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By Francis A. Thomson

DO the curricula of our mineral technology schools prepare their graduates to meet properly the full range of their responsibilities in after life? An unequivocal "no" could be returned to this question, because training and experience in professional work are quite as important as adequate college preparation. Furthermore, a had curriculum with a splendid corps of men doing the teaching and a competent body of students doing the learning will produce a better result than an ideal curriculum in the hands of unqualified teachers and poorly prepared students.

Jan 1, 1937

By J. K. Buehler

With the rapid acceleration of the cost of shovel dippers and major standard shovel clipper rebuild components, maintenance management at Kennecott Copper Corp.'s Bingham Canyon mine initiated a dipper maintenance and rebuild program. The program focused on extending the service life of the shovel dipper, reducing field labor in maintaining dippers, and lowering shovel dipper rebuild costs. While comprehensive evaluation of the program is still underway, preliminary benefits of the program indicate: •Reduced field ,gelding for shovel dipper field maintenance, •Fewer dipper rebuild units entering the shop, and •Reduced dipper rebuild costs per unit.

Jan 1, 1979

By S. H. Chauvenet

Jan 1, 1882

By David T. Day

In the summer of 1898, a demand suddenly arose for commercial quantities of the element osmium. At least half a ton was wanted for the manufacture of a new incandescent light. This led the writer to examine localities where platinum had been reported, in order to determine whether osmiridium mas contained in the crude platinum. With the co-operation of the concern most interested, the Welsbach Light Company, and in company with its President, Col. William E. Barrows, I visited most of the leading American localities where platinum has been obtained. I also wrote to every available placer-mine in the West for samples of the heaviest sands, in order to test them for platinum. The results of this inquiry are given in the present paper. Distribution. The notices of the occurrence of platinum in this country given in scientific journals include two interesting observa tions in the East. One concerns a nugget described by Peter Collier of Washington, D. C.,* and said to have been found on land adjacent to the village of Plattsburgh, N. Y., which weighed 104.4 grammes, and contained sufficient chromite to reduce the specific gravity from 17.35 for the heaviest portion to

Jan 1, 1901

By Donald H. McLaughlin

ZEST in the search for new supplies of metallic ores and petroleum is difficult to maintain with stocks of raw materials accumulating and with over- production rightly or wrongly blamed for most of our industrial troubles. Enthusiasm over new methods of prospecting has consequently diminished and exploration programs in many fields have been drastically cur- tailed. Very naturally the effects have been felt with particular keeness in highly specialized phases of the work, such as geophysical prospecting, for the feverish scramble for new areas in which to drill beneath magnetic or electrical anomalies has abated, and there is even a lull in the firing in the battle over salt domes on the Gulf Coast. It is unquestionably an unhappy time for many of the organizations dependent on this work, but in certain respects the situation may be beneficial in correcting unsound practices that .have grown up through the necessity for haste and for quick decisions. With the restriction of the field to the more competent workers by the harsh rule of survival of the fittest, a general improvement, not only in technique but in business methods, can be expected which may go far in restoring public confidence. Geophysical prospecting in the short period that it has been utilized in North America, has suffered severely both from over-popularity and from excessive abuse. The former evil now

Jan 1, 1931

By M. Baeyertz

SINCE 1915 many papers and books have covered industrial applications of X-rays from various angles. Two of the more recent are a paper by Fink and Archer1, which describes in detail the technique of radiography, and a paper by Clark2, which embraces the whole field of X-ray metallography. This paper, therefore, is confined to work of the X-ray Laboratory of the Western Electric Co., which naturally divides into two categories: radiography and diffraction patterns of various types.

Jan 1, 1930

By AIME AIME

WHETHER by the Mohawk Trail, Sound steamer, air plane, railroad or any other route or mode of locomotion, all roads will lead to Boston the week of National Metal Congress, Sept. 21-25. The Institute of Metals and Iron and Steel divisions of the Institute are then to meet jointly at the Hotel Statler, and the American Society for Steel Treating, the American Welding Society, the Society of Automotive Engineers and the Iron and Steel Division of the American Society of Mechanical Engineers present carefully planned programs at their respective sessions. The National Metal Exposition will be held on Commonwealth Pier.

