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(Members are urged to send in for this. column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at the Institute headquarters during the period Sept. 10, 1916 to Oct. 10, 1916. Arthur K. Adams, Chanaral, Chile. C. F. Moore, Salt Lake City, Utah. Hiram W. Belnap, Washington, D. C. L. D. Moore, Providence, R. I. E. A. Bridgman, Seattle, Wash. George A. Morrison, Chicago, Ill. D. W. Buckly, Wallace, Idaho. Pablo Ortega, Havana, Cuba. G. L. Carlisle, Jr., New York, N. Y. L. W. Paige, New York, N. Y. Ernest H. A. Cohen, Johannesburg, So. Africa. Charles Petzel, New York N. Y. A. Faison Dixon, Camp Rio de Oro, Venezuela. C. A. Pierce, Patagonia, Arizona. Charles E. Dutton, Goldfield, Nev. W. E. Pomeroy, El Paso, Texas. D.-F. Hewitt, Washington, D. C. George S. Rice, Washington, D. C. . James E. Howard, Washington, D. C. G. J. Schofield, Seattle, Wash. A. 0. Ihlseng, Joplin, Mo. Warren D. Thompson, New York, N. Y. I. Ishikawa, Niagara Falls, N. Y. M. M. Valerius, Tulsa; Okla. Montrose L. Lee, New York, N. Y. G. B. Waterhouse, Buffalo, N. Y. V. H. McNutt, Billings, Mont. Joel H. Watkins Washington, D. C. Benjamin L. Miller, So. Bethlehem, Pa. H. P. Wherry, Chicago, Ill. Arthur K. Adams has left for Chile, where he will act as geologist for the Andes Copper Co., a subsidiary of the Anaconda copper company.

Jan 10, 1916

By Thos. W. Gibson

The object of taxation is the raising of a revenue. Unless a tax accomplishes this, it is a failure. The right to take for public purposes a part of the moneys obtained from the carrying on of private enterprises is an attribute possessed only by a lawful government, and may indeed be called the supreme attribute of government. In free, democratic communities this power must of necessity rest upon the consent of the governed. Power implies obligation, hence it is obviously the duty of a government, in framing a system of taxation, to provide one which, while effective in producing a revenue, is also just and impartial. • It will be conceded that mines and mining property ought to bear a fair share of the public expenditure. The question is, upon what basis taxation should proceed. Two separate taxing principles are usually contended for: Taxation should be proportionate to the benefits received by the person or property taxed; taxation should be based on ability to pay. A third is sometimes added, taxation should have reference to the extent and value of the natural resources enjoyed. As applied to mining taxation, it is pointed out by those who support the fist mentioned basis that, mines being usually situated in rocky and hence sparsely peopled regions, mining companies are frequently obliged to construct roads, railways, telegraph and telephone lines, schools, water and sewerage systems, and many other amenities and conveniencea of civilization the cost of which in regions better suited for agriculture, and consequently more thickly populated, has either been defrayed locally, or can be spread over a sufficiently large taxable group of people to materially lighten the financial burden on the mine. The mining company, it is argued, having made these outlays, should receive credit for them and be relieved of taxation to a corresponding extent. There may be some force in this contention, but the situation is capable of relief without attempting to place taxation upon so unworkable a basis as the value of benefits received. Who is to be the judge of these benefits, and how are they to be valued? The very existence of a mining company and its ability to carry on business in peace and security depeind on the prevalence of law and order, which is a result of good government. The state provides protection against violence, and courts of law for

