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By Bruce R. Lipin

Chromite, the only ore of chromium, occurs almost exclusively in mafic-ultramafic rocks and their weathering products. However, not all kinds of mafic-ultramafic rocks are favorable hosts for possible low-grade chromite deposits. For instance, chromium-bearing basalts are not favorable because they commonly contain <0.3% Cr203, and chromite is almost always less than 50 mp in diameter, if it is present at all. Chromite-bearing ultramafic rocks in stratiform and alpine complexes tend to be either ore grade (>25% chromite) or very low grade (<2% chromite); intermediate rocks are scarce. In most complexes, large tonnages exist only in the <2% chromite rocks and the composition of the chromite in those rocks may be unsuitable for metallurgical use. Some nickel laterite districts contain more than lo8 tons of material with 2.0 to 5.5% Cr203, and hence, chromium could be a byproduct of nickel in some laterite districts. In addition, some chromiferous sand placers may contain tens to hundreds of millions of tons of material between 2 and 5% Cr203

Jan 1, 1983

By Walter Harvey Weed

introduction,.............715 "WHY ORE-DEPOSITS ARE Common about Igneous Contacts,. ..716 Outline of a Genetic Classification OF Ore-Deposits,.. .. 717 Ores of Igneous Origin.. .. .. .. .. 717 Igneous-Emanation Deposits........ 719 Fumarolic Deposits..........719 Gas-Aqueous Deposits.........719 Deposited by Meteoric Waters ........720 Contact Metamorphic Deposits.........720 Classes of Deposits......... 731 Contact Zones..........722 Character of Gangue..........722 Character of Ore-Deposit.........723 Literature...........724 Geographic Distribution.........724 Copper-Deposits—Cananea Type......725 British Columbia—Boundary District....725 Mexico..........727 Germany.......... 729 Gold.Deposits,...........731 Bannack Type.........732 Elkhorn..........733 Similkameen.........734 Changes in Rocks due to Contact Metamorphism....735 Changes in Mass. Volume. and Mineral Composition... 736 Genesis of Contact Metamorphic Deposits..738 Cause of Contact Metamorphism..738 Permanence in Depth............744 Mineral Veins near Igneous Contacts........745 Conclusions..............746 Introduction. This paper deals with certain ore-deposits whose structural features or mineral contents (or both) result. directly or indirectly. from igneous intrusions and their afier-effects. It is largely a discussion of contact metamorphic ore-deposits based upon the physical changes in rocks due to contact action. It involves a classification of ore-deposits only so far as is abso-

Jan 1, 1903

By R. W. Raymond

THE absence of a convenient glossary of terms connected with mining and metallurgy has long been felt by the general public. It is to meet this want, not to furnish a technical manual for experts, that the following glossary has been prepared. It originated in an attempt on my part to revise for publication the manuscript of a compilation prepared from the appendix of Yale&apos;s work on Mining Titles and one or two other sources, to serve as an appendix to a new work on mining law, about to be published by Mr. H. N. Copp, of Washington, D. C. This revision soon assumed, contrary to my original intention, the proportions of a reconstruction; and with the consent of Mr. Copp, and for the purpose of receiving from my fellow-members valuable aid, I presented my still incomplete work as a paper at the Lake Superior meeting of the Institute, inviting from any quarter suggestions of new terms or better definitions to be incorporated in the glossary before its final publication. This invitation was so widely and generously responded to, that I cannot undertake to make in this place individual acknowledgments to those members of the Institute, and professional colleagues outside of it, who have favored me with assistance and advice. The labor bestowed upon this paper since its presentation at the Lake Superior meeting has considerably exceeded that of its first preparation, as may be inferred from its great increase in length, as well as the numerous alterations which it has undergone. It could certainly be still further enlarged and improved; but I think a comparison of it with any of the glossaries of the same class now in print will show, at least, that it is an advance upon what has hitherto been accomplished. 1 shall be grateful, however, for further criticisms and suggestions; and I purpose at some future time to incorporate in a supplementary paper the results of such additional collections or corrections as I may obtain. To avoid too great prolixity, I adopted at the outset the following general principles: 1. To include the most important technical words and phrases used by American miners and metallurgists, or occurring in English books and periodicals.