Jan 1, 1931

By Shiou-Chuan Sun

THE fact that coals of different ranks and even of the same rank differ greatly in their amenability to froth flotation is well known. In recognition of the need for an explanation of this phenomenon, two hypotheses have been suggested. Wilkins1 reported that the floatability of coals increased with an increase of the carbon content or rank. This postulate is handicapped by the fact that bituminous coals that possess moderate carbon contents are actually more floatable than anthracite coals that have high carbon contents, as shown in columns 6 and 9 of Table I. Taggart and his associates' implied that the difference of floatability between bituminous and anthracite coal was caused by the variation of carbon-hydrogen ratio. This is not applicable to the relative floatability of other coals and carbons. For example, column 11 of Table I shows that the carbon-hydrogen ratios of low-floating lignitic coal and non-floating animal charcoal are not only smaller than the moderate-floating anthracite coal, but are also similar to the high-floating bituminous coal. Furthermore, according to this hypothesis, high temperature coke-A (464), Ceylon graphite (1238), and lamp-black (357), all possessing extremely high carbon-hydrogen ratios, should be less floatable than other substances having much lower carbon- hydrogen ratios such as high volatile-B bituminous coal (11.9 to 22), anthracite coal (35.7 to 60.5), lignitic coal (15.6 to 33.6), and charcoal (13 to 26.2). However the former group is actually more floatable than the latter group.

Jan 1, 1954

CHICAGO SECTION CHAS. H. MACDOWELL, Chairman, LUTHER V. RICE, Vice-Chairman, HENRY W. NICHOLS, Secretary-Treasurer, GEO. P. HULST, ALEX. K. HAMILTON, FREDERICK T. SNYDER, HENRY P. HOWLAND. The Field Meeting of the Chicago Section proved to be the most enjoyable meeting ever held by the Section. It took the form of a visit to the Northern Indiana Industrial District where the day was spent inspecting metallurgical plants in Indiana Harbor and East Chicago and in amusement at the Hammond Country Club. The weather was perfect and about 50 members and ladies attended the meeting. An inspection of the plant of the Inland Steel Co. occupied the morning. The plant was decorated in honor of the occasion and the company provided attractive souvenirs. It was noticed here that many of the ladies displayed an interest in the inspection and an understanding of the processes that would not have shamed professional metallurgists. While the members of the Section seemed to be most interested in the by-product coke ovens and the by-product recovery plant, the ladies enjoyed especially watching the snake-like antics of the red-hot rods in the wire mill. Leaving the steel plant, the Section enjoyed a ride through the district by automobile and arrived at the Hammond Country Club in time for lunch. In the afternoon some of the members inspected the plant of the International Lead Refining Co., at East Chicago, while the rest spent the time at the Country Club in golf, tennis, trap shooting, bridge and other amusements. During the dinner at the Hammond Country Club an informally organized male quartette led the singing in real college boy style. In the evening, E. E. Billow talked on the use of oil burners in metallurgical furnaces, Mr. MacDowell told of the present status of the Potash Industry and the Secretary told of some of the happenings at the Arizona Meeting. HENRY W. NICHOLS, Secretary.

Jan 12, 1916

By Alwyn Birchmore Cox, Ian William Wark

In defending the chemical theory of flotation, Taggart, del Giudice and Ziehl have criticized1 the views of those who prefer to attribute the effects of certain flotation agents to adsorption. Perhaps with some justification, they describe the latter term as the "haven of refuge of writers lost in a morass of shaky experiment and muddy thinking." We prefer to regard it, however, as a haven of refuge for writers who seek a conventional term to describe the formation of films of flotation reagents on solid surfaces, because in many cases it is not yet possible to specify the forces that hold them there. Originally, as Taggart and his associates state, adsorption connoted a concentration difference and nothing more. In recent years, workers in the field of surface chemistry have tacitly added other meanings, and they now speak of orientated adsorption of unimolecular films on a solid sub-strate, of chemi-adsorption, and of exchange adsorption. Thus the term adsorption may connote simply the Gibbs layer of excess concentration at the surface of a solution, or a unimolecular film at the surface of a solid. Perhaps this has led to the misunderstanding of Taggart, del Giudice and Ziehl concerning the relationship between surface tension and adsorption at solid surfaces. The change in "surface tension" accompanying adsorption at a liquid surface can be used as a measure of the adsorption, and the Gibbs equation as quoted by these authors correlates these two conceptions. But, to correlate two conceptions docs not necessarily imply an attempt to explain either, although sometimes such an "explanation" is carelessly inferred. Use of "surface energy per unit area" instead of the numerically equal but more difficult and less definite conception of "surface tension per unit length " would lessen many of the present difficulties. (Compare with Adam.2) At interfaces involving a solid phase, neither '" surface tension " nor " interfacial tension "can have any meaning, but the conception "interfacial energy per unit area" call be understood by anyone who is familiar with the concept of free energy. While it is true that surface energy cannot be directly measured at a solid surface,

