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By C. G. Dunn, F. W. Daniels, M. J. Bolton

J. P. Nielsen—The data that Dr. Dunn and his associates have been obtaining are welcome checks on the theoretical aspects of grain boundary energies. With reference to the comments on the validity of the inter-facial tension concept, I should like to say that I have been having considerable difficulty myself in untangling the confusion between "interfacial tension" and "interfacial energy." The confusion however resolved itself for me when I learned that "interfacial tension" for solids, or at least crystals, is used with two distinct meanings. One meaning12. ' "hat is implied for "interfacial tension" is the work necessary to produce or increase the surface of the solid in question by a unit area, temperature and pressure held constant. This comes from the somewhat surprising but simple fact that surface tension and surface energy in the case of liquids are identical quantities. This synonymity has carried over to crystals, where it should be kept in mind that the tension connotation has meaning only by analogy with liquids and that no real stresses are being referred to. The only reason that there is apparently a set of stresses acting at a grain boundary junction is the optical illusion that liquid interfaces are being observed for the grain boundaries. The other meaning3,14,15 for the term has to do with actual states of stress in the surface of a material as would be measured by a system of forces applied to the surface to equate the surface stress state with that in the body of the crystal. J. B. Hess—Since the authors have proposed that the surface tension concept should be discarded in order to deal with the general case of interface energies in solids, their attention should be called to a recent paper by Gurney." The latter has shown, from a thermodynamic argument, that surface tension is a valid concept in solids. In fact, Gurney has rejected the idea that surface tensions are merely mathematical fiction and, instead, has given an interpretation of their physical reality. Finally, he has concluded that, as long as appreciable atomic migration takes place, specific surface energies and surface tensions must be equivalent in solids as well as in liquids. Accordingly, the authors' eqs 2 and 3 can be written with equal accuracy in terms of interface tensions, simply by replacing each E,! with its numerically and dimension-ally equivalent Interfacial tension ?,,. If the interfacial tensions (or specific energies) are independent of interfacial orientation, as is true in liquids, then the general equations that define the geometry at equilibrium of the common junction of three interfaces reduce to eq 1. However, neglect of the effect of boundary orientation is never completely justified theoretically' in dealing with crystalline solids; hence, use of eq 1 in such cases must always be considered as an approximation, though clearly a reasonable one for many purposes.1,2 At the same time, one should not be surprised that the assumption that interface tensions in solids are free from orientation

Jan 1, 1951

By Charles R. Holmes

MORE than 70 igneous pipes and dikes are known to occur in Cambrian sediments throughout an approximately circular area of about 75 sq miles in southwestern Ste. Genevieve County and southeastern St. Francois County, Mo., across the southern portion of the Farmington anticline, which is outlined in fig. 1. From evidence obtained from fossil fragments taken from some of the intrusive, and from the similarity in composition of the more basic intrusives to those of known age in surrounding states, these pipes and dikes are believed to be at least post-Devonian and probably Cretaceous in age. As first postulated by Rust, these intrusives are believed to represent explosion tubes, or diatremes, punched through great thicknesses of solid rock by gaseous pressure. The particular intrusive studied is located about 1 mile north of the small town of Avon at an elevation of 880 ft in the EM SES NE% of sec. 2, T. 35N, R. 7E. Outcrop is through the Bonneterre dolomite in two separated exposures. The larger outcrop extends east and west for about 50 ft along a tributary in a small ravine (fig. 2). The smaller exposure occurs as a few scattered patches over an area 20 ft square about 100 ft to the north. The area between the exposures is covered, but scattered patches of the Bonneterre dolomite outcrop throughout the area surrounding the diatreme. Where exposed, contact relations show the surrounding dolomite to be shattered and metamor- phosed to a fine-grained rock for a distance of 15 to 20 ft from the intrusive. The igneous rock occurs as a dark greenish-gray porphyry near the center of the diatreme and as a fine-grained, greenish-gray material containing lapilli and metamorphosed fragments of dolomite near the contact with the country rock. The most abundant original mineral of the porphyritic rock is olivine now largely serpentinized as the result of extensive hydrothermal alteration at time of emplacement. The most common constituent of the fine-grained rock, which occurs near the border of the intrusive, is calcite. Mica is a common constituent of both types of rock, occurring as tufts or

