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By Nathaniel Arbiter

T. M. Morris (School of Mines and Metallurgy, Rolla, Mo.)—Rate studies promise to help quantify flotation operations. The author's exposition of rate studies is therefore laudable. However his exposition of a second order rate equation rather than a first order rate equation is not convincing. It is important to use the correct equation, otherwise erroneous conclusions may be drawn. The data assembled by the author and plotted according to a second order rate equation can be plotted according to a first order rate equation. As a matter of fact much of the data used reveals that a second order rate equation is not applicable. According to the method used by the author for plotting data, the reciprocal of the slope of the line is the maximum possible recovery. Physically this cannot exceed 100 pct, yet several graphs yield maximum recoveries greater than 100 pct. For example: l—Curve 2, Fig. 1 yields a value of 120 pct; 2—Curve 2, Fig. 2 yields a value of 115 pct; 3—Fig. 7 yields a value of 110 pct. The real test of the graphical method is, as the author points out, whether or not the earliest points agree with a straight line. The second order rate plot does not fulfill this requirement. Fig. 10 shows the data used by the author to obtain Curve 2 in Fig. 1, plotted according to both a second and first order rate equation. Fig. 11 shows the two rate plots made from data published by Ludt and DeWitt.19 In Fig. 10 the first order rate plot gives a very good fit and obeys the boundary condition of passing through the origin. For the second order rate plot a straight line can be drawn through the last three points but the earliest points are not in agreement with this line. The reciprocal of the slope of the straight line gives a value of maximum possible recovery of 112 pct. The maximum possible recovery according to the first order rate plot is 78 pct. In Fig. 11 the first order rate plot again fits all of the points very well and passes through the origin. The second order rate plot shows wide deviation of the earliest point, indicating that the second order rate equation is not applicable. The reason for the fit of data to the second order rate equation during longer flotation times is that R, the cumulative percent recovery, changes slowly toward the end of the flotation operation, so that when t/R is plotted against time, one is, in effect plotting t against t and one would certainly expect a straight line. The author attempts to show that the second order rate equation is correct by citing evidence which shows that recovery is a function of initial concentration. This is a debatable point especially since, in the author's original presentation of this paper at the St. Louis

Jan 1, 1952

By A. B. Dyes

In the operation of a water-driven reservoir, a free gas saturation can he established by maintaining production rates fast enough to cause the reservoir pressure to decline below the bubble point. The benefit of such a procedure on the displacement efficiency of the oil by water is illustrated for two types of sandstone samples from one reservoir. Those rock samples showing the poorest recovery to water drive in the absence of a free gas saturation give the most improvement in the presence of a free gas saturation. Employing one type of reservoir fluid (low .shrinkage) the benefit of evolved gas on oil displacement is calculated at several reservoir pressures below the bubble point. This demonstrates the presence of air optimum pressure for water displace,rnent which is .several hundred pounds per .square inch below the bubble point. Displacement of oil at the optimum pressures results in the removal of 7 to I? per cent more oil than would be obtained by displacement at the bubble point pressure. In some instance. this magnitude of increase may be worthy of consideration in establishing the maximum efficient rate of production from many water-driven fields. INTRODUCTION For many years the belief that the use of gas could be combined with that of water to result in a better recovery operation than the use of either of these phases alone has been prevalent in the oil industry. This is evidenced by the several field trials which have employed the injection of gas and water in combination.1.2.v In most cases the small amount of any additional recovery, in combination with the limited knowledge available on the older reservoirs, has left uncertain the influence of gas on recovery in these earlier attempts to combine the use of gas with water. Research studies in recent years have demonstrated through laboratory. floods the magnitude of the benefit of the presence of gas on the displacement of oil from sandstones by water.5,6,7,8,9,10,11 In addition, studies of the distributions of the phases which are present during the displacement process have developed concepts concerning the mechanism by which this benefit is obtained."." It now remains for the engineer to incorporate these findings into the general technology of reservoir operations. It is the purpose of this paper to illustrate that the production of a water-driven reservoir at pressures below the bubble point is one such operation whereby improved oil displacement efficiency can be obtained as a result of gas evolution. The establishment of a gas saturation by evolution of dissolved gas was one of the techniques used by several investigators in the laboratory studies. The possibility of obtaining the benefit of gas evolution in water-driven reservoirs by producing at pressures less than the bubble point has 3150 been pointed out previously." The desirability of this operation has undoubtedly