Jan 1, 1920

By J. H. Swisher

An experimental study has been made of the possible mechanisms for foam stability in the system CaO-SiO2-Cr2O3, where Cr2O3is the foaming agent. The degree of lowering of surface tension by Cr2O3 was determined at 1600 "C for high -silica melts. Measurements were also made of foam stability under standardized conditions. The results of the two sets of measurements then were correlated by applying the Gibbs and Marangoni theories of film elasticity. It was demonstrated that the Marangoni elasticity effect is probably the largest single contributor to foam stability, although the high uiscosity of' silicate melts makes some contribution in controlling the rate of drainage of liquid from bubble lamellae. ThE tendency of metallurgical slags to foam has frequently been observed during steel-refining operations. In the open-hearth furnace,this tendency is considered undesirable because it slows down the rate of heat transfer from the burners to the molten-metal bath. On the other hand, it is sometimes desirable to have a "foamy" slag in the basic oxygen converter.' A more effective blanket over the steel bath is made by a "foamy" slag, and loss in yield of metal due to splashing is minimized. In addition, a flush slag can be removed more easily in this condition. Since slag-foaming problems in the field have been attacked largely on an empirical basis, it appeared desirable to obtain a better basic understanding of the mechanism of foam stability. The experimental work was directed almost entirely toward the behavior of Cr2O3 as the foaming agent in CaO-SiO,-Cr2O3 melts. In the first stage of the investigation, the degree of lowering of surface tension by Cr2O3 was determined at 1600°C. The second stage consisted of measuring foam stabilities under standardized conditions. The two sets of experimental results then were correlated by applying various theories of foam stability. For convenience in interpreting the surface-tension and foam-stability results reported here, a portion of the CaO-SiO2-Cr2O3 phase diagram2 is reproduced in Fig. 1. EXPERIMENTAL 1) Surface-Tension Measurements. Very little information is available in the literature on the lowering of surface tension of slags by foaming agents. Kozakevitch 3 mentioned that the addition of 1.5 pct Cr2O3 lowered the surface tension of FeO slightly. In another system, some data on the lowering of surface tension of foaming slags by P2O5 were reported by Cooper and Kitchener.4 The technique used for the surface-tension measurements was the maximum bubble-pressure method,' using a single tube immersed to various depths in the melt. This method has been used extensively in high-temperature systems, such as in liquid metals, slags, and glasses.6,7 It has the advantage that the contact angle between the liquid and the tube material need not be known. The equation used for calculating surface-tension values from maximum bubble-pressure measurements is the Schroedinger equatioq5 which can be written as follows:

Jan 1, 1964

By J. M. Kane

IN all probability the mining and metallurgical industry as a whole can demonstrate a larger economic return from installation of dust-control equipment than any other major industrial group. This fact has partially accounted for the marked increase of dust-control installations made during the past decade. While the primary objectives for installation of dust-collecting systems are improved working and operating conditions for men and equipment, the fact that an economic return can be anticipated on salvageable materials is an added advantage which shows in partial or complete equipment write-off. The conditions apply to most phases of the mining, milling, and smelting industry, both non-metallic and metallic.

Jan 1, 1953

By R. G. Davies, R. H. Richman

Several techniques, X-ray diffraction, transmission electron microscopy, conventional, metallography, and mechanical property measurements are combined to investigate decomposition in the suPersaturated solid solution Fe-27 at. pct Be. The following sequence of structures for aging temperatures below 400°C is established: massive short-range order, pseudo-FeBe (L2o) order, Fe3Be (DU3) order, sinusoidal modulation of composition, general or continuous precipitation, and discontinuous or cellular precipitation. In addition to this sequence itself, several features of the individual stages are noteworthy; for example, when coherent modulations occur, their development is parallel to (100) everywhere in the specimen apparently without incubation, and both the wavelength and the composition amplitude of the modulations increase with aging time. Two types of discontinuous reaction are observed, depending upon the aging temperature. At low temperatures (<550°C) the boundary-nucleated variety of discontinuous precipitate predominates; but at higher temperatures (>600°C) the crystallographic variety occurs instead. Hardness and flow-stress measurements clearly reflect the quoted structure sequence. Some qualitative aspects of the structure changes and of the relationship between mechanical properties and structure are discussed. BERYLLIUM in solid solution markedly strengthens iron.&apos;" A recent study demonstrated that not only were supersaturated single crystals of Fe-27 at. pct Be very strong, but they deformed primarily by mechanical twinning.3 Such behavior, coupled with the decrease in solid solubility of beryllium in a Fe from about 33 at. pct at 1165°C to about 10 at. pct at 500°C4 as shown in Fig. 1, leads naturally to questions about property changes with aging in this system. In 1929 roll,1 and later Seljesater and Rogers,5 reported that useful increases in strength could be obtained by aging quenched Fe-Be alloys, but it was not until quite recently that any of the details of precipitation in these alloys were studied. Richman6 observed that both an Fe3Be superlattice (with a DO3 crystal structure the same as Fe3A1, illustrated in Fig. 2) and a modulated structure preceded the appearance of a discrete second phase in the 20 at. pct Be composition. Here, a modulated structure refers to a periodic composition fluctuation within one crystal, while its lattice remains coherent. Subsequent work on a Fe-Be alloys by Heubner7 and von Heimendahl and Heubner8 confirmed the existence of the modulated structure, although only an FeBe (L20) ordered structure was detected (also shown in Fig. 2). Both Rich-man and Heubner corroborated the large increases in hardness during aging reported earlier, but other mechanical properties were not examined. Since modulated systems are encountered relatively infrequently, the influence of coherent modulation upon mechanical properties is not well-known. With the accumulation of information about age-hardening systems, it has become clear that many precipitation reactions cannot always be described by the concept of heterogeneous nucleation at some lattice discontinuity followed by diffusional growth. Rather, complex sequences involving prior "preparation" of the matrix are quite common; that is, a transition structure occurs in the parent phase, instead of in some "nucleus" form. Delineation of such subtle sequences appears to be a worthwhile step toward the understanding of solid-state precipitation. Since not many structural progressions of comparable nature have been reported, the objectives of the present survey are to identify and elucidate the various

