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By Sidney Powers

Discussion of the paper of SIDNEY POWERS and ALFRED C. LANE, presented at the New York meeting, February, 1916, and printed in Bulletin No. 110, February, 1916, pp. 535 to 548. N. L. BOWEN, Washington, D. C. (communication to the Secretary*). -This detailed study and. complete demonstration of differentiation as a result of the sinking of crystals has a great general significance in petrogenesis. If this action can be demonstrated in an effusive body, even though a very thick one, how can one doubt its possibility in large intrusive bodies? The authors speak of the sinking of augite and the rising of plagioclase but I should consider that they should depend entirely on the former action to obtain their results. It is true that in my experiments, to which the authors refer, a floating of crystals was in one case obtained, viz., in the case of tridymite crystals, but it must be remembered that tridymite has an exceptionally low density. Plagioclase crystals, on the other hand, are of nearly the same density as basaltic liquid. Under magmatic conditions they might be a little heavier than the liquid or a little lighter, we do not know which, but the margin would be exceedingly small and any motion resulting, whether upward or downward, would be correspondingly small in the usual case. For this reason I should think that the sinking of pyroxene should be considered probably the sole factor in producing the observed result, for which purpose it appears to be entirely adequate. The measurements of grain have also a certain significance in this connection. In the experiments referred to a difference of grain was obtained in different parts of the charge, which was entirely independent of the rate of cooling but connected with the fact that a sinking crystal does not depend entirely upon diffusion for the collection of its material from the surrounding liquid. The crystals which sank a considerable distance were therefore exceptionally large. Now in the Cape Spencer flow the augite crystals are normally (top and bottom) somewhat smaller than the plagioclase crystals, but in the layer somewhat below the middle,

Jan 5, 1916

By Hugh M. Roberts

The important place in the economic life of the country that is occupied by the United States Geological Survey and the various state surveys is appreciatcd by most members of our Institute. To the public at large, the functions of these surveys are no doubt largely unknown, and taken for granted. Possibly a realization of the value of the work of these government branches is brought home most fully to that group of our members whose duties as examining engineers and mining geologists take them to mines and prospects in many different parts. The examining engineer or geologist is usually seeking for a judgment on the value of an enterprise from the standpoint of the useful minerals that may or may not be present; he must also attempt some prediction as to future market prices. On his opinion rests the determination of the expenditure of money, which rendered into other language means the expenditure of human effort. An opinion on an exploring venture or the reasoning out of the probable extensions of an orebody requires among many other things a background of knowledge covering the geologic horizons not only of an immediate area but of the surrounding area, a knowledge of the structural geology and of the causes that have operated to form the ores as they are. The great storehouses of this knowledge are the statistics, reports and maps issued by the various geological surveys. They supply the groundwork for additional observations. To these, reference is always made when going into a new district. The technique of work in the field and laboratory, and to some extent the hypotheses that underlie our methods of approach, have been formed by men such as Van Hise, Leith, Kemp, Spurr, Emmons and Lindgren, who developed their powers in the service of the geological surveys. In addition to whatever originality of thought, or power to observe facts and analyze them, may be our portion, we require, in the application of the arts and sciences, a knowledge of what has already been done. We stand on the shoulders of those who have gone before, and the extent of our vision often depends upon the thoroughness with which we form earlier work into one whole and make use of it.

Jan 1, 1935

By Hugh M. Roberts

The important place in the economic life of the country that is occupied by the United States Geological Survey and the various state surveys is appreciatcd by most members of our Institute. To the public at large, the functions of these surveys are no doubt largely unknown, and taken for granted. Possibly a realization of the value of the work of these government branches is brought home most fully to that group of our members whose duties as examining engineers and mining geologists take them to mines and prospects in many different parts. The examining engineer or geologist is usually seeking for a judgment on the value of an enterprise from the standpoint of the useful minerals that may or may not be present; he must also attempt some prediction as to future market prices. On his opinion rests the determination of the expenditure of money, which rendered into other language means the expenditure of human effort. An opinion on an exploring venture or the reasoning out of the probable extensions of an orebody requires among many other things a background of knowledge covering the geologic horizons not only of an immediate area but of the surrounding area, a knowledge of the structural geology and of the causes that have operated to form the ores as they are. The great storehouses of this knowledge are the statistics, reports and maps issued by the various geological surveys. They supply the groundwork for additional observations. To these, reference is always made when going into a new district. The technique of work in the field and laboratory, and to some extent the hypotheses that underlie our methods of approach, have been formed by men such as Van Hise, Leith, Kemp, Spurr, Emmons and Lindgren, who developed their powers in the service of the geological surveys. In addition to whatever originality of thought, or power to observe facts and analyze them, may be our portion, we require, in the application of the arts and sciences, a knowledge of what has already been done. We stand on the shoulders of those who have gone before, and the extent of our vision often depends upon the thoroughness with which we form earlier work into one whole and make use of it.

