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By L. K. Welch, C. W. MacGregor

The past 20 years has seen a revolutionary change in the testing of materials at elevated temperatures. This has largely been brought about by the practical importance of the creep problem in the design of equipment for operation at high temperatures. The short-time tension test carried out at elevated temperatures has consequently assumed in many cases only a secondary role compared with the longtime creep test. In many problems, however, a knowledge of the short-time high-temperature properties of a metal is essential. To mention a few cases in which this is so, we might include all hot-forming operations such as rolling, forging, etc., the welding problem if residual stresses are to be computed, the development of new alloys for high-temperature service where, in the initial stages, time does not permit of long duration creep tests, and others. Usually a knowledge of the short-time properties is desired, if only to serve as a background against which to compare creep behavior. In conducting short-time high-temperature tests, it has been almost the universal practice to determine stresses based on the original area and strains referred to the original gauge length which is usually chosen as 2 in. It has been pointed out1,2 that one of the reasons that the true significance of certain tensile properties is not understood, which perhaps curtails their usefulness, especially when the material is applied under conditions differing considerably from the test conditions, is that true physical stresses and strains are not determined. It is essential to have a knowledge of true stresses and strains in order to correlate the values present in the tension test with those existing, for example, in hot metal-forming operations and in the general problem of the yielding and failure of metals under combined stress conditions. Stress and strain values based on the original dimensions of the test piece do not exist physically except in the early stages of the test. Since at the present time there is very little information in the literature on true stress-strain relations in the short-time high-temperature tension test it is proposed in the following pages to describe a

Jan 1, 1943

By G. R. Speich, S. A. Kulin

The isothermal formation of martensite at subzero temperatures has been studied in an austenitic stainless steel. The amount of martensite formed isothermally in a given time was found to follow a C-curve behavior with decreasing temperature. Since isothermal rnartensitic transformation occurs at temperatures above the true M. temperature of the olloy, the observed M. temperature is dependent on the cooling rate. It is believed that a general martensite theory must include the basic concepts of the strain embryo theory, and also the important role of thermal fluctuations. UNTIL recently the isothermal component of the martensitic transformation had been considered as a trivial effect in theoretical considerations of this type of transformation. One of the postulates used in defining a martensitic transformation was that the reaction was temperature dependent but not time dependent. Cohen and his associates1'2 were the first to report the isothermal formation of mar-tensite. They obsel-ved the time dependency of the martensite reaction at room temperature in plain carbon steels and certain tool steels. They found that a small amount of additional transformation occurred after the specimen reached the quenching temperature and that the rate of this isothermal transformation decreased rapidly with time. These authors considered this phenomenon to be a "tailing-off" of the main athermal reaction. Kurdjumov and MaksimovaL 5 studied the isothermal formation of martensite at subatmospheric temperatures in steels containing 0.6 pct C-6 pct Mn, 1.6 pct C, and in an iron-base alloy containing 23 pct Ni and 3.4 pct Mn. In each case it was found that both the initial rate and the total amount of isothermal transformation exhibited sharp maxima with decreasing temperature. They stated that it was possible to completely suppress the martensitic transformation in the 0.6 pct C-6 pct Mn steel by drastic quenching in liquid nitrogen. They interpreted their results in terms of a thermally activated process. The maximum in the rate of nucleation vs. temperature curve was assumed to be a result of the temperature dependence of the rate of growth of the martensite plates. It has been demonstrated," however, that martensite plates can form with great rapidity even at temperatures approaching absolute zero. In addition," attempts to confirm the reported suppression of the martensitic transformation by rapid cooling of a 0.6 pct C-6 pct Mn steel have proved unsuccessful. On this basis, and on other theoretical grounds, the validity of some of Kurd-jumov's results and conclusions is open to serious question. Cohen, Machlin, and Paranjpe' have proposed a theory of martensite formation based on the nucleation of strain embryos and a growth mechanism involving cooperative atomic displacements. According to this theory thermal fluctuations can make a strain embryo supercritical and thereby produce martensite isothermally. Das Gupta and Lement' have investigated the isothermal formation of martensite in a 17 pct Cr-0.7 pct C steel at temperatures below the ambient. They found that partial suppression of the martensitic reaction occurred on quenching into liquid nitrogen. That part of the reaction which can be suppressed is taken to correspond to the isothermal rather than the athermal part of the rnartensitic transformation. The initial rate of isothermal transformation for this steel was found to go through a maximum with decreasing temperature. This is in conformity with the findings of Kurdjumov and Maksimova for the steels used in their investigation. Das Gupta and Lement conclude that isothermal martensite formation occurs by the nucleation of new plates and is always preceded by some athermal transformation. An iron-base alloy containing 14 pct Cr-9 pct Ni was used in this investigation to study further the kinetics of the austenite to martensite transforma-