Jan 1, 1939

By Ian William Wark, Alwyn Birchmore Cox

In defending the chemical theory of flotation, Taggart, del Giudice and Ziehl have criticized1 the views of those who prefer to attribute the effects of certain flotation agents to adsorption. Perhaps with some justification, they describe the latter term as the "haven of refuge of writers lost in a morass of shaky experiment and muddy thinking." We prefer to regard it, however, as a haven of refuge for writers who seek a conventional term to describe the formation of films of flotation reagents on solid surfaces, because in many cases it is not yet possible to specify the forces that hold them there. Originally, as Taggart and his associates state, adsorption connoted a concentration difference and nothing more. In recent years, workers in the field of surface chemistry have tacitly added other meanings, and they now speak of orientated adsorption of unimolecular films on a solid sub-strate, of chemi-adsorption, and of exchange adsorption. Thus the term adsorption may connote simply the Gibbs layer of excess concentration at the surface of a solution, or a unimolecular film at the surface of a solid. Perhaps this has led to the misunderstanding of Taggart, del Giudice and Ziehl concerning the relationship between surface tension and adsorption at solid surfaces. The change in "surface tension" accompanying adsorption at a liquid surface can be used as a measure of the adsorption, and the Gibbs equation as quoted by these authors correlates these two conceptions. But, to correlate two conceptions docs not necessarily imply an attempt to explain either, although sometimes such an "explanation" is carelessly inferred. Use of "surface energy per unit area" instead of the numerically equal but more difficult and less definite conception of "surface tension per unit length " would lessen many of the present difficulties. (Compare with Adam.2) At interfaces involving a solid phase, neither '" surface tension " nor " interfacial tension "can have any meaning, but the conception "interfacial energy per unit area" call be understood by anyone who is familiar with the concept of free energy. While it is true that surface energy cannot be directly measured at a solid surface,

Jan 1, 1939

By R. E. Zimmerman, Michael Sokaski, E. R. Palowitch, M. R. Geer, H. F. Yancey, W. Deurbrouck, S. C. Sun

PART 1: DENSE MEDIUM SEPARATION by M. SOKASKI, M. R. GEER and H. F. YANCEY INTRODUCTION In the early days of coarse-coal treatment by the dense-medium process in Europe, loess was one of the materials used for medium solids. Newly developed cyclones were used to reclaim and thicken :he loess suspension. On occasion, when the cyclone thickener at the Maurits mine in the Netherlands plugged, the overflow was found to be filled with clean coal free of impurity. From this observation stemmed the concept of the cyclone as a cleaning device. Development took place during World War 11 in the laboratory of the Dutch State Mines under the direction of M. G. Driessen. A 15-ton-per-hour pilot plant was in operation in the laboratory by 1945, when, in September, Driessen made the first public disclosure of the process in a paper presented to the Institute of Fuel in London. In April 1945,2 operation of this pilot plant was observed by one of the authors, who was so impressed with the potential of the cyclone process that, on his return to the United States, a research program on the cyclone was started by the Bureau of Mines immediately. This work led to an AIME paper in 1946 in which the first details of cyclone operation on American coals was made available. Commercial adoption of the cyclone proceeded in Europe, initially in the Netherlands, Germany, and France. In the United States, where coal is less costly and most of the coals are so easy to clean they respond well to simpler cleaning systems, the first cyclone plant was not built until 1961.3 As of the spring of 1967, a total of 31 commercial cy- clone plants had been installed or were under construction in the United States; this does not include eight Dynawhirlpool plants. The capacity of the cyclone plants ranges from 50 to 1300 tons per hour and totals 6600. THEORY Before discussing the theory of a dense medium cyclone, a brief description may be helpful to some readers who are not familiar with its basic operation. In a typical dense-medium cyclone, illustrated in figure 10-1, the mixture of medium and raw coal enters tangentially near the top of the cylindrical section, thus forming a strong vertical flow. The refuse moves along the wall of the cyclone and is discharged through the under- flow orifice. The washed coal moves toward the longitudinal axis of the cyclone and passes through the vortex finder to the overflow chamber.