Jan 1, 1935

By Paul T. Allsman

Passage of the Mining Act of 1866, superseded by the Act of 1872, was the first major entry of the Federal Government into the problems of mining. Such a law was necessary simply to help re- solve a number of disputes in mining. Now, however, a hundred years later, the extent of government involvement in the mineral industry often comes as a shock to the mining engineer who has reached management level. In fact, he has been poorly prepared for an understanding of the role of government in the industry and he becomes frustrated, even hostile. In our political system, private industry is responsible for producing minerals and the Government sees to it that production will be adequate for a peace-time economy and for any emergency. There have been great social and political changes since World War I1 with the result that the Government's participation in our society has steadily increased. A new dimension in business and government relations has been introduced which should be examined more closely.

Jan 5, 1966

By C. McDermid

At the request of Mr. C. McDermid, Secretary of the Institution of Mining and Metallurgy, Salisbury House, London, E. C., England, the following reports of standardization committees are here republished. Mr. McDermid invites members of-the American Institute of Mining Engineers to write him and express their opinion of the various proposals made by the committees. COPY OF THE REPORT OF THE WEIGHTS AND MEASURES STANDARDIZATION COMMITTEE OF THE INSTITUTION OF MINING AND METALLURGY, as adopted by the Central Standardization Committee; Dec. 20, 1906, and submitted to the Council, Jan. 16, 1907.

Mar 1, 1907

By George A. Guess

The increasing demand for greater speed and more accuracy, in making daily assays of ores and products from mills treating material containing but very small quantities of lead and copper, has caused the older analytical methods to be supplanted by new ones devised to meet the needs of modern work. For " control" work in copper-analyses, I had, previous to the present equipment, introduced in my laboratory the ordinary electrolytic method, using hollow cylindrical electrodes; and with these I began a series of experiments in determining the lead-content of daily mill-samples and controls. The results, proving accurate and satisfactory, I then devised, with Mr. H. E. T. Haultain, a cheaper electrode than the ordinary jaCket-electrode, which costs from $15 to $20,—the expense of the older form making the installation of many units very costly. The form of cathode finally adopted as the most satisfactory, shown in Fig. 1, is cut from 0.001-in. platinum foil. It is 12.5 cm. long, and is divided into a blade 4 cm. wide and 6.25 cm. long, and a tongue 0.7 cm. aide and 6.25 long, the immersion area being 50 sq. cm. and weight 1.5 grams. The blade is first sand-blasted and then corrugated lengthwise, in order to impart the necessary rigidity. Strips of platinum foil 0.001 in. thick, 12.5 cm. long and 0.5 cm. aide, having a median corrugation, form the anodes. Three electrodes are used in each cell; one anode in the middle and one cathode on each side of the anode. These electrodes are connected to slotted aluminum terminals, in which they are held by contact pressure. The terminals are 5/16in. rods, projecting 2 in. horizontally in front of the wall of the cabinet; at the back the middle electrode (anode) is connected with one pole of the current, and the two outer ones (cathodes) with the other pole.