Jan 1, 1953

By W. B. Devereux

The special mriditions under which gold occurs in the Potsdam formation of the Black Hills prew~lt features worthy of a more systematic pesentation than they have heretofore received. The notes

Jan 1, 1882

By T. Kilner, A. Plumtree

DURING an investigation of electro-deposited silver structures, samples were prepared for metallographic examination by cold mounting in plastic, grinding on successive grades of emery paper down to 3/0, and chemically polishing by swabbing using the chromic acid solution described by Gilpin and Worzala.1 Attempts to etch these samples using the standard solutions described for silver (e.g., 5 pet KCN-5 pet Na2S2O8, H2O2-NH4OH, and various potassium dichro-mate solutions) all failed to give good results due to staining of the samples and to rapid etching. The staining was caused by the chromic acid polishing solution being trapped in small fissures between the sample and the mounting plastic, and also in small fissures in the sample itself. To overcome these difficulties, an etchant was developed which prevented staining at the same time as it slowly etched the sample. This resulted in a very clean, crisply etched surface as shown in Figs. 1 and 2. This etch consisted of 10 ml of orthophosphoric acid, 10 ml of distilled water, and 2 drops of the polishing solution noted above,' which is made by mixing 100 ml of saturated CrO3 solution, 45 ml of 10 pet HC1 solution, and 800 ml of distilled water. The etching procedure involved taking the final polished sample, either immersing or swabbing in the etchant for a period of 1 to 2 min, rinsing as quickly as possible in distilled water, alcohol, and ethyl ether in that order, and then immediately drying. This etch is easily controlled due to its slow rate of etching, and produces samples with clean, sharp surfaces. Pits due to overetching produced varying contrast effects when viewed under polarized light, and are therefore obviously useful for revealing many structural details within the sample. Another effect of overetching was to produce a height varia-

Jan 1, 1968

By Royal B. Jackman, Carle R. Hayward

Two comprehensive papers have appeared regarding the forms of copper that occur in smelter slags, one by Frank E. Lathe1 and the other by C. G. Maier and G. D. Van Arsdale.2 These authors comment on other published results and draw conclusions from their own investigations. The development of X-ray examination of minerals and improvement in high-power microscopic methods make it possible today to get additional evidence by means that were not available to earlier investigators. The present work was confined to reverberatory slags obtained from five different plants. Some definite conclusions were reached regarding the forms of copper present in these slags. In most cases these agree with some of the findings of Maier and Van Arsdale but new methods of attack were used in the investigation. Conclusions of Previous Investigators Various important conclusions reached by previous investigators are summarized in the following paragraphs, arranged chronologically. William A. Heywood:3 Slag losses increase with grade of matte but with the same grade of matte losses decrease as the acidity of the slag increases. Lewis T. Wright:' Slag losses are only partly due to prills of matte. It is suggested that part of the copper is dissolved in the slag. J. Parke Channing9 A considerable part of the copper enters the slag as silicate or oxide and not as sulfide. C. A. Grabill:6 Slag losses are both physical and chemical. Physical losses, due to poor settling, gas flotation and slight differences in specific gravity, are small under normal conditions. Chemical losses may- be due to formation of oxides or to solution of metals and sulfides. The last is considered the most important. John W. James:' The copper in converter slag is largely the oxide and as such enters the reverberatory slag when converter slag is added to the charge.

