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By AIME AIME

ELECTRICAL methods of geophysical exploration attracted major attention at the three sessions devoted to geophysics on Monday and Tuesday. At the opening' meeting Monday morning Hans Lundberg gave the paper by himself and Folke Kihlstedt; he described the use of the Racom, discussed last year, and the method whereby it is possible to eliminate all but subsurface, effects in electrical exploration. In the discussion Theodor Zuschlag pointed out some of the theoretical considerations behind the field procedure. Karl Sundberg's paper on the effect of impregnating waters was presented by title only, and S. F. Kelly then gave an abstract of a paper on the electrical properties of ores, by J. J. Jakosky, R. N. Anderson and Clyde H. Wilson. , This dealt with an exhaustive series of laboratory tests on the variation of -conductivity of ore specimens with the frequency of the energizing current, and of the effect of moisture content in typical clays and gouges on their conductivities at various frequencies. Considerable discussion was provoked during which the authors came in for some-criticism on their measuring circuits and for their assumption that a solid conductor could be compared with linear ones. They were praised, however, for making a start toward a compilation of resistivities for ores and rocks. Dr. Slichter disagreed with them that the conductivity of an orebody was primarily capacitive. He also called attention to the fact that it was high time geophysicists adopted the standard physical expression of ohm-,centimeters or ohm-meters to express resistivities. This same point was the burden of the next paper,. "Uniform Expression for Resistivity," by Sherwin F. Kelly, presented by title only.

Jan 1, 1932

THE Fall Regional Meeting of the Institute, which has now for some years been held in cooperation with the Western Division of the American Mining Congress, will be held this year at Joplin, Mo., in the heart of the great Tri-State district. This year the Tri-State Zinc and Lead Ore Producers Association is joining in the meeting. The Society of Economic Geologists will also take part though not offering any papers. The district in which the meeting is held includes adjacent parts of Missouri, Kansas and Oklahoma. Out in the heart of a fertile prairie farming country, it is one of the major mining districts of the world. It produces normally approximately one-third of the zinc ore mined in the United States which is equivalent to nearly one-half the zinc since the concentrate has always been notable for the height of its grade. Even in the depressed business year 1930, the American Bureau of Metal Statistics credits the district with 434,460 tons of concentrates equal to 217,230 tons of zinc out of 1,503,095 and 576,630 respectively for the country as a whole. This was equal to about one-seventh of the world's output of zinc, more than that of any foreign country. In addition about 75,000 to 100,000 tons of lead is annually furnished by the same mines. Elsewhere we present a general description of the district prepared for this meeting by J. C. Heilman, a Lehigh graduate, who has spent the past eleven years there and has had charge of explorations for many of the companies.

