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By J. Chipman, J. B. Gero, T. B. Winkler

D. C. Hilty—This paper is a useful and timely addition to our store of quantitative data relating to manganese distribution between slag and metal in steel-making processes. For some time, many of us have suspected that the values of Kmn derived by Körber and Oelsen might be too low, and this paper now appears to confirm that suspicion. Application of the new constant to openhearth data should prove interesting. The manganese deoxidation curves of fig. 4 agree fairly well with direct measurements of isothermal solubilities of oxygen in liquid iron containing manganese that have recently been made at the Union Carbide and Carbon Research Labs., Inc. According to the solubility data just mentioned, however, the curves for 1550" and 1600°C lie much closer to each other than the authors have indicated. In other words, the solubility measurements suggest that the logarithm of the oxygen solubility is not a linear function of the reciprocal of the absolute temperature, as the authors have assumed for their calculations. It seems possible that this discrepancy may be due in part to the authors' use of the distribution coefficient, L,,, obtained from Taylor and Chipman's curve for the solubility of oxygen in iron as shown in fig. 2. Taylor and Chipman gave the equation of this curve as —6320 Log % 0 - ---T + 2.734 Their data, however, can be fitted equally well by a curve having the equation: 13.23 x104 1.18x10" Log % O = 36.350 -13.23x10 Moreover, this curve also fits the authors' oxygen distribution data somewhat better than does the linear curve of Taylor and Chipman. Its use in the derivation of Lo for calculation of the deoxidation curves by the authors' eq 15 causes the effect of temperature on the calculated curves of fig. 4 to agree quite well with the temperature effect that has been observed. An experimental determination of the temperature coefficient of the manganese reaction appears to be desirable. J. E. Stukel—Because the authors have done such an excellent job, my comments will be confined to additional information. Very shortly Professor T. L. Joseph and I will publish the results of a study of the reaction between molten manganese and silica. It was found that electrolytic manganese, melted in silica crucibles, reacted with the silica to form a silico-manganese alloy containing 18 pct silicon (1500°C) and a silica saturated MnO-SiO, slag. Therefore, the presence of silicon and its oxides in the Fe-Mn-0 system will affect the equilibrium. Carbon is also an important factor. The higher the carbon content of the iron the less ability manganese has to reduce silica. As a matter of interest, recently a study of the manganese equilibrium in carbon saturated iron and blast furnace slags was completed at Carnegie Institute of Technology. As a comparison to the present study, 2 to 5 hr were required to reach equilibrium and temperature was a much more important factor than slag composition in determining the (Mn)/(MnO) ratio. These results will also be published in the near future. It can be seen, therefore, that the results of this paper cannot be applied directly to openhearth studies without a degree of flexibility. J. Chipman (authors' reply)—With regard to the effect of silicon on the manganese constant, this effect is, of course, known. Much more data is needed in order to establish it accurately, and I hope we can look forward to having some accurate data on that. Mr. Hilty suggests that a three-term expression for the Taylor-Chipman solubility of oxygen in liquid iron might fit a little better than the two-term equation. I think that it would be too great a compliment to the precision of the data to employ a three-term equation, and I would still recommend the simple, two-term expression.