Jan 1, 1955

By R. Y. Williams

IN the United States, fully 98 per cent. of the anthracite and bituminous coal tonnage obtained from underground operations is mined by the room-and-pillar system. Under this system, the total cost of the coal f. o. b. railroad cars contains as its greatest single item the money paid for "labor." Each labor dollar in an. average bituminous mine may be subdivided into 85 c. paid for work done inbye the gathering turnouts (including all work at the face), and 15 c. outbye that point (including all work in and under the tipple). In an average anthracite mine, the corresponding figures are 70 c. and 30 c., the larger breaker force accounting mainly for the difference between these and the bituminous figures. The next largest single item after "labor" is usually "supplies and power;" and a division of this item inbye and outbye the gathering turnouts shows somewhat the same relative proportions as has been noted under the case of "labor". During the past 10 years, the chief advances made in the coal industry have been to obtain economies through complete mechanization covering that portion of the work which lies outbye the gathering turnouts. These results have been accomplished by applying scientific principles to railroad yard layout, to cleaning and sizing machinery, to dumping facilities, to roller-bearing haulage equipment, and to heavy-rail, well-ballasted trackage. But these improvements, while gratifying in their resulting economies, apply only to 15 to 30 per cent. of the important cost items. Obviously, then, the big problem before the engineers of the coal industry today has to do with the methods of mining and the layout inbye the gathering turnouts. Four years ago, Weston Dodson & Co., Inc., determined to have an exhaustive study made of the conditions which must be met in order to gain complete face mechanization, and in order that such a mining layout would be based on, correct underlying principles. The result of that study, which was made by the writer, led to the adoption of a method of longwall mining wherein the. roof is worked on the caving system and is supported as an overhang along the face by steel jacks.

Jan 1, 1928

In the past few years the hydraulic aspects of rotary drilling have received considerable attention. It is generally recognized that accurate prediction of circulating pressures is desirable, particularly in those areas where a delicate pressure balance is necessary to prevent both blowouts and lost circulation. For calculation purposes the standard hydraulic equations for the pipeline flow of Newtonian fluids have been altered to facilitate similar calculations for non-Newtonian or plastic fluids.'.' This latter classification includes most colloidal types of drilling muds. Two properties: plastic viscosity, un, and Bingharn yield value, Y,, are commonly used to define the flow characteristics of a plastic fluid. These are commonly obtained with multispeed viscosimeters such as the Fann V-G meter.3 Normally these measurements are obtained at some surface temperature, and are not corrected to circulating temperatures for calculation purposes. This may result in considerable error, particularly in the laminar flow calculations which comnlonly apply to the drill pipe-borehole annulus. The purpose of this study was to investigate the effect of temperature on the flow properties of some water-base muds. A laboratory model Fann V-G meter was used for measurement of viscosities, yield values and gel strengths. An aluminum water jacket with O-ring seals was machined to fit around the mud cup of the Fann meter. All mud samples were prepared by thorough mixing in a Hobart mixer. Viscosity and gel strength measurements were made with the Fann meter using standard procedures. Flow properties of muds were studied at 80, 120, 160 and 180°F. The compositions of the test samples are given in Table 1. The typical effect of temperature on the flow properties of these drilling muds is illustrated by Fig. 1. It was found that plastic viscosity and apparent viscosity decreased with an increase of temperature. However, the curves were not linear, and did not appear to follow any definite trends or patterns. Yield point data showed much more scattering.' Since a usable method for predicting drilling mud flow behavior with temperature was desired, an attempt was made to find a simple relationship between these variables. The basic approach used by Havenaars for predicting the same effect on turbulent viscosity resulted in Fig. 2, which shows that

