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Within the last century, and largely during the latter half of it, the increase of our knowledge of the development of man, both in his search for a livelihood and for power, and in the growth of his reason and conscience, has been greater than all we had known before. The great interest in all kinds of archaeological work and the many excavations made of buried and long forgotten places has put at our disposal historical records not available, and in many cases not known before, and a study of these and other records of human progress from paleontological and geological sources has given us a much broader view of what we call "civilization" than was possible even a short time ago. The old idea that men were created with fully developed minds, speech and reason has yielded to the view that in the upward progress of the human race the development of the mind and reason has been a comparatively recent occurrence, as we think of the half million, and probably more, years that have passed since our earliest records of man were made. The traits that come to us without effort

Jan 1, 1935

By V. K. Zworykin

THROUGHOUT its development the science of electronics, like so many other branches of science and industry, has been indebted to the metallurgist. Metallurgy has provided the electronic engineer with conductors to furnish passage for electrons outside of his evacuated tubes; it. has developed tungsten and tantalum wires for emitting electrons and various refractory metals and alloys suitable for electrodes, which receive them and guide them within the tube; finally it has supplied ferromagnetic materials both for shielding electronic apparatus from magnetic fields and for forming highly concentrated fields for deflecting electron. Today I hope to show you that electronics has not been altogether ungrateful for this assistance. More specifically, I wish to indicate the role that the electron microscope, a relatively recent product of electronic engineering, is playing even now in the study of metals. Every metallographer is aware that his standard metallographic microscope will not reveal structural detail involving separations smaller than a certain fraction -at the very best a tenth-of a micron. This limitation, he knows, is a consequence of the fact that the wave length of the light employed for forming the image has this order of magnitude. It is, thus, a property of all light microscopes. To overcome it, a different imaging medium must be employed. The existence of such a medium became evident when it was demonstrated' that electrons were affected by magnetic and electric fields with axial symmetry just as light is affected by glass lenses; these fields, or "electron lenses," curve the paths of electrons reaching them from an object located on the axis of symmetry in such a manner that, at some distance from the lens, a true image of the object is formed, Furthermore, although a wave length may be ascribed to electron beams just as to light, this wave length is much shorter; for electrons accelerated through a difference of potential of 50 kilovolts, the wave length is only about one hundred-thousandth of that of visible light: Actually, the electron microscopes of today resolve detail one hundred times as fine as light microscopes; if the maximum useful magnification of the latter is taken to be a thousand, that of electron microscopes is one hundred thousand. THE ELECTRON MICROSCOPE Since electrons are readily scattered and absorbed by matter, specimens to be observed in the electron microscope must be prepared to be less than one micron in thickness; furthermore, the interior of the microscope must be carefully evacuated to prevent collisions between the electrons and the molecules of the air. Finally, as already mentioned, the lenses are formed by axially symmetric magnetic or electric fields, and not by any material medium such as glass. Apart from these basic differences, the electron microscope closely

Jan 1, 1943

By Robert Mehl

THE mechanical behavior of metals and alloys is presumably conditioned by two factors; namely, the crystalline symmetry and the interatomic forces. Considerable attention has been given to the first of these factors through the recent advances in X-ray .technique. It is the purpose of the present paper to call attention to the importance of the second of these factors, to point out promising methods of investigation, and to present some pertinent data. Plastic deformation takes place by-slip along atomic planes.1 This slip may be inhibited in a number of ways: by the interatomic forces of cohesion which bind the atoms rigidly in a lattice structure, which in pure metals is usually of high symmetry; by lattice distortion caused by solid ,solution formation or by mechanical strain; by the intercrystalline boundaries where slip is restrained by the non-registration of the atom planes in adjacent crystallites;2 and by the presence of small hard particles which serve to "key" the slip along the atom planes.3 In pure metals, and perhaps also in solid solutions, the atom planes, of easiest slip are those exhibiting the greatest density of atomic population and the greatest interplanar distance4 and apparently can now be predicted from the analysis of the lattices. Concerning the interatornic forces, which resist this slip by holding the atoms firmly together, little is known. Most textbooks on physical metallurgy, following the work of Bot-tone,5 correlate the hardness of the pure metals with the atomic volume;.

