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By C. W. A. Newey

I would like to make the following points in connection with the studies of the deformation of NiAl reported in the recent paper by Wasilewski, Butler, and Hanlon. 1) Much of their paper is concerned with demonstrating that slip occurs on either {110)(001) or {100)(001) systems. In their discussion they state "the existence of (001) as the basic slip direction can thus be considered established." This fact was established by the earlier studies of Ball and Smallman.32 Ball and Smallman also concluded that the slip plane was of the type (110) and they showed that cross slip or pencil glide on orthogonal (110) planes could produce macroscopic slip on planes of the (001) zones, e.g., (100). Wasilewski et al. refer to this paper by Ball and Smallman but not in connection with the slip system determinations. 2) Wasilewski et a!. eliminate the possibility of (111) slip in NiAl on dubious grounds. Their statement that ('the very high yield strengths of the (100) oriented crystals", in which (001) slip is constrained, "immediately ruled out the possibility of {110)(111) slip" cannot be accepted unequivocably; it would be reasonable if the crystals were completely brittle but they are not, as Wasilewski et al. and others33734 have shown. Their elimination of the possibility of (111) slip in a crystal compressed along [227] is misleading since there is no obvious reason why (111) slip should occur in a crystal of this orientation. In fact, from an analysis of the macroscopic surface markings on deformed (100) stoichiometric crystals, Pascoe and Newey34 have deduced that slip occurs on systems of the type {211)(111) and {321)(111). 3) Polycrystalline NiAl is known to undergo general deformati~n.Having emphasized that general deformation is impossible if only (100) slip occurs, it is a pity that Wasilewski et al. do not attempt to account for the disagreement between theory and their experimental results. Of course, (111) slip can provide the additional independent systems required for general deformation.

Jan 1, 1969

By A. C. Dorenfeld

ORES of the Mammoth mining district, some 45 miles northeast of Tucson, Arizona, are treated by Mammoth-St. Anthony, Ltd. The ores now treated come from a complex system of veins and faults, comprising three mines, in close proximity: The Mohawk, Mammoth and Collins. The ore treated in the past was oxide ore, which contains economic amounts of gold, silver, lead, molybdenum, and vanadium (as wulfenite and vanadanite). The lead-zinc sulphide ore has never been treated before. THE ORE The sulphide ore contains galena, sphalerite, marmatite, pyrite and some chalcopyrite, covellite, chalcocite and bornite, as well as small amounts of gold and silver. The value of the ore is principally in the lead and zinc content. The lead-zinc sulphides are substantially liberated at a minus 65-mesh grind. However, a large part of the chalcopyrite and other copper minerals is not freed, but remains as pin points on the sphalerite. Economically, the copper is unimportant. The gangue is a rhyolite granite, with very little limestone. There is no molybdenum or vanadium in the sulphide ore. HISTORY OF SULPHIDE TREATMENT Test work on samples of the sulphide ore was conducted by several equipment companies, the Arizona Bureau of Mines and the company's laboratory. Results of this test work indicated that for some reason, which at the time could not be explained, recoveries would be only about 65 per cent lead and 50 per cent zinc. Not-withstanding this, because of the nation's need for metals, the management built a 150-ton treatment plant. The mill was started in June 1942. During December 1942, using the standard method of treating lead-zinc ore, the monthly results were as shown in Table 1. These results were poor. Too much lead was in the zinc concentrate, and too much zinc in the lead concentrate. [ ] It should be noted here that prior to December attempts were made to depress the sphalerite with large and varied amounts of cyanide, zinc sulphate, and sodium sulphite with poor results.

