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By G. P. Walters, W. C. Fuller

THE production of thin films of beryllium became essential early in the irradiation program at Harwell in order to study the fundamentals of irradiation damage in this metal. In common with other metals, electron-microacope specimens of beryllium can be produced by different techniques. The techniques used to produce thin-film specimens varied according to the starting material. Most of the starting material was -0.060 in. thick. Large-area specimens (1 in. long by 0.5 in. wide) were chemically thinned to -0.005 in. thick in a solution containing 85 pct orthophosphoric acid, 10 pct chromium trioxide, and 5 pct sulfuric acid at 70°C prior to electropolishing. Small-area specimens, Fig. 1, had to be mechanically thinned prior to electropolishing because chemical thinning considerably reduces the area as well as the thickness. Mechanical thinning tends to produce a worked layer about 0.002 in. deep and hence this method cannot be used to thin bulk specimens below about 0.005 in. thick. Mechanical thinning is carried out by mounting the specimen on perspex then carefully polishing on wet grinding papers. Polishing is continued until about half the initial thickness is removed; the reverse side is then polished in a similar manner. After the bulk specimens have been mechanically or chemically thinned to -0.005 in. they are elec-tropolished in the solution shown in able I at 50" to 80°C. This solution should be prepared by adding the chromium trioxide to the orthophosphoric acid and then the glycerol last. The glycerol should be added slowly because a vigorous effervescence can occur. Electropolishing is carried out by holding the specimen in stainless-steel tweezers and gently agitating in the solution. Masking or "window" techniques are not required for beryllium, good microscope specimens being obtained from the edges of elec-tropolished foils. A stainless-steel beaker should be used, acting as the cathode and solution container. A closed circuit voltage of 30 v is used for polishing. Too low a voltage produces a matt surface and pitting occurs when it is too high. The solution temperature is important. If it is too low, the solution is viscous and bad polishing results and, if too high, etching of the specimen occurs. After electropolishing, the foils are thoroughly

Jan 1, 1963

By J. R. Campbell

In order to discuss the subject intelligently, it will be necessary to touch briefly on the forms in which sulphur is supposed to exist in coking coal to be carbonized in beehive or byproduct ovens. Sulphur is known to exist in coal as sulphides and sulphates, as can be determined experimentally. Then there is the so-called organic sulphur, i.e., sulphur in combination with the carbon, 'hydrogen, and oxygen of the coal, about which much has been written, but nothing definitely proven in an experimental way. In fact, so far. as we know, there never has been developed a satisfactory and conclusive method in the laboratory for the direct determination of organic sulphur. For most coking coals, it can be safely assumed that the preponderance of sulphur is in the form of pyrite (FeSz). When exposed to comparatively low temperatures during the coking process, it loses its sulphur according to the following chemical reaction: 7FeS2 = Fe7Ss + 6S. It will be seen, therefore, that six out of the 14 atoms of sulphur (or 42.8 per cent.) are expelled, or volatilized. FelSa remains in the coke as pyrrhotite, or magnetic sulphide of iron; this accounts for the highly magnetic properties of the powdered coke. A more commonly accepted reaction is FeS2 = FeS f S, in which the straight sulphide of iron is produced with 50 per cent. volatilization of sulphur. In the beehive methods of coke making, air is introduced in sufficient amounts to carry on the distilling and the coking processes, and the sulphur is oxidized along with the other volatile products: First, into sulphur dioxide (SO2), known by the pungent andsuffocating odoremitted from the trunnel head; second, into sulphuric anhydride (SOa); and, finally, into sulphuric acid, as it comes into contact with the air and moisture. In a properly regulated draft on a beehive oven, there is never complete combustion of the gases. In other words, the coking process should be carried on in a reducing atmosphere, and a low-grade producer gas kept issuing from the trunnel head. For coals of about 30 per cent. volatile matter, the ratio of air to gas is 3½ to 1. In complete combustion, the ratio is 6 to 1, producing an extremely high temperature

