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By G. S. Baker, S. H. Carpenter

Langenecker has reported significant reduction in strength of high-strength metals during ultrasonic t'ibration. Decreases in static yield stress an order of magnitude greater than the calculated stress amplitude of vibrations were reported by him for a stainless steel and for tungsten. in the present work, attempts were nzadc to verify such large reductions in yield and flats stresses using resonant librations of measured amplitudes. The results show that both the soft metals (copper and aluminum) and the high-strength metals (sleels) hare reductions in yield and .flow stresses no larger than the stress amplitude of libration. BLAHA and Langenecker,' investigating the effect of vibratory stresses on the deformation of zinc and aluminum, found a decrease in the static yield and flow stresses approximately equal to the vibratory stress imposed. Langenecker later extending this work to high-strength metals such as stainless steels and tungsten2 found a much larger effect. In these metals the static yield and flow stresses decreased by an amount more than an order of magnitude greater than the calculated vibratory stresses. It was suggested that this phenomenon could be a serious hazard to high-strength structures in an acoustic environment, such as a large rocket at launch, or could be used advantageously in the working of hard-to-work materials such as the refractory metals. Langenecker and others3 have investigated the effect of high-amplitude vibrations on many metal-forming operations. The results have been quite favorable with usually a large decrease in the energy necessary for the forming operation. The processes, however, involve large frictional forces and it is not clear whether the decreases in forming forces are to be ascribed to decreased friction or to decreased flow stresses. The present paper reports an attempt to determine the effect of accurately known vibratory stresses on the static yield and flow stresses. I) EXPERIMENTAL TECHNIQUE The standard multicomponent resonator technique for measuring internal friction has been adapted to allow simultaneous high-amplitude vibration, internal-friction measurement, and tensile deformation. This has been described in detail elsewhere.4 Longitudinal oscillations of approximately 50 kc frequency are excited in a multicomponent resonator by a quartz transducer. A second transducer measures the amplitude of vibrations. Fig. 1 shows a schematic drawing of the resonator and grip arrangement and the displacement pattern produced. Since the centers of the dummy bars are at displacement nodes, they represent points where attachments will not materially affect the vibrations. The force is applied by a standard Instron tester. The sample may be deformed while simultaneously vibrating at up to 104 strain amplitude. 11) EXPERIMENTAL RESULTS The effect of high-amplitude vibrations on the yield and flow stresses of copper. aluminum, tantalum. a soft iron, and a stainless steel has been measured. In addition samples of tungsten vibrating at stress levels up to 10' dynes per sq cm have been subjected to static stresses near the static yield stress with no indication of macroscopic deformation. Fig. 2 gives typical results for 99.999 pct polycrys-talline copper. A vibratory stress of 7 x 107 dynes per sq cm is applied at points "a" and removed at points "h". The behavior of aluminum is identical. In agree-

Jan 1, 1967

By M. L. Fuller

MOST commercial alloys undergo changes in phase composition after casting. This is a natural result of the fact that the alloys are not in a state of phase equilibrium as cast and phase changes will therefore take place, with more or less rapidity, in an attempt to attain equilibrium. The practical aspect of aging in zinc-alloy die castings concerns the changes in physical properties and in dimensions that may accompany aging phase changes. Harmful alterations have been reduced to a minimum and zinc-alloy die castings are being produced today that are so stable with respect to dimensions and physical properties that they are entirely suitable for most practical purposes1. In the first paper' of this series, and in this paper, aging phase changes of zinc alloy die castings have been investigated and the possible influence of these changes on dimensional changes of the castings has been evalu-ated and compared with the dimensional changes actually experienced. The change of dimensions has been selected for practical comparison in these papers because the effect of phase changes on the dimensions of a casting is directly calculable; from X-ray crystal-analysis data of the phase structure. The die-casting alloys considered contain, in addition to zinc, 4 per cent of aluminum, about 0.03 per cent magnesium, and from 0 to 3 per cent of copper. It was shown in the former paper that the eutectoidal decomposition of the beta aluminum-zinc phase, while intrinsically capable of causing a considerable shrinkage, can have very little effect on the observed shrinkage of die castings because it takes place within a few days of aging, whereas the observed shrinkage continues for five weeks. It was therefore concluded that the other existing phase change,