Jan 1, 1881

By T. R. Graham, J. R. Long

This report is concerned with part of a series of investigations carried on by the Federal Bureau of Mines on alloys, particularly nonferrous alloys, made with electrolytic manganese. A broad general program instituted after commercial quantities of electrolytic manganese became available was necessary in order to compare the effects of electrolytic manganese with those of the ordinary commercial grades. Representative analyses of these two materials show the commercial manganese metal to contain up to 2 per cent iron, a maximum of I per cent silicon and 0.06 per cent carbon, while the electrolytic manganese rarely exceeds 0.01 iron, 0.02 sulphur, with no silicon or aluminum. In the literature, the emphasis has been largely on high-strength casting alloys containing up to 5 per cent manganese, and few data are available on wrought manganese alloys. These factors, coupled with the strategic position of copper and zinc, have given impetus to the Bureau&apos;s War Research Program for the development of alloys containing nonstrategic manganese for the purpose of supplementing or providing alternates for the more strategic metals. The alloy reported here was studied, along with several other ferrous and nonferrous alloys, as possible cartridge-case material, and was chosen after a review of the properties of the ternary alloys of copper-manganese-zinc. Preliminary Work In a cursory survey of this system, alloys ranging from 60 to 95 per cent copper, o to 50 per cent manganese, and 5 to 40 per cent zinc were investigated. The alloys containing 60 per cent copper were found to fall into the two-phase alpha plus beta region of the system, and since those containing 70 per cent would not permit a saving, only alloys containing 65 per cent copper were considered. The tensile properties of these 65 per cent alloys are plotted in Fig. I as a function of manganese content for annealed material and for four conditions of cold-work In the annealed condition the increases in strength and decreases in elongation are minor up to 15 per cent manganese; beyond this, the changes become more significant. In the cold-worked condition, the first 5 to 10 per cent of manganese appears to have the greatest strengthening effect, the rate of increase dropping off as the manganese increases beyond this amount. These effects are more pronounced with moderate than with severe cold reduction. It is also interesting to note that while the elongation of annealed material drops regularly with increasing manganese, the elongation in the cold-worked state is relatively little affected by increasing manganese content, particu-

Jan 1, 1944

By J. R. Long, T. R. Graham

This report is concerned with part of a series of investigations carried on by the Federal Bureau of Mines on alloys, particularly nonferrous alloys, made with electrolytic manganese. A broad general program instituted after commercial quantities of electrolytic manganese became available was necessary in order to compare the effects of electrolytic manganese with those of the ordinary commercial grades. Representative analyses of these two materials show the commercial manganese metal to contain up to 2 per cent iron, a maximum of I per cent silicon and 0.06 per cent carbon, while the electrolytic manganese rarely exceeds 0.01 iron, 0.02 sulphur, with no silicon or aluminum. In the literature, the emphasis has been largely on high-strength casting alloys containing up to 5 per cent manganese, and few data are available on wrought manganese alloys. These factors, coupled with the strategic position of copper and zinc, have given impetus to the Bureau&apos;s War Research Program for the development of alloys containing nonstrategic manganese for the purpose of supplementing or providing alternates for the more strategic metals. The alloy reported here was studied, along with several other ferrous and nonferrous alloys, as possible cartridge-case material, and was chosen after a review of the properties of the ternary alloys of copper-manganese-zinc. Preliminary Work In a cursory survey of this system, alloys ranging from 60 to 95 per cent copper, o to 50 per cent manganese, and 5 to 40 per cent zinc were investigated. The alloys containing 60 per cent copper were found to fall into the two-phase alpha plus beta region of the system, and since those containing 70 per cent would not permit a saving, only alloys containing 65 per cent copper were considered. The tensile properties of these 65 per cent alloys are plotted in Fig. I as a function of manganese content for annealed material and for four conditions of cold-work In the annealed condition the increases in strength and decreases in elongation are minor up to 15 per cent manganese; beyond this, the changes become more significant. In the cold-worked condition, the first 5 to 10 per cent of manganese appears to have the greatest strengthening effect, the rate of increase dropping off as the manganese increases beyond this amount. These effects are more pronounced with moderate than with severe cold reduction. It is also interesting to note that while the elongation of annealed material drops regularly with increasing manganese, the elongation in the cold-worked state is relatively little affected by increasing manganese content, particu-