By E. P. Pfleider, O. Rellensmann

For many years mine surveyors and exploration engineers have sought an accurate means of transferring meridian underground by using the gyro-compass. These efforts have generally failed, either because they were inaccurate or because the size and cost of the unit were prohibitive. During the past ten years, however, great strides have been made. Autonetics in California has developed a comparatively light-weight (100-lb) gyro-theodolite, and the Institute for Mine Surveying at Clausthal Mining Academy in Germany has developed an instrument that is accurate to within 20" to 30" of arc. Concurrently, Minneapolis-Honeywell has produced an astounding gyro, the size of a salt shaker, that weighs less than 0.5 lb and compares favorably in performance with the 50-lb gyros of conventional design. This unit, designed for missile guidance, should be adaptable for surveying small boreholes. Given the proper interest and approach from the engineering fraternity, excellent gyrocompasses could probably be available for accurate underground survey work at nominal cost within the next three years. Principles of the Gyro-Compass: The gyrocompass, used for 50 years as a navigational instrument in ships and aircraft, senses the turning axis of the earth and points out true polar north. It does this by employing the earth's rotation, the force of gravity, and the precession characteristics of a gyro. For further details the reader is referred to several excellent publications'"3 covering the principles and application of the gyroscope. The heart of the gyro-compass is the gyroscope, or rapidly spinning wheel, which rigidly maintains its angular orientation in inertial space. Free gyros employ universal joints to allow the wheel axle to maintain its rigid spatial orientation independent of base motion disturbances. Free gyros are independent of the earth's turning and are not north-seeking. Only as they might be initially oriented parallel to the earth's turning axis could any north indication be obtained. In practice, the free gyro tends to drift off its set position and lose its accuracy. The Sperry-Sun Well Surveying Co. instrument (5M in O. D.) is of this free gyro type. It is counterbalanced, however, against the rotational effects of the earth, so that orientation of the spinning axis will be maintained throughout the survey.

Jan 1, 1960

By Wallace E. Pratt

IRon-oRe deposits in the Philippine Islands became the subject of official record as early as 1664. Undoubtedly iron ore was known and recognized by the Filipinos long before the earliest Spanish records. It is even possible that the Filipino practice of smelting iron ore is, like the native copper smelting, older than the Spanish conquest of the islands. The first records have to do with the magnetite-hematite ores near the towns of Santa Inez and Bosoboso in Rizal Province, from 15 to 20 miles east of Manila. The magnetite-hematite ores of Bulacan were exploited in 1783. Similar ores near the town of Mambulao in Camarines Province yielded a number of specimens to be exhibited in Spain in 1834. With the exception, then, of the lateritic iron ores on the eastern coast of northern Surigao, the true nature of which was not recognized until 1914, the important iron-ore deposits of the Philippines had all been discovered before the islands came under the dominion of the United States. Indeed, in the Spanish documents relating to the history of iron mining are statements which, if their accuracy be not questioned, leave us in the Philippines today with much less iron ore than the Spaniards found. To quote, for example, a report submitted to the Superior Government in Spain in 1835 by one of its emissaries, Don Lorenzo Calvo: "The Philippine Islands, most excellent Sir, possess iron and exhibit it in nearly every known mineralogical combination, and in such abundance that the cordillera of the island of Luzon, from Montufar Point in San Bernardino Straits to Cape Bojeador, is composed of no other mineral than iron, its ranges, of the third order, being in content and structure totally iron of the best quality, the more valuable in that its combinations are such as to facilitate its fusion and to render its redaction to metal simple." Today, however, it is recognized that the iron-ore deposits in the Eastern Cordillera of Luzon constitute, not a continuous belt, but a series of widely separated deposits, including a half dozen orebodies within a distance of 10 miles in Bulacan Province, a single outcrop at Santa Inez, Rizal Province, farther south, and three deposits around

