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By A. E. Schuetz, A. E. Roswell, W. R. Hibbard

THE drawn wire texture of body-centered cubic iron,' tungsten,' and molybdenum~ as been determined to be a [110] direction parallel to the wire axis. The purpose of this study is to extend the available information on body-centered cubic wire textures to other metals and alloys. Wires were produced using hand wire rolls and dies as given in Table I. In addition, attempts were unsuccessful to draw wires from chromium, vanadium (Vanadium Corp. of America), and tungsten (Cleveland Tungsten Inc.). Although it is known that wires can be made from these materials, suitable techniques were not readily adaptable. Where necessary, wires were polished and etched to form flat ribbons 0.005 to 0.007 in. thick, and transmission X-ray patterns were taken using molybdenum radiation with the specimen tilted 0 degrees from the perpendicular toward the beam to critically cover the wire axis. Analyses were made of (110), (002), and (112) reflection circles. In all cases reflection maxima indicated the texture to be a single [1101 deformation fiber, as illustrated by Fig. 1 for molybdenum. In the case of the hot-worked ß brass, a second texture, [loo], was also found, but this is believed to be the result of recrystallization since it has been reported for re-crystallized molybdenum wires' and it was not present in the cold-drawn ß brass. The difference in drawability between the 51.92 pct Cu ß brass and the 62.5 pct Cu ß brass (containing some grain boundary a due to incomplete quenching) is quite striking, since the latter could be cold worked readily while the former had to be hot worked to avoid cracking. Summary The deformation texture of drawn body-centered cubic wires of ß brass, iron, molybdenum, niobium, and tantalum is essentially a single [110] fiber as predicted by theory.' Acknowledgment The authors wish to thank the suppliers of the metals listed in the text, and the Grant-in-Aid from the Research Fund of the Society of the Sigma Xi and Scientific Research Society of America which made possible the purchase of X-ray equipment.

Jan 1, 1952

By Walter Miller

The broad picture of petroleum refining engineering during 1934 continued to show a tendency in the direction of highly specialized processing improvements, particularly in manufacture of lubricating oil. The slowing up of the trend toward higher octane products in non-premium gasoline noticed in 1933 was definitely established as a fact by 1934 development, with just a slight indication of recession. No outstanding engineering achievements can be credited to 1934 in refinery cracking, unless the completion and successful operation of the 30,000-bbl. crude capacity combination cracking and skimming unit at Texas City, Texas, and a 20,000-bbl. similar unit in the East can be listed as such. Development and improvement was largely a continuation of previous lines of endeavor. Such trend as there is shows a continnation in the direction of very large integrated skimming and cracking units. A lessening of the cost of ethyl lead, coupled with the reaching of the octane number "ceiling," kept the subject of "reforming" low-octane gasoline into high-octane products pretty well in the background. Considerable interest, however, was shown during the year in cracking and polymerizing of refinery gases into high-octane motor fuel. The commercial development and application of this activity was greater in 1934 than during any previous year. Fair yields of gasoline of satisfactory stability and high antiknock value were reported, ranging from 2 to 8 gal. per 1000 cu. ft. of fixed refinery gas, yields varying with both the nature of refinery gas treated and processing methods. Assuming economic feasibility, regarding which there is still difference of opinion, gas polymerization offers the industry a possible outlet for its gases more in keeping with its basic chemical composition and value. The increased interest of railroads and heavy-duty truck and tractor manufacturers served to focus more attention on diesel fuels. The publicity given the Union Pacific diesel train, the Burlington "Zephyr" and others operated on special diesel fuels served to revive the intimations and fears of several years ago as to the ultimate replacement of the gasoline motor by diesel engines in even the passenger car field. How-