Jan 1, 1944

By William Romanoff

As you are no doubt aware, virgin copper, tin and zinc are strategic metals today and little, if any, is available in the manufacture of brass and bronze ingots. The source of alloys used in the manufacture of implements of war are, therefore, from ingots made almost exclusively from the refining of available scrap. It is amusing to hear of the unusual physical properties of various alloys because they mean nothing unless the foundryman is able to produce good sound castings. A discussion therefore means little unless something is said about the relative foundry practice of the various brass and bronze alloys. Among the factors that influence the quality of castings produced are: (I) improper gating, (2) wrong pouring temperatures, (3) poor sand conditions, (4) bad melting practice, (5) faulty pattern equipment, (6) metal. It seems to be the consensus of opinion that about 95 per cent of defective castings can be attributed to the first three causes. Metal while a source of trouble at times, is probably the least responsible for foundry difficulties. As you all know, a molder never makes a bad mold. His first thought is to blame the "damn" metal as this is the path of least resistance. Let&apos;s consider the "damn" metal and how it is made. In the manufacture of ingot, scrap is collected at various sources and is shipped to the refiner either directly or through the scrap dealer or broker. It is usually sorted, although not always. In working toward a specified chemical analysis, weighed amounts of various grades of scrap metals are melted, and then oxidized by blowing air through the molten bath to rid the metal of detrimental impurities or reduce them to within specification limits after which they are skimmed off with the aid of some added fluxes. The bath of metal is then poled with wood, chemically tested before and after additions are made to bring it up to required specifications, and finally poured into ingots, after which a final chemical and physical examination is made. As mentioned above, the impurities have either been eliminated or reduced to the point where they meet the specifications of all Government Agencies or Technical Societies. Therefore, why worry as to whether castings are to be made from strategic virgin metals or secondary ingots from available scrap. Tests have continuously been made and it is a proven fact that physical properties are no better from virgin metals than from secondary ingots of the same composition. It is definitely more fool-proof to make castings from secondary ingot than from virgin metals because if an error is made in weighing the copper, tin, lead or zinc of the latter, the analysis is off balance. If an error is made in weighing secondary ingots, you merely have more or less metal but the analysis remains constant. Furthermore, when pure copper is melted. it is susceptible to reducing gases as well as oxides. Secondary ingot is already alloyed with natural deoxidizers such as zinc, etc., and the volatilization of the latter also tends to eliminate reducing gases mechanically.

Jan 1, 1943

By Geoffrey Gilbert

The material that forms the basis of this paper was collected in the spring of 1922, during a ten-day visit to Ducktown by the writer in the company of Prof. L. C. Graton. The time available for the work was far too short to allow anything like a thorough study of the deposits, and structural and stratigraphic questions, though they have an important bearing on the origin of the primary ores, were necessarily left untouched. Attention was focussed on the zone of oxidation and enrichment; and by devoting most of our time to the upper levels, open pits, and old workings, and examining the deeper levels only thoroughly enough to obtain a fair idea of the nature of the primary sulfide ore, we were able to make a reasonably complete survey of the various orebodies. With this field work for a background, the writer later made a study, in the Harvard laboratories, of the specimens obtained during the visit. As some of the facts brought to light by this study appear to be new, it seems worth while to set forth the outstanding features and a proposed explanation of them. Much of the Ducktown material that is obviously of greatest significance, as regards oxidation and enrichment, is soft and crumbly. Notwithstanding the desirability of gaining from such material all possible information as to its mineral composition and textural relationships, but little has heretofore been learned regarding it; but, by suitable preparation of this material in connection with the present study, it has been possible to examine it under the microscope without any disturbance of its texture and about as satisfactorily as if it were hard, fresh ore. The information thus gained has contributed measurably to the results set forth in this paper.

