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By J. D. Mote, J. E. Dorn

This investigation was undertaken to study the effects of piledup arrays of dislocations on inducing slip, twinning, and fracturing in magnesium bicrystals. A series of variously oriented bicrystals of magnesium having a vertical grain boundary were prepared and tested in tension. It was found that piled-up arrays of dislocations at the grain boundary could, under appropriate conditions, induce slip, twinning- and cracking. The results that were obtained substantiate, at least qualitatively, the general dislocation mechanism for transmission of strain across grain boundaries and the Petch-Stroh concept of fracturing. WHEREAS single crystals of magnesium generally exhibit extensive deformation, coarse-grained poly-crystalline magnesium at subatmospheric temperatures fractures after a few percent elongation.' Although a small amount of ductility is obtained, several features of this fracturing are characteristic of typical brittle behavior. Over a rather broad temperature range the fracture stress is insensitive to the test temperature and the fracture stress increases linearly with the reciprocal of the square root of the mean grain diameter. The course of fracturing is predominantly intergranular, but small fragments of adjacent grains frequently adhere to the fractured surface.2 The brittle behavior of polycrystalline magnesium is attributable to the limited number of facile deformation mechanisms it exhibits at low temperatures. For a general deformation of a randomly oriented polycrystalline aggregate, each grain must exhibit at least five independent mechanisms of deformation to permit accommodation of the imposed deformation from grain to grain.= Although minor amounts of prismatic slip occur in corners of grains where stress concentrations are known to be high, glide in polycrystalline magnesium at low temperatures takes place almost exclusively by basal slip.' The common type of twinning, which takes place on the (1012) pyramidal planes, can under the most favorable orientations, lead to a. strain of only 6.9 pet; the contribution of twinning to the tensile strain would indeed be much less than this in a randomly oriented polycrystalline aggregate of magnesium. Since the three mechanisms of basal slip are coplanar, they are equivalent to only two independent mechanisms, a number insufficient for a general deformation. Consequently, once the permissible twinning has taken place in conjunction with basal slip, no further plastic deformation is possible because of interference to slip at the boundaries of dissimilarly oriented grains. At this stage brittle fracturing takes place due to high stress concentrations at the juncture of slip bands with the grain boundaries; the predominance of intergranular fracturing in magnesium, in preference to transcrystalline fracturing which is prevalent in zinc, has not yet been rationalized. A more atomistic description of the plastic behavior and fracture characteristics of magnesium follows from the analyses made by stroh4 on the stresses induced by piledup arrays of dislocations. Slip first takes place by dislocation motion in the most favorably oriented grains. As the dislocations approach the boundary of a dissimilarly oriented adjacent grain they begin to form an array of dislocations with its attendant stress field. Piledup arrays of screw and edge dislocations introduce high localized shear stresses at the spur of the array; piledup arrays of edge dislocations also induce high tensile stresses localized in the vicinity of the grain boundary. Whereas the shear stresses can induce slip to take place, the tensile stresses, if sufficiently high, can cause fracturing. The localized shear stress will be relieved if sufficient numbers of mechanisms of deformation become operative in the original and the adjacent grain to permit accommodation of the dislocations in the grain boundary. In this event a ductile behavior will be obtained. But if the number of deformation mechanisms is insufficient for complete migration of dislocation arrays into the grain boundary, the tensile stresses due to the edge components of piledup dislocation arrays will continue to increase with increasing applied stress until fracturing takes place. Whereas face-centered-cubic metals have a sufficient number of mechanisms of slip for accommodation of dislocations in their grain boundaries to exhibit ductile behavior, hexagonal-close-packed metals, in general, do not. Consequently, hexagonal-close-packed metals are usually brittle except when conditions such as alloying or temperature permit facile slip by a number of mechanisms. The arguments presented above suggest that the mechanical behavior of magnesium depends on whether or not dislocation arrays in adjacent grains can enter the grain boundary. When such accommodation is possible, ductile behavior is expected; but when such accommodation is impossible, fracturing will ensue. To further test the validity of these arguments it was considered advisable to study the