Jan 1, 1967

By V. M. Dobrynin

Experimental data demonstrate that physical properties of porous rocks change under pressure. In this paper an assumption is made and proved that under pressure the changes of physical properties such as porosity, density, permeability, resistivity and velocity of elastic waves are controlled to a large extent by the pore compressibility of rocks. It is also shown that the pore compressibility of rocks can be determined, within the range of pressures from 0 to 20,000 psi, by knowing the maximum pore compressibility and the magnitude of the pressure. Mathematical equations were developed which permit one to define changes in physical properties of porous rocks under pressure. These equations were verified by experimental data obtained from the study of sandstones. INTRODUCTION In studying the behavior of porous rocks under pressure in the field of petroleum technology, the most interesting aspect is the observation of those properties which characterize the rocks as possible reservoirs — for example, porosity, permeability, resistivity, density and the velocity of elastic waves. The literature dealing with this problem mainly contains data concerning the study of only one or at most two of these parameters, but not of the group as a whole. An attempt is made in this paper to find general equations involving each of these parameters, which will permit the study of the behavior of rocks under pressure. All experimental data used here were obtained from the investigation of consolidated sandstones. EXPERIMENTAL In addition to the use of published experimental data, an experiment was carried out which studied the main physical properties of sandstones under pressure. Two homogeneous quartz sandstones were chosen for this purpose: (1) the Torpedo sandstone from Kansas, and (2) the Medina sandstone from Ohio. The porosity of the Torpedo sandstone was 20.2 per cent, and that of the Medina 8.7 per cent. Permeabilities were 45 md and less than 1 md, respectively. Each sandstone contained about 5 per cent clay minerals, consisting mostly of kaolinite and chlorite, which were distributed quite evenly throughout the samples. One cylindrical sample 2 in. in diameter and 5 in. in length was cut from each sandstone and then saturated in a vacuum with a 3N solution of NaC1. This high concentration was used in order to obtain true formation factors and to decrease the swelling of the clay minerals. The methods of mounting the samples and measuring the changes in porosity and resistivity were practically the same as those described by Fatt and Mann.1,2 Changes of resistivity under pressure were studied for sandstones with 100 per cent water saturation, and for sandstones with the irreducible water saturation. The irreducible saturation was obtained by enclosing the saturated rock samples in relatively fine silicate powder so as to remove the water by capillary action. This procedure is described by Orkin and Kuchinski.3 Changes of permeability with pressure were determined at room temperature using nitrogen as the flowing medium. In studying the effects of pressure, one series of measurements was made using an internal pore pressure Pi equal to the atmospheric pressure, while the overburden pressure Pe ranged from 0 to 20,000 psi. A second series of measurements was used over the same range of overburden pressure, but with an internal pore pressure of 1,800 psi. When the results were compared on the basis of net overburden pressure (Pe — 0.85 Pi ), there was practically no difference for these two sandstones. The origin of the factor 0.85 in the expression for net overburden pressure is given by Brandt,4 Fatt5 and Geertsma.6 The relatively large bulk volumes of the sample (about 15 cu in.) made it possible to observe a

