Search Documents

By R. F. Domagala

SOME of the results of a program designed to study the kinetics of transformation and related mechanical properties of prototype Zr-X binary alloys systematically are presented here. The object of this program was to provide a sound basis for a scientific approach to the realization of optimum properties in binary zirconium alloys. Alloys of Zr-Mo (eutectoid), Zr-Sn (peritectoid), and Zr-Ti (a and ß isomorphous) were prepared and studied. The data herein are confined to a presentation of the results of studying the eutectoid prototype alloys. The Zr-Mo phase diagram has been determined.&apos; A definitive metallographic study of isothermaily annealed samples prepared from high purity elements served to position a sluggish eutectoid reaction, ß?a + ZrMo2, at 780°C. The compositions of the phases involved in this reaction are: ß, 7.5 ±1 pct Mo; a, <0.18 pct Mo; and ZrMo2, 67.8 pct Mo. Inasmuch as a lower purity sponge zirconium was used in this work boundary placements were rein-vestigated with the less pure alloys. Materials and Procedures Hafnium-free sponge zirconium was used to prepare all ingots. The arc melted hardness of a small button of this zirconium was found to be Vpn 168. Chemical analyses conducted at Armour Research Foucdation are shown in Table I, High purity molybdenum sheet was used as the alloy addition. A typical analysis is shown in Table I. Several 200-g Zr-50 pct Mo alloys were made by arc melting. Crushed granules of this material were used to ensure inqot homogeneity Ailoy ingots were prepared by double melting techniques. First, three 5-lb ingots of each alloy composition were are melted in 2 nonconsumable electrode arc furnace. After melting. the ingots were ground to remove surface defects. A subse-

Jan 1, 1958

By Sam F. Carter

FOR some time melters and metallurgists have recognized the fact that steels may be made to identical compositions as ordinarily analyzed, but with considerable variations in physical properties. Good melting practice signifies a combination of furnace operations that will produce steel with consistently good physical properties after proper consideration of cost, production efficiency, and chemical control. In acid practice, these operations may be classified fundamentally as: (I) the oxidizing boil, (2) recarburization and deoxidation, (3) slag adjustment, and (4) final deoxidation. These operations affect the properties of the steel through variations in the minute quantities of several microscopic, submicroscopic, and dissolved constituents, which are out of reach of ordinary analyses but are very influential upon the crystallographic slippage and the molecular cohesion of the structure. One of these constituents is the FeO left in solution in the steel. Herty has shown that steels high in dissolved FeO have decreased ductility and impact and increased hardness and electrical resistance. There is also much evidence that FeO in solution affects carbon solubility and diffusion, and consequently abnormality and carburizing behavior.

Jan 1, 1947

By Wolfram Ruff, H. A. Schwartz

THE spheroidal form of the temper carbon nodules in malleable cast iron and of the graphite mottles of "mottled" cast iron suggests that in both all the graphite in a given mottle or nodule grew from a single center of crystallization or nucleus. ‡ There is, however, a distinct metallographic difference between the mottle and the nodule; the area of mother metal impoverished in combined carbon by the crystallization of graphite in a mottle is practically coextensive with the ramifications of the graphite, while the impoverished zone of metal corresponding to a given nodule is always larger, and usually much larger, than the approximately spherical mass of graphite crystals forming the nodules. Furthermore, the mottle probably is formed during freezing and the nodule almost always at a considerably lower temperature. Assuming that the nodules or mottles can be used as a measure of the existing nuclei (capable of germination) we propose to record certain observations as to the graphitizing reaction in the light of the number and habits of growth of these nuclei. The present authors, in cooperation with others 1-7, have reported upon various cognate aspects of the problem. The fact that temper carbon is a mass of flakes and not a solid granule has become well recognized since the introduction of an improved polishing technique8,9,10 for cast iron. The problem of deriving from the circular planar intercepts