Jan 1, 1961

By Herbert Clark Hoover, Lou Henry Hoover

SINCE I have written of the varied work of pre- paring the ores, I will now write of the various methods of smelting them. Although those who bum, roast and calcinea the ore, take from it something which is mixed or combined with the metals ; and those who crush it with stamps take away much ; and those who wash, screen and sort it, take away still more; yet they cannot remove all which conceals the metal from the eye and renders it crude and unformed. Wherefore smelting is necessary, for by this means earths, solidified juices, and stones are separated from the metals so that they obtain their proper colour and become pure, and may be of great use to mankind in many ways. When the ore is smelted, those things which were mixed with the metal before it was melted are driven forth, because the metal is perfected by fire in this manner. Since metalliferous ores differ greatly amongst themselves, first as to the metals which they contain, then as to the quantity of the metal which is in them, and then by the fact that some are rapidly melted by fire and others slowly, there are, therefore, many methods of smelting. Constant practice has taught the

Jan 1, 1950

By Howard S. Bryant

Kansas maintained its fourth position on the list of all oil-producing states, for the ninth consecutive year. Total crude-oil production during 1935, as reported by the Oil & Gas Journal, was 53,364,446 bbl. on 97 per rent tank table calculations. This represented an increase of 17 per cent over the production in 1934, which had been the all-time peak of production in Kansas up to that time. Many of the 51 new discoveries of the year, listed in Table 2, did not have a pipe line outlet until about January, 1936; therefore did not contribute to the 1935 production of the state. The potential of all wells in Kansas at the end of the year was 998,-000 bbl. per day, and the daily allowable was 143,000 bbl. per day, showing proration to the extent of 14 per cent of capacity, under the rules of the State Corporation Commission. Several important new pipe lines were built into western Kansas by extending older lines from east to northwest, providing additional outlets for new crude-oil production, and increasing the service facilities from the older oil fields. The crude-oil price level remained unchanged throughout 1935 as it did in 1934, the price of Kansas 36" gravity crude being quoted at $1 per barrel. However, on Jan. 9, 1936, the price of this gravity oil was raised to $1.10 per barrel. Following the trend of the past several years, drilling activity was largely in western Kansas, and showed a still farther westward push from last year. A relatively high percentage of successful wildcat wells at a relatively shallow drilling depth, combined with the expiration of leased acreage assembled before the depression, caused the rapid exploration and development campaign, begun in 1934, to continue. This has caused the opening of more new fields in 1935 than during any previous year in the history of oil production in Kansas. A summary of the results of drilling in western Kansas is given in Table 2. Eastern Kansas had considerable drilling, showed six new fields or extensions of oil fields, but in the limited space of this paper such developments cannot be described.

Jan 1, 1936

By Geoffrey Gilbert

THE Montana Phosphate Products Co., subsidiary of the Consolidated Mining and Smelting Company of Canada, operates three phosphate properties north and northeast of Garrison, Powell County, Mont. Production of all three is from the same phosphate bed, a 3 to 4-ft. member of the Phosphoria formation, whose outcrop is traceable across the mountains of the Garnet Range in a series of southeasterly pitching folds. Because of topographical differences and of variations in the attitude of the bed, each property has its own mining methods and problems. Most of the phosphate rock produced since I930 has been shipped to the plant of the Consolidated Mining and Smelting Co. at Trail, B.C., where it is treated with sulphuric acid for conversion to phosphoric acid, which in turn is used to produce various fertilizers. HISTORY The occurrence of rock phosphate in Montana has been known. since 1910, and the Garrison area was mapped by the United States Geological Survey in 1913In the nineteen twenties William Anderson, owner of a ranch 8 miles north of Garrison, discovered phosphate on his land, and the Montana Phosphate Co., which later became the Montana Phosphate Products Co., was formed to work the deposit. Montana Phosphate Products Co. later obtained United States leases on two adjoining parcels of ground, and this combined property, known as the Anderson mine, has been the main source of Consolidated's phosphate rock. The mine now includes an adjoining parcel leased from Anaconda and mined from the Anderson workings. In 1940, the Graveley mine, a small privately owned property 6 miles east of the Anderson, was leased from the owner by Montana Phosphate Products Co., and a U. S. lease held by Graveley on some adjoining ground was subleased. In 1943 the Luke mine, on the Mineral Hill property, 1 ¾ miles south-southwest of the Graveley, a U. S. lease, which previously had produced a few thousand tons, was optioned from the lessees by Montana Phosphate Products Co., and is now being developed. At both these mines the rock is appreciably higher grade than at the Anderson mine. GEOLOGY The Phosphoria formation is the Permian member of an extensive sequence of Paleozoic and Mesozoic rocks. It is underlain by Pennsylvanian (Quadrant) quartzite and Mississippian limestone, and overlain without any marked unconformity by Jurassic (Ellis) shale and Cretaceous shale and sandstone. In the Garrison area, the Phosphoria itself consists mainly of about 50 ft. Of gray to yellow chert. Immediately below the chert is the phosphate, usually 3 to 4 ft. thick. Below the phosphate occur a few

