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At the meeting of the Board of Directors held Tuesday, Feb. 18, 1919, there were present nineteen Directors and the Secretary of the Institute. The following officers were elected for the year: A. R. Ledoux, first vice-president; George D. Barron, treasurer; Bradley Stoughton, secretary; and the following committees: Executive Committee, Finance Committee, Library Committee, Committee on Papers and Publications, Committe on Membership. The personnel of these committees will be published in the Year Book. A vote of thanks was passed to each officer and member of the several committees that arranged the New York Meeting of the Institute. The meeting dates for the Board were arranged for the year. The report of the Treasurer was presented, also the report of the Auditing

Jan 4, 1919

By W. C. Phalen

E. G. SPILSBURY; New York, N. Y.-I would like to emphasize what Mr. Phalen says in his paper regarding the possible utilization of the waste acids in the West for the acid concentration of phosphate rock, and to call attention to the fact that this is already being done by Mr. Laist at Anaconda, who is producing concentrated phosphoric acid from these low-grade rocks. During the last year, he has not been able to carry this along to the extent he, had expected, owing to the tremendous demand which they have had for all the acid they can produce, so instead of having a. surplus of acid, as was expected, they are really short of this material for their electrolytic copper and zinc work.

Jan 4, 1917

Weiss Transit and Level The illustrations shown are the transits and levels manufactured by the Weiss Instrument Co. of Denver, Colo:, and they state that city and mining engineers are securing satisfactory results. It is claimed that their patented prismatic telescope gives increased illumination with an astronomical eye-piece. The prisms are set in a milled seat for this purpose, and cemented in so they can never come loose or out of adjustment. All adjustment for collimation is clone with the cross-hairs. This telescope is 8 in. long for magnifying power of 20 diameters against 12 in. for regular old style. The field is 1° 45' with a clear aperture of 1 1/8 in. The standards are 4 ¾ in. high from plate; to center of telescope axis. Weight 10 lb. Fig: 2. FIG. 1. FIG;. 3. The Light Mountain Transit of the same type, Fig. 1, has a telescope 6 ½ in. long, magnifying power 17 diameters; field 2° 15'; clear aperture 1 1/16 in.; weight 9 lb. The Mine Transit made by this ?company is interesting because it may be sighted directly down a shaft.. The principal advantage claimed for this type is the arrangement by means. of which vertical' sights can be had without an additional telescope.. As illustrated in Fig. 2 the telescope is in the position of a regular transit, and used exactly the same.

Jan 10, 1915

[Year of Election . 1944 .WALTER HULL ALDRIDGE New York. N. Y 1944 . SELWPN GWILLYM BLAYLOCK Trail. B.C.. Canada]

Jan 1, 1946

By W. G. Woolnough

Production of oil in Australia is negligible at present. A very small quantity of crude is being recovered from lean pumpers in Victoria, and a little activity is evidenced in Queensland, where two new wells were sunk during 1934. One of these, at Warooby Creek near Roma, obtained a noteworthy gas flow, but no oil production has been recorded. Geological investigation is going on in Western Australia, but no drilling activity is apparent. The "boom" in oil prospecting came to an end when the wave of depression swept over the country, and the investing public turned its attention actively towards gold. There is great activity in gold prospecting at present. I still maintain as strongly as ever that the prospects of obtaining flow oil in Queensland, Western Australia and Victoria are good, and that really scientific methods must ultimately succeed. Active and excellent geological work is being carried out in the Mandated Territory of New Guinea, and it is reported that drilling is likely to be undertaken next year. Matters in Papua are at a standstill. The question of extraction of oil from the oil shales of New South Wales and Tasmania is perennially active, and attempts to exploit this source commercially are renewed from time to time. Hydrogenation of coal is also receiving a good deal of attention.