Jan 1, 1935

By J. W. Powell

A Federal statute, enacted several years since, provides for the preparation of a geologic map of the United States. There are three requisites for a geologic map. The first is a suitable base- or surface-map upon which the rock-formations may be platted by means of conventions ; the second is a classification of the rocks and formations, and the third is a system of conventions by which the rocks and formations may be represented on the map. When the work of the Federal bureau created to prepare the geologic map was commenced, a topographic survey of the country was undertaken for the purpose of making maps suitable for the use of geologists in the field and for the representation of the geology; and this work has ever since been continued. The surveys have now extended over about one-fifth of the national domain, and are mapped on a series of atlas-sheets, each constituting a section of the great map of the United States. About 700 of these atlas-sheets are completed. They are in extended use among engineers, miners, prospectors, map-publishers and educators, and are thus widely known; moreover, these base-maps have been exhibited, described and discussed at meetings of the Institute, and thus do not require detailed consideration. Classification of Bocks and Formations. Modern classification is designed to express natural relation. In the beginning of observational science, or natural science, objects were discriminated and grouped by differences and resemblances; but at first the differences and resemblances recognized in the classification were external, even superficia1,&apos;and often confined to single features. Later, groups of features and characteristics, both external and internal, were recognized as the basis of classification ; and of recent years, throughout the entire domain of biology, and to a considerable extent in the kindred sciences, classification is based not

Jan 1, 1893

By William J. Coulter

WITHIN the past thirty years the United States has been involved in two tragic, vicious, and costly world wars. To make the world safe for democracy was the reason given for our participation, but the confusion and misunderstanding that prevails all over the world today suggests that war is not the proper approach to the attainment of that utopia. These conflicts were conceived and prosecuted by nations far advanced in civilization and culture. Their best manhood was sacrificed, a staggering tax burden was saddled on their peoples, huge financial losses were incurred, destruction of property was appalling, and cultural and peaceful scientific advancement received a setback that may require centuries to retrieve. Therefore, some basis is established for the conclusion that progress in the past fifty years has been most outstanding in the development of instruments used for death and destruction, and that progress in this direction between the two World Wars would indicate that the next war will go far toward total destruction of world civilization.

Jan 1, 1946

By E. G. Bailey

The bituminous coal industry faces a real problem, if it desires to retain the position in the power-generation field to which it is economically entitled. More power is probably produced today for electrical energy, for steam-driven and steam-heating industries and processes, for transportation by rail, water, highway and air, collectively, than ever before, and yet the total bituminous coal production has decreased about 38 per cent, from 575,000,000 tons in 1926 to 357,500,000 tons in 1934. It is not the intention of the writer to recommend coal as a fuel for automobiles and airplanes, but rather to point to these forms of transportation as being responsible in a very measurable degree for reducing the coal consumed by railroads. Petroleum products may still further reduce consumption of locomotive fuel through the extension of the use of Diesel-driven trains. Oil-burning steam-driven locomotivcs are replacing coal in some places, where railroads operating high-speed passenger trains are willing, temporarily at least, to pay a premium for the fuel that is low in ash and produces less smoke and practically no cinders. In the navy and ocean-going passenger ships, oil is so firmly established, and has such definite advantages over coal as formerly fired, in steaming radius, in ease of bunkering, cleanliness, and reduction in firing labor, that very outstanding developments in the handling and burning of coal will be rcquired in order to replace oil. For freighters on the Great Lakes, coal is the logical fuel, but there is great and immediate need of radical improvements in its use, else that market also may be lessened. It is not within the scope of this paper to discuss in detail bituminous coal for either locomotive or marine use, but, rather, generation of power in stationary plants, consisting of electrical generating stations and that very large group of miscellaneous industrial plants, such as paper, rubber, textile, steel and other industries that use electrical, mechanical, and steam power, derived from either hydro or some form of fuel.

