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By C. H. Loux

This paper deals primarily with the advantages realized from the adoption of methods more suitable than those previously used. The improvements noted include: (1) modification of practice in shrinkage stoping, (2) use of sublevel caving over grizzlies, (3) improved haulage and loading, (4) use of contract wages wherever possible. The Washington mine is on Jonestown Hill, one mile south of Oxford, in northwestern New Jersey. It is producing 16,000 tons of concentrates a month, which are being shipped to the Alan Wood Steel Company's furnaces at Swedeland, Pennsylvania. History The first settlement in this region is reported to have been in 1735, and the magnetite ores were recognized immediately. The first furnace, built in 1741, began operation in 1743. During the Revolutionary War the output was chiefly used for making cannon balls, which, owing to the sympathies of the community, without doubt found their way into the hands of the British. This old furnace is still standing. Several important veins were soon developed, including the Martin, Strayley, McKinley, Adelaide, Welsh and Lanning. Mining was carried to a depth corresponding to the capacity of the pumps available. When these became inadequate, the workings were abandoned, and another vein was opened up. The Washington vein was probably discovered about 1850, and the first shaft started in 1854. In 1879, William H. Scranton made the first complete magnetic survey of the district and serious exploration of the deposit was begun. Rather indifferent success attended the earlier efforts of the many companies that attempted to mine and smelt the ore. In 1929 the property was leased by the Warren Foundry and Pipe Co. to the present operators, and the modification of practice then inaugurated is described in this paper. Geology These veins, like most eastern deposits of magnetite, are formed from, or are contemporaneous with, pegmatite intrusions into a gneissic country rock. The ore therefore follows the banded structure of the gneiss,

Jan 1, 1934

By R. E. Ogilvie, E. T. Peters

The X-ray Kossel-line method has been used preaioz~sly for measuring lattice parameters to accuracies of 1 part in 100,000.5 A second application of this method is described for determining the crystallographic orientation of a randomly positioned single-crysta1 spherical volume that can he as small as 50 µ in diameter, within accuracy limits of ±1/2 deg. The theory, experimental procedure, and interpretation of Kossel-line patterns and an experimenta1 verification of the predicted orientation relationship of the cph k and fee a Cu-Si phases are presented. This orientation relationship can be described as (111)a, (00.1)k; [110]a [11.0]k. In addition, the lattice parameter of the a phase was found to he a. = 3.62154 ± 0.00014Å. The Kossel-line method when used in conjunction with electron microanalysis is shown to he capable of providing a complete chemical and structural analysis of a given crystal. THE most easily accomplished methods for determining the orientation of a single crystal are variations of the Laue X-ray diffraction method. Although certain materials can be oriented to within ± 1 deg accuracy by observation of exterior macroscopic features, such as etch pits, cleavage faces, or growth features, the Laue method is generally preferred for routine laboratory application. Both back-reflection and transmission patterns are coordinated by appropriate reference charts and are plotted in terms of reflection plane poles (normals) on a stereographic projection. Orientation is deduced by relating the pole distribution (which is fixed by the crystallographic symmetry of the specimen) to two specified external reference directions. The Laue method has several limitations. 1) Orientation can rarely be determined to better than ±l deg accuracy. Principal errors involve inaccuracy in specimen-to-film distance, measurement confidence of individual Laue spots, and stereographic plotting. 2) Because of the indeterminacy of the X-ray wave length diffracted to a given spot, it is not possible to determine supplementary crystallographic data, such as interplanar spacings and lattice parameters. 3) The method is generally limited to specimens of cubic symmetry or to specimens of high symmetry and known structure. 4) The relatively large cross-sectional area of the incident X-ray beam generally precludes the measurement of relative grain orientation in a polycrystalline material.* _____ Several of these limitations can be overcome by application of the Kossel-line method, which has been previously employed for precision lattice-parameter determinations.'-= For this method, a point source of divergent monochromatic X-rays is generated within the crystal by means of an incident electron beam. The divergent X-rays which fulfill the Bragg law are diffracted by the specimen and are recorded on a film placed either in transmission or back reflection. Analysis of the film yields a direct measurement of orientation and lattice-spacing values to an accuracy of ±1/2 pct. As analyses can be obtained from spherical specimen volumes as small as 50 µ in diameter, the method provides a means for structural analysis of second-phase or impurity precipitates within a given matrix. The primary limitation of the Kossel-line method is the requirement for an electron microanalyzer or similar apparatus capable of producing a finely focused electron beam. This paper is designed to present the theory, experimental procedure, and geometrical interpretation of Kossel patterns. The experimentally determined orientation relationship between the k and a phases occurring in the Cu-Si system and a precision measurement of the a lattice parameter are presented as a practical application of the method. THEORY OF KOSSEL LINES Divergent X-ray beam photography utilizes an effective point source of characteristic X-rays which, when diffracted from a single crystal, form numerous diffraction and absorption cones that are recorded on film.7 The cones generated from a source lying within the crystal are called Kossel lines.' Although the X-ray scattering from a divergent point source contained within a crystal is described in terms of Laue dynamical theory,9 the directions of the diffracted spectra can be ade-