Jan 1, 1935

TO THE BOARD OF DIRECTORS OF AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen:-I have the honor to present the following, report for the calendar year 1920. The activities which seem to call for special comment are: THE NEW FORM OF MAGAZINE MINING AND METALLURGY appeared every month during the calendar year and has been developed until it contains some ten departments. It has brought forth more commendatory letters than have been received at headquarters on any other subject throughout the year. Less than a dozen letters unfavorable to the change have been received, and the indications are that the magazine has met a want deeply felt, especially by members distant from headquarters. The technical papers printed by the Institute are published in abstract in the magazine and opportunity is given to members who desire them to receive full copies of any or all papers published. The Bound Volumes, as usual, contain all the papers in full and discussions thereof. FINANCES The greatly increased cost of paper and printing has put a tremendous burden on the Institute's finances, since the dues of $12 per year are only 20 per cent. greater than the members paid when the Institute was founded forty-nine years ago. This has resulted in a temporary deficit, similar to that encountered by many of our sister engineering societies. The fact that our Institute has lower dues and gives more in the way of publications to its members than any other of the national engineering societies has rendered the situation more difficult for us. MEETINGS The Annual Meeting in New York, the Field Meeting in the Lake Superior District, the meeting of the Petroleum and Gas members at St. Louis, and of the Institute of Metals Division in Columbus, Ohio, have all been described in full in the magazine.

Jan 1, 1925

By David Donoghue

Efforts made in the year 1930 and in previous years restricted production in most of the fields of Texas to a point that was satisfactory, at the beginning of 1931, to the majority of producers and buyers. In the Panhandle, North Texas and West Central Texas districts, a few operators with refinery affiliations or contracts either ignored, or by virtue of injunction suits, did not comply with the Railroad Commission's orders, and there was some oil sold at less than posted prices, which, with the Oklahoma City difficulties, caused the first general price reduction. More could have been done perhaps to help the situation on the Gulf Coast and in the Laredo district, but natural advantages are not readily surrendered. East Texas Proration troubles in 1930 were insignificant when compared with those of 1931. In January, 1931, efforts were begun to convince the producers and citizens of East Texas of the necessity of curtailment. Opposition quickly developed and meetings were held in the towns of the region and proration denounced vigorously. Notwithstanding a strenuous campaign for additional legislation waged by many producers, the regular session of the State Legislature refused to strengthen the conservation laws and passed only the Marginal Well Bill, designed to prevent the Commission from prorating small wells. The Railroad Commission held a heated hearing on East Texas in the latter part of March. During April the Commission issued three orders based on the Yates plan for the proration of the East Texas field. Each succeeding order raised the allowable for the field. In June the opposition held more mass meetings at which a plan based on acreage was endorsed. Apparently on the theory that any plan was better than none, the Commission issued an order on July 2 embodying some of the features of the proposed plan, limiting production to 250,000 bbl. per day, and dividing the producing area into 20-acre units participating equally in the outlet. Owing to the bringing in of many wells and the many violators of the Commission's orders, production increased to such an extent that prices went as low as 5c per barrel.

Jan 1, 1932

By R. V. Whetsel, V. R. Garrias

The present study is intended as a preliminary statistical survey of the world's production of petroleum substitutes. The information presented is admittedly deficient. It is believed, however, that the increasing importance of these substitutes, particularly with Europe at war, justifies its presentation at this time, if for no other Table i.—Petroleum Subsiitues From Natural Gas Prom Coal Methane Liquid gas Liquid gas _ Manufactured gas Natural gasoline Gasoline Methyl alcohol Benzol Lubricants Etc. reason than to encourage enlightened pertinent discussion. The world's production in 1939 of petroleum substitutes—of which approxi-mately 97 per cent are direct substitutes for motor fuels—is tentatively estimated at 108,ooo,ooo bbl., or equivalent to the combined output of crude oil in 1939 of Rumania, Mexico and Colombia. With few exceptions, these figures of production represent also actual figures of consumption. The United States, owing mainly to its output of natural gasoline, leads all countries in the production of these products, with about 53 per cent of the total. In European countries, particularly Germany, the imminence of war in 1939 forced an increase in production and im- provement of methods of manufacturing motor fuels, largely from coal, with the result that this country produced in that year over 20,000,000 bbl. of substitutes. Since the beginning of hostilities, substitutes have offered more and more the means of meeting the unfavorable balance between supply and demand in European tes and Their Source Malerial From Oil From Molasses. Wood Shales Potatoes, Molasses.etc. From wood Shale oil Ethyl alcohol Producer gas Gasoline Methyl alcohol Gas oil Lubricants Etc. countries; the increase in production of these products being at least in part offset by the systematic bombing of synthetic plants and oil storage. The source materials and the resulting substitutes are listed in Table I. The following are the approximate gross heat equivalents of some substitutes to barrels of gasoline:

Jan 1, 1941

By William Metcalf

One of the first questions that naturally occurs to one who handles steel is, " Why does steel harden?" To answer this question the chemist and physicist have devoted much thought and experiment, and while they have enriched our store of knowledge of the nature and composition of steel, it cannot be said that they have yet solved the problem involved in its hardening. In this communication I desire to direct attention to a line of investigation yet new, in the hope that it may receive the attention. of those who have the time and ability to pursue it. I refer to magnetism. There are so many parallels between the action of magnetism on iron and steel and their behavior under different processes of manipulation that it would seem. as if there must be some connection between tile forces at work in the different cases, if, indeed, there be not an identify of force in all of these cases. Magnetism, as me know it, may be merely the visible manifestation of forces, which may serve as a guide to lead us to an exact knowledge of the structure, tile strains, and the resistances with which me have to deal in iron and steel. If a magnet be brought close to a pile of iron filings, the little pieces of iron will fly to the maguet and attach themselves to it, with their longer axes lying in the direction of the force. If molten cast iron be poured into an iron mould,—a chill,—the iron upon crystallizing will form needlelike crystals, with their long axes normal to the surfaces of the mould. • If the iron is at the proper temperatare and the quantity small, compared to the mass of the mould, the whole of it, will be chilled, or set, in 'the hard needlelike crystals

Jan 1, 1881

By Herbert Wilson

THIS topic was discussed at the meeting in St. Louis in September, 1917, and at the meeting in New York in February last, but in the interval the war has accentuated in measurable degree the necessity for considering human relationship, not only as between nations, or in the treatment of our returning soldiers, but with respect to the relations between labor and capital in industry. It is my firm conviction that no other subject will have so large a place in industrial and political life during the next decade as this. Heretofore, the employer has been so engrossed with the financial, mechanical, and technical aspects of his business that he, has been willing to muddle through 'his relations with labor as best lie might and, on the other hand, the laborer has been so engrossed in his endeavors to secure a livelihood under whatever living and working conditions might be offered him that he has given little thought to his relations to his employer, until some misunderstanding has ended in disagreement and strike. No thinking man doubts that were the machinery available for friendly, personal, face-to-face consideration of the problems confronting employer and employee, there would he fewer disagreements, fewer strikes, and a better and more settled industrial situation. The necessity for some such medium for exchange of views has resulted in the organization of labor and, in some measure, of capital. Each party, engrossed only in defending its own viewpoint, has generally tried to gain its point by might rather than by right. Gradually, however, the representatives of both elements are beginning to appreciate that when the machinery for bringing them together in friendly communion is available their differences frequently settle themselves. There remain yet vast numbers of employers and of employees who are not organized and to whom the opportunity of friendly discussion of differences is not available; for these the machinery should he provided.

Jan 1, 1919

By E. E. Brownson

THIS paper will be confined to the treatment of methods as applied in the laboratory of the Boston and Montana Reduction Department of the Anaconda Copper Mining Co. at Great Falls, Mont. As the electrolytic plant of this company operates at a current density of approximately 35 to 40 amperes per square foot when running up to capacity, the arsenic and antimony content of the anodes delivered to the, plant is of considerable importance as bearing on the purity of the refined cathodes turned out. Owing to the rather high relative percentage of antimony, it has always been the custom to determine antimony as well as arsenic in all forms of copper. Thus, anodes have been analyzed in which the antimony was about equal to the arsenic although the average shows about 2 parts of arsenic to 1 of antimony. In the refined copper the relative proportions of the two impurities vary considerably, but probably in the average are about equal. In this latter case, the percentage of the two is so small that ordinarily no attempt is made to separate them, the report of analysis showing percentage of As and Sb combined. Although rapid and exceedingly accurate determinations of arsenic may be made by means of various distillation schemes, the determination of antimony, either by itself or together with arsenic, has always been more or less cumbersome and has required a considerable amount of time. By the methods, details of which follow, the determination of arsenic and antimony, either separated as in the case of anodes or together in case of refined copper, is accomplished in 24 hr. from the time the sample is received by the chemist.