Jan 1, 1916

By Albert Hill Fay

In giving a sketch of the geology and mining of the tin-deposits of Cape Prince of Wales, a short description of the geographic and climatic conditions may be of special interest on account of this being a part of the world of which very little is known, even by the reading public. As shown in Fig. 1, the location of the Cape is lat. N 65° 35' and long. W. 168o. It is bounded on the north by the Arctic ocean ; on the west by Bering strait and on the south by Bering sea. It is the Westernmost point of the mainland of North America, and to the west, across the strait, one can see East Cape, Siberia, which consists of a rugged, steep coast of granite cliffs. The climatic conditions arc of interest because of the part they have had in the surface geology, and also because they affect mining from an economic standpoint. In connection with the climate and geography, it does not seem out of place here to quote a few lines from the prologue of The Wandering Jew, written by Eugene Sue, under the caption " The Land's End of Two Worlds." "The Arctic Ocean encircles with a belt of eternal ice, the desert confines of Siberia and North America—the uttermost limits of the Old and New World, separated by the narrow channel known as Bering's Straits. " To the north, this desert is bounded by a ragged const, bristling with huge black rocks. At the base of this Titanic mass lies enchained the petrified ocean (Bering sea) whose spell-bound waves appear fixed as vast ranges of ice mountains, their blue peaks fading away in the far-off frost-smoke, or snow-vapor. " Between the twin peak* of East Cape, the termination of Siberia, the sullen sea is Been to drive tall icebergs across a stream of dead green. There lies Bering's Strait. Opposite, and towering over the channel, rise the granite masses of Cape Prince of Wales, the headland of North America. "These lonely latitudes do not belong to the habitable world."

Jan 1, 1908

By Frank C. Canney

The word "other" in paragraph 4, line 11, column 1, page 205, should read "over;" the correct version of reason 2, this paragraph, is: 'L. . . 2) to evaluate the usefulness of certain geo-chemical techniques, V. C. Kennedy and S. W. Hobbs of the USGS had already studied the distribution of copper, lead, and zinc in the soils (both in background areas and over veins) and in the water and plants, providing a criterion for measuring the magnitude and effect of soil contamination; ...9 On page 206, in the top left hand corner of Fig. 1 (in the area bounded by 47°35' and 116°10), the reference to Fig. 3 is incorrect. The area of Pine Creek, South Fork Coeur d'Alene River, and portion of Big Creek (the area which includes, from left to right, Kingston, Pinehurst, Smelterville, and Kellogg) should be identified as that of Fig. 2A. The headings for columns 1, 3, and 4, Tables I and 11, page 209, column 2, were reversed when the paper was printed. The corrected tables are:

Jan 1, 1961

In an address delivered at Atlantic City, N. T., Dec. 5, 1918, M. L. Requa, General Director, Oil Division of the United States Fuel Administration, said: We face a new era with all its uncertainties. We have arrived at the period of reconstruction and are face to face with the problems concerning which we have so often speculated during the past four years. In all this reconstruction work the United States must bear an important part. We are looked upon to lead the way, to blaze the trail and our actions will have a profound influence upon the rest of the world. If we are to succeed, even in part, we must not be ashamed to practise economy; we must not despise the clay of small things; the little savings; we must have the closest cooperation between Government and industry. Just as truly do we need civic awakening. All that we have ever fought for, the liberty of the world, is comprehended in the ballot; and yet how lightly we have held this great privilege! We need, if we are to reap in full the benefits of the past 18 mo., an awakened civic consciousness; a jealous guarding of government; a resolution that we will, each and all, perform to the full the duties imposed upon us by Democracy; that we will perform more completely the obligations resting upon us as citizens. During the war, industry, through sane cooperation and intelligent effort, has accomplished results possible of attainment in no other way. Government and industry have worked hand in hand and pointed the way o to future activities which, if realized, can but be most highly beneficial to all. If Government and industry are to fulfill their respective duties satisfactorily, it is obvious that there should be complete mutual confidence. Industry must not attempt to "put something over"-and Government must treat with industry upon the high plane that has characterized the public utterances of the President during the war. The individual who cannot conform to these high ideals should have no place in industry, and equally no place in Government. If the dignified and broad princi-