Jan 1, 1965

By Granville S. Borden

MANY complaints have been filed by mine prospectors, explorers and producers about inequities in mining taxation. They have insisted upon improvement, and in the past 35 years there has been some progress. Many of the best taxation provisions made to date are those contained in the Revenue Act of 1951. Mining economics presents special problems, a fact even recognized by many textbooks. Certain provisions have been made to take care of mining taxation rights, but these have been made by Congressional act and do not represent basic, constitutional, guarantees. Despite special provision, in the form of depletion allowances, there remain injustices. The industry faces the problem of gaining adequate income tax allowances for exploration and development expenditures, operating losses, and bonus and subsidy payments. Problems in mine taxation arose soon after the adoption of the 16th Amendment. This amendment gave Congress the power to impose income taxes. Supreme Court decisions against a number of mining companies held that Congress, under its power to tax income, could tax net operating revenue before depletion allowance was deducted. The court also ruled that the right to deduct depletion is a matter of Congressional permission. There is no statute provision permitting mining stockholders to recover their investment out of dividends while the mine is being operated. The Supreme Court did not recognize that part of mining proceeds are actually amortization of the cost of mineral rights. Both these omissions stem from failure to recognize that by its very nature mining consumes its mineral rights and therefore that a part of gross proceeds are not income but recovery of capital. Suppose a Congress unfriendly to mining interests repeals the provisions that allow deductions for depletion. Under such a situation assume that a corporation buys a mineral deposit for $300,000. They mine the deposit and earn an operating profit of $500,000. At the current rates they would pay a Federal Income tax of in excess of $250,000. This venture results in a loss of $50,000 as shown in the table below. For the example given the absence of depletion provisions in income tax law would turn ore into waste rock, because the word "ore" connotes commercially mineable rock. [ ] In retrospect the conclusion is clear: If the Supreme Court had recognized that a part of mining proceeds represent in reality sales proceeds of mineral rights, then profits derived from such sales would have been taxed at the favorable long-term capital rates, instead of being taxed at the high normal, surtax and excess profits rates. It is a question whether percentage depletion allowances offset this tax situation. History The history of depletion allowances has been one of general improvement. The original act did not include depletion, but an allowance at the rate of 5 pct of gross proceeds was provided in 1913. The Acts of 1916 and 1917 allowed depletion upon cost of property, and in 1918 the law was further changed to permit depletion upon cost, or market value as of date of discovery. In 1932 metal, coal and sulphur properties were permitted to elect depletion in percentages of gross income, limited to 50 pct of net income, in lieu of cost depletion. Shortly thereafter the rule was changed and percentage depletion is now allowable in any case where it is higher than cost depletion. Since 1942 percentage depletion allowances have been extended to cover many nonmetals, and in 1951 the rate for coal mines was increased from 5 to 10 pct of gross income. It is interesting to note that these allowances have been retained, and even