Jan 1, 1931

By C. Feng, C. Elbaum

Knoop hardness measurements were carried out on large grains of iodide titanium containing different amounts of oxygen. For each oxygen content the hardness is recorded ainingas a function of the crystal orientation and of the angle 4 between the indenter diagonal and the projection of the C (hexad) axis in the surface. The results can be expressed by the following relation; hardness = n-k cos 2ø, where n and k are constants for a given oxygen content and crystal surface orientation. A NISOTROPY of hardness is a well-known phe-nomenon and has been reported for many metals.1-3 At the present time, however, such information is not available in the literature for titanium. Consequently, a systematic study of the simultaneous effects of oxygen content and crystallographic orientation on the hardness of titanium was undertaken in this laboratory. Evaluations of oxygen content in titanium are frequently carried out through hardness tests. Although such procedures may be justified in small grain specimens, the results of the present investigation indicate that the anisotropy of hardness should be taken into account in the case of coarsegrained specimens as well as in the case of pronounced preferred orientation. Materials and Experimental Procedures Iodide titanium, 99.99 pet pure and containing of the order of 0.002 wt pet O, was used throughout this investigation. The metal was arc melted in an argon atmosphere and cold rolled into strips 1/16 in. thick. These strips were subsequently recrystal-lized and strain annealed in vacuum (10" mm Hg or better) at 850°C in order to produce crystals varying in diameter from 10 to 25 mm. Oxygen was introduced into selected large crystals by heating at 700°C in an atmosphere of pure oxygen under an observed pressure of approximately 50 mm Hg. Each sample was subsequently annealed in vacuum at 850°C for 100 hr, in order to homogenize the oxygen content throughout the specimen. It was found that longer annealing was not necessary, for no change of surface hardness in a given direction was detected after prolonged annealing. The oxygen content was determined by the difference in weight of the specimens before and after the oxidation-annealing cycle. The accuracy of oxygen determination is within ±0.1 mg in samples weighing 0.5 to 1 g. A vacuum fusion analysis of oxygen was performed on several samples and gave results in good agreement with the ones obtained by the weight change. It should be emphasized that expected weight losses through evaporation of the metal in vacuum at 850°C' are many orders of magnitude lower than the precision of these measurements. Following the annealing treatment, both oxidized and unoxidized crystals were carefully polished. All detectable traces of surface cold working were removed by repeated polishing and etching. Laue back reflection X-ray patterns were taken for each crystal for the purpose of determining the orientation and ascertaining the absence of substructures detectable by this method. Hardness measurements, using a 1 kg load, were subsequently carried out on a Tukon hardness tester equipped with a Knoop indenter. The Knoop indenter was used throughout this work because indentations obtained by means of a Vickers indenter are considerably distorted due to the anisotropy of the elastic constants in titanium. Such distortions are much less pronounced in the case of Knoop indentations, although for some orientations a cer-

Jan 1, 1959

The following resolution was prepared, by the War Minerals Committee and was submitted by it to the Board of Directors of the American Institute of Mining Engineers, asking that it be passed by the Board and used to the best advantage to secure the end desired. WHEREAS, the steel industry of the United States is almost entirely dependent on the importation of foreign manganese ores, the consumption of which for the year 1918, it is estimated, will exceed 850,000 tons; and WHEREAS, the ships now engaged in transportation, especially from Brazil, are needed with ever increasing urgency for supplying our Army and Navy forces abroad; and WHEREAS, much shipping may be spared from manganese transportation and the domestic sources of manganese may be utilized, provided the steel manufacturers of the United States will cooperate to this end by taking advantage of the possibility, in open-hearth and Bessemer practice, of so called "residual" manganese, and by using spiegeleisen instead of ferromanganese, thereby following the example already set by three large and prominent steel producers; BE IT RESOLVED, that the Board of Directors of the American Institute of Mining Engineers urges the steel manufacturers of America, for patriotic reasons, to give immediate consideration to the development and utilization of domestic manganese ores; to use no ferromanganese, except for the manufacture of grades of steel below 0.15 per cent. carbon, to use domestic ores whenever possible in place of the high-grade imported ores; and to urge their associates and colleagues in this and other possible ways, to vie with one another in releasing ships for importation of any materials that cannot be secured or produced in this country.

Jan 1, 1918

National Society of Professional Engineers has thrown its full sup- port behind pending legislation to appropriate $500 million for national conversion efforts that would provide employment opportunities for engineers, scientists, and technicians who are currently unemployed because of the decline in defense and aerospace programs. Known as the Davis-Giaimo bill, the proposed legislation would raise total Federal investment in science and technology to an adequate annual spending level and keep it proportionally equal to the growth in the GNP. If passed, the bill would increase and maintain Federal obligations for civilian-oriented research and development activities to a parity level with similar obligations for defense research development. U. S. Bureau of Mines has cataloged and placed on open file an inventory of U.S. coal deposits which can be economically strip mined at today's production costs. The costs include charges for reclaiming the mined land as required by 21 states. The report claims that some 46 billion tons of bituminous coal and lignite can be strip mined under present economic conditions, and that 32 billion tons of the total is classified as having less than 1% S. The report reviews strippable coal deposits by state, by county, by coal seam, by coal-seam thickness and by sulfur content. The report also gives an up-to-date summary of state laws on surface mine reclamation. Open-file copies of "Strippable Reserves of Bituminous Coal and Lignite in the U.S." may be consulted in Washington, D.C., at the Department of the Interior library and at U.S. Bureau of Mines offices in Pittsburgh, Denver, San Francisco. Dallas. Spokane, and Douglas Island, Juneau. Alaska.

