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By T. Egleston

circumstances, would prefer the steel with which they are now familiar, to a specimen that Mr. Sandberg has described as having broken into seventeen pieces under the wheels. After blowing such low manganese steel, it may be coaxed into a rail, but it is a wonder that it holds together so long as it does, with so great a nornber of minute flaws. I would not in any way depreciate chemistry, but I think it should be kept in its proper sphere. Let the chemist look after the quality of pig metal, and apply common sense in the avoiding of extremes, then the most fastidious railroad cannot find fault with the result. PROFESSOR EGLESTON, New YORK City : It is not my place as an engineer to apologize for the chemists, but as no one seems disposed to do so, and as they have had more than their share of criticism, 1 am glad to say that I believe there are chemists in this Institute whose work and word are just as reliable, arid perhaps even more so, than that of the average engineer. But we ought to make a distinction; there are chemists and chemists. With the ordinary commercial chemist, who looks upon the science as so much merohandise, I have not a particle of sympathy; but with the chemist who looks upon his profession as engineers do upon theirs, I have every sympathy. When matiufactorers and engineers go to a chemist and ask him to make an investigation, and scretv him dowu to the lowest point, turning the equivalent of his brains into cents and mills, they ustially get an exact equivalent in poor work for miserable pay, and no one has or should have any sympathy with them, and the under these conditions has no right to ask for any, and no reason to criticise any work that he may get under such circumstances. But I am disposed to think that the chemists who have been replwented and discussed at this meeting do their work conscientiously, and that it is as reliable as that of almost any profession. I believe, however, that this problem of steel rails is being investigated in a wrong direction. I said so at the Pittsburgh meeting, and I think the discussion of this meeting will prove it to all those who have heard it. I think the chemigt is incapable of solving this problem unlees he goes very far into the domain of physical chemistry, so far that it becomes physics and not chemistry; and that the physicist will be the one on whom we must rely in the future for the elucidation of the subject. The chemist may aid the physicist, but it is my decided opinion that we are looking in the wrong place to get the explanation of the phenomena.

Jan 1, 1881

By Harlan W. Nelson, James B. Purdy

The great majority of stokers used in residential heating installations are of the clinkering type. Because of inherent characteristics of the underfeed combustion process as it occurs in these small stokers, and because of the wide range of operating conditions encountered in residential heating schedules, not all bituminous coals can be used successfully in residential underfeed units. The problem of providing consumer satisfaction has been attacked by the joint efforts of the stoker manufacturers and the coal industry; the stoker manufacturers have been concerned with improving their product to permit the use of a wider range of coals, and coal operators have made every effort to market selected and better prepared coals. In view of the wide range of physical characteristics and chemical properties of bituminous coals, the problems are real and are receiving increased attention. Some twelve years ago a laboratory method was developed at Battelle Memorial Institute for the relative evaluation of coals for use in residential underfeed stokers. The method was developed in conjunction with work being done at that time for Bituminous Coal Research, Inc., and for individual coal producers, to obtain information on the characteristics of coal that determined the successful performance of the small stoker. Details of the equipment and test procedure were given by R. A. Sherman1 in a paper presented at the University of Illinois Fifth Short Course in Coal Utilization. During the past several years, the evaluation of over forty different coals has been determined by investigations sponsored at Battelle by coal operators in the eastern producing districts. The purpose of this paper is to compare the results and conclusions derived from the various tests with marketing experiences of the operators, and to discuss briefly the relationship of test results to standard laboratory determinations. Equipment Used in Tests Fig 1 shows schematically the equipment used in the evaluation tests. The stoker is a commercial model of conventional design, having a nominal feed rate of 30 Ib per hr. A special laboratory furnace is used, which is tightly sealed to prevent the entrance of secondary air. The complete stoker-furnace assembly is mounted on platform scales which permits the measurement of combustible weight losses occurring during the test. The furnace stack, in which are a thermocouple, flue-gas sampling tube, and smoke meter, is connected to the laboratory exhaust breeching through a friction-less connection. Through use of an auxiliary blower system, provision is made for the measurement of the air delivered by the stoker fan to the windbox. A water seal in the duct work eliminates inter-

