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By Luther Lennox

DURING the last few years, one of the great problems in the milling of all ores has been that of crushing. This subject involves not merely the cost of the operation, but also the selection of the proper degree and character of crushing to yield the best metallurgical results on the given ore. Considering the diversity of machinery, one is led to wonder at the variety of crushing methods employed, even when realizing that metallurgy demands varying products. In an attempt to investigate the relative crushing resistances of a number of ores now being milled in this country and Alaska, the management of the Portland mills requested samples of average mill-run of ore from various companies. The request met with a ready response, indicating the desire of all operators to gain information on the subject. The difficulties involved in this investigation were numerous, lack of time for outside problems during this strenuous period being a serious one. Also, we were unable, in the time, to obtain a correct 150-mesh . screen; in the screen analyses tabulated and plotted herewith, the 150 mesh screen was used merely to protect the 200-mesh screen, not to ascertain points on the curves.

Jan 8, 1918

Member ship L P MATHEWSON, Chairman GEORGE D BARRON LOUIS D HUNTOON JOHN A CHURCH, JR H N SPICER Alternates LEWIS W FRANCIS WILBER JUDSON F T RUBIDGE Increase of Membership JOHN A CHURCH, JR, Chairman Other members to be appointed

Jan 1, 1923

MINING METHODS F A WARDLAW, JR, Chairman WILLIAM J COULTER, Past Chairman PHILIP B BUCKY, Past Chairman FRANCIS CAMERON, Vice-Chairman R D LONGYEAR, Vice-Chairman J MURRAY RIDDELL, Vice-Chairman LELAND A WALKER, Vice-Chairman E D GARDNER, Secretary

Jan 1, 1952

By T. A. Rickard

A knowledge of the principles of punctuation is essential to effective and intelligible writing, for the ease and pleasure of the reader, and even his understanding, may depend upon the choice and the placing of punctuation marks. To 'punctuate' is to mark with stops or points; the word comes from the medieval Latin punctuare (punctuatus), which in turn is derived from the Latin punctum, a point. The purpose of punctuation is to show the manner in which the writing is to be understood; to indicate the relations between parts of a sentence and between successive sentences. To some extent "it does for the eye what vocal stress does for the ear", but especially it marks logical relations. Some punctuation marks, such as those indicating admiration, exclamation, and interrogation, are rhetorical as well as grammatical, but most of the common ones are logical, or grammatical. My discussion will be confined to grammatical punctuation in ordinary writing. .'The problem of punctuation in text matter", as George Summey * says, "is to employ words, points, and paragraph breaks in such a way as to achieve at the same time clearness; proper distribution of emphasis, and the desired kind of movement." The criticism of the punctuation of a sentence or of a group of sentences is not final until the context, within the paragraph, is read. A paragraph is a sentence or a group of sentences forming an independent unit of the composition; it represents a unit of thought. A multiplicity of paragraphs produces a choppy effect; 'on the other hand, paragraphs of. excessive length are tiresome, because the belaboring of one unit of thought wearies the reader. The aim should be to

Jan 1, 1931

LIST OF MEMBERS AND ASSOCIATES ARRANGED ACCORDING TO STATES AND TOWNS. ALABAMA. Aldrich, Aldrich, W. F. Anniston, Noble, A. E Bessemer, Fergusson, V. Bir¬mingham, Aldrich, T. H., Jr, Bowron, C. E, Bowron, J., Davis, F H, Dimmick, F. D., Hillman, Ludwig, C. P., McCarthy, M. E, McCormack, G B., McCrery, Ramsay, E, Shook, A. M. Ensley, McDonald, S., Shook, J. W. Gadsden, Lee, R. H., Jr. Gannts Quarry, Hiller, E Helena, Squire, J. Huntsvalle, Moss Le¬high, Toulmin. Ozmoor, Greenamyer, A. G. Rock Run, Garvin, J M. Selma, Saylor, B. F. A. Sheffield, Miller, D, I. Tuscaloosa, Lodge, J. Woodward, Wood¬ward, A. H. ALASKA Coppermount, Wiswell, H. J. Douglas Island, Macdonald, J Ellamar, Stevens, B. Fairbanks, Hamilton, A L Haines, Le Wald, E A. Jualin, Hoggatt, W. B. Juneau, Denby, Hampton, W. H , Thane, B L , Whipple, J. R. Ketchikan, Bar¬ber, J C , Parker, J. L., Reid, G D Nome, Garfield, C D. Snettwham, Tisdale. Teller, Hirshberg, M. R. Treadwell Caty, Kinzie, Stow, H. P. Valdez, Esterly, G. M, Hazelet.