By Franklyn Oatman

IN order that the conditions which obtain in an oil well may be readily understood, a brief description of a typical California well and. a number of the phenomena accompanying same will be given. That the necessity for the exclusion of water be realized, the effects of water intrusion, a description of methods of prevention, and a discussion of causes of failure will be presented, followed by a summary and recommendations. Fig. 1 shows a section of a typical well which illustrates the relation of oil sands to overlying strata. It indicates a deep water sand separated from the oil sand by shale, and the proper place for the final shutting off of water. In this well a comparatively thick stratum of compact shale protected the oil from overlying water so that the operation of landing the water string was a simple matter. In some wells the protecting stratum may be only from 3 to 5 ft. thick and very careful operation is necessary in order to land the water string of casing properly and not puncture through to the oil sand. The cases just cited are common, but occasionally, after excluding overlying water, productive oil sands are drilled through in the expectation of finding more productive underlying sand, and a water-bearing stratum is tapped. In this case the problem is the reverse of the normal; water must be prevented from ascending rather than descending. A discussion of well-drilling methods is not within the scope of this paper, except such operations as pertain to shutting off of water. A brief outline of the several conditions which may accompany drilling follows. Some or all may be present in any particular case. The direct relation of these to prevention of intrusion will he discussed in detail further on. In drilling, the hole. becomes more or less irregular in shape, and rough, and as the casing follows the bit into the well it does not fit snugly against the walls. As a result, water may descend between the casing and walls of the well. If a circulation pump is not used during drilling, the hole is simply punched through and the pulverized material removed from the well by means of a bailer. If circulation is maintained there is a continual flow of water down inside the casing and up around the outside between the pipe and the walls of hole. This keeps an open. space around the pipe.

Jan 3, 1914

By Anson Hayes, John Chipman

The quality of sheet and strip products made of rimming steel is closely related to the structure and chemistry of the ingots. The variation in composition throughout the ingot, as affected by segregation, is of great importance, as are also the form and distribution of the voids that result from the gases evolved. It is because of this importance that the considerable literature in this field has accumulated. No attempt is made in the present paper to compile a bibliography of the excellent work that has already been done, as this has been adequately covered in the many excellent reports on the heterogeneity of steel ingots prepared by a joint committee and published by the Iron and Steel Institute.&apos; From time to time, in any field of investigation new tools and new technique are developed, which make further progress possible. In the field with which this paper is concerned, this is true. The development of the vacuum-fusion method as a means of following oxygen segregation, and a technique for obtaining the volume and composition of the gases evolved during solidification, have opened the way to obtaining data by means of which some considerable progress has been realized in developing more of the detailed mechanisms of solidification and segregation in rimming-steel ingots. General Theory of Segregation The basic cause of segregation lies in the fact that the impurities are less soluble in solid than in liquid iron. The solid that forms from the impure liquid is more nearly pure than the liquid itself. If solidification proceeds slowly enough, or if the liquid and solid phases are maintained in contact with one another for a sufficient time, a condition of equilibrium is set up, which may be represented by a phase diagram. Portions of the

Jan 1, 1939

By Sir John Cadman

Since my previous review of the Persian fields, presented in 1929,&apos; considerable progress has been made. The main feature of drilling development has been the delimitation of the Haft Kel field and its extensions. Although the limits have not yet been reached, a productive area of about 40 square miles has already been proved and it is now certain that the field will be of the same order of importance as the Masjid-i-Sulaiman field. Production to main pipe line from Haft Kel was begun in November, 1929, and to date about 4,500,000 tons have been produced. Normal production has continued from the Masjid-i-Sulaiman and Naft Khaneh fields. The search for oil in horizons below the main producing limestone is perhaps the most interesting and important exploratory drilling work in progress. Promising results have been obtained in the first well deepened in the Masjid-i-Sulaiman field with this objective, and the exploration of these lower formations is being continued. In this connection an allied program of geochemical research work on the nature of the oils and oil-bearing rocks of different horizons is at, present being undertaken. Masjid-i-Sulaiman Field Since the Haft Kel field was brought into production in 1929, production from Masjid-i-Sulaiman has been reduced in order to equalize to some extent the producing lives of the two fields. The production for the last four years has been as follows: m Approximate Equivalent in TonB Barrels 1929 5,434,071 38,038,497 1930 4,925,869 34,481,083 1931 4,248,086 29,736,602 1932 Approximately 4,500,000 31,500,000