Jan 1, 1950

By Joseph F. Shirley

A froth flotation plant to recover byproduct molybdenite must be designed specifically for the selected separation process and the type of ore being treated. However, some general rules concerning byproduct molybdenite plant design can be suggested that would be valid for most processes. The term byproduct molybdenite in this paper is limited to the recovery of molybdenite from copper porphyry ores, which essentially amounts to selectively separating molybdenite from copper and iron sulfide concentrates. In addition, most of the discussions would apply only to the almost universally used approach of floating the molybdenite and depressing the copper and iron sulfide minerals. Thickener It is considered essential that the feed to a byproduct molybdenite plant be thickened prior to being treated for molybdenite recovery for the following reasons: 1) Thickening allows the rougher and any preconditioning stages to be operated consistently at the optimum percent solids. 2) Generally, the size of equipment used for pretreatment and the rougher flotation is considerably smaller and less expensive than if the copper flotation concentrates were treated directly. 3) The removal of as much water as practical by thickening removes flotation reagents added in the copper flotation circuit, especially frother which can be quite troublesome in a byproduct molybdenite plant. Although thickening of the molybdenite plant feed has long been recognized as necessary to optimum metallurigcal results, very often this area has been designed poorly. The thickener should be sized so that it can produce a consistent thickened product containing 60 to 65% solids without the use of flocculants. Some plants are only able to thicken to 45 to 50% solids consistently while other plants let the percent solids vary from 45 to 60% over a 24-hr period. While the former is more desirable than the latter, in many cases better metallurgical results could be obtained if the percent solids could be held consistently close to 60%. Probably the simplest and most satisfactory system of handling the thickener underflow is to spigot it into a sump, using a sphincter type valve for the orifice, controlled by a density meter. Another satisfactory approach is to use an ODS type pump to meter the underflow. There are other methods of handling thickener underflow which work satisfactorily as long as the amount of copper concentrates entering the thickener is relatively uniform. However, they often fail to operate satisfactorily when there are large fluctuations in the thickener feed rate due to fluctuations in ore tonnage and/or copper grade. If the percent solids in the plant feed could be held close to 65%. There is the possibility the molybdenite plant tailing would not have to be thickened prior to the copper filter plant. This means that the molybdenite rougher float would have to be conducted at 45 to 50% solids with all the cleaner tailings returned to the rougher for dilution. Admittedly, in some situations this approach would be impossible, but if capital or plant area is limited, it should be considered.

Jan 1, 1981

H. H. Campbell, Steelton, Pa. (communication to the Secretary) : I wish to thank Mr. Webster for the copious quotations he has made from my writings, as he has given nearly all the arguments I wish to advance. It is necessary to note, however, his statement that most of his experiments were made on universal-mill plates, and that these were not subject to my condemnation of irregularity. I think this is a mistake. It is well known that universal-mill plates are finished under very different conditions of temperature, with the express purpose of regulating the tensile strength. This is a perfectly legitimate practice; but it renders almost worthless any calculations on the relations of the chemical and physical equations when the influence of such finishing is omitted. Another important point Mr. Webster has not answered at all. I have shown by an excerpt from his own table that two entirely different formulæ may be constructed; and it is undeniable that one is as valid as the other, since Mr. Webster started with no premise at all save an assumption that the effect of carbon was constant. This was an assumption pure and simple, and hence has no special virtue. The whole result of Mr. Webster's investigation is not that the effect of carbon is a constant, and that those of phosphorus and manganese are variables. On the contrary, there are two answers, with nothing to show which is right. We learn that if carbon is a constant, then phosphorus and manganese are variables; but that if phosphorus and manganese are constants, then carbon is a variable. This is a distinct advance over complete ignorance, but it is not final and satisfactory from either a mathematical or metallurgical standpoint. Regarding my own formulæ, I would say that they are used regularly in the testing-laboratories of the Pennsylvania Steel Company. The tensile strength of every heat is calculated