Jan 1, 1952

By Maurice Ewing, J. A. Peoples, J. W. Peoples, A. P. Craby

The purpose of this paper is to present the results of the application of the earth-resistivity method of subsurface investigation to the problem of locating seams of anthracite coal beneath a mantle of soil and subsoil. Details are given of the successful use of this method in locating the outcrops of anthracite seams in actual prospecting. The presence of the outcrop of an anthracite seam is indicated at points where electrical resistivity tests showed relatively low readings. The reason for this is that in some localities the resistivity of anthracite was found to be about 0.0001 megohm-cm. compared to 1 to 200 megohm-cm. for shales and sandstones. For two reasons it is believed that the data summarized in this paper should be of particular interest. In the first place, most of the interpretations of the resistivity survey have been checked by subsequent drilling and some by the removal of the overburden and the exposing of the anthracite seams. It is infrequent that the opportunity for checking results so thoroughly is given. In the second place, the fact that recent commentatorsl,2,3 on the application of geophysical methods to mining have concluded that direct prospecting for anthracite and other types of coal is not promising makes the good results obtained more significant. So far as the authors can learn, the only previous experiment with electrical methods in the Pennsylvania anthracite field was one made by Sherwin F. Kelly in 1921, when he used the self-potential method at Wilkes-Barre4. The profile he made does not show a very marked correlation with the geologic cross section. Kelly points out that stray currents from electric motors in the mines undoubtedly affected 'his results, but the experience of the present authors with stray currents from mining machinery suggests the possibility that the potentials measured by Kelly were due almost entirely to this effect.

Jan 1, 1936

By Maurice Ewing, A. P. Craby, J. W. Peoples, J. A. Peoples

The purpose of this paper is to present the results of the application of the earth-resistivity method of subsurface investigation to the problem of locating seams of anthracite coal beneath a mantle of soil and subsoil. Details are given of the successful use of this method in locating the outcrops of anthracite seams in actual prospecting. The presence of the outcrop of an anthracite seam is indicated at points where electrical resistivity tests showed relatively low readings. The reason for this is that in some localities the resistivity of anthracite was found to be about 0.0001 megohm-cm. compared to 1 to 200 megohm-cm. for shales and sandstones. For two reasons it is believed that the data summarized in this paper should be of particular interest. In the first place, most of the interpretations of the resistivity survey have been checked by subsequent drilling and some by the removal of the overburden and the exposing of the anthracite seams. It is infrequent that the opportunity for checking results so thoroughly is given. In the second place, the fact that recent commentatorsl,2,3 on the application of geophysical methods to mining have concluded that direct prospecting for anthracite and other types of coal is not promising makes the good results obtained more significant. So far as the authors can learn, the only previous experiment with electrical methods in the Pennsylvania anthracite field was one made by Sherwin F. Kelly in 1921, when he used the self-potential method at Wilkes-Barre4. The profile he made does not show a very marked correlation with the geologic cross section. Kelly points out that stray currents from electric motors in the mines undoubtedly affected 'his results, but the experience of the present authors with stray currents from mining machinery suggests the possibility that the potentials measured by Kelly were due almost entirely to this effect.

Jan 1, 1936

By Maurice Ewing

THE purpose of this paper is to present the results of the application of the earth-resistivity method of subsurface investigation to the problem of locating seams of anthracite coal beneath a mantle of soil and subsoil. Details are given of the successful use of this method in locating the outcrops of anthracite seams in actual prospecting. The presence of the outcrop of an anthracite seam is indicated at points where electrical resistivity tests showed relatively low readings. The reason for this is that in some localities the resistivity of anthracite was found to be about 0.0001 megohm-cm. compared to 1 to 200 megohm-cm. for shales and sandstones. For two reasons it is believed that the data sum-marized in this paper should be of particular interest. In the first place, most of the interpretations of the resistivity survey have been checked by subsequent drilling and some by the removal of the overburden and the exposing of the anthracite seams. It is infrequent that the oppor-tunity for checking results so thoroughly is given. In the second place, the fact that recent commentators1,2,3 on the application of geophysical methods to mining have concluded that direct prospecting for anthracite and other types of coal is not promising makes the good results obtained more significant. So far as the authors can learn, the only previous experiment with electrical methods in the Pennsylvania anthracite field was one made by Sherwin F. Kelly in 1922, when he used the self-potential method at Wilkes-Barre4. The profile he made does not show a very marked correlation with the geologic cross section. Kelly points out that stray currents from electric motors in the mines undoubtedly affected his results, but the experience of the present authors with stray currents from mining machinery suggests the possibility that the potentials measured by Kelly were due almost entirely to this effect.

