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By T. S. Fuller

The work of D. J. McAdam, Jr.1,2 at the U. S. Naval Engineering Experiment Station, Annapolis, Md., on what has been called by him "corrosion-fatigue" has focussed the attention of the engineering profession in general, and of those interested especially in the study of corrosion in particular, on the importance of making tests which will indicate as nearly as possible what can be expected from a given material in service. Pitting is unquestionably the chief agent operating so tremendously to reduce fatigue limits, but in the light of previous work3, 4, 5, 6, 7, 8 it is fair to assume that absorbed hydrogen resulting from the action of the corroding medium upon steel may, under certain conditions, have a perceptible influence. The experiments described in this paper deal more precisely with stressless corrosion, or "prior-corrosion fatigue,"9 and have been carried out to test such an assumption, to segregate, if possible, the effect of pitting from that of absorbed hydrogen, and although very preliminary in nature they indicate results which are striking.

Jan 1, 1929

By T. S. Fuller

THE work of D. J. McAdam1,2 at the U. S. Naval Engineering Experiment Station, Annapolis, Md., on what has been called by him "corrosion fatigue" has focussed the attention of the engineering profession in general, and of those interested especially in the study of corrosion in particular, on the importance of making tests which will indicate as nearly as possible what can be expected from a given material in service. Pitting is unquestionably the chief agent operating so tremendously to reduce fatigue limits, but in the light of previous work3, 4, 5, 6, 7, 8 it is fair to assume that absorbed hydrogen resulting from the action of the corroding medium upon steel may, under certain conditions, have a perceptible influence. The experiments described in this paper deal more precisely with stressless corrosion, or "prior-corrosion fatigue, "9 and have been carried out to test such an assumption, to segregate, if possible, the effect of pitting from that of absorbed hydrogen, and although very preliminary in nature they indicate results which are striking.

Jan 1, 1929

By Robert B. Bossler, Parke A. Dickey

The presence of connate water in oil sands is of far greater practical significance in secondary oil-recovery operations than it is in primary operations. The percentage saturations of oil, water, and gas in a depleted field determine whether it will be economically possible to recover oil by secondary methods, and whether water-flooding or gas-driving, or either, will be successful. It is suggested that economic recovery of oil by secondary water-flooding can occur only when a rich bank of oil is formed by the encroachingm water. If the sand has a greater effective permeability to water than it has to oil before flooding, a bank will not be formed, and water-flooding will not be successful, although gas-driving may be. Published results of laboratory work indicate that the effective permeability of a sand to oil and water depends primarily on the saturation of the sand by these phases. They also indicate that a small difference in relative saturation produces a large difference in effective permeability to the phase in question. There thus exists a critical range of saturations, wherein a small change in oil and water content of the sands will make water-flooding possible or impossible. In gas-drive operations the water saturation is less critical but no less important. The presence of connate water in a sand increases the proportion of the residual oil that may be recovered by gas drive. Sands containing oil saturations too low and water saturations too high to make water-flooding possible can often be subjected to gas drive with economic recovery of oil. The results of laboratory work on test samples that do not contain water cannot be applied to normal field operations. More tests on cores containing water as well as oil are desirable, and the improvement of coring technique is necessary. However, sufficient data are already available to enable an operator to use core data intelligently in estimating the chances of a secondary oil-recovery program. Introduction In recent years laboratory work has led to a much better understanding of the principles of oil-reservoir performance. The general principles of the expulsion of oil from sandstone by gas or water were developed by geologists of the Second Geological Survey of Pennsylvania in the 1870lsl but only recently has the mechanism of gas or water drive been intensively investigated. Most published articles have large the facts established in the labora tory to the primary production of oil from flush fields- This Paper is not based on any new observations, but is an attempt to apply some of the conclusions obtained in the laboratory and described in the literature to the recovery of oil from depleted pools by secondary methods. One of the most important factors that determine whether or not a secondary-recovery operation is economically successful is the ratio of injected fluid to oil recovered. This ratio may be expressed as the over-all or cumulative gas-oil ratio if gas is the driving medium, or water-oil ratio if water is the driving medium. Recent theoretical and experimental work has shown that the relative amounts of