Jan 1, 1910

By H. R. Nelson, Martin S. Maier

The diffusion of metals plays an important role in many metallurgical processes,lJ as, for example, the formation of alloys by the annealing of mixed powders, the homogenization of segregated alloys, and the carburization of steel. Other equally important phenomena, such as recrystalli-zation and creep, are based on the movement of like atoms. Although much is known concerning the effects of diffusion in metals, very little is known concerning the details of the physical processes involved. 1,3-5 The data that should give most information concerning the processes involved in diffusion are those on the diffusion of like atoms—self-diffusion. Very little is known concerning the rates of self-diffusion of metals because before the discovery of artificial radioactivity in 1934 there was no means of detecting the movement of the diffusing atoms through the solvent metal except in the elements possessing natural radioactive isotopes—lead, thallium and bismuth. Using the induced radioactivity of the element as an indicator, atoms can now be "tagged" so that the rate of diffusion of the radioactive isotopes of an element (tagged atoms) into the stable isotopes of the same element can be measured. As the radioactive and stable isotopes of an element differ only in nuclear structure, it is quite certain that all isotopes of an element diffuse at the same rate. Two techniques have been used to measure self-diffusion. In one, a thin layer of radioactive metal is deposited on the face of the solvent metal, and the decrease in the surface activity as the radioactive atoms diffuse into the solvent metal is measured. This method has been used to determine the coefficients of self-diffusion of lead6-l0 and bismuth10 using natural radioactive isotopes, and of gold1' and copper12 using artificial radioactive isotopes. In the other technique a thin layer of the radioactive metal is deposited oil one face of the solvent metal, and after diffusion has occurred the specimen is cut in thin sections to obtain the concentration-penetration curve. This method has been used to determine the coefficients of self-diffusion of gold,13 zinc,14-l6 silver," and copper.17 The second method was used for the work described in this paper. Materials The coefficients of self-diffusion were determined in two grades of polycrystalline copper and in single crystals of copper. Commercial OFHC copper was used in the form of disks I in. in diameter by % in. thick. Samples of high-purity copper described by Phillips and Skinnerl9 were supplied through the courtesy of the American Smelting and Refining Co. The high-purity copper rod was used without remelting by cross-rolling to a thickness of 0.075 in., from which disks 7/8 in. in diameter were cut. A good grade of bus-bar copper was used to make the single crystals.

Jan 1, 1942

By Martin S. Maier, H. R. Nelson

The diffusion of metals plays an important role in many metallurgical processes,lJ as, for example, the formation of alloys by the annealing of mixed powders, the homogenization of segregated alloys, and the carburization of steel. Other equally important phenomena, such as recrystalli-zation and creep, are based on the movement of like atoms. Although much is known concerning the effects of diffusion in metals, very little is known concerning the details of the physical processes involved. 1,3-5 The data that should give most information concerning the processes involved in diffusion are those on the diffusion of like atoms—self-diffusion. Very little is known concerning the rates of self-diffusion of metals because before the discovery of artificial radioactivity in 1934 there was no means of detecting the movement of the diffusing atoms through the solvent metal except in the elements possessing natural radioactive isotopes—lead, thallium and bismuth. Using the induced radioactivity of the element as an indicator, atoms can now be "tagged" so that the rate of diffusion of the radioactive isotopes of an element (tagged atoms) into the stable isotopes of the same element can be measured. As the radioactive and stable isotopes of an element differ only in nuclear structure, it is quite certain that all isotopes of an element diffuse at the same rate. Two techniques have been used to measure self-diffusion. In one, a thin layer of radioactive metal is deposited on the face of the solvent metal, and the decrease in the surface activity as the radioactive atoms diffuse into the solvent metal is measured. This method has been used to determine the coefficients of self-diffusion of lead6-l0 and bismuth10 using natural radioactive isotopes, and of gold1' and copper12 using artificial radioactive isotopes. In the other technique a thin layer of the radioactive metal is deposited oil one face of the solvent metal, and after diffusion has occurred the specimen is cut in thin sections to obtain the concentration-penetration curve. This method has been used to determine the coefficients of self-diffusion of gold,13 zinc,14-l6 silver," and copper.17 The second method was used for the work described in this paper. Materials The coefficients of self-diffusion were determined in two grades of polycrystalline copper and in single crystals of copper. Commercial OFHC copper was used in the form of disks I in. in diameter by % in. thick. Samples of high-purity copper described by Phillips and Skinnerl9 were supplied through the courtesy of the American Smelting and Refining Co. The high-purity copper rod was used without remelting by cross-rolling to a thickness of 0.075 in., from which disks 7/8 in. in diameter were cut. A good grade of bus-bar copper was used to make the single crystals.

