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By H. S. Munroe

The accompanying figures illustrate the dumping-device used at the new dressing works of the St. Joseph Lead Co., at Bonne Terre, Mo. It is a dumping-cradle, of a type much used abroad, in which the car is turned upside down to discharge its load. The main

Jan 1, 1889

By W. A. Ver Wiebe

The year 1939 in Kansas, with a production of 57,944,300 bbl. from 19,669 wells, shows a slight recession from the peak of oil production reached the previous year, when slightly over 59,000,000 bbl. of oil was marketed. The previous peak had been reached in 1917 with 45,451,000 bbl. marketed. Another still earlier peak had been reached in 1904, when slightly less than 5,000,000 bbl. was produced and sold. The production of gas probably reached a new peak during 1939 with a total of over 69 billion cubic feet. Between the peak of the year 1908, when over 80 billion cu. ft. was produced, and that of 1939 the production dropped to 16 billion cu. ft., in the year 1921. During the year 1458 wells were drilled. This figure is somewhat lower than that given in several trade journals, because it does not include wells that were deepened or recompleted in a different geological horizon. Nearly 75 per cent (1029) of the total number of wells were completed as commercial oil wells (824 in western and 205 in eastern Kansas). The commercial gas wells completed number 71, of which 24 are in eastern Kansas and 47 in western Kansas. The remaining completions include 154 dry holes in eastern and 204 dry holes in western Kansas. Based on daily potential capacity the new discoveries of the year accounted for a cumulative initial production of 264,000 bbl. in eastern and 1,158,827 bbl. in western Kansas. It is interesting in this connection to note that the number of wells completed in the state rose gradually to a first peak in 1904, when 2782 were drilled. The number dropped off rapidly to 368 three years later, but rose to the second and highest peak in 1918, when 4671 wells were completed. In the period between 1904 and 1912 more gas wells than oil wells were completed. Between the high peak of 1918 and the somewhat lower peak of 1937, the low point was reached during 1931 with the completion of only 470 wells. In the matter of new pools discovered, Kansas again ranks high. The exact number depends somewhat upon the interpretation of a "new" area—whether it should be called a new pool or a long extension of an older pool. In some places this determination cannot be made until more wells are drilled within the area. Therefore, the figures given

Jan 1, 1940

By W. A. Ver Wiebe

The year 1939 in Kansas, with a production of 57,944,300 bbl. from 19,669 wells, shows a slight recession from the peak of oil production reached the previous year, when slightly over 59,000,000 bbl. of oil was marketed. The previous peak had been reached in 1917 with 45,451,000 bbl. marketed. Another still earlier peak had been reached in 1904, when slightly less than 5,000,000 bbl. was produced and sold. The production of gas probably reached a new peak during 1939 with a total of over 69 billion cubic feet. Between the peak of the year 1908, when over 80 billion cu. ft. was produced, and that of 1939 the production dropped to 16 billion cu. ft., in the year 1921. During the year 1458 wells were drilled. This figure is somewhat lower than that given in several trade journals, because it does not include wells that were deepened or recompleted in a different geological horizon. Nearly 75 per cent (1029) of the total number of wells were completed as commercial oil wells (824 in western and 205 in eastern Kansas). The commercial gas wells completed number 71, of which 24 are in eastern Kansas and 47 in western Kansas. The remaining completions include 154 dry holes in eastern and 204 dry holes in western Kansas. Based on daily potential capacity the new discoveries of the year accounted for a cumulative initial production of 264,000 bbl. in eastern and 1,158,827 bbl. in western Kansas. It is interesting in this connection to note that the number of wells completed in the state rose gradually to a first peak in 1904, when 2782 were drilled. The number dropped off rapidly to 368 three years later, but rose to the second and highest peak in 1918, when 4671 wells were completed. In the period between 1904 and 1912 more gas wells than oil wells were completed. Between the high peak of 1918 and the somewhat lower peak of 1937, the low point was reached during 1931 with the completion of only 470 wells. In the matter of new pools discovered, Kansas again ranks high. The exact number depends somewhat upon the interpretation of a "new" area—whether it should be called a new pool or a long extension of an older pool. In some places this determination cannot be made until more wells are drilled within the area. Therefore, the figures given