Jan 1, 1968

By A. W. Gauger

Coal as mined contains varying quantities of inorganic components (mineral matter) which, on combustion, produce the residue known as ash. It has long been realized that the weight of this residue does not equal the weight of the mineral matter originally in the coal, because of the chemical changes that take place during the ashing process. Moreover, the ordinary ash analysis presents the ash as a mixture of oxides with little or no clue to the identity of the mineral species originally present in the coal. It is only for pyritic sulfur that an attempt is made to determine a mineral component. So far as the authors are aware, there are practically no experimental data in the literature as to the percentages of the different mineral species present in coal. The oft-quoted table of Marson and Cobb1 cannot rightly be considered as data, since the authors merely state that the table "shows the probable forms in which these ash constituents exist in coal." In view of the attempts to calculate analyses and determinations of the calorific equivalent of coal to the mineral-matter-free basis, as well as the importance of the mineral species in clinkering, combustion and coking, it seems strange that so few data are available on this phase of coal technology. For example, numerous empirical corrections for use in the scientific classification of coal have been suggested to compensate for the losses from the mineral matter during ignition of the coal to ash. These include multiplication of the ash percentage by various factors such as l 1/10 and 156, the use of the Parr unit coal formula (1.08 A + 22/40 S, where S = total sulfur) as well as certain modifications of the Parr formula that attempt to correct for the organic sulfur present in the coal. Although many experiments have been made to determine the loss on ignition of the clays associated with the coal measures and correction

Jan 1, 1934

By E. L. Tucker

PREVIOUS investigations of E. L. Tucker and R. E. Head' related in particular to the effect of cyanogen compounds on galena, sphalerite, and pyrite, and their behavior in the presence of such com- pounds. The present contribution deals with the float- ability of the copper minerals and of pyrite. All experiments were performed on minus 200-mesh material, the method of preparation being the same as that described in the previous article. Flotation tests were made in a small mechanically agitated machine of 50-g. capacity designed in this laboratory by Gates and Jacobsen." General Naval Stores pine oil No. 5 and potassium xanthate were used in constant amount in all of the experiments; these agents were selected because of their present wide use in the flotation of copper minerals. Lime additions were varied to secure four 'final hydrogen ion concentrations, namely, neutral, 0.0005 per cent CaO, 0.003 per cent CaO, and 0.02 per cent CaO. The variation in lime addition was introduced to include the range of alkalinities employed in actual flotation practice.

Jan 1, 1926

By J. R. Craig, T. N. Solberg, M. A. Linden

The central and southern Appalachian Mountains were the major sources of domestically produced gold throughout the first half of the 19th century and continue to yield gold today. Small amounts of gold were probably extracted by the Indians and the Spaniards but the first documented report of gold in the region was made by Thomas Jefferson who found, in the Rappahannock River of Virginia in 1782, a 1.8 kg (4 lb) lump of gold ore that yielded 26 g (0.85 oz). Gold was subsequently discovered in North Carolina between 1793 and 1799, in Virginia in 1806, in South Carolina in 1827, in Georgia in 1829, and in Alabama about 1830 (Becker, 1894-5; Pardee and Park, 1948). Production climbed to more than 933 kg/a (30,000 oz per year) between 1830 and 1852, but dropped sharply after the California gold rush in 1849 as experienced miners moved west in search of bigger and easier stakes. The Civil War briefly halted gold mining in the Appalachians, but production rose to an average of about 249 kg/a (8,000 oz per year) from 1865 until 1878 and to about 404 kg/a (13,000 oz per year) from 1881 until 1915 when it again fell to near nil (Pardee and Park, 1948). Minor resurgences occurred in the 1930s and 1940s. Although there has been no reported production in recent years, it is likely that "weekend panners" still remove hundreds of ounces from streams annually. The total reported production for the area through 1959 is more than 77 t (2.5 million oz). This paper reports some initial findings of a long-term project designed to investigate the mineralogy, chemistry, mode of occurrence, and petrology of gold occurrences in the Appalachians. The goal of the initial phase was to determine the compositional range of gold in the Appalachians as a step toward deciding if sufficient variations were present to allow the definition of "compositional signatures." The very few published data on gold fineness in the Appalachians are based on assays that commonly include gold and silver from several mineral species. Analyses in the present study were performed on individual grains of electrum using a spot size of 10 µm x 10 µm to 100 µm X 100 µm (394 X 394 micro in. to 3,940 X 3,940 micro in.), and thus reveal the true composition of the principal precious metal-bearing phase.