Jan 1, 1934

By Granville S. Borden

The fruits of industry are divided between capital, labor, and governments. Capital takes its redemption and remuneration through profits or dividends; labor takes its share through wages; governments take their share through taxes. Each must have a just share, and the question of what is a just share and the question of who-shall make the allocation are vital current political and economic issues. Certain political philosophies con- tend that government should take all the fruits and that some dictator or politician should have irrevocable discretion and power to distribute the fruits. Believers in democracy and free enterprise adhere to the view that capital is entitled to redemption and fair remuneration; that labor shall have a fair wage; and that governments shall make equitable levies. But since all human beings, both individually and in groups, are inherently selfish, there are many variable views in regard to the question of what ratios shall be applied in a division of the fruits and who shall have the power to fix these ratios. Perhaps all parties should devote more energy to means of increasing the crop, and not so much time to quarreling over a division of the existing crop. Moreover, all three parties must guard against killing the goose that lays the mineral eggs. For example, if the tax burden becomes oppressive and the taxpayer refuses to carry it, then business stagnates, with consequent unemployment, reduction of profits, and curtailment of government revenue. If a producer assumes the increased tax burden, marginal operations must be closed down, and again the consequences are increased unemployment and diminished government revenue. Quite often an increase in a rate of tax results in a reduction of government revenue. Perhaps the worst detrimental feature of selfishness and greed on the part of any one of the three distributees of the fruits of industry is the retardation of expansion of the enterprise. Growth means new jobs, more government revenue, better trade, and better standards of living. Explorations and discoveries have resulted in tremendous contributions

Jan 1, 1959

By Albert E. Reed

THE development of the modern high-speed vibrating screen, together with the increasing availability of long-lasting stainless-steel screen cloth for relatively fine-mesh separations, means that more screen circuits will be used in the future. It seems pertinent therefore to examine a few characteristics of screen-circuit products, and especially the points of difference as compared with products of classifier circuits. The most noticeable change that takes place when substituting screening for classification in a grinding circuit is a substantial drop in the circulating load, owing to the greater ease with which the "fines" leave the circuit. Where circulating loads of 500 to 600 per cent are considered fairly normal in classifier grinding circuits, the grinding circuit equipped with screens for equivalent work will have a circulating load of only 20 to 75 per cent. As a result, the products of screen circuits will show a minimum of overgrinding or sliming as compared with a classifier circuit. The desirability of this characteristic will naturally vary according to the metallurgical requirement in each case. Because screen separations make a sharper division according to particle size, the products of screen circuits can be expected to show greater crowding of particles near the point of separation. These changes in product characteristics are so important that other factors, both in the grinding and concentration processes must be adjusted if the operator is to take full advantage of the increased tonnages and higher efficiencies available to him through the use of the screen circuit. One factor that too often is overlooked when changing to screen circuits is the importance of adjusting the ball-mill or rod-mill charge, to compensate for: (I) increased tonnage of new feed, (2) decreased circulating load, or (3) more granular character of feed. These same factors should also be taken into consideration for their effect on the various types of concentration or flotation equipment that may follow the screen circuit. Over a period of years, this equipment has generally been designed and adjusted to the product of the classifier, therefore it seems obvious that some research on the adjustment and adaptation of concentrating and flotation equipment to screen-circuit products will be most profitable to the operators. To illustrate the points mentioned above, the results from three recent installations follow, with data on the comparative characteristics of screen and classifier circuits. A range of separation from 10 to 48 mesh has been chosen, using two general types of screening equipment and two types of classifiers. The first of the installations of which the results are to be examined is that of an iron-ore installation where eastern magnetite was being concentrated prior to sintering. Fig. I shows the original grinding circuit, using classification, while Fig. 2 shows the same circuit equipped with a