Jan 8, 1913

By M. K. Barnett

[ ] ENGINEERING research consists, broadly speaking, in the investigation of the effect of the variations in a number of factors on some property of a product or characteristic of a process. The unambiguous description of the product or process requires that the property or characteristic be expressible in quantitative terms. For the purpose of practical control, it is likewise desirable that the independently variable factors governing the product or process be quantities, although this ideal goal is not always attained. Maximum efficiency-i.e., the attainment of the maximum amount of reliable, useful information relating to the influence of the factors on the property of the product or characteristic of the process, for the least expense-is an important requirement for the satisfactory operation of a research organization. Obviously, a necessary condition for the attainment of maximum efficiency is an adequate knowledge of the specialized field in which the experimental research lies. While necessary, this condition is not sufficient. Proper attention must also be given to the general principles of experimental design together with the modem methods for the analysis and evaluation of experimental data. The present discussion is confined to a single design, the so-called "factorial" design. This design is of special interest in that it attains its goal, maximum efficiency, by directly departing from the

Jan 1, 1947

By H. M. Howe

One of the little electric-resistance magnesia crucible-furnaces which I designed for the metallurgical laboratory of the School of Mines of Columbia University is shown, in vertical section, of full natural size, in Fig. 1. The furnace itself consists of two semi-cylinders of magnesia, A A, with a cover of magnesia, B B, and a stopper, C, also of magnesia, which is perforated to admit the leads x, y, of a thermo-electric couple. The furnace is heated by the spiral of platinum wire, D D (entering and departing by the openings I and K), through which a current of any desired strength is passed, bringing it to incandescence, and to ally temperature, not above the melting-point of platinum, which may be desired. The crucible E, actually used in this furnace, is also of magnesia. I have heard of some unsuccessful attempts with furuaces of this general class, and have attributed these failures to the use of siliceous materials for the furnace-walls. Of course such a result is what we should expect, since the silica mould readily be electrolysed by the current, and the resultant silicon would alloy with platinum ; but the little magnesia furnace here clescribed seems to be wholly free from this objection. It has been used in my laboratory for some months, and temperatures, up to 1100° C, hare been developed in it over considerable periods of time—indeed, it has been held near 1400" C. for about two hours—without indication, thus far, of any deterioration of the platinum. In the section shown, F F are a pair of steel disks, bound together, but separated by the inverted thermo-junction, N, of the thermo-electric pyrometer. This arrangement permits the observation and record of retardations in the heating and cooling of F F—in other words, the determinations of the cooling curves of steel—a purpose for which the furnace has been used, thus far, more frequently than in the determination of meltingpoints. For the latter operation, however, it is also suitable.

Jan 1, 1902

By Albert Walcott

THE success of various operations in the manufacture of optical glass depends, in a large measure, on the ability to maintain proper heat control. A good pyrometer system is, therefore, a very necessary part of the equipment needed. Men of long experience in dealing with high temperatures, who have acquired through constant practice the ability of judging approximate temperatures by means of color, are undoubtedly valuable, but even the most competent are not as reliable as a good pyrometer system. They admit that their ability to judge accurately varies from day to day and that their judgment is affected considerably by the condition of the sky, whether it is clear or cloudy. Besides, where it is a matter of only a few weeks to train a man to operate a pyrometer system, it takes about as many years to train him to judge temperatures by the state of incandescence. The pyrometer outfit in use in the glass plant of the Bausch & Lomb Optical Co. consists of the following: Platinum elements, optical pyrometers; base-metal elements, indicators, potentiometers, and recording pyrometers. Platinum Elements and Optical Pyrometers.-Temperature control in - the melting operation is of such great importance that it is very desirable to know the exact temperatures, relative temperatures being of little value. The use of the platinum element is to determine the rate of heating or cooling of the furnace. The platinum couple is installed in either the crown or the wall of the furnace. It is placed first in a porcelain protecting tube and this is placed in a permanently fixed fireclay tube projecting from 1 1/2 to 2 in. into the fire-chamber. It has been found impractical to use the platinum couple for determining exact temperatures of the melting furnace, for the platinum element deteriorates rather rapidly at the high temperatures used, 2500° to 2700° F. (1371° to 1482° C.). When protected and installed as described, though,

