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No phase of the steel industry is more typical of its remark- able progress than is the evolution and development of the modern American blast furnace. The founding of the Institute in 1871 also marked the beginning of a new era in the pig-iron industry. The rapidly expanding westward development of the country, with its seemingly unlimited markets, gave rise to unprecedented demands for blast-furnace products. The manner in which the iron industry responded provides a fascinating chapter in the history of industrial development. Prior to this period, the iron industry of the United States, largely concentrated in the East, was based upon the consumption of local iron ores and local fuels, the latter predominately charcoal and anthracite. Small, isolated furnaces were located near scattered ore and fuel sources, and the completely integrated ironworks and steelworks were yet to be developed. In about 1860 exploitation of the newly discovered rich ore deposits in Michigan and the successful adaptation of blast furnaces to coke produced from coal of the great Pittsburgh seam in western Pennsylvania proved to be major factors in firmly establishing the general westward shift of the industry. But these were largely economic in character, and it was not until about 1870 that the aggressive, individualistic nature of the ironmaster asserted itself in no uncertain manner. No longer limited by relatively inadequate equipment and inferior raw materials, and spurred as well as encouraged by those who supplied capital for these new enterprises, furnacemen began to establish unheard of records in iron production. It is not surprising that Pittsburgh was the center of this new activity. Its tenor is best indicated by the following account :l

Jan 1, 1948

By C. G. Rhodes, D. Kramer

High-field critical transport current density (J) measurements at 4.2 °K as a Junction of applied magnetic field (H) were made on samples of cold-rolled and annealed columbium with H parallel to J. Microscopic examination of the samples revealed a well-defined planar fiber structure produced by the cold rolling. J was found to he lower when fibers are parallel to the direction of magnetic field penetration than when they are perpendicular. This effect may he a consequence of the interaction of flux movement with fiber boundaries. THE severe changes in microstructure brought about by cold working superconductors leads to profound changes in their superconducting behavior. In particular, the ability of a superconductor to carry a transport current with zero resistance (the maximum value of this current density will be called "J" in the presence of large external magnetic fields (to be referred to as "H") is greatly influenced by the microstructure. In the case of columbium, LeBlanc and Little1 and Autler et a1.2 have observed an increase in J due to cold work. LeBlanc and Little also observed an anisotropy in J in cold-rolled columbium strips, which Hake et al.3-6 have shown to depend upon the angle between H (H ? J) and the rolling plane. An increase in J due to cold work has been found in a variety of high-field superconducting alloys3'4'7-9 as has the anisotropy effect.10 First explanations of why cold work raised J invoked the idea that dislocations carried the high-field supercurrents,8,11 since cold working drastically increases the dislocation density and presumably the number of supercurrent paths. However, recent ideas on the nature of high-field superconductivity together with new experimental evidence reveal that the bulk of certain superconductors can remain superconducting in high fields while carrying high transport currents. These later developments have been discussed by Berlin-court and Hake12 and a comprehensive review has been prepared by Berlincourt.13 According to the ideas of Gorter14 and Anderson,15 one would expect that the influence of microstructure on high-field supercurrent density will depend on tine interaction between microstructure and penetrating flux and on the direction of the Lorentz

Jan 1, 1965

By A. A. Dor

Out of nine new major iron ore concentrators put in operation during the last three years, or expected to be commissioned in 1968, seven incorporate primary grinding mills and have a total design capacity of 13,150,000 ltpy of pellets, while only two include conventional rod and ball mill grinding circuits for a total design capacity of about 6,100,000 ltpy (Table I). This evolution in the application of primary grinding to hard, fine grained magnetite ores represents an important development in the technology of mineral processing. It has been the outcome of comprehensive testwork in the laboratory and in pilot plants.

