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By Foster Bain

THOUGHTFUL people have raised questions as to how long nature's bank could continue to accept our drafts. These questions came to the fore so persistently, and there were so many evidences -such as the failure of natural gas in Indiana, the increasing scarcity of lumber in the Lake Superior region, the progressive sterility of Southern farm lands, the choking of the Sacramento River by tailing-point-ing to possible danger from overdraft or to misuse of resources and opportunity, that President Roosevelt called a conference which assembled at the White House on May 13, 1908, to consider these and related questions. This, the first great Conservation Congress, had a wide and beneficial influence on the thought of the world. It profoundly influenced the course of succeed-ing events and, while even yet there are sharp dis-agreements as, to the wisdom of much that has been done in the name of conservation, I believe that thoughtful men, and engineers especially, agree that the time had come when sharp attention was properly called to the waste that accompanied development of our resources. RESOURCES LARGE BUT NOT INEXHAUSTIBLE In 1908 there was a surprisingly large number of men, who should have known better, prepared to argue that our resources are "inexhaustible." No competent mining engineer, of course, believes that, as regards minerals at least. They may be, and, in most cases, fortunately are, large; as to many of them our knowledge is too general to permit measuring the reserves; but we know now, and I think the public appreciates, that there is a limit to our supply of gas, oil, coal, iron, and metals. Indeed, with the inten-sive study made necessary to meet the demands of the war, and the more careful accounting required by the newer systems of taxation, depletion has become a common word, and that mines are wasting assets has become a platitude.

Jan 8, 1922

By A. G. Moncrieff

In the paper the authors show [(Fig. 12)] in diagramatic form a "typical vacuum filtration system." This indicates a drum filter with two filtrate receivers-one for mother liquor and one for wash liquor. Have the authors ever found a drum filter that will adequately separate mother liquor from wash liquor? I recall in about 1957 being superintendent of a major copper leaching operation treating oxide flotation concentrates. The plan was being expanded, and filters installed to replace CCD following acid leaching and primary thickening of the pulp. The design of the expansion allowed the mother liquor to join the thickener overflow as feed for the electrolytic tankhouse. The water balance required that only pan of the wash liquor could be electrolysed direct, and the remainder had to be treated by lime precipitation. The design assumed the mother liquor would have the same copper content (about 50 gpl) as in the leach pulp solution, and the wash liquor about 50% of this (25 gpl from memory). You can imagine my horror when, on starting up, the solution from the mother liquor receiver contained somewhat under 40 gpl and, from the wash liquor receiver, somewhat over 40 gpl. The filters were provided by two of the most reputable manufacturers and, in the end I believe they agreed that never before had they supplied rotary drum filters that would segregate the filtrates. By changes to the valve design we made minor improvements, but eventually decided that insufficient segregation of the filtrates was possible to warrant trying to do it. On further consideration I concluded that, owing to the time delay between solution passing through the cake and entering the valve, segregation was impossible, though radical alteration of the internal piping of the filter might have improved it. I would be interested to know if anyone has found a solution to this problem using a drum filter. If not, why go on publishing information that infers that it is possible?

Jan 1, 1982

By W. S. Ayres

[Secretary's Note.—At the Spokane meeting of the Institute, in discussion of President Brunton's address on "Modern Progress in Mining and Metallurgy in the Western United States," and at the request of members present, Mr. Ayres gave an oral account of his new separator, which is here published as an independent paper, partly because of its inherent importance and partly because it describes an improvement which did not originate in the Western United States, and therefore does not fall, strictly speaking, under the title of President Urunton's address.—R. W. R.] A brief history of the growth of the anthracite-coal preparation will give a better view-point from which to judge the present problem of separating slate from coal. At the beginning of the commercial value of anthracite, 70 years ago, only the pure portions, or " splits," of the veins were mined and shipped to market, and without any preparation or screening other than the selection, while loading, of the glassy lumps, and the rejection of the fine material and the slate that had strayed accidentally into the coal. The next step was the crushing or breaking of the coal (hence the name "breaker" as applied to the preparation-building), and the sizing of it by means of bars or revolving screens. This stage of its development marked the advent of the " breaker-boy " as a slate-picker, with his ever-increasing capriciousness. As the richer veins or a splits " became exhausted and the market demanded a still greater output, the less-pure " splits " and the thinner veins were utilized to produce the coal. Carrying as they do a far greater percentage of impurities, particularly when removing the pillars, it became necessary to build new and better equipped preparation-plants. Finally, we are now at the highest stage of complicatioii yet known to the art of coal-preparation. We are dealing with varying specific gravities, frictional difference, hardness, structure, and form in the pieces of coal and slate coming from many different veins, and