Jan 1, 1950

By AIME AIME

THAT neither the Reconstruction Finance Corp. nor its subsidiary, the Metals Reserve Corp., are in competition with private enterprise was stressed by Charles B. Henderson in an informal talk before the N. Y. Section, A.I.M.E., on Sept. 23. Among other things, the speaker stated that the R.F.C., since its establishment, had authorized loans of $12,000,000, of which over $8,775,000 has actually been distributed. Of this amount, over $6,600,000 has been repaid. None of this money was appropriated by Congress, the sole assistance from that body being the initial authorization of $500,000,000 capital stock.

Jan 1, 1941

Jan 1, 1910

By H. C. Ray

ABOUT the beginning of 1930, coal preparation had reached the stage where the cleaning of coal by liquid or air had become the order of the day. Since that time many new preparation plants have been installed in spite of the years of depression in the coal industry, and this is indicative of a trend wherein the coal producer found it expedient to manufacture a cleaner product in order to compete with other fuels. It was also about 1930 that, because of the difficulties encountered with fine coal in cleaning plants, dust collectors came into use. Both cleaning plants and dust collectors, therefore, were much discussed at the engineering meetings of the early 1930's. During these meetings the many advantages to be gained through the use of dust- collecting systems were pointed out by Hebley,1 Appleyard2 and others. The great possibilities of new markets for this product were emphasized and discussed at the same time; however, the disposal of the collected dust remained a problem. Since the purpose of dust collecting is to improve the preparation and, consequently, the salability of the coal, it seems illogical to return the collected dust to any of the coal being prepared for market use, as is done in preparation plants that include dust-collecting systems. The logical thing is to dispose of the dust in some useful and practical manner outside of the tipple. As a practical matter, this can be done in one or both of two ways; either by consuming the dust at the mine's own power plant or by marketing the dust direct to the consumer. The latter method not only offers the greatest opportunities, but is the most important, because of inequalities that may exist between the quantity of dust collected and the consuming capacity of the mine's power plant. In considering the more important marketing possibilities, we are confronted immediately with the problems connected with the handling and transportation of so fine a material. It is this problem, rather than the problem of finding new markets, that has been responsible for the lack of progress in the matter of dust disposal. It is the purpose of this paper to point out again some of the potential market out- lets, and also to describe an existing system of handling and transporting coal dust. To the best of the writer's knowledge, this is the first and only operation in this country that has handled fine-mesh coal in bulk so-ton lots direct to the consumer. POTENTIAL MARKETS FOR FINE- MESH COAL DUST In general, the potential market outlets would include any operation of which the pulverization of coal is a necessary part. To be more specific, a few of the better known operations of this type must include: colloidal-fuel plants, briquetting plants, “sea coal” distributing plants, water-purification plants and obviously, pow-

Jan 1, 1944

By W. Robert Power

Dimension stone is considered by many the premium material for beauty and durability in institutional and monumental construction. Nonetheless in the United States it commands an ever decreasing share of the total market. At the beginning of the century dimension stone accounted for more than half the stone produced in the United States, but by 1974 it accounted for little more than 0.2% and the number of producing quarries and finishing plants had greatly reduced. This decrease in use is accounted for in part by competition from cheaper materials, but another factor seems to be the demand by many designers for uniformity and exact repetition of modular units in construction. Even where stone is used in large buildings modem architects want blandness of pattern and uniformity of color in the stone. Because most natural stone contains variations in color and pattern great strain is put on the quarriers to overcome this and produce a uniform product. This results in increased costs, increased waste at the quarries, and consequently increased price in the market. In spite of this, stone is still looked on as the most prestigious of building materials and its aesthetic appeal is born out by the many simulated stone patterns found in synthetic materials. End Use and Specifications The principal uses of dimension stone are in building construction and monuments. Other uses include flagging, curbing, paving, mill-stock slate, roofing slate, laboratory furniture, and refractory brick. Because many of these uses overlap, an orderly classification of dimension stone uses is most difficult. Various classifications have been used by Cumer (1960), Barton (1968), the U.S. Bureau of Mines yearbooks, and the Building Stone Institute (Anon., 1972).