Jan 9, 1919

By F. W. Gordon

Since the waste gases of the blast-furnace came to be generally utilized in heating the blast and raising steam, the gradual improvement in the economy of fuel, mainly through the nse of higher temperature in the blast, has impoverished the gases. The increased output per unit of measurement of the furnace, and the increased height of the furnace, have markedly increased the resistance to the blast, thus enormously increasing the duty required from the gases. In other words, a gas reduced in heating power by a further dilution of CO, is required to raise the temperature of the blast to 1800' Fahr., where formerly 600' was a good temperature, and at the same time to raise steam enough to drive the air into the furnace at a pressure of from four to eight pounds in coke practice, and from eight to twelve pounds in anthracite practice, and also pump at least double the water formerly used at furnaces. Hence the necessity for the employment of the best scheme for thoroughly consuming these gases with the least dilution of air, and the use of the best device for absorbing the heat prodnced for the purposes above mentioned. In a former paper before this Society the writer called attention to such improvements as had been made by his firm, by which it was claimed 1400' Fahr. could be maintained in the blast by a less consumption of gas than was required to maintain 900' when using pipe-ovens; and it would not be too much to say that 1600' Fahr. might now be written in place of the 1-400. The object of this paper is to give the practice of our firm in the

Jan 1, 1884

By John Henry Harden

It appears that in the earlier days of anthracite coal mining, 1824-25, the Lehigh region mined 76 per cent. of all the coal sent to market. During the same period Wyoming sent 12 and 5 per cent. respectively, whilst the Schuylkill sent 11 and 18 per cent., the number of tons marketed being in those days very small indeed. In the year 1828 the Schuylkill region mined over one-half of all the coal sent to market, and continued to do so for thirty years (with the exception of the year 1831), until 1858 ; since that date the production has declined very steadily in comparison with the other regions, until, in 1876, it was only 34 per cent. Wyoming, in the year 1820, was mining 40 per cent., but the production of all the regions was very small; in six years it declined to 5 per cent., increased to 34 per cent. in 1831, declined to 10 per cent. in 1838. Since which time the increase has been gradual, until 1873-75 Wyoming produced over 50 per cent. of all the anthracite coal sent to market. In 1867 the production exceeded that of Schuylkill, and has continued to do so since that time. In the year 1876, during the existence of the "coal combination," Wyoming lost 9 per cent.; during the same time Lehigh gained 7 and Schuylkill 2 per cent. over their relative production of the preceding year, the decrease of Wyoming being two and a half million tons, the increase of the Lehigh one million, the decrease of the Schuylkill nearly three-quarters of a million. The extraordinary production of the Lehigh region at a time of decreased demand and in opposition to an agreement with the other regions to limit the supply to the supposed demand mas the cause of the disagreement which ultimately broke up the combination of the great coal-producing and carrying companies. The Lehigh region produced very steadily, from 1829 to 1854, an average of about 22 per cent. of the whole production. From 1854

By G. Sachs, G. Espey

SIMPLE methods can be used for the determination of the residual stresses in thin-walled tubing if the stresses consist of high tensile stresses at the one surface and high compressive stresses at the other surface Such a stress distribution is approximated in sunk tubing and in deep-drawn shells It is possible to cut sections from such articles in such a manner that a major part of the residual stress is relieved by a bending of the part that is separated from the adjacent metal The circumferential stress is evaluated from the change in diameter D, occurring on splitting a length of tubing (Fig Ib),1-5 or from deflection resulting from the cutting out of a circumferential tongue (Fig Ia) G The bending moment M released by such a flexure is [ ] The release of this bending moment corresponds to the release of stresses, which, in a thin section, vary linearly from one surface to the other, and have the following value in a particular fiber a certain distance (zx from the surface [ ] where C is the section modulus and d is the thickness of the section, the ratio AI C being d 2 for a rectangular section* The maximum stress values at the surfaces are [ ] For most purposes the simpler equations [ ] will be satisfactory, where Dm is the average of the mean diameters of the tubing