Jan 1, 1951

By J. P. Hirth, C. S. Hartley

A simple graphical technique is presented for rapidly determining the ratio of resolved shear stress on slip systems in single crystals to the applied stress (Schmid factor) for various simple states of stress. Master plots are presented which, when used in conjunction with an appropriate stereo-graphic projection, allow one to determine the Schmid factor for all slip systems in a crystal of given orientation. It is shown that one such plot suffices for simple tension or compression, flex-ural bending, and biaxial compression, while a combination of two different plots must be used for torsion and simple shear. STUDIES of the deformation behavior of single crystals are most valuable when the applied stresses are resolved onto the various slip systems of the crystal. A careful study of the available slip systems and proper selection of the state of stress used and the specimen orientation can then yield quantitative information about the probability of specific dislocation reactions, the strength of barriers to plastic flow, and the mechanisms of yielding and flow in general. It is the purpose of this work to analyze some common states of stress used in deformation studies and to present a simplified way of determining for these cases the ratio of the resolved shear stress on the slip systems to the applied stress (Schmid factor). I) CALCULATIONS We first define two orthogonal coordinate systems: one based on the specimen geometry (a right circular cylinder of radius, R, is considered here) and one based on the particular slip system of interest. The unit vectors and angles specifying the two coordinate systems and the relationship between them are listed in Table I. The relationships among the various angles and unit vectors are shown on a stereographic projection in Fig. 1. The transformation matrix between the (XI X2 X3) and (x'1 x'2 x'3) system is x1 x2 x3 X'1 a11 al2 a13 x'2 a21 a22 a23 x'9 a31 a32 a33 where in this case the direction cosines aij are given by a11 a12 a13 aij = a21 a22 a23 a31 a32 a33 sin 0 cos F cos 0 sin F cos 9 = -cos 0 cos F sin 0 sin F sin 6 [1] 0 -sin F cos (p In terms of Eq. [I.], the stresses sij, referred to the slip system, are determined from oij, referred to the specimen axes, by1,2

Jan 1, 1965

By A. K. Schellinger, R. D. Lalkaka

IF the ball mill is considered only from an energy standpoint, it can be thought of as a converter of kinetic energy into heat energy and surface energy. The law of the conservation of energy must apply to the ball mill as it does to any machine or process in nature. The heat energy output of the ball mill is apparent to any casual observer of the operating mill since the outflow pulp will be appreciably warmer than the inflow water and rock. The rock in the ball mill is crushed by shearing of its ionic bonding caused by some impact-induced stresses beyond the elastic limit. As the bonds holding the mineral crystal lattices together are ruptured, new surface area is created on each unit of which a definite number of unsaturated bonds exist. Such unsaturated energy of bonding may be termed the "surface energy," and is a potential energy figure. This created energy was withdrawn from the ball mill system and represents an absorption, or disappearance of heat. To reduce the size of the rock, surface area must be created and with it the at- tendant characteristic surface energies of the minerals concerned. Thus the creation of surface energy, from an energy viewpoint, is the creation of useful work by the ball mill. Because of the controversial nature of the energy efficiency figures for modern operating ball mills, it seemed worthwhile to approximate the ordinary magnitude of such efficiencies from the above viewpoint. This was done by an energy balance of the three aforementioned forms of energy, kinetic, heat, and surface energy, for two 9Y2x10-ft grate-type ball mills grinding cement raw materials. Kinetic energy input to the balls was approximated as closely as possible while the heat energy output was measured by means of a thermometer and water and rock flow rates. The assumption was made

Jan 1, 1952

IT will be recalled that when educational instruction for the mineral industry began at Freiberg, at the beginning of the eighteenth century, the original aim was to organize and systematize the procedures previously followed by young men in gaining familiarity with the technology then in use. There must have been many other ideas current, even then, as to just what a young man needed to learn in order to become capable of assuming responsibility for the supervision and direction of such technical work. The problem in Europe was decidedly different from that in nineteenth-century America, because some of the European mines were actually owned and operated by the governing authority and the others were supervised, regulated, and taxed by it. The American problem was the efficient performance of technical operations; the European one was regulatory supervision. It was natural, therefore, that in the development of educational processes in Europe stress was laid on those factors which conserved and protected the interests of the state. The study of mineralogy and geology, leading to correct judgments as to the workability and value of mineral deposits; assaying, which gave the means of quantitative measurements, as did surveying; chemistry, which furnished a better basis of understanding for assaying, mineralogy, and geology; and physics and mathematics, which are the bases for the understanding and efficient use of mechanical appliances, became the core of systematic instruction for the mineral industry. It was early recognized that men could learn more than was already known about all of these subjects and education took on that dichotomy which still characterizes it; the teaching of established knowledge to the unlearned, and that of extending of the bounds of knowledge, now loosely termed research, which after two and a half centuries of work still shows