Jan 1, 1899

William H. Blauvelt, Syracuse, N. Y.:—Is the coal itself from which the briquettes are made of good quality for steam-ing-purposes? Mr. Parker :—It is an anthracite coal mined near Bank-head arid used on the Canadian Pacific railroad. It contains about 83 of carbon, 8 of ash, and 8 per cent. of volatile material. With regard to briquetting of a mixture of fine coal and coke-dust, I understand that a plant has been installed near Detroit in which coke is mixed with anthracite; also the plant of the United Gas Improvement Co. near Philadelphia is briquetting a mixture of anthracite coal, the resultant briquettes being used in the gas-retorts. Mr. Blauvelt:—The purpose of the Detroit briquette-plant of the Solvay Process Co. has been partly to use up the coke-breeze from the by-product ovens and partly to utilize the pitch. There is no necessity for mixing anthracite with the coke-breeze, but the supply of breeze is limited, and anthracite

Jan 1, 1909

At a time when Congressional stiffening of health and safety regulations in the nation's coal mines seems all but an afterthought, when the problems confronting both mine operator and worker are being tossed about like a pigskin in an Australian- rules football match, what could be more appropriate to the times than to incorporate a discussion on these matters into the proceedings of an annual coal meeting. Integration of both technical and topical discussion provided the strength for this 28th Annual Meeting of the Central Appalachian Section of the AIME, convened at the The Greenbrier, White. Sulphur Springs. W. Va., Oct. 31-Nov. 1. Three technical sessions prepared for the occasion were served to those in attendance. First of these was held on Friday morning. Rendered excellent coverage, topics included Roof Structure Analysis at Blacksville No. I, presented by David Eyer, Christopher Coal Co.; Methane Monitors (evolution and evaluation of present day detection equipment); and Instantaneous Control Reaction to Mine Fires and Explosions, in which Elmer A. Fike illustrated the point quite vividly by showing a film on the potential of such control equipment. Indeed, the ability to snuff out a mine fire before it is allowed to spread even beyond its own igniting sparks speaks very well for itself. However, Fike hastened to point out that certain difficulties had to be overcome before these "fire watchers" could be implemented successfully in mines. These "bugs," inherent in virtually all coal mining environments, include ignition of sulfur pockets on mine facings and delivery of sparks on trolley rails, both of which may impede the accuracy of such control monitors.

Jan 12, 1969

By Robert M. Asimow, Bisuddhi Riddhagni

THE use of back-reflection Laue photographs for crystal orientation is standard in many research projects. The time required for the orientation of any given crystal depends largely on luck and the skill of the investigator. In any case, where large numbers of crystals are used, this time can be quite considerable when the standard methods involving a Greninger chart and Wulff net are employed. For this reason the technique described below was developed. This new procedure applicable for cubic crystals (without preparation of new charts) largely eliminates the skill and luck factors and makes possible the determination of orientation in minutes. The procedure works in the following way: the Laue photograph is examined and arbitrarily an important hyperbola is picked out. An important hyperbola is defined as one which contains some spots through which several hyperbolas pass. Such a hyperbola inevitably corresponds to a low-index zone axis. The angles between the reflection planes causing all the spots on this hyperbola can be read directly from a Greninger chart in the usual manner. If the hyperbola contains more than five spots, these interplanar angles will positively identify the zone axis and the indices of each of the reflecting planes. However, initially since neither the zone axis nor the Miller indices of a diffraction spot are known, there are a very large number of possibilities that must be considered. Using tables of interplanar angles to check out every possibility would be quite tedious, so that this approach is not generally used. Instead, various poles are plotted on a stereographic projection. In the cubic system, however, it is possible to plot out once and for all the angles between all planes of a particular zone axis up to some upper limit of Miller indices. This has been done for all low-index zone axes in Fig. 1. Given these charts, it is quite a simple matter to identify the spots of the unknown hyperbola. All that is necessary is to plot the angles read off the Greninger chart to the same scale as Fig. l(b) on a strip of paper. Then this strip can be slid along each zone axis of Fig. l(a) until a good fit is obtained. Once this is accomplished, the Miller indices of each spot are given and thus the orientation problem is solved. To check, it is possible to pick a second hyperbola and see whether a compatible solution is obtained. This is most conveniently done by picking for the second hyperbola one that contains a spot common with the first. If the specimen axis is chosen parallel to the incident X-ray beam, then usually the [ loo] hyperbola will appear on the film as one of the more important hyperbolas and consequently will be either chosen initially or as a check. Using the [100] hyperbola, after the (001) or (011) spots have been identified, the latitude and longitude of the specimen axis can be read directly from the Greninger chart so that it is unnecessary to use a Wulff net for the entire orientation procedure. This makes the operation not only quicker but more accurate. Of course, if neither the first nor second hyperbolas correspond to [loo] then a third hyperbola can be chosen.