Jan 1, 1935

By Yves Dardel

THE literature concerning the remelting of aluminum and its alloys is very rich. Unfortunately the greater part of the papers about this subject have no scientific value, for the theories or explanations are too often in opposition to the laws of physical chemistry. Furthermore only a few of the methods of purification1,2 are considered in the literature. Hence it has seemed necessary to the author to sketch a general theory of the purification of secondary aluminum. The purpose of the purification is to eliminate the impurities that the charges and the atmosphere of the furnaces bring into the bath during the successive remeltings. Indeed scrap as well as metal can be used when soiled with oil, greases, water, .. , if it has been sufficiently dried and contains oxides. At the melting point of the metal, the oils and greases are decomposed into their constituent elements H2, 02, H2O, C02, CO, CH4, and others. These gases are added to the corresponding gases in the atmosphere of the furnace. The impurities introduced into the metal during the remelting will accordingly be the products resulting from the action of these gases on the liquid bath. The quantity of hydrogen that is soluble in aluminum and its alloys is given by the relation of Sieverts3 as a function of its partial pressure PH2 in the atmosphere [m = K _%/PH, [I]] where K is a constant, which depends only upon the temperature and increases with it. The experiments of Röntgen and Braun4, Röntgen and Möller5, Bircumshaw6 and Winterhager7 have rendered it possible to determine the value of K, when the temperature is inferior to 1.000°K. One obtains: [log K = - 4,702.5 + 0.238 [2]] Besides its usual signification, the term PH2 represents also the internal pressure of dissolved hydrogen, since in the equilibrium, that is, when no gas exchange occurs between the two phases, the pressures of hydrogen in the metal and in the atmosphere must be equal. Eq I shows that when the partial pressure of H2 increases the amount of dissolved hydrogen in equilibrium increases, and that, if the contrary occurs, the quantity of H2 should diminish. However, if for any reason the diffusion of hydrogen is hindered and the total amount of dissolved gas remains constant while the temperature lowers, the internal pressure of H2 increases until it reaches the value of the hydrostatic pressure. At this point, bubbles of hydrogen appear in the bath and escape out of it. The amount of hydrogen in the metal is then limited by a maximum depending on the hydrostatic pressure, which is practically equal to one atmosphere. Indeed hydrogen does not accumulate in the form of a hydride appearing as a separate solid phase. However, even the mechanism of the solubility is not yet elucidated. One does not know exactly as yet, whether the

Jan 1, 1947

By Louis A. Panek

The purpose of this paper is to present a method of designing safe and economical arch structures that are to be constructed of concrete or directly of original earth materials. The experimental data used to illustrate the design method are taken from Bucky and Fen tress,1,2 and the application of the ideas presented by them is extended by obtaining an additional set of curves from which arch structures may be designed. This design method is based upon the following principles of similitude: A scalar model made of the same material as that of the full sized structure will behave similarly to its prototype if the density of the model is increased in the same proportion as its linear scale is decreased. Let R represent the scale or model ratio, namely, the ratio of a prototype linear dimension to the corresponding model linear dimension. The effect of increased density may be obtained by rotating the model in a centrifuge at a speed such that the centrifugal held exerts on the model an accelerative force R times the accelerative force of gravity. Under these conditions; (I) model unit stresses are equal to corresponding prototype unit stresses, (2) the ratio of the prototype deformation at a given point to the model deformation at a similar point is equal to the scale ratio, R, and (3) the model and the prototype will behave similarly within and beyond the elastic limits of strain. According to the above relations, such models can be used to solve the following problems: I. The dimensions of the most economical safe arch structure for a given load. 2. The miaximum safe roof span underground for given geologic conditions. The procedure is described briefly as follows. Tests are made by rotating in a centrifuge a number of models that repiesent a variety of prototype loads and dimensions. From the experimental data, curves are plotted to show the relations between these loads and dimensions. The curves are used to solve directly the problems stated above. Structural design is based upon the working (safe) stress of the material of construction, which is established by applying a factor of safety to the experimentally determined ultimate strength of the material. In conformity with this principle, each model is gradually loaded until failure occurs. A safety factor is then applied to the results. If a safety factor of 4 is used, a given model at failure represents a safe prototype, the linear dimensions of which are equal to one-fourth the model ratio at failure times the corresponding model dimensions. The safe model ratio is computed from the following formula: Safe R =(1/4)4p2n2r/g=p2n2r/g [I] in which: n = centrifuge revolutions per second at model failure; r = radius of rotation of the model in feet; g = 32.2 ft/sec2.

Jan 1, 1949

By Ernest Hersam

THE rate of output of a rock crusher is based upon a certain space relation, the calculation requiring that the size and position of the jaws, the principle of motion, and the speed of the machine be known. The result is a calculated maximum output. The purpose of this paper is to develop a method of calculating this maximum output, to judge the general applicability A utility of such a calculation, and, so far as possible, to record calculated values as a basis for the comparison of actual results, or for estimating the capacity of a new crusher or of a standard crusher working under new conditions. A method for calculating the capacity of crushing rolls, which has been in common use for a long time, is well presented by R. H. Richards.1 The output is conceived as a ribbon of rock, of which the breadth, thickness and length are governed respectively by the width of the rolls, the space, between them, and their peripheral velocity. The weight of the rock thus crushed in a given time can be calculated from its specific gravity, after applying a factor representing the percentage of voids in the hypothetical ribbon. The calculation of crusher capacity is made in a somewhat similar manner. While the action of rolls is simple, with few irregularities in operating conditions, in rock crushers the material advances intermittently, usually under the force of gravity alone, and is subjected to a variety of variable conditions. The effect of these variable influences upon' the calculation of capacity is now to be shown. In this paper, capacity will be discussed quite apart from any consideration of mechanical efficiency; that is, results will be stated not in terms of output per horsepower, but of output for a given machine when operated at a known speed, constructed and adjusted to receive material of a known size, and to yield a product having a definite maximum coarseness.