Jan 1, 1941

By R. I. Jaffee, R. W. Wood, H. R. Ogden, D. N. Williams

D. W. Morgan, D. H. Polonis,and R Taggart (Uuivevsity of Washington)—Dispersion hardening in titanium-copper alloys is of particular interest to us in view of our current research activities in phase transformations in this system. We should like to raise questions concerning several points in the paper. The flow sheet for fabrication and heat treatment (Authors' Fig. 2) indicates that 0.045 in sheet is treated in air for a period of 30 min at 1625' F. Were any surface coatings used to reduce oxygen contamination at this stage? One might ask the same question about the 8-hr annealing at 1400F. Contamination during fabrication and heat treatment of such thin sections could be considerable without some protection. Although the authors state that no analyses were made, they note that contamination masks the distinction between base strengths of the different alloys. In this connection, what fabrication and heat-treatment procedures were used in obtaining the comparison specimens of unalloyed titanium? It would seem that oxygen contamination must cast doubt on the reliability of the proposed strength-mean free path relationship deduced from the data (Authors' Fig. 5). It is usual to evaluate dispersion hardening on the basis of yield strength rather than ultimate tensile strength, and accordingly we have replotted the authors' Fig. 1 to include yield strength. The yield strength data do not justify a discontinuity of 3 p at either 70" or 1000 OF. Can the authors substantiate their conclusion 1) with additional evidence? Otherwise it seems that they have succeeded only in pointing out the possibility of a linear relationship between yield strength (or Uts) and the logarithm of the nleall free path, comparable with that demonstrated for iron-carbon alloys (Authors' Ref. 2). Work in our own laboratories has shown that the hardness of the phase Ti,Cu is 235 Vpn, and that of a 1.5 pct (at.) (2 pct wt) supersaturated solid solution of copper in titanium is 190 Vpn. This small difference in hardness would suggest that Ti2Cu should not be a very effective dispersion-hardening phase. D. N. Williams, R. W. Wood, H. R Ogden, RI. L Jaffee (authors' reply)— This discussion brings out some interesting points with respect to the interpretation of our results, and also raises some questions regarding the experimental technique. We shall consider the latter questions first. Contamination during heat treatment was prevented by performing all heat treatments in argon-filled Vycor capsules. Fabrication was done in air, with the usually observed scaling. Scale was removed

Jan 1, 1962

By R. P. Carreker, R. L. Fullman, J. C. Fisher

CREEP tests are usually constant load tests. As deformation occurs, the cross section of the specimen changes so as to maintain approximately constant volume. Until necking starts, A _ l0 A0 - 1 where A is the cross-sectional area, 1 is the specimen length, and the subscript o indicates initial values. Thus, during a tensile creep test under constant load, the stress increases in proportion to the elongation. A A, 1, where S is the stress and F the load applied to the specimen.

Jan 1, 1954

From "Knots and Lashings," of Oct. 10, 1918, the military publication of Canadian Engineers' Training Depot, St. Johns, Que. During the early hours of Sunday morning last (the 6th inst.) there passed from our midst one of the most affable and estimable officers who, during our brief connection with the Depob, it has been our fortune to meet. Sidney A. Lang was born in Ontario in the year 1884 and lived in Toronto for a number of years. He ahtended Toronto University, where he displayed remarkable ability, and after graduating followed the profession of mining engineer. Being young and endowed with the spirit of adventure, he followed his profession in the mines of Chile and Peru; he could speak Spanish fluently. Always a reserved man, of refined tastes, it was difficult to induce him to relate some of his adventures in those countries so shrouded in mystery and romance. He joined the Canadian Engineers in Toronto as a sapper and shortly after came to this Depot.

