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By M. I. Jacobson, M. L. Hammond

The solid solubilities of high-purity silver, aluminum, chromium, copper, and iron in zone-refined beryllium have been determined. Diffusion couple sandwiches of beryllium with aluminum, copper, and silver foil and diffusion couples of beryllium with two-phase alloys in the Be-Cr. Be-Fe, and Be-Ag systems were analyzed by electron beam micro-probe techniques. This paper describes the material used, the experimental methods for preparing the diffusion couples and the alloys, the analytical techniques, and the results obtained. The results are compared with those of previous investigators who used materials of lower purity. ~NVESTIGATORS of beryllium phase diagrams have often been hampered in their interpretations of certain phase boundaries because of the relatively low purity of the beryllium used. This has sometimes resulted in the appearance of three phases in the regions where only two should exist. Advances in purification methods, specifically zone refining, have made available beryllium that is considerably purer than the material previously used for phase diagram studies. The primary object of this investigation was to reex-amine portions of the beryllium-rich end of the binary systems of beryllium with silver, aluminum, chromium, copper, and iron to determine more accurately the limits of terminal solid solubility. The five elements—silver, aluminum, chromium, copper, and iron—include some which are commonly found as the major impurities in beryllium, some of which are being used as solid-solution alloying elements, and some of which are used in ductile matrix alloys. They are thus of considerable importance to physical metallurgists who must work with beryllium but who must rely on the present inaccurate or incomplete diagrams. The determination of more reliable diagrams would aid researchers concerned with the problems of alloying, heat treatment, and ductility. MATERIAL The beryllium was acquired from the Franklin Institute in the form of a single-crystal, 6 in. long by 1 in. in diam, zone-refined in three passes from Pechiney SR-grade beryllium bar. The principal impurities, as determined by mass spectrography at Battelle Memorial Institute, are shown in Table I. Vacuum-melted copper, silver, and aluminum, and electron-beam zone-refined iron were obtained from the Materials Research Corp. in the form of 1/2-in.- diam bars. Iodide chromium was obtained as flakes from the Chromalloy Corp. Analyses supplied with these metals are shown in Table 11. EXPERIMENTAL PROCEDURE Preparation of Diffusion Couples. Two types of dif-fusion couples were used in this study. For the copper, silver, and aluminum systems, the couples were sand-

Jan 1, 1969

By G. D. Tranter

THE importance of ladle and teeming practice and its relationship to the yield and quality of the product has focused considerable attention on this phase of open-hearth operation. Inherently bad steel cannot be perfected by manipulation during teeming, but through the proper handling of "off heats" serious losses, which in many cases arise, can be greatly minimized. Conversely, good steel can be ruined as a result of poor workmanship in the pit, and rendered unsuitable for application to orders where exacting surface and physical requirements are essential. Sufficient evidence has been secured to warrant careful investigation of pit operations when an abnormal number of basic defects develop in the semifinished product or are found on the inspection table. This paper is written from the standpoint of the problems involved in making satisfactory ingots for sheet rolling. Furthermore, since rimming steel is almost universally used for manufacture of sheet, the data presented herein refer particularly to that type of steel. Going back some 30 years in open-hearth history, the word "pit" properly described the hole into which the ladle was lowered to receive the metal tapped from the furnace. The working space was necessarily limited, and the disposal of slag and metal overflowing the ladle or lost because of breakouts presented a serious problem. The equipment, of course, was rather crude in the light of present-day development. Often no ladle stands were provided, the ladle being hung on the crane beneath the runner. When delayed taps occurred, the ladle was often held in position for many hours, thus tying tip pit operations and causing delays to adjacent furnaces. Because of crowded conditions, slag thimbles were not used and a network of cast-steel triangles and old tapping bars, placed before the heat was tapped, was the means for removing slag from the hole. Furnaces of different capacities were used