Jan 1, 1910

By J. B. Umpleby

PRoduction engineering in 1927 may be characterized by a great. clarification of fundamental conceptions, and many improvements in technique. During the year the profession has received tnarked recogni-tion by the industry and to an extent never before attained has become an integral part of it. History Petroleum production engineering is a new profession. Prior to 1925, when this Institute undertook the work, no forum existed for the open discussion of its technical problems. There was no attempt at a handbook of the subject prior to "Petroleum Production Methods by J. R. Suman, in 1921, and no textbook prior to Petroleum Production Engineering" by L. C. Uren, in 1924. As late as 1926, only six schools and universities offered special courses in petroleum production engineering. Prior to about 1923, engineers engaged by oil companies were used almost exclusively for construction and location work. Two of the leading production engineers in the Mid-Continent field, although with their respective companies more than twelve years, were not definitely assigned to production work until 1924. Both men now head large departments giving almost their entire time to production problems. Because of the newness of the profession, the leading production engineers of today have had their fundamental training in mining, civil, mechanical and electrical courses. Not unlikely this diversified training is in considerable part responsible for the amazing growth of the profession. I believe, however, that recognition is due principally to economic pressure within the industry which has directed attention more and more sharply on costs and efficiency. After all, the justification for the growth and continued development, of the profession is to recover more oil from a given unit of sand at less cost per barrel. In this new profession, it seems to me that greatest progress will result from focusing thought and effort on this single objective, and if I might offer one suggestion to the com-

Jan 1, 1928

By Alan Morris

THE investigation of the hot-working properties of metals and alloys furnishes a problem which has been attacked in many ways. Tensile, impact and hardness tests on heated specimens have furnished interesting data, but in most cases either the tests are difficult to make or the results hard to translate into terms of practical value. Some investigators have used the drop hammer to advantage. It furnishes a rapid and simple method of comparing the plasticity of metals at elevated temperatures. The indications obtained by its use are of value only in so far as their significance is understood and they can be intelligently used to predict the behavior of a given metal under given hot-working conditions. The work reported here was undertaken not only to add-something to the existing volume of such data but also to contribute to our understanding of the results. Doerinckel and Trockels1 used cylindrical specimens and determined the work required to reduce the specimen to one-half the original height. Ellis2 studied the effect of constitution on the malleability of steel at high temperature. His method and that of Kent3 were similar to the one used in the present work. The tests described by Kent were made on samples of tin, zinc, aluminum, copper, lead, 70:30 and 60:40 brasses, with and without a small quantity of lead. He concluded that the test would "indicate whether a material can be forged at a given temperature without cracking." This interpretation must be used with caution. While it is probably true within limits, one must consider the severity of the forging operation. Again, it will not apply strictly to forms of hot working other than forging. For instance, an alloy running 61.0 per cent. copper, 3.25 per cent. lead, remainder zinc, will crack badly in the test, yet it is extruded commercially. When the possibility of hot-working a new alloy is being considered a study of its drop-hammer test should help