Jan 1, 1924

By William Garrett

I have heard it said that the late Mr. Holley made use of this remark: " There is an inherent, cussedness about rolls which, so far, no man has been able to find out." I think this can be safely claimed in reference to steel, as there are certain peculiarities about it that are pretty hard to account for. Previous to the introduction of the Bessemer process there was, as it were, a great chasm between iron and crucible steel; and, outside of what futile attempts had been made in puddling steel, nothing had been done to fill this gap. The Bessemer steel struck a medium between the two, the softest of it not being able to take the place of good iron, while the hardest was not suitable to encroach very far upon the crucible-steel trade. The open-hearth process made quite an inroad into the latter, but only for the lower and cheaper grades; and, beyond a doubt, for the finest grades of tool-steel, the cruciblesteel business has a long life before it. On the other side of the line comes the " basic " process, which brings us a step nearer iron ; but to fill up the gap completely, comes the Clapp-Griffiths process, which makes a grade of material—call it what you will—that is as soft as iron, welds as readily, and is in a fair way to supersede iron altogether. For fifteen years, I was in the employment of the Cleveland

Jan 1, 1886

By James E. Jopling

The county of Marquette, Michigan, includes nearly all the iron-mines that have been worked on the Marquette range, which stretches in a generally western direction from the mines at Negaunee, 10 miles from Lake Superior, to those beyond Michigamme, some thirty miles further. The geographical position of this range, nearer to eastern ports than the other iron-ranges, and its ready access from the lake, gave it for a long time a controlling advantage. The country in which the mines are situated is from 800 to 1000 feet above the level of the lake, and is for the most part broken by steep hills, which rise from 100 to 200 feet; between these the land is rolling or

Jan 1, 1898

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&apos;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&apos;s a focal point for all types of minerals activities. It&apos;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&apos;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 Carl E. Swartz

Although a number of articles appeared during the war advocating the use of cadmium in lead-tin solders, very little information of value can be found in the literature regarding the properties of solders containing cadmium. In most of the published articles the cadmium seems to have been considered merely as a partial substitute for tin in a tin-lead alloy rather than as an essential constituent of a ternary alloy. The primary object of the substitution of cadmium for tin was to lessen the amount of tin required, at a time when the latter was scarce and high-priced, and thus to produce a cheaper solder. While this object was accomplished, the new properties resulting from a change from a binary lead-tin alloy to a ternary lead-tin-cadmium alloy were not given proper consideration in many cases. For the past few years, the American Smelting & Refining Co. has been marketing a very considerable amount of cadmium in the form of lead-tin-cadmium alloys for use as solders for certain special purposes, and the successful use of these solders suggested that if more extensive knowledge were available concerning the properties of lead-tin-cadmium alloys of various compositions their field of usefulness might be materially extended. The investigation described in the present paper was undertaken to obtain this information and, by means of tests under conditions approaching those of practical use, to determine the suitability of cadmium solders for various purposes. Characteristics and Requirements of Solders in General General Physical Properties.—When cast into bars, solder should present a smooth and bright appearance free from oxide inclusions and bubbles. Ductility should be as great as possible without sacrificing tensile strength, and vice versa. Hardness and specific gravity are not of any great importance. Melting Characteristics.—The melting or solidification range is important. This statement applies both to the extent of the range and to the actual temperature at which complete solidification occurs. A rather narrow solidification range is desirable in soft solders in order that solidification may take place quickly. The solder should have high fluidity at temperatures only slightly above its melting range. For a