Jan 11, 1968

By K. E. Nelson

The effect of thorium and zinc variations on the strength and 100-hr creep characteristics of Mg-Th-Zn-Zr alloys was investigated. Optimum resistance to creep at 650° and 700°F are attainable within a certain range of thorium and zinc contents. This range does not conform to that which develops maximum tensile properties. RAPID advances have been made during the last few years in the development of magnesium alloys for elevated temperature applications demanding high resistance to creep. The beneficial effect of rare-earth metals on the creep resistance of magnesium alloys has been emphasized by a number of publications1-13 and such alloys are now in commercial production. The use of thorium as an alloying ingredient in magnesium was mentioned by McDonald and also in two Alien Property Custodian patent applications.10,17 The initial observation of Sauerwald that thorium contributes still higher creep resistance to magnesium than is attainable with rare-earth metals has recently been substantiated.'" " In fact, it has been demonstrated that the useful temperature range of magnesium alloys is appreciably extended by the use of thorium. In all cases, it was observed that zirconium must be included in the alloys in order to render them fine grained and more readily castable. Several recent publications:2-27 indicate that a still further improvement in creep resistance and a further extension of the useful temperature range can be realized by the addition of zinc to alloys. The primary purpose of this paper is to present the results of a comprehensive study of the effect of zinc on the strength and creep characteristics of Mg-Th-Zr alloys. Compositions covering the range of thorium content from M to 6 pct and zinc content from 0 to 5 pct have been investigated. The creep characteristics at 650" and 700°F reported in this paper are based on results of tests of 100-hr duration. It is appreciated that creep tests of 100-hr duration might not yield adequate data for design purposes for parts with much longer expected life. However, for the purposes of the present discussion, it is felt that the combination of stresses and temperatures used in the 100-hr creep tests have yielded a clear representation of the compositional variation of creep resistance at the temperatures investigated. Creep tests of 1000-hr duration are now in progress on a few of the most promising alloys. Preparation and Testing of Alloys The alloys studied in this intensive investigation were prepared in 25 lb capacity mild steel crucibles. The thorium, zinc, and zirconium were alloyed and poured as described in earlier publications The thorium was introduced into the melt in the form of a Mg-Th hardener," the zinc added in the metallic form, and the zirconium alloyed in the form of the commercial hardener containing magnesium and 30 to 50 pct Zr.10, 26 Fluxing practices for melting and refining were the same as for magnesium-rare-earth metal-zirconium alloys. The melts were sampled for analytical determinations and poured into separately cast 1/2 in. diameter standard tensile bars. The test bars were given a precipitation treatment of 16 hr at 600°F in laboratory furnaces. It has been shown by other tests that a high temperature solution treatment followed by an aging treatment is unnecessary for the development of optimum properties in Mg-Th-Zn-Zr alloys. The selection of 600°F as the aging temperature was based on an attempt to achieve metallurgical stability without coalescence of the undissolved phases and the attendant loss in strength. The thorium, zinc, and zirconium contents of each melt were determined chemically. The zirconium contents are reported in two parts, "soluble" and "insoluble," referring, respectively, to the portions present in the alloy which are soluble and insoluble in dilute HCl acid. Distinction is being made between these two components of the zirconium content in the alloys because it has been found that only that portion of the zirconium content which is soluble in dilute inorganic acids affects the structure and properties of the alloys. The usual impurities consisting of copper, iron, manganese, and nickel were determined spectroscopically. The analysis for each melt is listed in Table I. A description of the methods of tension and creep testing has been detailed in earlier papers. The tests were performed with the cast skin re-

Jan 1, 1954

By PHILIP N. MOORE

IT is a pleasure to realize even at that day the dignity of the engineer's calling was upheld. May I also add my firm belief that today there be many engineers who will qualify to the specifications of our interesting author. Since that time, the development of the world has been chiefly due to the engineer, and so far as human brain can foresee, the material tasks of the future will continue to follow the directions of his judgment. Popular opinion says this is the age of the engineer; literature, which in the long run, voices public sentiment, shows it in the number of engineers who figure as characters of fiction. The engineer has been doing the big things necessary to increase the comfort and efficiency of mankind, but while a certain amount of fame and repute falls to him, too often he figures as the hired man of the entrepreneur, using that term not in the offensive sense of a mere promoter, but to mean the great visioned master of enterprise who has seen ahead of other men, recognized the coming needs of the world, and through ability to inspire others and to hire capital for his use has also been able to hire engineers as needed. Justly enough, therefore, to such men comes the fame as well as the prize of the game.