Jan 1, 1928

By J. C. Mertz, C. H. Mathewson

Accurate knowledge of the solid solubilities of the elements that dissolve in the important base metals is needed for guidance in the preparation and heat-treatment of the alloys derived from these components. While there is still difference of opinion concerning the merits of the X-ray and microscopic methods of determining such solubilities, it is certainly true that the recent extensive use of X-ray diffraction to review the existing constitutional data has revealed many glaring inaccuracies and has brought about a much improved knowledge of phase-boundary locations, which will inevitably come to include all of the important alloy systems. When the work is done with all necessary precautions it appears that in the majority of cases where the solubilities extend beyond a few tenths of a per cent the X-ray back-reflection technique is capable of furnishing the best of information in this field. For the most prolonged and thorough studies it is obviously advisable to combine the results of several methods, in particular, to obtain an agreement between X-ray and microscopic data. This paper reviews the work previously done on the solubilities of phosphorus, arsenic, antimony and bismuth in copper and, in consideration of the uncertainties thus made apparent, presents new X-ray data obtained with the first three members of this group. Copper-phosphorus System Heyn and Baurl found that in slowly cooled alloys phosphorus forms a solid solution with copper up to about 0.175 per cent. Huntington

Jan 1, 1937

By W. E. D. Jr. Stokes

THE application of aviation to mining and petroleum operations, on the basis of economy and attainment, has become a demonstrated fact. According to Dominion Government records, 30. Canadian companies engaged in air transportation with northland mining camps, carried 13,000 tons of freight in 1935, and in 1936 carried 16,000 tons. In addition, many mining companies used planes to transport prospectors with canoes, outboard motors, gasoline drums and supplies to remote locations, and one company maintained a plane to take radium-bearing ore from its mine on Great Bear Lake nearly 1000 miles south to the rail-way at Waterways, Alberta. Heavy pieces of mining machinery weighing 2 tons are being carried by Ford trimotor planes over the Andes, at an altitude of not less than 15,000 feet. At Bulolo, New Guinea, 17,500 tons of disassembled gold-dredging equipment has been flown over inaccessible terrain, while supplies and building materials for a, community of 1000 whites have been transported by airplane. A 31..4-ton shaft was carried on one notable trip, while at another time an automobile, 2 tons of rice and a large safe went over the mountains in one plane. Fig. 1 shows an electric generator that was carried by plane to Bulolo. Many large American oil companies operated fleets of planes during 19:36, ranging from fast, luxurious air liners for executives to elaborate geological prospecting units, ambulance planes, freight carriers and pipe-line repair crews. According to the U. S. Geological Survey, commercial firms photo-graphed 16,291 square miles during 1935, while the Government compiled from aerial photographs by the Geological Survey in the United States 85,544 square miles. It was found that information could be determined in a fraction of the time required by surface methods.