Jan 1, 1936

By G. W. Bain

The Canadian magnesite deposits are situated in Grenville township, about 8 miles from Calumet station, on the Canadian Pacific Railway, but the poor transportation facilities have hindered their development. Magnesite was discovered in the boulders near White Rock Lake by Rev. W. P. Boshart in 1900. Observing that the material of these boulders was more glistening and whiter in color than Grenville limestone, he sent a specimen to the Department of Mines, Ottawa. An analysis showed this to be almost pure carbonate of magnesia and of commercial value if present in sufficient quantities. That summer, Boshart and McAllister found numerous outcrops, both of boulders and of bed rock, that gave promise of being magnesite of a commercial grade, and decided that this mineral deposit, if developed, would rival that at Veitsch, Austria. So they procured options on most of the land on which they knew the magnesite occurred. But the transportation difficulties were too great for the deposits to be mined at the prices offered for the product. In 1907, T. J. Waters organized the Canadian Magnesite Co. and opened a quarry on the north half of lot 18, range IX, and later on lot 15, range IX, of the same township. A lirnestone kiln was erected and the calcined rock was hauled to Calumet. In 1914, the North American Magensite Co, took over the quarries and shipped both crude and calcined magnesite until January, 1923. During 1915, S. Melkman organized the Scottish Canadian Magnesite Co. and opened a quarry on lot 15, ranges X and XI, Grenville township. A light, narrow-gage railway connects this quarry with the C. P. R. at Magnesite station. but shipments are made only during the summer months. Numerous other quarries have contributed to the output of the district but the greater part has come from the open pits of the

Jan 1, 1923

By E. G. Bailey

The bituminous coal industry faces a real problem, if it desires to retain the position in the power-generation field to which it is economically entitled. More power is probably produced today for electrical energy, for steam-driven and steam-heating industries and processes, for transportation by rail, water, highway and air, collectively, than ever before, and yet the total bituminous coal production has decreased about 38 per cent, from 575,000,000 tons in 1926 to 357,500,000 tons in 1934. It is not the intention of the writer to recommend coal as a fuel for automobiles and airplanes, but rather to point to these forms of transportation as being responsible in a very measurable degree for reducing the coal consumed by railroads. Petroleum products may still further reduce consumption of locomotive fuel through the extension of the use of Diesel-driven trains. Oil-burning steam-driven locomotivcs are replacing coal in some places, where railroads operating high-speed passenger trains are willing, temporarily at least, to pay a premium for the fuel that is low in ash and produces less smoke and practically no cinders. In the navy and ocean-going passenger ships, oil is so firmly established, and has such definite advantages over coal as formerly fired, in steaming radius, in ease of bunkering, cleanliness, and reduction in firing labor, that very outstanding developments in the handling and burning of coal will be rcquired in order to replace oil. For freighters on the Great Lakes, coal is the logical fuel, but there is great and immediate need of radical improvements in its use, else that market also may be lessened. It is not within the scope of this paper to discuss in detail bituminous coal for either locomotive or marine use, but, rather, generation of power in stationary plants, consisting of electrical generating stations and that very large group of miscellaneous industrial plants, such as paper, rubber, textile, steel and other industries that use electrical, mechanical, and steam power, derived from either hydro or some form of fuel.

Jan 1, 1936

By H. E. N. Stone, B. L. Daniell

This paper examines the cracking behavior on chemical reduction of three types of ore/oxide briquette mixtures. The complex sintering/hardening atmosphere was replaced by 100% oxygen and the blast furnace atmosphere by a 5/95 hydrogedsteam mixture which was used isothermally at 700°C for a constant, arbitrary time. Cracking has been assessed by measurement of reduction expansion or increase in specimen diameter as a result of chemical reduction and a subjective index based on appearance and friability. Oxidized briquettes of iron ore concentrate crack on reduction&apos;-3 in a manner which parallels the degradation of sinter in the Linder test. In the present work, the cracking behavior on chemical reduction of three types of ore/oxide briquette mixture has been studied. Firstly, LD converter fume with additions of silica; secondly, Oxfordshire ore with ferric oxide; thirdly, ferric oxide with separate additions of silica, alumina and lime. Motivation for the first-mentioned experiments lay in the improvement of the fume as furnace feed; for the second, in assessing the tolerance of a finely divided ferric oxide as a base for low melting point additions. The third series provided additional information. In this work, the complex sintering/hardening atmosphere is replaced by 100% oxygen and the blast furnace atmosphere is replaced by a 5/95 hydrogen/ steam mixture used isothermally at 700°C for a constant arbitrary time. The particular reduction conditions were known from previous experience3 to be capable of disclosing any tendency to cracking. Cracking has been assessed by measurement of reduction expansion (i.e., increases in specimen diameter as a result of chemical reduction) and a subjective index based on appearance and friability. Generally