Jan 1, 1936

By AIME AIME

THE 1941 fall meeting of the Iron and Steel and the Institute- of Metal, Division held at the Ritz-Carlton Hotel, Philadelphia, during the first three days (Oct. 20-22) of the National Metal Congress was well attended as usual, and the seven technical sessions and the joint round table on order-disorder transformations were this year of considerably more than routine interest. Despite unseasonably warm weather, a scarcity of hotels (there were rumors, apparently well-founded, that , some of the metal man attending the Congress had to stay in tourist camp), and a multiplicity of technical and other ions of the co-operating societies that gave the Congress this year the general air of a three-ring circus the A.I.M.E. sessions attracted audiences that ragged from seventy or eighty up to 350

Jan 1, 1941

By M. L. Fuller

MOST commercial alloys undergo changes in phase composition after casting. This is a natural result of the fact that the alloys are not in a state of phase equilibrium as cast and phase changes will therefore take place, with more or less rapidity, in an attempt to attain equilibrium. The practical aspect of aging in zinc-alloy die castings concerns the changes in physical properties and in dimensions that may accompany aging phase changes. Harmful alterations have been reduced to a minimum and zinc-alloy die castings are being produced today that are so stable with respect to dimensions and physical properties that they are entirely suitable for most practical purposes1. In the first paper2 of this series, and in this paper, aging phase changes of zinc alloy die castings have been investigated and the possible influence of these changes on dimensional changes of the castings has been evalu-ated and compared with the dimensional changes actually experienced. The change of dimensions has been selected for practical comparison in these papers because the effect of phase changes on the dimensions of a casting is directly calculable; from X-ray crystal-analysis data of the phase structure. The die-casting alloys considered contain, in addition to zinc, 4 per cent of aluminum, about 0:03 per cent magnesium, and from 0 to 3 per cent of copper. It was shown in the former paper that the eutectoidal decomposition of the beta aluminum-zinc phase, while intrinsically capable of causing a considerable shrinkage, can have very little effect on the observed shrinkage of die castings because it takes place within a few days of aging, whereas the observed shrinkage continues for five weeks. It was therefore concluded that the other existing phase change,

Jan 1, 1935

By J. F. K. Brown

ANTHRACITE?S satisfactory showing in 1942 was accomplished in the face of adverse conditions, such as the loss of man power to the active services and to other industries, and the difficulty and delay in obtaining the necessary materials and equipment required in mining operations. Although the in- creased output was stimulated by the war, and thus does not impress one as contributing to continuing improvement in the industry, nevertheless the year witnessed several efforts ant1 consideration of others that have the appearance of permanent progress.