Jan 1, 1916

By E. G. Dean

A method of top slicing has been devised at the Miami Copper Co.'s mine at Miami, Aria., which differs radically in some ways from the customary methods of top slicing. The area of that section of the orebody in which top slicing is used is about 800 ft. square. The ore, while for the most part soft, is, nevertheless, considerably harder than the capping. The latter is siliceous, seldom containing any clay or other binding material, and breaks into fine particles so that it runs like sand if given the opportunity. Because of these facts, and because the ore is above the average grade of the mine ore, it has been mined by top slicing. Haulage levels are opened up 150 ft. apart, vertically, with two sub-levels between at 50-ft. intervals, to facilitate the putting up of ore chutes. These sublevels are used during slicing for distributing air in the ventilation system. On the haulage level the drifts are spaced on 50-ft. centers, and raises along these drifts are also spaced on 50-ft. centers, except the incline raises as hereafter noted. The raises are cribbed where necessary. Where the wear will be excessive, 1/4-in. iron plates are spiked to the top of every third set of cribbing, for its protection. When top slicing was first used, an attempt was made to carry a slicing face from fifty to several hundred feet long. Timber and other supplies were brought in through long drifts from an auxiliary shaft. Great difficulty was experienced in keeping these drifts open, the side pressure breaking the posts and the top weight breaking both caps and posts. Furthermore, the men could not work efficiently while these drifts were being repaired. The slicing faces advanced irregularly, due to varying conditions, and in many ways the results were not all that could be desired. It was then decided to divide the slicing area into blocks 200 ft. square and this was later changed to 250 ft. square. At the center of each block a two-compartment raise is put up as a supply raise, the compartments being 2 ft. 6 in. and 4 ft. by 4 ft. 4 in., the smaller being used as a manway. Station sets of 12 by 12 timber with

Jan 1, 1917

By Lester Guttman

THE connection between short-range order and thermodynamic activities in binary solid solutions has been pointed out by Birchenall1 who calculated approximate values of the energy of interaction of Zn and Cu and of the degree of short-range order in alpha-brass at one composition and two temperatures. The purpose of this note is to call attention to a somewhat more accurate theory than that used by Birchenall and to extend the calculations to a wider range of temperatures and compositions as a means of testing its applicability. This is an example of the well-known general method of comparing measured thermo-dynamic functions of a system with those calculated from a microscopic model by means of statistical mechanics. In this case, mathematical approximations must be used which make difficult any decision about the validity of the model. Birchenall's statistical method resembles closely that called by Fowler and Guggenheim2 the "quasi-chemical" method which has been shown to lead in certain cases to results identical with those obtained by the method of Bethe.3 The quasi-chemical method has been extended by Takagi4 to give general formulae for the free energy of binary solid solutions based on several lattices at all compositions and temperatures. Specifically, he treats the four systems typified by: I. ß-brass; 2. a- brass; 3. AuCu3; 4. AuCu. When the temperature is so high that no long-range order exists, these formulae reduce to the same form for all lattice types, namely: [ ] Here the symbols have the following meanings: [F-Helmholtz free energy E-energy S-entropy k-the gas constant per molecule z-coordination number, (e.g. 12 in. a-brass). N-total number of atoms c-atomic fraction of A] VAA, VBB, VAB-energy per bond of the corresponding bonds log means log, throughout The superscript 0 denotes the thermo- dynamic function in the standard state, which has been chosen to be pure A or B with the same crystal structure as the solid solution. The quantity x is the ratio of the number of A-A bonds to the total number and for minimum F satisfies the equilibrium condition [ ] The free energy may also be written in terms of µA and µB, the chemical potentials or partial free energies per atom:

Jan 1, 1948

By Edward D. Peters

IT frequently occurs in the establishment of reduction works, in an entirely new and untried mining district, that the metallurgist in charge finds considerable difficulty in determining the process best adapted to the ores which he receives for treatment. At the first glance it would seem easy enough to decide what style of furnace is best adapted for beneficiating any one class of minerals. If the ore possessed a quartzose gangue and was comparatively free from base metals, while salt could be obtained at a reasonable price, one would naturally resort to a chloridizing roasting, and pan or barrel amalgamation for the extraction of its silver contents. If galena or carbonate of lead was the prevailing mineral, and charcoal could be obtained at moderate figures, the blast-furnace would beneficiate the ores most advantageously. But if, as is usually the case in Colorado, the ores consisted of an intimate mixture of galena, zinc-blende, copper-pyrites, and noble silver minerals, associated with an overwhelming mass of siliceous heavy spar, or limestone gangue, the common reverberatory furnace can be used to the greatest advantage; and, although the product is only a copper matte, I do not hesitate to affirm that it can be treated, and the silver, gold, and copper produced at nearly the same price for which silver and lead can be separated. In Germany, blast-furnaces are frequently used for this same purpose, both for argentiferous and non-argentiferous copper ores ; but any one who will take the trouble to examine the statistics of smelting at Fahlun, the Oberharz, and other Continental works of this description, will see that the expenses are far too great, and the production much too small to think of employing this method in our mining districts, where only the softest and most miserable kind of charcoal is obtainable. I propose in this paper to give an accurate account of the expenses incurred at the Mount Lincoln Smelting Works in treating the same kind of ore, and producing the same end-product in both blast and reverberatory furnaces. I have taken for comparison a favorable campaign of the blast-furnace, and a good average month's running of the reverberatory. In the blast-furnace estimate I have included the calcining and concentration of the matte produced during that campaign, as I always, when possible, concentrated the regulus made