Jan 1, 1967

Meeting of Mar. 27, 1914.-President Thayer announced the appointment of H. S. Munroe as a member and E. Gybbon Spilsbury as Chairman of the Library Committee of the Institute. The President announced the appointment of the Committee on Papers and Publications, the Technical Committees, the Committee on Increase of Membership, and the Committee on Junior Members and Affiliated Student Societies. The President announced the appointment of Dr. George F. Kunz as a member of the Reception Committee of the International Engineering Congress, 1915. It was voted that the Institute accept the invitation of the Mining and Scientific Press to occupy space at the Panama-Pacific Exposition next to them and avail itself of the service of their representative to receive and register members of the Institute who visit this space during the exposition.

Jan 5, 1914

By K. L. Sehgal

Minerals are the basis of modern civilization: their exploitation and effective utilization are a yard- stick for measuring the comparative prosperity of different nations. This is particularly true in India where industrialization is just beginning to pick up speed. Production targets for our Fourth Five Year Plan (1966-71) are far ahead of the figures for, say, 1950 (the year we won independence) and show the extent of the expansion. Many problems remain to be solved, not least of which is the shortage of raw materials. India is no novice at utilizing minerals. Archaeological ruins at Harappa and at other historical places in the country show evidence of the fact that the ancient Indians not only knew the art of winning minerals from the ground over 6000 years ago-they were also well acquainted with metallurgy. Some of the present sites of mineral exploitation are the same as those our ancestors worked for many centuries.

Jan 9, 1965

THE following employment items are made available to AWE a non-profit basis by the Engineering Societies Personnel Service, Inc., operating in cooperation with the Four Founder Societies. Local offices of the Personnel Service are at 8 W. 40th St., New York 18; 100 Farnsworth Ave., Detroit; 57 Post St., San Francisco; 84 E. Randolph St., Chicago 1. Applicants should address. all mail to the proper key numbers in care of the New York Office and include 6c in stamps for forwarding and returning application. The applicant agrees, if placed in a position by means of the Service, to pay the placement fee listed by the Service. AIME members may secure a weekly bulletin of, positions available for $3.50 a quarter, $12 a year. MEN AVAILABLE Executive Engineer, Mining Engineer Graduate, 25 years' management experience from plant operation to vice president in charge of manufacturing for national concern. Management and operational experience in gypsum, asbestos, cement, paper, felt, asphalt products. West Coast or South location preferred. Prefer permanent position but would consider connection on consulting basis. M-663. Geologist and Engineer, E.M. (Geol.), Ph.D., 46, married, excellent health. Nineteen years' broad experience including appraisal, acquisition, large-scale exploration, special problems, planning, organization, and supervision in U.S., Africa, and South America. Sound approach and execution, writes clearly. Currently employed but available short notice. M-660. Mining Plant Designer. Over thirty years' broad mining experience. Graduate mining engineer, registered mechanical engineer, experienced structural engineer. Member AIME, NSPE. Fully experienced all phases design, from initial plant layout to final details. Excellent references. Presently employed but available reasonable notice. M-661-238-Chicago.