Jan 1, 1970

By G. W. Bain

The Canadian magnesite deposits are situated in Grenville township, about 8 miles from Calumet station, on the Canadian Pacific Railway, but the poor transportation facilities have hindered their development. Magnesite was discovered in the boulders near White Rock Lake by Rev. W. P. Boshart in 1900. Observing that the material of these boulders was more glistening and whiter in color than Grenville limestone, he sent a specimen to the Department of Mines, Ottawa. An analysis showed this to be almost pure carbonate of magnesia and of commercial value if present in sufficient quantities. That summer, Boshart and McAllister found numerous outcrops, both of boulders and of bed rock, that gave promise of being magnesite of a commercial grade, and decided that this mineral deposit, if developed, would rival that at Veitsch, Austria. So they procured options on most of the land on which they knew the magnesite occurred. But the transportation difficulties were too great for the deposits to be mined at the prices offered for the product. In 1907, T. J. Waters organized the Canadian Magnesite Co. and opened a quarry on the north half of lot 18, range IX, and later on lot 15, range IX, of the same township. A lirnestone kiln was erected and the calcined rock was hauled to Calumet. In 1914, the North American Magensite Co, took over the quarries and shipped both crude and calcined magnesite until January, 1923. During 1915, S. Melkman organized the Scottish Canadian Magnesite Co. and opened a quarry on lot 15, ranges X and XI, Grenville township. A light, narrow-gage railway connects this quarry with the C. P. R. at Magnesite station. but shipments are made only during the summer months. Numerous other quarries have contributed to the output of the district but the greater part has come from the open pits of the

Jan 1, 1923

By V. H. Gottschalk

SEVERAL years ago a group in the metallurgical division of the U. S. Bureau of Mines began a study of the application of new developments in physics to metallurgical problems&apos;. Among these developments were the extensions of what may be termed by analogy the "sound spectrum." Electromagnetic waves, from X-rays to radio waves, have been quite thoroughly explored for metallurgical use, but the sound spectrum, extending from low-frequency vibrations involved in certain types of metal failure by fatigue through the range of audible sound to inaudible vibrations having frequencies of many kilocycles, has had only meager consideration from metallurgists. Because of the general interest in the process recently demonstrated by St. Clair3 for flocculating smoke by means of sound waves, this article is written to point out possible applications of sound and supersonic (ultrasonic) waves in the metallurgical industry.