Jan 1, 1944

Through the generosity of Sir Robert Hadfield, Honorary Member, the Directors of the American Institute of Mining Engineers are enabled to announce the Hadfield Research Prize of $1,000 for the best contribution to the publications of the Institute upon the general subject of The Different Forms and Combinations of Carbon with Iron, including those in Iron Alloys. The prize will be awarded at the Annual Meeting of the Institute in February, 1916, to the best paper upon this subject which is presented to the Institute before Nov. 1, 1915, provided such paper is deemed worthy by the Institute's Iron and Steel Committee. The following suggestions are also added for the guidance of those who may take part in this research. While' it is not desired to define closely the exact lines or scope of the proposed research, as it is advisable to make these as broad as possible, the object in mind maybe said to be generally as follows: To elaborate and find out the best methods of determining the forms of carbon in steel or iron, including those in iron alloys. A portion of the work would probably be a continuation of the researches which have in the past been carried out by Jullien, Abel, Muller, Ledebur, T. Sterry Hunt, Akerman, Arnold, Stead, E. D. Campbell, Hogg, Parry, Upton, and others. In a generic way, metallurgists now speak of carbides, sub-carbides, double carbides, special carbides, and other combinations. It is very desirable that these should be accurately defined and understood. It is also desirable to know whether there are other or new forms; if so, can these be separated and their characteristics obtained. It may be interesting to point out that the carbon compounds now definitely known are stated to number over 80,000. It is very probable, therefore, that there is room for much valuable and useful research to be carried out with the object of increasing our knowledge of the various combinations of carbon with iron, as probably some of these are still unknown

Jan 5, 1914

Prof. HEnRy Louis, Newcastle-upon-Tyne, Eng. (communication to the Secretary*):—I welcome Mr. Hammond's paper as an attempt to give definiteness to the best modern professional practice. Such a codification of our professiollal ethics is urgently needed, seeing how widely the views of nlining engineers direr on some of the points raised; for example, I have no hesitation in performing a class of work, as to which Mr. Hammond seems to entertain some doubts, and, on the other hand, I strongly condemn a practice which he appears to recommend. I have not the least hesitation in making reports for vendors of mining-properties, and am constantly doing so; the best justification for this practice may be found in the fact that such reports have been repeatedly accepted by buyers as giving a correct representation of the facts of the case, which is all that should be demanded from any report. On the other hand, Mr. Hammond advocates that mining engineers should take payment for their reports in shares of a company to be floated upon the basis of such reports. I hold that this is ethically wrong, as even themost honest of men is liable to be unconsciously biased under these conditions. Indeed, I go much further, and maintain that a mining engineer who reports or advises upon mining-properties should never hold any mining-shares at all, or be himself interested in any mine, and this has been my consistent practice for many years. A man who hold shares in a mine, and is called upon to report upon a neighboring property or a similar mine, can never be wholly unbiased; and even if he could be, he would always lay himself open to the suspicion that he was giving a favorable report 80 as to enhance the value of the property in which he himself is interested, or an unfavorable report so as to stifle competition. It is quite as bad for the manager of a mine or the consulting manager to be interested, because he will have access

Jan 1, 1910

By George Ross Green

[In discussion of the paper of Mr. J. C. Bayles, read at the New York meeting of September, 1890, Trans., xix., p. 18.1 It is often so difficult to locate the causes of failures of machinery and apparatus which can be examined and studied at leisure, that it is not surprising that the causes of explosions should escape detection. Usually the explosion is the first evidence that anything is amiss, and the time for observing the conditions is necessarily brief. An incident in a welding-works near Essen, Germany, might be cited as exemplifying what trifling causes may lead to disaster, and how difficult, under the most favorable conditions, it may be to discover them. A blowing-engine was arranged with two suction-pipes at each end of the blowing-cylinder—one leading to the air, and the other to the gas-holder. Each pipe was provided with a valve, and all were so adjusted that the cylinder drew in gas and air in the proportions found most advantageous. The gases from the cylinder were carried directly to the furnace through suitable pipes, and while the cylinder was provided with relief-valves, every effort was made to prevent explosions, principally by compressing the gases to a point where the rate of efflux of the mixture was greater than the velocity of combustion, if the expression is here allowable. It was found that the apparatus would work satisfactorily for some time, and then the relative proportions of the mixture would change, and an explosion might have been the result. Experiments consuming days were made to discover a method of averting this danger, but they were unsuccessful, until it was observed that the change in the composition of the mixture of gas and air took place when the gasometer began to rise or fall—the back-pressure due to friction when the holder was rising or its absence when falling being sufficient to change the conditions. As soon as this was discovered,