Jan 1, 1906

By D. L. Katz

In the management of oil properties, it is always desirable to know the future behavior of oil wells and oil reservoirs. Some estimation of the quantity of oil and gas that will be produced must be made as a basis for decisions on possible returns on investments in lifting equipment, drilling of additional wells, and other operating expenditures. In new or wildcat areas, operating expenditures are considered highly speculative, but in the completion of partly drilled and the operation of producing fields it is good business to remove as much speculation as possible. An accurate knowledge of oil and gas reserves in such cases would solve many management problems. The term "oil reserves" usually signifies the future ultimate recovery without specifying the method of production. Thus with changing methods and innovations in the production industry, reserves of any definite reservoir may be increased by increasing the portion of oil recovered. The usual reserve estimates are made by comparisons of well and formation characteristics, by using a percentage recovery on the oil content of the formation volume using porosity data, by extending production curves on non-prorated wells, or by extending bottom-hole pressure-production curves. The most reliable method would appear to be one that would estimate the initial quantity of oil and gas present and then obtain percentage recovery values for various productive methods and formations from experience. It is the purpose of this paper to describe a method of estimating the initial quantity of oil and gas present in a reservoir. The method is based on field operating data and the properties of crude oil-gas mixtures. The principles involved, the data required, the assumptions necessary, and an example of the method will be given. The method is entirely independent of sand volumes and formation porosities. Principles of Method The method of estimating the initial quantity of oil and gas present is based upon the premise that the volume occupied by oil and gas in the reservoir is constant and that a mixture of crude oil and gas will behave in

Jan 1, 1936

By D. L. Katz

In the management of oil properties, it is always desirable to know the future behavior of oil wells and oil reservoirs. Some estimation of the quantity of oil and gas that will be produced must be made as a basis for decisions on possible returns on investments in lifting equipment, drilling of additional wells, and other operating expenditures. In new or wildcat areas, operating expenditures are considered highly speculative, but in the completion of partly drilled and the operation of producing fields it is good business to remove as much speculation as possible. An accurate knowledge of oil and gas reserves in such cases would solve many management problems. The term "oil reserves" usually signifies the future ultimate recovery without specifying the method of production. Thus with changing methods and innovations in the production industry, reserves of any definite reservoir may be increased by increasing the portion of oil recovered. The usual reserve estimates are made by comparisons of well and formation characteristics, by using a percentage recovery on the oil content of the formation volume using porosity data, by extending production curves on non-prorated wells, or by extending bottom-hole pressure-production curves. The most reliable method would appear to be one that would estimate the initial quantity of oil and gas present and then obtain percentage recovery values for various productive methods and formations from experience. It is the purpose of this paper to describe a method of estimating the initial quantity of oil and gas present in a reservoir. The method is based on field operating data and the properties of crude oil-gas mixtures. The principles involved, the data required, the assumptions necessary, and an example of the method will be given. The method is entirely independent of sand volumes and formation porosities. Principles of Method The method of estimating the initial quantity of oil and gas present is based upon the premise that the volume occupied by oil and gas in the reservoir is constant and that a mixture of crude oil and gas will behave in

Jan 1, 1936

By Donald D. Carr, Lawrence F. Rooney

Perhaps no other mineral commodity in this volume has as many uses as limestone and dolomite. These carbonate rocks are the basic building blocks of the construction industry, the material from which aggregate, cement, lime, and building stone are made. Carbonate rocks, and their derived products, are used as fluxes, glass raw material, refractories, fillers, abrasives, soil conditioners, ingredients in a host of chemical processes, and much more. Although the use of limestone and dolomite goes back before recorded history, new uses and products are continually being found. Carbonate rocks form about 15% of the earth's sedimentary crust and are widely available for exploitation. Found extensively on all continents, they are quarried and mined from formations that range in age from Precambrian to Recent. Reserves of carbonate rock are large and will last indefinitely, although high-purity deposits may be absent or have limited avail- ability in certain areas. Limestone and dolomite are so useful and so abundant that in 1972 more than 690 million tons were produced in the United States. In fact, about 75% of all stone quarried or mined in the United States was carbonate rock. Sand and gravel was the only mineral commodity produced in greater quantity. In this chapter we have sought to provide the general reader an overview of carbonate rocks, their composition, distribution, production, and uses, with emphasis on developments since 1960. In doing so we borrowed extensively from our recent report on the applied geology of limestone and dolomite (Rooney and Carr, 1971). The literature on the limestone and dolomite resources of the United States and Canada is so vast and diverse that one can easily become mired down in print. We tried to list those references that are easily accessible and that provide the economic geologist with a starting point for more intensive study. The table listing selected references on limestone and dolomite resources in Canada and the United States reflects our attempt to be selective rather than exhaustive and to direct the reader to the best sources of detailed information.