Jan 1, 1984

By Henry Schaefer

Solution by electric analogy of performance problems of reservoirs containing oil and gas has heretofore depended upon a process of successive approximations based on material-balance calculations, because of variation in fluid compressibility. By the addition or subtraction of electric condenser capacity, the analogy network can be adjusted automatically for changing compressibility due to evolution of gas in the reservoir. The addition of a condenser is accomplished by an electronic circuit, which is described; subtracting a condenser is done by merely opening the electrical circuit by means of a relay. Introduction V. Paschkis and H. D. Baker1 first developed in this country a method of applying the analogy of flow of electric current in noninductive circuits to solution of heat-flow problems and suggested its application for certain other problems, such as flow of fluids or mass transfer and chemical diffusion. Necessary details for applying the analogy to flow of fluids in porous media were developed by IV. A. Bruce;= he classified3 the types of analysis and predictions that can be made by the analogy in class I, when the reservoir contains oil but no gas for the period under consideration; in Class 2, when both oil and gas exist in the free state in the reservoir sometime during the period under consideration. Duplication of bottom-hole pressure history and predictions for class I reservoirs can be obtained directly by electric analogy. Until now, the solution of problems pertaining to reservoirs in class 2 was obtained by successive approximations along with material-balance calculations. The object of this paper is to present a method for simplifying the application of electric analogy to class 2 reservoirs, resulting in a solution of these problems as direct as is possible for class I reservoirs. This is accomplished by an electronic control circuit, which adjusts the analogy network for changing compressibilities of fluids contained in the reservoirs. Analogy Network In electrical phenomena the analogy to two-dimensional fluid flow in a porous media is that of current flow through an ideal conducting sheet. This sheet, perfectly insulated on both sides, has resistance and capacitance uniformly distributed throughout its area but is of negligible inductance. The need for having the surface boundaries perfectly insulated is that good correspondence may be had with a permeable fluid-conducting stratum bounded above and below by impermeable media. 111 actual application the ideal conducting sheet, which has distributed parameters, is replaced by a network having lumped values of resistance and capacitance—the resistances are series elements and the capacitances are shunt elements. The larger the number of lumped

Jan 1, 1947

By Henry Schaefer

Solution by electric analogy of performance problems of reservoirs containing oil and gas has heretofore depended upon a process of successive approximations based on material-balance calculations, because of variation in fluid compressibility. By the addition or subtraction of electric condenser capacity, the analogy network can be adjusted automatically for changing compressibility due to evolution of gas in the reservoir. The addition of a condenser is accomplished by an electronic circuit, which is described; subtracting a condenser is done by merely opening the electrical circuit by means of a relay. Introduction V. Paschkis and H. D. Baker1 first developed in this country a method of applying the analogy of flow of electric current in noninductive circuits to solution of heat-flow problems and suggested its application for certain other problems, such as flow of fluids or mass transfer and chemical diffusion. Necessary details for applying the analogy to flow of fluids in porous media were developed by IV. A. Bruce;= he classified3 the types of analysis and predictions that can be made by the analogy in class I, when the reservoir contains oil but no gas for the period under consideration; in Class 2, when both oil and gas exist in the free state in the reservoir sometime during the period under consideration. Duplication of bottom-hole pressure history and predictions for class I reservoirs can be obtained directly by electric analogy. Until now, the solution of problems pertaining to reservoirs in class 2 was obtained by successive approximations along with material-balance calculations. The object of this paper is to present a method for simplifying the application of electric analogy to class 2 reservoirs, resulting in a solution of these problems as direct as is possible for class I reservoirs. This is accomplished by an electronic control circuit, which adjusts the analogy network for changing compressibilities of fluids contained in the reservoirs. Analogy Network In electrical phenomena the analogy to two-dimensional fluid flow in a porous media is that of current flow through an ideal conducting sheet. This sheet, perfectly insulated on both sides, has resistance and capacitance uniformly distributed throughout its area but is of negligible inductance. The need for having the surface boundaries perfectly insulated is that good correspondence may be had with a permeable fluid-conducting stratum bounded above and below by impermeable media. 111 actual application the ideal conducting sheet, which has distributed parameters, is replaced by a network having lumped values of resistance and capacitance—the resistances are series elements and the capacitances are shunt elements. The larger the number of lumped