Jan 1, 1933

By L. A. Roe

Magnetic separation of iron ores is one of the fastest-growing segments of the minerals beneficiation industry. The tonnage of taconite ores processed annually by magnetic separation will, in a few years, reach 100 million. Magnetic separation occupies an attractive position in the field of ore beneficiation. It is a simple yet effective method, used for some 150 years and steadily growing more important. This type of beneficiation orginated in 1792, when William Ful-larton was issued a British patent covering the separation of iron ore by magnetic attraction. What is magnetism, and why are some materials capable of being magnetized and others not The study involves many unknowns, and even a partial answer to these questions would be a dissertation in solid state physics and perhaps other fields of science. But the last two decades have revealed basic facts as to why certain materials are magnetic and what happens to them when they are magnetized. Some of the newer studies in solid state physics have developed a theory that can be applied to studies of magnetism. It is claimed that magnetism stems fundamentally from the spin of electrons in atoms that tend to go in pairs, spinning in opposite directions. The atom as a whole can act as a magnet only when there is an imbalance of electronic spin. Whenever an atom has an odd number of electrons, therefore, this imbalance exists. This neutralizing effect explains why a piece of material that contains atomic magnets is not necessarily magnetic. The physicists tell us that iron is composed of many small magnetized regions called domains, which consist individually of millions of atoms. The piece of iron becomes magnetized when an external force lines up these domains in the same direction. Fundamental data developed by physicists working in fields far removed from minerals beneficiation are now available for developing better magnetic separators for ore processing. More Data Needed on Magnetic Properties of Minerals: There is less information on magnetic properties of minerals than there is for certain aspects of magnetic separator design. When the data on magnetic properties is available, it is often directed toward the study of powders for tape recorders and other highly scientific endeavors that are of little use to the beneficiation engineer. W. R. Crane&apos;s table of tractive forces, published in 1902, is still a guide in the study of magnetic minerals. Bits of other information regarding electrostatic conductivity, dielectric constant values, and permeability of various minerals have also appeared but are of small practical value in magnetic separation of ore. It is extremely important to obtain pure mineral specimens for making investigations and to record results that may be of use in studies of magnetic processes. Reference to the large volume of data developed by those concerned with analysis and design of permanent magnets soon reveals that these people have extensively evaluated the effect of various impurities on magnetic properties. Much of the science of the ferrite industry is based upon spinel-type structures which are varied by substitution of selected elements or even subtraction of elements, leaving vacant sites in the space lattice. Magnetic separators are used to beneficiate a wide variety of industrial minerals. In this application the relatively large volumes of nonmagnetics are usually the commercial products. The amount of mag-

Jan 1, 1959

Jan 1, 1941

By G. A. Croes, N. Schwarz

This paper reports the results of a series of model displacement experiments carried out for measuring the efficiency of the water-drive process. This series forms a continuation and extension of that described by Engel-herts and Klinkenberg. Detailed information has been obtained on the influence of the oil/water viscosity ratio. The results are represented in the form of a diagram from which both the oil recovery and the water/oil ratio can be easily read off as a function of the total production (oil plus water) for all values of the viscosity ratio M between I and 500. These resu1ts are viewed in the light of the two existing theories on water flooding, viz. that of Buckley and Leverett and that of Dietz. It is shown that if the Buckley-Leverett theory applies, the relation between the relative permeability ratio and saturation, which plays a major role in this theory, (.an be calculated with a high degree of accuracy from the results of the model experiments. Dietz&apos;s theory is found to be in agreement with the experimental results in a certain range of circumstances. A discussion of the physical background of the Buckley- Leverett and Dietz theories makes it clear why the latter fails to agree with some of the experimental results. INTRODUCTION For an economical exploitation of oil fields both a rational control of natural (primary) recovery processes and a proper application of artificial (secondary) recovery methods are essential. These require detailed information upon the dependence of the relevant flow processes on the variables by which they are governed. Three methods are available for obtaining this information: (1) (statistical) analysis of actual field data; (2) appropriately scaled model experiments; and (3) mathematical analysis of the physical problem. If sufficient data were available, the first method would, in principle, be the most reliable one, although it has the drawback that the basic relationships between the variables involved are to a large extent obscured by the natural inhomogeneities of most reservoirs. The most profitable procedure seems to be: (a) determining the fundamental relations for idealized reservoirs by methods (2) and (3); (b) checking the consistency of the results obtained by these two methods; and (c) establishing the range of applicability of these methods to actual reservoirs by comparison with the data accumulated under (1). In this paper items (a) and (b) are dealt with for the case of homogeneous loose sands initially saturated