Jan 1, 1935

By Charles H. J. Patterson

When coal is deposited on the decks of pneumatic tables, all fine particles clinging to the larger pieces are blown free by the air. Inasmuch as the air retains an appreciable residual velocity after passing through the bed of coal, it is capable of suspending particles of goodly size. This velocity is dissipated gradually and, unless confined, can readily extend beyond the limits of the plant. Today the ideal in the design and operation of pneumatic cleaning plants is not that they be no dustier than the ordinary tipple, but rather that they be as clean as an office or shop. This degree of perfection may not yet have been attained in any commercial plant, but it is not impossible of achievement. Not until recently has the recirculation principle been applied to pneumatic separating plants. In the writer's estimation, it has not yet been proved entirely satisfactory in commercial installations. A serious obstacle lies in the fact that it is practically impossible to provide a truly closed circuit. The air circuits must be interrupted at certain points, if only for the introduction of raw material and for the recovery of the finished product. It is feasible to prevent the escape of polluted air at these points, but this can scarcely be accomplished without admitting additional air into the circuit. These additions of air are cumulative, which necessitates means for emitting to the atmosphere the excess while still carrying its objectionable burden, if provisions are not made for conditioning. If it must be provided at all, conditioning is frequently simpler and more economical if applied to the entire volume of air involved. This procedure eliminates the extra initial cost and operating expense of the closed system. Crane Cheek Experiments The first noteworthy commercial installation of pneumatic equipment was made in 1922, at the Crane Creek plant of the American Coal Co. of Allegheny County, at McComas, W. Va. Six tables for cleaning coal between the limits of and 3 in. comprised the initial installation. Dust was collected by hoods connected by a system of ducts to exhauster fans. In this installation the unit dust burden was small, owing to the removal of fines from the feed by vibrating screens.

Jan 1, 1931

By Daniel R. Shawe

Ore deposits of the western U.S. are divisible broadly into two genetic groups, a smaller one that fits the plate tectonic model of subduction and a larger one that appears unrelated to subduction. Some of the middle Paleozoic and lower-middle Mesozoic ore deposits in the western U.S. are associated with eugeosynclinal rocks and lie a few hundred kilometers west of reconstructed continent margins. These deposits probably formed as a result of subduction beneath oceanic or thin continental crust that was analogous to subduction predicated for the Kuroko massive sulfide deposits of Japan. Some middle Mesozoic porphyry copper deposits may have formed east of the continental margin when subduction-generated magmas were emplaced high in continental crust in a manner analogous to subduction-generated magmas that formed the Andean porphyry copper deposits. Most Cretaceous-Cenozoic ore deposits lie in a broad region extending many hundreds of kilometers east of the continent margin and characterized by conjugate tectonic zones, high terrestial heat flow, and low seismic velocity in the upper mantle. The deposits likely were formed in relation to magmas generated along the conjugate tectonic zones during differential northwestward drift and internal wrenching of the continental plate.

Jan 1, 1978

By C. K. Leith

The ores of the region are contained in rocks of pre-Cambrian age, which, for most of the country up to recent years, have usually been referred to as “crystalline schists” or “crystalline complex;” and regarded principally as a metamorphosed basement-unit upon which the sedimentary rocks, beginning with the Paleozoic, were laid down. In the Lake Superior region this pre-Cambrian complex presents an' unusual variety of rocks with determinable relations. It has been possible, with the large expenditures which the magnitude of the iron-mining industry warrants, to work out their stratigraphy to a larger degree than bas been possible in almost any other area of pre-Cambrian rocks. [The portion here omitted contains descriptions of the Archean, Algonkian, and Keweenawan rocks of the several districts, their structure, distribution, correlation, and succession. Table I. and the geological map of the Lake Superior region belong to this portion, but are here reproduced on account of their value as guides to the readers of the rest of the paper.] The simplest and clearest conception of the pre-ambrian succession for the Lake Superior region may perhaps be obtained by thinking of it as primarily divided into six series-Keweenawan, Upper Huronian, Middle Huronian, Lower Huronian, Keewatin, and Laurentian-all but the last two separated by unconformities of varying and disputed relative im-

Jan 1, 1913

Nature: Man is but one of the creatures which in- habit the earth, a dust speck in the universe. Thinking man has been concerned with his place and purpose in the universe since the earliest Egyptian and Chinese philosophers. Ancient creeds, as well as modern religions and philosophies of life, were concerned with the same problem. While such considerations and concepts have been valuable, theoretical philosophizing and dogmatic concepts are inadequate for a satisfactory solution of world problems of today. The concepts of man and life and their ultimate purpose should be sought in the relations of intelligent man to man and their relation- ship to the physical world. The quintessence of nature's accomplishment-man- is also the greatest disturber of nature and the greatest enemy of his own kind. While his spirit and mind defy and overcome natural limitations, his physical self is controlled by the same basic biochemical laws that govern any other form of living matter. This paradoxical duality of human voluntary and involuntary relations to nature is the source of the perpetual conflict between mind and matter. Therefore, the higher the spiritual evolution and perfection of the individual's mind, the greater and deeper the conflicting elements in their expression; and conversely, the simpler the mind or the mental and spiritual heritage, the less is the individual concerned with the conflicting elements.