Jan 1, 1943

By P. Niessen, W. C. Winegard, C. J. Beingessner

DURING the last 10 years, several grain-growth studies have been made using zone-refined metals with controlled amounts of solute to elucidate the interaction of solute with moving boundaries. In all these studies, it was more or less implicitly assumed that the alloys used were, after recrystallization and grain growth, homogeneous within the grains with respect to solute and lattice defects. This note deals with observations made on microstructures originating from solidification of dilute alloys and from grain growth. Briefly, the experimental procedure used in these studies was the following: zone-refined cadmium and master alloys were melted and cast in Pyrex under vacuum to produce bars 14 mm in diam and about 150 mm long. These bars were cut into 8-mm-thick slices which were mechanically and chemically polished. The specimens were then deformed 30 pct in compression and given a 1-week anneal at 260°C in argon. After this anneal, a second deformation produced completely recrystallized samples 4 mm thick. The time-temperature controlled anneals were carried out in a bath of silicone oil. After the grain-growth anneal, the specimens were polished in Gil-man's' solution (33 g CrOs, 6 g NazSO, in 100 ml of water). Several etches were used depending on the alloy investigated, but mostly a mixture of concentrated HC1 and HNOj (98:2 vol) was employed. In all the alloys examined, the ease with which substructures could be revealed depended strongly on the crystallographic orientation of the surfaces of the grains. However, very frequently the microstructures to be discussed here etched up over broad areas comprising several grains. Fig. 1 is a micrograph of a Cd-0.05 at. pct Mg alloy annealed for 100 sec at 270°C. Different substructures are seen in this photograph. A denotes the now existing grain boundaries. The well-defined lines and points marked B are the remains of a solidification substructure. The lines are boundaries between cell colonies, and the points are nodes located on regular two-dimensional cells. This cellular structure has the same appearance as that found by weinberg2 for rapidly quenched Zn-Au alloys. The "ghost boundaries", marked C, are very similar in appearance to a grain boundary array in a polycrystalline sample. Repeated polishing and etching showed that all the substructures observed were three-dimensional. To date, the ghost boundaries have been clearly observed in all samples containing 0.005, 0.01, 0.05, and 1 at. pct Mg, and in samples containing 0.01 at. pct Zn. Attempts to outline these ghost boundaries in cadmium alloys containing 0.01 at. pct Ag and Au were only partially successful. In these alloys, parallel lines, having a resemblance to the ghost boundaries in the Cd-Mg and Cd-Zn alloys, were observed, but it was not possible to obtain complete arrays of ghost boundaries which extended over several grains. It is possible that a different etch than that presently employed would reveal the ghost boundaries in the Cd-Au and Cd-Ag alloys as clearly as in the Cd-Zn and Cd-Mg alloys. A close examination of the ghost structure showed that it consisted of linear etch-pit arrays, Fig. 2. The ghost boundaries were resolvable even in grains which showed over-all faceting due to the etching, as seen in the corner of Fig. 2. The general appearance of the ghost structure suggests that it originated during grain growth. This is supported by the observation that the mesh width in the ghost-boundary array generally increased with increasing final grain size. To test whether the ghost structure was formed during the long homogenizing anneal or during the grain-growth anneal, some as-cast samples were deformed and given a grain-growth anneal. This anneal was terminated by air cooling or

Jan 1, 1967

THE solid nonmetallic inclusions present to some extent in all commercial steels have been variously designated. In early references they were usually called slag inclusions, and this terminology is still retained to some extent. On the premise that all nonmetallic matter produced in a metallurgical process is slag, this can be justified. We have come to think of slag, how- ever, in a more restricted sense, and calling these particles slag inclusions is further objectionable because it fosters the erroneous concept that they are actually incorporated portions of furnace slag. Rarely is this true. The term sonims (coined from solid nonmetallic impurities) was proposed many years ago but never came into common use. In general, the term non- metallic inclusions seems to be satisfactory and adequate. NATURE AND CONSTITUTION OF NONMETALLIC INCLUSIONS From the standpoint of origin, inclusions fall naturally into two classes: (1) those occurring as a result of reactions taking place in the body of molten or solidifying metal and (2) those resulting from mechanical incorporation of refractories or other materials with which molten steel comes in contact. The former are by far the more numerous and have been called indigenous, natural, or native inclusions. The latter are by their very nature sporadic in occurrence and have been called exogenous, accidental, adventitious, or foreign inclusions. They are often referred to as the "slag-stringer" type, though here also the material is not likely to be furnace slag. Substances Found in Inclusions. Nonmetallic inclusions are composed principally of oxides and sulfides but carbides and nitrides sometimes play an important role. In the case of indigenous inclusions the reactions by which these particles are precipitated from molten or solidifying steel may be caused by: (1) oxidation such as may occur during refining or during tapping and teeming, (2) deoxidation by added alloys, (3) change