Jan 1, 1956

By Eugene McAuliffe

TWO years ago the American Institute of Mining and Metallurgical Engineers made a memorable contribution toward a better understanding of the problems that have for many years confronted the coal industry. Specific suggestions toward betterment were then advanced, certain of which were taken up, amplified and endorsed by men who were conscien-tiously interested in the work of lifting this great industry out of the morass it has lain in for years. Two certain suggestions then made-provision for seasonal variations in railroad freight rates that would tend to encourage the purchase and movement of coal during the low summer production period, and provi-sion for the collection by the United States Government of all the facts surrounding the industry-were intro-duced in the form of legislation in the United States Senate by a member of that body, a man whose personal character, antecedents and business training put him above and beyond all suspicion of demagoguery; however, as the result of the insistent, vindictive opposition of the industry itself, these two bills, con-structive in their nature, were buried under an ava-lanche of misrepresentation. Today, with all mines that employ union labor at a stand still, the work of stabilizing the industry is yet before us. As aptly stated by Herbert Hoover, in March, 1920, when he was president of the Institute; An engineering organization is particularly the body to under-take this work. It is an economic problem, an engineering pro-blem within the ken of our experience; it is a problem that requires not only constructive thought but quantitative thought and wise social thought. The engineers of the United States occupy a position midway between capital and labor. They enter upon problems of this kind without prejudice either way, and they have that faculty of mind for quantitative thought, as distinguished from qualitative thought, that takes such problems as this out of the region of politics into the region of matter-of-fact solution.

Jan 5, 1922

By J. Groyecki, M. Markuszewicz, J. Lassota, A. Zawada

The ratio of stable to unstable inclusions was found to ploy an essential role in the process of sccorldar-y recrystatlizalion in Si-Fe. The analysis of the free energy of inclusions in the range of heat-treatment of individual inclusions to be predicted. The effects MnS. ns inslable inclusions. were investigated. TO secure a high induction, the secondary recryslulliztt-lion associated wilh the texture is necessary. To obtain a low core loss an additional refiuing in the solid state is required. It has been found that sulfur can be more easily removed in racunm than in hydrogen and thai this process was hindered by the prescrzce of INCLUSIONS play an essential role in the development of cube-on-edge texture in Si-Fe. Their function consists in restraining the growth of primary grains up to about 900°C and in passing subsequently into solution at higher temperatures. This process is accompanied by the selective growth of secondary grains with (110)[001] orientation. The general effect of inclusions depends on such factors as the type of impurities, their amount. dispersion and stability, the conditions of diffusion in the space of lattice of metal, and the reactions at the metal/gas interface. In recent years, some of these factors were the subject of a special investigation. A positive influence of Mns, siN,&apos; and vN3 has been established. The quantity of impurities4 and their dispersion5 have been found to be of major importance. Attention was called to the vital importance of diffusion and the conditions under which the impurities are removed from metal., It has also been demonstrated that in Fe-Si alloys by the techniques of powder metallurgy a special opportunity exists to obtain the (110)[001] type texture. 6 The aim of this work was to conduct qualitative investigations on the influence of inclusion stability on the development of cube-on-edge texture in a metal containing approximately 3 pct Si. Experiments were carried out on cast alloys and on those manufactured by powder-metallurgy techniques. The results obtained from these experiments were utilized to explain the phenomena involved and to analyze the relationships between stable and unstable inclusions and the magnetic properties of alloys. EXPERIMENTS AND RESULTS The raw materials used in these experiments were the powder of carbonyl iron with the analysis (in pct) 0.044 C, 0.01 Mn, 0.005 Si, 0.009 P, 0.002 S, traces of Cu, 0.06 Ni, 0.0015 Al, 0.03 Cr, 0.02 Mo, 0.01 Ti, 0.002 Co, traces of Pb, and the powder of silicon containing 94.14 Si, 0.003 S, 0.048 C. The powders were ground and mechanically mixed in 100-g batches. and then pressed at 9 tons per sq cm into 74 by 24 by 8 mm blocks. Sintering was carried out at 1100°C for 12 hr in vacuum (2 x lo-&apos; Tr) or in hydrogen. In this instance the material was heated slowly and subjected to prolonged soaking at 350°, 650°, and 750 2C, respectively, to secure reduction of ferro-oxides. This was checked by making measurements of the dew point, which was found to change from -15" to -35°C after reduction. The compacts after sintering were hot-rolled to 2.4 mm, annealed at 800 C, and finally cold-reduced to 0.35 mm with intermediate annealing at 800°C at a gage of about 0.8 mm. Impurities were added in the powdered form and mixed with iron and silicon powders. Sulfur in the elemental state, electrolytic manganese, and pure aluminum oxide were employed. Besides, to obtain a material with low contents of impurities, especially