Jan 1, 1975

By Per Larsson

The Chapin Mine, on the Menominee range, Lake Superior, was first opened in 1880 and has since then produced 1 1/2 million tons of soft blue hematite, containing about 63 per cent. of iron and 0.07 per cent. of phosphorus. Up to the present time, the ore has been mined from three separate lenticular deposits, which conform with the Huronian strata of the district, striking N. 75' W., dipping from 70' to 80' N., and pitching about 30' W. The largest of these ore-bodies has a horizontal length of 2500 feet, and a maximum width of 130 feet in the middle, from which it gradually narrows to the pointed ends. Its dimensions have not changed materially as greater depth has been attained. Figs. 1 and 2 show the geology and the mine-workings on the main deposit.. As this main deposit pitches away from the eastern part of the property, it is replaced by another lens, containing ore of the same quality. When first opened on the 1st level, this lens was 150 feet long and up to 50 feet wide, while now on the 6th level it shows a length of 550 feet, and a maximum width of 100 feet. It is separated from the extreme east end of the main deposit by about 30 feet of clay-slates It pinches out gradually between the slates to the west, and stops abruptly against the jasper to the east. Farther east in this belt of jasper occurs the third ore-lens which has a pretty regular length of 100 feet and averages, from the 1st to the 5th level, 20 feet in width. A cross-section of the ore-formation shows, on the north or hanging side of the ore, about 200 feet of clay-slates, and farther north a heavy belt of magnesian limestone. The slates and the dolomite are generally separated near the surface by a conglomerate of broken dolomite and soft slates. The foot-wall rock is also a clay-slate, containing a higher percentage of iron and less magnesia than the hanging-slate. Farther south occur alternate beds of slates and lean ore or jasper.

Jan 1, 1888

By Leonard H. Goldman, Harold E. Marr

The PGT uranium assay probe is a borehole tool developed by Princeton Gamma-Tech over the last several years. It has the ability to do an in-situ assay of uranium in the presence of any amount of disequilibrium. It has some advantages over coring including cost, speed of analysis, and accuracy. In this paper we would like to give a brief description of the measurement and then show some sample logs from South Texas. Uranium exploration and development is carried out primarily by gamma logging since uranium daughters are prolific emitters of gamma rays. The conventional gross gamma tool for uranium logging is limited in value because of the inability of this tool to distinguish uranium from its daughters and other naturally occurring radioisotopes, such as potassium and thorium. This problem becomes severe in cases of disequilibrium. Disequilibrium, in a geological context, is defined as the condition when the gamma radiations from the daughter products are being emitted in a location different from that of the parent uranium. In the decay chain of uranium almost all the gamma radiation emitted in the entire chain comes from the daughter product, bismuth-214. Bismuth-214 is separated from uranium by several long-lived isotopes that are chemically active and have different physical properties, often resulting in shifts in the location of bismuth- 214 relative to the parent uranium. In the United States orebodies exhibiting disequilibrium are a common occurrence and the use of a gross gamma log to delineate uranium orebodies can lead to errors. At present the solution to the disequilibrium problem is extensive coring followed by chemical analyses of the cores. There are several drawbacks in using this technique. First is the high cost of coring, the second is the fact that no results are available for days, or typically, weeks after the drilling is done. Thus for development work, coring and drilling must be done on a grid basis and many additional holes are cored to ensure that the entire orebody is mapped. Another disadvantage to cores is the fact that a small volume is sampled, the volume of the core itself. This leads to problems in the mapping out of the orebody when the ore de- posit is not very homogeneous. The PGT probe described in this paper is a new solution to the disequilibrium problem. Basically, the probe measures radiations that come almost directly from uranium itself. The first daughter of uranium, which is protactinium-234 (Pa-234), is only separated from uranium by a 24-day half-life and no disequilibrium problems build up in such a short time. The PGT probe measures the intensity of a one MeV gamma line emitted by Pa-234 and, using this information, calculates the concentration of uranium. The PGT probe is 24" in diameter and 12 feet long. The probe contains a microprocessor which passes the information to a larger minicomputer in the truck. All data is analyzed on site, and the results from a high speed printer are presented to the geologist. Data is also available on 9- track IBM compatible tape for further processing. The PGT probe output is linear with uranium concentration. The only correction factor is for borehole size, and that only becomes important in boreholes bigger than seven inches in diameter. Dead time is compensated in the probe itself and no problems have been encountered in ore zones up to several percent UjO8. In addition to the uranium assay, a conventional gross gamma log is plotted alongside. Grade thicknesses for zones above cutoff are calculated as well as disequilibrium factors. COMPARISONS During its commercial operation PGT logged a series of 18 holes that had been cored and assayed. All of the holes in this series were logged in normal operation by regular field operators. The time to log each hole was generally under an hour, and in typical operation a PGT logging truck will do between 7 and 8 holes a day. The results of the comparison of the PGT and the core assays are presented in a series of figures showing plots of the PGT assay, core analysis and gross gamma measurements. The first three figures show individual holes with the gross gamma plotted along with the core and the PGT assays. All three logs were from holes on the reduced side of a rollfront deposit in South Texas. In Figure 1 we see the two wings of the roll- front at 143 ft and 150 ft separated by a barren zone. The wings are well defined both by the PGT assay and the core. There is approximately a one foot shift which can be attributed to drilling errors. The gross gamma is showing a rather severe discrepancy, being considerably lower and not showing the barren zone. The grade thickness calcula-