Jan 1, 1951

By R. L. Wilcox, M. L. Fuller

MOST commercial alloys undergo changes in phase composition after casting. This is a natural result of the fact that the alloys are not in a state of phase equilibrium as cast and phase changes will therefore take place, with more or less rapidity, in an attempt to attain equilibrium. The practical aspect of aging in zinc-alloy die castings concerns the changes in physical properties and in dimensions that may accompany aging phase changes. Harmful alterations have been reduced to a minimum and zinc-alloy die castings are being produced today that are so stable with respect to dimensions and physical properties that they are entirely suitable for most practical purposes1. In the first paper2 of this series, and in this paper, aging phase changes of zinc alloy die castings have been investigated and the possible influence of these changes on dimensional changes of the castings has been evaluated and compared with the dimensional changes actually experienced. The change of dimensions has been selected for practical comparison in these papers because the effect of phase changes on the dimensions of a casting is directly calculable from X-ray crystal-analysis data of the phase structure. The die-casting alloys considered contain, in addition to zinc, 4 per cent of aluminum, about 0.03 per cent magnesium, and from 0 to 3 per cent of copper. It was shown in the former paper that the eutectoidal decomposition of the beta aluminum-zinc phase, while intrinsically capable of causing a considerable shrinkage, can have very little effect on the observed shrinkage of die castings because it takes place within a few days of aging, whereas the observed shrinkage continues for five weeks. It was therefore concluded that the other existing phase change,

Jan 1, 1935

By Edward H. Williams

IN the middle of the eighteenth century John Frazier and wife, Sarah Ingraham, removed from Boston, Mass., to Philadelphia, Pa., where he was held in such esteem that we find him one of the Committee which arranged the ball at Washington's inauguration. Their son John. Nalbro Frazier, was prosperous in his mercantile career and fortunate in his wife, .Anne West; who was an important personage in the early life of Professor Frazier. This cultured lady brought into the family an atmosphere of religious enthusiasm, of thoroughness and: of unity of purpose. Her son, Benjamin West Frazier, inherited her traits and displayed them during a. short and active life. Like his father, he engaged in mercantile pursuits, and was a member of the firm of Zimmerman, Frazier & Co. In their interests he lived for a short- time in Montevideo, and on his return married Isabella Zimmerman, a daughter of the head of the firm. Their happy married life was cut short by the death of Mrs. Frazier shortly after the birth of the subject of this sketch which, occurred October 3, 1841. Mr. Frazier did not long survive her, and left his orphaned sons to, the care of his mother, from whom he had inherited a lovable and deeply religious nature, an : artistic temperament and a capacity for thorough work. Whatever of these traits fell by inheritance to these children were strengthened by the influence of their grandmother, and. the purity of mind, the delicacy of sentiment, the refinement of honor, which characterized. Professor Frazier, are due to Anne West Frazier, and are generally present in the characters of all of gentle blood who have been under the sole and immediate influence of a mature and refined woman. Professor Frazier was educated at the Episcopal Academy in Philadelphia, and passed thence through the University of

Sep 1, 1905

By E. V. Crane

A TREMENDOUS volume of the metal rolled annually into sheets, strips and coil stock finds its way to a host of stamping and manufacturing plants which are the quantity production units of the country. Considerable in volume, too, are the rolled and extruded rods which go into forging and manufacturing plants for conversion into the same general line: those widely sold metallic necessities and luxuries of the household, the office, transportation, farming and building construction. Yet, in spite of its age and its importance, the stamping trade has been doing its "engineering" largely by trial and error. Its distinctive method is shearing out and plastically working metal to finished shape in a few quick strokes with high loads and expensive tools which are warranted only by large quantities to be produced. The principal operations have many features in common with rolling and wire-drawing methods. Combinations of stresses are different, however, and details of operations are infinite in variety. An engineering study of the subject begins with stress analysis, but must go back to metallurgy for its foundation. A grouping of pressed-metal working operations according to whether the metal is (1) sheared, (2) bent, (3) drawn or (4) squeezed has proved useful. All of these groups include instances of both hot and cold operations. For discussions of metal working properties, the division between hot and cold working is taken as the recrystallization range of temperature. This, of course, brings tin, lead and often zinc into the hot-work range at or near room temperature. The outstanding hot-working press field is in forging: particularly of brass; all of which is included in the squeezing group.