Jan 1, 1874

By P. P. Gregory

Natural petroleum gas occurring in the oil-bearing reservoirs is found to exist either as free gas associated with the oil and/or in solution in the oil. In some virgin fields practically no free gas is encountered under the reservoir conditions of pressure and temperature, although in other fields a considerable section of the "pay" horizon is occupied by free gas. In other words, a given oil field may or may not have a gas cap before the exploitation takes place. However, when the reservoir pressure is reduced to a point below the critical saturation pressure by withdrawals of fluids from the producing formation, the gas dissolved in the oil inevitably begins to come out of solution and becomes free gas. Under the controlled methods of production and drilling, a portion of this gas is produced with the oil to the surface and a portion of it remains within the reservoir to accumulate at higher structural levels toward which it migrates by virtue of its low specific gravity. The rate of growth of a gas cap in a given structure depends primarily upon the rate of decline in the reservoir pressure. If the rate of pressure decline is rapid, the gas cap likewise will grow rapidly. On the other hand, shrinkage in the gas-cap area was noted in some fields in which reservoir pressures wereincreasing. Determination of Gas-oil Contact and Thickness of Gas Cap The gas-oil contact can be conveniently located in the process of drilling a well and by electrical logging. However, very little can be found in the petroleum literature concerning methods of predetermining gas-oil contacts in producing reservoirs. Therefore, the writer feels justified in describing briefly a simple, workable, and inexpensive method of determining gas-oil contacts and outlining the limits of gas-cap areas in a field where such knowledge may be essential for efficient production and development operations. The method involves the determination of the following data: (I) Structural data, such as the depth or elevation of the top' of "pay" horizon; (2) reservoir pressures; (3) tubing and casing pressures at the well head; (4) static oil-pressure gradient; (5) static gas-pressure gradient. These data can be secured with a minimum of expense, inasmuch as the

Jan 1, 1938

He took a great interest in technical matters and his inclination was strongly toward research investigations. At the same time he was effective in manual and mechanical work and was generally found working side by side with the men under his direction. His nature was unselfish and he was extremely popular socially. He was a member of the Coeur d'Alene Commandery, Knights Templar. Stanly A. Easton. Lieutenant.Louis Baird Louis Baird, a Lieutenant in the Royal Field Artillery of the British Army, died on the battlefield in 1915. Lieutenant Baird was born July 28, 1880, at Stirling, Scotland. His technical education was obtained at King's College, Melbourne, Australia, in 1893 to 1895, and at the Technical College at Glasgow, Scotland, in 1897 to 1900. After an apprenticeship with the Mexican J. & 8. Rec. Co. of Mexico, lasting from 1900 to 1903, he became mill superintendent for the Cia. Minera Benito, at Juarez, Zac. During the year 1905-6 he was assistant manager of the Caridelaria y Anexas, at Pinos, Zac., and from 1906 to 1907 was engineer with the Cia. Minera Jalisco, San Sebastian, Jalisco. At the time of his admission to the Institute, in 1908, he was practising as a mining engineer at Etzatlan, Jalisco, Mexico. For the next four years he practised his profession in the City of Guadalajara, Jalisco, removing, in 1913, to Ixtlan del Rio, in the State of Tepic. It was from here that he returned to England to put his services at the disposal of the British Government. The Institute is not definitely informed as to how, where, or when Lieutenant Baird met his death. iCaptain John H. Ballamy John H. Ballamy, Captain on the Regimental Staff of the 103d Engineers, was killed near Fismes, on Aug. 9, 1918. Captain Ballamy was born at Plvmouth. Pa.. in 1886 and graduated from' the High School of that town in 1903. In the following year he began work as a coal miner, and at the same time began the study of mining engineering in the evening and any other spare time. He continued this diligent and energetic practice for many years. For sixteen years he continued in the employment of the Delaware, Lackawanna & Western Rai1roa.d Company's coal mining