Jan 1, 1950

By George E. Roberts

The maintenance of the common gold standard is the most important cooperative undertaking in the world. The war broke up this relationship and brought about a state of great disorder in the currencies and exchanges. After the war the countries all began to grope their way back to the gold standard as the best means of establishing trade and financial relations with each other. With this movement began a general decline in commodity prices. The question has been raised whether the world's return to the gold standard was not forcing prices back to the prewar level. Also, the question is raised whether the world has not outgrown the supply of gold as the basis of credit. Because Europe readjusted its monetary units to conform to the higher level of prices there is no pressure on prices on this account. Furthermore, a large amount of gold formerly in hand-to-hand circulation passed out of circulation and has been added to the central bank reserves. The gold reserves of 36 countries increased approximately 100 per cent from the outbreak of the war to June 30,1930. The increase is much larger than the average increase of prices in any of the important countries, at any time since 192.5. As gold in the central banks of issue is far more effective for all business purposes than gold in circulation, the gold scarcity argument has little basis as applied to this time. The abnormal distribution due to the war was to the disadvantage of business everywhere. Credit was scarcer and dearer in some countries. The inflation in this country might have been greater had the production of gold been greater. The argument supporting the theory of a scarcity of gold assumes as fundamental that general price changes must be accounted for by changes in the price equation on the side of money. This is disproved in every period of business depression. A downward price movement is characteristic of every period of business recession. Important discoveries of gold must be made even to maintain present gold production, in the face of which the world's business is bound to continue increasing. It cannot be doubted that some way will be found

Jan 1, 1931

By R. E. Sinke

Demerara Bauxite Co. in British Guiana has come a long way in tackling the problem of stripping and removing overburden. When the company started mining in 1917, overburden was hand-loaded into carts pulled by donkeys. Since then it has been recognized that overburden removal is one of the greatest problems. Over the past years a great quantity of equipment has been purchased, discarded as it became obsolete, and replaced with better and cheaper tools. The policy has kept the company's overburden removal costs within reason. Accurate records of costs per cubic yard and cubic yards per hour per unit have been kept for many kinds of equipment. Walking draglines and hydraulicking equipment are the key approaches to the current operation, but shovels, tractor-drawn wagons, self-propelled rubber tired scrapers, and tractor-scrapers still have limited applications. Mackenzie, operational headquarters of the Demerara Bauxite Co. Ltd., is on the Demerara River, 65 miles from Georgetown, British Guiana. Ore treatment and ship loading facilities are at Mackenzie, head of navigation for ocean-going vessels and the mines are located 7 to 40 miles farther upstream.

Jan 4, 1955

By P. LaRochelle, K. Y. Lo, A. L. Tamuly Phukan

In many civil or mining engineering works, the stresses and deformations of natural or excavated slopes due to the combined effect of self-weight and initial stresses are of interest. Because of the mathematical complexities of this problem, however, no complete exact solution exists for the simplest case, that of assuming the stress-strain relation of the rock to be perfectly elastic. Efforts have therefore been directed toward numerical and experimental technique. The stresses within an elastic slope have been obtained by LaRochelle,1 using the photoelastic and finite difference method to determine the difference and sum of principal stresses. Subsequently, Finn,2 Hoyaux and Ladanyi,3 and Duncan and Dunlop4 attempted to solve the same problem by using the finite element method. The problem was also investigated by Brown and Goodman5 and Brown and King6 who emphasize the importance of the effect of loading or unloading procedure on the stress distribution within the slope. Although the geometry of the slope and the boundary conditions involved are identical or similar, the results obtained by these various authors by no means agree. It is therefore necessary to review briefly the results of elastic analysis in order to lend credence to the methods used in the solution. Although the stress-strain behavior of some rocks may be reasonably approximated by the elastic modrl, other rocks generally exhibit an elasto-plastic behavior with strain hardening or strain softening as shown in Fig. 1. Experiments show that for most rocks, the stress-strain relationship is approximately linear from the origin to the point P (neglecting the small concave region under low stresses). At P, the curve deviates