Jan 1, 1975

George W. Maynard, New York, N. Y.:—It is well known that there are many magnetite-mines of which the ore is too low-grade for direct use in the blast-furnace. For carrying out the sintering process, the preliminary step, in the case of magnetites, is the separation of the ore from the gangue by magnetic concentration. The resulting fine-grain product is very objectionable in the blast-furnace, and when used must be a very small percentage of the charge. The sintering process has saved the situation by furnishing a product which is absolutely ideal on account of its cellular structure. (In reply to questions by W. J. Tudor, and Joseph W. Richards, the following additional information was given by Dr. Maynard.) The percentage of iron in the product is determined entirely by the degree of concentration of the raw material and is practically not increased by the sintering operation. The magnetic concentrates at Port Henry and at the Benson and one or two other mines contain from 65 to 67 per cent. of metallic iron. The cost of sintering is from 39 to 41 cents per ton of product, including superintendence, depreciation, and repairs. The itemized figures are about as follows : Mixing (including labor), 24; power, 9; ignition, 5; repairs, 3; total, 41 cents. Prof. J. W. Richards, South Bethlehem, Pa.:—From a metallurgical standpoint I question the accuracy of the statement on p. 374: " C.—An increased reducibility of the iron so treated. (This has been conservatively estimated as 5 per cent. better than the best available ore.)" It seems to me that when a material is' sintered in this way, the constituents present, as lime, silica, and alumina, have a chance to form a compound with the iron oxide; that such a compound, if formed before the material goes into the blast-

Jan 1, 1913

By A. J. Phillips, C. G. Grant, Wm. B. Price

Admiralty nickel is a new corrosion-resisting and heat-resisting white metal alloy composed of 70 per cent. copper, 29 per cent. nickel and 1 per cent. tin. It has been given the trade name "Adnic." In 1924, Wm. B. Price' described this alloy and its successful use as a diaphragm metal. The physical properties of Adnic at ordinary and elevated temperatures were given in Mining & Metallury.~ A patent3 was granted on Adnic, April 28, 1925. Work was first started on this alloy during December, 1921. An investigation of the patent situation in this country and abroad, and also a search of the literature, did not reveal any work on the ternary diagram, copper-nickel-tin; and the only wrought copper-nickel-tin alloy found was that known as "Newloy," composed of copper, 64 per cent.; nickel, 35 per cent.; tin, 1 per cent. This was being manufactured and sold by Wm. Gallimorr & Sons, Ltd., Sheffield, England, for unplated spoon and fork stock, and first came to our attention in January, 1922. The preliminary work in connection with the development of Adnic was started by casting four binary copper-nickel alloys of the compositions shown in Table 1. Various a~ilounts of tin were added to each of these mixtures, to produce the series of ternary copper-nickel-tin alloys also given in Table 1. A 200-gm. sample of each of these was cast by iiielting in a clay graphite crucible and allowing the melt to slowly cool with the furnace. A longitudinal section from each of thcsc castings was polished and etched for examination. The castings were not homogenrous solid solutions, but showed the usual cored structure associated with cast alloys. Howcvrr, frorn an exarrlination of these sections we roughly determined

By R. E. Reed, R. D. Leggett, Paxton, H. W.

TECHNIQUES have been developed for growing monocrystals and bicrystals of Fe-20 Cr, Fe-20 Cr-20 Ni, and Fe-18 Cr-8 Ni alloys by both the strain-anneal and the Bridgeman techniques. None of the techniques are new but since they are simple and many people have expressed interest, they are described here quantitatively as they could be modified for other single-phase "commercial" materials of high melting point. CRYSTAL GROWTH BY STRAIN ANNEAL Flat tensile specimens with a tapered gage length were initially studied to deduce the approximate critical strain. Normal flat tensile specimens were then used. The optimum procedure for the austenitic steels (Fe-Cr-Ni) deduced from a variety of cold reductions, recrystallization treatments, tensile strain, and growth anneals was as follows: cold reduce 70 pct, recrystallize (after machining tensile specimens) at 1000°C for 1 hr, strain in tension 2.5 pct, and then heat to 1350°C as rapidly as possible. A time of 100 hr at 1350°C is usually sufficient to pro-