Jan 1, 1920

By W. R. Clough, M. E. Shank

IT has been noted in a study of the flow and fracture of nodular cast iron under biaxial stress conditions (complete results of which will be published later) that when this metal is subjected to stress it may undergo a striking density change. Such behavior was first determined by strain gage measurements made on tensile test specimens, and has since been substantiated by other types of measurement. The chemical analyses and mechanical properties of several nodular irons to be discussed here are given in Tables I and 11. Tensile data for iron A was obtained from a hollow cylindrical combined stress specimen of the same dimension as those used by L. F. Coffin, Jr.1 in his investigation of gray iron properties. Standard 0.505 in. solid tensile-test bars were used for irons B and C. On each specimen type, A-8 wire resistance strain gages were used—two diametrically opposing gages in the axial direction, two in the tangential or hoop direction. By subtracting elastic strains from the measured strains, the plastic strains could be calculated. By assuming that radial and tangential strains are numerically equal, a measure of permanent volume change can be obtained by summing the plastic strains. This appears to be a good assumption, since the metal either fractured, iron A, or readings were discontinued, irons B and C, long before necking took place. This calculated variation of volume increase with stress is given for irons A and B in Fig. 1. Data for iron C is almost identical with that for iron B. The volume change indicated by Fig. 1 has been substantiated by a more direct type of density measurement. A method developed by S. G. Fletcher and' Morris Cohen,' and completely described in the discussion of their article, has been used. The accuracy of specific volume measurement has been estimated as 0.00002 cu cm per gram. Essentially the method consists of weighing a sample in air and then immersed in water. Measurements were made before and after straining the material. The results shown in Table I11 were obtained by means of half-size (0.252 in. diameter, 1 in. gage length, 3/8-16 threads) tensile specimens. Initial measurements were made on the whole specimen before stressing. After stress-

Jan 1, 1955

By George Riter

OUR mineral-land laws need revising so as to provide definite title at the outset to the mineral deposits within any definite piece of land. The laws as they now stand, especially those applicable to lodes, breed uncertainty as to rights of possession prior to patent; and to my mind this is the worst feature of all, worse even than the apex bugbear. It is now almost impossible for anybody to tell with certainty what mineral rights exist within any area that is not covered y patent, or whether any valid rights exist at all. Our system is unique in permitting individuals to appropriate and exploit mineral lands of the public domain without notice of any kind to the Federal government, and to relinquish them without any ceremony at all. The result is a clouded record that cannot be cleared' up until each claimant is put to some sort of final proof. In order to accomplish this, new Federal legislation will be required. The requirements for a mineral survey and the proceedings for patent have always been cumbersome and expensive; and perhaps out of regard for the poor claim owner, who can ill afford the outlay for that sort of thing, the law does not require him to go through it unless he chooses to do so. Consequently, every active mining district has become encumbered with tangled groups of doubtful or conflicting locations, whose rights and boundaries, when any valuable ore is found, must usually be determined by lawsuits that are as expensive and as distressing as the stakes are high. So deeply has litigation entered into our mining system that a claim whose rights have never been disputed would probably be set down offhand, y a miner of the old school, as of no value. Think of the litigation over rights of possession on the Comstock lode-12 leading companies involved in an aggregate of 245 suits within a period of less than eight years! Ambiguous local records; the chance of erroneously placed or obliterated monuments; doubt as to the sufficient performance of the statutory annual labor; uncertainty as to prior conflicting or overlapping locations; anxiety as to the changing attitude of the Department of the Interior and the Forest Service-such considerations as these make an unpatented mining claim an unclean thing in the eyes of possible investors. Is it any wonder that they keep themselves and their money at a safe distance,

Jan 7, 1914

By Carl Zapffe

Because no rock outcrops exist in the Cuyuna district, it is necessary first to make a magnetic survey with a dip needle, or possibly with a sun-dial compass, and determine the area or belt of magnetic variations and the maximum lines of magnetic attraction. A dip-needle survey is quicker to make, is sufficiently accurate, and will suffice. Regardless of how poorly defined the magnetic attractions may be, it is important that they be determined. Even if drilling has developed ore on an adjoining property, the survey should not be omitted. Iron-bearing formation is indicated by the magnetic attractions, but whether or not ore exists must be determined by drilling. The maximum line of magnetic attraction offers the best place to begin drilling. If no magnetic attraction exists, nearby developments are the only guide; and if these also are lacking, drilling is governed by guess. Test-pitting is not employed in exploratory work because the surface is too deep. Tunneling cannot be used because the topography is not suitable. Exploration shafts are a waste of time and expense, because from every standpoint drilling with churn and diamond drills is the most applicable method for exploratory work. Light drilling equipment only is needed. Rarely have heavier drills been required, for seldom do holes exceed 400 ft. in depth, and about 100 ft. of this is in glacial drift which is easy to penetrate. The deepest hole is 1023 ft. Because of the steep inclination of the strata and the narrowness of the orebodies, many angle holes have been drilled, mostly at 60' to 70" from the horizontal and against the dip of the formation. Angle holes are most advisable. If after initial drilling the beds are of shallow dip, vertical holes or holes of any angle can be used. The total cost of drilling a property is much greater if only vertical holes are used because more holes must be drilled to obtain the requisite information than when angle holes are used. Many tests for variation in angularity of a finished hole have seldom shown more than 2'; therefore, such tests may with safety be abandoned. Because the orebodies are generally about 100 ft. wide and cross a 40-acre tract at a slight angle, and as the dips are usually about 70"