Jan 1, 1920

By B. J. Kochanowsky

The primary use of a portable crusher, i.e., a crusher mounted on crawlers or tires, in the rock and mining industries is to reduce costs by permitting the substitution of conveyor belt haulage for truck or track haulage. The usual sequence of operations in surface mining is drilling, blasting, loading, haulage, and crushing. Haulage is normally accomplished by truck or track-mounted cars, the latter method being used for the longer distances. However, by using a portable crusher in the pit, the sequence of operations would be changed so that the crushing stage would occur before haulage (Fig. 1). Such a sequence would permit the use of conveyors to replace the more expensive truck or track haulage methods. Since most quarry and open pit operations normally require a crushing stage, the only additional costs incurred will be due to the investment required to purchase or construct a mobile arrangement for a crusher. But this factor has to be weighed against the advantages to be gained by conveyor haulage. As shown in Fig. 2, transportation of material by belt conveyor over short distances is less ex- pensive than by truck. The inclination of the belt has no effect on belt speed; consequently, the hourly tonnage moved remains the same. Conversely, the output rate of trucks as expressed in tons or ton- miles per shift decreases proportionally to the haulage speed, which is considerably slowed by the steepness of the road (Fig. 3a). Although maximum possible grades and maximum economic grades of haulage are greater for a belt than for a truck (over the same total lift), the longer haulage distances favor the use of trucks.

Jan 12, 1960

By Benjamin C. Craft, Frank Perkins

The wall-building properties of salt-water muds can be maintained at high temperatures by additions of gum karaya, gum ghatti, gelatinized starch, or commercially prepared starch. A germicide should be used to prevent fermentation. Introduction The behavior of drilling mud has received special attention from the petroleum industry within the past few years in numerous research projects dealing with such subjects as chemical treatment, gelation, and filtration characteristics. The importance and control of filtration, or water loss, is readily apparent* It affects the analysis of side-wall cores and interpretation of electric logs; it controls to a large extent the work of primary cementing, reduces the amount of expensive fishing, and permits the running of long strings of casing. It has been found that among the many factors that have an adverse effect on filtration, the presence of electrolytes, in general, and of salt, in particular, is outstanding. The effect is one of flocculation of the colloids due to neutralization of the negative charges on the clay particles. This reaction is further increased on the Gulf Coast because high temperatures reduce dispersion, to a minimum, causing increased flocculation in both fresh-water and saltwater muds. The problem of reducing water loss in salt-water muds by the addition of gums and starch at atmospheric temperature has been investigated,' and many successful field tests in West Texas indicate its solution. From the work of Byck2 it is concluded that no existing method will permit an approximate determination of the filtration rate at high temperatures from data taken at room temperatures. Filtration should be measured at the ternperature actually anticipated in the well, or at least at a number of lower temperatures and extrapolated over a small range. A laboratory study has been made of the chemicals available for the filtration characteristics of salt-water muds at high temperatures, and the use of germicides to prevent fermentation. Laboratory Investigations Procedure Since the purpose of this investigation was to compare several different gums and starches at elevated temperatures, mud from the same source was used for all the tests. Viscosity was measured in a Stormer viscosimeter at 600 r.p.m. and water loss was determined with a Baroid High-pressure and High-temperature Wall-building Tester3 at temperatures from 80' to 250°F. and at a pressure of 500 lb. per sq. in. for 30 minutes. The samples tested consisted of 150 grams of commercial Louisiana mud, 50