Jan 1, 1970

By R. S. Barneyback

Not much more is known about concrete today than was known to the Romans. For all the research only better tools have resulted to measure the quality of the materials that go into it." In this paper "some of the materials for lightweight concrete and their characteristics are considered and effort is made to indicate their effect on the end result — a structure of lightweight concrete." Lightweight concrete had noble beginnings. It is believed that the first specification for lightweight concrete was written by the Roman Emperor Hadrian in the early years of his reign, 117-138 AD. Hadrian, was an engineer by trade and an Emperor by adoption. He took considerable interest in the structures sponsored during his reign, even to the point of working out the structural details and preparing working drawings for some of the more prominent works in the vicinity of Rome. In order to reduce the dead weight of the 140 ft diam dome of the Pantheon he specified that the lightweight structural concrete members supporting this concrete and tile composite dome were to be fabricated from a concrete containing pumice and scoria. Still standing after 18 centuries of abuse, this structure has been described as the master effort of a great structural genius, the ultimate achievement of Roman engineering skill.' The Romans were the first to employ many concrete techniques we think of as modem innovations. Some unnamed superintendent noted that when a carefully measured amount of pigs blood was measured into each batch of concrete during mixing, the concrete was more durable and exhibited much better resistance to freezing and thawing climates. He no doubt, attributed this success to the appeasement of one of the gods who in return provided protection for the building containing this sacrificial offering in its walls. It is known today that the blood-entrained air in the concrete tends to make mixtures more workable, resistant to moisture penetration and more resistant to frost damage.

Jan 1, 1964

By Robert H. Dickson

Limestone replacement and contact metamorphic orebodies are 80 irregular that sampling and estimating are far less. exact than in more regular types of deposits; both the mineralized masses and the lenses of ore within them are extremely irregular. So much development work is required to find the ore that the expense of blocking out great tonnages is prohibitive; furthermore, the rock near these orebodies is so heavy that drifts or raises cannot be kept open for many years without excessive repairs. As a result, few mines in limestone have more than three years supply of ore in sight. As most of the ore, is developed by stoping— not by drifting, raising, or drilling—estimates of ore developed do not indicate the total amount of ore that may be expected; they simply indicate the relative condition of the mines. But even if they are to do this, they must be made according to a fixed plan, intelligently carried out. The estimates of ore in the Calumet & Arizona Copper mines, Warren District, Ariz., have been of much value to those who plan the mining and development work. This paper describes the methods of sampling and estimating used in these mines. Sampling Samples are taken in various ways and depend on the condition of the working and the purpose for which the sample is to be used. Drifts, crosscuts, and raises are sampled by channels or by taking a grab off each mine car as it is filled. Stopes are usually sampled by drill holes or by taking a representative sample off each mine car; the latter, or chute, sample is by far the best sample. All workings are studied periodically by an engineer, who makes graphic and detail notes of the geologic structure, as shown in Fig. 1. The daily car tally and assay of each particular working is added to the same sheet opposite the material it represents. These sheets make a permanent record, showing the exact boundaries as well as the grade of ore in all workings.

Jan 1, 1925

By C. E. Bailey

In this our fifth year of actual mining, a resume of our methods of mining may prove of interest. Our conditions are radically different from those of other districts; and we are just commencing to be able to draw conclusions regarding the systems in use. The ore-bodies of the range lie in a blanket-formation varying in width from 200 or 300 feet to over half a mile, and in length from 500 feet to more than 2 miles. It is practically horizontal in bedding, but in places has a dip of as much as 7 feet in 100 for a quarter of a mile. The top of the ore is in most cases nearly level, although local rolls make the back (or top of the ore) vary to the extent of 10, or in rare cases 20 feet, and very frequently there is a general slope of the top of the ore, as well as the bottom, which makes it impossible to mine it all from one level. Taking the average of long stretches, the side-walls may be described as quite regular; but local deflections make it necessary to prospect for the wall-rock, and in drifting underground it is common to drive along the sidewalls, uncovering them almost continuously, and thus making sure that no large pockets of ore are missed. The dip of the side-walls varies greatly, but an average is probably between 45' and 60°, sloping inward at the bottom, making the general shape of the ore-body not exactly a basin, but more nearly a trough, usually with a longitudinal trend and sloping sides, and ore much the deepest at the center. As to rock-occurrences inside the ore-body, the properties most largely worked may be said to be particularly free from rock, although much trouble is occasioned by bunches or small masses. In most cases these are not properly described as " horses" of rock, since they have neither continuity nor regularity of trend, but are offshoots connected with the side-walls or bottom.