Jan 1, 1931

By J. J. Bowman, E. H. Dix

A LACK of experimental data illustrating the effect of composition, particularly in respect to impurities, on the mechanical properties and corrosion resistance of aluminum-alloy die castings induced the authors and their associates to undertake a limited study of these relations. A number of commercial alloys and several experimental variations of a commercial alloy were used for the investigation. Mechanical property, growth, steam, paraffin, salt spray and atmospheric exposure tests were employed. This paper deals with the more accelerated tests and the results they have produced. It is concluded that a high-silicon alloy with all impurities except iron strictly limited to small amounts will develop an excellent resistance to corrosion and retain satisfactory mechanical properties and casting characteristics. As a direct result of this investigation an alloy of this character with superior corrosion resistance is now available commercially. In general, copper increases the strength and decreases the elongation and corrosion resistance. Tin reduces the mechanical properties and the resistance to corrosion. Iron reduces the elongation and, if excessively high, may adversely affect the tensile strength. Even excessively high iron contents do not affect the corrosion resistance, which is fortunate for the die caster as it is this element that is the most difficult to control. Nickel and zinc in limited amounts do not seem to affect the properties or corrosion resistance of at least the high-silicon alloy. Growth tests have confirmed the previous common belief that dimensional changes under either dry or wet conditions at 100° C. are too small to be of practical importance.

Jan 1, 1935

By H. M. Chance

Jan 1, 1886

By Edward Jeffrey

THE use of coke in metallurgy, to any important degree, dates from the middle of the 18th century. Its utilization came most opportunely for European civilization. The forests of Europe, except in the most remote and inaccessible regions, had been largely fed, in the form of charcoal, into the smelting furnaces. For a hundred years-the middle of the 17th to the middle of the 18th century-there was a stationary condition of population corresponding to the exhaustion of European forests. This situation, which was particularly evident in Great Britain, was due to the fact that the forests had been depleted and the practical utilization of coke had not begun. The coking industry is essential for our metallurgical industries, which in turn are basal to healthy economic progress. But coke is of great importance, not only on its own account, but for its byproducts, which enter fundamentally into all the arts of peace and war. The dyestuff industry and the manufacture of explosives are intimately connected with one another, as was shown by the recent war. The subject of coking coal, therefore, is well worthy the serious attention both of practical industry and the scientific investigator. The most valuable coking coals, from the metallurgical standpoint, are derived from the coals of highest ranks. Coals, for example, that have a carbon ratio of from 70 to 80 per cent. yield the most valuable coke for the blast furnace. The difficulty of investigating these coals, however, is great, for they are rather friable and delicate and possess a high carbon content, which makes them difficult to manipulate. They present, on account of their high carbon content, a considerable degree of opacity when examined, in thin sections, under the microscope. The tenderness of structure and blackness of such high-grade coking coals as those of Connellsville and the Pocahontas region make them extremely difficult to investigate.

Jan 1, 1925

By A. C. Fieldner

THE COMMITTEE on Correlation of Research held two meetings in 1931. The first was a luncheon meeting on Feb. 19, at the Engineers Club, New York, attended by eight members and four guests-William H. Bassett, past-president of the Institute; Robert E. Tally, president; H. Foster Bain, secretary; and Alfred D. Flinn, director of the Engineering Foundation. Mr. Bassett gave a short resume of the circumstances leading to the formation of the Committee and expressed his opinion that the objectives as expressed by the Committee in its first annual report were in accordance with the ideas of the Institute officials. Mr. Tally stressed the great importance of research in the mining and metallurgical industries and stated that lie believed the Institute should encourage and promote research, and that this Committee could do a great deal to foster such work in the Institute. Mr. Bain pointed out that this Committee was appointed with a view to correlating and fostering research work. in the field of the Institute's activities. This could be done in various ways, as by encouraging the divisions and committees of the Institute to hold group meetings on research, by forming research subcommittees in the Institute divisions, and by bringing together research interest in. certain projects and the fund or organization that is equipped to carry out the project.