Jan 1, 1936

By L. A. Morley, W. T. Parry

Laboratory prepared clay-quartz sand samples and fault gouge from an open pit slope undergoing plane-type failure were tested in the laboratory to determine potential mining applications of electroosmotic stabilization and to provide a better understanding of electrochemical hardening. Experiments with very low current densities and free access of electrolytes to both anode and cathode showed an increase in cohesion. Cohesion in a fault gouge increased by 9.3 to 113%, depending on location with respect to the electrodes. For this, power consumption was equivalent to 0.727 watt-hr per cu ft (25.69 watt-hr per cu m). Regions of electrochemical hardening were determined by pH and the anolyte used. Electroosmotic stabilization appears as a reasonable solution to some types of mining problems.

Jan 1, 1975

By Maurice Ewing

THE purpose of this paper is to present the results of the application of the earth-resistivity method of subsurface investigation to the problem of locating seams of anthracite coal beneath a mantle of soil and subsoil. Details are given of the successful use of this method in locating the outcrops of anthracite seams in actual prospecting. The presence of the outcrop of an anthracite seam is indicated at points where electrical resistivity tests showed relatively low readings. The reason for, this is that in some localities the resistivity of anthracite was found to be about 0.0001 megohm-cm. compared to 1 to 200 megohm-cm. for shales and sandstones. For two reasons it is believed that the data sum-marized in this paper should be of particular interest. In the first place, most of the interpretations of the resistivity survey have been checked by subsequent drilling and some by the removal of the overburden and the exposing of the anthracite seams. It is infrequent that the oppor-tunity for checking results so thoroughly is given. In the second place, the fact that recent commentators 1.2.1 on the application of geophysical methods to mining have concluded that direct prospecting for anthracite and other types of coal is not promising makes the good results obtained more significant. So far as the authors can learn, the only previous experiment with electrical methods in the Pennsylvania anthracite field was one made by Sherwin F. Kelly in 1922, when he used the self-potential method at Wilkes-Barre4. The profile he made does not show a very marked correlation with the geologic cross section. Kelly points out that stray currents from electric motors in the mines undoubtedly affected his results, but the experience of the present authors with stray currents from mining machinery suggests the possibility that the potentials measured by Kelly were due almost entirely to this effect.

Jan 1, 1936

By C. F. Clausen

"Cement" means binding agent or glue. It is derived from the Latin word "Caementum," the name of a limestone, chips of which were used in mortar more than 2,000 years ago in Italy. During the middle ages "cement" or "cement" generally denoted mortar. Today it means any binding material. The Thomas Register lists nearly 200 classifications for "cement" including automobile cement, household cement, rubber cement, etc. The material most commonly associated with this word, however, is portland cement which, when mixed with water and allowed to hydrate, is a ceramic binding material used to cement aggregates (crushed stone, gravel and sand) together in "concrete," the most universally used building material of today. It is estimated that more tons of concrete are used annually than all other building materials put together including steel, lumber, gypsum, bricks, tiles, aluminum and glass. Its use in foundations, building construction, sanitary work, dams, railroads, and highways, makes it difficult to conceive of modem civilization without concrete. A survey made in October 1955 showed the following uses of portland cement: [Percent Highways20 Nonresidential buildings20 Residential buildings15 Military construction10 Sewer and water works8 Public utilities10 Other (conservation, farm, and maintenance and repair)17 100] As of today, the percentage for highways is probably even higher. Ceramic binding materials have unquestionably been used in construction work for thousands of years. The mortar between the blocks of the great pyramids was calcined gypsum (plaster of paris). The use of calcined and slaked limestone goes back earlier than the Roman Empire. Gypsum, however, is relatively soft, and common lime mortar is not "hydraulic," i.e., it does not harden under water. The Greeks and Romans discovered later that an addition of a finely divided active siliceous material (Santorin earth or Pozzolana) would react with slaked lime to form a stronger, and hydraulic, cement. The Appian Way in Italy, Colosseum, and the great Aqueducts built by the Romans were made with this type cement, and some of these structures are still in existence today. However, not until 1756 did some serious research result in the development of better cements. In that year the English engineer, John Smeaton produced a stronger cement by burning a limestone containing considerable proportions of clayey impurities. Other investigations and improvements were made by Bryan Higgins, Bergmann, Joseph Parker, L. J. Vicat, J. F. John, James Frost, and I. C. Johnson.2 Traditionally, but perhaps unfairly to others, the invention of the prototype of today's portland cement is credited to the English mason Joseph Aspdin who in 1824 obtained a patent and gave the product its name, because in color the mortar produced from it resembled a natural building stone obtained from the British Isle of Portland. The contributions of Johnson and Aspdin were primarily the important step of preparing a synthetic mixture of lime and clay without depending on raw materials found in nature which might contain such elements in desirable proportions. However, even these early