Jan 1, 1892

E. W. King, Bozeman, Mont.: The form of measuring up ore in sight looks very plausible, as illustrated in the paper of Mr. Emmons, but from my experience of many years of mining in Montana and Nevada, I have found it is very hard to measure up anything nearer than a guess of what you have in sight, except in the case of a true vein, or a flat vein where the boundaries are well defined. I have been interested in several miues with Dr. A. R. Ledoux, and I know that my foreman and myself, going into the mines and using our best judgment, could seldom see more than 30 days' supply actually in sight, and yet we were running from 100 to 250 tons a day, and keeping it up year after year. Prof. John D. Irving, New Haven, Conn.: I understand from Mr. Emmons that this is a method which has been found applicable in the copper-mines in Tennessee, where the record could be made with a good deal of accuracy, and where the work in the mines allowed the necessary development to be done, so that the record could be kept up. I do not think there was any intention in his mind to imply that this was applicable to all cases, especially such as Mr. King has mentioned. President Charles Kirchhoff, New York, N. Y. : I think the point is that the paper impresses the necessity for doing it where the possibilities exist. There has been too little attention given to this very matter, particularly in the United States; but I think our English friends are following it very much more zealously, and the demand for it there is possibly greater than it is here, because English boards of directors handle mines that are often very much further away than our own are, and the English public and the English engineers generally are very much more insistent upon seeing how much longer current dividends are going to last, or current assessments are going to continue.

Jan 1, 1913

R. MOLDENKE, Watchung, N. J. (written discussion*).-It is some-what difficult to discuss the paper of Mr. Stork, when the description of the cupola melting occurrences indicates that his practice is open to question. The evident burning of much of the steel charged,. coupled with the remarkably low silicon content of the mixture as shown by the resulting product, throws the entire melting practice into that of making cupola malleable. If anything is wanted here, it is a. high bed to melt upon, and yet Mr. Stork in the very beginning of his paper speaks of the evils of oxidation due to a "high" bed, etc. The experienced foundry-mall would judge at the outset that Mr. Stork has kept his bed in the cupola too low, and naturally got a lot of oxidation from the blast. The oxidation of steel when used in large quantities in cupola mixtures is a well-known phenomenon, and is readily understood. One has but to. put a file into the forge fire and watch it burn when heated high enough. The melting point of steel being higher than cast iron, heavy pieces may dig way into the bed before being completely melted away, the last por-tions being directly exposed to free oxygen from the blast. Another situation not to be forgotten is the oxidizing effect of carbon dioxide at high temperatures. A serious oxidation of the steel is quite conceivable if in the zone of maximum carbon dioxide and minimum carbon monoxide-free oxygen being entirely absent. Hence the well understood practice of never melting a mixture with much steel unless the bed is kept exceed-ingly high; or again the above-mentioned malleable practice. Mr. Stork mentions the impossibility of deoxidizing a heat. after the steel contained has been oxidized. This is true to a great extent with the ordinary deoxidizers, such as silicon and manganese, but can be brought about by vanadium, titanium, magnesium, etc. Proper melting, however, makes this unnecessary.