Jan 1, 1971

Editors of engineering periodicals usually read the advertising pages. It may be hard' for some men, let alone engineers, to understand what value there is in reading "dry advertisements." Yet it is a fact that valuable suggestions have been obtained from these so-called "dry advertisements" which have been the means of securing greater efficiency in the performance of some undertaking and consequent saving of time and money. It seems to be an editorial practice to look to the advertisements for suggestions for the reading pages. It is a fact that some of the most appreciated descriptive articles were suggested by advertisements. Every undertaking is limited to that point where tools and machinery for its successful performance and completion may be purchased or manufactured. No work can he planned without having in mind such limitation, and the technical journals may be relied upon to furnish descriptions, both editorially and through the advertising pages, of methods and plant used in successfully performing various tasks. This being so, why should not the reader or subscriber to a magazine or periodical avail himself of such a fountain of knowledge? Such perusal proves of value to the up-to-date engineer or man occupying a -position. of responsibility where initiative is essential. Authorities agree that advertisements are on a par with technical articles for their educational value, and this Is as it should be. Also, most subscribers to a publication realize that a, successful advertising medium means a continuance of advertising patronage, which in turn enables the publisher to turn out a better and larger volume of reading matter.

Jan 6, 1915

By Albert Hahn

ABOUT three years ago John Hays Hammond took over the control of the Eureka Metallurgical Co., at Salt Lake City, Utah. Funds were advanced for investigating the process invented by R. V. Smith, for concentrating oxidized lead ores. A great deal of laboratory work was done and a reagent was developed by C. M. Nokes of Salt Lake, which was found to be particularly suitable for oxidized copper ores, refractory manganese silver ores, and oxidized gold ores. After sufficient laboratory work had been performed to demonstrate the fundamental principles of these inventions, a test mill, having a capacity, of 20 tons of ore daily, was erected at Murray, Utah. In this test mill approximately 1200 tons of various types of ores have been concentrated by means of the above-mentioned process and reagents, and this large-scale work as well as laboratory work is being continued at present. Details of these mill tests are given in Table 1, and a representative group of laboratory tests are shown in Table 2. The process requires no special machinery or appara-tus. Its success depends entirely, on the method of preparing the pulp and its subsequent flotation in clean water, as outlined in the Smith patent. The reasons for the success of the Nokes special reagent are not definitely known. The outstanding feature, which seems to be of extreme importance, is that when the concentrates are examined under the microscope, each particle of mineral appears to have a particle of paraffin, attached to it. This paraffin-mineral combination seems to be particularly suitable for flotation and it follows that any coating oils readily attach themselves to the paraffin-mineral combination.

Jan 9, 1923

By Duane H. Haley

Dr. F. Well, the first thing that you have to realize is what is the Bureau of Mines? The Bureau of Mines basically has two functions. First it does the research and development relating to mining, processing, conversion, refining, recycling and substitution for minerals and materials. We work hand in hand with the U. S. Geological Survey on the geological end, although the exploration part of the game is theirs, and there is a very good relationship between the Survey and the Bureau of Mines. There are some overlaps with the Office of Coal Research, and we expect to be able to straighten out the areas of overlap, because it's important than OCR and the Bureau work together. Both the Office of Coal Research and the Bureau of Mines will have increased budgets next year, assuming that they are appropriated by the Congress. The other general area is in the whole area of mineral policy. The Bureau of Mines again is the key agency for developing data and analyses and making recommendations on all types of mineral policy in the Federal Government. It's a focal point for all types of minerals activities. It's the only real centralized focal point, along with the USGS, in the whole Federal Government. The problem areas, to answer your question specifically, are first of all the Bureau of Mines budget this year is $105 million and the budget for next year is $215 million, so it's more than double. Now, assuming that this budget is appropriated by the Congress, most of that money will be used for research and development in the energy area.