Jan 1, 1980

By James Kemp

IN earlier years, the custom prevailed of regarding the anthracite basins as cases of folding with slight development of faulting. Folding is so pronounced and, in the eastern and western Middle Fields, at times so violent, that the inference was a natural one and led to the widespread impression that practically all the disturbances of the seams could be explained in this way. The cross-sections-and maps prepared forty or more years ago for the Second Geological Survey of Pennsylvania, by Mr. Ashburner under Prof. J. P. Lesley, exhibit little else than folds.1 So far as I can discover faults fail in the charts, except in one small case in the Henry Colliery near Plainsville on the outskirts of Wilkes-Barre. Some years ago, while spending a day or two in Wilkes-Barre, under the guidance of R. V. Norris, I looked over some recent and accurate cross-sections of a number of the large collieries and was deeply impressed with the peculiar behavior of some of the seams and the intervening shales. Thus, a seam might present a small, more or less overturned fold, rising 30 to 50 ft. (9 to 15m.) above its general course, and yet the movement would be taken up in the overlying shales, so as hardly to be noticeable in the seams next above or below. These and similar anomalies, especially when shown with the accuracy of engineer's surveys, possess great scientific and practical interest, bearing as .they do, not alone on coal mining, but on theoretical geology and the actual behavior of strata under great compressive stresses. In preparation for the semicentennial meeting of the Institute, an, effort was therefore made to secure some of the most interesting sections for presentation to the members. The collection of illustrations here shown is mainly due to, Mr. Douglas Bunting of the local committee, to whom and to the contributing companies acknowledgments are due.

Jan 1, 1922

By J. T. Ryan

POISONOUS, irritating, or explosive gases are found in almost every industry, and manufacturers of gas masks are called upon to provide gas mask protection for a great variety of conditions, such as operators in horseradish factories, fumigators of homes and ocean liners, and men engaged in the manufacture of tetra-ethyl-lead, the new motor fuel. The modern type of gas mask and respirator, to provide protection against all such industrial gases, is an outgrowth of the gas mask developed during the World War to protect the soldiers against the poisonous war gases. So far, it has been possible to develop ample mask protection from all known noxious gases and fumes present in atmospheres encountered in mines, metallurgical works, and chemical and other industries, so long as there is sufficient oxygen present to support the flame of an oil lamp. The most important development of the gas mask was in providing protection against carbon monoxide- which is the noxious gas that mining men are most concerned with and, in fact, is the noxious gas that man is most frequently exposed to. This paper will be con- fined largely to the discussion of masks for underground use in metal mines. Gases that contaminate the normal air in mines can be divided into two classes: those that are given off normally by the workings, and those that are produced in mine operation.