Jan 1, 1940

By C. T. Bischoff

DURING the past few years geochemical testing for traces of heavy metals in water, soil, rock, and vegetation has aroused increasing interest. Various techniques for field and laboratory determinations have been described in the literature, as have some of the results of application. However, little information has been published regarding application to glacial terrain. Over 90 pct of the Canadian Shield is overburdened, resulting in high costs for mineral exploration once the outcropping ore deposits have been found. This has been largely responsible for the widespread application of mining geophysics in Canada, permitting concentration of effort on area or zones considered most favorable. However, geophysical interpretation has its limitations, since at least 90 pct of the structures indicated thereby contain no valuable minerals. A more direct approach is therefore highly desirable. If underlying base metal mineralization can be detected by sampling soil or vegetation at moderate cost this should prove of great help in locating new discoveries or extending known ones. A large proportion of Canadian ore deposits contain appreciable copper or zinc, even where these are not the principal economic metals. Consequently the field of application is a broad one.

Jan 1, 1954

The Motor Truck Sections of the 20th Annual Automobile Shows of 1920, to be held in the 8th Coast Artillery Armory, New York, Jan. 3 to 10, 1920, and in the International Amphitheatre, Chicago, Jan. 24 to 31, 1920, will he the largest and most comprehensive exhibitions of the kind ever held. Approximately 125,000 sq. ft. of exhibition space has been alloted at each place and upward of seventy makes of motor trucks, together with trailers, pacts and accessories will be dis-played. In conjunction with these expositions, Highway Transport Conferences will be held, with sessions each afternoon and evening. Every important phase of highway transportation will be discussed by men recognized as qualified authorities. Various talks will he il-lustrated by motion pictures and stereoptican slides. Members of the Institute may apply for complimentary tickets to-S. A. Miles, Manager, 7 East 42d Street, New York City.

Jan 12, 1919

B. F. TILLSON,* Franklin Furnace, N. J.-I would like to ask Major Yerkes if he will not give us more examples of the tests than are contained in the printed pamphlet. It would be of great interest to study them more carefully. ROBERT M. YERKES, Washington, D. C.-The reason for not reproducing the methods in any public print is that it lessens their value and necessitates the preparation of new test materials. BRADLEY STOUGHTON, New York, N. Y.-I hope that this matter will be of so much interest to the members of the Institute that the Directors will decide to appoint a committee which can bring further results of this practice before us. I understand that Columbia University, at least in some departments, has already adopted the B and A tests and is using them. I understand that some industries have considered seriously the question of grading their employees in accordance with

Jan 4, 1919

A novel method of reconditioning vertical rock openings which are on the verge of collapse has been developed, ant1 a world patent applied for, by LKAB, the Swedish iron ore mining company. Without anyone descending into the dangerous opening, workers can place concrete reinforcement in the unstable section using sand-filled canvas tubes which LKAR development engineers are calling "stockings." First application of the new technique was in several inclined ore pockets which form part of the underground crushing and loading station at LKAB's Kiirunavaara mine in Swedish Lapland. LKAB experience demonstrated that with other methods it took about three months to repair a pocket, and neighboring pockets had to be closed while repairs were underway. With the new stocking method, the work was completed in three weeks with no disruption of nearby activities. Production losses amounted to 10% over the three-week period, as opposed to 30% with other methods. The simplified technique could save millions of dollars in underground maintenance, according to LKAB.

Jan 11, 1978

By William P. Blake

The adaptation of aluminum to the construction of portable instruments of precision, where lightness is important, is well illustrated by the double reflecting and repeating circle, the invention of Captain Charles Hervey Tomnshend, of New Haven. One of these instruments, now exhibited to the members, has just been completed by Stackpole & Bro., of New York, and is made of aluminum, with the exception of a few minor pieces and a portion of the handle. This instrument is intended for use in a boat, and to be held in one hand like a sextant; and as it is a complete circle, lightness of the material becomes more important. The whole instrument, as shown, exclusive of the eye-pieces and the handle, weighs only one pound, or about one-third of the weight of a sextant of the usual construction. The circle, about nine inches in diameter, was cast in one piece from metal furnished by the Pittsburgh Company.