Jan 1, 1937

By W. R. Foster, J. M. McMillen, A. S. Odeh

The complete equations of average linear momentum balance for a single-phase fluid in an incompreisible, homogeneous, porous medium are derived. The derivation begins with Euler's equation of motion for a continuum and uses an integral transform recently developed by Slattery. 7 For steady flow of a compressible, Newtonian fluid, the usual equations of motion result. For transient flow, the space-time description of the pressure is determined in the lowest approximation by the telegrapher's equation. From the analysis a new phenomenological coefficient results which connects the viscous traction to the deriv ative of the linear momentum density. The magnitude of this coefficient determines the velocity of sound through the pore structure in this approximation to the pressure field. INTRODUCTION The modification of Darcy's law of momentum balance for steady, single-phase flow through porous media has been discussed for many years. The first modification was suggested by Forcheimerl who added terms of higher order in the velocity. These can be expected to appear because the underlying microscopic equations of momentum balance are themselves nonlinear in the point velocity field. The Reynolds tensor pvv, which represents the convective flux of momentum density, appears in the momentum balance equation. Only in rectilinear flow (parallel stream lines) does the divergence of this tensor vanish. Since the steady flow stream lines in most porous media are not parallel, nonlinear dependence of the pressure gradient on the velocity should naturally appear. This nonlinearity has nothing to do with turbulence in the ordinary sense of random fluctuations in the pressure and velocity fields. It arises simply because the stream lines converge and diverge, even for steady flows. Klinkenberg2 demonstrated that the permeability coefficient in Darcy's law depends on the absolute pressure or, alternatively, on the density field. However, because he neglected inertial terms of the Forcheimer type, his correction coefficient could not be represented by a constant but tended toward a constant as the velocity decreased. Forcheimer's and Klinkenberg's modifications can be combined in a rigorous way to account for both inertia and slip during steady flow. This will be shown in a future paper. The transient change of pressure in porous media has been described by the diffusion equation.3 This form results from eliminating the velocity and density fields from a combination of the equations of motion in the form of Darcy's law, the continuity equation and an equation of state. Fatt4 suggested that the cause of deviations from the prediction of the diffusion equation for pressure transients lies not in the choice of Darcy's law as the equation of motion but on the existence of dead-end pores which might invalidate the averaged equation of continuity. On the other hand, Oroveanu and Pascal5 noted chat the time derivative of the momentum density must be included in the equations of motion since this measures the local rate of change of momentum density. Their differential equation for pressure is the telegrapher's equation (neglecting gravity). However, their form of this equation predicts that the speed of pressure propagation through the pore structure is the same as that through the bulk fluid. M. K. Hubbert6 attempted a derivation of Darcy's law by volume averaging the Navier-Stokes equations. Since these equations represent momentum balance at a point within an open set of points containing the fluid itself, Hubbert's volume averaging cannot lead to tenns involving transfer of momentum between the fluid and the walls of the pores. Once these viscous tractions are lost by choosing a control volume containing only fluid, they cannot

NEW MEMBERS The following list comprises the names of those persons who became .members during the period of Jan. 10, 1918, to Feb. 10, 1918. ANTISELL, TONER, Min. Engr.; Supt., Great Falls Mine of Maryland, Chevy Chase, R: F. D. No. 4, Washington, D. C. BAKER, RAYMOND FRANK, Geol:, The Texas Co., Producing Dept., Box 362, Tulsa, Okla. BERTON, ADRIEN, Chief Engr., Corocoro United Copper Mines, Ltd., Corocoro, Bolivia. Buck, WILMER EARLE, Met., Curtis & Co. Mfg. Co., Hamberger & Kienlein Aves., St. Louis, Mo. BUELL, WILLIAM H., Asst. Director, Experimental Station, E. I. duPont de Nemours & Co., Wilmington, Del. CARDENAS, FEDERICO F., Mgr., Cia. Minera Nazareno y Alicante, S. A., Allende, No. 112, Saltillo, Coah., Mexico. CHEVALIER, JEROME A., Pet. Geol., The Carter Oil Co.; Exchange National Bank Bldg., Tulsa, Okla. CLEAVES, DANIEL LUNT Supt., St. Joseph Lead Co., Herculaneum, Mo. CLOTHIER, GEORGE A., Resident Min. Engr., Province of British Columbia,