Jan 1, 1952

By J. W. Snavely

THE part that acceleration plays in starting a belt conveyor and its effect on belt conveyor design are well understood in a general way. Its practical importance is easily overlooked, however, and under some conditions, it is absolutely necessary to give the problem of acceleration detailed study. Most handbooks on conveyor belting design adequately present basic data for the determination of acceleration values. This paper will only attempt to present practical thinking and a convenient method of treatment of acceleration in belt conveyor design. Mathematical Analysis In working out the various problems of conveyor belt acceleration, the starting point, as presented by the handbooks, is the familiar formula of "force of acceleration is equal to the mass times acceleration." By expressing these fundamental quantities in terms of belt conveyor design, it is possible to arrive at the unsuspected conclusion that the acceleration time for horizontal belt conveyors is independent of the load, and instead, dependent upon the belt speed, the type of drive arrangement and drive pulley, and the idler coefficient of friction. The mathematics leading to this conclusion are shown in Table I, which has been prepared to show, this derivation. While at first the conclusion just given may not seem to be reasonable, further reflection indicates that obviously the type of drive pulley and the type of drive do affect materially the tension in the conveyor belt, and thus, as clearly shown, the time of acceleration is dependent upon the factors mentioned. Inasmuch as all of the factors except time are predetermined by the belt conveyor design, it becomes relatively easy to establish the accelerating time and to reduce further this time determination to a simple graph from which the time in seconds can be read directly. Such a graph is given in Fig. 1. The table appearing on Fig. 1 should be explained further. For a given belt speed, the time of acceleration can be expressed as a percentage of the belt speed. The time of acceleration is also dependent on the drive arrangement, and changes in the drive arrangement consequently change the time of acceleration. It further follows that for a given belt speed, the time expressed as a percentage of that belt speed also changes with the type of drive. Obviously then, it becomes possible to graph the percentage of speed for each type of drive against the belt speed and accelerating time, after which, for a given belt speed and type of drive, the time can be read directly in seconds. Two constants were established for Fig. 1, the first one being the limiting of the maximum acceleration tension to 35 pct of the full load operating tension in the belt. The purpose of this is to limit the total tension imposed upon the belt during the acceleration period to 135 pct of the full load operating tension, which is the amount required to start or breakaway the fully loaded belt conveyor from rest. The other constant is the friction factor used for the idler equipment, which has been established as 0.022. For installations where it is necessary to establish the values of acceleration, invariably high grade idler equipment is used, and it has been established from. field experience that 0.022 for the idler friction factor is amply conservative. The use of this friction factor for idlers must be tempered with judgment, of course, for occasions will arise where more power than indicated is required to start, even with the very best of equipment, such as low temperature operations that tend to congeal the grease in the bearings and thus produce additional friction drag. An inspection of the table in Fig. I affords a convenient rule of thumb method for determining the acceleration time, which conveniently can be 5 pct of the belt speed in seconds. The 5 pct of belt speed figure is close to the average for most types of drives. In using Fig. 1 it must be emphasized that it applies accurately to horizontal belt conveyors only.

Jan 1, 1952

By G. Austin Schroter, Ian Campbell

ALTHOUGH there is now an extensive literature on the bleaching clays, not a great deal of material is to be found concerning the geological features of these deposits and their bearing on problems of exploration and development. At the same time, chemical and crystallographic research on the clay minerals during the past few years has laid a suitable foundation upon which to base conclusions of economic value drawn from field observations. All of the criteria and deductions herein presented are based upon extensive field work by the senior author, both in the United States and Canada, and when subjected to the ultimate tests of development and exploitation they have held up remarkably well, despite the fact that many of these conclusions apparently have not been reviewed in the literature heretofore. The nomenclature of the bleaching clays is rather confusing in the light of present-day commercial standards and has even led to litigation." The old term "fuller's earth" is largely based upon trade usage and the definition of the term therefore is dependent upon the changing standards of commerce. For statistical purposes the Bureau of Mines81 classes as "fuller's earth" all natural bleaching or filtering claylike materials that possess high adsorptive capacity without previous chemical treatmerit or activation. Conversely, the so-called activated or acid activated clays are now generally recognized as any clay mineral or mixture of the clay minerals whose adsorptive capacity has been developed to commercial standards by chemical or physical treatment. Therefore, without attempting to propose any additions to the nomenclature of bleaching clays, this paper will refer to naturally adsorptive clays and activable clays, respectively, for the two types indicated.

