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By Robert Bell

The regions to which this paper refers include the whole of the Dominion of Canada east of the 130 Rocky Mountains and north of the water-shed of the St. Lawrence. Very little exploration for economic minerals has yet been done in this immense country; but that little has already served to indicate great wealth in some localities. Having been engaged for a number of years in conducting government geological explorations in these vast territories, I shall endeavor to give the members of the Institute an idea of the prospective mineral resources of almost half a continent, as far as they are yet discernible. I purpose confining my observations to the economic minerals, and will not attempt a description of the geology of these territories; hut it will be necessary to say a few words about the rocks in order the better to explain the distribution of such minerals. The Laurentian nucleus of the continent is the principal feature of the geological map of the Dominion. It stretches from Lake Superior to Baffin's Bay, and from Great Bear Lake to the Straits of Belle Isle. Hudson's Bay itself, which is half the size of the Mediterranean Sea of the old world, lies in the center of this area. Its shores are bordered in places with newer rocks. On the west side of James' Bay (its southern prololigation) these extend inland over 200 miles, and consist of fossiliferous Devonian and Silurian strata. On the western and northwestern side of Hudson's Bay proper, altered rocks are met with, some of which resemble the gold-bearing strata of Nora Scotia, some the Huronian of Lake Huron, some the older Huronian, and others the crystalline series of the neighborhood of Sherbrooke in the Province of Quebec. Along the east coast (called the Eastmain)and among the islands lying off it, there is an interesting set of volcanic and sedimentary rocks which appears to be identical with the Animikie and the Nipigon series of Lake Superior. The area which I have characterized in a general way as Laurentian, includes tracts and belts, more or less extensive, of the Huronian series. Such areas appear to be most common, and have been best explored, in the country between the Great Lakes and Hudson's Bay.

Jan 1, 1886

By Franklyn Oatman

IN order that the conditions which obtain in an oil well may be readily understood, a brief description of a typical California well and. a number of the phenomena accompanying same will be given. That the necessity for the exclusion of water be realized, the effects of water intrusion, a description of methods of prevention, and a discussion of causes of failure will be presented, followed by a summary and recommendations. Fig. 1 shows a section of a typical well which illustrates the relation of oil sands to overlying strata. It indicates a deep water sand separated from the oil sand by shale, and the proper place for the final shutting off of water. In this well a comparatively thick stratum of compact shale protected the oil from overlying water so that the operation of landing the water string was a simple matter. In some wells the protecting stratum may be only from 3 to 5 ft. thick and very careful operation is necessary in order to land the water string of casing properly and not puncture through to the oil sand. The cases just cited are common, but occasionally, after excluding overlying water, productive oil sands are drilled through in the expectation of finding more productive underlying sand, and a water-bearing stratum is tapped. In this case the problem is the reverse of the normal; water must be prevented from ascending rather than descending. A discussion of well-drilling methods is not within the scope of this paper, except such operations as pertain to shutting off of water. A brief outline of the several conditions which may accompany drilling follows. Some or all may be present in any particular case. The direct relation of these to prevention of intrusion will he discussed in detail further on. In drilling, the hole. becomes more or less irregular in shape, and rough, and as the casing follows the bit into the well it does not fit snugly against the walls. As a result, water may descend between the casing and walls of the well. If a circulation pump is not used during drilling, the hole is simply punched through and the pulverized material removed from the well by means of a bailer. If circulation is maintained there is a continual flow of water down inside the casing and up around the outside between the pipe and the walls of hole. This keeps an open. space around the pipe.