Jan 1, 1926

By William H. Kobbé

THE CHAIRMAN (M. L. REQUA, San Francisco, Cal.).-We have had in California a great deal of trouble from the breaking. off and collapsing of well casings from shifting sand, and it is quite true with us as indicated in the paper, that no casing has been found sufficiently strong to withstand that. I know of wells in which casing that has not been in the hole over 2 or 3 days has collapsed and when that casing has, been pulled out it has been just as flat as your hand. I am also familiar with swelling bed rock in the gold drift mining ground of California. It does swell and keeps on swelling and never seems to stop. Just as long as tunnels are kept open in that kind of material there has to be a gang going through the tunnel constantly cutting out and easing up. They have put in timbers 24 in. in diameter in an effort to hold that kind of ground and it has always filled. The only way to succeed is to keep a gang of men busy all the time cutting out and easing down as it squeezes in. C. NARAMORE, Washington, D. C.-My experience has been very similar to yours in, the same field in the matter of breaking off of casing. I had charge of one well, in which I put in reënforced casing, anchored it in place and got 1 day's production, 150 bbl., out of it. The following morning my lease foreman telephoned that it had broken off. I thought at that time we would have more evidence, so I drove out to the well without ordering a new shoe joint. It had been customary to merely start from town with a new shoe joint, pull the pipe, take off the crooked bottom joint, start the casing back and sometimes never touch any iron (lost casing)- when redrilling the well. Where the flattened joints went

Jan 4, 1917

By James E. York

THE honor so fairly earned and so incompletely and tardily paid to Henry Cort, the inventor of the puddling-furnace and the, rolling-mill, has been fully set forth by Mr. Charles H. Morgan,1 and needs no further emphasis here. In view of the importance of the rolling-mill in the treatment of iron and steel, the paucity of information concerning it is surprising. With the exception of a hook, written about 35 years ago, by Peter Bitter von Tunner, an Honorary Member of this Institute, and of desultory articles on simple sections, which have appeared in technical journals, I know of no pub¬lication attempting to treat this subject, although volumes have been written on the scientific theory and technical manipulations involved in other branches of the iron- and steel-industry. This strange anomaly may be due to the fact that roll-turning cannot be called a scientific business. It does not ordinarily come within the range of an educated engineer; yet it cannot be performed by an ordinary mechanic. It demands some of the qualifications of an engineer, in designing, and those of a mechanic, in execution. The men who have followed this trade have controlled the training of their successors. In many cases the technical knowledge required bas been handed down from father to son, and there has been a motive of private interest to prevent its public dissemination. Moreover, the statement of the various principles involved in the process would require, besides manual experience, a degree of scientific knowledge which roll-turners do not usually possess; and, finally, any book on the subject, in order to possess real, practical value, would have to be so fully illustrated as to make it very costly to publish. Regarding my own experience, I may say that I served a six-

May 1, 1906

By J. W. Hickman, E. A. Gulbransen

One of the important factors that determine the resistance of a metal or alloy to further chemical reaction is the structure of the superficial oxide film. A thorough understanding of the physical and chemical structure as well as the stability of the oxide film formed on the surface as a function of time and temperature of the chemical reaction might furnish clues as to the nature of the reaction process and the protective nature of the film. A comprehensive program has been undertaken to study these phenomena. This paper summarizes the structure of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper at temperatures up to 700°C. Before the introduction of the electron diffraction technique, it was necessary to use either direct chemical analyses or X-rav diffraction analyses to determine the nature of the oxide film formed on the metal or alloy. Chemical analyses yields information on the percentages of the several atomic species present in the film while X-ray diffraction analyses yield information on the atomic geometry. In special cases the information obtained may be identical, but in general both viewpoints are necessary. Much of the early work was carried out on the oxidation of bulk samples where thick films were obtained. The products were identified after cooling to room temperature by X-ray diffraction and chemical analyses. Although much useful information has been obtained in this manner. little could be learned about the character of the protective oxides during the period when the films were actually protective. Evidence concerning the chemical structure of thin oxide films has been made possible by the development of the electron diffraction reflection technique. In this method the most fruitful investigations have been made by carrying out the reaction in situ at the temperature at which the film is actually protective. Literature The oxidation of iron has been extensively investigated by X-ray and electron diffraction. Jackson and Quarrelll found that oxide films formed and examined at the same temperature differed considerably from those allowed to cool to room temperature. The results showed that below 400°C the oxide that was stable in intimate contact with iron was Fe³O4; between 515° and 900°C. the stable film was FeO. Above the upper change point of iron the oxide was found to be Fe³O4. From 400' to 515°C., FeO, Fe³O4 or a mixture of the two oxides was found. Recrystallization of the air-formed film below 400' and above 900°C. led to the formation of Fe3O4. In the range where thicker films consisted of FeO, the air-formed film was converted to a new hexagonal oxide not previously described.