Jan 1, 1947

By C. A. Gibbons

AFTER nine years of extremely de- pressed business, marked mostly A with red ink on the balance sheets of most coal companies and with an increasing internal competitive struggle for diminishing markets, somewhat of a change appeared during 1939. Shipments increased and prices generally firmed, giving the coal industry increasing optimism and encouragement for the future. Specifically, it now appears that bituminous coal production for 1939 will approximate 378,000,000 tons, and anthracite production will approximate 47,500,000 tons, bituminous production being around 14 per cent ahead of 1938 and anthracite production 12 per cent better. The curve on p. 31, showing both bituminous and anthracite production, furnished by the bituminous coal division of the Department of the Interior, shows graphically most of the 1939 monthly production and clearly illustrates the increased production.

Jan 1, 1940

By SIDNEY ROLLE

ACURSORY glance through the literature on the subject reveals that the ablest minds in the land are devoting themselves to the great question of labor, of which employment is one of the fundamentals. Volumes have been written and the end is not in sight. Employment management is today about in the position that efficiency was 15 years ago. During the early days of the war, and perhaps for a year or so before, labor was plentiful. As the war progressed and Europe drew on us for munitions, employers began to compete with one another for', all, classes of labor. Labor was difficult to obtain, wages rose, the labor turnover increased, and employers began to install employment departments, welfare plans, and all sorts of schemes, but the labor efficiency dropped. As the war progressed, greater and greater production was demanded. New factors were introduced each day. The government, labor unions, industrial councils, all tended, it seemed, to make the situation almost intolerable. Wages rose to fantastic heights, the cost of living rose higher and higher, and the efficiency dropped still further.

Jan 1, 1921

By T. E. Eagan, W. R. McCrackin

IN dealing with segregation in babbitt, and its effect on the final cast structure, which is a bearing, it is obviously impossible to cover all of the compositions manufactured. Each composition, of course, will exhibit certain specific types of segregation. However, as examples,, two compositions of babbitt are presented: one a tin-base of well-known analysis and the other a lead-base, which in the past few years has found wide usage. Bearings usually are cast either statically or centrifugally; therefore the effect of these two methods on segregation is presented. EXPERIMENTAL PROCEDURE A slab of babbitt 1/2 in. thick by 5 in. wide and 17 in. long was cast, using a book mold with the long edge vertical. An A.S.T.M. grade 2 babbitt was used (3.5 per cent copper, 7.5 per cent antimony, remainder tin), to which 0.10 per cent tellurium had been added. Unfortunately, no metal without tellurium was available. The mold to hold the babbitt was heated to approximately 300°F., the temperature being judged by the babbitter. The pouring temperature of the babbitt was 875°F. (470°C.). One slab was made by allowing the babbitt to cool without stirring. The other slab was stirred during the entire cooling cycle. This stirring consisted of a vigorous churning or puddling into the mold until complete solidification had taken place. Three samples were removed from these slabs. One was taken at the extreme bottom, another half way to the top, and another at the extreme top, all at the center of the width. Chemical, macroscopic and microscopic examination was made of all samples. Table I shows the chemical analyses obtained at the described positions [ ] in the slab. The analyses show no serious amount of gravity segregation. Microscopic examination from edge to edge of the slab showed little change in structure. From top to bottom there was a progressive coarsening of the grain size in the stirred slab but little change in the slab that was not stirred (Fig. I). No definite exhibit of segregation could be detected. In line with our experimental study on the tin-base babbitts, we cast an almost duplicate slab using A.S.T.M. Alloy No. 15, containing 0.9 to 1.25 per cent tin, 14.75 to 15.5. per cent antimony, 0.80 to 1.25 per cent arsenic and 0.4 per cent copper. The slab was 16 in. long and 3/8 in. thick, cast with the long side vertical. One slab was allowed to cool normally and the other was stirred continually during cooling. The pouring temperature of the babbitt was

Jan 1, 1944