Jan 1, 1898

By Charles W. Wright

At most mines where large tonnages are handled, "bulldozing" or secondary blasting is an important and costly operation. To reduce the large blocks from primary blasting operations or stoping so that they will be small enough to pass through the chutes into the cars at the haulage level, and not too large for the crushing plant, requires blasting. Often this is done by placing a few sticks of dynamite on top of a block with or without a capping of mud, but to consume less dynamite and to promote safety, most secondary blasting is now done by blockholing, or the drilling of holes 6 to 12 in. long in the blocks, using only a part of a stick of dynamite per hole. Regardless of the method of blasting, however, the term "bulldozing chamber" is applied to the room where this work is done. Bulldozing chambers permit secondary blasting at all times in a safe place without disturbance to the other mining operations. The chambers are usually high above the haulage level and well below the stope level or open-pit floor. In most instances the material is passed through a grizzly in the bulldozing chamber, but sometimes no grizzlies are used. One to four raises extend from the chamber to the stope floor and one or two from the haulage level to the chamber floor. Occasionally large slabs of ore or rock choke the raises above the bulldozing chamber, and these have to be blasted by attaching a bundle of dynamite sticks on the end of a long pole and placing them up in the raise between the pieces causing the choke. This is called "chute-blasting." To give a picture of the progressive developments in the use of the bulldozing chamber, a few typical mines that show the application of this method to both metal and limestone mines have been selected for description here. Limestone mines have been included because many metal miners do not realize to what extent the nonmetallic, or rock, miners' are now applying metal-mining methods successfully in their operations. The bulldozing chamber is the "neck of the bottle" for some mines.

Jan 1, 1937

By B. H. Sage, W. N. Lacey

Variations in the composition of the liquid phase of natural reservoirs which are continuous through significant ranges in elevation have been noted by petroleum technologists. In general, there is a greater gas-oil ratio and the gravity of the oil is higher in production from the upper parts of the formation. In the present paper the possible changes in composition with elevation which would result from the attainment of thermodynamic equilibrium in a uniform gravitational field have been evaluated for a naturally occurring hydrocarbon liquid, a binary hydrocarbon liquid phase and a binary hydrocarbon gas. The results indicate a progressive decrease in the mole fraction of the components from methane through the butanes with increasing depth, accompanied by a corresponding increase in the amount of the heavier components making up the system. The magnitude of these variations is perhaps insufficient to explain completely the variations in the properties of the liquid phase that are encountered at various elevations within a particular producing horizon. However, the changes are significant and the treatment presents an example of the application of thermodynamic data to the evaluation of the properties of hydrocarbon fluids under the conditions approaching those encountered in natural reservoirs. Theoretical Considerations Muskat1 has discussed the work of earlier authors relating to the equilibrium relationships of multicomponent systems in a gravitational field. He also presented explicit solutions for several cases and discussed the physical significance of gravitational concentration gradients. In engineering work it is customary to consider the pressure, the temperature and the composition of a phase to be the independent variables sufficient to establish its state. This procedure neglects the effect of gravitational or other types of fields upon the energy associated with the system and assumes, among other things, that the pressure is uniform in

Jan 1, 1939

By W. N. Lacey, B. H. Sage

Variations in the composition of the liquid phase of natural reservoirs which are continuous through significant ranges in elevation have been noted by petroleum technologists. In general, there is a greater gas-oil ratio and the gravity of the oil is higher in production from the upper parts of the formation. In the present paper the possible changes in composition with elevation which would result from the attainment of thermodynamic equilibrium in a uniform gravitational field have been evaluated for a naturally occurring hydrocarbon liquid, a binary hydrocarbon liquid phase and a binary hydrocarbon gas. The results indicate a progressive decrease in the mole fraction of the components from methane through the butanes with increasing depth, accompanied by a corresponding increase in the amount of the heavier components making up the system. The magnitude of these variations is perhaps insufficient to explain completely the variations in the properties of the liquid phase that are encountered at various elevations within a particular producing horizon. However, the changes are significant and the treatment presents an example of the application of thermodynamic data to the evaluation of the properties of hydrocarbon fluids under the conditions approaching those encountered in natural reservoirs. Theoretical Considerations Muskat1 has discussed the work of earlier authors relating to the equilibrium relationships of multicomponent systems in a gravitational field. He also presented explicit solutions for several cases and discussed the physical significance of gravitational concentration gradients. In engineering work it is customary to consider the pressure, the temperature and the composition of a phase to be the independent variables sufficient to establish its state. This procedure neglects the effect of gravitational or other types of fields upon the energy associated with the system and assumes, among other things, that the pressure is uniform in