Jan 3, 1914

By H. M. Bannerman, E. N. Cameron

INTRODUCTION DURING the years 1942-1944, about 125 New England deposits were mined for sheet and punch mica, and many others were briefly prospected. During this period the Geological Survey, United States Department of the Interior, carried on detailed studies of the deposits and the pegmatite bodies that contain them. The primary purpose of the studies was to provide geological information that would contribute toward efficient mine development and operation. The studies were aimed directly at practical production problems. Detailed maps showing the structure of the deposits were prepared, and geological findings were closely correlated with data on specific yields and costs of mining and processing. The result is information that permits a reasonably accurate appraisal of the mica deposits of New England and the mining industry that they support. At a time when the future of the industry is in doubt, it seems desirable to submit this appraisal for consideration. Domestic mica deposits supply only a small fraction of the country's needs in normal times, for only the richest domestic deposits can compete with the low-cost mines of India and Brazil. However, the possibility that this country may be cut off from its supplies in time of war gives domestic deposits an importance much greater than their peacetime production would imply. New England supplied about 22 per cent of domestic output in 1943 and 1944, the peak years of wartime production. Its actual contribution to the war effort was greater, for the proportion of sheet mica of high quality in the New England product is higher than the average for domestic mica. The data analyzed below were collected for the Geological Survey by D. M. Larrabee, A. H. McNair, J. J. Page, V. E. Shainin, G. W. Stewart, and the co-authors of this paper. The cooperation of officials of Colonial Mica Corporation and of mine operators and owners in furnishing information is gratefully acknowledged. D. M. Larrabee, A. H. McNair, and V. E. Shainin have made various suggestions based on critical reading of the manuscript. ANALYSIS OF WARTIME OPERATIONS In considering the data presented in this report, it must be remembered that the scale of mica operations is very small compared with that of many other mining industries. The typical New England mica mine of 1943 and 1944 was worked by a crew of five or six men. Equipment was varied but on the whole extremely simple. The first stage of operation at a deposit was normally opencut mining. Drilling was done mostly with jackhammers powered by portable compressors driven by gasoline engines. Muck was shoveled by hand into buckets with a capacity of 1/3 to 2/3 ton and commonly hoisted by derrick to a dump adjacent to the cut. As operations were carried to greater depth, and the transition to underground mining was made, these methods were modified to a degree depending largely on the attitude of the deposit mined. At steeply dipping deposits,

Jan 1, 1946

Jan 1, 1880

By G. V. Raymor, James T. Waber, I. Rex Harris

The lattice parameters of a series of fcc alloys of cerium and thorium were measured at 93 " and 298OK. Lattice parameters were also estimated for 171OK. Substantial deviations, y, from Vegard's law were observed. Although y was negative at the two higher temperatures, it was positive and large at the lowest temperature. A variety of models, which have been proposed in the past, were considered, and the calculated values of y were compared with the observed values. The best agreement was achieved with values computed with Friedel's equation. THE purpose of this investigation was to determine the effect of temperature on the lattice parameter and on deviations from Vegard's law of Ce-Th alloys. A large negative deviation from Vegard's law was first observed independently by Weiner, Freeth, and Raynor' and Van vucht2 in the room-temperature lattice parameters of Ce-Th alloys that form a continuous series of solid solutions. This observation was confirmed by Evans and Raynor. The allotropy of unalloyed cerium was reviewed recently by Gschneidner, Elliott, and McDonald. In two subsequent papers,5" these authors reported the influence of various alloying additions on the y= transformation, which occurs below room temperature. Although other rare earths tend to stabilize the double-hexagonal phase, thorium, plutonium, and scandium as solutes tend to stabilize the normal fcc phase. With addition of sufficient thorium as a solute, there is evidence that the formation of is suppressed and it becomes possible to pass continuously with decreasing temperature from the room-temperature phase to the fcc a phase. Thus there is a closed loop which is similar in many ways to the y loop well-known in ferrous alloys. A closed field also occurs in the pressure-temperature "equilibrium" diagram of unalloyed cerium. Because of interest in the effect of thorium additions and their influence on the a and phases, lattice-parameter measurements were made at low temperatures on the fcc phase for a series of alloys ranging from 10 to 90 at. pct Th. The results obtained at three temperatures are shown in Fig. 1. Evans and Raynors analyzed the deviations from Vegard's law in Ce-Th alloys in terms of changes in the occupancy of the 4f electron level in cerium,