Jan 1, 1926

By AIME AIME

COAL occupied a large place in the technical sessions of the Institute at its annual meeting for in addition to three sessions specifically de- voted to coal the two sessions on mine ventilation and the two on ground movement and subsidence, which are reported under their own headings, were primarily concerned with coal. The first session on coal was a joint one with the Iron and Steel Division, on Wednesday afternoon, with F. H. Crockard and J. R. Campbell presiding as joint chairmen and the latter actually officiating. The principal topic of discussion was G. S. Scott's paper "Evaluation of Coal for the Making of Blast- Furnace Coke," which has been published as T. P. 159. The author made a brief statement of its con- tents to start the discussion and the chairman, after briefly reviewing it himself, called on C. A. Meissner to start the discussion. He briefly reviewed the economic factors in the use of coal for coke-making, saying that not only .does the removal of 1 per cent of ash from the coal reduce the cost of pig iron 12 or 13c. per ton, but it also permits coke of satisfactory structures to be made from a coal which otherwise could not be used. He stressed the importance of uniformity in blast-furnace fuel and discussed the benefit of mixing different coals as raw material for the coke oven and cited experience with Illinois coals.

Jan 1, 1929

By H. C. van Elst

Ultrahigh-speedphotographic and electronic meth-ods were applied to an investigation of details of brittle-fracture propagation in steel. The brittle fractures studied were obtained in steel plate with the aid of a Robertson apparatus. It was found that a brittle fracture proceeds by discrete steps ranging from 30 mm near the stop temperature to less than 2 mm at lower temperatures. The halting FROM prior metallographic observations of brittle fracture in steel' it could be concluded that the distribution of mechanical twins along a brittle fracture was similar to the distribution of mechanical twins induced by explosive deformation. It was therefore assumed that a running brittle fracture created stress waves, cf. Refs. 2-7. An emission of stress waves by a brittle fracture, however, seems only conceivable if the fracture propagates by discrete steps. For this reason a study of the details of times between successive steps drop in this tem-perature region from 20 usec to about 1 psec. The stepwise propagation mechanism is accompanied by an intermittent emission of stress waves of the order of 100 to 200 kg per sq mm. These stress waves seen1 to play an important role in the mechanism of brittle fracture as will be discussed. brittle-fracture propagation was undertaken to investigate the possible determination of the fracture steps and the emitted stress waves associated with the assumed mechanism. The more practical object of this work is the development of a test method for the determination of the ductile-brittle transition in small specimens. This has special advantages for the study of irradiation damage in steel. In this test method, which will be published in a following paper, the stress waves emitted by an actual brittle fracture are reproduced with explosive or electrical means and are then transmitted through small specimens at various temperatures. In the present paper only the results of the brittle-fracture study will be reported.