Jan 1, 1937

By J. B. Wagstaff

The raceway in front of the tuyere of the blast furnace has been studied quantitatively and a correlation obtained for the penetrastudiedtion of the blast. Some evidence is presented for the height and width of the raceway which suggests that all the raceways of a ffurnace overlap. The size of the coke in this zone has been measfurnaceoverlap.ured photographically during normal operation and results are given for the various areas. IN an earlier paper,&apos; it was shown that a raceway exists opposite each tuyere of a blast furnace. This raceway is formed by the jet effect of the air emerging from the tuyere and consists essentially of a turbulence in which coke particles are recir-culated at high speed. Its presence was deduced originally from observations on movies taken with a high-speed camera through the tuyeres of various furnaces and was confirmed by experiments made on a model. In the model described,&apos; this raceway was shown as operating in a vertical plane only, although there was a suggestion in the motion-picture film exhibited at that time that the raceway was three dimensional, unless artificially restricted. There was also some doubt then about the factors influencing its size. This paper describes the next steps in the investigation. Since the size of the raceway is obviously of importance in the operation of the furnace, it seemed worth while to study the subject more carefully. It is probably in this region that about half the coke in the furnace is consumed, so that the movement of the stock column may well be controlled by raceway behavior. Furthermore, there is some evidence to suggest that the coke is packed densely in the center of the furnace to form the "dead man" and more loosely above the raceway. It is therefore probable that the bulk of the gases passing up the stack flow from the top surface of this raceway. Clearly then, a knowledge of this critical zone is of interest to the blast furnace operator, and the first half of this report is devoted to a quantitative discussion of the subject. A further topic of interest among operators is the degree of breakdown of coke in the furnace, with which is inseparably linked the importance of a strong coke. Indeed, the whole question of the optimum size and type of coke may be as dependent on the condition of the coke in the bottom of the blast furnace as at the top. Attempts have been made from time to time to obtain samples of coke from the tuyeres and other furnace openings but they all suffer from the fact that the coke is filled to a varying degree with metal and slag and is probably broken up by the very act of taking the sample. It has proved difficult to make any reliable studies of coke size by these methods. However, it did seem possible to use the highspeed movies mentioned earlier1 to estimate the size of the coke. These movies provide an accurate record of individual coke particles so that, in theory at least, it should be possible to measure the size of the particles one by one and to obtain, for the first time, information on the coke being blown around the raceway under actual operating conditions while the furnace is performing normally. Such a study has been made and is discussed in the second half of this paper. The results obtained enabled the blast furnace data to be correlated with the model results given in the first half. Raceway Size In order to make a quantitative study of the size of the raceway it was necessary to devise some apparatus of laboratory scale, which could be handled quickly and easily. This focused attention on models, which in turn means that the laws of similarity governing this particular process must be ascertained. Method of Procedure: Since the work was to be carried out on a smaller scale than the blast furnace, the linear dimensions of the model became unimportant provided that the scale was known; it is only important to insure that the container does not affect the raceway being observed. The studies therefore were carried out in a glass-sided box, 11 in. high x 7 in. wide x 3 in. deep, using air jets ranging

Jan 1, 1954

By C. W. Beattie, R. L. Solter

ALUMINUM-KILLED, low carbon steel sheets are used extensively for severe deep drawing and other difficult forming operations. They usually, but not always, have a characteristic grain structure in which the grains are elongated both in the lengthwise and in the transverse direction. As described by Burns and McCabe,&apos; a typical grain in the plane of the sheet has its two axes in that plane from 1 Y2 to 4 times as long as the axis normal to the plane of the sheet. Rickett, Kalin, and MacKenzieZ have also reported on the recrystallization behavior of such steel. The contrast in grain structures of fully processed sheets of aluminum-killed and rimmed steel is illustrated by Figs. 1 and 2. The elongated grain structure of the aluminum-killed sheet is not developed on all heats or lots of this metal, and studies of the factors controlling and influencing its formation are reported in this paper. Jeffries and Archerb tate that unstrained grains are normally equiaxed, but exceptions are common. For example, if a metal containing a material mechanically obstructing grain growth is subjected to considerable working followed by thorough annealing, it may exhibit grains consistently elongated in the direction of working. Our experiments demonstrate that aluminum-killed, low carbon steel is such a metal, and that the substance mechanically obstructing grain growth is aluminum nitride. The effectiveness of aluminum nitride in inhibiting grain growth has been found to be influenced by the degree of cold reduction, the rate of heating in annealing, the thermal history of the sample before cold reduction, and the residual aluminum content. A correlation between grain shape and austenitic grain coarsening temperature also was indicated and additional experiments demonstrated that aluminum nitride is also the principal cause for the fine grain characteristic of aluminum-killed steels. Manufacture In conventional practice, aluminum-killed sheet steel is manufactured from a low carbon steel containing approximately 0.02 to 0.07 pct residual (HC1 soluble) Al. With the exception of certain samples containing greater or lesser amounts of aluminum, the steels used in these investigations were within the following composition range: C, 0.03 to 0.06 pct; Mn, 0.28 to 0.38; S, 0.017 to 0.032; Al, 0.03 to 0.06; P, <0.01; and Si, <0.01. Properly heated ingots are rolled to slabs about 4 in. thick. After surface conditioning, the slabs are reheated to about 2300°F and hot rolled continuouslv to strip about 1/10 in. thick. The strip rolling is completed at a temperature of 1550°F or higher, and the strip is coiled, usually at a temperature near the lower critical transformation. After cooling, the strip is pickled to remove oxide, cold reduced 40 to 70 pet to final thickness, then annealed to 1250° to 1350°F in 20 to 80 ton charges, the size of which results in slow heating and cooling rates. Effect of Cold Reduction According to Sachs and Van Horn,&apos; the deformations of the individual grains in rolling are similar to those of the total volume. Thus individual grains would elongate in rolling according to the amount of cold reduction imposed. This is true theoretically, but as cold reduction increases the individual grains tend to fragment, and measured grain elongations become less than theoretical. The amount of grain elongation may be described by a numerical rating based on grain counts made by the intercept method. Specimens are polished normal to the plane of the sheet, with the polished surface extending parallel to the rolling direction. After etching, grain intercepts are counted along a 50 mm line on a micrograph of suitable magnification. In random locations parallel to the plane of the sample 20 counts are made and 20 are made in the thickness direction of the sample the average count in the thickness direction divided by the average count parallel to the plane of the sample gives a numerical rating of the grain shape called grain elongation. For example, a grain elongation of 2.00 means that the average grain is twice as long as it is thick. The average of both counts may be converted to grains per sq mm by a nomograph relating intercept counts and grain count. By the same procedure the grain elongation in the plane of the sheet but transverse to the rolling direction may be determined, using transverse metallographic samples. A comparison of theoretical and measured grain elongation was obtained on an aluminum-killed