Jan 1, 1942

Executive SIDNEY J. JENNINGS, Chairman GEORGE D. BARRON J. E. JOHNSON, JR. EDWIN LUDLOW ROBERT M. RAYMOND Membership KARL EILERS, Chairman LEWIS W. FRANCIS J. E. JOHNSON, JR. LOUIS D. HUNTOON ARTHUR L. WALKER Finance GEORGE D. BARRON, Chairman CHARLES F. RAND BENJAMIN B. THAYER Library E. GYBBON SPILSBURY,1 Chairman ALEX C. HUMPHREYS2 GEORGE C. STONE2 J. H. JANEWAY4 BRADLEY STOUGHTON1

Jan 3, 1918

By Edgar L. Weinberg, W. Horatio Brown

The Austinville-Ivanhoe lead-zinc deposit occurs in the Lower Cambrian Shady dolomite. This deposit is located in southwestern Virginia in the faulted and folded Appalachian Valley and Ridge province. The ore bodies resemble the chimmey and manto deposits of northern Mexico and are formed by replacement and filling. They are confined to certain favorable zones of the Austinville and Ribbon members of the Shady. Structural and stratigraphic factors combine to control the location and form of the ore bodies. In certain places secondary oxide enrichment of the zinc minerals has contributed to the economic development of the area. It is concluded that the ore is epigenetic and is deposited by hydrothermal solutions rising through the fault "plumbing." Classification is epithermal-telethermal.

Jan 1, 1968

Executive SIDNEY .J. JENNINGS, Chairman GEORGE D. BAR HON .I. E. JOHNSON, JR. EDWIN LUDLOW ROBERT M. RAYMOND Membership KARL EILERS, chairman LEWIS W. FRANCIS .1. E. JOHNSON, JR. LOUIS D. HUNTOON ARTHUR. L. WALKER Finance GEORGE D. BARRON. Chairman. CHARLES F. RAND BENJAMIN B. THAYER Library E. GYBBON SPILSBURY1 Chairman ALEX C. HUMIPHREYS3 GEORGE C. STONE .J. H. JANEWAY4 BRADLEY STOUGHTON Papers and Publications BRADLEY STOUGHTON, Chairman

Jan 10, 1918

By B. G. Klugh

(New York Meeting, February, 1912). IN a paper before the Institute at Wilkes-Barre, Pa., June 1911,1 Mr. James Gayley discussed the application of this process to iron-bearing materials. The same author2 described the results of operations at the plant at Birdsboro, Pa. The purpose of the present paper is to present further discussion of some technical details involved in the operation of this plant, and of the theoretical and practical relations of this product to blast-furnace practice. Since Oct. 1, 1911, the Birdsboro plant has been in operation at the blast-furnace of the E. & G. Brooke Iron Co. The results have been highly satisfactory, although the material treated, being chiefly the flue-dust currently made by the furnace or taken from the accumulated stock-pile, was excessively high, and yet not uniform, in carbon, so that the desirable control or regularity of the amount of fuel in the mixture treated could not be maintained. Nothing could more forcibly demonstrate the flexibility of the process than the fact that, under these conditions, the sinter produced was, in all cases, of excellent quality. The Dwight & Lloyd process, as such, and its present highly-developed mechanical appliances were described by Mr. Gayley in the paper above mentioned. While the repetition of some particulars will be unavoidable in this paper, it will be confined to features bearing upon the metallurgical principles involved. According to the principle of the process, the finely-divided iron-bearing material to be sintered is intimately mixed with