Jan 10, 1919

By V. F. Marsters

SEEPAGES Of oil in Ecuador have been known for many years. The locality first to receive attention, and still worked in a modest way, lies on the north shore of the Santa Elena peninsula, between La Puntilla and Salinas. Operations were first conducted largely by local capital. Later, foreign companies acquired large blocks of land, where they have done considerable drilling. For details concerning present drilling activities in Ecuador, we are indebted to Leon Price, an American resident engineer of Ecuador. The information solicited, came to the author through the office of the American Consulate,' with permission to use it. The coastal plain bordering the Province of Tumbes, Peru, continues to the northeast, but narrows on passing the Zarumilla River. From this, point northward it widens toward Santa Rosa. In fact, the pampas, as shown on the official Wolf map, correspond fairly well to the areal extent of the coastal plain as far as Guayaquil. This is shown in a general way on the accompanying map. The author understands that the Guayaquil embayment is bordered on all sides by the coastal plain, as recognized at Tumbes and farther southwest, and that it can be followed without a break as far north as Palmar. This view is supported by the mapped area regarded by Mr. Price as favorable or possible oil territory. Moreover the islands in the Gulf of Guayaquil are the same geologically as the coastal edge, being composed of Tertiary sediments. The author understands also that Tertiary formations occur north of Palmar. According to a report by Mr. Cardon, of Guayaquil, Tertiary sediments are exposed in the region of San Francisco and extend to and beyond Pta. Calera. There is also reason to believe that at least the lower part of the valley of the Santiago River is occupied by Tertiary sediments, which probably border the coast line and extend into the River Mira basin, and into Colombia.

Jan 7, 1922

By Wilhelm in der Schmitten

A necessary condition for a uniaxial stress distribution in compression testing is that the specimen end surfaces make full contact with the apparatus compression plates. In addition all compression surfaces must be machined perpendicularly to the loading axis. In general this condition is not sufficiently fulfilled in a simple apparatus. Therefore on application of the load the compression plate may first touch the specimen at one point only. This may cause crumbling of the specimen if the material under investigation is brittle (e.g., ionic crystals). It also precludes a precise study of the beginning of deformation as the effective cross sectional area is unknown. In addition a complex stress state is set up which renders quantitative work impossible, e.g., on dislocation density and arrangement as a function of stress. To overcome these difficulties a "self-adjusting" upper compression plate is required. A simple and reliable method of achieving this is shown in Fig. 1: A steel hemisphere is placed on the specimen. As soon as the compression plate (which no longer needs precise machining) makes contact with this hemisphere the load is uniformly distributed over the whole specimen surface, and a homogeneous uniaxial state of stress results. An advantage of the method is that the loading is always central, even when the specimen surface is not parallel to the compression plate (Fig. 1, dashed line). Therefore to a first approximation a uniaxial state of stress is maintained if the misorientation of the specimen end surface is small. Two typical stress strain curves of identically prepared sodium chloride crystals are shown in Fig. 2; curve 1 was taken without and curve II with the hemisphere under otherwise identical conditions. The improvement in the accuracy of defining the beginning of elastic and plastic deformation is clearly indicated. The writer wishes to thank the Deutsche Forschungsgemeinschaft for financial support, and Professor P. Haasen for providing facilities for this work.

Jan 1, 1962

By G. S. Brooks

DURING the past few years, the Mineral Point Zinc Co. has had under consideration the improvement of various types of gas-filtering apparatus used in the removal of dust from crushing and milling plants, in the manufacture of oxide, and on blast-furnace fume and sintering furnaces. The original equipment of the various plants of the company was, of course, along lines of the standard stationary bag house. These houses required large surfaces, hand shaking, and varied only in the manner of the collection of solids and in the distribution of the gas. Early in 1908, the first trial of a mechanical bag house was made at Nassau Plant at Depue, Ill. The duty of this installation was on dust-laden gas from a fine-crushing mill. The Printz and Rau bag machine was finally adopted and put into operation. This ingenious machine embodied what were then to us two novel features in bag-house practice: 1. An intermittent crinkling and snapping of the filtering fabric to free the meshes of solids. i 2. A reversal of gas flow for a short period by a temporary connection w th the suction trunk. This equipment worked fairly well except in cold weather, when we ran into condensation troubles. Had we at that time understood more fully some of the limitations of fabric filtering work, these might well have been remedied. We were impressed by this experience, however, with the efficiency of sudden tension on the fabric under suction. After a study had been made of some of the Western blast-furnace houses using the reversal-of-flow feature, experiments were started early in 1914 with a view to developing an automatic equipment along the best lines of our past experience. The objects sought were: 1. Keeping labor out of the houses for hygienic reasons. 2. Reduction of labor costs. 3. Reduction in -size of hag houses. 4. Accessibility. 5. Ability to handle relatively hot gases where required.