Jan 1, 1940

By Frank Firmstone

In the Kaernthner Zeitschrift, No. 2, 1881, p. 53, et seq., Prof. Ledebur details some experiments on the power of various silicates of lime and alumina, magnesia and alumina, and lime, magnesia and alumina, to remove sulphur from pig-iron, from which it appears (as has long been recognized in practice) that the more basic the silicate the greater the quantity of sulphur it will take up; but also that for the same grade of silicate, this quantity is greatest for the lime-alumina silicate and least for the magnesia-alumina silicate, the lime-magnesia-alumina silicate occupying an intermediate position, and he concluded therefrom (p. 59) that, for the production of pig-iron low in sulphur, pure limestones are to be preferred to those containing magnesia. Much the same opinion has been published elsewhere on high authority, and lately (not to multiply references) by Sir Lowthian

Jan 1, 1895

By George S. Rice

MECHANIZATION in coal mining is a phrase which has attracted world-wide attention, and those persons not engaged on the practical side of coal-mine operations seem to regard mechanization as a panacea for many difficulties of the industry. The term "mechanization" as now employed by experienced mining men is restricted to mean mechanical loading of coal at the face. In a broader sense mechanization in coal mining was begun nearly half a century ago with the introduction of compressed-air undercutting machines and locomotives and, later, of electrically operated locomotives, undercutting and shearing machines, and drills. The use of coal-cutting machines, which has increased until now about three- fourths of the bituminous coal produced is being mechanically cut, first displaced hand-picking except in a few long-wall mines, and later gradually displaced the dangerous and coal-smashing method of blasting-off- the-solid.

Jan 1, 1929

By T. Reed Scollon

Coal reserves of the Rocky Mountain area are vast and are more than adequate to meet significantly increasing demands in the immediate future. Practically all of the increase in coal demand for the next decade or so will be in the electric power utility sector. All ranks of coal are available in the area, and from a technological viewpoint, all are suitable for electric power generation. Location of economically recoverable coal deposits, location of generating plants with respect to power demand areas and sources of cooling water, and availability and price of other fuels are the major factors which, individually or in combination, will determine the ultimate selection of Western coal deposits to be developed for electric power generation. The low sulfur content of most western coals and the non-urban location of many power plants should tend to minimize problems of air pollution. If projections for nuclear power prove correct, increases in demand for Rocky Mountain area coals beyond about 1980 will depend primarily on the extent of commercial development of synthetic fuel processes. Current research activities on the conversion of coal to liquid and gaseous fuels are promising. Most western coals range in rank from lignite through high-volatile bituminous coals and are particularly amenable to conversion. Vast reserves of Rocky Mountain coals have long lain dormant primarily because of their remoteness from major market areas. Recently, however, innovations in coal transportation and electric power transmission methods, combined with unprecedented demands for electric power in the West, have resulted in large-scale development of some of these coals. In the past few years, announcements of coal mine openings and transportation plans in the Southwest have been filled with superlatives: The Navajo mine in northwest New Mexico is expected to be the largest mine in the country in the near future. The largest single coal agreement ever made provides for coal shipment from northeast Arizona to Nevada via the largest and longest coal-slurry pipeline ever used. An 1100-mile haul of coking coal from northern New Mexico to California by unit train began last year. It is the purpose of this report to evaluate the coal resources of the Rocky Mountain area, and to project their potential utilization. In projecting energy demand levels on a national basis, the Bureau of Mines has developed some rather complex techniques to cope with uncertainties. Using these same techniques, an estimate has been made of consumption of Mountain area coal in 1980. No attempt was made to estimate coal consumption beyond 1980, but new market potentials are discussed briefly. The present and potential coal-producing fields of the Rocky Mountain area are in six states comprising the Mountain Region - Arizona, Colorado, Montana, New Mexico, Utah, and Wyoming. Since approximately 19% of the coal produced in these fields is shipped to the Pacific Region (Washington, Oregon, Cali-