Jan 1, 1964

By G. G. Hancock, H. H. Johnson

Hydrogen gas at atmospheric pressure is shown to cause substantial embrittlement in a martettsitic high-stretzgth steel. Subcritical crack growth is observed at very lom stresses and with high growth rates. It is suggested that an adsorbed layer of hydrogen atoms at the crack-tip surface provides the damaging hydrogen. Oxygen in small quantity, as little as O.7 pct by volume, is shown to eliminate subcritical crack growth in gas environments caused by hydrogen or water vapor. However, dissolved oxygen in water has little or no influence upon crack-growth rates. Oxygen-stopped cracks may be restarted by water, or by hydvogen or water vapor if oxygen is removed from the environment. These observations are interpreted in terms of preferential adsorption of oxygen at the crack tip and the formation of an oxide barrier. RECENT investigations1-3 have demonstrated that environmental factors are frequently responsible for delayed failure in martensitic high-strength steels. The environment causes crack initiation from preexisting cracklike flaws at unexpectedly low stresses, often far below the uniaxial yield strength. The crack then propagates at a rate controlled by the environment and the crack-tip stress-field intensity; during this period crack propagation will cease if either the stress or the aggressive environment is removed, and this may be considered a definition of subcritical crack growth. Fracture occurs when the crack has grown to a critical length, such that the fracture toughness of the steel is exceeded. Several liquids are known to cause delayed failure, but water and water vapor are the most severely damaging of the environments investigated to date.'-3 It has been suggested that hydrogen produced during corrosion reactions may be the actual embrittling agent2 The severe embrittlement caused by water vapor inevitably raises the question as to whether other gas environments are damaging. Previous work4'5 has demonstrated that high-pressure hydrogen (2250 psi or greater) is an effective embrittling medium, as measured by such criteria as reduction in area, notch tensile strength, and time to failure. Moreover, the embrittlement was eliminated by the addition of small quantities of air or oxygen to the high-pressure hydrogen, but it was not influenced by additions of nitrogen or argon.4 In the present study attention is focused upon gas environments at atmospheric pressure, in particular hydrogen and oxygen. The influence of these constituents upon the initiation and growth of a crack from a pre-existing cracklike flaw in a high-strength steel was determined directly by the electric-potential method of monitoring crack growth. MATERIALS AND PROCEDURE The H-11 steel was supplied by the U.S. Naval Research Laboratory as 3 by 12 by 0.065 in. sheet specimens with 1-in. transverse center slots. The slot tips were finished by Elox machining to a radius of 0.001 in. or less. The yield strength was 230,000 psi; chemical composition and heat-treatment schedule are given in Table I. The experimental apparatus, precracking procedure, and incremental loading sequence have been described previously.3 In the only significant change, precracking was sometimes carried out by a hydrogen embrittlement and baking technique. All experiments were conducted at room temperature; the hydrogen gas environment was purified by a commercial palladium purifier. Crack initiation and propagation were followed by the electric-potential method,'-3 using a calibration that has been recently dicussed. Stress-field intensities at the crack tip were computed by the conventional Irwin frmula; the plasticity correction was negligible and therefore not included. EXPERIMENTAL RESULTS A striking brittleness associated with molecular hydrogen at atmospheric pressure is demonstrated by the data in Table I1 and Fig. 1, which indicate that subcritical cracks in hydrogen initiate at lower stress-field intensities and propagate more rapidly than in fully humid argon. Ki and Kf are the crack-tip stress-field intensities at initiation and termination of subcritical crack growth, respectively. Termination, of course, corresponds to fracture. In both hydrogen and humid argon Ki is less than Kf

Jan 1, 1967

By E. J. Kenaedy, E. H. Robie

THOUGH the fall meeting of the Coal Division was held in the heart of the anthracite section, at Hazleton, Pa., the bituminous industry was well represented also, and the two groups found much common ground for discussion. The' technical part of the program was confined to two sessions in the morning and afternoon of the first day, Friday, Oct. 14, the evening and the following day being reserved for field trips and social functions. The attendance more than met the expectations of those in charge of the arrangements; there seemed no hint of depression here.