Jan 1, 1925

By N. W. Perry

Some months ago a gentleman gave me a handful of minerals which he had collected in an arroyo, or dry stream-bed, that ran through the town of Ramos, State of San Luis Potosi, Mexico, as a sample of the class of ore that might be expected in the mines of that section. I was, however, familiar with those mines and their ores, and cast the pebbles aside as of no interest. I afterwards returned to Mexico and took charge of two groups of mines, one in the State of Zacatecas, and the other in the town of Ramos, State of San Luis Potosi. While I was thus engaged, it was a very frequent occurrence for parties to bring me specimens of rock, ores, etc., for my opinion on them; and one day a man brought me a half-dozen or more small pieces of a very black shiny mineral, desiring to know what it was. I did not recognize it, and desired him to give me the specimens for analysis, which he promised to do in a day or two. He never did give them to me, for he lost them ; but he said there were plenty more where these came from—at Ramos—and he could get them at any time for me. I thought no more of the matter until after my return to this country, when, one day, in looking over some of my old " trash," I came across the specimens at first referred to as having been cast aside so carelessly. I noticed two distinct minerals among the pebbles : one being erubescite or tetrahedrite, the predominating mineral of the mines of Ramos, and the other a hard black shining mineral, the same that I had wished to analyze in Mexico. On testing for hardness I was surprised that it scratched topaz with some degree of ease, thus placing it above 8 in the scale of hardness. Trying it with a corundum, I sometimes succeeded in scratching it, but at other times it would scratch the corundum, and at still other times neither would produce the slightest effect on the other. Crystallized topaz would be ground to a powder in attempting to scratch the black mineral, without abrading it in the slightest. It must, therefore, be placed at 9 in the scale of hardness. It is of the deepest opaque black, not unlike pitch-blende in ap-

Jan 1, 1884

By V. R. Garfias, R. V. Whetzel

It has been repeatedly questioned whether estimates of oil reserves are of any practical value, as the greater number of such calculations previously made have subsequently been proved to be grossly inaccurate. But even admitting partial justification for such statements, it must be evident that some idea, however approximate, of the available reserves of essential minerals—petroleum included—is of vital importance in mapping their development and the future trend of the related industries, particularly if it is kept constantly in mind that these estimates are not only never intended as a final word but must continually be subject to revision in accordance with the changes in their component factors. The value of these estimates, therefore, hinges on the clear understanding of what is meant by reserves and that the figures can only apply within the limited time when the controlling factors remain unchanged. It should be understood, further, that while estimates of possible and probable oil deposits are as a rule but idle conjectures, appraisals of proven oil reserves can undoubtedly be made with an ever-increasing degree of accuracy. And it is with this in mind that in the present study the endeavor has been to estimate only the world's proven oil reserves and to leave out of consideration the questionable volume of the probable and possible oil reserves. Such a survey presupposes further a clear distinction between the known amount of oil underground in proven fields at any one time, and the proven reserves: the portion that can be economically brought to the surface and made available for utilization. Only a fraction of the petroleum stored underground in proven fields— usually associated with natural gas—is or can be economically brought to the surface, and not all of the oik brought to the surface is economically utilized; also, although practically all the natural gas can be economically recovered and utilized, in actual practice a large part of the total volume that reaches the mouth of the well is wantonly blown into the air and wasted. It is thus estimated that in the United States only some 25 per cent of the petroleum stored underground in proven fields is actually brought to the surface; and in actual practice close to 25 per cent of the total gas produced is now absolutely wasted. And the dissipation of this

Jan 1, 1936

By Stephen H. Stow

A relationship exists between the color and the chemical composition of the pebbles from the Bone Valley Phosphate Formation. Darker-colored pebbles are relatively high in iron oxide and relatively low in calcium phosphate when compared to lighter-colored samples; the brown color of the phosphate pebbles can be correlated with their iron content and the black and gray colors with their organic carbon content.1,3 It was anticipated that the darkness of a phosphate sample might be quantitatively measured by a simple reflectivity test and that the amount of reflected light could be correlated with the chemical composition of the rock, especially with the elements which cause the color and darkness of the Florida phosphates. Twenty-one samples of production grade phosphate rock from Hillsboro County, Fla., were studied. All samples were ground to -200 mesh for reflectivity tests and analyses. All analyses are accurate to well within ±2% of the reported value, except for aluminum and organic carbon, which are accurate to only ±15% of the reported amount. Reflectivity measurements were taken with a model 610 Photovoltmeter for tri-stimulus amber, blue and green, and white lights. Experimental procedures and data are available upon request. Results Table 1 contains linear correlation coefficients (LCC) for the element-reflectance relationships for the samples. The top portion of the table refers to the LCC between the percent of light reflected off the samples and the percent of a given element (or its oxide) as analyzed. In the lower portion of the table the LCC refers to the relationship between the same reflectance data and the chemical analyses which have been corrected on the basis of 0% acid insoluble material (chiefly quartz) in the phosphate rock. Each LCC presented in Table I is computed for the 14 coarser samples exclusive of the seven concentrates since the concentrate samples appear to have anomalous reflectivities upon comparison with the coarser grades. Only the most significant LCC for each element is presented in graphical form. Discussion of Data Iron: [Fig. 1] is a graph of the relationship between iron and reflectivity (LCC = - 0.98). A good correlation with Fe2O3, is expected due to the relationship between the tan (or brown) color and the abundance of iron oxide, the principal mode of occurrence of iron in Florida phosphates.8 Note the location of the seven triangles which repre-