Jan 1, 1964

By Henry P. Ehrlinger, James C. Bradbury

Tripoli is a naturally occurring, very finely divided form of silica found chiefly in some midwestern and southeastern states and used commercially as fillers and abrasives. Definitions Tripoli is a microcrystalline, finely particulate, more or less friable form of silica that appears to be the product of leaching of siliceous limestone or calcareous chert. The term was originally applied to a deposit near Seneca, MO, that resembled material of that name found near Tripoli In North Africa (Hovey, 1894). The two deposits were subsequently found to have different physical characteristics -the North African tripoli, now called tripolite, is a diatomite, composed of the siliceous skeletons of microscopic marine plants called diatoms; the Missouri tripoli contains no diatom remains. The term tripoli, however, continued to be used for the Missouri material and is now applied in a general way to most silica deposits similar to it in characteristics and geologic origin. In commercial trade tripoli is commonly understood to designate material from the Missouri-Oklahoma field; silica from southern Illinois, the other major producing area, is referred to commercially as amorphous silica. Each term, however, may be used commercially for material, regardless of place of origin, that has the characteristics or uses commonly ascribed to the material from one or the other major producing area. For example, in the commodity price listings, Engineering & Mining Journal routinely lists under Tripoli, prices "f.o.b. Elco, IL" and "f.o.b. Seneca, MO, and Rogers, AR," and under Silica, amorphous, prices "f.o.b. IL," and "f.o.b. bierks, AR." Amorphous silica, the commercial designation given to southern Illinois tripoli, is, like the term tripoli, a misnomer. Mineralogically, the southern Illinois deposits are composed of microcrystalline quartz, and no amorphous material has been detected during X-ray and scanning electron microscope investigations (Leamnson, Thomas, and Ehrlinger, 1969; Thomas et al., 1970; Keller, 1978). Soft silica is another term that has been applied to Illinois and Tennessee tripoli, presumably to distinguish it from the more compact Missouri material. It has also been used in the ceramic trade to distinguish tripoli from "hard" silica, or silica flour, produced by pulverizing silica sand (Heinz, 1937). Rottenstone, produced commercially in Pennsylvania, is similar to tripoli in that a major constituent is finely particulate silica, and its uses are much the same as those of Tripoli-as abrasives and fillers. The origin of rottenstone also is similar to that of tripoli-decomposition of a siliceous sedimentary rock. The parent rock is defined as a siliceous limestone (Gary, McAfee,, and Wolf, 1972; Thrush, 1968) or as shale. Heinz (1937) quotes a brief statement describing the Pennsylvania deposits -"a black impure shaly limestone grading into black shale"-but does not identify the source of the statement. For convenience, rottenstone is included with tripoli in the reporting of production statistics in US Bureau of Mines (USBM) Minerals Yearbooks. Other materials that have been called tripoli include siliceous deposits in San Bernardino County, California (USBM Minerals Yearbooks, 1934-1941) and in Nevada (Chandler, 1960). These, however, differ in composition and/or origin from tripoli and, therefore, should not be identified by the name tripoli.

Jan 1, 1983

By Charles Catlett

The terms " developed " and " undeveloped " are necessarily relative and cover a wide range; but the latter is here applied to cases in which the information at hand falls short of a clear demonstration of values, and conclusions must be reached frorn a study of the geological conditions of the particular deposit, interpreted in the light of similar and closely-related deposits. Such an inquiry might be characterized as an effort to reach reliable conclusions from insufficient data. But the engineer

Jan 1, 1909

By Clarence P. Linville

A previous article1 by the authors contained a general description of the new roasting furnace herein described but it did not go into detail as to the metallurgical behavior or the results obtained. Believing that such information would be of great value, they have elaborated on the subject and have given many unpublished details. The furnace described applies the principle of roasting finely divided zinc-sulfide ores, now produced in large quantity by the flotation process, in gaseous suspension; that is, the ore particles are carried, in suspension, in a current of air and gaseous products of the roast. The relatively great fineness of flotation concentrate presents difficulties and problems of roasting in furnaces of the ordinary type; the fine ore is forwarded through the furnace in the form of a shallow bed and its very fineness leads to dense impervious bedding which prevents oxygen from reaching the interior of the bed, thus unduly lengthening the time of roasting and preventing the elimination of the last of the sulfur. The fineness of the concentrate, normally, should lead to a rapid and complete roast, for the speed of roasting is a function of the surface exposed to oxygen, which surface is greatest, per unit of weight, in very fine material. The difficulty in bed roasting is to get the oxygen to the particle. If the fine ore, during the roasting, could be freely suspended in oxidizing gases, full advantage could be taken of the great surface conferred by its fineness. This fundamental idea, of course, is not new, for the Stedtefelt furnace, familiar to the older metallurgists, is an example of it; but the manner in which this is accomplished may be new. The numerous efforts to roast in gaseous suspension show that the idea is attractive; in fact, an analysis would indicate that it is the most reason-

Jan 1, 1925

By M. J. Sheriff, D. H. Smith, W. Macdonald

The paper outlines the basic procedure used in electrical system planning and design. Consideration is given to the use of applicable codes and standards, development and use of a system One Line Diagram, power availability, load requirements and power factor. Also discussed are the factors influencing the selection of power supply and distribution arrangement, voltage levels, system grounding, distribution and utilization equipment such as switchgear, transformers, motor control, cable systems, motors. Short circuit calculation methods and system protection are discussed.