Jan 4, 1974

By Alan U. Seybolt

UNLIKE its sister elements, columbium (niobium) and tantalum, vanadium has not been available until recently in fabricated form. While Vanadium Corporation of America has offered the metal in fairly pure form for sale for many years in small lots for research purposes, this grade of vanadium has been brittle, probably because of a high oxygen content. Hence, when in 1950 the announcement1 was made that wrought vanadium was available as a commercial material, this represented a large step forward in the metallurgy of vanadium. While vanadium is generally regarded as a rare metal, data on its occurrence in the earth's crust show it to be as abundant as copper, zinc, and lead combined. Vanadium is widely distributed, but it does not seem to occur in massive deposits except in a few localities, principally in Colorado, Utah, and Arizona, where it is found in sandstone formations, and in Mina Ragra, Peru. Only in Colorado or Peru are ores mined solely for the vanadium content. Ores in the United States are principally carnotite and roscoelite; the former is of particular interest because of its uranium content. It is a uranium-potassium vanadate containing approximately 52 pct of UO2 and 18 pct of V2O5. Production in the United States during the war years averaged around 2000 tons a year, but dropped to 636 tons in 1946. In recent years, ferrovanadium has been selling for about $2.80 per pound of contained vanadium. This suggests that the price of the pure metal will never be as low as $2.80 per pound, but it could

Jan 1, 1953

By Alan Stanley

R. T. Hukki (Finland Institute of Technology, Helsinki, Finland)—In the analysis of mill products containing minerals of appreciable difference in specific gravity the well-known principle of the method described by Stanley is applied in a number of ways for a variety of problems. The use of Le Chatelier bottle as explained in the paper may be a dependable and sufficiently accurate way, although no information is given as to the reproducibility of the specific gravity determinations. In the case of MacIntyre ore the method is applied for three separate products produced apparently without reagents and relatively free of fine slimes. Should it be applied for flotation products carrying a substantial amount of slimes, difficulties should be anticipated in the process of eliminating air inclusions from the sample. The difficulties mentioned above may be overcome by the use of a volumeter, an instrument designed for specific gravity determinations of finely divided solids in dry state. This instrument, see Fig. 4, is manufactured by F. Süffert-Bürner A. G. in Basel, Switzerland. Its operation is based on the law of Boyle and Mariotte. With the use of the volumeter, the specific gravities of test samples having a total volume of about 30 cm are easily reproducible within ±2 units in the second decimal of the specific gravity figure, and even better than that with utmost care. This accuracy is sufficient for ordinary operational control. How closely the specific gravity determinations follow the respective chemical assays depends primarily on the nature of the sample itself. In this respect no specific gravity instrument can give better results than those justified by the consistency of mineral distribution in samples analyzed.

Jan 1, 1954

By Frederic Benard

THE treatment of Balbach-Thum slimes at Copper Cliff by the Ontario Refining. Co. is of interest because it differs considerably from methods usually employed for the recovery of fine gold from parting-plant slimes. Owing to the comparatively high percentages of pal-ladium and platinum, wet methods are used to remove the greater proportion f these metals before electrolytic refining in the Wohlwill cells. THE PLANT The platinum-metals department, Wohlwill room, and gold-melting room extend along the north side f the silver refinery and are separated from the parting plant by a glass partition (Figs. 1 and 2). The platinum-metals department resembles a laboratory built on a large scale, with the various pieces of equipment laid out on terraces to facilitate handling. Because of the corrosive nature of the solutions, chemical stoneware is used throughout. Elevation of acids is accom-plished by means of Mariotte bottles. On the top level are three steam-jacketed stoneware kettles of 50-gal. capacity, also a packed tower. One kettle is used for digesting the slimes while the remaining kettles are used for precipitating the gold. The dissolver is equipped with a treated concrete hood, which is connected to the flue system. Gases are drawn off through the packed tower by means of a 6-in. stoneware exhaust fan. A 15 per cent solution of sodium carbonate is continually circulated through the tower. On the intermediate level are two suction filters, one for removing silver chloride and the other for the gold sand. The filter medium consists of an asbestos pad covered with a filter paper on which is a layer of twill.