Jan 1, 1931

By H. C. Kenny

The annealing or softening temperature of cold-worked copper is appreciably increased by almost unbelievably small amounts of silver. As indicated by some data in this paper, the softening temperature of high-conductivity, tough-pitch copper may be increased from 200" to 350" C. by the addition of only 15 oz. per ton (0.052 per cent) of that element. Because it has this higher annealing temperature as compared with the silver-free metal, silver-bearing copper finds considerable use in industry. For example, when hard-rolled copper is used in operations that involve soldering or tinning, silver-bearing copper insures against loss of strength, whereas silver-free copper becomes "dead soft." Yet—though several investigators, beginning with Caesar and Gernerl in 1916, have shown that small amounts of silver do definitely raise the softening temperature of copper—data are lacking on the problem: What is the specific influence of different amounts of silver on this temperature? It was to help in filling this gap in the knowledge of what might be termed "alloy coppers" that the data given herein were obtained. The softening of cold-worked copper depends, of course, on a number of factors, of which the composition of the material is only one. Other highly important factors are the degree to which the material is cold-worked and the time it is held at the annealing temperature. The method of cold working and the grain size of the metal produced are also significant. All these variables were taken into account in the investigation reported here, and the influence of silver on the electrical conductivity and on the working was also considered. The coppers used in the softening tests were Lake coppers melted and cast by the Calumet and Hecla Consolidated Copper Co. The ires were fabricated by the Roebling Wire Co. and the sheets were rolled at the Battelle Memorial Institute. Partial analyses of some of the coppers are listed in Table 1, with their electrical conductivities.

Jan 1, 1934

By Lewis W. MacNaughton

The North Texas district, as herein defined, includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Knox, Montague, Wichita, and Wilbarger. This area covers generally the crest and south flank of a system of buried mountains known as the Red River uplift. The oil and gas accumulations along this feature arc in traps, which, although localized by structures incident to the regional uplift, are usually modified by stratigraphic changes in the sediments. Excepting the fields in southeastern Baylor, southern Archer, and southwestern Clay counties, all the fields within the district are on this Red River uplift. These exceptions, which have the same type of oil and gas accumulation as the other fields, are on the extreme north end of the Bend arch, which is a broad anticline plunging northward from the Llano uplift in central Texas to Archer County. The larger part of past oil and gas production has come from Pennsylvanian strata, with less important amounts from the Permian, and minor but increasingly important quantities from the Ordovician. Developments during 1939 With the later stages of development being reached in the K.M.A. field during the first half of the year, some 400 fewer producing wells were drilled in North Texas in 1939 than in 1938, when some 1750 wells were drilled. Despite this decrease in activity, production in 1939 increased about 3½ million barrels over 1938 figures, and at the end of the year the oil reserves were somewhat larger than on the first of the year. As is usually characteristic of the district, this resulted from the discovery of a large number of relatively unimportant fields. Owing principally to no appreciable abatement in wildcat drilling, more new fields and extensions to old fields were discovered this year. Although none of these discoveries was of such magnitude as to be important to the oil industry, the new developments in Montague and Cooke Counties portend greater and probably more important operations in these areas.

Jan 1, 1940

By J. Elmer Thomas

The evolution of the oil business is one of the great industrial romances of modern times. First used as a medicine, then as a lubricant, then as an illuminant, and finally as a motor fuel, each change in its principal usage caused large increases in consumption. Producing Successes The producing branch of the industry responded ably to the demands made upon it. Never was there a famine, rarely any threat of scarcity, and stored inventories were gradually accumulated to form comfortable working stocks. Originally an erratic and hazardous undertaking, the discovery and development of oil fields has made such strides as to classify now as a science. When storage stocks were low, production in close balance with consumption, and demand trending sharply upward, considerable concern was expressed over future needs. Price was very responsive to fluctuations in supply under those conditions, and quotations for crude and refined oils exhibited wide swings. A very different situation exists today. Consideration of the statistics only since the war will show how recent has been this change. In the 10-year period from 1918 to 1927 inclusive, we produced in the United States 6,100,000,000 bbl. of crude and imported 900,000,000 bbl., our total supply being 7,000,000,000 bbl. The consumption was 6,600,000,000 bbl., thus adding to stocks 400,000,000 bbl., an accumulation of somewhat less than 6 per cent. of the total supply. During that period virtually every field was promptly developed as soon as discovered and nearly every well in the country was producing at full capacity. With the maximum production of the wells required to take care of the rapid increases in consumption, with storage stocks moderate and proven reserves very slight, the producing division of the industry acquired a tempo not needed now. Potential Surplus Today the situation is vastly different. The economic consumption is about 2,700,000 bbl., with current production slightly in excess of that.