Jan 1, 1939

By W. J. Reagan

Many factors enter into the manufacture of basic open-hearth steel of high quality. Perhaps the two most important are temperature and the iron oxide content of the metal. If we can control these two factors we can essentially control basic open-hearth practice. SOURCE AND EFFECT OF IRON OXIDE Earlier investigators, especially Herty and his associates, have shown that iron oxide is introduced into the open-hearth furnace in four ways:' 1. By oxidation of the scrap by furnace gases. 2. By decomposition of the limestone. 3. By oxidation of the iron oxide in the slag by furnace gases. 4. By direct addition of iron ore to the charge. We also know that the speed of operation of an open-hearth furnace depends, for a given charge and given combustion conditions, on the rate at which iron oxide will diffuse from the slag into the metal. The rate of diffusion depends upon a number of variables, such as iron oxide content of the slag, slag viscosity, etc., which also depend upon the amount of iron oxide in the metal, amount of carbon present, temperature, and so forth. For a given carbon and a given temperature, the iron oxide content of the metal is in proportion to the iron oxide content of the slag. This fact can be easily verified by analysis of slag samples taken as described by Herty.2 It is preferable to take these samples just before deoxidetion. In killing the steel samples with aluminum it is desirable to use aluminum rod of 99 per cent purity; ordinary commercial aluminum rod with a purity of approximately 92 per cent is not satisfactory. In drilling these samples it is also essential to take the largest amount of drillings possible. This gives more accurate results because it eliminates spotty segregation of A12O3.

Jan 1, 1932

By A. H. Bromly

The small agricultural village of Santa Barbara, in the State of Guanajuato, has been the center of spasmodic tin-mining operations during recent years. The deposits, so far as I know, are unique, and a few brief notes may be of interest. Santa Barbara, about 12 miles west of San Felipe station on the Mexican National Railway, and at an elevation of 2,400 m. above sea-level, is situated in a flat valley extending east and west, and bounded north and south by broken rugged hills rising about 330 m. above the general level of the valley. Tin-mining operations have been conducted at the Queensland mine, near this village. A small concentrating-mill was erected and attempts were made to smelt the ore in reverbera-tory furnaces. The country-rock of the district for many miles is rhyolite of great thickness. There are some local variations due to differences in cooling, or subsequent alteration or impregnation; but throughout the whole district the principal constituents of the rocks remain the same, viz., free silica, orthoclase-feldspar and sanidine. The latter is especially marked. The crevices and joints of the rock are frequently filled with calcedonic and opalescent quartz. The ore-formation at the Queensland mine is of an unusual nature, consisting of cracks in the rhyolite which have been filled with clay. This phenomenon is largely developed over a width of from 80 to 100 m., in which the principal fissuring follows an approximate direction of north and south. The average dip ranges between 70 and 80 degrees. Some of the fissures hold sufficiently true for a time to afford the impression that they are due to dynamic causes, or earth-movement. This may be true of some of the north by south fissures; but considering

Jan 1, 1906

By H. Shaw

IT is now generally recognized that the gravitational method of geophysical surveying is a valuable aid in elucidating the geological structure of the subsoil and enables the practical geologist to deduce the presence of useful deposits. The particular suitability of the torsion balance to the location of large and important subterranean structures has given rise to a wide. application of this method by many of the important oil companies in their search for future supplies, and so intense have been these efforts that little has been heard of the method in other connections, with the exception of occasional references to its application in the location of hidden deposits of metallic ores, salt and lignite, and a number of accounts of its use in the elucidation of geological structures. Its success in the location of salt domes is well known, and. establishes it as one of the most important of the geophysical methods, especially for the indirect location of oil. In the British Isles, however, no large occurrence of oil is likely to be revealed, and here the practical application of the gravitational method has been restricted almost entirely to the search for ores. This type of survey possesses well marked characteristics, and presents a gravitational problem that has necessitated the development of a special and probably unusual plan of campaign, full details of which it is hoped will shortly be published. The problems and difficulties encountered in this work are of necessity fundamentally related to those met with in the search for oil by means of the torsion balance, but they also possess several special and distinctive features which undoubtedly differentiate them from the obstacles confronting the oil prospector, and which call for special consideration and treatment.