Jan 1, 1938

By J. R. CAIN

SAMUEL L. HOYT, ? Nela Park, Cleveland, Ohio (written discussion?). The work that Dr. Cain is doing on gases in steel should have a highly important bearing on investigational work in connection with steel-making practice. We found, for example, in our work in connection with the use of manganese in open-hearth practice that we needed expressions for the manganese efficiency and the "condition" of the steel. To get these figures we assumed that we would need to know the amount of FeO at different stages of the heat and the amounts of the gases present. This required simultaneous analyses of our samples for FeO and the gases and Dr. Cain seems to be the only investigator who has considered the analytical work from this point of view. That he has done so is very encouraging and it is to be hoped that his work will solve the mys-teries now surrounding this neglected phase of steel metallurgy. Those interested in the Ledebur method for use in connection with the efficiency of manganese as a "deoxidizing " agent will he disappointed to learn that more recent work at the Bureau indicates that Ledebur determinations are not reliable. The principal source of error seems to be due to the partial reduction of the ferrous oxide by the carbon present in the steel. However, it seems like an unnecessary criticism of the Ledebur method to state (p. 1319) that it proved of little value because it showed little differences in oxygen for a series of steels treated with ,various reagents and showing variations in physical properties and free-

Jan 12, 1919

E. R. Rice, Wickenburg, Ariz. (communication to the Secretary*):—While this paper is primarily intended as a discussion of Mr. Riter's, I think it will be best to indicate my criticism by describing my own field-methods. It has been my experience that, for ordinary work, the regular transit-book is to be preferred to the card-system for recording notes. This is specially true when computations in the field are required, for it is then necessary to have at hand the total latitudes, departures, ancl elevations. Moreover, the transit-book is easier to carry and manipulate in wet or cramped places, and is not as liable to damage as the loose leaf or card. I use a regular transit-book in the field, and then copy my notes, sketches, etc., in an o5ce-book, entering also the latitudes, departures, and other reductions. These values are then copied into the field-book, securing a duplicate record, in case either book should be lost or mislaid. In the field-book, the notes are entered on the left-hand, and the sketches and remarks on the right-hand page. The next two pages are left blank for the latitudes, departures, bearings, reduced distances, etc. Of course, the notes for the different parts of the mine are entered in the field-book in the order in which they are surveyed; but in the they are entered systematically. It has been my experience that the system of keeping notes used by a surveyor, is particularly adapted to the needs and temperament of the individual. Otherwise, he would not be

Jan 1, 1912

By R. W. Titshall

WHAT IS SAMPLING? We are all involved in sampling almost every day of our lives, by tasting, feeling, or smelling. Most raw materials, food products or manufactured items are sampled several times at various stages of the production process before a commodity of suitable quality can be produced. Data obtained from sampling is used in establishing price, quality control, allocating production costs, or overall process efficiency. The area of sampling outlined in this article is the collection of a small quantity of material from large continuous bulk flows of solids and slurries. The concern in obtaining the sample is that the material obtained is truly representative of the main flow in every respect. The methods and equipment outlined are for the collection of a manageable sample. The sample has to be analyzed in a laboratory to determine its characteristics and compliance to set standards. SELECTING A SAMPLING SYSTEM When selecting a sampling system, it is essential to define the requirements, as to what the actual sample obtained will be used for and what degree of precision is required. Determine whether or not the system has to comply with any set standards such as A.S.T.M. (American Society for Testing and Materials) which have established methods for collection of a gross sample of coal. Sampling which is done for in-plant or process control is not generally governed by set procedures, but similar care should be taken during the selection process so that when the equipment is put into service it will operate reliably and produce a sample which is truly representative of the total material lot or consignment.