Jan 1, 1945

By C. P. Sandberg

Having been occupied in inspecting and testing iron and steel these twenty years in England, and previous to that having served on the Board of Iron Masters in Sweden, I have naturally been very much interested in the subject of the use of steel for structures. I regret that I can offer but comparatively small experience on that had, having had principally to do with steel for railway plant and rails, but granting these to be a kind of "structure," and also that steel for rails has similar duties to perform in many respects, and is generally manufactured in the same way and at the same works as steel for stuctures, properly speaking, I may be entitled to offer an opinion on the use of steel in construction. In a paper recently presented to the Institution of Civil Engineers in London, Mr. Ewing Matheson has recommended that the Board of Trade rules should be amended so as to allow of a maximum straining of 8 tolls per square inch instead of 6 1/2 tons. But it is equally necessary to fix the amount of ductility or elongation of the metal for such a strain as 8 tons. Strength and ductility should always be spoken of together. Mr. Matheson says that steel can be manipulated in the factory in the same way and with the same tools as are used for iron. This can only be granted for mild steel; for hard steel would be spoilt by the rough mechanical treatment which iron can stand, such as punch ing, for instance; and the remedy for regaining the strength lost by punching hard steel, viz., annealing, cannot always be applied. Noth ing proves this fact better than the punching of steel rails of consid erable hardness, which caused fractures at an early period of steelunaking, and which resulted in the stipulation for drilling instead of punching the bolt-holes, which had been formerly applied to iron rails without any damage. In fact commissions to establish standard tests are now working on the Continent, principally in Germany, where

Jan 1, 1882

By Casimir Constable

DURING the years 1875 to 1879 I had charge of the Rockwood furnaces and mines, situated forty miles from the nearest railway communication at that time, and one hundred miles north of Chap tanooga, Tenn., by the Tennessee River. The small furnace with old-fashioned stoves, then in blast, was built under great difficulties by General Wilder. The early conditions were somewhat as follows: The ore was fossil ore of the Clinton group ; very fine and generally wet, without other admixture. The coke had a large amount of ash, and the fur" nace appeared to be badly scaffolded at times. On many days only a few tons of iron could be obtained. The founder generally id creased the revolutions of the engine when signs of chilling appeared,. The cinder at such times was black, very scoriatious, often closely resembling mill cinder. When the pressure was increased (the joints being the old-fashioned rust joints), leaks in the blast-pipe occurred It was noted that when the blast was stopped, and the leak bolt imperfectly remedied, the furnace improved a little. This set me thinking on the right track; and I took the responsibility of be coming my own founder for a time. A scaffolded condition had existed, and the situation was a trying one. Strange to say the negroes proved excellent furnace-men. Conceiving the hearth of the furnace to be similar to the grate area of a steam-boiler, capable of disposing of but so much fuel per hour, and requiring only a corresponding amount of air, it follows that an excess of air will burn the fuel not yet arrived at the hearth!, and raise the melting-point far above the tuyeres. This might pro duce scaffolding or at any rate choke the boshes, and leave less fuel to be consumed in the hearth. Thus for the time being less ail;. would be needed, as the continued burning of fuel in and above the boshes, would only aggravate the trouble. This condition of affairs accounted for the black cinder; the heat above having melted ore not yet perfectly reduced. This view decided me to reduce the revolutions of the engine; thefurnace finally became gray, as might have been expected. Any attempt to increase the speed produced black cinder and hard iron ;