Jan 1, 1969

By R. E. Gilchrist, R. R. Harvey, M. R. Dean

A simple and rapid three-component analysis procedure has been developed for use in fluid-flow studies. The method is based on refractive index measurements, combined with refractive dispersion measured between the Ha and H wave lengths. The procedure requires. calibration curves for the three-fluid system. The only restriction on the fluids employed is that only one be an aromatzc or olefinic compound. Individual sample measurements require only a few minutes. Composition results within the limits of accuracy required for fluid-flow analog studies are obtained. INTRODUCTION The simultaneous analysis of three-component mixtures is a problem often encountered in fluid-flow analog systems. In petroleum production research, the problem is usually encountered in experiments on the displacement of fluid from a porous medium. In the case of immiscible displacement, simple volumetric measurements of the produced fluids are usually sufficient, the analog fluids often being the actual reservoir fluids themselves — oil, water and gas. However, modern secondary recovery of petroleum sometimes involves production under miscible conditions, in which the oil is displaced by liquefied petroleum gas which, in turn, is displaced by dry gas. Since this type of displacement is done under conditions of pressure and temperature that are not easily reproduced in the laboratory, studies are often performed with analog fluids at essentially atmospheric pressure. Since the number of samples taken during one of these experiments is usually quite large, the time required for analysis becomes an important factor. In the past, the difficulty of conventional analysis has been avoided by the addition of various tracers to one or more of the components, or by the use of a tracer fluid as one of the components. With these techniques, a relatively large amount of analytical time is still required. Moreover, in the case of added tracers, the tracer material may migrate in part to one of the other fluids, may be adsorbed on the solid surfaces of the model, or may introduce side effects not characteristic of the prototype fluid. The substitution of a tracer fluid for one of the components can severely limit the choice of analog fluids. Optical refractometry provides a rapid and economical method of analysis of two-fluid systems or of monitoring small changes in composition of an essentially one-component system. Refractometric methods are capable of high degrees of accuracy, require only very small samples and can easily be adapted to automatic methods. They are not generally applicable, however, where three or more fluids are present over wide ranges of concentration. The method of three-component analysis described here has three essential characteristics. 1. It is based on refractometric measurements and thus preserves all of these desirable properties. 2. It does not make any stringent demands on the choice of fluids that can be analyzed. 3. It is capable of accuracy sufficient for fluid-flow analog studies. THEORETICAL The difference in the refractive index of a substance at two different wave lengths of light is known as its dispersivity. When the difference is taken between the specific refractions at the two wave lengths, the quantity is referred to as the specific dispersivity. Specific refraction was defined empirically by Gladstone and Dale1 as r = n-1/d....[1] where n is the index of refraction and d is the density. The definition is given more correctly by the expression r =n2-1/n2+1 1/d..........(2) 1References given at end of paper. MICIFTV OF PETROLEUM ENGINEER JOURNAL.

By Wilson 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.

Jan 1, 1934

By George Fowler

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.

Jan 1, 1934

Sec. 1. The membership of the Institute shall comprise six classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6. Rocky Mountain Members. All shall be equally entitled to the privileges of membership, excepting that no member of any class whom residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the claw of Member must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members.

Jan 1, 1941

Sec. 1. The membership of the Institute shall comprise six classes, namely: 1. Members; 2. Honorary Members; 3. Senior Members; 4. Associates; 5. Junior Members; 6. Rocky Mountain Members. All shall be equally entitled to the privileges of membership, excepting that no member of any class whom residence shall be outside of the United States of America, except those residing in Mexico and Canada, shall be entitled to vote. SEC. 2. Members: A person to be eligible for election or transfer into the claw of Member must be at least 27 years of age and must have had at least six years' employment in the practice of engineering, mining, geology, metallurgy, or chemistry, during at least three years of which he must have held positions of responsibility in one or more of these fields. This shall not apply to Rocky Mountain members.

Jan 1, 1939