Jan 3, 1918

By R. W. Raymond

There is apparently no end to the doubts, inconsistencies and absurdities in which the courts of our mining States and Territories are involved in their attempts to apply to conditions of ever-increasing complexity the provisions of our anomalous mining law. In previous papers, I have called this statute " the law of the apex," because it based upon that vague, novel and mysterious condition the most important grant of title. But the apex is scarcely a more essential feature than the end-lines and the side-lines; for the rights which it may confer may be limited in various ways by these; so that we have, in many a case, the most ridiculous result that the United States, in return for the money of a citizen, conveys to him with much solemnity, under its broad seal, nobody knows what, bounded nobody can tell how. A decision recently made at Butte by Judge De Wolfe, of the United States District Court of Montana, in the case of King et al. vs. The Amy and Silversmith Mining Company, furnishes a fresh illustration of this criticism. The diagram on the following page, constructed without precise regard to courses and distances, simply to assist in the statement of the essential features of the case, will, 1 hope, make clear the principles . involved : The plaintiff occupies a location (the Nonconsolidated) adjoining on the north the defendant's location, a b c d (the Amy), and the disputed mining-ground lies, let us say, in depth under the point W, that is, on the dip of the vein, VD, but not under the surfacelocation, a b c d. The defendant has the prior title, and claims this ground under its extra-lateral right. It is admitted that the apex does not cross the end-line, a d, and does cross the side-line, a b. Whether it crosses, at the other end of the location, the end-line, b c

Jan 1, 1889

By S. F. Emmons

There is, in the southern part of the State of Illinois, a series of deposits of fluorspar and galena in which the former mineral occurs on a scale of magnitude unequalled, so far as I know, in any other part of the world. In June, 1891, 1 had an opportunity of visiting the region of their principal development, near Rosiclare, Hardin county, Ill., and examined such of the mines in the vicinity as were accessible at that time. A very large proportion of the mining shafts that had been sunk in this region were unfortunately abandoned for the time being, and full of water. Moreover, detailed maps of the region are unattainable, no surveys having been made there, apparently, since the original land-surveys' of the early part of the century. In spite of these disadvantages I was enabled, in the few days at my disposal, to ascertain with sufficient accuracy certain facts not hitherto published with regard to these deposits, which seem worthy the attention of the members of the Institute. Before proceeding to a description of the deposits in question, I will give a brief abstract of the little historical and geological information hearing directly or indirectly upon them, which I have been able to find in existing publications. Historical. That the mineral was known to the Indians, is proved by the discovery, in some of the pre-historic mounds of the region,* of fluorspar, shaped into ornaments. The earliest scientific mention of its occurrence is found in the first volume of the American Journal of Science (1818+), which describes specimens obtained in the vicinity of Shawneetown by Mr. Joseph Baldwin. Similar notices appear in the same journal in 1820 and 1821, but without mention of the exact locality. They remark on the fetid odor which characterizes the mineral and its association with galena. Schoolcraft, as early as 1819, note: the occurrence of fluate of

Jan 1, 1893

By L. D. Jaffe, D. C. Buffum

EARLIER the authors and coworkers had pre sented data on isothermal temper embrittlement of an SAE 3140 steel?' In that work, however, attention was concentrated on embrittlement at 575°C and below. Preliminary measurements showed that embrittlement at 675 °C was much mote rapid than would be expected from the data at the lower temperatures: and indicated the need for further work above 575°C. The possibility of an upper nose in the time-temperature embrittlement diagram above 575°C was pointed out. Procedure The same heat of SAE 3140 steel was used as in the previous work, and experimental methods were the same. All blanks were austenitized 1 hr at 900°C and water, quenched. Groups were then tempered 1 hr at 675"C, water quenched, and given embrittling treatments for times of 5 min to 240 hr at 675" to 600 °C, as shown in Table I. Other groups, after the temper and quench, were embrittled 48 to 1440 hr at 550°C. Another series was tempered 240 hr at 675"C, quenched, and held for various times at 650" to 375°C (Table 11). For comparison, a series was tempered for these same times at 700°, 675", and 650°C (Table 111). The Ae, temperature for this heat of steel had been determined as approximately 690°C;1*a the treatments at 700°C were introduced to determine the effects of tempering in a range where a little austenite would fonn. A large number of other treatments, involving holding at two temperatures in succession after the temper, and occasionally slow cooling or heating, were also studied. These treatments are listed in the tables. Austenitizing was done in air; all subsequent treatments were in salt. Blanks were always water quenched after the last treatment. The heat-treated blanks were machined to standard V-notch Charpy specimens. A transition curve for each group was obtained by breaking the specimens at various temperatures on a 217 ft-lb impact machine having a striking velocity of 16.8 fps, and plotting the observed percentage of fibrous fracture vs the test temperature. From this plot, the transition temperature was taken as the lowest temperature at which the fracture appeared 100 pct fibrous; its accuracy is estimated as +5"C. Generally, hardness was measured on every bar. Since a decrease in hardness itself seems to decrease the transition temperature somewhat, a correctiona of —0.28"C per Bhn was applied to permit comparison of the transition temperatures on a uniform basis of 24 Rc. The transition temperature and hardness results are given in Tables I through VI. Where overlap of earlier work1.' occurred, data were combined.