May 1, 1912

By L. G. Margolin

INTRODUCTION In this paper we derive an expression to predict the onset of growth of a crack in a quasibrittle material. We employ an energy criterion, which was first proposed by Griffith (1920), and is essentially equivalent to the first two laws of thermodynamics. The criterion is applied to the elastic-plastic crack of Olesiak and Wnuk (1968), which is a three-dimensional generalization of the Dugdale (1960) crack. Our expression for the onset of growth differs in several respects from a criterion based on a crack in a brittle material (i.e., using linear elastic fracture mechanics) . Furthermore, the new features are in qualitative agreement with the experimental data. Among these new features are 1) the dependence of the apparent surface energy, or critical strain energy release rate on crack size (the shape of the R-curve); 2) the effect of in-plane stresses (i.e., the stresses that do not lead to any traction on the crack faces) on crack growth; and 3) a brittle-ductile transition. The energy criterion, as a necessary condition for crack growth, rests on a firm theoretical basis. However, its role as a sufficient condition is less secure. Several alternate criteria have been proposed as necessary and sufficient conditions for the onset of crack growth. We will contrast several of these, including critical strain (Olesiak and Wnuk, 1968; Goodier and Field, 1963) and crack opening displacement ("COD", Burdekin and Stone, 1966) with the energy criterion. We will show that these alternate approaches are inconsistent with the energy criterion, in the sense of being necessary conditions, and so should be rejected as criteria for growth--at least for the elastic-plastic crack.

Jan 1, 1984

By John F. Abel

"The most conservative persons I ever met are college undergraduates." Woodrow Wilson said that in 1905. No one is saying anything like it today. Chaos on the campus was a cliche of the sixties. Since 1905, education has expanded in every direction. Many more people are being educated for much longer periods of time. The school-leaving age has risen from 14 years to 20 years, on an average. Many are in school until after their 25th birthday. On the surface this situation appears all to the good. Our technical society needs a massive yearly infusion of semitrained (or educated, if you prefer) new blood. The efficiency of our economy and our standard of living are tied to high individual productivity which can be achieved only with an educated work force. Our democratic institutions are said to be founded on an educated electorate.

Jan 1, 1970

By E. J. Eisenach, Edward Matsen

AT the present time the Climax Molybdenum Co. is the largest molybdenum producer in the world and the operator of the largest underground mine in North America. It has grown steadily and rapidly since its beginning in 1917. Only 250,000 lb of MoS2 were produced during the first year from 1917 to 1918 when the company was formed. Operations were suspended shortly thereafter because of the lack of a market and knowledge of the uses of molybdenum. During World War I it was used as a substitute for some rare metals and for minor chemical purposes. After 5 years of intensive research and sales promotion, Climax metallurgists succeeded in finding proper applications for the newly discovered metal and the mine was reopened in 1924. Demand for molybdenum increased gradually and in 1930, 3.5 million lb of MoS2 were produced. In the meantime, research work for additional uses of molybdenum continued until it had established itself as one of the most important alloying elements in producing high quality steels. After the start of World War 11, from January 1942 to October 1953, 43 million tons of molybdenum ore were mined and 484 million lb of MoS2 were produced. Climax mine is located in Colorado, 100 miles southwest of Denver and 12 miles northeast of Leadville on the Continental Divide of the Rocky Mountains. The principal mine workings range from 11,170 to 12,000 ft in elevation. Topographically, it lies in the base of a large cirque that is surrounded by Mt. Bartlett to the north, Clinton Peak and McNamee Peak to the east and Ceresco Ridge to the south. This cirque opens to the west and to the Ten Mile Valley.