By G. W. Healy

G. W. Healy (union Carbide Metals 0.)-The author&apos;s paper is a useful contribution to the store of maps of chemical activities of oxides in multi-component slag systems. It is also a good example of the utility of the Gibbs-Schuhmann technique for calculating activities in a system where that of one of the components has been measured. This paper Koh and Caugherty. This plot is reproduced by alor in X-ray Metallography. Because of this nonlinearity, preparation cf suitable standards and/or correction for absorption and enhancement are essential in microanalysis. However, our objection is not the conclusion that Dr. Aaronson has arrived at nor the technique he has used; but only to the foot-note credited to V. Macres. The level of chromium that he was concerned with (less than 3 pet) is so low that the deviation of uncorrected Cr-curve will be negligible. Besides Dr. Aaronson has used chromium intensity from martensite and set it equal the bulk chromium content of the alloy. Using this chromium-intensity as a reference, he has calculated the amount of chromium in the ferrite. This amounts to the same as using an internal standard. Since the chromium content in austenite and ferrite are almost the same, enhancement due to iron in both will be the same and therefore does not need to be corrected. together with the author&apos;s recently published one1 on the CaO-FeO-Fe2O3 system will be most helpful to others learning to apply Schuhmann&apos;s method, which merits a far wider application than it has received to date and should greatly aid our understanding of equilibria between metal and oxide phases. As shown by okcen" its use may even be extended to sections of systems with any number of oxides. I have some questions as to the selection of equilibrium constants made by Dr. Turkdogan. He has chosen one for the formation of Fez03 from FeO and oxygen which gives Fea3 activities 50 pct higher

Jan 1, 1963

By John D. Gill

The purpose of this paper is to invite attention away from the obvious. direct monetary costs of oil-field overdevelopment (as distinguished from "social costs") to a consideration of the role played by the exercise of freedom to create even allegedly excessive1 plant facilities in contributing to the maintenance of equilibrium in the wholc economy and in promoting material progress. The obvious and most commonly discussed effect of overdevelopment of oil fields is illustrated by the allegation that already the excessive development of the East Texas field has cost upward of $162,000,000;2 in other words, the drilling of 12,500 wells more than the number estimated as the requirement for economical recovery of the reserve has unnecessarily raised the total cost of development that amount. Many other illustrations of so-called excessive development of oil pools could be presented. Some of them, like Cushing, Powell and Long Beach, might be drawn from the era antedating widespread discussion in the trade of such matters as optimum well spacing, reservoir energy, the conservation rate of depletion of reserves, etc. Numerous other cases can he found in the records of the current era, which began with the introduction of rationalized restriction of production. Besides East Texas, there may be mentioned Oklahoma City, Centralia and. more recently, the town-lot development of Bloomingdale, Michigan.

Jan 1, 1940

By John D. Gill

The purpose of this paper is to invite attention away from the obvious. direct monetary costs of oil-field overdevelopment (as distinguished from "social costs") to a consideration of the role played by the exercise of freedom to create even allegedly excessive1 plant facilities in contributing to the maintenance of equilibrium in the wholc economy and in promoting material progress. The obvious and most commonly discussed effect of overdevelopment of oil fields is illustrated by the allegation that already the excessive development of the East Texas field has cost upward of $162,000,000;2 in other words, the drilling of 12,500 wells more than the number estimated as the requirement for economical recovery of the reserve has unnecessarily raised the total cost of development that amount. Many other illustrations of so-called excessive development of oil pools could be presented. Some of them, like Cushing, Powell and Long Beach, might be drawn from the era antedating widespread discussion in the trade of such matters as optimum well spacing, reservoir energy, the conservation rate of depletion of reserves, etc. Numerous other cases can he found in the records of the current era, which began with the introduction of rationalized restriction of production. Besides East Texas, there may be mentioned Oklahoma City, Centralia and. more recently, the town-lot development of Bloomingdale, Michigan.