Jan 1, 1972

By R. W. Smith, G. W. Delamore, J. A. Spittle

RECENT work by the authors1 has demonstrated that the crystals constituting the equiaxed zone in small ingots originate, on quenching, in the chilled liquid. Whether any partial remelting2 takes place of the den-drites nucleated in the chilled region was not examined. However, the claim3 that this normally occurs, leading to crystal multiplication, has been disputed.4 Thus, for an equiaxed zone to form in the central region of an otherwise columnar ingot, it is necessary to transport crystallites from the chill zone to this region. In view of the work of Uhlmann et al.,5 it was considered desirable to examine the transport process further. Experimental Technique and Results. In the earlier experiments by the authors.1 a stainless-steel crucible 17/8 in. diam, 41/2 in. high, ad containing an alloy of A1-4 wt pct Cu, was quenched from 660°C into a bath of Wood's metal maintained at 100°C. Under these conditions a central zone of equiaxed crystals was obtained. However, if a 2250-G unidirectional magnetic field was applied for 2 sec immediately following the instant of quenching, or subsequently, the equiaxed zone did not appear. Careful thermal analysis showed that the short application of the field had virtually no effect on the thermal conditions of the melt. It thus appeared that the crystallites which were ultimately to grow large enough to form the equiaxed zone existed in the liquid immediately ahead of the interface, occlusion being prevented by the convective fluid flow induced by freezing from the walls of the cylinder. When this relative movement was prevented by the Lorenz forces induced by the application of the magnetic field, the crystallites were caught up in the rapidly advancing dendrite solid-liquid interface. To test this assumption, a small ingot of super-purity aluminum was partially melted and poured into a heated stainless-steel mold which was then immediately quenched into molten Wood's alloy. The resulting structure is shown in Fig. 1, and consists of columnar grains with a central fine-grained zone. Thus the unmelted solid present at the beginning of solidification had been transported ahead of the columnar interface. Discussion. There appears to be little or no information available on the interaction of suspended particles with a metallic solid/liquid interface. However, some information is available for transparent organic sys-

Jan 1, 1969

All the Technical PUBlications and Preprints published in 1932 are available at Institute headquarters. They are also on file in public, university and technical libraries and, when so indicated in the list, may be found in the Transactions. Copies of the Technical Publications have been mailed to those members of the Institute who are registered in the different classes: A-Metal Mining; B-Milling and Concentration; C-Iron and Steel Division; D-Nonferrous Metallurgy; E-Insti-tute of Metals Division; F-Coal Division; G-Petroleum Division; H-Nonmetallic Minerals; I-Mining Geology; K-Mining Administration; L-Geophysical Prospecting. Other members may obtain copies by writing to the Secretary. Copies of Preprints may also be obtained from the Secretary's office. Additional copies are sold at the rate of 1 cent per page; minimum charge, 25 cents. Nonmembers may purchase the papers at the prices mentioned. Metal Mining Technical Publi- Title Author Meeting Trans. cation Volume No. and Page* 484-A.45 Propeller Type Mine Fan at Moose A. S. Richardson New York 102, 88. 95 F.52 Shaft. Butte. Montana (13) Feb.. 1932 487-A.46 Progress in the Improvement of Max H. Barber New York. Methods and Equipment at Feb., 1932 Open-pit Iron Mines on the Lake Superior Iron Ranges (9) Pre. Sand Filling through Pipes and Lucien Eaton New York, 102, 33, 41 Boreholes (9) Feb., 1932 Milling And Concentration 445-B.37 Soap Flotation of the Nomulfides Will H. Coghill New York. H.19 (18) J. Bruce Clemmer Feb., 1932 461-B.38 Principles of Flotation—An Experi- I. W. Wark New York. mental Study of the Effect of A. B. Cox Feb.. 1932 Xanthates on Contact Angles at Mineral Surfaces (48) Iron and Steel Division 447-C.81 Electrochemical Potentials of Nitri- Shun-ichi Satoh New York, fied Steels (31) Feb.. 1932 450-C.82 Reaistanoe of Iron-aluminum Alloya N. 9. Ziegler New York. 100, 267. 670 E.143 to Oxidation at High Tempera- Feb., 1932 tures (8) 451-C.83 Pressure Welding of Low-carbon C. H. Austin New York. Steela with Theoretical Con- W. S. Jeffries Feb.. 1932 siderations on the Mechanism of Such Welding (42) 453-C.84 Inclusions—Tbeir Effect, Solubility C.E.Sims New York, 100, 154, 176 and Control in Cast Steel (24) 0. A. Lillieqvist Feb., 1932