Jan 1, 1944

By Parke A. Dickey, Robert B. Bossler

The presence of connate water in oil sands is of far greater practical significance in secondary oil-recovery operations than it is in primary operations. The percentage saturations of oil, water, and gas in a depleted field determine whether it will be economically possible to recover oil by secondary methods, and whether water-flooding or gas-driving, or either, will be successful. It is suggested that economic recovery of oil by secondary water-flooding can occur only when a rich bank of oil is formed by the encroachingm water. If the sand has a greater effective permeability to water than it has to oil before flooding, a bank will not be formed, and water-flooding will not be successful, although gas-driving may be. Published results of laboratory work indicate that the effective permeability of a sand to oil and water depends primarily on the saturation of the sand by these phases. They also indicate that a small difference in relative saturation produces a large difference in effective permeability to the phase in question. There thus exists a critical range of saturations, wherein a small change in oil and water content of the sands will make water-flooding possible or impossible. In gas-drive operations the water saturation is less critical but no less important. The presence of connate water in a sand increases the proportion of the residual oil that may be recovered by gas drive. Sands containing oil saturations too low and water saturations too high to make water-flooding possible can often be subjected to gas drive with economic recovery of oil. The results of laboratory work on test samples that do not contain water cannot be applied to normal field operations. More tests on cores containing water as well as oil are desirable, and the improvement of coring technique is necessary. However, sufficient data are already available to enable an operator to use core data intelligently in estimating the chances of a secondary oil-recovery program. Introduction In recent years laboratory work has led to a much better understanding of the principles of oil-reservoir performance. The general principles of the expulsion of oil from sandstone by gas or water were developed by geologists of the Second Geological Survey of Pennsylvania in the 1870lsl but only recently has the mechanism of gas or water drive been intensively investigated. Most published articles have large the facts established in the labora tory to the primary production of oil from flush fields- This Paper is not based on any new observations, but is an attempt to apply some of the conclusions obtained in the laboratory and described in the literature to the recovery of oil from depleted pools by secondary methods. One of the most important factors that determine whether or not a secondary-recovery operation is economically successful is the ratio of injected fluid to oil recovered. This ratio may be expressed as the over-all or cumulative gas-oil ratio if gas is the driving medium, or water-oil ratio if water is the driving medium. Recent theoretical and experimental work has shown that the relative amounts of

Jan 1, 1944

Activity with the legislation proposing to liberalize War Minerals Relief Act has now started before the Committee on Mines and Mining of the House. They are considering House Joint Resolution No. 170, which brings out the fact that war minerals claims in excess of $15,000,000 had been filed but that a considerable portion of the claims are being denied because of the Attorney General's. interpretation of the Act. The resolution states that it was the intention. of Congress in passing the War Minerals Relief Act "that all producers of the minerals mentioned should be repaid such sums as they are in equity and good faith entitled." The Attorney General's opinion is that the request or demand must have been made on the claimant direct. The resolution provides. that all claimants "who in response to any personal, written or published request or demand from any of the Government agencies-mentioned-in said Act in good faith expended money in producing or preparing to produce any of the ores or minerals named-therein *-*-* and have heretofore filed their claims within the time and-in the manner prescribed in said Act" are to be reimbursed for the n t-losses-incurred.

Jan 12, 1919

By Reno Sales

INTRODUCTION. THE geology of Butte possesses especial interest on account of the magnitude of the ore deposits, their extraordinary richness and persistence in depth. Since its discovery in the early 60's the district .has yielded, in round numbers, 6,000,000,000 lb. of copper, 260,000,000 oz. of silver, 1,250,000 oz. of gold, and a large but not definitely known number of pounds of zinc. This enormous metal production has been derived from an ore tonnage estimated roughly at 65,000,000 tons. At the present day, most of the important mine shafts have reached a depth of. 2,400 ft., while several are more than 3,000 ft., deep. At these-great depths rich bodies of copper ore are being exploited, showing no diminution in metal content as compared with the ores of the higher levels. The present (1913) daily rate of production is approximately 14,000 tons, of which 13,250 tons may be regarded as copper ore, although a small percentage of this is minable only because of the presence of

Jan 8, 1913

By Marling J. Ankeny

MINING research in the U. S. today is indeed complex, whether it involves the Government, a small private concern, or a large one. And it promises to become more so, despite great advances already made in developing equipment and technology. The U. S. Bureau of Mines is committed to place greater emphasis on mining research as expressed in a recent policy statement to Congress on the "Long Range Minerals Program," by Secretary Fred A. Seaton, quoted above.