Jan 11, 1917

J. S. UNGER,* Pittsburg, Pa, . (written discussion?).-The author of the paper has given an excellent description of the appliances used to cool parts of an open-hearth furnace, and some of the reasons why the refractories fail in service. Personally, I favor water-cooling, but to a limited degree. At one time I advocated more universal cooling than is now practised, but believe I must change my mind. Water-cooled, thin-lined blast furnaces have not proved as satisfactory as anticipated. While this may retard the building of many such furnaces, it will not prevent the use of regular tuyere- and bosh-cooling appliances. Water-cooling any furnace may be easily carried to the extreme. In an open-hearth furnace, excessive port or roof cooling, or cooling the working floors may preserve the lines of the furnace, lower the cost of refractories, acid to the comfort of the workmen, and necessitate fewer shutdowns for repairs, but it may not be good economy on account of the high first cost, the cost of cooling water, maintenance of cooling appliances, and the immediate reflection in a higher fuel cost. The question becomes a financial one, and is answered by using water-cooling devices up to the point at which they cease to show true economies. Open-hearth furnace bulkheads, roofs, and ports fail rapidly in about the order named. If they could be made to last indefinitely by water-cooling, the furnace would still have to be shut clown periodically for cleaning the slag pockets, regenerator chambers, and flues. Extra, or spare, pockets and regenerator chambers have been advocated to permit of continuous operation, but the space required, the cost of installation, and the fuel required to initially heat such cold chambers will largely prevent their adoption. Some particular fuels, as high-ash powdered coal, require frequent stoppages for cleaning, but for this particular fuel a special provision can' be made.

Jan 5, 1919

By Wilbur Nelson

Little drilling has been done in Kentucky and Tennessee in 1923, with the exception of the Kettle Creek area on the Kentucky-Tennessee line. Oil prices fluctuated between $2.86 and $1.36 Per bbl. for light oil. The Kentucky production was slightly over 8,000,000 bbl., being 1,000,000 bbl. less than during 1922. Tennessee production was approximately 8500 bbl., being a decrease of 1000 bbl, over. 1922. During 1923, the first producing well was brought in, in Clay County, Tenn. Production in Tennessee will undoubtedly increase considerably in 1924, and Kentucky production will probably increase slightly. THE year 1923 has been a dull period in oil development in Kentucky and Tennessee, with the exception of the Kettle Creek area along the Tennessee-Kentucky line, in Clinton and Cumberland Counties, Kentucky, and Clay County, Tennessee. The price of oil during the year has been so low that wildcatters have shown little interest in drilling. At the beginning of the year, light oil sold for $2.31 per barrel and medium oil for $2.06 per, barrel. Prices increased to the highest point for the year in February, when light oil brought $2.86 per barrel and medium oil, $2.61. In April, prices had declined 35 c. while in May an additional decline of 25 c. went into effect. During June, prices declined 20 c. per barrel; during July, 45 c. per barrel; remained stationary during August and September, and dropped during November and December to the low price of $1.36 per barrel for light and $1.21 for medium oil. At present, an increase of 29 c. has brought the price of light oil up to $1.55, and indications are that the price will continue to increase during the coming months. It can readily be seen that during 1923 the price of oil was such as to prevent any drilling except that necessary to hold leases and to maintain production enough to take care of overhead expenses.