Jan 1, 1978

By E. S. Bartlett, D. N. Williams

QUANTITATIVE values for the oxidation rate of unalloyed molybdenum in air at temperatures above the melting point (1460°F) of the characteristic oxide are contained in the literature as a result of previous investigations. Lustman' reported values corresponding to 0.36 in. penetration per day (IPD) at 1500 and 1600°F in still air, noting essentially no variation in rate with temperature. Jones, Spretnak, and Speiser' reported values corresponding to 0.14 and 0.13 IPD at 1500 and 1800°F, respectively, in still air, attributing the decreased oxidation rate at higher temperatures to a lesser accumulation of the corrosive molten oxide on the surface at the higher temperature as a result of increased volatilization rate. Harwood3 ecently summarized work in the field, presenting generalized data corresponding to 0.48 to 0.96 IPD at 1800°F and 0.55 to 0.83 IPD at 1700°F in slowly flowing air. In a recent program at Battelle, it became desirable to know more about the characteristic oxidation behavior of molybdenum under varying conditions of temperature and atmosphere. Using oxidation-test apparatus designed for dynamic, continuous recording of weight change during testing,' values for the oxidation rate of molybdenum were obtained at temperatures from 1400 to 2150°F. In addition the effect of air flow on the oxidation rate was studied briefly at temperatures of 1600, 1800, and 2000°F. Exhaust of the contaminated atmosphere from the oxidation chamber was effected by an impeller pump attached to a 3/16-in.-diam opening in the oxidation chamber. The volumetric exhaust rate (cubic feet per hour) was normally maintained slightly in excess of the input rate to avoid condensation of MOO,,' on the sample suspension rod. The entering atmosphere was preheated prior to admission to the oxidation chamber by a 1 1/2-in.-diam cup packed with shredded asbestos. The experimental data are presented in Table I. Comparing conditions 2 and 3 (taking into account the temperature difference) and conditions 8 and 9. shows that in the absence of forced exhaust an atmosphere of moving air results in greater oxidation rate than a stagnant atmosphere. The use of forced exhaust, as shown by comparing conditions 3 and 4 and conditions 14 and 15: resulted in an even greater increase in oxidation rate. By virtue of the size of the atmosphere input and exhaust openings, it was calculated that the exhaust velocity was about 60 times that of the input velocity for essentially equal volumetric flow rates. Because of the proximity (about 3/4 in.) of the exhaust port to the specimen, it is logical to assume that cleansing of the atmosphere immediately surrounding the specimen was accomplished much more efficiently by the exhaust flow than by the input flow at a constant-volumetric flow rate. Also, it can be seen by comparing conditions 4 through 7 and conditions 11 through 13 that increasing the rate of atmosphere flow (by increasing input velocity with a proportional increase in exhaust velocity) above some optimum value has little, if any, further effect on the oxidation rate. These results suggest that there is a maximum oxidation rate for molydenum at a given temperature which is obtained when conditions are maintained such that the partial pressure of MOO3 in the atmosphere surrounding the specimen is at a low value. By controlling the partial pressure of MOO, surrounding the sample, it is possible to control the rate of volatilization of MOO:, from the surface. This, in turn, affects the rate of oxidation, since the thickness of the MOO3 layer determines the amount of oxygen which will be able to reach the reaction surface.' When the liquid oxide layer is less than some critical thickness, i.e., when the volatilization rate is high, enough oxygen is transported to the active surface to permit oxidation to proceed at the maximum rate allowed by the kinetics of the oxidation reaction. However, if the volatilization of MOO,, is suppressed, the thickness of the layer of MOO3 on the surface increases, and the diffusion of oxygen through the oxide layer becomes the rate-controlling step in the oxidation process. The lack of agreement between the present results and those of previous investigators is presumed to be due to differences in removal of the oxidation product (Moo,) from the immediate vicinity of the sample. By comparing conditions 1, 5, 10, 12 and 14, it is seen that when forced exhaust was used the oxidation rate of molybdenum increased with increasing temperature. A rapid increase was observed between 1400 and 1600°F, attributable to the effects