Jan 1, 1930

By H. Scott

IN a paper read before the Institute of Metals, Rosenhain 1 described a new type of furnace designed primarily for the thermal analysis of metals by the inverse-rate method and used by him in the metallurgical department of the National Physical Laboratory with considerable success. In his discussion of this furnace, Rosenhain pointed out some difficulties met with in its operation, such as uniformity of rate of heating or cooling being inadequate for the degree of accuracy aimed at. To overcome this difficulty, he suggested, in place of motor propulsion, a gravity drive controlled by a"hydraulic cylinder with a relief valve whose width of opening can he regulated to allow of any desired rate of motion." The authors, in constructing a thermal-analysis furnace of Rosenhain's type, have therefore followed this suggestion and also added certain features that increase somewhat the convenience and simplicity of its operation. Requests for information regarding this furnace and the highly satisfactory results obtained from its use, it is believed, justify describing its construction and operation in sufficient detail to make possible its duplication or improvement. Description of Furnace.-The details of the furnace construction are shown in Fig. 1, which is drawn to scale. The heating tube is of /4 in. (6.35 mm.) wall "alundum" heated at the upper end by seventeen turns of 0.52 mm. platinum wire, which is coated with "alundum" cement supplied for this purpose. The cement coating is essential when a high temperature (over 1000° C.) is required, as it prevents hot spots with the resulting burning out of the heater. This platinum-wire winding, unlike "nichrome," is entirely satisfactory for temperatures of at least 1000° C. It has been maintained at that temperature continuously for 2 months and shows no signs of deterioration. This temperature is maintained by a current of 5 amp. drawn from 30 volts potential, so its necessarily continuous operation is quite economical.

Jan 8, 1919

By B. M. Harra, R. L. Hallows, O&apos

The term "modern automatic baghouses" as used in the title of this paper is intended to designate a general type of mechanical fume filter, introduced some 20 years ago and gradually improved since that time. It is characterized by its small filtering bags, enclosed in groups of 15 to 30 in steel compartments, and by its frequency of shaking, as compared to the old type of baghouse, which uses much larger bags, shaken at much longer intervals. Automatic baghouses are produced by a number of well-known manufacturers. Some recently constructed baghouses of the old type have embodied some of the principles of the automatic type, in that they are divided into several compartments, with separate fans for the different compartments, and flue headers arranged so that when the fan to any one compartment is shut down preparatory to shaking the bags in that compartment, the bags are put under suction by the draft from the other fans, thus making possible more efficient cleaning of the bags. These baghouses have motor-driven shaking mechanisms, and generally are operated under higher pressure and shaken at more frequent intervals than was the practice with the old style baghouse, and consequently have greater filtering capacity per unit of bag area. It is possible to interconnect the fan motors and the motors driving the bag-shaking mechanism, with suitable relays and timing devices, so that the operation of this type of baghouse also becomes to a considerable extent automatic. These baghouses are intermediate between the old style of baghouses, strictly speaking, and the completely automatic baghouses. They may he considered just as modern as the latter, and their proponents can no doubt cite many advantages for them. The authors are less familiar with them than with other types, and the following discussion will be limited to a comparison of the automatic baghouses and old style baghouses, with particular reference to the experience of The Eagle-Picher Lead Co. and The Eagle-Picher Mining and Smelting Company.