Jan 1, 1958

By CHARLES R. KETES

I. INTRODUCTORY. INDUSTRIALLY, the most important service that geological science can now render to mining in the Upper Mississippi leadand zinc-fields is to devise some practical scheme whereby the productive ore-belts may be located with greater certainty than they have been in the past. Up to the present time there has been little service of this kind, and in spite of all that has been worked out concerning the geologic features of the region, and notwithstanding all that has been written about these ore-deposits, this particular phase of the subject has been, for some reason or other, the very one that has received the least consideration. The neglect by geologists in this respect has been all but complete. The following notes are suggestive of some practical solutions to the problems presented. As here suggested, the geologic relationships of the ore-bodies were surmised some years ago, though somewhat vaguely perhaps. No opportunity for securing critical data appeared until recent investigations of a private character were undertaken, which bad in view the extensive prospecting of undeveloped areas. Fresh from rather wide experiences of a decade in the principal mining-regions of four continents, and after a lenstrum's residence among the chief mining-camps of the West and of Mexico, under conditions which measured geologic hypotheses in meters and rigidly tested their values in, terms of dollars, the recent return to the Joplin field and a new survey of its ore-conditions were fraught with somewhat unexpected results. Aspects of the ore-deposition were presented of which previously there was no hint. Ten years' absence from the district had tended greatly to clarify former hazy impressions. It enabled many features, then only dimly outlined, to be considered more nearly in their true perspective and in their real relationships to their surroundings. It permitted a great mass of details collected a dozen years before in connection with the work of the Missouri Geological Survey to be viewed under new light and to

Feb 1, 1909

By Thomas V. Falkie

4.3-1. Introduction. DEFINITION OF PRODUCTION SYSTEMS ENGINEERING. Surface mines, like most other mining and manufacturing operations, are usually organized along functional departmental lines. Frequently a mine manager will have his responsibilities divided among production, maintenance, administrative, and engineering functions. Often these are separate departments, but various combinations and variations of these functions can be found in mining companies throughout the world. The production function is responsible for physically removing the ore from the ground, processing it, and shipping the product to its market. The production manager supervises and is responsible for all man-machine systems necessary to extract and process the ore. The maintenance function, which is sometimes included within the framework of production, has the task of insuring the maximum availability and longevity of equipment needed to produce the ore. The administrative function is responsible for accounting, personnel, industrial relations, purchasing, public relations, property, and other related staff functions. For purposes of this chapter, engineering can be described as the function which plans, designs, and supervises construction of physical plant and equipment. In this context engineering includes mechanical, civil, chemical, electrical, and mining engineering. However, another phase of engineering is to prepare plans to insure that the various man-machine components function in an optimum way towards the single most important goal of any enterprise-the maximization of return on the investors' money. Along with the planning, another duty of engineering is to audit all phases of the operation for the purpose of recommending improvements toward this same general goal. These latter two ideas form the basis for a discussion of production engineering and systems engineering. Production engineering is a catchall, problem-oriented function whose duties can include: 1) solution of day-to-day production problems, 2) short-