Jan 1, 1932

By Leland Van Wert

IN 1888, Howard,1 working at the Watertown Arsenal on the tensile properties of ferrous materials at various temperatures, noted the curious fact that the stress-strain diagrams of low-carbon steels tested within a certain temperature range (200° to 350° C.) departed more or less from the normal regularity of such diagrams as secured by testing at either above or below these temperatures. This same jagged appearance of similar diagrams for steels has been observed by at least one other investigator, and de Forest2 has reported similar irregularities in the tensile testing of some nonferrous alloys. Recently again, this anomaly in diagram contour has been shown in a most striking fashion, apparently because of its accentuation by the method of testing employed, by Dr. Albert Sauveur.3 He described (for nonaustenitic steels) two quite distinct types of torsional stress-time diagrams: (1) those with a regular and smooth outline, derived normally by testing at temperatures above 300° C., or below 200° C. (as, for example, Figs. 4a or e); and (2) those presenting a decided "stepped" appearance, which are invariably produced when twisting is done within the 200° to 300° C. range (examples, Figs. 5a and b). The torsion test brings out so much more sharply (and convincingly) the irregularities occurring at 200° and 300° C. than does the tensile test that they can no longer be considered as resulting from simply idiosyncratic or accidental and inconsequential causes. Clearly, from the temperatures involved, the "stepped" type of diagram, or more accurately, the peculiar manner of response to torsional stress which manifests itself in the diagram, is an aspect of the "blue-heat" phenomenon. One's curiosity if, nothing else, prompts an inquiry as to the nature and significance of these "steps." What do they mean? What causes them? To these questions there are no completely satisfactory answers. The following experimental observations are offered as suggestions towards the solution of the problem.

Jan 1, 1931

By C. W. Goodale

THE motives behind the organization of the Bureau of Safety were twofold. First, there was the policy of the company toward its employees, which was one of fairness and consideration for their welfare and which entails the prevention of injuries; second, in order to prevent injuries, a study of their causes was essential, and this study could be made only by a thorough systematic classification of accidents, which required a special department to form and carry out the plans. The Bureau of Safety was organized to begin operation Jan. 1, 1914, but practically all of the first year was spent in collecting data, making plans, etc. This department is semi-independent of others and reports directly to the president and general manager. It consists of the president of the company and the managers of the following departments: Mines, Washoe Reduction Works, Great Falls Reduction Works, Coal Department, Lumber Department, B. A. & P. railway, and the chairman of the Bureau of Safety. Working under this group is the General Safety Committee consisting of the manager of mines, as chairman, the general superintendent, two assistant general superintendents, and the heads of the following departments: mechanical, geological, purchasing, sampling works, and framing plant, as well as the safety engineer. Operating under the General Safety Committee are the group safety committees, consisting of the Anaconda group of mines, Boston & Montana group of mines, zinc group of mines,.Washoe reduction works at Anaconda, B. & M. reduction works at Great Falls, coal department, lumber department and the B. A. & P. railway. Each of these group safety committees was in charge of the superintendent or manager of the group represented and the committee consisted of the foremen of the mines or works that the committee served, as well as the safety engineer.

Jan 2, 1922

By Leland Russell van Wert

In 1888, Howard,1' working at the Watertown Arsenal on the tensile properties of ferrous materials at various temperatures, noted the curious fact that the stress-strain diagrams of low-carbon steels tested within a certain temperature range (200" to 350" C.) departed more or less from the normal regularity of such diagrams as secured by testing at either above or below these temperatures. This same jagged appearance of similar diagrams for steels has been observed by at least one other investigator, and de Forest2 has reported similar irregularities in the tensile testing of some nonferrous alloys. Recently again, this anomaly in diagram contour has been shown in a most striking fashion, apparently because of its accentuation by the method of testing employed, by Dr. Albert Sauveur.~ He described (for nonaustenitie steels) two quite distinct types of torsional stress-time diagrams: (1) those with a regular and smooth outline, derived normally by testing at temperatures above 300" C., or below 200" C. (as, for example, Figs. 4a or e); and (2) those presenting a decided "stepped" appearance, which are invariably produced when twisting is done within the 200" to 300" C. range (examples, Figs. 5a and b). The torsion test brings out so much more sharply (and convincingly) the irregularities occurring at 200' and 300" C. than does the tensile test that they can no longer be considered as resulting from simply idiosyncratic or accidental and inconsequential causes. Clearly, from the temperatures involved, the "stepped" type of diagram, or more accurately, the peculiar manner of response to torsional stress which manifests itself in the diagram, is an aspect of the "blue-heat" phenomenon. One's curiosity, if nothing else, prompts an inquiry as to the nature and significance of these "steps." What do they mean? What causes them To these questions there are no completely satisfactory answers. The following experimental observations are offered as suggestions towards the solution of the problem.