Jan 1, 1943

By Benjamin C. Craft, Frank Perkins

The wall-building properties of salt-water muds can be maintained at high temperatures by additions of gum karaya, gum ghatti, gelatinized starch, or commercially prepared starch. A germicide should be used to prevent fermentation. Introduction The behavior of drilling mud has received special attention from the petroleum industry within the past few years in numerous research projects dealing with such subjects as chemical treatment, gelation, and filtration characteristics. The importance and control of filtration, or water loss, is readily apparent* It affects the analysis of side-wall cores and interpretation of electric logs; it controls to a large extent the work of primary cementing, reduces the amount of expensive fishing, and permits the running of long strings of casing. It has been found that among the many factors that have an adverse effect on filtration, the presence of electrolytes, in general, and of salt, in particular, is outstanding. The effect is one of flocculation of the colloids due to neutralization of the negative charges on the clay particles. This reaction is further increased on the Gulf Coast because high temperatures reduce dispersion, to a minimum, causing increased flocculation in both fresh-water and saltwater muds. The problem of reducing water loss in salt-water muds by the addition of gums and starch at atmospheric temperature has been investigated,' and many successful field tests in West Texas indicate its solution. From the work of Byck2 it is concluded that no existing method will permit an approximate determination of the filtration rate at high temperatures from data taken at room temperatures. Filtration should be measured at the ternperature actually anticipated in the well, or at least at a number of lower temperatures and extrapolated over a small range. A laboratory study has been made of the chemicals available for the filtration characteristics of salt-water muds at high temperatures, and the use of germicides to prevent fermentation. Laboratory Investigations Procedure Since the purpose of this investigation was to compare several different gums and starches at elevated temperatures, mud from the same source was used for all the tests. Viscosity was measured in a Stormer viscosimeter at 600 r.p.m. and water loss was determined with a Baroid High-pressure and High-temperature Wall-building Tester3 at temperatures from 80' to 250°F. and at a pressure of 500 lb. per sq. in. for 30 minutes. The samples tested consisted of 150 grams of commercial Louisiana mud, 50

Jan 1, 1943

The Motor Truck Sections of the 20th Annual Automobile Shows of 1920, to be held in the 8th Coast Artillery Armory, New York, Jan. 3 to 10, 1920, and in the International Amphitheatre, Chicago, Jan. 24 to 31, 1920, will he the largest and most comprehensive exhibitions of the kind ever held. Approximately 125,000 sq. ft. of exhibition space has been alloted at each place and upward of seventy makes of motor trucks, together with trailers, pacts and accessories will be dis-played. In conjunction with these expositions, Highway Transport Conferences will be held, with sessions each afternoon and evening. Every important phase of highway transportation will be discussed by men recognized as qualified authorities. Various talks will he il-lustrated by motion pictures and stereoptican slides. Members of the Institute may apply for complimentary tickets to-S. A. Miles, Manager, 7 East 42d Street, New York City.

Jan 12, 1919

By H. C. George

With a growth of 718 per cent in the petroleum industry from 1901 to 1931, there was a corresponding increase in the demand for technically trained men in the industry. This was first met by increasing numbers of college graduates from the old established courses in chemistry, geology and engineering. However, a need began to be felt for scientists and engineers specially trained for the petroleum industry. In 1912 the University of Pittsburgh established the first department in any university in the world that offered major work in petroleum engineering and petroleum geology. In Europe, the first major work in petroleum engineering was offered in England in 1913 at the University of Birmingham. The University of California and Stanford University offered major work in petroleum engineering in 1915. Since that time at least 10 other American universities and colleges have offered major work and at least 12 others are now offering some courses dealing with petroleum and the petroleum industry.

Jan 1, 1934

F. C. HENDERSCHOTT,* New York, N. Y.-I am going to take, as the text of what I shall discuss, a portion of the second paragraph of Mr. Stanford's paper. It read as follows: "The most vital need of the management is for more brains. The logical course for an engineer ;in charge of an industrial organization is, therefore, to direct whatever forces may be at his command toward the development, training and guiding of-all the brains in his organization. This is easier said than done, for it involves the carrying on toward two objectives, the maximum of productive work and the development of the individuals, who perform it;" and the last sentence of the paper; "Industry has no greater asset than an intelligent workman." The United States of America, at the outbreak of the present war, had the best equipment of any nation in the world. That statement holds not only for our -shops and our transportation systems and our stores and our farms and our homes, but it holds generally.. There was no other nation in. the world that had so good equipment as the United States. There was no other nation in the world that could be called progressive that has such poorly trained workers as the United States. Even Norway, Denmark, Sweden and New Zealand ranked ahead of us. Now that is the, problem, generally speaking, and there was recognition of that fact, a growing recognition which-took form, and one of its forms was what we call the corporation school. Now obviously a corporation has no particular educational functions, but as is said in the closing sentence of Mr. Stanford's paper, or as is implied, an industrial institution is, after all, the reflection of the aggregate of the efficiency of the individuals who compose that organization. There is no way of getting away from that. If your individuals, from your president down, are efficient, if your individual has developed his brains, if he is a trained man, you have got an efficient organization, and if you haven't that condition, you have got weaknesses and your organization is no stronger than those weaknesses. I maintain that the same thing holds for a nation; .a nation is as efficient as the collective efficiency of the individuals who compose the nation, and no more so.