Jan 1, 1968

By J. D. Pennock

About a year and a half ago, Mr. Morris, an engineer of the Solvay Process Company, was sent to Belgium and France to study the manufacture of coke in the Semet-Solvay ovens, which were in operation at Havre. With complete plans of construction and a good understanding of the methods of running the ovens, he returned to Syracuse. Work on twelve Semet-Solvay ovens was immediately begun. These ovens, with plant for crushing and washing coal, and the necessary condensers, scrubbers, and concentrator for the recovery of the byproducts are nearly finished, and will soon be in operation. As the work approached completion it became necessary to determine what coal should be used. Accordingly, a chemical investigation of the various bituminous coals was made. I. Investigation of Coals. The samples of coal taken for analysis were: I. A sample of Reynoldsville coal that had been exposed to the weather for a year; 11. Reynoldsville coal taken from a car direct from the mine; 111. Morris Run lump coal; IV. Morris Run fine coal; V. Coal from the Fairmount Coal and Coke Company; VI. A special enginecoal from Pardee colliery, Phillipsburg, Pa.; VII. South Fork, Pa., coal; VIII. Coal from Laceyville, Ill.; IX. Pittsburgh bituminous coal from Ocean mines (gas-coal); X. Steubenville, Ohio, coal; XI. Evansville, Indiana, coal; XII. Coal from the Ohio Coal Company. Proximate Analysis. I. 11, 111. IV. V. VI. Water at 90° C.,* ..................................... Volatile,. .. 31.14 33.00 17.73 18.12 37.20 23.86 Fixed Carbon,. . 64.49 58.07 71.92 71.89 56.68 73.00 Ash,. .. 4.37 8.93 10.35 9.99 6.12 3.14 Coke,. .. 68.86 67.00 82.27 81.88 61.88 76.80

Jan 1, 1893

By William Fink

ALTHOUGH age-hardening in an aluminum-base alloy containing magnesium was observed by Alfred Wilm1 as early as 1911, it was not until 1919 that a theory of the mechanism of age-hardening was proposed. Merica, Waltenberg and Scott,2 studying the age-hardening character-istics of Duralumin at the National Bureau of Standards, came to the conclusion that age-hardening of this alloy is caused by the precipitation of CuAl2, which is less soluble at the aging temperature than at the solu¬tion heat-treating temperature. It was postulated that the initially precipitated particles were of fine colloidal dimensions but that they gradually grew in size. Maximum hardness was assumed to be attained when the particles reached a critical size. This theory was at first received skeptically, since it was a widely accepted view at that time that the solid solution state should represent the hardest state of an alloy. Shortly thereafter, Jeffries and Archer proposed their well-known "slip interference theory."3 They suggested that age-hardening was accomplished by the precipitated particles acting as keys interfering with slip along crystallographic glide planes. They showed that this mechanical theory led directly to the assumption that maximum harden-ing would be produced by particles of a critical size, which they suggested would have a diameter approximately 10 times that of the aluminum atom. This contribution amplified and explained so rationally the age-hardening theory of Merica, Waltenberg and Scott that wide accept-ance resulted.