Jan 1, 1959

By Eli T. Conner

(Wilkes-Barre Meeting, June, 1911.) My connection, under a commission from the Councils and Board of School Control of the city of Scranton, Pa., with a recent investigation of mine-caves and the resultant damages to surface-improvements, has led to the preparation, at the invitation of our Secretary, of the present paper. It is notorious that there are, in the anthracite-fields, frequent subsidences of the surface, due to the removal of the coal beneath. No particular attention is paid to such occurrences, unless they happen to injure surface-improvements. Many caves have happened in Scranton and its vicinity, which have excited but little remark, since they have generally caused no serious damage. In August, 1909, a cave occurred in the Hyde Park section of the city, generally known as the West Side, which nearly destroyed school-house No. 16 and considerable adjacent property. 'Fortunately, there were no pupils in the building at the time; but the thought of the possible result, bad the usual number of pupils and teachers been present, aroused the public to the gravity of the situation; and the School Board employed engineers to investigate the case. Two reports were made by separate sets of engineers, which differed in some particulars. These differences were pointed out in the public press and magnified, and the consequent agitation of the subject was taken tip and greatly exaggerated by some of the metropolitan newspapers, giving to uninformed people the very erroneous impression that the whole city of Scranton was in danger of sinking into the bowels of the earth. All this tended to affect the credit of the city and to depress real-estate values. The matter was considered at a joint meeting of the Board of Trade, the Councils, and the School Board. The Hon. J. Ben. Dimmick, a former Mayor, suggested that it

Sep 1, 1911

By William Colby

INCREASING governmental control of human activities seems inevitable. Within the present generation railroad rates and the public sale of water, gas and electricity have been subjected to rigid regulation. The field of control is slowly but surely being enlarged, and it is the object of this paper to outline in brief space this tendency toward increased governmental regulation, as far as mineral resources are concerned. Our, dual form of government complicates the problem. We must deal not only with the powers of the Federal Government, but also with those of the individual States. In order to approach this question intelligently we must have some conception of the powers and jurisdiction of the States and the United States, respectively, over mineral lands and mineral production. Starting with the Federal Government we find it never owned any public domain within the States that formed a part of the thirteen original colonies and, for historical reasons, the same is true of Tennessee and Texas. The Mid-Western States were erected out of the public domain which was acquired by the United States through cession from the original States or by purchase from foreign nations. Congress early in the last century adopted a policy of leasing public lands containing lead deposits in a portion of this Mid-Western territory, but later abandoned that policy and disposed of such public, lands, mineral and non-mineral, outright so that they long since have practically all passed into private ownership and become subject to the general jurisdiction of the respective State governments. In the great public domain lying west of the Mississippi River, and in portions of some of the Southern States, the Federal Government adopted a new mineral land policy following the discovery of gold in California. (Acts of Congress of 1866, 1870, and 1872.) The mineral lands within these States, instead of being disposed of on the game basis as agricultural lands, as occurred in the Mid-Western States, were segregated from agricultural lands and sold under special laws intended to encourage mining, giving the miner the free right to locate and work these mineral lands without paying any royalty to the Federal Government. A miner could also obtain at slight expense a complete

Jan 1, 1930

TO THE BOARD OF DIRECTORS AND MEMBERS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS. GENTLEMEN: Submitted herewith are the report of the Treasurer for the year 1941 and re¬ports for the same year of the following standing committees: Admissions, Mem¬bership, Papers and Publications, Mining and Metallurgy (Magazine), Library, and Student Relations. These reports present additional details. Membership For the fourth year in succession, mem¬bership reached a new all-time high, level as shown in Table 1. The total at the