Jan 1, 1937

By Robert S. Shoemaker

At this Symposium on Gold which is sponsored by The Metallurgical Society of AIME and the International Precious Metals Institute many distinguished authors will present the latest developments in the metallurgy of gold and in operating practices at mines and in refineries. It seems appropriate then, as the introduction to this volume to recall some of the history of gold and the metallurgical developments which have been accomplished, especially during the past 100 years and some of the people who have contributed so much to the metallurgy of gold. Of all the elements gold has been the most sought after since the earliest times. Perhaps the quotation from Virgil's Aeneid best describes man's desire for gold but Pliny the Elder also put it very well when he wrote in 79 A.D. that "Gold is the first of man's follies, silver the second". This quest for gold has markedly influenced man's history and through the efforts of the early philosophers and alchemists to turn base metals into gold the foundations for modern chemistry were laid. The pages of history literally teem with references to gold. Gold is the first metal mentioned in the Bible and was the source of Croesus wealth as well as the death of King Midas whose touch turned everything into gold. And of course almost everyone has heard of Jason's Argonauts and the golden fleece. They are the subject of one of the many drawings in Agricola's De Re Metallica published in 1556. The Argonauts were probably prospectors seeking the source of the placers in the region near-the Black Sea. The time was about 1200 B.C. and the placer miners recovered gold by trapping the particles in sheep's fleeces placed in sluices. After drying, the fleeces were shaken to recover the gold. Gold is not hydrophilic, or wetted by water and thus the oils in the wool aided in collecting the particles. Here we have perhaps the earliest reference to surface chemistry and the basis for concentration of gold by flotation.

Jan 1, 1984

By C. G. McLachlan

ONE phase of the treatment in sulphide flotation, covered generally in a review of pulp pretreat-ment by S. A. Falconer,' is the matter of grinding mills as conditioners, a subject on which further study could be advantageous. Flotation with few exceptions is preceded by grinding, and the grinding and flotation capacity required for the treatment of an ore is based generally on laboratory or pilot mill tests. The results of such tests, it then is assumed, will be duplicated in practice, and a flowsheet is prepared on that basis. This assumption may be too broad, because in several instances laboratory flotation tests made on massive sulphide copper ores could not be duplicated in plant operation without the introduction of an aeration step, either in closed circuit with the grind-inging mills, or between grinding and flotation.~' " The differences between laboratory and plant grinding practice are considerable, and may be summarized as follows: 1—In the laboratory a relatively fine charge is ground in a batch mill. In the plant, the feed, usually considerably coarser than the ore tested in the laboratory, enters the grinding mill continuously and more often than not, oversize material in the mill discharge is retained in the grinding circuit by a classifier until the required degree of reduction has been effected. 2—The rate of grinding in the laboratory is slower than in plant practice. 3—The percentage of volume occupied by the pulp in a laboratory mill rarely approaches that of a continuous overflow type mill. This does not apply if the comparison is made with grate type mills, but in that case an even wider discrepancy between the relative rates of laboratory and mill grinding almost invariably exists. The present trend in grinding is toward larger mills to reduce the number of operating units. This accentuates the foregoing differences. It is believed that the trend toward larger mills is sound, but that when large mills are used, metallurgists should check their flotation circuits carefully to determine whether laboratory tests are being reproduced in

Jan 1, 1952

By Roswell Johnson

WHAT becomes of the water which must have filled the oil and gas sands at the time of deposition, has long puzzled students of oil and gas and has found expression in Munn's well known article on the hydraulic theory. Both Munn and Clapp have pointed out that in the Appalachian field the deeper sands carry increasingly less proportionate amounts of water. It seems to me probable that the principal source of oil and gas has been in the shales in proximity to the sands which now contain these products. The sand spits which mark off the lagoons from the sea comply particularly with the requirements of a limited sand imbedded in shales rich in organic matter. Cunningham Craig has objected to this view that the rich organic muds of lagoons are found only at the surface. That such muds do extend to considerable depth 1 am assured by Prof. Douglas W. Johnson, who has made an extensive study of the Atlantic Coast marshes. As any particular sand body becomes weighted by a heavier and heavier overburden, the result of increasing deposition, a part of the very large percentage of water in the uncompacted sand and mud is forced pout. The water percentage of freshly settled mud is vastly higher than that of the resultant shales, or even of a very porous sand. If beds of less compressible material meet or underlie the shales in question, there will. frequently be a lateral motion along such beds to some point where the upward movement will be resumed. We find in our laboratory work here that oil, gas, and water have extremely slight capacity for gravitational sorting while in a state of rest but when moving the gravitational sorting is readily accomplished. As the oil, gas, and water pass a body of larger pores, the gas, owing to its lack of capillary attraction, is retained in .the large pores.