Jan 1, 1982

By M. J. Salkind

In order for fiber composite materials to find extensive use in structures, it is necessary to develop techniques for joining these materials. Riveting and adhesive bonding are two possible techniques which have been investigated although the former is less desirable because the low shear strength of most matrices makes this type of joint subject to bearing failure. Welding is an effective means of joining, especially for high-temperature applications where ad-hesives are weak; however, there are significant limitations placed on welding composite materials. The commonly used fusion welding techniques will find less use for joining composites because the two phases are often unable to stand exposure to such a stringent environment. In the case of eutectic composites, fusion welding will completely destroy the controlled microstructure. Solid-state techniques such as diffusion bonding offer potential success with certain design requirements placed on such joints. Since the primary mechanism of load transfer from matrix to fiber is shear parallel to the fibers, little load can be transferred across a butt-welded interface perpendicular to the aligned fibers. Successful joint designs must have a component parallel to the fibers to allow a shear area for load transfer. Configurations such as lap and scarf welds are likely to be successful. This note describes some results of experiments with diffusion-bonded joints in A13Ni whisker-reinforced aluminum. The composite material, prepared by unidirectional solidification of the A1-A13Ni eutectic, is described elsewhere.'-' It consists of aligned micron size whiskers in a matrix of aluminum. Since it has been shown that the microstructure of

Jan 1, 1969

By L. P. Teas

In spite of the influx of operators into the Gulf Coast anxious to retrieve their depleted production in other fields, and in spite of very active application of the most scientific geophysical methods to locate new producing areas, the results have been very discouraging and the year has failed to produce more than the average results for a Gulf Coast year. During the year seven new oil fields, some of which are still of very little importance, and one new gas area have been discovered. These fields are Tom Ball, Greta, Cleveland, Raisin and Garwood in Colorado County; Louise and Premont in Jim Wells County, and the new producing gas area near Ace in southern Polk County. During the year salt has been found for the first time at Carlos and Esperson. New producing areas have been developed on East Stratton Ridge, Hockley, Hull, Port Neches, near Pettus in Bee County, and on the O'Connor Ranch in Victoria County. The total production for the Gulf Coast for the year was 62,837,435 bbl., an increase of 18,589,000 bbl. over 1932. During the year, 1307 wells have been drilled of which 207 were wildcats, compared with 653 wells and 141 wildcats the previous year. The total daily production at the end of the year was 165,201 bbl. At present there are 3100 oil wells producing. The average production per well is 55.5 bbl. per day. The price of crude fluctuated considerably during the year, beginning at 80c per barrel and closing the year at $1.04 per barrel. Completion data for 1933 are as follows:

Jan 1, 1934

By L. Douglass Anderson

Fox some years past the annual reviews of the metallurgy of lead have almost uniformly stated that there have been no great changes, such as there were, being more particularly noticeable in the refinement of details. While this is quite true, nevertheless these changes in details are gradually bringing about a condition that, taken as a whole, constitutes a considerable advance in the art. Local circumstances have often -compelled metallurgists to adopt certain peculiarities of practice which -upon trial have been found advantageously applicable to more than the restricted district f origin. This paper will deal ' with some of the more novel features developed in recent years at the United States smelter, Midvale, Utah, particularly with reference to the influence of the bag house. The plant is equipped with six blast furnaces, 48 by 160 in., mechanically fed; four Wedge furnaces for roasting matte and sulphide ores; four Dwight-Lloyd sintering machines; 20 converter boxes for blast roasting; storage bins for ore, fuel, and fluxes; "oxide" and "sulphide" sampling mills; bag house taking all the gases of the plant; arsenic plant for treating the dust gathered there; laboratory, shops, etc. The most marked feature of the plant is its complete bag-house system. Of the many schemes thus far tried for preventing damage to surrounding agricultural interests the writer is aware of none as yet quite as efficient as the bag house. A common remark of visitors upon approaching the plant and viewing the clear stacks is that it appears to be shut down, whereas once inside all the evidences of industry are found.