Jan 1, 1942

By W. A. Alexander, L. M. Pidgeon

Metallic magnesium and similar meta!s near the top of the electromotive series have been commercially produced by the electrolysis of a suitable molten salt. Despite the success of electrolysis, sufficient inherent objections exist to justify the search for a direct reduction method. Such a method would widen the choice of raw materials, relax the rigid electrolytic requirements of raw-material purity, and, by obviating direct current, over simplicity of plant equipment. This paper describes the pilot-plant development of one such method, which has subsequently formed the basis of operation of six commercial plants-—one in Canada and five in the United States. Unlike aluminum, magnesium is volatile at relatively low temperatures. This physical property, which produces its greater inflammability, also offers possibilities of direct reduction that are not available with aluminum. In the basic reaction MgO + X = XO + Mg if X is nonvolatile, the reaction may be forced to the right at high temperatures by the evolution of magnesium vapor, despite the large negative value of the heat of reaction which is almost bound to follow the use of any available commercial reducing agent. The cheapest X, of course, is carbon, but this notable advantage is modified by the production of a volatile oxide CO, so that both Mg and CO are evolved simultaneously. Elaborate devices are required to shock-cool the equilibrium mixture in order to prevent back reaction. At best, a pyrophoric powder is produced, requiring redistillation to provide marketable metal. The practical development of this process, is due to F. Hansgirg, and his methods have recently been given a trial on a grand scale in the plant at Permanente, California, and smaller plants were previously built in Austria, England and Japan. A second class of reducing agents is available, those which produce nonvolatile oxides. When XO and X are relatively nonvolatile, magnesium is the only volatile member of the system. It may be evolved in a simple distillation step and condensed without the formation of powder. Two basic requirements must bc fulfilled in order that such a reaction may proceed: I. The reducing agent when heated to a reasonable temperature in presence of MgO must cause the production of an appreciable equilibrium vapor pressure of magnesium. This magnesium must be removed continuously. z. A supply of heat must be maintained. In order to fulfill the first requirement, operations must be conducted in vacuo or in a stream of Hz. Owing to its greater efficacy and relative safety, vacuum has been employed in the work to be described. The choice of a suitable reducing agent formed the subject of an extensive series

Jan 1, 1944

By J. D. A. Morrow

This discussion relates to the distribution of coal under the di , of the U. S. Fuel Administration beginning Apr. 1, 1918. At t' L a definite method of controlling and directing distribution was put int effect. Prior thereto, although some of the machinery utilized was in operation, especially in the few weeks immediately preceding' Apr. 1, distribution had not been effectively and comprehensively organized. The writer was called to the Fuel Administration by Dr. Garfield about the first of February, 1918, to assume general direction of the distribution of coal for the Fuel Administration, to develop the general plans, and to obtain practical men to assist in this work and in carrying through the program finally devised. A study of the situation and conferences with the Fuel Administrator and leading men in the business made it plain that it would be necessary to begin at the bottom, measure the undertaking, develop plans to meet the need thus shown, and build an organization to effect the distribution required. This work had to be done under war pressure in the midst of a bad coal shortage. The successful performance of such a task is always primarily a matter of putting competent men in the right places and giving them the power and opportunity to function properly together. In the Distribution Division of the U. S. Fuel Administration, the men who were chiefly responsible for whipping plans into practical form and then for carrying out these plans were A. W. Calloway, of Baltimore, President of the Davis Coal & Coke Co., who served as the Director of Bituminous Coal Distribution; S. Lovell Yerkes, of Birmingham, Alabama, Secretary of the Grider Coal Sales Agency, who assumed general charge of distribution while the new plans and organization were being perfected and then became the Assistant Director of Bituminous Coal Distribution; Warren S. Blauvelt, of Detroit, who was Director of Coke Distri. bution; A. S. Learoyd of New York, Director of Anthracite Distribution, in connection with the Anthracite Committee, consisting of Joseph P. Dickson, President of Dickson & Eddy, Chairman; S. D. Warriner, President of the Lehigh Coal & Navigation Co., and W. H. Richards,

Jan 1, 1920

By H. F. Moore

We have studied the simple case of repeated stress, without considering impact, which might bring in other factors. This investigation has shown that steel under repeated applications of stress, reversed from positive to negative, will not fail below some fairly clearly defined limiting stress that, so far we can see, does not bear any definite relation to the ordinary elastic limit, being as large as the elastic limit in some cases and about one-half the elastic limit in others. According to one theory, fatigue is the result of changes in crystalline structure by repeated stress. I do not know of any evidence in favor of this theory. The crystals are broken under repeated stress. According to Bauschinger, under repeated stress some inherent property of the material changes its elastic limit; possibly some property of the amorphous cement between the crystals. A third theory is that all fatigue of metals is the result of the spread of damage from little localized overstresses. While I do not feel justified in accepting the last theory rather than the second, I have yet to run across a case of failure of steel or other metal, either in the laboratory or in service, that could not be explained by the gradual spread of damage from some nucleus. We have found, for example, that it is possible to subject a homogeneous steel, like Armco iron or a 0.90 per cent. carbon steel, that has been thoroughly annealed, to one hundred million reversals of stress as high as the elastic limit of the steel with no sign of failure. On the other hand, a complex structured steel, like a chrome-nickel steel that has been hardened with very little drawing, will fail at a stress about 58 per cent. of its elastic limit. Between these two we get a variety of results. In the steel work of any building, there are undoubtedly many thousands of places where structural damage was done—where riveted members were bent into place cold and where the rivets were fitted with drift pins, etc. Locally the steel in the building was stressed beyond its yield point in many places. These little localized overstresses do no damage at all; the building is entirely safe. But if this building were subjected eight or ten times a day to a mild earthquake, these little localized overstresses might be nuclei from which damage would spread