Jan 1, 1940

By Edward A. Vitunac

The emerging importance of pneumatic conveying systems for bulk materials is largely due to the economic advantages such systems frequently exhibit when compared to alternate methods. Included in these advantages are relative simplicity, ease of installation, flexibility, ease of maintenance, cleanliness, safety and ease of automation to the degree desired. In general, installed costs favor a pneumatic system when compared to competing mechanical systems if the transporting distances are long or to and from many points. In addition, supplemental use such as cooling, heating, or drying may supply the incremental value required to justify its selection.1 The main disadvantages of a pneumatic system are the greater horsepower required per unit weight of material conveyed, material limits in abrasiveness, and density. In addition, material breakage tends to increase at changes of direction and at any obstruction such as that caused by the imperfect butting of two pipe sections in the conveying line. Classification of the material at the discharge may also cause problems in dusting and segregation. Materials weighing less than 4 lb per cu ft tend to cause feeding and collecting problems although they can be conveyed easily. Material between 4 lb and 20 lb per cu ft can be handled with fewer problems, but flow rate is hard to predict. The 20-60 lb per cu ft range offers best results, whereas materials of over 60 Ib per cu ft tend to drop out of the air stream and settle in the pipeline unless careful pro- visions are made to prevent this.2

Jan 5, 1968

By Wolfgang Hermann

The ancit-process of the Eschweiler Bergwerks-Verein, an affiliate Company of ARBED S.A., Luxembourg, was developed in its principles by the Dutch State Mines, Limburg, in the mid-50&apos;s with the aim of producing a smokeless domestic fuel on the basis of low volatile hard coal. In 1967, the EBV erected a 10 t/h large- size pilot plant along these principles in the Aachen mining district and further developed the acquired know-how. In hardly 10 years more than 650 000 t of ancit briquettes with unit weights between 17 and 100 grams were produced and in the meantime stream rates of over 85 % of the yearly utilization hours have been reached. In more than 10 blast furnace trial runs involving substitution rates up to 100 p. c. ancit have proved the suitability of ancit as a metallurgical fuel both for a burden with a high and a poor iron content. Construction work for a minor process-step to enable processing of coal with a higher content of volatile matters is finished and first results are expected by summer this year. A pilot plant with a 30 t/h capacity working on a low-volatile coal basis is being planned. Engineering and construction are supervised by MecanARBED. Luxembourg, as responsible contractors.

Jan 1, 1977

By V. E. Elliott, C. L. Meyette

THE conditioning of semifinished steel products such as billets, blooms, and slabs to remove surface defects before further processing to finished products is a necessary accompaniment to steel mill rolling operations. A knowledge of the kinds of defects which occur and of the conditions in melting, teeming, and rolling that may lead to their occurrence is favorable to the production of quality products. Surface defects may be classed as either of mechanical origin such as those that occur in the heating and rolling operations and include breaks, tears, guide marks, mechanical laps and the like, or they may have been in the ingot before heating and rolling. Examples of the latter are ingot cracks, blow-holes, scabs, and inclusions which lead to the numerous known types of seams -and surface flaws. Most of the common types of surface defects and methods for their identification by visual examination or by the aid of macro-etch tests are well known. The conditions which caused their formation are also appreciably understood and this knowledge has been instrumental in the establishment of methods for metallurgical control. There are, however, defects of doubtful origin. In any endeavor to trace the causes for their occurrence, the question of first concern is: I. Whether they were formed in the rolling procedure. 2. Whether they existed in the ingot prior to rolling. In the case of semifinished products which are rerolled to finished products there is also the question of whether they were formed in the primary or in the secondary rolling. In metallurgical laboratories where numerous or routine examinations of the quality of rolled products are made over the course of time, there will doubtless be many puzzling cases of defect origin. Microscopic examination of the defects may, however, reveal a characterizing condition that can be used to classify them broadly with respect to their origin. Such a condition has been observed and, after detailed investigation, is described here with the thought that it may offer a useable and relatively simple solution to a bothersome problem. BASIS FOR CLASSIFYING In this discussion the term "mechanical type defects" will be used to designate those that have occurred as a result of the rolling operations such as in rolling from the ingot to billets, blooms, or slabs or in rerolling to finished products. The term "steel type defects" will he used to designate those that were present in the ingot prior to primary rolling or that were in the semifinished product prior to secondary rolling to finished product. The basis for distinguishing between the two types of defects lies in the relative degree of subscale formation surrounding them. Subscale is defined&apos; as a zone of