Jan 1, 1967

By R. Dawson Hall

The stresses in the simplest structures are often those we find most difficult to analyze. The most complex condition in mine stresses is found in simple tunnels where the roof, the sides, and the floor are a monolith. The functions of the parts are like the parts themselves not distinct and spccialized, and the problems to be solved are like those in a metal structure with riveted joints or a redundancy of bars. This difficulty explains perhaps why the condition has not been treated. But just because it cannot be discussed in its entirety is no reason why it should be treated as an action of parts with spccialized functions as a roof beam with supports and a foundation. The problern cannot be ignored on the ground that it is not of sufficient importance to warrant careful consideration, because conditions of complete monolithism, of which the tunnel is the type, are found materially unchanged in room-and-pillar and in longwall work. This unity between roof, sides, and floor, which to the coal miner is a difficult conception, really deserves a scientific appellation, and perhaps holoid (from holos, whole, and eidos, form) will serve the purpose as well as any other. In a simple tunnel the roof, the sides, and the floor form integral parts of one and the same structure, and the distortion of one cannot be conceived without a consequent strain in the others. Thus when the roof of the tunnel droops by reason of its weight, the upper parts of the sides are drawn in becausc they are integrally connected with the roof and must approach each other whenever, by the sagging of the roof, the distance between any two points in it is diminished. (See Fig. 1.) Thc sides in their turn operate on the floor of the holoid structure, producing a tensile stress. The writer has always been impressed with the value of soap as a means of illustrating the action of mine stresses. With that idea in mind&apos; a cake of naphtha soap measuring 43/8 by 2¼ by 19i in. was taken and a tunnel was made through it 13/4 in. long, 21/2 in. wide and 1¼ in. high. (See Fig. 2.) A load was then placed at the mid-span of the tunnel. Eventually, the upper bar, or "roof," broke at the

Jan 1, 1916

By C. M. Schwartz, A. P. Young

ZIRCONIUM is noticeably embrittled at room temperature by hydride precipitate not only in notch-impact tests but also in tensile-impact tests.&apos; The embrittlement in slow-strain tensile samples is much less severe. To understand better the relationship of the hydride precipitate to the strain-rate effect in tensile samples, the surfaces of chemically polished zirconium tensile samples strained at a slow rate (0.03 in. per min head speed) and at an impact rate (18.1 fps hammer speed) were examined in the light and electron microscopes. Vacuum-degassed samples and hydrogenated samples (100 ppm hydrogen) were examined. The hydrogenated samples were slow cooled from 800°C. The most apparent difference between slow-strain and impact tensile samples was the preponderance of twinning over slip in impact samples as opposed to relatively little twinning in slow-strain samples. The twin bands in hydrogenated samples often terminated on hydride needles as seen in Fig. 1. Almost opposite the twin terminus is a fine crack and a nearly round fissure. Holes near the areas where single lens-shaped twins or opposing pairs terminate on hydride particles also could be seen In the light micrbscope. Quite frequently, microcracks associated with a partial row of hydride particles were visible, as in Fig. 2, indicating that the crack was parallel to a row of hydride particles. Some samples were chemically polished after straining to remove metal with a minimum of disturbance of internal voids. Fig. 3 shows a crack in the interior of a hydrogenated impact sample. Holes along grain boundaries were seen after impact in both degassed and hydrogenated samples. Very few microcracks were seen in degassed samples after impact or slow strain, or in hydrogenated samples after slow strain.