Jan 1, 1960

By Geo. H. Ashley

THE present critical state of the supply, distribution, and utilization. of coal and the necessity for pooling and zoning coals calls renewed attention to the lack of any fully adequate classification of coal. In the past coals have been classified as anthracite, semianthracite, semibituminous, bituminous, subbituminous coals, and lignite, and a few special types, such as splint coal and cannel coal. But under the term bitumi¬nous coal are included a great variety of coals differing markedly both physically and chemically. The term subbituminous coal covers as great a range of chemical differences. In order to distinguish these varieties of bituminous coals it has been customary to designate coals by names derived from the place where mined, or by the name of the bed from which it is mined. Thus, in the market reports, coals are quoted as Pocahontas coal, New River or Sewell coal, Moshannon coal, Ohio coal, Williamson County coal, Jellico coal, and so on indefinitely, no limit being set as to the boundaries of the area to which a given name is applied. Nor is there any scale by, which the coal from one place may be compared with the coal from some other district or some other bed. On the one hand, coals from the same district may be quite distinct and sell at very different prices or coal from the same bed may differ greatly in different districts; on the other hand, coals from different states may be so similar physically and chemically that one could replace the other in practical use without any appreciable difference in service.

Jan 8, 1919

By S. D. Michaelson

[CONTENTS PACE See TP 2377, Min. Tech, May 1948 for discussion of A Technique for Photographing Difficult Subjects through a Petrographic Microscope (TP 2092 by DONALD W. SCOTT, Min. Tech., Nov. 1946. Discussion by HORACE WINCHELL). Metallurgical Efficiency-a Yardstick in Lead-zinc Flotation Metallurgy (TP 2141 by R. A. ....... PALLANCH, Min. Tech:, March 1947. Discussion by S. D. MICHAELSON). I Symposium on Milling Devices and Practices. (TP 2162 by J. F. MYERS and R. J. TOWER, Min. Tech., May 1947. Discussion by HARLOWE HARDINGE). ............ 2 Rod Milling-Plant and Laboratory Data. (TP 2175 by J. F. MYERS, S. D. MICHAELSON and F. C. BOND, Min. Tech., July 1947. Authors' supplement and discussion by HARLOWE .......................... HARDINGE, and B. H. IRWIN) 2 A New Separating Vessel for Sink-float Concentration. (TP 2182 by E. C. BITZER, Min. Tech., May 1947. Discussion by E. H. CRABTREE, JR.) .................. 5] Metallurgical Efficiency-a Yardstick in Lead-zinc Flotation Metallurgy S. D, MICHAELSON*-The method of determining the efficacy of a separation described in this paper, gives the metallurgist a most useful guide for keeping his ship on an even keel When the ore Waves vary from placid seas to high breakers. Now that such a method of evaluating metallurgical efficiency has been developed and proven practical, it Would seem logical to introduce the next, and more final, factor of Economic Efficiency. I choose to define this term as the percentage ratio of net return from milling to the theoretical maximum net return. The actual operating cost subtracted from the actual mill return represents the net actual amount received for the material treated. Experienced operators of most plants Would ordinarily have enough data on hand to estimate a theoretical milling cost per ton, based on labor, power, supplies and maintenance When operating at maximum tonnage With minimum trouble and under ideal ore conditions. When this theoretical estimated cost is subtracted from the theoretical maximum ore return (calculated by Pallanch's method) the resulting figure is the maximum theoretical net amount the mill operator could hope to realize in processing the ore. The percentage ratio of these sums, of actual to theoretical, is the economic efficiency of the operations. This economic efficiency, if determined on the basis of a fixed market price for metal and similarly fixed base rates for labor, power and supplies, Will reflect the effect of changes in milling practice, labor efficiency and equipment condition. When computations made on the basis of actual current rates for labor, power and supplies are compared With similar actual figures for past periods they will show forcefully how energetic our hunt must be to develop man saving controls, more effective metallurgy, and better equipment to maintain profitable operations. Such computations also offer a simple means of determining how much more labor, supplies and power can be put into the mill operation to obtain an increase in metallurgical recovery at a profit.