Jan 1, 1947

By E. A. Gulbransen, J. W. Hickman

One of the important factors that determine the resistance of a metal or alloy to further chemical reaction is the structure of the superficial oxide film. A thorough understanding of the physical and chemical structure as well as the stability of the oxide film formed on the surface as a function of time and temperature of the chemical reaction might furnish clues as to the nature of the reaction process and the protective nature of the film. A comprehensive program has been undertaken to study these phenomena. This paper summarizes the structure of the oxide films formed on the metals iron, cobalt, nickel, chromium and copper at temperatures up to 700°C. Before the introduction of the electron diffraction technique, it was necessary to use either direct chemical analyses or X-rav diffraction analyses to determine the nature of the oxide film formed on the metal or alloy. Chemical analyses yields information on the percentages of the several atomic species present in the film while X-ray diffraction analyses yield information on the atomic geometry. In special cases the information obtained may be identical, but in general both viewpoints are necessary. Much of the early work was carried out on the oxidation of bulk samples where thick films were obtained. The products were identified after cooling to room temperature by X-ray diffraction and chemical analyses. Although much useful information has been obtained in this manner. little could be learned about the character of the protective oxides during the period when the films were actually protective. Evidence concerning the chemical structure of thin oxide films has been made possible by the development of the electron diffraction reflection technique. In this method the most fruitful investigations have been made by carrying out the reaction in situ at the temperature at which the film is actually protective. Literature The oxidation of iron has been extensively investigated by X-ray and electron diffraction. Jackson and Quarrelll found that oxide films formed and examined at the same temperature differed considerably from those allowed to cool to room temperature. The results showed that below 400°C the oxide that was stable in intimate contact with iron was Fe³O4; between 515° and 900°C. the stable film was FeO. Above the upper change point of iron the oxide was found to be Fe³O4. From 400' to 515°C., FeO, Fe³O4 or a mixture of the two oxides was found. Recrystallization of the air-formed film below 400' and above 900°C. led to the formation of Fe3O4. In the range where thicker films consisted of FeO, the air-formed film was converted to a new hexagonal oxide not previously described.

Jan 1, 1947

By J. J. Thomas, J. H. Nead

This investigation was undertaken to determine, if possible, the relation between static and dynamic tensile tests as measured by the work required to break test specimens slowly, in a tensile testing machine, and rapidly, by means of a falling weight. It was hoped that the investigation would throw some light on the role played by ductility under different rates of application of load. In problems of design, it is usually assumed that the moduli of elasticity of all steels are equal; viz., about 30,000,000. The stress-strain diagram within the elastic limit is a straight line, as shown in Fig. 1, where OA is the curve of a hard steel and OB that of a soft steel. If the modulus of elasticity is constant, as assumed, the slope of the line OC

Jan 1, 1922

By J. H. Nead, J. J. Thomas

This investigation was undertaken to determine, if possible, the relation between static and dynamic tensile tests as measured by the work required to break test specimens slowly, in a tensile testing machine, and rapidly, by means of a falling weight. It was hoped that the investigation would throw some light on the role played by ductility under different rates of application of load. In problems of design, it is usually assumed that the moduli of elasticity of all steels are equal; viz., about 30,000,000. The stress-strain diagram within the elastic limit is a straight line, as shown in Fig. 1, where OA is the curve of a hard steel and OB that of a soft steel. If the modulus of elasticity is constant, as assumed, the slope of the line OC