Jan 1, 1939

By Alexandre Pourcel

The phenomena of liquation in steel or iron ingots of all sizes, but naturally to greatest extent in the heaviest ingots, have been noticed ever since the commencement on a large scale of the Besse mer and open-hearth manufactures; but they have been studied with care during the last few years only. The English and the Ameri cans were the first to publish the results of investigation upon phe nomena of this clam, to which they have given the name of segregation. Historical. Passing by that which has been written concerning the segregation observed in gray pig-iron, of which instances were given by Karsten, we shall confine ourselves here to that which is known of this subject with exclusive reference to ingot steel and iron. Mr. H. M. Howe, of Boston, in his Metallurgy of Steel, the most complete and well-arranged treatise upon steel, gives a resume of observations, with the results of numerous analyses, bearing upon the phenomena of segregation. According to Tchernoff (with whom we discussed this question at length in 1878, in connection with the cast-steel plates of large dimensions designed for the Italian fleet, which we showed him at Terre-Noire), Kalakoutsky called attention in 1866 to the lack of homogeneity in Bessemer ingots, especially when cast in sand. Our own attention had been called to the phenomena of liquation in 1868 by a somewhat surprising fact which appeared in almost every one of a number of steel-rail ingots coming from the works of Messrs. Pierre and Emile Martin at Sireuil, to be rolled at TerreNoire. In the heating or in the first groove of the rolls, a slice of from 6 to 10 centimeters (2.4 to 3.9 inches) separated itself from the head of each ingot. As a general consequence, the section of

Jan 1, 1894

By D. A. Dahlstrom

Application of the cyclone to separation of undesirable -200-mesh clay, silt, and high-ash fractions from coal slurries was found to possess many economic and process advantages. Up to 93.3 pct removal was attained at rates of 113 to 155 gpm per sq ft of cross-sectional area.

Jan 2, 1951

By L. C. Morganroth

Magnesites are of two general classes - massive and crystalline.

Jan 1, 1915

By W. D. Forgeng, B. F. Decker

IT has been known for almost a century' that silicon and nitrogen combine when heated to a high temperature. Three nitrides have been reported, SiN, Si3N,, and Si,N, containing 33.3, 40.0 and 42.9 pct nitrogen by weight, respectively. The existence of SisN, is well established but that of Si,N, and SiN is doubtful. The first systematic study of the reaction between silicon and nitrogen was made in 1910 by Weiss and Engelhart" who determined the rate at which silicon absorbed nitrogen at temperatures from 1250°C to

Jan 1, 1959

A $5000 contract to explore for asbestos in Marinette County. Wis., has been entered into between the Government and the Star Mining Co. of Madison, Wis. The Government will contribute 90 pct or $4500 to the cost of the project. The United States presently produces about 8 pct of its asbestos requirements. "Sulphur stockpiles are at a minimum for national security arid must not be further reduced," was the warning given by L. M. Williams, Jr., president of Freeport Sulphur Co. He stated that although the long-range outlook is favorable , current sulphur production cannot meet the demand and as a result the United States faces a crisis in the coming months.

Jan 12, 1951

By Henry M. Howe

The object of the present paper is to suggest injecting into the hearths of iron blast furnaces, whose temperature has become unduly lowered, some form of fuel whose calorific intensity, under the peculiar conditions existing there, is considerably higher than than of liquid petroleum, the rose of this substance for melting out chills having grievonsly disappointed the high hopes which were at first entertained of it. A chill being a fall of the temperature below that needed for the complete liquefaction of the slag, which requires, according to Plattner, about 1800' C., one would suppose that the chief thing to be accomplished in curing it would be to raise the temperature in the crucible of the furnace. The most obvious ways of doing this seem to be to raise the temperature of the blast, and to increase the amount of fuel in the crucible itself. Simply increasing the rate at which the blast enters the furnace, if carried beyond a certain point, should lower the temperature in the crucible. The existence of a chill shows that the fuel is arriving too slowly at the tuyeres. If air be introduced so rapidly as to he in excess of that required for the combustion of the fuel, all that excess will simply lower the temperature around the tuyeres, carrying the region of intense heat upwards, and weakening its intensity by increasing its size. Up to a certain point, increasing the rate of introducing the blast will increase practically pari passu the rate at which the fuel reaches the tuyeres. But when mechanical obstructions, which so often accompany chills, retard the descent of the fuel, there must be a point beyond which this does not hold good, and beyond which farther

Jan 1, 1883