Jan 4, 1918

By Arthur F. Taggart, T. C. Fitt, A. W. Thomas

IT was noticed early by operators that high recoveries and flocculation of the sulphide minerals were closely correlated in agitation-froth flotation. Later, this readily visible flocculation was found almost invariably to be due to the binding together of the oiled sulphides by minute air bubbles, and is now known to be characteristic of pulps in which at least one of the mineral species is coated with an insoluble collecting oil. In 1930 it was reported1 that in differential flotation a correlation exists between Brownian movement of particles in the pulp and their nonfloatability, and that Brownian movement and dispersion are likewise correlated, whence it would appear to follow that dispersion of a mineral particle in a flotation pulp denotes a particle condition unfavorable to flotation. In 1934 it was postulated2 that Brownian movement, dispersion and nonfloatability all flow from the condition of the surface of the dispersed particles. It was also postulated at that time that the surfaces of dispersed particles are ionized, the ionized compound being a product of reaction between a component of the particle and a. component of the pulp, of a mass solubility of the general order of a fraction of a milligram to 15 to 20 mg. per liter. It was then further asserted, and has since been confirmed by Bankoff,3 that sulphides so conditioned with soluble collectors as to be floatable flocculate without the intervention of air bubbles as binding media. The present paper comprises an inquiry into the nature of the bound and counter ions in zinc sulphide dispersed by sodium arsenate. A part of its findings was mentioned in the 1934 paper above cited.2 The tests show that: I. When powdered granular zinc sulphide is immersed in aqueous solutions of sodium arsenate, arsenate ion is abstracted from solution and anchored to the solid surface, while sulphate and lower sulphoxy ions are concurrently displaced therefrom in substantially stoichiometric quantities. 2. The ion counterbalancing the anchored arsenate ion is zinc. 3. Dispersion and Brownian movement of zinc sulphide are concurrently maxima at an arsenate-ion concentration lying between 0.01 and 0.001-molar sodium arsenate. 4. Any condition or reaction that tends to remove the zinc arsenate coating from the zinc sulphide particles decreases dispersion and Brownian movement concurrently. EXPERIMENTAL Three samples of zinc sulphide were used. Lot I was C.P. zinc sulphide, washed well beyond absence of chloride, as shown by test with silver ion. Lot 2 was prepared by precipita-

Jan 1, 1943

By W. M. Pierce

CORRUGATED sheet zinc has been used abroad for a great many years as a roofing material. In this country it has been in use for about 10 years. From the outset it was recognized that zinc sheets required closer spacing of the supporting purlins than steel sheets. Exact data regarding safe maximum fiber stresses were not available, however, and on occasions the span used was excessive and the sheets sagged. This paper describes both service and laboratory tests to determine safe maximum fiber-stress values for various grades of zinc for use in calculating the proper purlin spacings for any gage and profile under given loading conditions. These tests consist of laboratory loading tests on full-size roof sections over extended periods of time; of actual roof installations erected in conformity with the indications of the laboratory tests and observed over a period of years; of careful determinations of the apparent elastic limit of several grades of zinc, and finally of static tests1 (so-called creep tests) to determine the rate of flow of zinc under a variety of static tensile stresses at definite temperatures. Certain of the individual tests extended over a period of more than two years.