Jan 3, 1924

By H. W. Paxton, G. M. Pound

A method is outlined for taking into account variation in chemical potential of both components in evaluating capillary effects at growing interfaces. The results are compared with experiment, and seem to be in reasonably good accord for Widman-statten ferrite growing in austenite. ENERY pointed out that during the steady-state growth of phases with a rather small radius of curvature at their advancing edge capillarity cannot be neglected. By proper application of the Laplace equation a correction must be made to the activity gradients down which diffusion occurs. Subsequent workers have concerned themselves with attempts to evaluate specific cases by the use and modification of the principles laid down by Zener.2-5 To solve the problem in its simplest form it is necessary to assume thermodynamic equilibrium at the interface and to select some criterion which will allocate the available free energy between reversible and irreversible processes. Zener chose to assume that the division should be made such that the new phase grew at the maximum rate. Other workers have used the same2,3 or different assumptions, e.g., maximum rate of free-energy dissipation,4 minimum rate of entropy production.5 Li6 has proposed that the "thermokinetic potential" should be a minimum at steady state. The purpose of this presentation is to note that most prior treatments have considered variations due to capillarity only in the chemical potential of the mobile constituent, and that a more consistent treatment must involve a consideration of the variation of chemical potentials of both solute -and sol- vent in a binary system.* As an example, the way in which this arises for ferrite growing from austenite may be illustrated by reference to Fig. l(a). The line OABC shows a typical variation of carbon activity with composition at one atmosphere pressure (at a transformation temperature below A3). In the tip of a growing ferrite plate with a hemi-cylindricab leading edge of radius ?, the pressure due to capillarity is*

Jan 1, 1963

By H. Case Willcox

AERIAL photographic surveying and mapping is not new or unknown to geologists. However, it has been utilized but little before, principally because it is only within the last few months that practical means of adapting this method to the requirements of petroleum companies have been discovered. No American aerial survey company has taken up aerial surveying and mapping as an engineering service to be offered to petroleum companies and their geologists for use in undeveloped and jungle-covered petroleum areas. This method of surveying and mapping, however, is used by the War Department, the U. S. Reclamation Service, and Geological Survey, and the corresponding Departments of the Canadian Government. ADVANTAGES OF AERIAL PHOTOGRAPHIC SURVEYING AND MAPPING The advantages of aerial photographic surveying and mapping to petroleum companies and their geologists are many. One of the most valuable is presented in the very first phase, or the exploration period. It is assumed that, when convinced that petroleum possibilities are present, a petroleum company has secured a concession of 8000 sq. mi. of unexplored area in Eastern Venezuela. The company may either have the entire area surveyed and mapped by the aerial photographic method, or send its chief field geologist up in an airplane so that he, from-an aerial reconnaissance, may reject certain portions that, for geological reasons, the company would not be interested in. He will then point out the regions that are to be surveyed and mapped. After the air-work is completed, the results are brought down, developed, and printed; then the resulting "contact prints" are given to the field geologist. They may be roughly assembled to give a general idea of the property in its entirety, or they are in shape to be examined in adjoining pairs under the stereo-scope. With this instrument, the geologist is enabled to make a minute examination of surface indications. The work of assembling and constructing a complete general or detailed map, according to the scales desired by the petroleum company and for the later office use, is continued by the aerial photographic company.

Jan 3, 1925

By John Birkinbine

An item of considerable importance to the producers of pig-iron is the disposition of the slag or cinder from the blast-furnace; and various plans have been adopted at different works to care for the rapid accumulation of this generally waste material. The charge per ton of iron made which must be allowed for the care of cinder is sufficient in times of business depression to give plants having facilities for disposing of their slags an advantage over others less favorably arranged, and to allow iron to be produced profitably in the one case and prevent a profit in the other. The varied methods employed and the means of conveyance utilized need not be detailed. It is sufficient to say that the large outputs of American blast-furnaces, and consequent rapidly augmenting dump-piles, have brought into general favor the use of cars carrying the slag in a liquid condition. The advantages of this method are the prompt removal of the slag, the reduced space occupied by the dump-piles, and the facility of converting the slag into such forms for use as may be desired. The progress in iron-manufactlire is also marked by a more general adoption of methods by which molten metal is carried in vessels away from the point of its production; and, anticipating the prospective advance in pig-iron manufacture, it does not seem unreasonable to prophesy the early abolition of casting-houses at blastfurnaces, particularly where several are grouped together; or the casting of steel ingots away from the converters or furnaces. In some large blast-furnace plants, the iron is carried molten from the blast-furnaces to the converters or other furnaces. Even where it is cast into pigs, casting-sheds removed from the immediate vicinity of the furnace-stack would, perhaps, be superior to casting in beds in front of the furnaces. The idea of casting-sheds appears to present the following advantages : 1st. The equipment of boilers, hot-ovens, and blowing-machinery could be closely grouped around the blast-furnace stacks, permitting