Jan 2, 1919

By Fred P. Peters

At first glance this paper may seem unique among those comprising this symposium on designing for powder metallurgy, since it is evidently concerned with everything but Powder metallurgy. This paradox mill be at once resolved, however, when the real Purpose of the symposium meeting is understood—to present factually and objectively the things that can and cannot he done with powder-metallurgy methods, and especially to set forth with brutal frankness the limitations of Powder metallurgy, so that costly over-enthusiasm and misapplication may be prevented. Since much of powder metallurgy's future development (and many of its present disappointments) has been in competition with other and long-established methods of fabricating parts, it is easy to see that its true competitive possibilities in any given case cannot be accurately appraised without rudimentary knowledge of what the competition can do. This paper, therefore, presents a few reminders of things you all know—a background to be kept in mind as you examine the data on each of their specialties given by the authors of the papers that follow. From the standpoint of the design engineer powder metallurgy is often in Competition with one or more of the following: sand casting, die casting, permanent-mold casting, precision investment casting, ma- chined bar stock, screw-machine parts, cold-heading, drop-forging, and stamping and drawing. We will here briefly discuss each of these individually, and set forth so, rough (and therefore dangerous) generalizations about its competitive position, especially with respect to powder metallurgy. Sand Casting Sand-casting of small parts is sometimes an inexpensive method of manufacture, for its raw-material costs (i,e., for gray iron) are the lowest of the various methods and it involves the use of no tools and dies of jewelry quality. its design flexibility— that is, the ability to make complicated, cored and undercut parts in one piece—is about the highest of the competing processes and in this respect it can do many things that are impossible by powder metallurgy. For small castings its production rates may be higher, by using multi-impression molds, than can be achieved with parts of the same size by powder metallurgy. But its labor charges for melting, pouring, patternmaking and molding are comparatively high and the waste it entails in gates and risers is always considerable. Tolerances of sand castings are wide (+1/6 to 1/32 in- per in.) and where precision approaching that of powder metallurgy is required sand castings must be machined to final size, thus increasing their cost. Steel sand castings are more expensive and less precise than iron, and nonferrous the most costly of all.

Jan 1, 1945

By S. H. Cathcart

Price, production and drilling operations exceeded any year since 1930. A top price for crude of $2.55 was maintained from May 1 to November 6 and increased activity about coincides with that period. The average crude price for the year was: Bradford, $2.46; Kane-Butler, $2.34; Southwest Pennsylvania, $2.13. Production for the year exceeded 15 million barrels, an increase of about 2 million barrels over 1933. That this increase was more than justified by market demand is indicated by a reduction of 892,000 bbl. in stocks for the year. Two classes of data appear on Table 1, which are differentiated by footnote references. Where possible the .figures were obtained from individuals and companies that, from long acquaintance and varied contacts, are most capable of supplying an estimate where an estimate is necessary. The remaining data represent a rather careful compilation from all available published records (see p. 378). Drilling operations and production as summarized by the Oil City Derrick are as shown on Table 2.