Jan 1, 1945

ANY discussion of State-supported schools of mining and metallurgy needs to be prefaced by a definition, since the first school to offer a mining curriculum, the Pennsylvania. Polytechnic College, was established by a grant from the State. But, so far as can be determined, it received no further State support. It would be tiresome to go into precise details, and it will be enough to stipulate that by State schools are meant those which derive their main financial support from regular appropriations made by a State legislature. The University of Michigan was the first of these to. offer a mineral industry curriculum; its story, as well as those of Wisconsin and Illinois, has been related in the preceding chapter.* Arranging the others in chronological order involves making a decision as to what weight to attach to plans for giving instruction, as contrasted with its effective initiation. This may appropriately be illustrated by the history of mineral industry education in California. CALIFORNIA Among those who came to California in 1849 and the following years were many New Englanders who had a keen interest in education. Some of them, mostly Congregationalists and Presbyterians, sought to establish a school of higher education around San Francisco Bay and eventually succeeded in opening the "Scientific and Classical School at Contra Costa" in Oakland, at Broadway and 5th St., on June 90, 1853. This prospered so well that it was chartered by the State as the College of California" on April, 13, 1855. Developing so rapidly that its quarters became. cramped, in 1864 it not only bought a tract of

Jan 1, 1941

By A. M. Gaudin

THIS paper presents, with the help of colored photomicrographs, the new method of mineral identification termed "selective iridescent filming." This method pertains to the field of determinative mineralogy, which it provides with tools for: (1) phase identification, (2) solid solution analysis. The method should be particularly useful in the applied fields of: (1) paragenesis of ore deposits, (2) mineral dressing, (3) mineral synthesis and study of phase equilibria.

Jan 1, 1938

By K. K. Kershner, W. A. Calhoun, C. W. Funk

Future resources of aluminum may require the utilization of low grade ores to provide a more permanent protection for the nation. Aluminum minerals such as cloy, shale, and high iron laterites may become important sources. An evaluation of reserves is given. New laboratory results are reported on the Vereinigte desilication process. THIS report on future resources of aluminum metal emphasizes the necessity for investigating utilization of low grade potential ores to provide more permanent protection for the nation. Partial or complete interruption of the importation of high grade aluminum ores must be given consideration. Ultimately, aluminum minerals such as clay, shale, and high iron laterites may become the principal sources of aluminum. The development of extractive processes for treating these low grade materials is a step in long-range national preparedness that should receive more attention. In formulating such processes, the application of beneficiation methods for the purpose of classifying the several types of minerals before subjecting each type to the more expensive extractive procedures should be considered, and a careful survey of the basic factors of power sources, transportation facilities, and sources of raw material should be made. Domestic Bauxite Resources Of the domestic supply of current, treatable-grade bauxite, 95 pct comes from Arkansas. The present reserve of Arkansas bauxite suitable for metal production, including abrasive-grade, Bayer-grade, and modified Bayer-grade ores, is 34,000,000 tons. The total reserve of bauxite of all grades is approximately 75,000,000 tons. Reserves are estimated on a mined and dried basis. Data available to the Bureau of Mines in 1948 to 1949 were used in preparing Table I, which shows a breakdown by grades of bauxite for about a half of the reserves of the state. The modified Bayer ore, 10,555,500 long dry tons, is based on a cutoff of 8 to 15 pct silica. The sub- marginal 10,074,700 long dry tons is assumed to contain more than 40 pct gibbsite, more than 15 pct silica, and less than 32 pct available alumina. A considerable amount of this low grade material was consumed in 1949 and 1950. Additional tonnages of bauxitic and kaolinitic clays are indicated by the Bureau of Mines drilling project.' Applying a 50 pct factor to arrive at long tons mined and dried, the results of this project are approximately 31,500,000 tons kaolinitic clay at +35 pct Al²O3 and 11,800,000 tons kaolinitic clay at 20 to 35 pct A1,0,. Total reserves of kaolinitic clays are probably quite extensive—several times the reserves shown in the Bureau's work. Total reserves of bauxitic and high iron clays from the drilling program and previously established figures are 63,980,000 tons. The mineral dressing methods,' the lime-sinter process, he lime-sinter modification of the Pederson process," the lime-soda sinter process,"-' and the Alcoa combination processa. have been described in the literature and will not be elaborated upon here. The less familiar Vereinigte Aluminium-Werke process used by the Germans during World War 11 may require some amplification. It was used to bene-ficiate boehmite ores containing 12 to 18 pct silica for a feed to the European Bayer process. Ore was