Jan 1, 1887

By Foster Bain

THOUGHTFUL people have raised questions as to how long nature's bank could continue to accept our drafts. These questions came to the fore so persistently, and there were so many evidences -such as the failure of natural gas in Indiana, the increasing scarcity of lumber in the Lake Superior region, the progressive sterility of Southern farm lands, the choking of the Sacramento River by tailing-point-ing to possible danger from overdraft or to misuse of resources and opportunity, that President Roosevelt called a conference which assembled at the White House on May 13, 1908, to consider these and related questions. This, the first great Conservation Congress, had a wide and beneficial influence on the thought of the world. It profoundly influenced the course of succeed-ing events and, while even yet there are sharp dis-agreements as, to the wisdom of much that has been done in the name of conservation, I believe that thoughtful men, and engineers especially, agree that the time had come when sharp attention was properly called to the waste that accompanied development of our resources. RESOURCES LARGE BUT NOT INEXHAUSTIBLE In 1908 there was a surprisingly large number of men, who should have known better, prepared to argue that our resources are "inexhaustible." No competent mining engineer, of course, believes that, as regards minerals at least. They may be, and, in most cases, fortunately are, large; as to many of them our knowledge is too general to permit measuring the reserves; but we know now, and I think the public appreciates, that there is a limit to our supply of gas, oil, coal, iron, and metals. Indeed, with the inten-sive study made necessary to meet the demands of the war, and the more careful accounting required by the newer systems of taxation, depletion has become a common word, and that mines are wasting assets has become a platitude.

Jan 8, 1922

By Horace Williams

IN VIEW of the frequent occurrence of petroleum in other parts of the world, it seems odd that so large an area as is contained within the borders of Brazil should be without this product. This apparent deficiency may be due, however, to our ignorance of the regions in which-it, may exist. In some places, indications point to the probable existence of petroleum in ages gone by; and while the presence of petroleum pools may be problematic, in several regions conditions not unfavorable to their occurrence exist. Yet, Brazil has enormous oil resources in the rich oil-shales in different parts of the country. Many of these shales are very rich and only suitable processes for the extraction of the oil are lacking. At the present time, only a few small experimental plants are producing oil by distillation from these shales. These plants have been the subject of recent investigations by the Geological and Mineralogical Survey, a. pre-liminary report of which is in the hands of the printer. The only regions where studies have not been made are the upper Amazon, the Acre, the Rio Negro, and the Peruvian frontier, which really seems to be the most promising field for, explorations of any in the country. In the vast plateau region of the interior north of the 20th parallel of latitude, granites, gneiss, mica schists, and, very old metamorphosed sedimentaries predominate. Later, sedimentaries occupy a minor position and, where found in the interior, represent a thin veneering resting on the older rocks. At several places near the coast they have a greater development and contain considerable beds of oil-shale and may, in some cases, offer conditions favorable for the occurrence of oil. Such deposits are found in the Permian rocks of central-and southern Maranhão; in the Tertiary and Cretaceous beds along the coast of Alagôas Sergipe, Bahia, and perhaps farther south in Espirito Santo; and in the Parahyba embayment north of Cape Frio and in the interior Tertiary basin of eastern Sao Paulo.