Jan 2, 1915

By C. M. Young

WHEREVER salt is extracted from the ground as an artificial brine produced by pumping down fresh water to dissolve the salt, subsidence of the overburden is a possibility, though apparently few cases of such subsidence have been noted and detailed records are wanting. This description is intended as a record of subsidence that may permit the forcasting of similar occurrences in other cases; the data were supplied largely by R. B. Lee, city engineer of Hutchinson, Kans. About eleven years ago, ground movement occurred at a neighboring salt plant, when the surface assumed the form of a shallow funnel. Movement was probably due to a flow of sand into a well through a poor seal or a broken casing. The salt deposit increases in thickness from the east until at Hutchinson, where the subsidence occurred, it is about 310 ft. think. The interbedded layers of shale vary in thickness from mere traces to about 7 ft. While knowledge of the shale content of the beds is not exact, the log of a shaft 3 miles east of Hutchinson indicates that shale forms about 25 per cent. of the total thickness. This shaft does not reach the bottom of the salt by about 60 ft., but there is no reason to think that the lower part of the bed is different from the upper. Logs of wells sunk to the bottom are not sufficiently detailed to be of much value. Above the salt is the shale of the well-known Red Beds. The thickness of this is variable, principally because of its eroded surface, but at the mine it is 340 ft. This shale is variable in character and strength, but contains no strong members of limestone or sandstone. If the support is removed, very probably it will subside. The Arkansas River flows across the salt district and Hutchinson is situated on the flood plain. Between the top soil, which is about 8 ft. thick, and the shale is 60 to 100 ft. of water-bearing sand and gravel.

Jan 2, 1926

By H. R. Shidel

THIS paper summarizes the results obtained from the preliminary cementing of wells in an effort to cut off the bottom water. The object of this work was two-fold: (1) To prevent the oil sand from becoming flooded. (2) To plug off bottom water, thereby preserving the individual well and reclaiming production. Valuable suggestions and help have been given by the following named: Messrs. Kyle and La Velle, of the U. S. Bureau of Mines; Magnolia Petroleum Co.; Freed Oil and Gas Co. The cementing work was carried out under the personal supervision of L. J. Snyder. In an unpublished paper on the "Water Problem in the Augusta Field," S. K. Clark reaches the following conclusions: (1) That the great amount of water present is bottom water, occurring in the Varner sand, the main producing or the 2500-ft. horizon. (2) That the only striking connection between structure and water is in the area of the marked fault on the Ralston, E. C. Varner, and F. Varner leases in sections 8, 9, 16 and 17. (3) That the oil occurs in porous streaks, generally separated by fine-grained, well cemented sand, which is barren. Possibly two, or three such pay streaks may be found. That under a pay, fine-grained sand occurs, which is presumably barren at the time of drilling, but soon reveals water. The writer takes partial exception to the last point, because well defined shale, slate, lime, or hard sand breaks have been encountered in a great many cases, separating the pay streaks under which water is often found. This is not an invariable occurrence, as cases have been noted when the oil has been followed immediately by water in the same stratum. In an effort to overcome the water menace, the following methods of plugging were tried: (1) Plugging with wood, lead, and limit plugs. (2) Plugging with sand pumpings.