Jan 1, 1952

By Robert Linton

In 1898, Joseph L. Giroux and J. A. Snedaker organized the Pilot Knob Copper Co. and began developing the Pilot Knob mine at Kim-berly, Nev., for high-grade copper ores, carrying good gold and silver values, that the formation had disclosed. At that time the nearest railroad was over 150 mi. distant. The high-grade ores did not prove to be extensive at this point—at least to the depth (240 ft.) to which the work was carried—but development of neighboring claims indicated extensive deposits of sulfide porphyry ore of concentrating grade lying at shallow depth, and deeper deposits of direct-smelting oxidized ores occurring in limestone near the limestone-porphyry contact. The properties passed through the hands of several organizations, with only meager development, until acquired in 1913 by Consolidated Coppermines Co., whose holdings now comprise 3480 acres of mining claims in the Robinson district. Since that time development has been prosecuted more actively; and for the purpose of determining the most efficient and economical method of treating the ores, considerable testing work has been done during the past three years, both in the laboratory and in actual mill operations. At first, the shipments were of ore high enough in grade to be profitable even with the long wagon hauls to the railroad and prevailing freight and smelting charges. In 1905, a blast furnace and a concentrator were erected at Kimberly. On account of insufficient ore supply, the blast furnace was never blown in and later was dismantled. The concentrator as originally equipped was operated for only about two months, both because the ore supply at that time was not sufficient and because gravity concentration did not yield satisfactory extraction. The location and arrangement of the mill further entailed high operating costs. In 1908, the Nevada Consolidated Copper Co. began to mill successfully, on a large scale, its sulfide porphyry ores, which are similar in character to the adjacent Coppermines ores. After that time, all of the ores and concentrates produced by Coppermines Company were smelted and a considerable part of the Coppermines low-grade ores concentrated at the Steptoe works of the Nevada Consolidated Co.