Jan 9, 1920

By H. Scott

IN a paper read before the Institute of Metals, Rosenhain 1 described a new type of furnace designed primarily for the thermal analysis of metals by the inverse-rate method and used by him in the metallurgical department of the National Physical Laboratory with considerable success. In his discussion of this furnace, Rosenhain pointed out some difficulties met with in its operation, such as uniformity of rate of heating or cooling being inadequate for the degree of accuracy aimed at. To overcome this difficulty, he suggested, in place of motor propulsion, a gravity drive controlled by a"hydraulic cylinder with a relief valve whose width of opening can he regulated to allow of any desired rate of motion." The authors, in constructing a thermal-analysis furnace of Rosenhain's type, have therefore followed this suggestion and also added certain features that increase somewhat the convenience and simplicity of its operation. Requests for information regarding this furnace and the highly satisfactory results obtained from its use, it is believed, justify describing its construction and operation in sufficient detail to make possible its duplication or improvement. Description of Furnace.-The details of the furnace construction are shown in Fig. 1, which is drawn to scale. The heating tube is of /4 in. (6.35 mm.) wall "alundum" heated at the upper end by seventeen turns of 0.52 mm. platinum wire, which is coated with "alundum" cement supplied for this purpose. The cement coating is essential when a high temperature (over 1000° C.) is required, as it prevents hot spots with the resulting burning out of the heater. This platinum-wire winding, unlike "nichrome," is entirely satisfactory for temperatures of at least 1000° C. It has been maintained at that temperature continuously for 2 months and shows no signs of deterioration. This temperature is maintained by a current of 5 amp. drawn from 30 volts potential, so its necessarily continuous operation is quite economical.

Jan 8, 1919

By H. F. McCullough

THE success of a coal-mining venture as relates to operations at the gob or break-line, such as the drawing of pillars or the working of long-faces, depends upon the control of face conditions. The measures required to control the latter are dependent upon the action of the coal seam, roof and floor at and in the vicinity of the faces, but the manner in which these will act is dependent upon the rate of face movement as well as upon the face characteristics and upon the forces exerted. Yet the merits of a method of working-the practicability of controlling face conditions and the means required for such control when applied to any particular case-are usually judged only upon a consideration of the characteristics of coal seam, roof and floor, and the manner in which they have been observed to act. Practically every coal-mining man knows that face conditions are influenced by the rate of face movement, but few have appreciated that this is as much of a factor in the control of face conditions as are the face characteristics and the forces exerted. Fewer yet have recognized or taken advantage of faster rates of face movement as one of the principal means of establishing control of face conditions or of securing more favorable face conditions. Seemingly inherent difficulties, particularly in the control of roof conditions, but also in the control of conditions of the coal seam and floor, are frequently mitigated or disappear when the rate of movement of the faces is sufficiently increased. The characteristics of the coal seam, roof and floor and the forces exerted upon them do determine the general trend or tendency of face action, but the manner in which the coal seam, roof and floor will act and be acted upon and the magnitude of the action during the time the site of mining operations remains at any particular point is very largely determined by the rate of movement of the faces.

Jan 10, 1926

By Leo D. Jones

The use of the centrifuge for dewaxing lubricating oils grew out of the effort to secure better results than had been attained by the common "cold settling" process. This process was the only known method for dewaxing steam refined cylinder stock (600" F. fire test), the product known as "bright stock" being commonlyused for building up "pressed," i.e., dewaxed neutrals of, say, 200-sec. viscosity [to a higher value. The process consisted of mixing the cylinder stock with approximately one and one-half times its volume of naphtha, heating, to dissolve completely all the oil and wax and then slowly chilling to about 15" F. in large insulated tanks. This caused the wax to precipitate. It was allowed to settle out by gravity. The supernatant liquid was then drawn off and the naphtha distilled off, leaving a still residue of bright stock. The sediment from the settling, of a slushy nature, was withdrawn. After removing the naphtha by distillation the residue was petrolatum. At some point in the process, preferably after the dilution but before chilling, the mixture was decolored by percolation through fuller's earth. The finished bright stock produced by this process had a cold test of about 50" F. Efforts to improve this by chilling to a lower temperature resulted in a considerable reduction in yield, and increased uncertainty of settling. Even when chilling to 15" F. it was not uncommon to find that after a week's waiting a tank had not settled. It was then necessary to heat and rechill. This uncertainty was a serious problem; in one case a refinery superintendent had men riveters hold pneumatic hammers against the tank for hours, hoping thus to cause agglomeration and settling of the wax. Yields of bright stock above 70 per cent, were uncommon. History of Centrifugal Application It is not surprising, therefore, that many attempts were made to improve upon the results obtained by cold settling. George H. Taber, vice-president of the Gulf Refining Co., Pittsburgh, Pa., made a number

Jan 1, 1924