Jan 1, 1960

By Kenneth R. Hancock

Iron oxides are unique in that they are the only significant colored mineral found in a natural state suitable for use as a pigment after being pulverized to pigmentary size. The current world production of iron oxide pigments is estimated by the author to be between 499 and 590 kt (550,000 and 650,000 st) based on 1979 data. The fact that highly colored natural deposits of iron ore are found throughout the world accounts for its use in prehistoric man's artistic cave paintings. These early artists did not realize that they had established man's first paint test fence which now has some 20,000 years of exposure. In addition to abundance, constituting about 7 % of the earth's crust, iron oxides have the advantages of low cost, permanency, and are not toxic. Through the centuries, succeeding civilizations have utilized iron oxides as a major source for decoration and protection when coloring was desired. In the last century the chemical industry has improved on nature by developing a complete range of synthetic iron oxide pigments which surpass the pigments produced from natural iron ores in uniformity, color quality, and chemical purity. In the United States alone, the combined production of natural and synthetic iron oxides produced sales of over $28,000,000 in 1970 (Stipp, 1970) and increasing to $97 million by 1980 (Spinrad, 1980). Nomenclature With the increasing importance of the synthetic iron oxides it is necessary to make a distinction between the natural or mineral pigments and the synthetic pigments. Natural pigments are those products which are derived from selected ores and should not be confused with iron ores mined for steel production. Iron ores that are mined for steel must be capable of being mined and reduced to iron on a commercial basis. These ores are selected on the basis of iron content and processing economics. It is therefore unusual when iron ores for steel production are suitable for use as mineral pigments. Natural pigment ore sources are selected for their special physical-chemical properties and can command a premium price. Synthetic pigments, and in this instance iron oxides, are those pigments produced from basic chemicals. Through chemical synthesis pigmentary sized particles are produced as opposed to comminution, the major procedure common to all natural iron oxide pigments. Classification An important characteristic of a pigment is its color and, therefore, a logical separation can be made on this basis. A. Yellow Iron Oxide Pigments 1. Natural mineral origin a) Goethite b) Lepidocrocite c) Ochres d) Siennas e) Limonite 2. Synthetic pigments a) Goethite B. Red Iron Oxide Pigments 1. Natural mineral origin a) Hematite b) Siderite (calcined) c) Pyrites (calcined) 2. Synthetic pigments a) Hematite C. Brown Iron Oxide Pigments 1. Natural mineral origin a) Umbers b) Limonite (calcined) c) Siderite (calcined) d) Goethite (bog ore or sulfur mud) 2. Synthetic pigments a) Blends of hematite, goethite, and magnetite

Jan 1, 1983

By O. W. Walvoord

To those working in the mineral industry, the flowsheet is a familiar and valuable tool, seldom used, unfortunately, to its fullest advantage. As with so many other commonplace and simple items, there is little or no attempt to expand on the forms, and types of flowsheets. A flowsheet or flow diagram may be defined as an illustration showing circulation of the ore stream in a concentrating plant. It may be further described as an explanatory graphic design or picture. A flowsheet is obtained by interpreting the metallurgists' research and ore test data, usually with some adjustments to suit the economies of the project. It brings together, in compact form, information from a number of sources.