Jan 1, 1959

By Babbitts and Solder

G. w. Thompson,* Brooklyn, N. Y.—This subject has two aspects, neither of which can be ignored: these are the economic aspect and the technical aspect. Under ordinary conditions, economic law will take care of the conservation of tin. Under present conditions it seems desirable that economic law should still be permitted to operate as far as is practicable. It is true that this law operates rather slowly, and that under war conditions it cannot be depended upon to give our Government the supply it immediately needs. There should, therefore, be a designation of the essential industries by the Government, and tin should be supplied for those needs, letting the non-essential industries take what is left. At the same time, information ought to be forthcoming as to how tin can be conserved; with tin selling at 80 c. per pound, more or less, it is to the interest of every consumer to get the best information he can as to how he can save tin. Economic law would properly punish those who do not study their own interests in this way. I deprecate, therefore, any centralized socialistic effort toward avoiding penalties through failure to observe and obey economic law. In saying this, however, I am not unmindful that it is desirable for our Government to take such control of the tin situation as may be necessary to the prosecution of the war, practically regardless of the effect of such action upon individual industry, which should studiously seek to adjust itself to the new condition. The Government should promulgate such technical information as it can collect, showing how .tin can be conserved, and should urge upon every consumer the exercise of his common sense in self-protection. There is very little danger of any one attempting to hoard or corner tin, in the present state of the market. Most consumers will be glad to live from hand to mouth, covering their sales by purchases, or vice versa. As to the technical aspects: Tin and tin alloys are used to give certain practical and also certain artistic results. The practical factors are those involved in proper adhesion, continuity of surface, protection, the right degree of hardness, proper working qualities, etc. The artistic results are those that appeal purely to the eye or to our cultivated sense of what is desirable. There is no doubt that a great deal of tin could be saved if there were not a demand for certain pleasing effects. Row can this saving be brought about? The users of tin bearing alloys are not the only ones involved in this question. The manufacturers of solder and babbitt have for a long time sought to give certain appearances to their fabricated bars and ingots in order to make them more salable. The user of a solder is very apt to judge of its working qualities by the appearance of the bar; the same thing is true with regard to babbitts. Under ordinary conditions, manufacturers are justified in trying to

Jan 1, 1919

By Charles H. Shamel

I fear most of the Institute members are already weary of the perennial controversy about the apex law. I feel that way about it myself now, though I have been guilty of considerable contribution- to the discussion in the past. The discussion does not seem to perceptibly influence previously held views and I would not again break into print on the subject but for the urgent invitation of the Chairman of our Law Committee. This energetic and able member has firmly determined to secure a revision of the mining law and among other things to eliminate the so-called apex provision from the U. S. mining statutes. He is, however, fair about it and has invited me to make ((the strongest possible argument in its favor." I am suspicious that he is acting on the psychological principle that it is usually easier to convince an audience against a cause vigorously but unsuccessfully defended than against one wholly mute. Nevertheless, I realize that personally he wishes me no harm, much as he hates the apex law, and so am willing that the Institute have whatever benefit may accrue from my taking up again the unpopular side of the discussion. I say this because the attitude of a large part of our "articulate" membership seems irreconcilably hostile; their minds are made up; favorable consideration is foreclosed; and they become impatient and even sarcastic at any attempt to elucidate a favorable view of the apex law. The exact question for discussion at the present time is not whether on abstract, or any other considerations, the apex law is the best possible rule, but the very different proposition whether, after nearly 50 years of statutory life and much longer as a practically universal miners&apos; custom, it is now just and expedient to repeal the apex law. At this point it seems to me that we may profitably devote a paragraph or two to the subject of the origin of law in general, as we are presumed to be considering the subject from the high viewpoint of the general welfare of the nation. The most comprehensive and accurate definition of law in the legal sense is, that it is the body of rules for the regulation of human conduct which is enforced by the State, that is, by the nation.l Legal

Jan 1, 1915

Jan 1, 1946