Jan 1, 1958

By T. Egleston

Although the success of metallurgical operations depends so largely on the possibility of finding proper refractory materials, which enter so prominently into the cost of their operations, it can hardly be said that our knowledge of them is in a very satisfactory condition, or even that we know very much about them, beyond a few facts which have been gathered through their use. Experience, as a general thing, is an excellent master, but the requirements of

E. B. WILSON, Scranton, Pa. (written 'discussion *).-Prof. Young's paper shows another application of electricity in solving problems in coal mining, and suggests that it may be possible to utilize the data he has collected in developing an electric firedamp detector. If electric lamps are to be adopted in gassy coal mines, the use of an electric firedamp detector becomes almost imperative, for safety lamps and electric lamps in the same mine are not always conducive to safety, and Liveings electric firedamp detector, is too cumbersome to meet with general approval. Three well understood facts are verified in a new way by Prof. Young's experiments: - 1. The temperature at which methane ignites. 2. The more inflammable gas present in an atmosphere, the hotter will be the flame, and the longer the cap in a safety lamp. 3. As the temperature at the source of ignition varies, the length of the gas-cap flame varies. Prof. H. B. Dixon collaborating with Mr. H. F. Coward, some years ago, made experiments on the ignition of various gases to find the tem-perature of their kindling points.1 From the results of their experiments, the writer has culled the ignition temperatures of some hydrocarbon gases, and has tabulated them with other data, in Table 1.

Jan 10, 1919

By Harold R. Bradford

EXPANSION initiated during and after the war has placed industrial plants in new areas and increased reduction and manufacturing facilities in communities already established. With added expansion interest has grown in possible area contamination from waste products. Evolved flue waste contains many chemical contaminants that may or may not cause concern; however, atmospheric pollution has always been a problem to industrial communities. For some time effects attributed to small quantities of compounds of fluorine in various waste gases have been studied by industrial, medical, agricultural, and associated interests.1'2 Aside from an article by Churchill, Rowley, and Martin in 1948," little has been published on the subject of fluorine in coal except by foreign investigators. The first indication of fluorine compounds in coal was noted in England in 1934 by R. Lessing,4,5 who found that the presence of fluorine in Midland and West County coals was definitely established by etching of glass and by severe corrosion of porcelain fillings in a gas works scrubber. Etching of glass in a direct contact annealing kiln initiated research, and in 1944 four papers were published by H. E. Crossley,6-9 giving results of investigations of fluorine in coal of England by the Fuel Research Board, Department of Scientific and Industrial Research. These investigations studied methods of determining fluorine, the quantities present in various coal deposits, the geographical distribution of fluorine in British coals, occurrence of fluorine in minerals associated with coal, amounts of fluorine compared to other constituents of coal, the nature of fluorine compounds, and industrial significance of fluorine in coal. It was shown that British coals contain from 5 to 200 ppm of fluorine, which is probably present as fluorapatite [Ca10F2(PO4)6], often written as [3Ca3P2O8.CaF2]. The fluorapatite is intimately associated with shale in some coals and can often be separated from these coals along with the shales. H. E. Crossley8 also reported no correlation between the amounts of chlorine, sulfur, or ash and the amount of fluorine in different coals. He found, however, a relationship between the content of fluorine and phosporus in many British coals. Thus it should be possible to anticipate likely fluorine-rich coals from existing data giving phosphorus content. Behavior of the fluorine compounds of coal was compared with that of 12 fluoride-phosphate minerals in sink-float separations and solvent ex-

Jan 1, 1958

By Wilhelm Rohn

IN discussing the influence of a content of gases on metals and alloys we should probably first consider the physical and chemical conditions under which these gases may be present. By a chemical analysis, such as the total extraction of gases from the liquid metal by melting in a graphite crucible in vacuo, we find only the sum of gaseous chemical elements contained in the metal in any form and no reference is made to the special form under which they have been present previously. CONDITION OF GASES IN METALS In considering gases . in metals we may first turn our attention to gases simply dissolved. Because the solubility of almost any gas decreases suddenly at the freezing point, most of them are released during solidification, developing rise of ingots and blowholes. If only a little gas is dissolved in the molten metal the size of such blowholes may be miscroscopical, or even submicroscopical, resulting in a certain reduction of the notched-bar impact test values. Hydrogen is believed to become less soluble as the temperature is lowered and therefore increasing quantities of this gas may be evolved during cooling between the freezing point and room temperature, leading to unsoundness of the ingot at weak spots; i.e., at the grain boundaries. This gas at the grain boundaries probably is present at high pressure and therefore impairs the mechanical properties to a degree similar to that found in the hydrogen embrittlement of copper. Usually we may trace such gases by observing rising ingots, or at least by the formation of a characteristic pattern of small grooves upon etching.