Jan 10, 1918

By R. R. Wilson

THE Cassidy Colliery operated by the Granby Consolidated Mining, Smelting & Power Co., Ltd., is situated about 9 miles in a southerly direction from the city of Nanaimo on Vancouver Island. The coal seam worked, which is called the Douglas bed, outcrops in the western part of the property, clipping easteyrl, and is opened by a slope 7 by 14 ft. in the clear, and is timbered by 12 to 14-in. framed sets of timber, 4 ft. center to center. A separate manway provides for a traveling road and at the same time forms an intake airway. The general average of the dip of the seam at Cassidy is 18°, and varies in thickness from 1 to 25 ft., averaging about 8 ft. The main slopes follow straight down the dip a distance of 4545 ft. At the bottom of the main slope two rock tunnels were driven a distance of 1500 ft. to the south, cutting through a fault, and opening up an area in the same seam which is known as No. 7 South Section. The coal is found in this section at a vertical depth of 1560 ft., and is very soft and friable. The immediate roof is a strong, sandy shale overlain by massive sandstone while the floor is a light-colored shale, hard when freshly exposed. It does not soften materially oil exposure. In the folding of the coal measures a great thrust caused a movement along the coal seam as indicated by the slickensided nature of the coal. The floor has buckled and this has rolled and squeezed the coal-so that with rare exceptions it shows no normal bedding but curved slip planes, which frequently start at right angles to the floor, curving upward and then in the direction of the dip. As such planes are slickensided it is probable that there is a coating of clay which is more or less impervious to gas.

Jan 1, 1927

By Edward W. Parker

At the Cleveland meeting of the Institute, October, 1912, I had occasion to call attention to the general though erroneous impression that the principal mining activities of the United States lie west of the 100th meridian of longitude. Few, I believe, realize that the States east of the Mississippi river, which comprise only 28.8 per cent. of the total area of the United States, exclusive of Alaska, contribute about two-thirds of the total mineral production, computing by values. In 1910 the percentage of the production credited to the Eastern States was 67; in 1911 it was 65. When I have, with becoming modesty, ventured to speak of these comparisons, I have usually been met with the rejoinder, " But you include coal." I surely do, for whereas coal (m petroleum, as natural gas, as limestone) is not in the strictly technical definition of the word, a " mineral," it is legally mineral, is certainly a mineral substance, and contributes by far the largest tonnage and approximately one-third of the total value of all mineral products. The production of coal-mines in 1911 weighed approximately 500,000,000 tons. In 1912 it exceeded that record by nearly, if not quite, 50,000,000 tons. According to H. D. McCaskey, of the U. S. Geological Survey, the total weight of all the metallic ores mined in the United States in 1911 was 105,000,000 tons (a little more than one-fifth that of coal). In 1910 Mr. Lindgren estimated the total weight of all metallic ores at 120,000,000 tons. The products of the quarries, clay-pits, oil-wells, phosphate-mines, and other non-metallic products, taken all together, did not in 1911 weigh in excess of 300,000,000 tons, so that the output of coal exceeds by 25 per cent. the combined tonnage of all other mineral products. The coal-mines give to

Jan 1, 1914

By Junius D. Edwards, Cyril S. Taylor

Magnesium is the lightest metal used for structural purposes, for which reason perhaps more than usual interest is attached to measurements of its density. Although the density of solid magnesium has been det,ermined frequently, no measurements of the density of the liquid metal are available. Because of unusual experimental difficulties in measuring the density of the liquid, only a limited number of measurements of good precision were secured. The results, especially the value for the crystallization shrinkage, are of great interest in connection with the casting of the metal. A number of samples for these measurements were made available through the courtesy of the American Magnesium Corp. They were in the form of extruded bars 3/8 in- in diameter and several were of exceptional purity, as indicated by careful analyses. Table 1 gives the density values (at 20" C.) for magnesium of varying degrees of purity. The density was measured at room temperature by comparison of the weight in air, and when immersed in distilled water. The necessary buoyancy corrections were applied, so that the density could be expressed in absolute measure—grams per milliliter. The effect of the buoyancy of the immersed suspension and the surface-tension pull of the water upon the suspension were eliminated from the results by a preliminary weighing of the suspension immersed to the working depth. Great care was necessary to prevent the introduction of a significant error by the formation of gas bubbles upon the clean magnesium surfaces; these are sometimes very minute and easily escape observation. They may be detached by raising the specimen from the water and again immersing; this should be done just prior to completing the weighing. Their formation may be almost entirely prevented during a measurement by previously immersing the specimen in a solution of paraffin in petroleum ether. The thin film of paraffin remaining after the evaporation of the solvent prevents wetting of the magnesium surface by the water. In one such determination, the paraffin coating on a 22-gm. Specimen