Jan 3, 1954

By T. B. Massalski, C. S. Barett

THAT metals and alloys of the body-centered-cubic structure tend to become unstable at low temperatures is so nearly universal that any exceptions are worthy of special attention. Studies of the exceptions may disclose unrecognized examples of metastability or may shed light on the nature of some of the factors that stabilize the body-centered-cubic phase. Among the structurally analogous body-centered-cubic 3/2 electron compounds, the ß-phase in the Cu-Zn system deserves further attention for, although this phase is known to undergo partial mar-tensitic transformation on cooling below room temperature to the temperature of liquid nitrogen when the composition is less than about 42 wt pct Zn, it does not transform on cooling .when there is more than this amount of zinc present.1-4 The present authors recently found that an alloy containing 48.35 wt pct Zn could be transformed, however, if deformed severely at room temperature or lower temperatures.V his discovery led to the suggestion that the jerky flow of ß-brass single crystals6 and some of the unusual temperature variations of the yield strength and hardness are due to strain-induced transformation during the tensile tests. The present investigation is an extension of that work to cover the entire available range of compositions of Cu-Zn ß-phase alloys and certain interesting compositions of the ß-phase in the Cu-Zn-Ga system. Particular attention is given to the structure of the transformation product resulting from cold work, which is found to vary with alloy composition, and to the temperature range in which transformation can be induced in the various alloys. The composition limits of the body-centered-cubic phase in the Cu-Zn system, based on a recent review by Raynor7 and the precision determinations of Beck and Smith: are shown in Fig. la; in the ß region the alloys are disordered and in the ß region they are ordered. The rate of ordering is so rapid that a high degree of order is found in any of these alloys immediately after quenching. Experimental The nine binary and four ternary alloys of this investigation were prepared from cathode copper (99.99 pct purity), electrolytic zinc (99.99+ pct), and gallium (99.98+ pct). All alloys were cast in transparent Vycor tubing, homogenized at temperatures between 800° and 890°C, and quenched in water. Ternary alloys were cast in small amounts (-5 g) to predetermined compositions to fall along a line of constant electron concentration in the ternary system. Changes of weight during the casting operation of the ternary alloys were not greater than 1 part in 2500 from the intended nominal weights and therefore their compositions were accepted without chemical analyses. All binary alloys were cast in larger amounts (100 to 150 g), homogenized, and hot rolled after preheating to 800°C. The central portion of the rolled strip of each alloy was annealed for eight days and quenched in brine. All binary alloys were analyzed chemically. The compositions, heat treatments, and metallographic appearances of all alloys are tabulated in Table I. Various samples were subjected to heat treatment or cold work at several temperatures and were then examined metallographically or by means of X-rays. Specimens about 6x6x3 mm in size were examined metallographic ally to confirm the presence of the ß-phase after quenching. Cold work was introduced by fastening each sample between two pieces of steel, cooling the assembly to the desired temperature, and transfering it rapidly to a vise where moderate or severe compression was immediately applied. Cold working at liquid helium temperature was done by a chisel-shaped tool mounted on an X-ray spectrometer, described elsewhere.% A!! metal-

Jan 1, 1958

EXECUTIVE COMMITTEE OF THE BOARD OF DIRECTORS EUGENE McAULIFFE, Chairman. L. E. YOUNG, Vice-chairman. CHESTER A. FULTON WIILBER JUDSOIN PAUL D. AMERICA FINANCE COMMITTEE OF THE BOARD OF DIRECTORS ERLE V. DAVELER, Chairman. HENRY KRUMB H. Y. WALKER ADMISSIONS FELIX E. WORMISER, Chairman GEORGE D. BARRON. Vice-Chairman CARROLL A. GARNER PHILIP KRAFT E. M. WISE