Jan 1, 1932

By George Comstock

THESE notes should be considered as a further discussion of Mr. S. W. Miller's paper on "Some Structures in Steel Fusion Welds."1 In that paper and the resulting discussion; several conflicting opinions were expressed as to the identity of the needles or small crystals present in oxyacetylene and electric welds. An interesting specimen of an electric weld examined by the writer seems to afford new evidence regarding the needles, that may be worth presenting at this time. The specimen consisted of a piece of 3/8 -in. (9.5-mm.) steel plate, about 2 ¼ by 1 ¾ in. (5.7 by 4.5 cm.) in size, on which some iron had been deposited by arc-welding to a depth of about 3/16 in. (4.7 mm.). The weld appeared to be a very good one, with no noticeable break or boundary between the plate and the deposited iron. Sections for microscopic examination were cut in three planes at right angles to each other through the deposited metal, two of these sections also extending through the steel base. After polishing in the usual way, the microscope showed that the deposited metal was full of very small, round, gray, oxide spots, while the steel plate contained quite a number of alumina inclusions and a little slag. The sections were etched with nitric acid in ordinary alcohol, and structures similar to those described by Mr. Miller were then displayed. Fig. 1 shows the typical appearance of the deposited metal, which was quite uniform in all three of the planes examined. The round dark-gray spots are oxides, and the pale angular crystals are evidently what, Mr. Miller called cementite and Mr. Jeffries martensite, while Dr. Ruder and Prof. Boylston suggested that they might be nitride. The boundary between this structure and the steel base was sharply defined under the microscope. Fig. 2 shows the structure of the plate just under the weld; this is almost martensitic and resembles a coarse-grained casting. This coarse cast structure soon became finer as the distance from the weld increased, finally, becoming very fine, with numerous small particles of sorbite. This very fine structure, shown in Fig. 3, became coarser in turn and finally merged into the original normal structure of the steel plate, shown

Jan 1, 1919

By AIME AIME

THE World. Engineering Congress closed as it opened, with a brilliant and dignified ceremony. On Oct. 29, 1929, there were hearty speeches of welcome and of hope for the successful issue of this international gathering; on Nov. 7, the farewells were even more heartfelt expressions, and anticipation gave place to, realization. H. I. H. Prince Yasuhito of Chichibu, who had graciously opened the Congress; was unavoidably absent at the closing ceremony, being on duty with his command at the Army maneuvers, so that the principal speech was made by the President of the Congress, Baron Furuichi. The outstanding statistics of the meetings were: an over-all attendance, delegates and members, of 800 from overseas and 2800 Japanese 83 sectional meetings, all. meetings having practically capacity attendance, this being especially true of Section 11, mining and metal¬lurgy, where standing room only was commonly the rule; and 780 papers were presented, in full or in abstract or by title. H. I. H. Prince Chichibu attended each section on Oct. 31. The large attendance of Japanese students was notable at most sections.

Jan 1, 1929

By W. H. Jr. Meyer

Although an aerial photograph is not a map, most of the information that is necessary for compiling a map is recorded in the photograph provided some form of radial-line method is used to determine the true position of images. The slotted-templet method, which is based on the well-established radial-line principle, has made it possible to construct accurate mosaic maps at a cost comparable with that formerly charged for the average mosaic. It makes possible the securing of these results with far less ground control, which is always expensive. It has expanded widely the possible use of aerial photographs for mapping. ALTHOUGH a vertical or oblique aerial photograph is not a map, most of the information that is necessary for compiling a map is recorded in the photograph. Some ground controls or data are needed, the number and accuracy to be governed by the mapping method to be used and the scale and final accuracy desired in the finished map.