Jan 1, 1952

By Wilson T. Lundy

The history of the production of sulfur from salt domes in Louisiana and Texas originated with the operations of the Union Sulphur CO. at Sulphur, La., followed by the Freeport Sulphur Co. at Bryanmound, Tex. Including the present development of Grande Ecaille by the Free-port Sulphur Co., which constitutes the tenth dome to be equipped for the production of sulfur in the Gulf Coast, less than 10 per cent of all the known domes have proved to contain sulfur in commercial quantities. The Grande Ecaille salt dome is in the tidal marsh of the Mississippi River delta in Plaquemines Parish, Louisiana. It is 10 miles southwest of the right descending bank of the river approximately 45 miles below the city of New Orleans and is within 4 miles of the shore line of the Gulf of Mexico. Terrain Characteristic of the delta region, the terrain consists of a low, flat, uninhabited area of marsh land intersected by many shallow lakes and bayous. With the exception of salt grasses, the region is devoid of vegetation and presents, in all directions, an unobstructed path to the vagaries of the winds. The general character of this area can be best visualized from the mechanism of its formation.' Offshore bars formed enclosing long narrow lagoons between the bar and the inner shore line, the lagoons communicating with the sea by means of tidal inlets. The water in the lagoons, being comparatively quiet, favored the deposition of fine debris composed of sand carried into the lagoons by action of the waves, tides and river-borne sediments from the land surface. As this material accumulated the bottoms of the lagoons were built up and eventually salt grasses obtained a foothold. The successions of growth and decay of these grasses formed a brown fibrous mat varying in depth from a few inches to several feet. This mat of vegetation virtually floats on an ooze that is several feet thick and is composed of alluvial sediments and very fine sand, and the whole is underlain by an unctuous clay. The decayed vegetation from the upper layer when dried has a peaty appearance.

Jan 1, 1934

By A. H. Geisler, R. F. Mehl, S. Barrett

The studies of the mechanism of pre= cipitation and of the resulting property changes in aluminum-silver alloysl-3 have presented some new concepts of the aging reactioxl—concepts that may be fundamental in establishing a complete quantitative theory of age-hardening. With both aluminum-copper and aluminum-silver alloys, thin platelike aggregates form parallel to the Widmanstätten planes of precipitation.l,4 These platelets grow in lateral dimensions and in thickness with aging time until they arc thick enough to produce an X-ray diffraction line pattern. Their structure is that of a transition lattice which is coherent with the matrix, since the atomic spacings in the matrix and the precipitate are the same on each side of their common interface.2,4 The equilibrium precipitate forms later from and at the expense of the transition lattice. Since age-hardening occurs during the formation and growth of the transition lattice, the major contributor to the hardening no doubt is the stress condition in the matrix resulting from the matrix holding the precipitate in the coherent condition. The development of these stresses also appears to be responsible for an increase in the electrical resistance superimposed on the normal decrease resulting from a change in the concentration of the matrix during aging.3 The two consecutive reactions constituting the aging process are accompanied by characteristic microstructural alterations. The initial precipitation process results in the formation of a Widmanstatten figure, while the later transformation of the transition lattice to the equilibrium lattice is accompanied by a coalescence, in the case of aluminum-copper alloys,5 and by the appearance of light areas at the grain boundaries with aluminum-silver alloys showing a structural rearrangement of matrix and precipitate.3 This latter reaction is similar microscopically to the so-called "discontinuoils precipitation." Possibly discontinuous precipitation is a process that often if not always follows true precipitation of a coherent lattice and during which the transformation of the coherent transition lattice to the equilibrium lattice takes place accompanied by matrix recrystallization.3 Expermental Procedure The alloys were made using 99.97 per cent A1 or distilled magnesium, with