Oct 1, 1956

By Zay Jeffries

IN this paper, it is proposed to outline a method for the determination of melting points of those metals and alloys having high fusion temperatures. The application of the method as used to determine the melting points of alloys of tungsten and molybdenum will be given. It will be seen from these results that tungsten and molybdenum form a completely FIG. 1.-PARTIAL SECTION OF APPARATUS USED TO DETERMINE MELTING POINTS OF TUNGSTEN AND MOLYBDENUM ALLOYS. isomorphous series. This is also verified by the accompanying photomicrographs. Tungsten and molybdenum have been found to crystallize in the salve system, namely, isometric, and the crystal units are cubes. These determinations were made by examining etching pits in the pure metals.

Jan 7, 1916

By D. E. Swets, P. C. Frank, D. L. Fry

THE hydrogen-steel system has received considerable attention in the past several years. Recent experiments in this laboratory have shown that another group of operations, namely, sanding and grinding,' must be added to the already well-estab- lished list of phenomena that cause hydrogen to permeate steel. Qualitative tests which have been made with a very sensitive ion-gage type of detector similar to that used by Norton,' showed that sanding a steel surface caused hydrogen permeation. A metal type 6~6 vacuum tube was used as the ion gage with an electrometer to measure the ion c~rrent.~ The protective enamel coating was removed from the tube.

Jan 1, 1959

The Committee on Nominations will welcome from members of the Institute suggestions for the offices which are to be filled by election in February, 1018, and which are as follows: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and. VII of the Constitution, and to By-Law VIII, which reads as follows: "The geographical districts to he considered by the Committee on Nominations shall be as follows, until otherwise ordered by the Board.

Jan 8, 1917

By Gifford Pinchot

The proposition that forest reserves are, from the mining point of view, not only desirable but necessary, is not one which would have received enthusiastic support in. the West a year ago. It is, nevertheless, easily susceptible of proof. A short and simple statement of the facts has seldom failed to carry conviction as to the wisdom of the forest-reservation policy. Hostility to mining interests was never contemplated by the men to whom the forest reserves are chiefly due, and it is most unfortunate that the opposite belief should have obtained wide

Jan 1, 1899

V. H. GOTTSCHALK, Rolla, Mo. (written discussion*).-In connection with Mr. Waring's quotation of Urbain's work, attention may be drawn to a remark found in the report of the session of the Société de Chimie Physique,1 held in December, 1909, that, while all blendes contain gallium in larger or smaller quantities, those blendes carrying indium are generally free from germanium, and vice versa. Urbain, furthermore, . expresses his conviction that this behavior, being related to the condi-tions of deposition of the ore, should be an important factor in determining the origin and mode of formation of zinc blende deposits., In. searching the literature for the naturally expected sequel to these remarks, there is found a report on the extraction of germanium from blende, after many months' work, on a commercial scale;2 then a paper3 on some Spanish blendes, all containing cadmium, examined by Urbain's 'method (this paper contains, also, very important work on the com-position and color of blendes, as well as on the occurrence of organic .matter and of inclusions in such blendes), and a second paper on Spanish blendes in general, in which this original point of Urbain's concerning the relative quantities of the three rare elements is taken up.4 Angel del Campo finds that of 68 specimens examined, four only were entirely free of germanium, gallium, and indium;. 38 had small proportions, while 19 were notably, and seven relatively rich in the three rare metals. He found the relative frequency to be: gallium in 60, germanium in, 50, and indium in 38; all three occurred in 29 cases; germanium and gallium together in 18; gallium and indium together in four; germanium and indium together without gallium, in none; four had gallium only, three had germanium only, and one had indium only; in 23 it appeared feasible to extract these elements. Finally, it may be worth mentioning that the discovery of gallium in commercial aluminum5 brought forth two