Jan 1, 1922

By R. Maddin, C. H. Mathewson, W. R. Hibbard

Recent publicationsl.2 establishing the presence of cross-slip in strained metallic single crystals oriented wholly within the area of single slip as predicted from the generalizations of Taylor and Elam3 described these markings as they appeared during the initial stages of the deformation process. At that time, the plane having a common glide direction with the primary slipping plane was reported as the cross-slip plane although the specific direction was not confirmed. Consequently, in continuation of the research, it seemed advisable to investigate the micro-graphic appearance of cross-slip together with the Laue back-reflection X ray analysis and stress-strain data during the later stages of the deformation process. Accordingly, a single crystal of brass (72.75 pct Cu, 0.01 pct Fe, 0.01 pct Pb, 27.23 pct Zn) was polished mechanically and repolished electrolytically after the manner described in the earlier paper.' Three pairs of flat surfaces, parallel to the specimen axis, and (1) perpendicular to the plane containing the pole of the primary glide plane and the specimen axis, (2) perpendicular to the plane containing the pole of the cross-slip plane and the specimen axis, and (3) perpendicular to the plane containing the slip direction and the specimen axis, were polished mechanically and repolished electrolytically, resulting in a final minimum gauge diameter of 0.4864 in. in a gauge length of 3.36 in. The specimen was elongated in tension and load-extension readings were taken following the method described in the initial investigation.' Observed reorientations were obtained from a series of Laue back-reflection photograms at the center and ends of the gauge length and at various positions around the circumference of the specimen. These were interpreted after the manner of A. B. Greninger.4 Cross-slip (Fig 1 and 2) was found with the first appearance of the primary slip clusters and usually joined members of these clusters. In addition, a third set of entirely different markings (Fig 3) could be noted. The displacement of this third set by the primary slip lines was measured as 8300 at. diam (3.04 microns). Since the specimen was carefully observed at high magnifications before any deformation and no markings of any type could be noted, it would appear that this third set was formed during the deformation process prior to the initiation of classical primary slip. Additional extensions produced no unusual change in the appearance of either cross-slip or the third set of markings. The number of lines increased with increasing elongation and appeared, generally, in areas where earlier markings were present. The continuity of the clusters of cross-slip lines in Fig 4, 5 and 6 illustrates that they are neither noticeably displaced by nor do they displace the primary lines at this stage. In Fig 7, cross-slip appears in a long narrow localized band approximately 45 degrees from the stress axis. This somewhat resembles a twin band except for the lack of a sharp boundary. After a shear of 0.257, suffcient additional glide occurred on the cross-slip plane to displace the primary slip lines (Fig 8). Generally, where a large number of cross-slip lines could be observed in an area on one flat surface, few cross-slip lines appeared on the diametrically opposite position on the parallel flat (Fig 9). These, of course, were not matched observations on the same glide ellipses. It was extremely difficult to make such comparisons. The third set of markings (Fig 10) was extensively displaced by glide on the primary slip planes. A plot of the width of primary slip clusters versus their displacement of the third set of lines is shown in Fig 11. The slope and the linearity of the plot suggest that each primary glide plane slips to a constant maximum value of shear before further slip is transferred to another plane. A shear value of 0.28 was determined in this case. Heidenreich5 has presented a similar schematic representation of glide for aluminum. After the specimen had attained an elongation of 51.8 pct, corresponding to a shear of 0.973, cross-slip appeared very prominently in certain areas as shown in Fig 12, yet at diametrically opposite positions very little cross-slip could be noted, Fig 13. Classical conjugate slip was found at this advanced stage in the deformation, Fig 14, which corresponds to the axial location shown at 12 in Fig 15. It should be noted that cross-slip occurs within the conjugate slip clusters and on the same plane as the cross-slip associated with the closely spaced primary lines which constitute a background in less distinct focus. The third set of markings noted at all stages in the deformation of the