Jan 1, 1883

By R. H. Thielemann

THE conventional short-time tensile test provides a reliable means of predicting the sustained load-carrying capacity of steels only when the temperature is such that continuous plastic flow does not occur. At elevated temperatures, stresses considerably less than the short-time rupture value may produce continuous flow, with fracture occurring only after long periods of time. The amount of flow or creep accompany-ing failure varies for different steels, and depends, to a large extent, on the temperature and the duration of the test. Service records of cracking stills, steam superheaters and high-temperature boilers have shown that brittle fractures sometimes occur with little or no warning. In installa-tions of this type, localized stresses are often encountered, and steels must be capable of withstanding a certain amount of deformation without fracture. The sustained-load rupture test determines the expected life and corresponding ductility of steels at various stresses and tempera-tures. It also yields additional information regarding the effect of micro-structure and metallurgical stability on the high-temperature properties.

Jan 1, 1939

By B. F. Koch

COPPER reverberatories develop large amounts of exit gases of a temperature in the neighborhood of 2000°F. The gases are not only of a noxious nature but must usually be disposed of at considerable heights above the yard level by a stack. Handling these gases at the temperature mentioned would require rather expensive construction of conveying flues and stack. Moreover, wasting such amounts of heat is certainly most uneconomical. Numerous investigations have indicated that waste heat boilers of the water-tube type are the most practical and economical means for utilizing that heat although the gases are heavily laden with rock dust and copper-bearing slag, which upon cooling form hard deposits on the surfaces of dampers or heat absorbing elements placed in the gas stream. Avoiding Slag and Dust Deposits Based largely on the experience of the paper industry in burning black liquor, a waste heat boiler design was developed a few years ago, providing not only extensive water-wall surfaces for cooling the gases below the fusing point of the slag but also settling out, as far as possible, the solidified particles of slag by creating low gas velocity. Matter carried in a stream of gases or air has a tendency to maintain its original direction upon a change in the direction of the flow of the conveying medium. Reverberatory waste heat boilers installed at Hurley and Morenci endeavored to utilize that tendency for the elimination of slagging particles at predetermined places and before they would strike the tube banks of the boilers. Both installations were successful in minimizing the slagging of boiler tubes and thereby minimizing the need for hand lancing. However, the low draft carried at the up-take of the reverberatory furnaces resulted in a positive pressure in the upper part of the furnace of the waste heat boilers, causing the emission of gases from lancing doors and making more difficult the already unwelcome work of cleaning the boilers by handlancing. Attempting to correct this nuisance as much as possible, the overall height of the Chuquicamata waste heat boilers has been reduced to the minimum considered necessary to obtain proper water circulation in furnace walls. Moreover, it is attempted to solidify slag and dust particles by providing large amounts of water-cooled surfaces before the gas stream reaches super-heater and convection banks of the boilers. The furnaces have been made as deep as an economical and practical arrangement of headers for water

Jan 1, 1952

By T. M. Chance

THE first bituminous coal cleaning-plant to use the sand-flotation process1 was placed in operation on Oct. 1, 1925, at the tipple of the East Broad Top Railroad & Coal Co., at Mt. Union, Pa. The general principles governing the design of plants of this type and typical operating results of anthracite sand-flotation units have been previously outlined.2 I will, therefore, confine myself to a description of this particular plant and to some of the elements of design it incorporates. THE ORIGINAL MT. UNION TIPPLE The plant was installed to transfer coal from steel narrow-gage cars of 60,000 and 70,000 lbs. capacity to standard-gage equipment. The coal was hauled some 30 miles from the East Broad Top field. This coal, mined by the Rockhill Coal & Iron Co. and other operators, is a low-volatile slow-coking coal with- ash of high-fusion point. It is normally a high-grade coal that does not contain an excessive amount of free impurities, but it requires careful handling to secure a fair domestic yield, and, naturally, the need for narrow-gage transshipment increases the difficulty of the problem. The narrow-gage cars were discharged into an 8-car track hopper equipped with two feeders passing the coal to two 42-in. apron intake conveyors. Twin units were installed throughout in this original plant, two lump-and-egg shaking screens, two lump picking-tables, two egg picking-tables and two stoker conveyors. The stoker coal was loaded without cleaning. The loading tracks and booms were in duplicate and with the layout as originally installed either unit could be run independently, each unit shipping a different class of coal or both units making the same product.