Jan 1, 1929

By C. E. Westley, R. R. Beebe

Recent works by Plaksh et al.,1,2 Glembotsky,3 and others have renewed interest in the effects of oxidation on the surface activity of the sulfides. Since considerable supporting data are available on galena-potassium ethyl xanthate, this system is being studied at South Dakota School of Mines and Technology by contact angle measurement, using the technique of McGlashan and McLeod.4 The contact-angle method is well adapted to investigation of the influence of small amounts of oxygen on the establishment of a stable contact angle on galena in potassium ethyl xanthate solution. Samples of massive galena containing less than 0.001 pct Cu, 0.001 pct Ag, and 0.01 pct Zn are mounted in castable plastic and ground and polished manually in a glove box containing the desired proportions of oxygen and purified nitrogen. Oxygen and nitrogen contents of the test atmosphere are determined with an Orsatt analyzer. In this way a reproducible surface is created in contact with whatever oxygen concentration is desired. Water and all reagents are prepared and stored in the test atmosphere. An absorbent is used to control carbon dioxide that might be present. Final polishing is done with levigated alumina on a glass plate. The prepared sample is placed in the test solution and transferred to the contact angle apparatus in a sealed box, and the test is conducted while both sample and solution are maintained under a slight positive pressure of the test atmosphere. Table I gives the results of contact angle measurements made at various 02-Nz concentrations.5 Each value of contact angle is the average of at least six individual measurements made with different bubbles at different locations on the sample surface. A period of 20 to 25 min has been found by preliminary tests to be sufficient to permit develop- ment of maximum angle, and all measurements are made after at least this much time has elapsed. Exposure of prepared samples to pure water under the test atmosphere before exposure to the xanthate results in a small but measureable and consistent reduction in contact angle. This is particularly true in the oxygen-deficient atmospheres; for example, at 2.2 pct O2 such water contact reduces the average angle about 8" from that obtained by immediate testing in xanthate. The general trend of increasing contact angle with increasing oxygen concentration corresponds to the results of Plaksin et a12 The absence of diminish-ment of contact angle at very high oxygen concentration has been attributed to the high concentration of xanthate per unit of galena surface: At oxygen concentrations below 1 pct (the limit of accuracy of the Orsatt analyzer), no contact angle is obtained. Furthermore, no contact angle is obtained at any oxygen concentration in the absence of xanthate. This result seems to be in disagreement with those cited by Plaksin.1 Further work on the interaction of galena and potassium ethyl xanthate or a similar collector as influenced by oxygen is contemplated. The true nature of the interrelation is as yet unknown. For example, it is not known whether the governing oxygen reaction is with the mineral, with the reagent, or with both.

Jan 1, 1961

By W. L. McMorris

The Convertol process was first described in Germany by Muschenborn' in 1952. In the U. S. Fraser' reported this new process in 1953, and Brisse and McMorris" presented the results of a Convertol pilot plant at the Alpheus preparation plant in Gary, W. Va., illustrating the mechanics of the process by a series of sketches. The purpose of the present investigation was threefold: 1) to determine the relative effectiveness of various oils and hydrocarbons for recovering coal by the Convertol process, 2) to ascertain the behavior of coal pulps in this process under various operational conditions, and 3) to compare Convertol with flotation in the recovery of fine coals. APPARATUS, PROCEDURE, AND COAL SAMPLES In laboratory work with the Convertol process a Waring Blender equipped with a speed-regulating rheostat was used for wetting, conditioning, inversion, and retention of the coal pulp. A 5-in. International centrifuge was adapted to dewater the agglomerated clean coal product by installation of a 100-mesh screen inside the regular bronze basket of the centrifuge. Except where otherwise stated, the Convertol testing was performed by the following steps: 1) A 450 to 500-cc coal slurry, containing 24 pct by weight of solids, was agitated in the blender for 10 min at 100 rpm to insure complete wetting and mixing. 2) Eight percent by weight of oil was added to the coal slurry in the blender and agitated for 1 min at 11,000 rpm to result in the phase inversion or agglomeration of oil-coated coal particles. 3) The agglomerated coal slurry was poured onto a 100-mesh sieve and wet-screened for about 2 min to remove most of the ash and some of the water. 4) The material remaining on the screen was transferred into the centrifuge for final dewatering. 5) A portion of the clean coal was immediately weighed out for moisture determination, while the