Jan 1, 1890

Following the usual custom, three meetings are planned for the year. The Mid-Continent meeting will be held at Oklahoma City, Okla., Oct. 7 and 8, and the California meeting is planned for Los Angeles, probably also early in October. A program along the usual lines is under way for the annual New York meeting. Discussion and planning of the year's activity started in March. An effort is under way to secure papers dealing with some overlapping phases of engineering, petroleum geology, geophysics, law, economics, refining, etc. The main reason for attempting a program along these lines is the belief that unusually interesting technical papers can be obtained. The degree of specialization in the technical and related fields has permitted but few individuals to develop a sufficiently comprehensive viewpoint. Also, at times the developments in a particular field are capable of giving great stimulus toward much needed solutions of difficult problems in others fields of activity. With the coming of the period of restriction of production to market demand, many changes have occurred in policy and technique of petroleum production. Some changes have been advances, others have been of retrograde nature. It seems doubtful whether the adjustment to the condition of excess producing capacity has been complete or sound in some major respects. Many changes are in progress and others need to be initiated. The industry has excessive producing capacity so far as immediate market demand is concerned, but reserves for several years hence are generally believed insufficient. Exploration and discovery should go forward but development should proceed with caution and under control. Property rights should be clarified and protected for the new condition— without excessive cost for drilling wells that serve no purpose except that of giving some protection to property rights at the cost of an increased price to the consumer. Under the more steady condition of assured supply for the immediate future, as compared to the hand-to-mouth condition of wide-open production, a greatly advanced technique of development and production is possible and is being developed. Great progress has been made, but much remains to be done. Along some important lines progress can be effected only by better understanding between the engineer and the geologist, the lawyer, the politician, the geophysicist, etc. There is need

Jan 1, 1937

By Boris J. Kochanowsky

In a mobile crushing unit system trucks are replaced by a conveyor, which results in a continuous, almost fully automated operation with all its attendant advantages. Because of new designs for large mobile crushing units that have been placed on the market, the use of these plants has increased significantly during the last three years. Gains in productivity and reductions in costs are vital to every mine operator, and the shovel-crusher-conveyor system is a powerful tool with which to achieve this goal. New Designs Increase Throughput While Reducing Size The basic concept of the shovel-crusher-conveyor scheme of operations is simple and sound, with the result that domestic operators are showing a growing interest in its application. A number of operators have been using small mobile crushing plants for several years, but large operators, in spite of considerable interest, have not been able to use this system because no mobile crusher capable of crushing 1000-2000 tph of rock loaded by a large shovel (6-12 cu yd) has been available. A suitable crusher must accept rock of the size handled by these large shovels, be simple in design, easily maneuverable, remotely controllable, and have price and maintenance costs not much higher than those for stationary crusher installations.

Jan 9, 1968

By Walter English

THE four papers making up this symposum have been prepared espe-cially for those who have no knowledge of seismograph prospecting. To many people mathematics is a formidable subject, and many are discouraged from studying seismograph prospecting under the mistaken assumption that the mathematical requirements are severe. In the papers presented here there is not a single mathematical equation. We believe that considerable competence in dealing with some of the most important problems of this work can be attained without any mathe-matical training whatever. At the present time, there is a real need for interpretation of results by persons thoroughly competent to bring geologic experience and imagination to bear on data that are subject to multiple interpretation from a strictly physical viewpoint. Likewise, those charged with the responsibility of planning seismo-graph exploration campaigns would do well to become familiar with as much as possible of the technical aspects of the work. They would then be in better position to judge of its success in individual cases. It has often been said that the seismograph is a new structure-finding tool for the geologists to use. Using a tool and using its product are two different things. One does not use an automatic screw-threading machine when he buys a box of screws at the hardware store. Neither does the geologist