Jan 2, 1926

Falconbridge Nickel, the one-time subsidiary that grew up to swallow its own parent, Ventures Limited, in 1962, is not about to be left behind by rising nickel consumption. At a cost of several hundred million dollars, this Canadian firm has undertaken a series of new projects that will not only ensure its present share of the market, but also lead it into new areas of the nickel business. Although Falconbridge Nickel Mines Ltd. was not formed until 1928, it actually had its start in 1917- 18 with the discovery of a large, good grade nickel- copper deposit in Falconbridge, near Sudbury, Ontario. However, due to several factors, financing could not be obtained and the orebody lay fallow. It was not until 1928, when the Thayer Lindsley interests bought the property from the original owner, that it was developed.

Jan 10, 1968

By E. C. Lee

The safety of mine workers has received more attention from both State and Federal law-making bodies than any other industry, a fact that shows clearly the hazardous nature of the industry. The last, but by no means the least, of the measures adopted for the protection of mine workers, is workmen's compensation legislation. This is proving to be a powerful instrument for greater safety in the industries, from the fact that special stress is laid not on how the accident happened or who may have been responsible for it, but on how badly the employee is hurt by it. The injured person does not have to employ lawyers to prove his case, because- the mere fact of his employment is proof of his right to compensation. The immediate effect of such legislation is the certainty confronting the mine operator that he must. pay out large sums for every accident, regardless of its cause, thus adding materially to the cost of the production of his coal. his fact furnished to the operator the strongest incentive to reduce the causes of accidents; not that the operator has ever lacked reasonable consideration for the welfare of his employees and a proper humane interest in their safety, but his engrossmentin earning his daily livelihood has been so great that he has not felt that he had the time to devote to the safety of the operation. This time he must now find because of the actual cash value of the prevention of accidents in his mines. This agency alone proved inadequate to bring about a material improvement because operators have always been willing enough to improve safety conditions when possible to do so within reasonable limits of their financial ability. The requirement in the Workmen's Compensation Laws of several of the States, that the mine operator shall insure as a guarantee of his ability to meet his compensation obligations, has furnished the needed incentive, moral and financial, necessary to the prompt and effective dissemination of a more general knowledge of the causes and

Jan 1, 1918

By Rossiter W. Raymond

BY the courtesy of Mr. Charles W. Jenks, of Boston, one of the owners of this interesting mine, I am enabled to lay before the Institute a suite of specimens, illustrating its peculiar formation and the paragenesis of mineral species which it presents; and a recent brief visit and rapid reconnoissance of the locality permit me to supplement this exhibition with a general description, based upon personal observation. The mine is situated upon the Culsagee Fork of the Tennessee River, in Macon County, North Carolina, a few miles from Franklin. The most practicable route by which it can at present be visited is by wagon (or preferably on horseback) from Seneca City, S. C., a station on the Charlotte and Atlanta Air Line Railroad. The itinerary is as follows: to Walhalla,* nine miles; Walhalla to Highlands, twenty-nine miles; Highlands to the Culsagee, fourteen miles. By passing the night at or near Highlands, the mine can be reached and examined and the return to Highlands made on the second day; and the round trip, if performed in the saddle, can be completed in three days from Seneca City. It is not easy, with due regard to steed and rider, to do it in less time. The rough and precipitous mountain roads do not permit rapid travel ; and the journey is at best a fatiguing one. But its slight hardships are overpaid by the stimulating effect of the climate and the great beauty of the scenery, both of which are destined to become more widely known than at present, to seekers for health and pleasure. Indeed the town of Highlands, already named, is almost entirely made up of northern immigrants, attracted by these advantages and by the inducement of cheap land for agriculture and stock-raising. The Culsagee or Sugartown fork of the Tennessee traverses the belt of ancient crystalline schists on the west flank of the Blue Ridge. This belt abounds in valuable minerals. Among those of the nonmetallic class may be mentioned graphite, soapstone, serpentine, ashes- * A branch or cross railroad is in operation as far as Walhalla ; but the single daily train runs at an hour not convenient for this expedition ; and Seneca City is probably the best starting-point. At all events, I obtained there an excellent mount for the trip.