Jan 1, 1918

By Fred D. Rosi

Introduction There is probably no field in which materials research has played a greater role than that of electronics. However, to trace present and future patterns of materials research in electronics is not an easy assignment, since this industry has a high degree of dynamism in its growth, and is busily engaged today in the scientific improbabilities of only recent yesterdays. On the other hand, this task seems especially appropriate since electronics is a truly frontier industry - one whose place in American industries has advanced from 50th prior to World War II to 6th in 1967, with sales of more than $22 billion. And this growth has been associated with the equally rapid progress of science and technology over the period - in particular with the emergence of materials science as a vital force in underscoring this progress. For several reasons this parallel growth is not too surprising. First, by its very definition electronics is a science that essentially deals with the nature, behavior, detection, generation, control and utilization of electrons in solids or at their surfaces. Second, in the electronics industry, systems are made of an integration of components, and these components with their interconnections are made of materials. Thus, the basic building blocks of systems are materials; and it has been largely the advances in materials research and technology that have led to new and improved devices and systems. It follows, therefore, that the broadening of the frontiers in electronics through the exploration of new territories is tantamount to scientific discovery and materials innovation to a degree found in no other major industrial activity. But to put this in the proper perspective of present and future materials trends, it would be appropriate first to survey historically the progress in electronics by pointing out major scientific discoveries and associated materials research patterns that have led directly to its tremendous growth. Then from this base we can consider recent trends in materials research that could form the basis for future progress in the electronics industry. In my review I shall examine the areas most familiar to me, so I must acknowledge at the outset that this survey is not all-inclusive.

Jan 1, 1971

By V. B. Kurfman

The temperature, strain rate, and orientation deDendence of defbrnzation of single-crystal MgAg has been examined. The crystals exhibit a tendency to single glide and little or no hardening at 25°C for many orientations. A much higher hardening rate is observed when multiple glide occurs, such as can be initiated by surface defects. The tendency for easy glide becomes less dependent on surface preparation and orientation as T — 100°C and bars so tested often fail after one-dimensional necking-. At T > 200°C (transition temperature for single-crystal notch sensitivity and poly crystalline ductility) single glide diminishes and two-dirnensionul necking begins. The crystals do not strictly obey a critical resolved shear stress law, but show the influence of {loo) cracks in determining the slip mode. The results are correlated with the difficulty of sciperdzslocation intersection and semibrittle behavior of this compound in single-crystal and poly crystalline form. Comparisons are made with the slip selection mode observed in tungsten, with the reported observations of easy glide in bee metals. and with the mechanical behavior of poly crystalline MgAg. PREVIOUS work on tensile deformation of polycrys-talline MgAgl and bending deformation of single-crystal MgAg2 has shown that the compound is semi-brittle (i.e., notch and grain boundary brittle). If this semibrittleness is supposed to result from the difficulty of multiple glide (associated with the problems of superdislocation intersection) one might expect single crystals deformed in tension to show pronounced single glide and strong orientation dependence of hardening rate. These experiments were done to examine this supposition and to study the tensile deformation of a highly ordered system which may be considered bcc if the difference between the two kinds of atoms is ignored (actual structure: CsC1). EXPERIMENTAL Single-crystal ingots were grown by directional freezing as previously described.' These ingots were sliced into a by a by 2 in, rectangular bars by electric discharge machining, then round tensile bars were conventionally machined to 1/8-in.-diam by 1-in.-long reduced section. The bars were typically tested without an anneal because of the problem of magnesium vapor loss and they were typically tested as mechanically polished. The analyses are within the same limits as those reported earlier; i.e., the average composition for each specimen is within 0.5 at. pct of stoichiometry, while the total range from end to end in a given specimen varies from 0.7 to 1.4 at, pct. There has been no indication in the results of any variation in slip or fracture mode attributable to the composition fluctuations. The slip systems were determined by two-surface analysis of the bars after testing to failure at room temperature. Single glide was so dominant that there was little difficulty in identification of the dominant slip system even though the tensile elongation to failure often approached 7 to 8 pct in room-tempera- ture tests. Elevated-temperature testing was done in a silicone oil bath and low-temperature testing was done in liquid Np or a dry-ice bath. All stress measurements are reported as engineering stress unless otherwise specified, and crosshead travel is used as the strain measurement. RESULTS The tendency toward single glide is best seen in the pictures, Figs. 1, 2, and 3, which depict deformation at fracture as a function of test temperature. While it is possible to find regions of secondary slip by careful microscopy, such regions are very small. The development of a ribbon-shaped configuration from an initially round section bar pulled at 100°C is typical, occurred by single glide, and illustrates the degree to which such glide continues. At temperatures =100°C the bars typically show elongation of 20 to 50 pct by predominently single glide. Despite the large elongation, fracture even at 150°C occurs in a brittle mode, Fig. 2, in the sense that it is an abrupt failure which shows no discernible necking in the second dimension of the bar's cross section (i.e., there is no appreciable action of any slip modes which would decrease the broad dimension of the cross section). Near 200°C the fracture mode changes slightly. Although most of the sample extension is by single glide, after the bar develops the characteristic ribbon shape it begins to neck in the second (i.e., broad) cross-sectional dimension. The bar becomes very thin in the "necked down" region, Fig. 3, and the reduction in area approaches 100 pct. Often there oc-