Jan 1, 1939

By Louis P. Gignac

INTRODUCTION The selection of trackless equipment for underground mining can be a complex engineering problem due to the wide range of equipment sizes and operating modes. Computer simulation is particularly useful in estimating the performance of different systems for specific rock- handling problems. A hybrid simulator, incorporating some of the features of deterministic and stochastic simulation, was developed in order to handle not only queuing delays at loading and dumping points, but a1 so traffic interferences. Any number of vehicles can operate in any one of four basic modes (LHD, LAF, FEL, HFC) in parallel or in series. If the units use common roadways, loading and dumping points, certain operating delays will occur and be registered by the simulator and thus give a better evaluation of the marginal productivity of each additional unit. Based on a typical layout of drawpoints and ore passes for the sub-level stoping method, productivity and operating costs of different rock-handling systems will be examined. 1 . COMPUTER SIMULATION Numerous applications of computer simulations are reported in the 1iterature for various mining problems. Depending on the complexity of the system to be studied, simulation models were conceived with different degrees of sophistication. Three different types of simulators are generally recognized: stochastic, deterministic, and hybrid. Stochastic or Monte Carl o simulation randomly generates items, transactions, or events from some population defined by a frequency distribution and produces some expected future situations. Because this type of simulation is governed by the input of probability distributions, it requires a detailed knowledge of the system to be simulated; it implies expensive and time-consuming studies and reports to gene- rate this input information. A major short- coming of stochastic techniques is in new equipment evaluation, where the lack of data is unavoidable, and in new system design where the conditions are outside the range of the known historical behavior of the equipment. However, probabilistic simulation is almost essential for the study of cyclic queues and traffic problems. Deterministic simulation studies a system by generating performances on the basis of the mechanical capabilities of the vehicles and the physical limitations of the mining scheme. It is based on the engineering principle that the engine converts its energy into a rimpull at the wheels, which is in turn opposed by the rolling resistance and the grade of the ground; the machine is accelerated or decelerated until the tractive and resistive forces are in equilibrium, at which point it moves at constant speed. The information required by this technique, such as rimpull charts and equipment weight, is readily available from equipment suppliers. However, equipment performance at the mining site is also dictated by human and environmental conditions and changes with time and usage. For this reason, deterministic simulation generally overestimates the system capabilities; these must then be adjusted by efficiency factors based on observation and experience. Recently, hybrid simulation models, using both stochastic and deterministic techniques, have been built with some of the events generated stochasticly and others being deterministic. This compromising approach originated at the Pennsylvania State University. O'Nei1 (1966) designed a simulator for truck-and- shovel operations that allows for transportation from multiple faces to mu1tiple destinations. Each truck performs according to its mechanical capabilities while its loading and dumping time and its load fluctuate according to specific probability distributions. A major advance in the simulation of mining systems is due to Sanford's model (1969) of underground coal mining operations. The originality of the model is in the use of an Executive System Control which sets up the initial system, de- fines the operation conditions , and instructs continuously four sub-assemblies representing shuttle cars, trains, continuous miners , and conveyors, which in turn generate a feed-back of their movement to the Executive Control System for further instructions. The model has enough flexibility to simulate simultaneous and sequential jobs that characterize any dynamic system. Sanford's early work evolved slowly to what is known today as the Under- ground Materials Handling Simulator for coal mining (Manula, 1974).