Jan 1, 1947

By G. S. Hume

ACTIVE drilling operations for oil were carried on during the summer of 1923 in various parts of, western Canada, particularly in Alberta. During the early part of the summer, interest centered in southern Alberta, in the Coutts area, just north of the producing Kevin-Sunburst field of Montana; but on Nov. 14 a strike of oil by British Petroleums Ltd. at its well near Wainwright, 120 mi. east of Edmonton, diverted public attention to a new field. According to present estimates, this well has a possible production of from 60 to 100 bbl. a day; the oil is 15° Be. with an asphaltic base and is obtained from a sand at the depth of 2019-2036 ft. The oil stands at 1700 ft. in the casing and there is sufficient gas pressure to cause it to flow when the well is opened. The oil horizon is in a sandstone in rocks of Colorado age. It is known that there is a terrace structure of which the western edge extends in a northwesterly direction from the vicinity of Hardisty to Viking, where it probably swings more to the north. At Viking a small dome-like structure on this terrace gives rise to an important gas field. Wainwright lies directly northeast of Hardisty. The exact structure in the Wainwright field is unknown. At Fabyan, 6 mi. northwest of Wainwright, the Imperial Oil Co.1 last year brought 1n a large gas well estimated at 14,000,000 cu. ft.; the escaping gas sprayed a small amount of heavy black oil over the derrick. The gas was obtained at a depth of 2727 ft., deeper drilling encountering a water sand. The results of drilling in the Wainwright field are encouraging for future development.

Jan 3, 1924

DESPITE the very small number of engineers who can get away from their tasks to New York, a point so far from the Mid-Continent and Cali-fornia oil fields, where the real important, engineering progress in the industry is being made, the attendance was remarkably good, and it was generally remarked that all the sessions were "snappy," and there was no drag. This was largely because, under instructions from the chairman, very few papers were permitted to be read, and the "high lights" of each paper were pre-sented orally as an introduction to the large and varied discussions, many of which were prepared in advance. The round table discussion on petroleum engineering research problems, conducted by W. E. Wrather, proved a greater success than was anticipated, considering the difficulty in getting many of the men to discuss such problems. There has been no crystallization of opinion heretofore of what are important engineering research problems, as distinguished from pure science problems, and a digest of the discussion will be made available so as to present the results obtained. It is hoped that further round table discussions, as well as committee work, in the meantime summarizing problems appear-ing in papers published the last two to three years, will enable the oil industry to determine intelligently which of the problems are most important for immediate attack. The roundtable discussion on petroleum engineering educational problems, conducted by H. C. George of the University of Oklahoma, was equally fruitful, and since managers of companies, consulting engineers, and pro-fessors cooperated in these sessions, a cross-section of their opinions on improving the curricula for training the large number of petroleum engineers, which the industry can absorb in-the next few years, was obtained.

Jan 3, 1927

By J. A. M. van Liempt

SINCE the discovery of von Laue, that a crystal forms a natural grating for X-rays, our knowledge of the structure of solids has gone forward with rapid strides. This progress is not only of purely scientific interest, but has also yielded direct technological results. One of the most valuable results is the broadening of our knowledge of the structure of pure metals and alloys. To promote these studies it is often desirable to have at our disposal pieces of metal consisting of one single crystal. As is so often the case in the natural sciences, we obtain the best results by making our earliest experiments on pure, simple materials and avoiding unnecessary complications. The Cryogen Laboratory at Leyden followed this method with much success, because the work was done at such low temperatures that the heat movement of the atoms was almost absent. Similarly we can simplify the studies of metals by leaving out of consideration the influence of the grain boundaries and the mutual influence of the crystals by using unicrystalline instead of polycrystalline metal. Methods of making single crystals have been scientifically studied during the past few years. Some methods were already known in the arts, but these have been improved and new methods have been developed. The methods for making metallic single crystals may be divided into the following groups: A. From the liquid state B. From the gaseous state C. Electrolytically D. By recrystallization in the solid state METHOD A 1. Tammann's Method. 1-Tammann succeeded in making bismuth single crystals of a maximum length of 20 cm. by undercooling the molten metal 0.1 to 0.3° G. below its melting point in glass tubes of a maximum