Jan 7, 1914

By L. Douglass Anderson

Fox some years past the annual reviews of the metallurgy of lead have almost uniformly stated that there have been no great changes, such as there were, being more particularly noticeable in the refinement of details. While this is quite true, nevertheless these changes in details are gradually bringing about a condition that, taken as a whole, constitutes a considerable advance in the art. Local circumstances have often -compelled metallurgists to adopt certain peculiarities of practice which -upon trial have been found advantageously applicable to more than the restricted district of origin. This paper will deal with some of the more novel features developed in recent years at the United States smelter, Midvale, Utah, particularly with reference to the influence of the bag house. The plant is equipped with six blast furnaces, 48 by 160 in., mechanically fed; four Wedge furnaces for roasting matte and sulphide ores; four Dwight-Lloyd sintering machines; 20 converter boxes for blast roasting; storage bins for ore, fuel, and fluxes; "oxide" and "sulphide" sampling mills; bag house taking all the gases of the plant; arsenic plant for treating the dust gathered there; laboratory, shops, etc. The most marked feature of the plant is its complete bag-house system. Of the many schemes thus far tried for preventing damage to surrounding agricultural interests the writer is aware of none as yet quite as efficient as the bag house. A common remark of visitors upon approaching the plant and viewing the clear stacks is that it appears to be shut down, whereas once inside all the evidences of industry are found.

Jan 7, 1914

By W. J. Feuerstein

STRUCTURAL imperfections in crystals, in recent years, have received the attention of metallurgists concerned with single-crystal properties. Certain etching solutions cause local variations in the rate of etching at dislocations.' Dislocations are expected to be preferred segregation sites for impurities' and Dash" has shown that precipitation of copper occurs preferentially at edge-type dislocations in silicon. Diffusion rates along dislocations are probably higher than rates through more perfect crystalline regions.' These and other phenomena which may be influenced by dislocations may be studied by revealing dislocations as etch pits. This study was undertaken to develop an etch solution for silicon crystals to reveal low-angle grain boundaries associated with dislocation arrays and also etch pits with good contour definition. Additional etches have been reported by Dash," Vogel and Lovell.T rystals were sectioned on crystal lographic planes at various angles from the growth direction for microscopic examination of the etch pits. Experimental Crystals of 75-100 g mass and 3 cm diam were oriented and cut on crystallographic planes. Crystals were grown by Czochralski technique from a quartz crucible. Lapped wafers were chemically polished in a modified CP-4 etch for 1 min (bromine was deleted from the etch solution). The polished wafer was then etched* at room temperature for 5 min. The use of larger amounts of H2O and/or CH2COOH slows the reaction. The Cu(NO3),.3H2O was added to increase the reaction rate and give more definition to the etch pits developed. Some pertinent features concerning the attack of this etch on silicon can be summarized as follows:

Jan 1, 1959

By Edward Steidle

IT has been said that "the command of nature has been put into the hands of man before he knows how to command himself," and what we see about us gives particular emphasis to this observation. If this condition be granted, the vaunted boast of school and college, of the institution that had the training of this generation, and of its fathers, and of its grandfathers, the boast that education is a "preparation for life," stands exposed as a hollow claim, or as a ghastly, cynical conception of life, or else education has fallen far short of its intentions. It has been evident for some time that education was not meeting the fullest expectations of society. In recent years there has been a deal of speculation indulged in by both laity and faculty in regard to American education and American civilization, and some few and sporadic changes have been effected. Today, however, there is no longer time for mere hypothetical considerations; we are faced with certain definite facts and confronted with obvious conditions that will not wait for fine-spun theories. If educators do not put their house in order, someone else will do it for them. The trends in mineral industries education must be in harmony with this general realignment that is today visible on the educational horizon, and only as these trends are in conformity with this movement can they be called sound. Two questions, then, confront mineral industries educators: (1) What are the trends in mineral industries education, and (2) how do these trends correlate with the major educational movements of the day?

Jan 1, 1933