Jan 1, 1879

By S. L. Payne, J. P. Morris, R. L. Kipp, G. R. Zellars

The activities of iron and nickel in liquid Fe-Ni alloys were determined by measuring the vapor pressures of iron and nickel above the alloys and comparing with the vapor pressures of the pure metals. Nickel was found to deviate negatively from Raoult's law over the entire composition range. Iron behaves ideally down to 0.7 mole fraction but shows negative deviations at lower concentrations. At 1600°C the activity coefficients at infinite dilution are 0.40 for iron and 0.66 for nickel. 1 HE formulation of the conditions of chemical equilibrium between liquid metals and gases or slags is an important application of thermodynamics to pro- cess metallurgy. Usually the metal and slag phases are solutions of several components; and for accurate calculations, it is often necessary to use the activities of the components in place of their concentrations. Data concerning activities, however, are quite meager. The evaluation of the activities of iron and nickel, presented in this paper, is part of a project to determine activities in iron alloys at elevated temperatures.

Jan 1, 1960

Discussion of the paper of E. C. HARDER, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October, 1914, pp. 2573 to 2586. I. C. WHITE, Morgantown, W. Va.-I have seen some of the great iron-ore deposits described in this paper. -One of these in the State of Minas Geraes appears to be an immense mountain of iron ore about 2,000 ft. in height. All over its surface from bottom to top may be seen large masses of rich iron ore, varying in weight from a few pounds to several tons, and from all that one can judge without exploitation, the quantity of available ore is certainly very large in this particular mountain. Whether it will prove a mere surface deposit or shell, like the famous Iron Mountain of Missouri, is for future exploration to determine. The question of transportation is the main factor in determining the availability for exportation of these Brazilian iron ores. There is no coal in Brazil that can be manufactured into coke without expensive previous treatment, since the best of the raw coal in the States of Rio Grande do Sul, Santa Catharina, and Parana, contains about 35 per cent. of ash, of which about 6 per cent. is sulphur, and coal of this composition cannot be utilized in iron smelting without purification. When I was chief of the Brazilian Coal Commission in 1904 to 1906, I had a cargo of this coal shipped to Balk, Germany, and treated in the great coal-testing plant of the Humboldt Engineering Works, located just across the Rhine from Cologne. It was found that by crushing and washing the Brazilian coal, it yielded 33 per cent. of briquetting coal, containing only 10 to 12 per cent. of ash (of which 1 per cent. was sulphur), and 42 per cent. of slack coal, with 25 per cent. of ash and low in sulphur, so that about 33 per cent. of the Brazilian coal could be converted into coke of fair quality, as shown by the following average of three analyses, using air-dried coal, of briquets made from the Barro Branco coal bed, State of Santa Catharina: Moisture 1.56 Volatile matter 31.66 Fixed carbon 56.73 Ash : 10.05 Total 100.00 Sulphur 1.34 Phosphorus 0.003 B.t.u 13,395

Jan 4, 1915

Application of Kutter's Formula to Gases Discussion of paper by F.-ERNEST BRACKETT, presented at the Pittsburgh Meeting and issued, as Pamphlet No. 1578-A-F, with MINING AND METALLURGY, June. 1926. C. S. WITHERELL, New York, N. Y..(written discussion).-There is no reason to doubt that the relationship between the rate of, flow and. the impelling force of all fluids can be expressed by a general typical equation that takes cognizance of all relevant factors such as density, viscosity (or its reciprocal, mobility) and nature of channel-walls. Most fluids that are commonly conveyed by flow in confined channels are so highly mobile that they may be considered non-viscous, hence for these fluids the factor of viscosity does not need to appear in the equation. Water is the outstanding example of this class of fluids and its dynamic behavior has been so thoroughly investigated that proven formulas pertaining thereto, be they rational or empirical, would naturally serve as prototypes for the other non-viscous fluids. As non-viscous fluids can be classed all gases and vapors, most unsaturated aqueous solutions, gasoline, alcohol, etc. Viscous fluids comprise those that have a sluggish flow such as most oils, tar, molasses, etc., the' high viscosity of which is due to shearing resistance between molecules, a force that must betaken into account in figuring the flow of fluids of this class.