Jan 1, 1981

By Donald Warren, J. F. Libsch

HIS investigation originated as a result of a pre-vious experimental study' of the magnetic properties of Fe-Co alloys fabricated by the powder metallurgy technique. Densities of powder compacts prepared for the magnetics investigation varied from 7.45 to 7.70 g per cu cm or from 93 to 95 pct of the experimental value of 8.08 g per cu cm for a fused alloy of the same composition.' While this range of density is considered sufficiently high for most applications, the highest possible density is to be desired for maximum magnetic properties. By applying a technique similar to the one described above to a pure electrolytic iron powder, Rostoker³ was able to achieve a density of 7.895 g per cu cm, which is the highest density ever reported for sintered iron. While Rostoker's work involved the sintering of an elemental powder rather than a mixture, it was believed that higher densities should also have been obtained for alloys using the above technique because of the recoining operation and the high sintering temperature. Consequently, it was decided to investigate the various factors affecting the density of this alloy with the idea that such a study might lead to higher densities and, as a result, powder alloys having magnetic properties identical with those of the fused alloys. It was believed that the principal reason that near-theoretical densities for the powdered alloy were not obtained was the interference of gases with the normal sintering mechanism. When present during the sintering operation, gases can exert several harmful effects: they can remain on the particle surface and interfere with surface diffusion and plastic flow; they can be released and, under certain conditions, expand the void spaces through gas pressure; or they can remain trapped in the pores and exert a hydrostatic pressure that retards elimination of the pores. Jones,4 Rhines,5 Goetzel," and others have given the effect of gases in the sintering of powder compacts an extensive treatment. Among the more important sources of gases in the sintering process are dissolved gases, adsorbed gases, air entrapped during pressing, and gaseous products of chemical reactions. During sintering adsorbed gases are partly released at a relatively low temperature, while those gases entrapped during pressing cannot escape until their pressure is increased sufficiently through increasing temperature to expand the interpartjcle openings. The remaining adsorbed gases, gaseous reduction products, and dissolved gases produce a similar effect at the higher temperatures. If, in the sintering process, gas evolution occurs after the interpore channels have been sealed, an exaggerated expansion of the void spaces results. This is particularly true if the temperature is high enough for extensive plastic flow. In his fabrication of powder bars from tantalum, Balke7 had to consider the effect of adsorbed hydrogen and provide for its escape during sintering by limiting the compacting pressure to a maximum of 50 tons per sq in. The effect of gases entrapped during pressing was first noted by Trzebiatowski8 when he found that gold and silver powders decrease in density with increasing sintering temperature if pressed at 200 tsi, while they exhibit the usual increase when pressed at 40 tsi. Recent investigators9-11 have also noted that entrapped gases have an effect on the expansion of copper compacts during sintering. Proper provision for the escape of gaseous products of reduction must be made in order to avoid deleterious effects. Myers" states that in the sintering of electrolytic tantalum powder, the temperature was gradually raised to 2600°F with a pause at 2000°F to permit reduction of the oxides. Experimental Details For the present study, 50 pct Co-50 pct Fe compacts in the form of circular disks 1½ in. in diam and 0.15 in. thick were fabricated by the pressing and sintering of a mixture of the elemental powders. It was decided to follow the sintering process by means of liquid permeability measurements, because it was thought that such measurements might serve as a measure of relative pore sizes, as well as a possible indication of the point at which most of the interpore channels become sealed. However, since the permeability as measured by the flow of a liquid, such as ethylene glycol, does not give an absolute indication of the point where the pores have become isolated, a method for determining the percentage of pores connected to the surface was set up. As an additional cross check on the permeability measurements, metallographic methods were used to study the relative pore size. Finally, the property of ultimate interest, the density, was measured. Raw Materials: The powders used consisted of an annealed, 99.9 pct pure, —150 mesh grade of electrolytic iron powder, and a 98 pct pure, —200 mesh grade of reduced and comminuted cobalt powder. The cobalt powder was not further processed either by hydrogen reduction or annealing. The screen analyses for the iron and cobalt powders are given in Table I, while the chemical analyses for each type of powder are listed in Table 11. Table 111 gives the hydrogen loss measurements for the powders according to the M.P.A. Standard Method and for a higher temperature as well. Preparation of Compacts: Equal amounts of the elemental powders were mixed by rotation for 1 hr and then pressed into compacts approximately 0.15

Jan 1, 1952

By Rudolf Bernhard

STATIC soil investigations with more or less heavy loads and extensive borings do not always have efficient results; also, they are very expensive. The new geophysical method of dynamic tests described herein is simple and cheap and avoids several disadvantages of the routine investigation, thus forming a useful supplement to the older methods and even at times replacing various static tests. The fundamental principle of dynamic soil tests consists in the appli-cation of artificial vibration. The technique employed is essentially geophysical in nature and in some respects is akin to seismic studies. Artificial vibration may be excited by centrifugal forces resulting from eccentrically supported rotating masses. The reactions of soil and structures caused by these vibrations may be measured. Their dynamic constants, such as amplitudes, phase speeds, damping, reflection, and interference effects, can be investigated. This geophysical method has been used for several years with increasing success. The results of these tests, summarized at the end of the paper, indicate that this method opens a new field for the practical engineer in investigating soils (capacity and formation), foundations, dams and structures, and especially buildings that must withstand earthquakes.