Jan 1, 1939

By A. J. Miles, A. D. Topping

in this paper, the theory of elasticity has been applied to the rock about a deep well, It is assumed that the rock has a modulus of . elasticity and a Poisson's ratio and that the theory of elasticity applies. It is necessary to know or assume the state of stress existing in the rock before it is penetrated by the well drill. The application of this theory indicates that stress concentration of shear, tensions, and compressions about the bore hole are of a high order. This is particularly true when a horizontal compressive stress exists in one direction only in the formation before drilling. If such an initial state of stress exists before drilling, then the rock will have stress concentrations of both tension and compression at the same elevation and of such magnitude that failure of the rock is likely. Accompanying these is a shearing stress of large proportion which is likely to produce spalling of the well walls. Internal pressure applied to the well bore will relieve the extreme compression but not the tension and has little effect upon the shear. Plastic deformation of the rock through a geological time tends to mitigate the stress concentrations. IntroductioN It has long been known that the stresses about holes and re-entrant corners of elastic solids under the influence of loads are different and generally more intense than those imposed upon the body else- where. Stress concentration at a re-entrant corner can be reduced by increasing the radius of the fillet at the corner. Stress concentration at the end of a crack in a plate undergoing either tension or compression Can be relieved appreciably by drilling a hole at the very end of the crack. Also, stresses can be increased in an elastic body in tension or compression by making a hole in it. The stress concentration is greatest at the edge of the hole. Considerable knowledge of the stresses which exist about the bore hole of a deep well may be had by applying our knowledge of engineering mechanics; or more particularly the theory of elasticity. It is, of course, necessary to make the assumption that the rock is elastic and behaves as an elastic solid, that is, that it obeys Hooke's law, has a modulus of elasticity, and a Poisson's ratio. It is also necessary to know, Or assume, the state of stress which exists in the rock prior to the penetration of the drill. With this knowledge it is possible to compute the stresses about the bore hole. The problem can be simplified by considering several simple cases separately and then by applying the principle of superposition to solve the more complex cases which are made up of the simpler ones. Case i—Rock Strata in Compression Penetrated by a Hole This case was first worked out by G. Kirsch* for structural material, but applies equally well to a horizontal rock strata in a state of in in one direction

Jan 1, 1949

By C. N. J. Wagner, E. N. Aqua

Dilute Fe-Si alloys (0 to 5 wt pet Si) were cold-worked by making filings at room temperatuve. The analysis of the broadening of the X-vay powdev pattern peaks yields anisotropic particle sizes normal to the (110), (100), and (112) planes which are a consequence of deformation faults (probability a) and twin faults (probability p). The combined fault probability (1.5a +ß) increases from 0.01 in pure iron to 0.02 in Fe-5 pct Si. The root mean square stvains vary with crystallographic ovientation due to elastic anisotropy of the alloys, and increase from about 0.0035 in pure iron to 0.005 in Fe-5 pct Si measured in the [100] direction. Assuming that deformation and twin faults occur with equal probability, the X-ray data would imply that the stacking-fault energy does not change upon alloying. THE crystallographic aspects of the plastic deformation of dilute Fe-Si alloys has been studied many times since the observation of glide band structures by Barrett et a1.l These glide bands were much straighter than the wavy bands observed by Gough2 in unalloyed iron nearly 40 years ago. This difference in the morphology of the slip band structure has been verified many times, most recently by replication electron microscopy3 and dislocation etch-pitting methods.4,5 These observed differences in deformation behavior have been considered to result from the degree of cross slip that occurs in pure iron and in the Si-Fe alloys. The lowered tendency for cross slip would result from a lowering of the stacking-fault energy of iron by the silicon alloying addition. Experimental evidence for this lowered stacking-fault energy in the Si-Fe alloys, obtained with transmission electron microscopy, is the observation of dissociated dislocations in Fe-6 pct si6 and Fe-3 pct Si alloys,7 and the observation of sharply defined cellular substructures in Fe-3 pct si6,7 compared to the more diffuse substructure in zone-refined iron.' The activation energy for recovery of cold work is greater in the Si-Fe alloys than it is in pure iron, indicating that cross slip has become a more difficult process.9 The purpose of this investigation is to determine the change in stacking-fault probability from the broadening of powder pattern peaks in dilute silicon-in-iron solid solutions, when cold-worked at room temperature. The knowledge of the stacking-fault probability and the dislocation density, both of which can be deduced from line-broadening analysis of two orders of reflections from (110), (200), and (112) planes, will permit us to calculate the change in stacking-fault energy upon alloying silicon into iron. Previous X-ray investigation of cold-rolled Fe-5 wt pct Si (100)[001 ] single crystals did not reveal any line broadening, whereas cold-rolled Fe-3.1 wt pct Si (001) [110] and (001)[100] single crystals10 showed line bro2dening as a consequence of small particle sizes (-200A) and root mean square strains (-0.25 pct), which are comparable to those found in cold-worked iron filings.11 EXPERIMENTAL PROCEDURE A series of five Fe-Si alloys containing nominally 1 to 5 wt pct Si and pure iron were cold-worked by making filings at room temperature. The actual silicon content deviated at the most by +0.1 pct which is of no significance in the present study. The carbon contents of these materials were less than 0.02 pct. The X-ray diffraction patterns were measured with molybdenum, cobalt, and iron radiation using a GE and a Philips diffractometer. The (110)-(220), (200)-(400), and (112)-(224) pairs of reflections were