Jan 1, 1932

By Sherwin F. Kelly

FRONTIERS of geological knowledge retreated further this past year before an ever-widening geophysical attack, as governments and endowed institutions continued to take an increasing practical interest in the geophysical line of approach to the study of earth phenomena. A year ago I opened this annual review with a brief account of the efforts to discover what formations lie concealed beneath the deep sediments which form the superficial portions of the Continental Shelf off the eastern United States. That work was but the beginning, and 1938 saw its continuation and expansion. With the assistance of a Guggenheim Fellowship, Maurice Ewing pushed his researches in the development of instruments and techniques for deep-sea seismic refraction studies. Ewing's early refraction profile from the Virginia Capes to the edge of the Continental Shelf has been followed by a similar traverse in Great Britain from the coast of Cornwall to the edge of the Continental Shelf southwest of England. This showed that the thickness of the sedimentary mantle and the rates of slope of the basement surfaces there are comparable to those in the Virginia Cape district.

Jan 1, 1939

By Edward C. Jeffrey

The use of coke in metallurgy, to any important degree, dates from the middle of the 18th century. Its utilization came most opportunely for European civilization. The forests of Europe, except in the most remote and inaccessible regions, had been largely fed, in the form of charcoal, into the smelting furnaces. For a hundred years—the middle of the 17th to the middle of the 18th century—there .was a stationary condition of population corresponding to the exhaustion of European forests. This situation, which was particularly evident in Great Britain, was due to the fact that the forests had been depleted and the practical utilization of coke had not begun. The coking industry is essential for our metallurgical industries, which in turn are basal to healthy economic progress. But coke is of great importance, not only on its own account, but for its byproducts, which enter fundamentally into all the arts of peace and war. The dyestuff industry and the manufacture of explosives are intimately connected with one another, as was shown by the recent war. The subject of coking coal, therefore, is well worthy the serious attention both of practical industry and the scientific investigator. The most valuable coking coals, from the metallurgical standpoint, are derived from the coals of highest ranks. Coals, for example, that have a carbon ratio of from 70 to 80 per cent. yield the most valuable coke for the blast furnace. The difficulty of investigating these coals, however, is great, for they are rather friable and delicate and possess a high carbon content, which makes them difficult to manipulate. They present, on account of their high carbon content, a considerable degree of opacity when examined, in thin sections, under the microscope. The tenderness of structure and blackness of such high-grade coking coals as those of Connellsville and the Pocahontas region make them extremely difficult to investigate. Two of my colleagues, who are taking part in this discussion, will describe the valuable results that have been reached by studying coal by the methods of the mineralogist. Doctor White and Doctor Thiessen have studied the structure of coal as determined from thin sections that

Jan 1, 1925

APPROXIMATELY 90 per cent of the steel that is melted and refined in the United States and poured into ingots is made in basic open-hearth furnaces, as shown in Table 1-1. The annual ingot capacity of the steel industry reported January 1, 1950, by the American Iron and Steel Institute3* was 99,040,160 tons, of which the basic open-hearth process accounted for 85,896,580 tons, 86.7 per cent of the .total. The capacity of the individual furnaces varies over a wide range, a large majority falling within limits of 50 to 200 tons (Fig 1-1). Most of the units constructed [ ] since 1942 are in the larger size groups, between 175 and 225 tons capacity.