Jan 1, 1950

By Lyman H. Hart

Some of the significant facts that will affect the supply and demand for metals during the next few decades are given in this presentation. This is important because the only hope for intelligent guidance of the national destiny depends upon presenting a consistent and accurate picture of basic problems. The metals problems now fomenting are only slightly less important than those precipitating the energy crisis. Admittedly, it is difficult to generate serious thinking on this subject when the world is enjoying easy access to all metals at modest prices. This is possible because of the current world capacity to over-produce, and United States credit standing, at least up to now, has permitted buying freely on world markets. Although both these vital conditions are subject to change, there is little doubt that if the U.S. financial house is kept in order, we can muddle along for a while on a generally expanding, metal-based economy. But should our credit standing be permitted to collapse, or should there be a tightening of world supplies of metals, the nation would immediately find itself in trouble. Unfortunately, clear signals indicate that both of these conditions are threatening. The metal age started many centuries ago, and with the exception of the noble metals, barely a dent was made in world reserves until the present century. Then, as a result of the pioneering ideas of D. C. Jackling and Paul Gemmel, and the willingness of the McNeals, Penroses and Guggenheims to back ideas with money, a virtual explosion of metal production was propagated throughout the world. It is important to examine the causes of this expansion to determine whether it is a trend that may be sustained or whether it is anomalous and therefore attributable to circumstances not likely to be repeated or continued. This period of plenty is a once only phenomenon. Vast metal resources have been sitting around here for eons, while the world was unaware of or unconcerned with their existence. But when population began to grow exponentially, and ways were discovered to use metals to develop machines to do the work of men and animals, the exploitation of raw materials increased at a staggering rate. And now the realization is dawning that minerals are a wasting asset and are beginning to present supply problems that should begin to be of concern. Two main factors have caused this condition; One is the population growth, and the other is the expanding demand for irreplaceable raw materials as nations become more developed. A group of systems analysts, at Massachusetts Institute of Technology in a book Limits of Growth, has warned that at present rates of population growth and resource consumption together with environmental constraints, a point will be reached within 100 years when the world population will become totally incapable of supporting itself. The authors conclude that this end result could be avoided if a planned equilibrium could be established at a lower rate of population growth and resource consumption. Fortunately, there is evidence that the population problem is moderating. The growth rate in the U.S. has decreased from 2.3% per year in 1900 to 1.1% in 1970. But, even at the lower rate, population will double in 70 years. The world rate is greater, and if it continues, world population will rise from 3.5 billion to nearly 10 billion in 50 years. All of these projections are questionable because the dangers of growing population are now being recognized. A marked decrease in growth rate has been noted in the more developed countries-in fact, it was zero in the U.S. in 1972. The other factor affecting consumption of raw materials is the increase in per capita use of most items as individuals become more affluent. Many economists believe that developing countries such as China and India represent a vast future potential market; but there are others, with whom the author agrees, who believe over-population tends to stagnate development. Nevertheless, it is a fact that vigorously developing societies increase consumption at a rate far above their population growth rate.

Jan 1, 1974

G. SHERBURNE LAGERS (written discussion*).-Mr. Kennedy's discussion1 of Mr. Matteson's paper takes the form of a criticism of my own comments2 on this paper. Mr. Kennedy is a respected authority on matters pertaining to the salt-dome oil fields, and his characterization of my "elaborate figures" as "worthless" is sufficiently candid and comprehensive to warrant a brief reply. My "voluminous figures" consisted simply of a rough estimate of the minimum quantity of salt in the Humble dome, and a calculation of the volume of sea water and of the volume of saturated brine which this salt would represent. Mr. Kennedy apparently interprets my remarks as opposing the idea that so large a volume of salt could have been deposited from sea water, for lie cites the area and thickness of European salt beds; but nothing was further from my intention. Given an arm of the sea, an arid climate, and evaporation under a hot sun, it is easy to conceive the formation: of almost any thickness of bedded salt. I cited the figures in connection with Harris' theory of the origin of salt domes, according to which the plugs were formed by the deposition of salt from ascending brine solutions, owing to the drop in temperature as they neared the surface. I pointed out the well-known fact that the solubility of salt is only slightly affected by temperature, and that a drop of 80° C. would cause the deposition of less than one-tenth of the salt in solution; hence that more than ten times the volume of salt actually forming the plug must have been involved. If ten times the salt actually in sight be computed in terms of brine and multiplied by 50 or 60 to take into account all of the known salt domes, the resulting figure is so enormous that I am not at all as sure as Mr. Kennedy seems to be that the porous stratified rocks of eastern Texas and western Louisiana could contain or furnish so great a volume of migratory brine.