Jan 10, 1926

By A. Q. Tool

THE necessity of accurate temperature measurements in the glass-making industries is today being much more widely appreciated than in the past. The introduction of the modern simplified and perfected pyrometric methods in connection with exact regulation of furnace temperatures has caused a marked improvement in the glass product with a quickened rate of production. An example of the processes in which much improvement has been and still can be made is that of annealing or heat-treating the glass. This is one of the most delicate processes in glass manufacture and one that requires a most careful furnace control. The heat treatment is undertaken to decrease the possibility of breakage and, in glass for fine optical instruments, to prevent serious warping of accurately ground and polished surfaces and to make the glass more uniform throughout to the passage of light waves. These objects are accomplished by removing all the harmful stresses that exist in a piece of glass when it has been cooled too quickly or unevenly. Such stresses exist, for example, after it has been pressed, cast, or otherwise worked. Thus the process of annealing consists of heating the glass evenly to the temperature at which it softens just enough to relieve these stresses in a reasonable time and then cooling slowly and uniformly until the glass hardens again. Accordingly, the things that must be investigated and determined in order to anneal glass without loss of time are, the annealing temperature, the time that the glass should be held at this temperature while the stresses relax, and the quickest cooling procedure that will give satisfactory results. After these characteristics of the glass are known the problem is one of pyrometry and temperature control entirely. In cases when it is known that a glass article will be required to withstand some definite type of heat or mechanical shock it is often possible, by a proper heat treatment, to produce such a distribution of the stresses in the glass that it will be enabled to resist these shocks more effectively.

Jan 9, 1919

By J. H. Wiggins

Granting that about 600,000,000 bbl. of light oil will be produced in the United States this year and taking the Bureau of Mines' statement that 71/2 per cent. of the total crude production will be lost before the finished gasoline is shipped from the refinery, the volumetric evaporation will be 45,000,000 bbl. of the cream of the gasoline. This is a ConseNative figure and is equivalent to 1,890,000,000 gal. The real value of this liquid is at least 150 per cent. of the value of an equal volume of motor fuel. At only 10 c. per gal., the value lost is $189,000,000; at 15 e. per gal. the loss is $283,000,000. If 750,000,000 bbl. of light and heavy oil are produced here this year and the average price per barrel is $1.333, the gross return to producers will be $1,000,000,000 and the net returns about $200,000,000, if the cost of production is only $1 per barrel. Thus, the evaporation bill is about 20 per cent. of the gross income and is equal to the net income of the crude-oil producers. Two other comparisons with popular phases of the petroleum industry will help give an adequate conception of the evaporation problem. These are: cost of preventing evaporation compared to cost of cracked gasoline and volume of gasoline evaporated compared to volume of gasoline manufactured from natural gas. When gasoline is manufactured from heavy oils by the cracking process, there are two important divisions of the total cost of the product: the manufacturing cost, such as plant cost, operation, maintenance, etc., and the cost of the barrel of heavy oil, from which the cracked gasoline is made. In preventing evaporation loss the cost first mentioned enters into the total cost, but the second cost is eliminated; that is, no charge is necessary for stock from which to manufacture the saving. A detailed analysis of these two costs on a large scale shows that the net income from a dollar spent in preventing evaporation loss from the lease through the refinery is twice the net income from a dollar spent in cracking. Of