Jan 1, 1935

By Earl Hunner

IT is common knowledge that the iron orebodies of the Mesabi range lie nearly horizontal and are of trough or blanket-like types. These orebodies are from a few feet to several hundred feet thick and vary from a few acres in extent to the size of the largest one, at Hibbing, Minn., which is over 1 mile wide and 3 miles long. They are covered with sand, boulder and clay overburden and occasionally, shallow depths of ledge material, varying in total depth from about 20 to 200 ft. Large areas are not capped with overlying ledge material; the top of the ore lies directly underneath the surface material. Because of the comparatively great tonnage of ore, open-pit mining has made tremendous strides since the first open-pit ore was shipped from this range by the Merritt brothers, from the Mountain iron mine in October, 1892, and along with the great development of open-pit mining on the Mesabi range has gone a tremendous change in the character of equipment used.

Jan 1, 1930

A mine in the mountains of southeastern British Columbia is fast earning a reputation as the safest metal mining operation of all time. Already officially proclaimed as the safest mine in Canada, the H.B. mine of The Consolidated Mining and Smelting Co. of Canada (Cominco) continues to advance its safety performance far in the lead of average accident frequencies in mines across the country. Official recognition came its way again this spring when the Cominco mine was awarded the John T. Ryan trophy for the fourth time in the last five years. This award is emblematic of top national safety performance of a metal mining operation. The H.B. mine is its only four-time winner. The Ryan award is based on a frequency of accidents involving lost time of more than six days. In each of the years that the H.B. has won the award-1958, 1959, 1961 and 1962-its frequency was zero, with no accidents involving a time loss of more. than six days

Jan 12, 1963

By Rupert Spivey

Kennecott Copper's Chino mine is one of the oldest copper mines in the United States, having been operated by the Spaniards as early as 1800. At that time haulage methods were indeed primitive. Indians brought the ore up on "chicken ladders" in leather buckets. It was then melted into crude bars and hauled to Chihuahua by mule train. There are still remnants of the old trails near the present pit where the mule hooves cut grooves in solid rock. The mines were worked as underground operations off' and on until open-pit mining was started in 1910 by John Sully and Daniel C. Jackling. Since that time many haulage methods have been used: mule carts, steam and electric trains and finally large haulage trucks, now believed to be the best method for this mine. The general shape of the pit is oval with dimensions of 1% miles by 1% miles. Working benches are 50 ft high, with the bottom bench at 5750 ft and the top at 6450 ft above sea level.

Jan 1, 1964

By Glenn C. Waterman

The use of stream sediment and soil sampling as an aid in exploration has markedly increased in recent years as more and more attention has been directed to areas that are generally geologically favorable for mineralization but show little outcrop. Numerous ore deposits and many hundreds of mineral deposits that have no surface exposure have been found associated with anomalous geochemical patterns. Sophisticated techniques have been developed to "wring out" of geochemical data subtle information that is pertinent in defining areas of exploration interest. Variations in metal patterns in soils and sediments as they are affected by pH, Eh, weather, topography, etc., are pretty well known. Field studies have determined the variations and controls of metal ion distribution in the several soil horizons and the contributions to metal concentrations made by different types of vegetation. Less well known is how to interpret geochemical data since thickness of soils over bedrock varies in an unknown fashion and, particularly, where glacial debris of unknown thickness is piled on top of soils or scoured bedrock.

Jan 7, 1975

By J. G. Bradley

On February 1, 1971, United States Steel Corporation, Lorain Works began operation of its first BOP facility equipped with a partial combustion gas cleaning system.- This shop consists of two 220 ton vessels. Figure I schematically describes this partial combustion gas cleaning system and highlights the necessary features for it-s safe and efficient operation. Waste gases are drawn into the membrane hood by a 2250 H.P. induced draft fan and are first quenched by the six inch bull nozzle at the top of the hood. Larger solid particles are separated from the gas in the quencher venturi and final scrubbing takes place in the P-A high energy venturi scrubber before the cleaned waste gas is burned in the flare stack. Scrubbing water is routed through a cyclone separator and then cycled into one of two 100' diameter thickeners. Underflow sludge which averages 20% solids is dewatered by 100 H.P. centrifuges. The clear overflow from the thickeners is recycled first to the P-A venturi and then to the quencher before returning to the thickeners.