Jan 8, 1918

By Norman Carmichael, John Kiddie

The problem of transportation in the Clifton-Morenci district of Arizona has been one of peculiar difficulty and consequently has been an important factor in the cost of mining and treating the ores produced. From the crude beginning made over 50 years ago, many changes have been necessary to keep pace with the increased output of copper. A heavy-duty haulage system has developed on the original 20-in. track gage to meet the existent metal-mine conditions. Topography The transportation difficulties of this district may be readily appreciated from the relief map shown in Fig. 1. The northern half of the district is high mountainous country and there is a general but irregular drop toward the southern part, where the country, although still rugged, is in reality a great sloping plain. This is cut by numerous ravines from which the waters, in the rainy season, discharge into the channel of the San Francisco River. A chasm, 1000 ft. deep, has been eroded through the center of the district by Chase Creek, which is flanked by high irregular mountain masses, notably Copper Mountain, American Mountain, Coronado Mountain, and Markeen Mountain. The latter rises 2300 ft. above the bed of the creek, The San Francisco River has also cut a deep channel, though it is somewhat broader than Chase Creek. Eagle Creek traverses the extreme southwest portion of the area, where it has carved picturesquely through vast volcanic flows. Faulting has left its mark upon the topography of the district by adding to the irregularities caused by erosion. Strong faults occur at the Coro-

Jan 1, 1924

By Theron Wasson

Michigan's production of 17,301,000 bbl. in 1945, which is in line with previous years, has been maintained by extensions to old fields like Deep River, Adams, Fork, and others. There were a number of new discoveries but, as in the past, these are not given very much importance because enough drilling has not been done to develop their potentialities; however, judging by the past, some of them will develop enough production so that 1946 -will probably be in line with other years. Activities in Michigan were confined to the Basin area of the lower Peninsula, which has been under development since 1925.

Jan 1, 1946

By Morris J. Elsing

FOR MANY YEARS lead and zinc have had the so-called protection of a tariff and it is the purpose of the following brief discussion to show what' such protection actually accomplishes with a view to forecasting the possible results of the present copper tariff. In analyzing the subject, tabulations of the United States production, consumption, imports and exports, including ore and concentrates and all of the metallic products, of both lead and zinc have been made for each year since 1900. Of these data, the relationship of the imports and exports and the relative foreign and domestic prices are shown in Table 1. The conclusions drawn from these figures are listed below. 1. The United States is an exporter of zinc. 2. The United States is an importer of lead. 3. The average price of zinc at St. Louis for the last 32 years has been no higher than on the London market even though zinc and zinc ore have "enjoyed" a protective (?) tariff of varying amounts per pound for 22 years of this period. 4. The average price of lead on the New York market for 32 years has been 1.2c. per pound higher than on the London market, the tariff varying from 0.75 to 1.5c. per pound of lead in ore, and 1 to 2c. or more on manufactured lead.

Jan 1, 1932

By R. U. Jackson

FACED with rising costs, the mining industry is looking to new methods and equipment to supply the relief necessary for profitable operation. Conveyor transportation is rapidly taking a superior position to motor tramming in underground mines because of lower installation, maintenance, and operating costs. Haulage is always a critical problem in underground mining. The ease of operation and flexibility of a haulage system can have an important effect on ultimate mining cost. With the average tenor of ores on the downgrade, larger tonnages are required for the same metal recovery. This selection of a tramming system can be the key to a successful, paying plant. Because this shift is being made at an ever advancing rate, it may become necessary to tailor mining operations to the transportation system, rather than to select a haulage system fitting set mining methods. In choosing a haulage system, the relative costs of the various methods are of the greatest importance. Adapting the mine to one or the other type of tramming is not considered in the cost analysis, and very likely would make little difference, outside of location of drifts and raises. In the cost sheet, the problem presents recommendations for a conveyor installation and a comparison of equipment, installation, operation, maintenance, and power costs are made. Under the track haulage estimate, no allowance was made for dumping equipment at the shaft pocket or bin. If this equipment was added to the balance sheet, the additional