Jan 1, 1924

By Howard S. Bryant

Kansas maintained its fourth position on the list of all oil-producing states, for the ninth consecutive year. Total crude-oil production during 1935, as reported by the Oil & Gas Journal, was 53,364,446 bbl. on 97 per rent tank table calculations. This represented an increase of 17 per cent over the production in 1934, which had been the all-time peak of production in Kansas up to that time. Many of the 51 new discoveries of the year, listed in Table 2, did not have a pipe line outlet until about January, 1936; therefore did not contribute to the 1935 production of the state. The potential of all wells in Kansas at the end of the year was 998,-000 bbl. per day, and the daily allowable was 143,000 bbl. per day, showing proration to the extent of 14 per cent of capacity, under the rules of the State Corporation Commission. Several important new pipe lines were built into western Kansas by extending older lines from east to northwest, providing additional outlets for new crude-oil production, and increasing the service facilities from the older oil fields. The crude-oil price level remained unchanged throughout 1935 as it did in 1934, the price of Kansas 36" gravity crude being quoted at $1 per barrel. However, on Jan. 9, 1936, the price of this gravity oil was raised to $1.10 per barrel. Following the trend of the past several years, drilling activity was largely in western Kansas, and showed a still farther westward push from last year. A relatively high percentage of successful wildcat wells at a relatively shallow drilling depth, combined with the expiration of leased acreage assembled before the depression, caused the rapid exploration and development campaign, begun in 1934, to continue. This has caused the opening of more new fields in 1935 than during any previous year in the history of oil production in Kansas. A summary of the results of drilling in western Kansas is given in Table 2. Eastern Kansas had considerable drilling, showed six new fields or extensions of oil fields, but in the limited space of this paper such developments cannot be described.

Jan 1, 1936

By H. B. C. Nitze

A description of some of the magnetic ore-deposits in this region should be of interest to the mining and metallurgical public, inasmuch as very little has been said or written concerning them. I refer to the magnetite deposits of Franklin and Henry counties, Va., and of Stokes county, N. C. These deposits remained comparatively unexplored until recently, when the construction of the Roanoke & Southern R. R. through this territory has called attention to them, by furnishing the means of transportation for the ores. It is true that the ores have long been known, at least locally, and were smelted in catalan forges and old-fashioned, cold-blast charcoal-furnaces long before and during the late war. At the present time, however, the old workings are caved in, filled up and over-grown to such an extent that, as a rule, but little can be learned from them. No prospecting of any consequence has been done, and as my time was too limited and the territory to be examined too extensive to permit additional openings of a more satisfactory nature to be made, the incormpleteness of some of the data I have to offer (notably, those referring to the absolute width of the veins) will be pardoned. It will hardly be necessary to say that this ore-bearing formation belongs to the Archaean, or Eozoic age, the usually occurring rocks being schist, shale, gneiss, granite, sandstone and quartzite. The stratigraphy is, as a rule, quite regular (excepting in the Danbury section, Stokes county, N. C.), the general strike being northeast and southwest, and the dip nearly vertical. The country is gently roll-

Jan 1, 1892

By Arthur Phillips, C. H. Mathewson

During the past year considerable work dealing with the mechanical properties and microstructure following the anneal under uniform condi-tions of certain types of commercial rolled brass has been done in this laboratory. Since these experiments were conducted with the active cooperation of the Bridgeport Brass Co., involving free use of its product, and have thus furnished information which is characteristic of some of its special mixtures, full publication of the numerical relationships and comparative results encountered does not seem justifiable. Some of the more general features of this work are, however, available and it is our present purpose to use the material in question, along with some results of special tests, in discussing the characteristics of recrystallization as related to the degree of hardening by strain and the ordinary annealing variables. We desire to make acknowledgment of the many courtesies extended by Mr. Charles Ferry, Metallurgist of the Bridgeport Brass Co., and the value of his cooperation, which has greatly stimulated the study of brass in this laboratory. A clear and systematic presentation of the principal relations between temperature and time of anneal, the changing physical properties and microstructure and the degree of previous reduction by cold-rolling, was first made, in the case of rolled brass and copper, by the French engineer, C. Grard,' in 1909, although much fragmentary information of this general character had appeared earlier and the main facts involved were undoubtedly known to many brass specialists through their own private research. From this work, it appears that in the cartridge mixture (67 per cent. copper, 33 per cent. zinc) the properties imparted by cold-working within the limits, 13 to 75 per cent, reduction of area by rolling Original Area — Final Area 0.13 to 0.75), are not affected by anneal- Original Area " ing for a 50-min. period at any temperature below 200°C. At or in the

Jan 1, 1916