Jan 1, 1932

Gerald Sherman, Bisbee, Ariz. (written discussion*) .—The fact that, after a change in the hours of labor, as much work is found to be done in 8 hr. as was accomplished in 10, probably results from the more rigid examination of operating methods that is made when the management faces new and more difficult conditions. Although A better working pace will prevail, most of the gain will result from economies of plan and only a part of it from the improved effciency of labor. The Iabor of shoveling is so severe that it may be easily believed that a working period of less than 7 hr. will give maximum results, but there arc many other occupations about a mine in which this is not true, and in which the rate of accomplishment is in proportion to the time employed, up to 9 or 10 hours. Mr. Harley's study of shoveling has becn thorough, and demonstrates the benefit of investigation and education even in such simple work, but his reference to methods of payment opens a subject even more important in mine management. The efficiency of labor may be excellent, but unless a method of equitable payment accompanies it, the result will be only temporary. With strict but sympathetic supervision, a good average day's work can be obtained; but with the exception of those unusual men who cannot be restrained from working to their limit, an average daily wage does not bring out the remarkable performance of which many men are capable. There is also a considerable variation in the average amount accomplished, dependent on the supply of Iabor. This can readily be shown by any labor record that covers several periods of shortage or superabundance of labor. An increase in the daily wage in the time of labor shortage does not necessarily bring out an increased day's work; there is usuaIly a decrease in labor efficiency at such times regardless of the wage, whenever a daily rate is used. Rewards to individuals for exceptional performance appearing as an increased rate of pay cannot be made in a large organization without bad feeling. In a small organization, an individual's ability may be so well recognized that different rates of pay can be applied. Exceptional work can only be obtained by a method of payment based on the valuable results accomplished. As a basis for such payment, an

Jan 1, 1920

IDO not want to omit anything in which fire or its operation has a part, if I know or can tell it, and have already told you so many other useful, powerful, and ingenious effects (finally of powder and other' fire deadly and very injurious to all living things, indeed, composed for the destruction of those who possess it as well as those who do not) but I do not want the end of my writing to be in tragedy. Therefore I wished to tell you how, from these fires composed of forceful and horrible mate¬rials bringing harm and terror to men, a happy and pleasing effect is also produced and, instead of fleeing from it, the people willingly go to see it. Among others I remember that it was once customary to use these in Florence and in Siena, more than elsewhere. The chief feast day celebrated. by one of these cities is the day of the birth of Saint John, and the other is the Assumption of Our Lady, on the fifteenth of the month of August. In the morning they visit the shrines with great devotion and solemnity, displaying their pomp as much as possible, and later they hunt lions, wild bulls, untamed horses, and many other animals. In the same public squares there was also erected as a decoration an edifice fixed in the ground in the middle of this space, or hanging from a heavy rope crossing between the loftiest points of equal height that could be found in that place. This they have done and still do, and perhaps in time to come will continue to do when opportune. This structure was usually of wood; indeed it is necessary that the latticework of its construction be made only of this. It was covered and en¬larged by tying and fastening hay on top to bring it almost to completion and then papier-mâché was applied. [165v] The figures were first appropriately painted and made of a combination of vessels one above the other, developing various decorative figures in relief which should represent some fable or history and should not appear haphazardly made or without understanding. Now the master proceeded to arrange these figures in a composition according to his skill or art of design, and likewise planned