Jan 1, 1922

THERE are many kinds and varieties of earth* that are used for the loam compositions for making the moulds for casting bronze, brass, or other metals. Since this is a very necessary thing, you must try to have the best kind and one that resists the fire well. It must be disposed to receive the metals well, must make a neat casting, and must not shrink or break with cracks on drying or baking. Aside from actual trial, I believe that there is little that can help you, since the clay in itself has no color or [77] visible sign that I know of to show how satisfactory it is. Understand that their colors are no less varied than their natures, for, as you see, one is white, one black, one yellow, and another red. Perhaps none will show by its color that it is good for this work, yet it might also happen that all colors are good. But all that I can say about it is to show you by their effects how the good ones should be in their nature; and so by trial you will choose among those that come into your hands. All earths are either sandy or tufaceous, either argillaceous and lean or pasty with unctuous viscosity. The lean ones make the loam powdery and without toughness and hold together poorly by themselves when they are dry. The unctuous and viscous ones shrink and break. Becoming smaller by shrinking, they often twist the forms and they stick together badly. They swell up again in the fire and produce works that are neither exact-a nor neat. Therefore, the good ones must be those that are neither unctuous nor lean, neither wholly tender nor rough, and with a grain that is fine, without pebbles or shells. When applied to a work they easily dry out without fractures and, when dry, hold their own shape well. Above all they must resist the fire well. These are usually of a yellow or red color, but whatever their color may be, the color does not force me to say that the yellow are really better than the black, and the red than the white or gray. Their quality depends on what trial shows. Thus, to summarize, whenever you have to do this work, you must try to have the best clay that you can, because it is to be the foundation of

Jan 1, 1942

By Edwin Ludlow

THERE has been so much misinformation sent out through the newspapers, and I find so few people who are really acquainted with the true facts in regard to the coal strike, that I feel it would be advan-tageous to present the facts as I have been able to gather them. One of the great points that the miners are now mak-ing is the fact that the operators of the central competi-tive field, consisting of the states of Illinois, Indiana, Ohio and Pennsylvania, have refused to meet them in a joint conference such as has been customary in previous years. There are two reasons why the operators de-clined to hold such a meeting. In the first place, the last time they held a meeting of this kind they were all indicted under the Sherman Act for making an agree-ment in restraint of trade. In the second place, the miners at their convention did not authorize their dele-gates to negotiate a new contract, but instructed them that nothing less than a scale based on the present wage, with the addition that there should be a six-hour day, a five-clay week, time j and a half for over time, and double time for Sundays, would be accepted. These additions would very much increase the cost of coal over the present wage scale. The operators could not consider renewing a contract on the present scale, as it would mean ruin for them, and as the miners were not authorized to negotiate a new scale on a fair basis that would enable the operators to mine coal in competi¬tion, with the open-shop mines the operators did not feel that there was any use in meeting the delegates. Thirty per cent. of the output of bituminous coal comes from the open-shop mines of West Virginia, Alabama and Pennsylvania. During the strike, in 1919, this 30 per cent. was increased to 50 per cent. and it has affected the operations of the union mines to such an extent this year that they have been able to run only 15 to 30 per cent. of their time, while the open shop mines have run from 60 to 80 per cent. as the wages in these mines had been reduced to the 1917 scale.