Jan 1, 1967

By Ernst A. Hauser

IN a paper published three years ago,' the term "silicic chemistry" was used for the first time to emphasize the increasing importance of the chemistry of silicon in science and technology. The development through which the colloid chemistry of siliceous matter has gone since then is in itself ample proof that the coining of this new term for this branch of colloid science was not presumptuous. Until quite recently, however, silicic chemistry concerned itself only with the composition and colloidal properties of natural and synthetic siliceous matter, but had not paid much attention to the genesis of this matter, particularly to that of the clay minerals. What is even more disturbing, particularly from an educational point of view, is the fact that neither mineralogy, geology, nor metallurgy has fully realized the important role colloidal phenomena must have played in the genesis of our planet and the formation of minerals generally speaking. Considering the importance of colloid chemistry today in the fields just mentioned, it is not surprising that the theories most agreed upon by geologists and mineralogists for the origin of clay minerals are not acceptable from a strictly colloid chemical point of view for the genesis of these most important and most abundant components of the earth. Of all the theories pertaining to the origin of clay minerals, those still most accepted by geologists and mineralogists are the "residual clay" and the "transported clay" theories.15 The former is based primarily on the assumption that the formation of clay minerals is the result of surface weathering of fresh rocks, or is due to the action of solutions. Taking the action of water on orthoclase as an example, the most recent ideas have been summarized by H. Jenny13 as follows:

Jan 1, 1952

By Frank Soulé

Secretary E. H. Benjamin, of the California Miners' Association, has proposed and begun, in co-operation with the testing laboratory of the University of California, at Berkeley, a series of tests which should prove of great interest and practical use to all persons making extensive application of steel wire cables, and especially to miners who run them in deep mines. Mr. Benjamin is endeavoring to obtain pieces of cable both new, and old and worn, from every deep mine of importance on the Pacific Coast, together with all the data obtainable concerning their manufacture and particular use. Pieces from each sample will be broken ill the laboratory before mentioned: and as far as possible the effects of winding around drums or pulleys ; of sudden starting and stopping when loaded; of heavy shocks, and of the general wear and tear of the cables, will be ascertained by these tests. The Olsen testing-machine of 200,000 pounds capacity will be used to break the cables, and the rupturing force, in different instances, will be applied slowly and also rapidly, in order to make the tests comparable as far as possible with the practical use of the cables themselves. All information and data available should be obtained for each specimen sent to the laboratory, the name of the manufacturer, the date of making, strength of cable when new and unrusted, as well as the circumstances and conditions of the practical use of the cable. Having this information before us, we shall be able to tell, approximately at least, the effects of age, rust, wear and tear, shocks, etc.; and perhaps be enabled to draw the line of limitation beyond which it would be no longer safe to use a cable of known manufacture. Moreover, by means of such tests we may, perhaps, he able to recommend worn cables for other uses, less severe in character, thereby prolonging the life of their effective usefulness. When we consider the great number of miles of steel cable now in use, and of the greater number constantly being manu-

Jan 1, 1900