Jan 1, 1942

By B. Chalmers, S. Wojciechowski

THE structure of the equiaxed zone of several A1-Cu samples mechanically stirred during unidirectional solidification was examined. The stirring was produced by rotary oscillation of the mold about its vertical axis.' It was found that in Some samples the structure is not of the same type over the whole of the equiaxed zone; it consists of regions with two different etching responses. Fig. 1 shows this structure in a Al-1 wt pct ku sample. The lighter etching regions with a coarse structure form something like a network and the darker etching regions with a finer structure can be observed as the continuation of the coarse structure inside this network. The difference in size and shape of the dendrite branches (they are rounded in the coarser structure) is similar to that found by Williamson and Chalmers in ice crystals solidified in undercooled water: when the amount of undercooling was small, the ice crystals were more rounded and coarser than these solidified with a larger amount of undercooling.' It seems justified to conclude that the observed structure resulted from solidification under different thermal conditions: the coarser structure solidified first out of the "purer" liquid and with a smaller amount of undercooling and the finer was formed later out of solute-enriched liquid under conditions of much more rapid heat extraction. A considerable change in the heat flow conditions at the later stages of solidification can be easily understood by taking into account that the coarser crystals form a continuous network and the amount of trapped liquid is relatively small; hence the contribution of latent heat is much smaller in the later stages of solidification. The difference in structure and etching characteristic reflects a difference in composition between these two regions. It was found that the darker etching re- gions are harder (30.4 to 31.3 HV5) than the lighter etching ones (25 to 26 HV5). A similar type of structure was found in a A1-4 wt pct Cu sample grown by Czochralski method. Fig. 2 shows the structure in the lower part of a sample grown slowly and then decanted by a rapid removing of the sample from the melt. In a few places trapped liquid solidified in the same manner as in the sample shown in Fig. 1.

Jan 1, 1968

By C. K. Leith

Conservation, narrowly and strictly considered, means the preservation in unimpaired efficiency of the resources of the earth; or in a condition so nearly unimpaired as the nature of the case, or wise exhaustion, admits. And broadly considered, it means more than the word itself implies, for it naturally includes an examination of methods whereby the natural inheritance of the human race may be improved; and still more broadly considered. and as used in popular discussion, it includes a treatment of the effects of productive conservation methods upon distribution. "Conservation means a sacrifice of the present generation to the future generations whenever it is carried too far. There is a sharp limit to the economic sacrifice that we may reasonably ask the private person to make for even the present welfare, and the limit is still sharper when we come to consider the interests of future generations." In a paper on the iron ores of America, presented to the Pan-American Scientific Congress at Washington, I have emphasized the fact that the reserves of iron ores in the two Americas are enormously in excess of the requirements of the present generation, in fact, so large that no shortage is to be anticipated for many generations in the future; that a large part of the value of iron ores is put into them by man's efforts to make them available. This fact is fundamental for the intelligent consideration of policies of conservation as applied to iron ore. As I interpret it, this fact makes it practically unnecessary that the present generation should make any especial sacrifice for future generations in the way of conservation of its iron-ore resources. Even if we were disposed to look forward to a period of 100 or 200 years, with a view to insuring the welfare of the people living at that time, it is doubtful whether any procedure we could now formulate would materially help them in the matter of iron ores, so large are the reserves available. In order that an appeal for conservation may be effective it must obviously favor the welfare of the present or immediately following generations; it must promise benefits to general and individual welfare during a period within the range of comprehension of the average man.

Jan 1, 1916

He was born at Montreal, Canada, in 1875. His earliest education was received in Montreal hut was continued from 1885 to 1892 at schools and academies in Brooklyn, Whitestone, and Flushing, L. I. For his technical education he returned to McGill University, where he graduated in 1897. His first professional occupation was as transitman enga.ged in the running of township lines in the Rainy River District of Ontario. In 1899, he was made assistant chemist at the Cuggenheim smelter at Aguascalientes, Mexico. From 1900 to 1903, he was chief chemist for La Compañia Minera de Peñoles, at Mapimi, Durango. We have no information as to his pursuits during the next eight years, but from 1911 until 1914, when he became a member of the Institute, he was chief engineer for the Bankhead mines in Alberta, Canada. Lieutenant-Colonel Alfred Winter Evans Lieutenant-Colonel Evans, who was in command of the Third Battalion of the New Zealand Rifle Brigade, and had been cited in Distinguished Service Orders and received the Distinguished Conduct Medal, was killed in action on Oct. 12, 1917. Alfred Winter Evans was born in Natal, South Africa, in 1881, and received his preliminary education in the Durban High School. For the next five years he attended St. George's School at Harpenden Heights, England, until 1898. Returning to South Africa, he worked . for three months of 1898 as underground sampler for the Crown Deep Gold Mining Co., at Johannesburg, and for six months of the following year he was shift-boss for the Crown Deep, Ltd. At the outbreak of the Boer War he took an active part and was engaged on military service from 1899 to 1902. At the close of the mar, he came to New York and attended the Columbia School of Mines, where he graduated with the degree of E. M. in 1906. A part of that year he spent as assayer to a mining company at Poland, Arizona. In 1907, he returned to South Africa and engaged as underground contractor in charge of mining and development at a number of the South African mines, notably the French-Rand, the ViIIage Main Reef, the City Deep, and others. In 1908, he acted as shift-boss for the Fer-rerra Gold Mining Co. at Johannesburg. In 1909, he was appointed acting general manager for the Consolidated Goldfields of New Zealand,

Jan 1, 1920