Jan 1, 1942

By H. M. Warren, E. J. Powell, A. S. Biesecker

In the past, steam engines were used in practically all cases for driving the machinery in and about an anthracite breaker, and hence few or no accurate data were available as to the power requirements for starting and operating the individual machines, which make up the complete equipment. It was impossible to segregate the power necessary to drive each individual machine, first, because the equipment was driven in groups, and second, because it was impracticable to obtain graphic, integrated, or instantaneous records of the horsepower used. As a result of these conditions, it was found, when individual electric motors were applied to the various machines, that more accurate and complete data were needed in order to provide motors of the proper power and design for the particular services to be rendered. In order to obtain the desired information, the writers made and collected a number of tests, from time to time, on the individual motor drives in electrically operated breakers, and as these tests have been of great value, it occurred to them that a paper giving the results might be of service to other engineers interested in similar installations. Table I shows the results of these tests. All the motors tested were of the three-phase, 60-cycle, 440-volt, induction, squirrel-cage type, except a few, which, on account of size and starting conditions, were of the wound-rotor type. The instruments used in making these tests were: An integrating watt-hour meter, a graphic ammeter, and a graphic voltmeter. These instruments were connected in each motor circuit, and a record of a day's run of 9 hours was obtained from each machine. From these tests, the running light load, the average all-day load, and the instantaneous peak readings in amperes, volts, and kilowatt input, were obtained. By means of the characteristic curves obtained from these motors at the factory, the power factor, the efficiency, and the horsepower output were calculated for each particular test. Starting tests were made by the brake-arm method, in which the torque in pounds was measured directly on a spring balance.

Jan 1, 1916

COMMITTEES Committee on Arrangements DAVID H. BROWNE, Chairman LAWRENCE ADDICKS THOMAS T. READ P. E. BARBOUR BURR A. ROBINSON GEORGE D. BARRON F. T. RUBIDGE KARL EILERS E. MALTBY SHIPP LOUIS D. HUNTOON BRADLEY STOUGHTON H.A. MEGRAW EDWARD B. STURGIS ARTHUR L. WALKER

Jan 4, 1917

By Hugh H. Waesche

High quality quartz crystals weighing more than 50 grams are required in several important industrial applications.30,31 Primarily, they are the basic raw material for precision, electronic, frequency control components; this includes oscillators and filters in both radio and telephone services. Quartz crystals are also necessary for optical lenses and prisms in special applications requiring high ultraviolet light-transmission as in spectrographs. Quartz wedges are regular components for petrographic microscopes. The application of crystalline quartz as a transducer* in ultrasonic devices has increased in recent years despite strong competition from barium titanate and magnetostrictive [f] devices. Some quartz is fabricated into delay lines for radar. Man has valued quartz for fabrication of art objects since the dawn of history. The art forms were and are painstakingly carved and polished to form intricate figurines, bowls, statuettes, and the well-known crystal balls. The largest known ball, made of perfect quartz from Burma, is now in the National Museum in Washington. It is 12 7/8 in. in diameter and weighs 106 lb 12 oz. Clear, pure quartz chips and small crystals not meeting the electronic-grade dimensional requirements are known by the Brazilian term lasca. They are used to produce fused quartz having wide application in laboratory equipment, as special glasses, for torsion suspension in scientific instruments, and as a source material for growing large artificial quartz crystals 18,35 Electronic applications far exceed all other uses in importance so any discussion of high-quality quartz crystals must be concerned almost exclusively with those functions. Historical Background Because of their ubiquitous character and natural beauty, quartz crystals have long been of interest and known to man. They have been found among early Egyptian and Chinese art forms and the Sumerians are believed to have fashioned seals, beads, and other jewelry from quartz crystals, perhaps 5,000 years ago. Also, American Indians made arrow heads and fashioned some simple objects of different kinds. The origin of the name quartz, although of Greek derivation, is uncertain. The Greeks appropriately applied their word for frozen water or ice, krustallos, to quartz. The present-day, large-scale practical applications of quartz crystals began in 1880-1881 when Pierre and Jacques Curie reported discovery of the "piezoelectric" effect. They found this effect first in Rochelle salt, a common product of grape-wine refineries, while studying crystal symmetry. Piezoelectricity is that property found in certain crystals, including quartz, whereby electrical charges of equal and opposite sign appear on opposite parts of the crystals when they are stressed. If equal and opposite forces are applied to two opposing prism edges of a single untwinned quartz crystal a positive electrical charge will appear on one edge and a negative charge on the other. The amount of the charges will be directly proportional to the force applied. This property seems to be intimately related to pyroelectricity

Jan 1, 1960

By LE B. GRAY

ALL meeting of the Chemical Section, National Safety Council, in Rochester, N. Y., put his hand on at least ten salient points that apply to safety in nearly any laboratory ; these are as follows : 1. Impress your laboratory worker at the start that he is dealing with powerful and dangerous-forces and that every experimental set-up must be studied from the stand- point of its fiber, electrical, explosive, and health hazards.

Jan 1, 1929