Jan 1, 1941

By David C. Grant, Erich W. Tiepel

In situ mining is a process for recovering uranium from relatively small or low grade ore bodies. The process involves passing a lixiviant and oxidant, typically NH4HC03 and H202, through a uraniumcontaining ore body. As the solution progresses through the ore body, the uranium is oxidized from the plus four to the soluble plus six state. The bicarbonate complexed uranium laden solution is removed from the ore body and the uranium recovered in an above-ground processing plant. During the leach process lixiviant cations may be sorbed on the ore host, if the host contains exchangeable clay minerals. This report examines the implications of this clay interaction on ground-water quality, the various available in situ mining restoration methods, laboratory procedures for simulation and development of those methods, and the results of using the restoration methods in the field. Various restoration methods, including ground-water sweeping, clean water recycle, and chemical restoration are presented and discussed. The use of ore characterization, agitation leach tests, and column tests to study cation sorption and desorption, and thus, to identify and evaluate restoration methods is discussed. Ore characteristics identify the clay type and clay content, which allows the estimation of the magnitude of the cation sorption by that ore. The chemical effects of clay exchange and of chemical restoration can be examined using agitation leach experiments and packed ore column tests which also provide information on the physical effects. The agitation leach test is a relatively rapid means of determining the sorption and desorption characteristics of an ore. Unlike agitation leach tests, column tests can be used to assess the influence of solutions on permeability, on precipitation problems, and on other chemical changes. The effectiveness of using restoration methods, which were developed and tested in the laboratory, are examined by presenting field restoration data from several mining sites.

Jan 1, 1979

By J. R. McWilliams

THE task of recovering most of the contents of an oil and gas reservoir economically presents many and varied problems. In order to attempt intelligently a solution to these problems, an understanding of fundamental physical laws is essential. As the pertinent facts needed in applying these laws to recovery problems are not readily obtainable, observation must be made and the data tabulated. Here, good judgment must be exercised, for at best the information is meager. The engineer is well fitted to undertake the task of solving this problem. In my opinion, the decision on the part of some production executives to allow the engineer to cope with the oil recovery situation and other problems, is an outstanding example of improvement in production methods. The executive head must make this decision or the qualified engineer will be working under a severe handicap with the present system of supervising the production of oil and gas. A qualified engineer should have not only the required technical training but also enough field experience to enable him to understand the difficulties encountered in producing oil and gas. Such a man tactfully cooperating with the practical oil man can greatly improve present methods of oil recovery. The realization that nature's forces have not been efficiently controlled in past recovery of petroleum deposits has recently brought distinct improvement in production methods. Papers are to be presented at this meeting discussing in detail improved methods of conserving gas in both flowing and pumping wells, and also methods of lifting oil after Nature's supply of gas has proved inadequate. The application of back pressure to producing oil wells has not, to my knowledge, been extensively applied in Oklahoma or Kansas up to the present time. Most of the flowing wells are allowed to flow through the casing until the rock pressure has been dissipated. However, some flowing wells have been tubed before the well stopped flowing through the casing. Recording pressure-gages can be installed to study well performance.

Jan 11, 1926

By Hon. Charles McCrea

MINING taxation is a subject which bears definitely upon-the welfare of the mining indus-try. Every government must have a revenue but that revenue should be raised in such a way as to hamper as little as possible legitimate enterprise or industry. A mining tax should be fair, and one which appeals to the natural sense of justice. Our present system is a tax on net- profits after all expenses are met. On profits in excess of $10,000 the Mining Tax Act takes three per cent., one-half of which goes to the Govern-ment and one-half to the municipality in which the mines are situated, to meet local needs for roads, schools, etc. On profits from one to five million dollars", the tax is five per cent.; over five million, six per cent., and so on. The first $10,000 profit is exempt. The result is that if a mine is worked at a loss, it pays no tax at all; if it makes a small profit, it pays a small tax; if profits are large, the tax increases accordingly. It is difficult to imagine a fairer or less onerous method of taxation, or one better adapted to meet fluctuating conditions from year to year as profits rise or fall. A just and fair tax should be levied on profits, never on capital. There is, one branch of the mining industry upon which is levied a higher tax than upon other branches, namely, the nickel industry. I see no good reason why any branch of the mining industry should be discrim-inated against on a profits tax basis. A mining tax should not discourage development. The present tax meets this requirement. In the early years of a mine, when it is all outgo and no income, the mine pays no tax. Not until it reaches a productive and. profitable stage does the tax take effect, and then the mine can afford to pay it. Further, a tax on profits does not operate against the opening up of low-grade deposits, or those in which the chance of success is to a certain extent speculative.