Jan 1, 1928

By E. P. Valby

A method is presented in which the hydrocarbon weight fractional analyses of the well effluents from a true gas-tip-portion well and a true dark-oil-ring well furnish the basic data for determining the properties of any mixture of production from the two sources. The effect of injected gas on these properties can be computed. Comparison of similar properties of a given well effluent to the properties of mixtures of the basic well effluents will give the relative amounts of production from the two sources and injected gas. Presentation of Problem Oil fields having an area of gas-cap, or light-oil production, over the dark-oil area present a problem of increasing gas-oil ratios during the production of an oil well. The use of pressure maintenance in a field such as above, or a cycling project, wherein residue gas from an absorption plant is injected into the reservoir, adds to the problem, because a part of the increased gas-oil ratio may be due to the production of injected gas. The usefulness of a means to determine the amount of injected gas in a well effluent led to the development of a method in which well-effluent analyses of a true gas-cap-portion well and a true dark-oil-ring well furnish the basic data needed to determine whether injected gas of a known composition is present in a given well effluent. Development op Method The method presented herein is based upon the principle that if two fluids, or well effluents, having different properties are mixed in known proportions by weight, • the properties of their mixtures can be computed. Conversely, if these basic data are known, the properties of a mixed well effauent can be used to compute the relative amounts of each type of well effluent in the mixture. A convenient way of making these computations is to have the fractional analyses of the base well effluents and mixtures expressed in weight fractions The mathematical equations expressing the properties of mixtures will be developed for a two-component system consisting of the well effluents from the dark-oil ring and the gas-cap area. The added effect of injected gas, a third component, will also be developed. The following assumptions have been made in developing the method: 1. The gas-cap and dark-oil fluids exist initially in separate portions of the reservoir. 2. The fluids in each portion exist in a single phase at pressures above the saturation pressure for the dark-oil fluid. 3. The composition of each fluid is substantially constant throughout its respective portion of the reservoir. 4. Changes in reservoir pressure and temperature will not change the composition of the fluid entering the well bore. 5. The injected gas displaces original gas-cap fluid 100 per cent. •• 6. AS the injected gas travels through a

Jan 1, 1945

By Samuel L. Hoyt

This paper gives a brief description of an investigation made several years ago on the diffusion of zinc into copper. The material for that study was furnished in the form of thin copper strips coated with zinc. The result was required rather quickly and at not too great an expense, and especially information was desired as to the rate at which zinc would diffuse from the zinc coating into the copper and the temperature at which the operation should be carried out. A study of the requirements of this problem indicated that the solution might be secured by means of six determinations. This is the smallest number that will give the information desired and, at the same time, furnish checks on the accuracy of the determinations which justify an abbreviated experimental program. This does not count a preliminary test which was designed to give some idea of the correct temperature to use. The minimum number of temperatures that can be used is two. Knowing the rates of diffusion of zinc into copper at two properly chosen temperatures, it is possible to calculate the rate for any other temperature, and also to check the accuracy of the determination by means of the heat of diffusion, which is calculated from the effect of temperature on the rate of diffusion. The minimum number of determinations at any one temperature is three. The amount of diffusion which occurs at a fixed temperature is definitely related to the time of diffusion, so that by determining the amount of diffusion for three different time intervals, this relationship may be established and possibly a check on the accuracy may be secured. This accounts for the six determinations or experiments, and suggests the logical plan of the work. The check used here is not generally applicable to diffusion phenomena, but it seems to hold closely enough for the limited amount of diffusion in this investigation to justify its use. The samples used were 5 to 6 mils thick and about 1 in. square. They were placed between iron blocks and set in the hot zone of a nichrome furnace which had been brought to the desired temperature Time was taken from the moment the samples reached the furnace

Jan 1, 1929