Jan 1, 1938

By Robert Bakish

VARIOUS aspects of structure-sensitive corrosion of single crystals and polycrystalline aggregates of Cu,Au have been presented in papers by the author, in association with W. D. Robertson. Prompted by some observations in the course of these studies, a new approach to the problem was undertaken. Results of these new experiments are reported here. Thin slices, less than 2 mm thick, were prepared from single crystals 3.5 mm in diam grown by the Bridgman technique. The crystals were homogen- ized for 300 hr at 850°C. Crystals with no deformation, crystals deformed in tension to the yield point, and crystals deformed 20 pct in excess of the yield point were used. Crystals of several different orientations were studied. Slices were immersed for one month in 2 pct aqueous solution of FeCl3 and, subsequent to this immersion, were subjected to bending. Immersion and bending were carried out at room temperature. The size and geometry of the crystals did not permit accurate data on the loads involved. A most unexpected result was obtained in the process of bending these slices of Cu3Au crystals normal to the (110) plane. Completely brittle be-

Jan 1, 1958

By John Tyssowski

IN 1925, Harry Howard Stout, then metallurgist for Phelps Dodge Corporation, while investigating the cleaning of cathode copper by various gases at elevated temper-atures below the melting point of the metal, observed in the laboratory that particles of pure copper heated in a closed tube filled with hydrogen seemingly "stuck together." By further investigation he found that there was actual crystal growth across the boundaries of the particles of pure metal; in other words, there was a complete new crystal realignment and growth throughout the newly formed copper mass. It was coalescence, not adhesion; the several parti-cles had become one unit. From this dis-covery has been developed the coalescence process, whereby copper of cathode purity is squirted out in semifabricated form from an extrusion press, by the appli-cation of about 30c0 tons pressure on a 10-in. piston. Stout decided that cathode copper pro-duced by electrolytic deposition was the logical source of the pure copper required for the coalescence process, but as there was no way of reducing the ordinary tough commercial cathodes to the small particles required he was confronted by a serious problem at the outset. Under his direction, this problem was solved by William H, Osborn and Harry Howard Stout, Jr. They developed the process and technique for producing cathode copper in brittle, friable form, and to them must be given the greater part of the credit for this phase of the development program as well as for that relating to the gas cleaning of the cathode particles.

Jan 1, 1940

By J. W. Snavely

THE high tension belt conveyor is introducing a new and tremendously expanded era of low cost bulk material handling. High tension belt conveyors are generally those installations involving very long centers, high lifts, or drops, in which the belts are stressed up to their maximum tension values, and further, where the belt construction provides tension capacity far beyond what is possible with conventional belt constructions. With these high tension installations, the magnitude of the forces involved demands careful refinement of accepted design practice in order to achieve optimum balance of all factors.

Jan 3, 1951

By H. D. Dahl, P. C. Thakur

This paper presents an analysis of a new tool for improved productivity in coal mining: the horizontal drilling system developed by Conoco/Consol. The analysis includes a brief description of the system; discussion of the three categories of advance exploration application of horizontal boreholes; and a survey of other special mining methods planned around long horizontal boreholes.

Jan 1, 1983

THE New York Petroleum Club has elected the following officers for the current year: Chairman, William B. Heroy; vice-chairmen, Edwin B. Hopkins, Warren. A. Sinsheimer; secretary, A. C. Hunter. This is the local section of the Petroleum Division. It holds monthly lunch-eons, usually in the rooms of the Railway Club.