Jan 1, 1928

By J. A. M. van Liempt

Since the discovery of von Laue, that a crystal forms a natural grating for X-rays, our knowledge of the structure of solids has gone forward with rapid strides. This progress is not only of purely scientific interest, but has also yielded direct technological results. One of the most valuable results is the broadening of our knowledge of the structure of pure metals and alloys. To promote these studies it is often desirable to have at our disposal pieces of metal consisting of one single crystal. As is so often the case in the natural sciences, we obtain the best results by making our earliest experiments on pure, simple materials and avoiding unnecessary complications. The Cryogen Laboratory at Leyden followed this method with much success, because the work was done at such low temperatures that the heat movement of the atoms was almost absent. Similarly we can simplify the studies of metals by leaving out of consideration the influence of the grain boundaries and the mutual influence of the crystals by using unicrystalline instead of polycrystal-line metal. Methods of making single crystals have been scientifically studied during the past few years. Some methods were already known in the arts, but these have been improved and new methods have been developed. The methods for making metallic single crystals may be divided into the following groups: A. From the liquid state B. From the gaseous state C. Electrolytically D. By recrystallization in the solid state Method A 1. Tamwmnn's Method1—Tammann succeeded in making bismuth single crystals of a maximum length of 20 cm. by undercooling the molten metal 0.1 to 0.3' G. below its melting point in glass tubes of a maximum

By James R. Cudworth, Joseph C. Mead

The Birmingham district of Alabama has utilized the slag from its blast furnaces consistently since the earliest development of the slag industry. Today there are producers of slag cement who started business in 1900, and who have, under a progressive policy, expanded the number of their products to meet present demands. There are producers of slag aggregates and other crushed slag products who have been successful for periods of over thirty years. There are at the present two companies, Cheney Lime and Cement Co. and the Southern Cement Co., manufacturing puzzolan cement; two companies, Birmingham Slag Co. and Woodstock Slag Co., making slag aggregates and by-products; one company, Tennessee Coal, Iron and Railway Co., a subsidiary of the U. S. Steel Corporation, producing ground open-hearth basic slag for soil conditioning. Two companies, the Sloss Sheffield Steel and Iron Co. and the Woodstock Slag Co., make slag concrete in ready-mix plants and one company, the Superock Company, manufactures fine and coarse slag aggregates under a new granulation process. NO Portland cement is made with slag as an ingredient, because dolomite is used so extensively as a blast-furnace flux that the magnesium content of the slag is excessive. Sources of Slag In the Birmingham district there are 22 blast furnaces, of which the majority are in blast. The present production is 165,000 tons of pig iron monthly; the production in 1935 was 1,297,960 gross tons1. There arc also two blast furnaces at Gadsden and one ferroalloy electric furnaee at Anniston. From these two sources is obtained slag to approximately 1.1 tons per ton of pig iron. History of Development of the Industry The history of the local utilization of slag as an industry probably starts with the Birmingharii Slag Cement Co. This company was

Jan 1, 1938

By Joseph C. Mead, James R. Cudworth

The Birmingham district of Alabama has utilized the slag from its blast furnaces consistently since the earliest development of the slag industry. Today there are producers of slag cement who started business in 1900, and who have, under a progressive policy, expanded the number of their products to meet present demands. There are producers of slag aggregates and other crushed slag products who have been successful for periods of over thirty years. There are at the present two companies, Cheney Lime and Cement Co. and the Southern Cement Co., manufacturing puzzolan cement; two companies, Birmingham Slag Co. and Woodstock Slag Co., making slag aggregates and by-products; one company, Tennessee Coal, Iron and Railway Co., a subsidiary of the U. S. Steel Corporation, producing ground open-hearth basic slag for soil conditioning. Two companies, the Sloss Sheffield Steel and Iron Co. and the Woodstock Slag Co., make slag concrete in ready-mix plants and one company, the Superock Company, manufactures fine and coarse slag aggregates under a new granulation process. NO Portland cement is made with slag as an ingredient, because dolomite is used so extensively as a blast-furnace flux that the magnesium content of the slag is excessive. Sources of Slag In the Birmingham district there are 22 blast furnaces, of which the majority are in blast. The present production is 165,000 tons of pig iron monthly; the production in 1935 was 1,297,960 gross tons1. There arc also two blast furnaces at Gadsden and one ferroalloy electric furnaee at Anniston. From these two sources is obtained slag to approximately 1.1 tons per ton of pig iron. History of Development of the Industry The history of the local utilization of slag as an industry probably starts with the Birmingharii Slag Cement Co. This company was

Jan 1, 1938