Jan 1, 1943

By R. F. Mehl, A. H. Geisler, S. Barrett

The studies of the mechanism of pre= cipitation and of the resulting property changes in aluminum-silver alloysl-3 have presented some new concepts of the aging reactioxl—concepts that may be fundamental in establishing a complete quantitative theory of age-hardening. With both aluminum-copper and aluminum-silver alloys, thin platelike aggregates form parallel to the Widmanstätten planes of precipitation.l,4 These platelets grow in lateral dimensions and in thickness with aging time until they arc thick enough to produce an X-ray diffraction line pattern. Their structure is that of a transition lattice which is coherent with the matrix, since the atomic spacings in the matrix and the precipitate are the same on each side of their common interface.2,4 The equilibrium precipitate forms later from and at the expense of the transition lattice. Since age-hardening occurs during the formation and growth of the transition lattice, the major contributor to the hardening no doubt is the stress condition in the matrix resulting from the matrix holding the precipitate in the coherent condition. The development of these stresses also appears to be responsible for an increase in the electrical resistance superimposed on the normal decrease resulting from a change in the concentration of the matrix during aging.3 The two consecutive reactions constituting the aging process are accompanied by characteristic microstructural alterations. The initial precipitation process results in the formation of a Widmanstatten figure, while the later transformation of the transition lattice to the equilibrium lattice is accompanied by a coalescence, in the case of aluminum-copper alloys,5 and by the appearance of light areas at the grain boundaries with aluminum-silver alloys showing a structural rearrangement of matrix and precipitate.3 This latter reaction is similar microscopically to the so-called "discontinuoils precipitation." Possibly discontinuous precipitation is a process that often if not always follows true precipitation of a coherent lattice and during which the transformation of the coherent transition lattice to the equilibrium lattice takes place accompanied by matrix recrystallization.3 Expermental Procedure The alloys were made using 99.97 per cent A1 or distilled magnesium, with

Jan 1, 1943

By Samuel L. Hoyt

Cemented tungsten carbide, a product of a branch of metallurgy which has never possessed more than a relatively minor interest and importance, has recently commanded the attention of engineers, industrialists, financiers and men of business. New methods, new opportunities, new goals, never before considered, have suddenly been brought within the scope of practical realization. It is these results that attract the interest of the world, but we, as engineers and metallurgists, will have equal interest in the product itself and in that branch of metallurgy from which it comes. It seems appropriate, therefore, to speak today on Hard Metal Carbides and Cemented Tungsten Carbide, as the latter represents one of the outstanding developments of recent date in non-ferrous metallurgy. We are interested in the hard metal carbides as a group of related metallic substances and in cemented tungsten carbide as the leading representative of the metallurgy of this group. The literature of this general field is limited, and, bearing this in mind, it seems advisable to attempt to cover the field broadly and to correlate the subject matter, rather than to present a detailed account of any one of its phases. Our annual lecture lends itself admirably to this plan. The quickened interest in cemented tungsten carbide, once its potentialities were recognized, the many sides to the problem of developing the manufacture and use of this new product, and the desire to economize as much as possible in the time of development, have brought many into this work, both in this country and abroad, notably the Osram Lamp Co. and Friedrich Krupp in Germany and the General Electric Co. in this country. It would be presuming too much to attempt to speak too broadly of the present state of the art and science of the hard metal carbides and my remarks arc guided largely by the work done in the General Electric Co., and by our associates in the Carboloy Co. Even here the activities of many in these two groups have centered around the utilization of cemented tungsten carbide, which is outside the scope of this talk. To those whose work is represented in this lecture, it is my pleasant duty to acknowledge their assistance and advice. To Dr. Zay

Jan 1, 1930

By M. H. Merriss

Some years ago, at the plant of the Baltimore Copper Smelting & Rolling Co., the receipt of large quantities of copper blister running high in lead, nickel, and arsenic resulted in the formation of a great amount of very foul slag, in the anode furnaces. A typical analysis of this slag was: Gold, oz. per ton......... 0.09 Arsenic, per cent.......... 0.60 Silver, oz. per ton......'.. 13.20 Antimony, per cent........ 0.50 Copper, per cent......... 19.50 Silica, per cent............ 28.30 Lead, per cent........... 11.90 FeO, per cent............. 19.20 Nickel, per cent.......... 4.60 CaO, per cent............. 1.60 The problem was to get out the copper in marketable form, to save the gold, silver, and particularly the nickel, and to get rid of as much as possible of the lead, arsenic, and other elements that were valueless to the Baltimore plant. In a copper refinery that does not take custom material for matte smelting, the usual method is to smelt the anode slag with coke in a reducing furnace, the black copper thus formed being sent back to the anode furnaces; this was the custom at Baltimore. An average anode slag will contain, perhaps, 40 per cent. copper and such small quantities of lead, nickel, etc., that smelting will get rid of most of these impurities in the black-copper furnace slag. To treat such an impure slag in this way, however, would result in a large nickel loss, and would send back to the anode furnaces all the lead and nickel not so lost, where it would be slagged off again and returned to the black-copper furnace as a slag still more concentrated in impurities. The result would probably be a constantly increasing amount of anode slag containing a likewise constantly increasing percentage of impurities. To avoid such a disastrous closed circuit some other process had to be devised. A small multiple-tank room, built for impure copper as an adjunct to the main series electrolytic refinery, was available, so the following standard process was suggested:

Jan 1, 1924

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

E. A. Peretti (University of Notre Dame, Notre Dame, Ind.)—Mr. Deitz and Professor Halpern are to be congratulated on a fine piece of work which adds to our knowledge of precious metal—cyanide-solution reactions. I should like to offer the following comments: The authors state, "the rate plots were always linear, indicating a zero order reaction rate." This appears to conflict with the data of Fig. 6 which clearly show the rate to vary with the NaCN concentration. It seems to me that the rate curves are linear because of the experimental setup. The volume of solution is so large that over a three-hour period the change in NaCN concentration is very small. A rough calculation for the experiments of Table I where the initial NaCN strength was 0.0096 mol per liter show a change of NaCN concentration of about 0.0009 mol per liter at the end of three hours. In short, over the period of time that the experiment was in progress, the NaCN strength was practically constant; hence the rate of dissolution remained practically constant. Eq. 10, as written, specifies that 1 mol of H202 and 2 mol of hydroxyl ion are formed when 2 mol of silver react. Is this true? The effect of H,O2 on the rate was made in solutions having an oxygen pressure of 4.8 atm. Were any tests made in solutions containing hydrogen peroxide, but no oxygen? G. M. Willis (University of Melbourne, Melbourne, Australia)—The authors have shown that, under their experimental conditions of high O2 concentrations, the rate of solution of silver in aqueous cyanide solutions is controlled by diffusion of O2 or CN- to the metal surface. With diffusion control, it is generally not possible to obtain further information about the mechanism of a process.

Jan 1, 1955

By A. D. Hodges

In May, 1850, the first gold from the Comstock lode was discovered in the sands near the Carson river. It had been washed down by natural agencies, through Gold Caflon, from the decomposed rock of the ledge above. Within a few weeks, the precious metal was traced more than three miles in shallow deposits along the bed of the canon, from the river to the Devil&apos;s Gate-—a narrow, rocky cleft, notable to the teamsters of a later day chiefly as the place where " Uncle Jimmy Fair" collected high tolls, and could not reduce the rates, because " this was all he had for the education of his poor children." From 1850 to 1857, a fluctuating band of miners, whose number varied from twenty to two hundred, washed the Gold Canon placers with rockers and long-toms, making four to five dollars a day each until the last-named year, when the deposits were in great measure exhausted. The chief settlement of these miners was at Johntown. During only a third of the year was the water-supply sufficient for their work. The remainder of the time they utilized in desultory prospecting of the hills and in occasional forays for supplies among the Mormons in Carson valley. In 1857, the Grosch brothers discovered the Comstock lode at some point, now unknown, in Gold Hill, but their discovery perished with them. Early in 1858, the " Pioneer Quartz Company," having located several of the small surface-veins around Silver City (whose connection with the main lode has never been definitely shown), built an arrastra, and worked some of their ore; but the returns were so small that they soon abandoned this business. The following winter, James Finney and his partners found gold in place in