Jan 10, 1923

By Merrill Horine

IT has been stated and accepted for many years that the automotive industry was the instigator, the principal sponsor for and the largest user of alloy steel and nonferrous alloys. The only universally recognized standard specifications and heat-treatments for these materials are those adopted by the Society of Automotive Engineers. It is this same auto-motive industry that has been the chief inspiration for and consumer of modern production machine tools. The production curve of steel ingots is more sensitive to fluctuations in automotive production than any other influence or group of influences. In every other important steel-con-suming industry, automotive materials and automotive processes are the outstanding features of modern progress. In this connection I need only mention the prefabrication of buildings, following the automotive system of straight-line, interchangeable mass production; the motorization of ships and railroads, employing automotive types of prime movers; the production of pressed-steel stoves, plumbing and furniture by methods originated in the automobile-body industry and the extensive use of rubber for the cushioning of all manner of machinery as pioneered by the automotive and tire industries. Dr. Jeffries has brought out this point in his address (p. 21), assuring us that the transportation industry is the largest user of these materials. In the transportation industry, or as we might more accurately express it, the transportation group of industries, the. automotive industry pre-dominates as a user of light alloys. One out of every four tons of aluminum produced is consumed by the automotive industry. Similarly, the automotive industry ranks first in the consumption of the following metallurgical materials: steel, 24.04 per cent; malleable iron, .57; alloy steels, 72.2; nickel, 30; lead, 39 per cent.

Jan 1, 1936

By Bernard Rachlin

IN the mineral industry measurement of density or specific gravity of slurries is often necessary or highly desirable. To date the most successful method of measuring the specific gravity of various media is to hand weigh a constant volume sample of the slurry. This method is time-consuming, however, and is intermittent rather than continuous. Most density measuring instruments in use today are variations of three basic systems: air bubble tube systems, radioactive methods, and displacer systems. The high cost of the radioactive cell, combined with the precision electronic measuring that is required, limits the practical utility of this procedure to a small percentage of critical processes. In the air bubble systems clogging of the bubble tubes with solids has rendered this type of measurement completely ineffectual for many applications. Continuous or intermittent purging of the bubble tubes with air or water to prevent tube clogging has been tried but has not been very successful, especially in the heavy media process. The displacer system, which presents the fewest complications of all the density measuring systems, consists only of a metal immersion unit and a means of weighing it. In the past, settling of the solid in the slurry has caused untrue samples and clogging of the media at the bottom of the chamber. It is also important to dampen excessive flow surges such as those caused by reciprocating pumps. The system described here successfully overcomes these difficulties. Description of the Process System: The process equipment, on which the field tests were run, was a

Jan 1, 1957

By Frederick G. Bulkley

That portion of the geological structure of the Leadville district which rests upon the Archæan is made up of sedimentary beds of Silurian and Carboniferous formation, consisting of many conformable strata of limestones, quartzites, and shales, which have a total present thickness of about five thousand feet. Interbedded with these strata are found, under somewhat fixed lams of regularity, sheets of intrusive igneous rock,' varying in thickness from a foot or two to several hundred feet. These consist for the most part of various types of felsite rocks, classed, by the sanction of common and long-continued usage, under the general term of porphyries. Mr. S. F. Emmons, in the abstract of his " Report upon the Geology and Mining Industry of Leadville," says in this connection : In their mode of occurrence the type-feature is that of intrusive masses, which are developed on a scale of unprecedented magnitude, and follow certain horizons with remarkable regularity.... It is probable that this mode of occurrence of eruptive rocks, viz., as intrusive masses which originally did not reach the surface but were forced up to a certain horizon and then spread out bettween the beds, is far more common than has hitherto been suspected by geologists. It is difficult to conceive of the conditions under which a fused mass could pry open strata to a width of one thousand feet or more, overcoming the weight often thousand feet of superincumbent rocks, and spread itself out in a continuous sheet between the beds to a distance of ten miles beyond the point or line of eruption. That they did exist, however, can be clearly demonstrated in this region.... In one single section over fifteen sheets, many several hundred feet thick, were counted between the Blue Limestone and the top of the Carboniferous. The region here under discussion is made up of a series of great

Jan 1, 1885