; a saturated solution of magnesium nitrate

Jan 1, 1934

By James W. Neill

The occurrence of minerals of nickel and cobalt at Mine La Motte is probably known to every mineralogist. I will not attempt to describe these minerals, but, before entering on my subject, will briefly mention the ores, etc., which call for metallurgical treatment and enter into the composition of our mattes. Our staple lead-ore, the dressed galena, is the chief source of nickel and cobalt. It carries but a small percentage of these metals, viz.: 0.2 to 0.3 percent. usually, though when much copper pyrites is contained in the gangue, the amount of nickel and cobalt may be as great as 1.0 to 1.5 per cent. Next in importance is the ((middle product" of the dressingworks, consisting of the sulphides of iron (and copper) with gangue and galena. This usually carries 20 to 23 per cent. of lead, 0.5 to 1.0 per cent. of copper and 2.5 to 3.5 per cent. of nickel and cobalt. A larger percentage of copper always carries with it an increase of nickel and cobalt. In some few cases 12 to 15 per cent. of copper gives 6.5 to 8.0 per cent of these metals. Resides these products of the dressing-works, there is a small quantity of true nickel-cobalt-ore

Jan 1, 1885

By R. W. Ph. D. Raymond

PROFESSOR W. P. BLAKE, in a note to his Catalogue of California Minerals, pointed out that the mining districts of the Pacific slope are arranged in parallel zones, following the prevailing direction of the mountain ranges. This interesting generalization has been more fully illustrated and connected with the geological history of the country by Mr. Clarence King, who sums tip the observed phenomena as follows: "The Pacific coast ranges upon the west carry quicksilver, tin, and chromic iron. The next belt is that of the Sierra Nevada and Oregon Cascades, which, upon their west slope, bear two zones, a foot-hill chain of copper mines, and a middle line of gold deposits. These gold veins and the resultant placer mines extend far into Alaska, characterized by the occurrence of gold in quartz, by a small amount of that metal which is entangled in iron sulphurets, and by occupying splits in the upturned metamorphic strata of the Jurassic age. Lying to the east of this zone, along the east base of the Sierras, and stretching southward into Mexico, is a chain of silver mines, containing comparatively little base metal, and frequently included in volcanic rocks. Through Middle Mexico, Arizona, Middle Nevada, and Central Idaho is another line of silver mines, mineralized with complicated association of the base metals, and more often occurring in older rocks. Through New Mexico, Utah, and Western Montana lies another zone of argentiferous galena lodes. To the east, again, the New Mexico, Colorado, Wyoming, and Montana gold belt is an extremely well-defined and continuous chain of deposits." These seven longitudinal zones or chains of mineral deposits must

Jan 1, 1873

By R. W. Raymond

PROFESSOR W. P. BLAKE, in a note to his Catalogue of California Minerals, pointed out that the milling districts of the Pacific slope are arranged in parallel zones, following the prevailing direction of the mountain ranges. This interesting generalization has been more frilly illustrated and connected with the geological history of the country by Mr. Clarence King, who sums up the observed phenomena as follows : " The Pacific coast ranges upon the west carry quicksilver, tin, and chromic iron. The next belt is that of the Sierra Nevada and Oregon Cascades, which, upon their west slope, bear two zones, a foot-hill chain of copper mines, and a middle line of gold deposits. These gold veins and the resultant placer mines extend far into Alaska, characterized by the occurrence of gold in quartz, by a small amount of that metal which is entangled in iron sulphurets, and by occupying splits in the upturned metamorphic strata of the Jurassic age. Lying to the east of this zone, along the east base of the Sierras, and stretching southward into Mexico, is a chain of silver mines, containing comparatively little base metal, and frequently included in volcanic rocks. Through Middle Mexico, Arizona, Middle Nevada, and Central Idaho is another line of silver mines, mineralized with complicated association of tli6 base metals, and more often occurring in older rocks. Through New Mexico, Utah, and Western Montana lies another zone of argentiferous galena lodes. To the east, again, the New Mexico, Colorado, Wyoming, and Montana gold belt is an extremely well-defined and continuous chain of deposits." These seven longitudinal zones or chains of mineral deposits must

By J. E. Metcalfe

Proceedings of the Fourth Empire Mining and Metallurgical Congress, Great Britain 1949. Part II published at the Offices of the Congress in London, England, 1139 pp. The price of these proceedings is £ 2. The parts may be purchased separately at a cost of £ 1 each.-Part I of this book covers a report of the organizing committee, the inaugural meeting and presidential address, banquet at Guildhall, welcome by Sir Richard Livingstone at Oxford. and final session. Technical session and papers are also covered in Part I. Part II covers such topics as coal, present-day trends in mineral dressing and metallurgy. Mining Engineer's Survey Manual. By J. E. Metcalfe. Published for "Mine & Quarry Engineering" by Electrical Press, London, 1951. 341 pp., illus., charts, diagrs., tables, 8 ¾ x 5 1/ in., cloth, 30s., available from Percival Marshall & Co., Ltd., London, and British Book Centre, 122 East 55th St., New York 22, N. Y. Beginning with a brief treatment of surveying fundamentals and a discussion of the correlation of surface and underground surveys, this practical manual continues with descriptions of surveying practice both above and below ground including stopes, inclined shafts; etc. Space is devoted to sampling and valuation, geological considerations, and descriptions of modern surveying instruments. The organization of survey operations is covered in the last chapter.

Jan 1, 1952