Jan 1, 1968

By W. G. Bearden, G. C. Howard, J. W. Spurlock

An investigation of the factors af-fec.ting the inter-zonal flow of fluids in the casing-wellbore annrc1rt.s of an oil or gas ivell is presented Laborntory tests revealed that failure of the caring-cement bond allows communi-cation of fluid at pressure differentials near 1.000 psi. Perforating with a 11011011: carrier gun does not shatter or crack the cement sufficiently to allow communication through these cracks and does not seriously affect the casing-cement bond failure pressure. The pressure to cause communication at the casing-cement bond can he increared to 3,000 psi by. limiting pipe deformation during cementing and subsequent operations. Communication can be prevented, however. up to pressures sufficient to cause the cement to fail or the casing to col-lapse, by attaching to the casing a seal ring of deformable ruhber molded between two steel flanges. When installed, one flange is attached rigidlv to the casing to serve as back-up for the gasket While tile other flange is movable. To date, these gasket seal rings have been field-tested in 27 Wells. Althotrgh communication has been noted in two wells, inter-zonal flow has been prevented in other wells in the same area by installing more seal rings between the communicaring zones. INTRODUCTION The inter-zonal flow of fluids behind casing cemented in oil wells during normal production or stimulation operations is a major operating problem. If it cccurs during production operations. it can seriously limit the pressure to which a reservoir may be depleted without harmful invasion of unwanted fluids. If it occurs during stimulation operations, it may preclude the possibility of stimulating the desired zone. This communication can be caused by failure of the bond between the casing and cement, failure of the bond between the cement and formation, or failure of the cement itself. This paper presents the results of an investigation of factors affecting com-munication at the casing-cement bond and methods which aid in preventing it. LABORATORY INVESTIGATIONS The laboratory tests performed in this study were divided into three phases. The first phase consisted of tests to determine if perforating would shatter and crack the cement sheath so severely that communication would occur through the cement itself. The second phase consisted of tests to determine more precisely the cause for the casing-cement bond failure. The third phase consisted of tests to evaluate the effectiveness of various de-formable seals attached to the casing in preventing communication. EFFECT OF PERFORATING, The effect of perforating was invest~gated in tests performed with apparatus shown on Fig. 1. Cement was poured into the annulur space hetween 5%-in. casing and 8%-in. casing and allowed to cure for 72 hours. The apparatus was then perforated with a hollow carrier gun containing eight duPont 26-A shaped charges. Bull plugs were placed over the perforations in the 8 5/8-in. casing and hydraulic pressure was applied inside the 5 1/2i-in. casing. The pressure to cause fluid communication past the cement sheath was observed and termed the "bond failure pressure". Several different cement compositions were included in these tests, the results of which are shown in Table 1. In Tests 1 through 4 of Table 1, bond failure occurred at- the inter- .