Jan 1, 1972

Canadian owned Lake are carriers will be used again this year in an attempt to make up the deficit caused by the two months steel-strike. Buffalo mills need between 5 million and 6 million tons of ore before the Lakes navigation season ends. Mutual Security Program aid will help reactivate Austria's largest iron ore mine. The Erzberg development is one of the moat important in Europe. MSA announced approval of $500,000 in supplemental financing of equipment. Following the war, the Russians stripped the Erzberg and Radmar deposits of equipment. The he Carborundum Corp. is going to build a $2.44 million plant at Akron, NO.. TOP near Niagara Falls for production of rare metals used by the Atomic Energy Commission. A subsidiary, the Carborundum Metals Co., Inc.,, will produce zirconium, hafnium sponge metals. The pyrochlore rich Sukulu Hills in Eastern Uganda will be mined under a pool arrangement including Tinto Mines, Monsanto Chemicals and Frobisher Mines. The combine will be known as the Uganda Development Corp., Pyrochlore is used in the manufacture of heat-resisting. alloys for Jet engines.

Jan 1, 1952

FROM north to south activity is picking up through- out the Labrador Trough-already shown to be one of the world's great iron ore provinces. Center of current activity and interest lies in the mid-southern part of the trough as drills, equipment, and . . . money start to pour into the area near Mt. Wright and Wabush Lake. First major announcement in the area came early this spring when J&L and CCI outlined an estimated billion-ton deposit for "future" operations. Later impetus came from rumored railway for US Steel's Quebec Cartier projects in the Mt. Reed area slightly to the south. As this issue went to press US Steel's request for bids on railway and hydroelectric construction, plus IOCC's decision to step up the time- table on its program in the Wabush Lake area east of Mt. Wright, triggered a flurry of other announcements involving many of the top U. S. and Canadian iron ore firms. Do not look for most of these place names in the average atlas . . . they aren't there yet, but they soon will be.

Jan 6, 1958

By Walter Scott

THE removal of lead by fire refining methods from copper of electrolytic quality is growing in importance. Particularly is this true of the refining of secondary copper and copper cathodes obtained from electrolytic cells where lead is used as the anode material, as in the electrolysis of ore-leaching solutions and foul electrolyte. When investigating the removal of small amounts of lead from molten copper in a reverberatory furnace during the refining of secondary copper of otherwise electrolytic copper quality,1 it was found necessary first to FIG. 1.-SAMPLING DEVICE. know something about the distribution of the lead throughout the bath. The authors believe that it is not generally known how small amounts of lead as an impurity are distributed in a molten copper bath; that is, whether the lead is concentrated at the bottom or at the top, or whether it occurs more or less uniformly throughout the bath. The data contained in this report may help, therefore, in the development of a satis-factory fire refining method for the removal of this obstinate element from a molten copper bath.

Jan 1, 1930

By M. L. Fuller

IN connection with an investigation in this laboratory on the high-zinc side of the copper-zinc system, it was observed that well developed segre-gate structures of the Widmanstätten type were formed when a secondary phase precipitated from the solid solution of copper in zinc. This paper presents an analysis of the crystallographic relationship between the segregate and the solid solution matrix. The data to be presented are an interesting addition to the literature on segregate structures in that the plane of segregation is one of the less densely populated planes. In agreement with the generalization of C. H. Mathewson and D. W. Smith1 the plane of segregation in the matrix con-tains the direction of closest atomic packing of the lattice. Furthermore, the matrix and the segregate are both hexagonal close-packed, which has not been reported hitherto in the literature.2 The increasing com-mercial importance of zinc alloys containing copper makes this funda-mental study of value to the metallography of zinc alloys.

Jan 1, 1933