Jan 1, 1921

By John D. Meahin

THE use of digital methods for generating crystallo-graphic data is well-established and many programs are now available. Transmission electron microscopy usually requires a knowledge of the electron diffraction pattern which is obtained by plotting a planar section through reciprocal space. With cubic symmetry these sections are very easily produced, but with hexagonal and lower symmetry systems considerably more labor is involved. Johari and Buchanan1 have written a Fortran program for generating standard projections and along similar lines we have produced a short but completely general program for generating any section through reciprocal space. The required inputs are the lattice parameters and angles for the real crystal. The Miller indices of the direction [U, V, W] parallel to the electron beam are then specified and the program will generate the Miller indices of the plane normals perpendicular to [U, V,, W] up to some specified integer. A subroutine can be inserted to test for forbidden reflections if desired. We have used such routines for fct and hcp crystals. As each permitted index is generated it is printed or punched out and no storage arrays are utilized in the computer. The normal diffraction pattern corresponds to the zero-order Laue zone, but with thin crystals or crystals of large lattice parameters the higher-order Laue zones may contribute to the diffraction pattern. Accordingly the program will generate successive Laue zones and project them onto the zero-order zone. The output of the program first lists the zone axis [C, V, W] and the Laue zone, and then gives a list of permitted reflections and the corresponding XP and YP coordinates of the reciprocal lattice point in angstroms-&apos;. In addition, ZP, the perpendicular distance of the reciprocal lattice point from the (U, V, Ur) plane in reciprocal space is given, as is the reciprocal interplanar spacing. In the case of the zero-order Laue zone ZP is zero. A diffraction spot from the higher-order Laue zones will be very slightly displaced from the computed coordinates as its position in an actual pattern is given by projection along the diffracted beam2 and not along [u, V, w]. For any given electron wavelength this correction could be readily incorporated into the program, but as it only amounts to -1 pct it was decided to leave the program in its most general form, i.e ., a computation of points

Jan 1, 1970

By Schlumberger, C

IN the search for practical geological problems amenable to solution by the potential methods, the geophysicist is led to study mathematically various theoretical cases. In these idealistic discussions, the media under consideration are generally supposed to be homogeneous and iso-tropic. The geophysicist, of course, realizes perfectly that these condi-tions do not occur in their entirety in reality. However, the assumptions made are justified, because very often they are necessary in order to render possible an exhaustive study of a given problem, which otherwise would be too complicated, and would not lend itself to a complete mathe-matical analysis. Of the above two assumptions, that concerning the homogeneity of a given geological formation is satisfactorily realized except in so far as isotropy is concerned, since this property is not often encountered in practice. As a consequence, it is very desirable for the geophysicist to have quite an extensive knowledge of the properties of anisotropic forma-tions, and of the laws that govern the propagation of electric current therein. With such principles in mind, he will be able to decide whether the conclusions arrived at in simple, isotropic conditions are still correct in more complex cases, or in what way they must be modified or adapted in order to constitute a sound basis for the interpretation of the results obtained in anisotropic media. On the other hand, the fact that in anisotropic formations themobility of the ions is greater along the strike than perpendicular thereto can be utilized for determining the direction of the dip by induc-tion measurements. We therefore propose to study in three successive chapters the following points: 1. Propagation of the electric current in anisotropic media. 2. Some consequences of the anisotropy of geological formations with reference to the surface electrical measurements, and their interpretation. 3. Determination of the direction of the dip of anisotropic formations by surface induction measurements.

Jan 1, 1933

By R. W. Waterfill

MANY existing ore deposits of valuable metals have been worked out in their upper surface levels and the continued productivity of these mines is dependent on their extension to greater depths in the earth. The maximum depths at present reached are about 6000 to 8000 ft. below the surface, with no evidence of an impoverished ore vein. These mines are widely distributed; some of the best known are in South Africa, Brazil, India and in the western sections of the United States. Among the factors which increase the difficulty of working these mines at increasing depths are hoisting, rock pressure and temperature. The manner and effectiveness with which these problems are met will, no doubt, determine in a large measure the ultimate depths to which any mine can be profitably worked. The most critical of these three factors at present is the increase in temperature with depth. The high temperature and humidity in many of these mines at present is severely detrimental to the health of the workers and greatly hampers their efficiency. Some have almost reached a condition in which the human system cannot survive. The problems involved in the cooling and ventilation of mines have all been ably analyzed and presented in previous articles. For this reason, only a resume of conditions affecting the cooling and conditioning of deep and hot mines will be given in this paper before attention is directed to possible methods of improving atmospheric conditions in the working levels.