Jan 1, 1960

C. P. Sandberg, London, Eng. 1 think we should all be grateful to the Pennsylvania Railroad Company, and to their chemist, Dr. Dudley, for spending so much time and money in order to solve an important question; nor are me less indebted to the public spirit which leads them to impart tlie experience thus gained. In Europe nothing similar has hitherto been done, either by a company or by any private individual. In England the great railway companies employ their engineers in other ways, and do not keep a chemist or specialist to study rails; bat even if they did they would probably not publish the results. The chief professional engineers are so occupied with their private practice of railroad construction generally, that they cannot be expected to devote their time and energies to so special a question. The German Railway Union has, in my opinion, missed the real object of its elaborate researches by falling into the error of specifying costly, impracticable tests for rails—tests at the same time which do not infallibly expose the impurities that may be in the rails under examination. There has, therefore, been nothing done on this side of the Atlantic in the way of exhaustive study to determine the best composition for steel rails. America should consequently have full credit for the enlightened example which she has set. I wish, however, to make a few remarks on Dr. Dudley's second paper,—& paper which follows very much upan the same lines of argument as the first red three years ago, upon which I have previously touched in my pabr on the same subject read at the meeting in August last. If Dr. Dudley had discovered a new metal he could hardly, I think, have taken wore pains to prove that he was correct in his first formula for the best chemical colnposition of steel rails. But I hare seen so much done in the way of proof by experiment that I am inclined to think that almost anything can be proved by experiments and by satnples. If Dr. Dudley would only give up his formula, which would not suit any country—not even America—

Jan 1, 1881

By J. P. Kimball

INCIDENTAL to a description of the hytlrographical basin of the Quemahoning in Somerset county, Pa., as a coal-field, I have, without a personal survey of the whole county, taken the pains to collate a synopsis of' leading facts, so car as available, relating to its coal resources. This is here presented, in view of an interest in the subject, growing out of a nearly central traverse of the county, in common with the southern tier of counties of the State, west of Blue mountain, by a new trunk line of railway—the South Pennsylvania. The political east-and-west boundaries of Somerset county, Pa., following the bold topography of Allegheny mountain and Laurel hill, are in common with the east-and-west boundaries of the First Bituminous Coal-basin formed by these ridges respectively, except the southeastern townships which lie on the eastern slope of Allegheny mountain. The nearly parallel anticlinals of Negro mountain and the so-called Viaduct axis stratigraphically divide the basin into three sub-basins, which, in order from east to west, are known as follows, viz. : I. Berlin-Salisbury (Eustern) Sub-basin : Between Allegheny mountain and Negro mountain, embracing the Berlin section of Barren coal-measures, the Salisbury section of Upper Productive coal-measures, and the Meyersdale and Garrett sections of Lower Productive coal-measures. 11. Somerset (Middle) Sub-basin: Between Kegro mauntain and the Viaduct axis, so called from the viaduct on the Conemaugh river, which there crosses it; embracing the section of Lower Productive measures of Mineral Point and Casselman on Castlenlan river, and of Somerset. 111. Johnstown- Confluence (Western) Sub-basin: Between the Viaduct stratigraphical sub-axis (which is less strongly marked topograpically in Somerset county as a ridge than in Cambria county), and the Laurel Hill graud axis. The synclinal of this sub-basin is crossed by tile Conemaugh near Johnstown, and by the Castleman

Jan 1, 1884

A few years later another gazetteer said of Virginia: "The Ouasioto Mountains are 50 or 60 miles wide at the Gap. These mountains abound in coal, lime and free-stone." The Gap was the Potomac River. "Copper, iron, black-lead, coal, marble, limestone &c are found in this country."' In the Morris papers, in Louisa and Goochland Counties, some records of operations in 1797 and 1798 have been preserved. These are: [ ]

Jan 1, 1942