Jan 3, 1927

By George S. Ansell, John B. Hudson, Stephen A. Koffler

The permeability of hydrogen through the a phase of palladium has been measured by a low pressure permeation technique under conditions such that bulk diffusion was the rate-controlling process. The observed permeability is described by the equation: J = 1.80 x 1O-3 P½exp(-3745)/RT) cc(stp)/sec/cm2/en over a range of hydrogen pressure, P, from 2.9 x 10-5 m Hg to 5.0 x 10-3 cm Hg, and over a temperature range, T, from 300" to 709°K. The fact that the permeability shows a square root dependence on pressure and a reciprocal dependence on thickness was taken as evidence that bulk diffusion, rather than surface reactions, was the rate-controlling process. The permeability data were used in conjunction with the solubility data of Salmon et al., to determine the diffusivity of hydrogen through palludium as: D = 4.94 x 10-3 exp(-5745/RT) cm2/sec There was no influence of sub structural defects observed over the temperature range employed. From the permeability data obtained, coupled with grain size measurements, it was concluded that the ratio of grain boundary diffusivity to bulk diffusivity was less than 105 over the range of temperature investigated. THE diffusive mass transport of hydrogen in the a phase of palladium has been studied previously by numerous investigators.' In spite of the large amount of attention this system has received, there is not good agreement between the results obtained in different investigations.' This is due in part to the fact that the mass transport was surface-limited during some of these studies, rather than being diffusion-controlled3-5 The reason for the disagreement in other cases is not clear. These studies made use of such techniques as rate of absorption from solutions6 and gases,' electrochemical potential,8 time lag,' and permeation10,11 to determine the mass transport behavior. Of these, the gas permeability technique is the only method which allows an easy test to determine if diffusion is the rate-controlling mechanism, thus eliminating the uncertainty regarding the limiting transport processes inherent in the other techniques. The two most recent permeability studies are those of Toda10 and Davis." Toda determined the permeability of hydrogen in the a phase of palladium over the temperature range from 170" to 290°C, and over the pressure range from 36 to 630 mm Hg utilizing a steady-state gas-permeability technique. Toda's result was: J = 1.41 x 10-3 P½ exp(-3220/RT) where J = specific permeability in cc(stp)/sec/cm2/cm, P½ = square root of the inlet pressure in (cm Hg)½, R = Universal gas constant, and T = temperature in deg Kelvin. Davis11 also employed a steady-state gas-permeability technique over the temperature range from 200" to 700°C and over the pressure range from 0.02 to 760 mm Hg. His result for the permeability of hydrogen in the a phase of palladium was: J = 3.15 x 10-3 P½ exp(-A440/RT) In the range of overlapping temperature for these two investigations, the values of the specific permeability calculated from the above two equations differ by a factor of about 1.8. In the present investigation, the permeation of hydrogen in the a phase of palladium was determined over a wide temperature range, 27" to 436oC, and over the pressure range from 2.9 x 10-5 to 5.0 x 10-3 cm Hg. This temperature range overlaps that of the previous investigations of Toda and Davis, but also covers the lower temperature range which has never before been investigated. The lower pressure range used here avoided the interaction between the dissolved hydrogen atoms observed at higher hydrogen concentrations.' MATERIALS The as-received palladium specimens were cold rolled from a casting and were supplied as 5.08 cm discs of 0.508 and 0.762 mm thickness. According to J. Bishop and Company specifications, the composition of the discs was 99.95 pct Pd, the balance being Cu, Ag, Au, and Ir. In order to obtain samples of varying grain size, the as-received discs were then heat treated. Sample 1 was treated for eight minutes in a nitrogen atmosphere at 810°C and then air-cooled. Sample D was heated first to 550°C in helium. The helium atmosphere was then immediately replaced by hydrogen and the temperature was slowly raised to 1220°C and held for 22 hr. The sample was then cooled to 550°C where the hydrogen was replaced by helium and the disc was further furnace-cooled to room temperature. Sample H was given the same heat treatment, only with hydrogen substituted for helium below 550°C. The reason that hydrogen was not used throughout the entire annealing cycle for samples D and H was to prevent the distortion encountered by low-temperature cycling in hydrogen observed by Darling." After these heat treatments were completed, the

Jan 1, 1970