Jan 1, 1966

By C. Y. Wang

China now leads the world in antimony production, having contributed during recent years something over 60 per cent. of the world's production. The history of the antimony industry of China dates back to 1897 when the Tai Shing Co. was formed, under contract with the Hunan Bureau of Mines, for the smelting of the ore to crude; and in 1908 the Wah Chang Mining & Smelting Co. was formed for the smelting and refining of the ore and crude to regulus. The writer was then asked to take charge of the erection and control of this first plant for regulus production in China and has, since then, been more or less connected with the antimony industry in this country. This paper contains the results of many years' experience in connection with the Wah Chang Mining & Smelting Co., Changsha; the Pao Tai Mining & Smelting Co., Wuchow; the Loong Kee Smelting Works and the To-Cheng Smelting Works, Hankow; as well as information gathered from various other small smelters, scattered in different parts of the Provinces of Hunan, Hupeh, Kwangsi, and Kwangtung. An idea of the growing importance of regulus production in this country can be gleaned from the fact that, within a period of about 8 years, the export of regulus from Hunan alone jumped from 3 tons in 1908 to about 6000 tons in 1915; that a production of about 23,000 tons of regulus per year could easily be effected from all the smelters, as tabulated below, most of which were erected a year or two ago under the stimulus of the war booms, if the price at Hankow were to stay somewhere about $900 (Mexican) per ton, half of what it was at its height, thus enabling the utilization of ores from the hinterlands of the provinces; and even under the present ruling of prices and the closing of the less favored smelters, the production of regulus should not be less than 12,000 tons per year.

Jan 1, 1919

By R. T. Murrill

BLOCK-SIGNAL and dispatching systems have been in use on surface railways for years, but only recently have they been applied to underground mining conditions. Formerly, all ore was moved underground by hand tramming; the surface openings were numerous and fairly close to the ore being mined. As the tramming distances increased, animals were brought into service. Then came the locomotive, and since its introduction, haulage lines have gradually been reduced to fewer levels and to fewer surface openings until more than 20,000 tons are being handled daily on one level in some of the larger mines. Under the, se conditions many trains must use the same-tracks, and signal systems have become necessary. In some cases it has been found more advantageous to use train dispatchers than to install signal devices. The dispatcher may be simply a flagman at a busy point or he may have mechanical signals to operate at more distant points. At the inspiration mine, Inspira-tion, Ariz., the station is equipped with a switch-con-trol board, whereby the dispatcher throws electrically all track switches in a certain block, which gives him complete control over all trains passing through that block. In a few cases, dispatcher stations are established in connection with a signal system.

Jan 2, 1922

By E. V. Potter, H. C. Lukens

THE volume of hydrogen released from electrolytic manganese at various temperatures and pressures was determined in a previous investigation1 as part of a study to determine the most practical procedure for removing the hydrogen from electrolytic manganese metal. No attempt was made to determine the absolute volume of gas in the metal at any temperature and pressure; the volume of gas released showed only the variation in solubility with temperature and pressure. The results were very similar to those obtained by Sieverts and Moritz.2 Both sets of data show a minimum solubility between 500° and 700°C., but they differ in certain respects; on cooling from 500°C., our results showed an increase in solubility of about 7 C.C. as compared with an increase of 34 C.C. per 100 grams shown by Sieverts. Furthermore, the transition temperatures, as indicated by sharp breaks in the solubility curves, did not agree well with Sieverts' data. This information was of secondary importance in the earlier investigations, and the solubility at low temperatures and the transition temperatures were subject to considerable error. There- fore, a subsequent investigation, reported in this paper, was made to measure the absolute solubility at temperatures from room temperature through the melting point and make more accurate observations of the transition temperatures. APPARATUS AND METHOD The apparatus and method were essentially the same as those described in the previous work,1 as shown in Fig, I. At high temperatures, the small tube containing the thermocouple in the sample container A frequently broke off, so for some of this work the thermocouple was placed outside the sample container and protected by a quartz tube of about the same wall thickness as the sample container. No significant difference was found in the transition temperatures obtained in the two ways. The automatic temperature controller was used in these tests in the regions where there was little change in solubility with temperature. In the neighborhood of the transition points a continuously variable autotransformer was used instead of the automatic controller, and the power input to the furnace was adjusted so that the temperature increased or decreased at a very slow, uniform rate through the transition range. This procedure was followed because the temperature oscillations produced by the controller were too great compared with the transition range, and the transition points determined under such conditions were less accurate. ABSOLUTE SOLUBILITY Procedure and Results The absolute solubility of hydrogen in manganese could be determined most

Jan 1, 1946