Jan 1, 1923

By Norman Maxwell

There was more activity in crude production in northwestern Pennsylvania in 1935 than for several years before, resulting in an increased oil production and also in the number of wells completed. Crude -production approximated 16 million barrels for the state, an increase of about one million barrels over 1934. Demand, indicated by refiners' runs to stills, increased proportionally, leaving stocks of available crude at the end of the year at the lowest point since the middle of 1934, when they reached an all-time low. The price of crude varied during the year from a low of $2.02 to a high of $2.27 at the end of the year for Middle district oil. The price of Bradford and southwest Pcnnsylvania oil changed accordingly. The average for the year would be a lower price than in 1934. A summary of the production data for the year 1935 is given in Table 1. In making up this table, 1935 figures were simply added to the table published by S. H. Cathcart last year1. A list of important wildcats is given in Table 2. Bradford Field Approximately 10,000 acres of the proven producing area of the Bradford field is in Cattaraugus County, New York, and it is possible, by differences, to distinguish the Pennsylvania production from the New York portion. The listed production for the Bradford field includes only that portion of the field situated in Pennsylvania, but also includes production from a small pool, locally known as the Mt. Jewett-Kanesholm pool, where the Bradford sand is being developed and flooded in precisply the same manner as that of the Bradford field itself. The Mt. Jewett-Kanesholm pool is not, strictly speaking, an extension of the Bradford field, but inasmuch as it is so closely allied with the Bradford field-—that is, the sand is the same and the production methods are the same—the production and drilling figures include this area.

Jan 1, 1936

By Shun-ichi Satoh

In the previous paper, the writer indicated that the arc welding of cast iron is practicable only when barium carbonate is used to retard the fusion of electrodes. Later, he tested the effects of 48 other elements, to discover the cause of their retarding action. Wrought-iron bars 33 cm. long and 0.53 cm. dia. were used as electrodes. The chemical analysis of the original electrode is given in Table 1. Table 1.—Analysis of Electrode Per Cent. Carbon.................................................. 0.045 Silicon................................................... 0.028 Manganese....................................... Trace Phosphorus.............................................. 0.047 Sulfur................................................... 0.008 Each of the bars was wound with a twine of asbestos (1 mm. dia., weighing 0.5 g.) and then was coated with a mixture of equal quantities of graphite and carborundum and one of the compounds listed in the second column of Table 2. The method used in coating was as follows: The mixtures were reduced to paste by adding to them a solution of water glass (1:3); they were next put in a glass tube of 8 mm. inner diameter, with funnel-shaped mouth (the same tube shown in the previous paper); then the bars were passed through the tube so that the mixtures were coated on them. The glass tube was used only as a means of making the diameters of all coated bars exactly 8 millimeters. The cast iron was deposited on the steel plates by connecting the electrodes first to the positive and then to the negative pole of the generator. The figures representing the time, voltage, amperes and energy required to melt each electrode are given in Table 2. They are arranged in the order of the atomic weights of the elements contained in the coatings. In Figs. 1 to 4, which show respectively the time, current, voltage and energy required in this operation, the abscissas indicate the atomic weights of the elements contained in the coatings, and the ordinates

Jan 1, 1929