Jan 1, 1929

By C Gunther

In the examination of an undeveloped prospect a decision must be arrived at from an inspection of the outcrops and the exposures in a few shallow pits. Prospects that are offered for sale rarely expose any important quantity of good ore, work having usually been stopped when the immediate exploration no longer yielded favorable results. It should be borne in mind, furthermore, that a great majority of prospects have been examined many times, and if of conspicuous promise, would have been acquired for development. In most cases the problem for the engineer, therefore, is to discover the traces of a valuable mineralization that has disappeared through solution, or the conditions that indicate the possibility, or probability, of underlying secondary enrichments. The available data being meager, every feature should be the subject of careful study-the condition of the outcrop, the structural relationships, the associations of minerals, the alterations of wall rocks, the chances for underlying enrichments, and so forth, as well as the actual assay value of the material exposed. It is frequently advisable to spend the time and money necessary to have trenches dug at various significant points along a promising outcrop; such exposures, even if the depth attained is slight, often disclose conditions that are not apparent at the actual surface, as for example, the existence of soft minerals and the distribution of the various minerals through the mass of the deposit. Trenches also permit samples to be taken from points that were not accessible during former examinations. Strong, persistent outcrops of uniform width may be taken to indicate the probable size and character of the underlying vein,

Jan 1, 1932

By Bradley Stoughton

My attention was called by Prof. Henry M. Howe to the article by N. M. Wittorff, entitled Preliminary Investigation of Primary Crystallization and Subsequent Physico-Chemical Permutations in Iron-Carbon Alloys Containing More Than 4 Per Cent. of Carbon. I thereupon wrote to Mr. Wittorff and received a copy of the paper in the Russian language, with permission from him to publish a translated abstract in our Transactions, the original having appeared in the .Journal of the Russian Chemical Society, vol. xliii. (1911), in which it occupies some 78 pages, with 10 illustrations and 47 micrographs. The novelty of the data presented, and especially the scientific importance of Mr. Wittorff&apos;s deductions, as well as their value in helping to clarify our meager understanding of that useful but puzzling commodity, cast-iron, seemed to more than justify a publication of the essential facts in concise form in the English language, which has not been done previously so far as I know, although a very brief abstract has been published in German, and a somewhat more extended one in French.&apos; When the work of translation was begun, I did not know that it bore in part upon the investigations of Ruff, which Howe is reviewing at some length at this meeting. This coincidence renders the following condensed translation of Wittorff&apos;s work, which I have prepared with the aid of Sidney Marcus as interpreter, the more appropriate here. The result of Wittorff&apos;s study is greatly to extend our knowledge of the hyper-eutectic alloys of iron and carbon, and to add several significant lines at the right-hand side of the diagram originally drawn by Bakhuis-Roozeboom, and developed by Roberts-Austen, Benedicks, Carpenter and Keeling, Upton, Goerens, and others. Some of the original lines of the dia-

Jan 1, 1913

By John B. Porter

Within the last year or so, a great deal has been heard about Southern iron ; even the Eastern markets have felt the effect of the cheap Alabama ores and coals, and public attention has again been drawn to what is now getting to be an old story—the great mineral wealth of the South. The following paper is based on a report prepared several years ago for a special purpose; but since then, through association with Mr. C. B. Going in a large analytical practice and as chemists to the Queen and Crescent Railway, I have had opportunity to increase my material so greatly that the present paper is really a completely different work. I am under very great obligation to Mr. Going, without whose assistance my work would have been very incomplete, and have also been materially assisted by Mr. F. P. Dewey, of Washington, and a host of gentlemen connected with the railroads and furnaces of the South. The arrangement of this paper is not all that could be desired. Some localities of importance are very poorly represented, both in the description and the tables of analyses. This, however, was in most instances unavoidable, as the study has been done ill the intervals of professional work. I have visited almost all the localities described, and, in all cases possible, have taken my own samples, and have made careful per-

Jan 1, 1887