Jan 5, 1922

By H. H. Hausner, H. S. Kalish

IN recent years zirconium and beryllium have become of great interest because of their special properties. Zirconium is known for its remarkable ability to absorb the gases oxygen, nitrogen and hydrogen, has extensive use as a getter in electron tubes and has indeed become the primary metal in the manufacture of photoflash bulbs. Beryllium is of interest because it is light metal and as such could supplement aluminum and magnesium in light metal applications. The late development of zirconium ductile at room temperature produced by both the iodide and calcium reduction methods has stimulated frequent articles on this metal in the recent literature. Beryllium is so closely akin to zirconium crystall-ographically that some investigators are of the opinion that beryllium should be ductile at room temperature if it were pure enough. The crystallographic relationship of beryllium and zirconium, the interest created in Be-Zr alloys where the zirconium is believed to function as a remover of solid solution gas in beryllium and thus increase the ductility of the beryllium rich alloy, and the amenability of these metals to powder metallurgy methods stimulated this approach to an investigation of the system Be-Zr. Preliminary work showed that a zirconium compact melted when pressed in contact with a beryllium compact and sintered at 1250°C, without any apparent final bond between the two. A search of the literature revealed nothing pertinent about the Zr-Be system or about any zirconium - beryllium alloys. In 1936 Misch³ vaguely identified the compound ZrBe2 and reported that it has a deformed cubic structure. Two patents," , were issued to Mach-lett Laboratories in 1943 and in 1946 regarding the addition of small amounts of zirconium to beryllium in order to improve the ductility of beryllium so that it may better be used for X ray windows. In considering the alloy formation of beryllium with other metals Raynor thought it unlikely that zirconium would have any solid solubility in beryllium. From this indefinite information nothing could be ascertained about the possible use of Zr-Be alloys or the use of these metals intimately. A brief preliminary study of the system Zr-Be by powder metallurgy methods was undertaken to provide regions for more intense studies of Zr-Be alloys and as a guide to a formal phase diagram determination. The investigation described in the following pages was completed in less than three weeks. The usefulness of this rapid method to facilitate phase diagram studies and new alloy investigations will be shown. Materials and Procedure Zirconium powder was produced from crystal bar stock of high purity supplied by Foote Mineral Co. The crystal bar was converted to hydride at 730°C, crushed, and the hydride decomposed in purified argon at 850°C. 60 pct of the powder passed through a 325 mesh screen, 40 pct of the powder was —140 mesh, +325 mesh and the average particle size of the total was 8 to 12 microns. The beryllium powder was used as re-

Jan 1, 1951

By R. M. Lumley, J. D. Wood

In this investigation, polyethylene terephthalate (Mylar) was coated with various thicknesses of a vapor-deposited silvel- precoat followed by a uapor-deposited zinc using several orders of- magnitude variation in deposition rate of both the silver and zinc. The grain size and resistivity of the zinc film was primarily a function of the silver precoat thickness (in the range of 0.001 to 10 average Agprecoat thickness) and a secondary function of the zinc film thick-ness. The silver and zinc deposition rates were found to have a minor effect on the characteristics of- the zinc film. Electron and X-ray dilffraction results slwwed that all zinc films exhibited a fiber texture mith the (0001) axes essentially perpendiculav to the platze of the film When coating nonmetallic substrates such as paper or plastics with zinc metal vapors, it is found that the zinc will not condense unless extremely high evaporation rates or very low substrate temperatures are used. In 1931, Fraser' reported a procedure whereby zinc could be made to condense on nonmetallic substrates by depositing a very thin precoat of silver. Utilizing Fraser's method, the ermans' developed a commercial process of making "metallized film" capacitors during World War 11. The metallizing process, which was introduced in the United States shortly after the conclusion of World War 11, became one of the first large-scale commercial applications of vapor-deposited metal films and remains one of the larger applications in the electronics industry. The process, as developed by the Germans, consisted of depositing a thin precoat of silver on lacquered, kraft paper followed by a conducting layer of zinc. The resulting silver-zinc film was used as the capacitor The term silver-zinc will be used throughout thiz paper to mean a metal film formed by an extremely thi layer of silver, 10A or less in average thickness, and a zinc film IOOA or more in thickness deposited on the silver film. ---. electrode with the lacquered paper being the dielectric. When polyethylene terephthalate was marketed by E. I. Du Pont Co. in the early 1950's under the trade name Mylar it was substituted for the kraft paper in many capacitor applications. Even though manufacture of metallized paper and metallized Mylar capacitors has been a large commercial process for many years, little information has been published about the deposition parameters. Correlating the work of others to the various effects to be expected of deposition parameters on silver-zinc films deposited on Mylar, it is expected that the

Jan 1, 1967