Jan 1, 1948

By George F. Becker

Complexity of Rock-Fractures. - The strains to which rocks have been subjected are manifestly very complex, and it is entirely safe to presume that every possible node of deformation and rupture is exemplified. The most superficial inspection of any ordinary mountain region is sufficient to assure the observer that the rocks have been pressed, stretched, bent, buckled, twisted, and shorn. The study of torsional rupture cannot fail, therefore, to throw light on geological phenomena. The question is, how areas which have been broken in this manner are to be distinguished from those which have yielded to other systems of forces. Phenomena of Joints. - It is well known that a large part of the more homogeneous rocks and some very heterogeneous rocks are intersected by partings, often called joints. These partings are frequently flat surfaces, even when seen in very large exposures, but are sometimes surfaces of moderate single or double curvature. Joints usually occur in groups, in each of which the several partings are parallel to one another, and several such groups often intersect the same rock-mass. In such cases the different systems make large angles with one another. Nearly all students of the subject of jointing have reached the conclusion that joints are faulted surfaces, the dislocations usually being of small amplitude; and this conclusion receives abundant support from the study of thin sections under the microscope. It has thus been shown that much even of what would be regarded in I hand-specimens as mere slaty cleavage consists, in reality, of innumerable microscopic faults. For this reason, Mr. Daubrée rejects the term "joint," as failing to imply the existence of relative motion, and has introduced the terms “diaclase” and “paraclase” as substitutes.1

Jan 1, 1913

By Evan Just

THE high standards of living and improved national security that industrialization can bring are so evident that no country can be named that does not cherish the hope of industrializing. With such a universal aim, why do many countries unable to develop their own industries accomplish so little toward attracting the foreign private investor, who alone can provide them with the necessary capital and skill? Obviously, because they fail to under- stand what constitutes a favorable climate for investment, because they have false notions about being exploited or dominated by the foreign investor, or because they are so nationalistic they refuse to permit outside assistance. The purpose of this paper is to aid the citizens and policy makers of developing countries in achieving their aims, by defining the conditions which en- courage investment and portraying the results of a policy of encouragement. The following is quoted from Eugene R. Black, president of the World Bank:

Jan 6, 1957

The Manufacturer&apos;s Viewpoint A prominent manufacturer of mining &apos;machinery not long ago expressed himself as being confident that he was securing the best kind of publicity for his product through the advertising pages of the monthly Bulletin of the American Institute of Mining Engineers. Such an expression coming from such a man is highly gratifying; yet it is justifiable when the high quality of reader and subscriber is taken into consideration. In fact, the majority of those using our advertising pages feel the same. It is to be regretted, of course, that others catering to our field do not realize the means at their disposal for presenting the points of interest of their product to the mining man. The question has been asked, " Do your members read their Bulletin?" They not only read the editorial pages, but they "admit being up-to-date enough to peruse the advertising section to "see what is new." The next question the prospective advertiser asks is, " Will the Bulletin bring inquiries?" The answer to this question holds good for any publication having as subscribers those who have purchasing or recommending power-yes, if the article advertised is not a stock one, that has been before the public for any length of time. To secure inquiries on, say, a standard centrifugal pump or any other standard product, the features of which are well known, is a most difficult proposition. Yet, of course, some inquiries are secured, but mostly from those having use for the catalogue or trade literature for reference purposes. It is safe to say that the traceable returns from advertising in trade publications hardly, if at all, pay for the advertising. The real returns are intangible, and result from the constant publicity, and keeping ?everlastingly at it." Who can say what subconscious effect is taking place when an advertisement is "glanced at," to say nothing of the effect produced when the copy is attractive and interests the reader. Time after time it has been proved that sales have been secured as a result of an advertisement, yet no inquiry had been made directly traceable to advertising.

Jan 8, 1915