Jan 1, 1891

By William H. Spice

The fault zone of south central Texas showed renewed activity during I940 along a trend roughly paralleling the old established Balcones fault-line group of producing fields. This was a result of the new discoveries in the Wilcox (Eocene) formation in southeastern Texas and Louisiana. As of the end of the year, one new field producing from the Wilcox formation had been discovered on the Washburn ranch in La Salle County, along the southwestern limits of the district, and several projected tests into that formation were under way. In the western part of the district, par-titularly in the part of the Rio Grande embayment that is in Dimmit, Webb and Zavala Counties, there has been renewed leasing activity with the shallower sands in the Navarro-Taylor formations (Upper Cretaceous) as the objective in several projected tests for the early part of 1941. Three new fields have been discovered along the old fault-line trend, but these have been comparatively small, producing either from Dale lime, Austin chalk or Buda lime. No new fields were discovered during the Year in the Edwards (Lower Cretaceous) lime horizon. Approximately 260 wells were drilled in the district during 1940, which resulted in four new oil fields. Twenty-seven new wells were completed in the Proven Edwards lime fields of Darst Creek, Luling and Salt Flat and seven were added to production in the Pearsall field. Approximately 160 wells in 18 counties were completed as failures during the year. The district produced 7,659,634 bbl. during 1940, which was a 9 per cent decrease under production for 1939. In all, 3559 wells were producing at the end of I940, compared with 3562 wells producing at the end of the previous year; 104 new producing wells were completed and 163 wells were abandoned in the producing fields of the district. During 1940 considerable exploratory work was carried on along the Wilcox trend within the district, particularly by major companies employing various types of geophysical methods, and leasing activity increased considerably. At the end of the year, the total number of acres of nonproducing leases held by major companies in the district increased about 10 per cent. It is anticipated that this activity will continue into the first part of 1941 and will be supplemented by several exploratory test wells. New Fields B,, Creek, Caldwett County.— . R. Ogden NO. 2 Talley, discovery well of the Bee Creek field, in the northeastern part of Caldwell County, was completed on March 16, I940, in Dale lime from 2091 to 2238 ft., pumping 85 bbl. per day, 39° A.P.1. gravity. The discovery of this field can be credited to a combination of subsurface geology and magnetometer work, which indicated the presence of a serpentine intrusion. At the end of the year, ,3 producing oil wells had been completed and the field has produced a total of 47,050 barrels.

Jan 1, 1941

By William H. Spice

The fault zone of south central Texas showed renewed activity during I940 along a trend roughly paralleling the old established Balcones fault-line group of producing fields. This was a result of the new discoveries in the Wilcox (Eocene) formation in southeastern Texas and Louisiana. As of the end of the year, one new field producing from the Wilcox formation had been discovered on the Washburn ranch in La Salle County, along the southwestern limits of the district, and several projected tests into that formation were under way. In the western part of the district, par-titularly in the part of the Rio Grande embayment that is in Dimmit, Webb and Zavala Counties, there has been renewed leasing activity with the shallower sands in the Navarro-Taylor formations (Upper Cretaceous) as the objective in several projected tests for the early part of 1941. Three new fields have been discovered along the old fault-line trend, but these have been comparatively small, producing either from Dale lime, Austin chalk or Buda lime. No new fields were discovered during the Year in the Edwards (Lower Cretaceous) lime horizon. Approximately 260 wells were drilled in the district during 1940, which resulted in four new oil fields. Twenty-seven new wells were completed in the Proven Edwards lime fields of Darst Creek, Luling and Salt Flat and seven were added to production in the Pearsall field. Approximately 160 wells in 18 counties were completed as failures during the year. The district produced 7,659,634 bbl. during 1940, which was a 9 per cent decrease under production for 1939. In all, 3559 wells were producing at the end of I940, compared with 3562 wells producing at the end of the previous year; 104 new producing wells were completed and 163 wells were abandoned in the producing fields of the district. During 1940 considerable exploratory work was carried on along the Wilcox trend within the district, particularly by major companies employing various types of geophysical methods, and leasing activity increased considerably. At the end of the year, the total number of acres of nonproducing leases held by major companies in the district increased about 10 per cent. It is anticipated that this activity will continue into the first part of 1941 and will be supplemented by several exploratory test wells. New Fields B,, Creek, Caldwett County.— . R. Ogden NO. 2 Talley, discovery well of the Bee Creek field, in the northeastern part of Caldwell County, was completed on March 16, I940, in Dale lime from 2091 to 2238 ft., pumping 85 bbl. per day, 39° A.P.1. gravity. The discovery of this field can be credited to a combination of subsurface geology and magnetometer work, which indicated the presence of a serpentine intrusion. At the end of the year, ,3 producing oil wells had been completed and the field has produced a total of 47,050 barrels.

Jan 1, 1941