Jan 1, 1952

By Otis W. Freeman

Production of oil in Indiana during 1944 is estimated at approximately 4,950,000 bbl., a decline of 6 per cent from the preceding year. Shortage of labor and material, together with governmental regulations resulting from the war, largely account for the drop in output and limited new developments. Three new pools were discovered in the state during 1944. Two of these, New Harmony, South, and Hovey, West, are in Posey County. Six wells in the New Harmony, South, field produced 66,422 bbl. of oil last year. A third field, Cato, in Pike County, did not market the oil from its discovery well during 1944. Several wells discovered oil in the Henderson field of Jay County along the Ohio state line. An important south extension of the St. Thomas field in Knox County was discovered during the year. Active drilling took place in the Inman, East, and Upton fields, Posey County, both discovered in 1943. Twenty-two wells in Inman, East, produced 151,1gr bbl. in 1944 and 12 in Upton produced 107,052 bbl. Owensville, and especially Owensville, North, in Gibson County, made large gains in production as a result of active drilling. The Dodds Bridge field in Sullivan County continued good production from deep sands reached in 1942. The Griffin continued to be the largest producer among the oil pools of Indiana, accounting for 2,004,180 bbl., over 40 per cent of the state's output. The next largest producing fields are Mt. Vernon and New Harmony, both in Posey County. The largest gas well brought in during 1944 was in the Rockport field, Spencer County, and had an initial output of 2,680,000 cu. ft. per day. The most productive gas fields in Indiana are Rockport, Spencer County, Greensburg, Decatur County, and Unionville, Monroe County. Total production in the state is . hard to estimate, as considerable gas is consumcd in farm homes and for other local uses, and never is reported, but was near 1500 million cubic feet. Some oil from the Trenton field is also used locally and is unreported from pipe-line runs. A total of 606,145 ft. of new hole was drilled in Indiana in 1944. Most of the completions were in Posey and Gibson counties, although wells were drilled in 36 different counties. During the year 331 wells were completed. Of these, 145 found oil in commercial quantities and 28 were gas wells. The initial production of the 145 oil wells was 11,908 bbl. per day. Settled production would be less, of course. The largest wells reported during the year were two on the J. W. Mann farm, in the Mt. Vernon field, with a flush flow of 500 to 800 bbl. each.. Six pools, all small "one well" affairs, were abandoned in 1944; i.e., Fleenor and Patoka in Gibson County, Grafton and Rapture in Posey County, Vaughn in Vandei-bwgh County and Millersburgh, Warrick County.

Jan 1, 1945

By J. J. Crowe, G. K. Burgess

PAGE, Theories of Allotropy of Iron........... 667 Previous Determinations of A2 and A3 in Iron........ 668 Critical Ranges as Determined by Expansion........ 669 Critical Ranges by Thermoelectric Observations........ Critical Ranges in Terms of Crystalline Structure....... 670 Critical Ranges as Detected by Mechanical Methods...... 670 Critical Ranges as Given by Electrical Resistance....... 670 Critical Ranges as Determined Magnetically........ 671 Critical Ranges as Determined Calorimetrically....... 673 Critical Ranges from Heating and Cooling Curves....... 673 Summary of Previous Determinations of A3 and A2 in Pure Iron.... 675 The Present Investigation............ 678 The Experimental Method........... 678 Arrangement of the Apparatus.......... 679 The Measurements of Temperaturc.......... 679 The Measurement of Time........... 679 The Thermocouples............ 681 Temperature Scale and Calibration of Thermocouples...... 681 Mounting of Thermocouples........... 682 The Differential Measurements.......... 682 The Furnace and Accessories........... 682 The Vacuum Pump............ 683 The Energy Supply............683 The Rheostat.............. 683 The Materials Investigated............ 685 Sources of Iron............. 685 Preparation and Description of Samples......... 685 Chemical Analyses............. 687 The Experimental Data............. 688 The Preliminary Observations.......... 688 The Definite Series............691 Description of the Plotted Curves........... 694 The Effect of Plotting at Different Intervals........ 694 The Curves of the Definite Series.......... 695 . The Curves of the Preliminary Series......... The Existence of Other Critical Ranges......... 696 The Microscopical Examination........... 697 Summary and Conclusions............ 698 Bibliography............... 701 Plates................ 704

Jan 1, 1914