Jan 1, 1931

By Robert H. Richards

If one holds up a prism, or wedge of glass, with narrow angle, say l° to 2O, and compares the transmitted image with the image seen above or below the prism, the former will be found to be thrown to one side by an amount varying with the angle of the wedge. Speaking of the two rays as the direct ray and the bent ray, we may say, that when the bisecting plane of the prism is at right angles to the line of sight, the angle between the direct ray and the bent ray will be constant for any given prism. If now we place a prism or wedge of glass in such a position that it half-covers the objective of a telescope, we shall obtain on looking through it two images of every object seen—one image by the direct ray, which comes through the unaovered half of the objective, the other which comes through the prism, and is the image by the bent ray. The angle of divergence of these two raps will be constant and unalterable, whether the telescope is directed to a near object, with its eye-piece at increased distance from its objective, or upon a ' distant object, with eye-piece nearer to the objective. That is to say, if the " throw " or apparent dislocation of the image is one foot in one hundred feet it will be two feet in two hundred, ten feet in a thousand, and so on. The usual form of stadia-telescope has at the focal point of the objective two spider-lines, placed at a definite distance apart and intended, let us say, to represent a throw of one foot in one hundred feet. But as the distance between lines remains the same, while the distance from the objective to the webs diflers with every variation in the distance of observed objects, it follows that the angle between the lines of sight which these two spider-lines define cannot be con stant, but must vary with every increase or decrease of distance be tween the instrument and the object viewed. If in Fig. 1 we represent three positions of the spider-lines by W1, W2, W3, and three objects corresponding to those positions by 01, O2, 0, at near, medium and distant positions, we see at

Jan 1, 1892

By G. F. Huff, G. R. Bailey, J. H. Richards

An improved bomb-sampling technique for obtaining samples for oxygen analysis from liquid steel is described. Analyses of samples taken from open-hearth furnaces by the improved method show sufficient agreement with laboratory data to indicate the accuracy of the method is better than that of other existing sampling methods. THE bomb-sampling method of determining the oxygen content of a liquid-steel bath was studied by obtaining and analyzing more than 200 samples from normal open-hearth heats. Of these samples, about 60 were obtained with a bomb of conventional design;' the remainder were taken with a somewhat modified bomb designed to give greater protection against slag contamination. In the new device, the contacting faces of the cast-iron mold halves are machined so that they fit closely; the opening at the top of the bomb is covered with a thin steel cap; and the top of the bomb is further covered with a wood block held in place by heavy steel wire. After the bomb has passed through the slag layer and has entered the steel bath, the wire melts and the wood block floats to the surface. Thereafter, the steel melts through the thin cap and flows into the bomb cavity where it is deoxidized with aluminum wire. An assembled bomb, ready for sampling, is shown in Fig. 1. To standardize sampling procedure, the samples were usually taken through the center door and at the bottom of the furnace; that is, the bomb was on the bottom when the metal cap melted. After each addition to the furnace, at least 20 min elapsed before a sample was taken. The oxygen contents of all the samples were determined by using the vacuum-fusion method, two or more specimens from each sample being analyzed. The specimens were cubes of metal cut from a region in the interior of the bomb sample, as shown in Fig. 2. Drillings for carbon analysis were obtained immediately above the oxygen-analysis region. Reproducibility of Results In determining the reproducibility of the results obtained with the modified bomb, the following four factors were studied: 1—variation in the oxygen concentration of duplicate specimens taken from a single sample; 2—variation in the oxygen concentration of duplicate samples taken in quick succession: 3—effect of the amount of aluminum wire

Jan 1, 1953

University of Kansas, Department of Mining Engineering, Lawrence, Kansas Professor C. M Young The Department of Mining Engineering of the University lists two publications issued separately from the State Geological Survey: Engineering Bulletin 11, A chemical survey of the natural gases of Kansas and Oklahoma, by H C. Allen and E E Lyder. Engineering Experiment Station Bulletin 13, Kansas coal, by C. M. Young and H. C. Allen.

Jan 1, 1933