Jan 1, 1964

By Cecil H. Desch

THE progress of metallurgical practice and the demands made by the engineering industry on our foundries and mills have made the crystalline structure of metals a subject of far more than academic interest. Metals and alloys are made up of crystals. Even if we accept the view, so ably maintained by some metallurgists, that the crystals are separated from one another by an amorphous layer, it remains true that all but a very minute fraction of any metallic mass is crystalline. The conditions which affect the growth of crystals are therefore of importance in metallurgy. It is not only castings whose properties depend on the arrangement of their crystals, for the more we learn of the behavior of forged, rolled and drawn metals, the more certain it becomes that it is profoundly influenced by the size and arrangement of the crystals in the original ingot, deter- mining a structure which may persist in a modified form through a long series of mechanical operations and annealings. This is mainly due to the concentration of much of the impurities in the last portions of the liquid to freeze, so that the boundaries between single crystals or groups of crystals are marked out by a zone of segregated material, differing in properties from the mass, and offering a barrier to diffusion and equalization of composition throughout the whole. The importance of this fact has been fully recognized by steel manufacturers, who have to deal with ingots which are sometimes very large, and are cast at a high temperature, containing impurities which have a marked effect on the properties even when present in very small quantity. For this reason the Iron and Steel Institute has set up a committee to examine the whole question of the heterogeneity of steel ingots,(l)f and a report has been issued, containing an account of the structure of 16 ingots, ranging in weight from 15 cwt. to 172 tons, each of which was sectioned and examined by chemical analysis and by etching. A valuable body of data concerning segregation has thus been collected. The work of the committee is being prosecuted with great activity, and at the same time researches are in progress to determine the physical

Jan 1, 1927

By C. R. Hayward, H. O. Hofman

I. INTRODUCTION. THE aim of instruction in a metallurgical laboratory is to make real the principles on which metallurgical processes and operations are based, and to foster the spirit of investigation: The materials with which experiments are carried out are ores, metals, and metallic compounds. The method varies with the end sought. A class may work as a whole, each member contributing his share to the solution of a problem, or the students may carry on investigations independently; the former exemplifies class-research; the latter, individual research. It is with a branch of the former, with special reference to ore-treatment that the present paper intends to deal. In smelting an ore by a well-established process, the result is shown by analyzing the products to see whether their compositions correspond to those calculated in making up the charge; by taking account of stock to show the distribution of metal in the different products made and the losses from dust and volatilization, by casting a thermal balance to find the ,distribution and losses of heat; and by making a cost-sheet to ascertain, as far as possible, the necessary outlay of money. In, lixiviation and amalgamation, the mode of operating has to be varied to adapt a process to the individual ore. Here a number of tests become necessary. Each will consist of a series of experiments with one variable, in order to find the conditions under which the variable gives the best result; a. summary of several tests will give the best method of operating.. Working a number of charges with the best method will furnish the data desired for ascertaining the recovery of metal,

Jun 1, 1909

By AIME AIME

THE annual meeting of the A.I.M.E. was fittingly closed with a joint meeting of the Metropolitan sections of the four National societies on Feb. 18, at which this subject was adequately discussed by leading engineers before an audience that completely filled the Engineering Auditorium. The large amount of publicity that has been given the Diesel electric loco- motive, and the often garbled reports of its performance and possibilities that have been circulated, makes it particularly fitting that the facts should be given the profession as determined by those who have aided in developing and operating this latest form of prime- mover in railroad operation. C. A. Stein, general manager of the Central R. R. of New Jersey, opened the meeting with a discussion of the problem of electrification, and the relation of the short haul, switching, and terminal service to heavy electrification. Referring directly to the problem of the Central R. R. of New Jersey, some subtitution for the steam locomotive is necessary within the city limits of New York because of local ordinances against the smoke nuisance. While the improvement in the design of the steam locomotive has been marked-the efiiency today is over fifty times that of the locomotive of 100 years ago-it has now probably reached the point of maximum perfection. If anything, it is open to the criticism of having Coo many appliances to get out of

Jan 1, 1926