Jan 7, 1922

By Paul M. Tyler, Oliver Bowles

The extensive employment of nonmetallic minerals antedates the use of metals, but only within the last two decades has the production of nonmetals begun actually to keep pace with the complicated activities which characterize the so-called Machine Age. The economic changes ushered in by the Industrial Revolution were reflected first in an increased demand for metals and for fuels. In the modern sense, therefore, the nonmetallic mineral industries are new and afford new opportunities for engineer and economist alike. A certain amount of caution is indicated, therefore, before attempting to apply ready-made formulas to the problems of these industries. Economics is not an exact science. In the field of production technology where the number of variables is fairly well known, the principles of economics are readily applicable, but as the student proceeds through the province of marketing into the unexplored regions of psychology and sociology he must distinguish carefully between scientific reasoning and purely metaphysical speculation, even when the latter masquerades as economics. The present paper attempts to prove no preconceived theorems and is designed primarily to stimulate careful thinking on sundry neglected phases of these industries. An attempt is made to differentiate the general problems into single aspects which afford promise of being comprehended separately; also, some fundamental statistical data are presented, but merely to indicate a method of scientific approach applicable to more intensive studies. Definition Before discussing the economics of the nonmetallic mineral industries, it is appropriate to consider what we mean when we say "nonmetallic minerals." This term, inasmuch as it is merely a negative description, is somewhat loose and ambiguous and gives rise to questions in regard to minerals that, like chromite or bauxite, are alternatively classed either as nonmetallic or as metallic minerals (or ores). The chrome ore used to make ferrochrome for steel manufacture is undoubtedly metallic in character; similar material destined for use as a refractory in the same

Jan 1, 1934

By Jan Wolski

Today's rapidly shrinking world requires a common language of measurements, a consistent system which could be used by everyone. The S.I. system of units is generally accepted as such and is already in use by a great majority of nations in the world. The change to S.I. units is also slowly taking place in U.S. engineering practice. The transition period is difficult and long because it takes time to get familiar with the new system, to start "feeling" values in new units. Instruments, formulas, computer programs, survey grids, etc. have to be converted or exchanged. The transition period should be used not only for substitution of units, but also for rationalization of presently used calculation methods. This paper examines the major parameters of mine ventilation from the above point of view and discusses a system which is much simpler and more consistent than the American Unit System still in use in the United States. In October 1979, the Society of Mining Engineers of AIME decided to introduce the S.I. unit system in all its publications including the periodical "Mining Engineering", and since February 1980 the system has been used consistently, not only in SME publications but in all conferences and meetings organized by this Society. The authors have no intention of explaining the details of the S.I. system in general. Any reader can find this information in many available publications and conversion tables, and in particular in the ASTM Standard for Metric Practice, E380-79. A comparison is made between various units used in mine ventilation from the past and those presently in use. This will allow an easy translation from one system to another, important when reading publications from abroad. S.I. and customary U.S. formulae are shown side by side for easier visualization of similarities and differences. Recommendations for the necessary steps in order to switch from American to S.I. units conclude the paper.

Jan 1, 1982

By H. I. Kaplan, C. Laird

Pulsating contpresslon experiments have been carried out on coppev single crystals in order to test the adequacy of mechanisms which have been suggested for stage I cvack grouth when tension-compression loading is the mode of- applying stress. Although dejorrrzation continues slowly for many millions 01 cycles under Pulsating compression stresses both within slip bands formed in the first cycle and by the creation of new bands, the morphology of these bands is not typical of fatigue slip bands in general and neither initiation of cracks nor propagation of artificially induced cracks was observed. It is therefore concluded that 1) initiation and growth of cvacks in fatigue is a consequence of repeatedly reviersed, microplastic deformation rather than intermittent, unidirectional deforma-tion, 2) gvowth of- cracks in polycrystalline specimens FAILURE of a plain specimen subjected to cyclic tension-compression stresses is known to take place by two stages of cracking.1,2 The first stage is characterized by propagation along slip planes roughly at 45 deg to the stress axis, in the outermost layers of the specimen, and at a rate of the order of angstroms per cycle. The average macro orientation of a stage I crack is normally at right angles to the stress axis,3 however, except in a few cases, e.g., single crystals in suitable orientation, when both the micro and macro directions of propagation are at 45 deg to the axis. After a stage I crack has penetrated to such a depth that the stress on the remaining section of metal is significantly increased, stage II crack propagation succeeds stage I, at right angles to the stress axis both micro and macroscopically. Direct evidence of the processes occurring during a subjected to pulsating compression stresses is caused by the setting-up of local tensile stresses due to interactions between grains, and 3) both unslipping mechanisms and operation of the "plastic blunting process " within a single slip band are adequate descriptions 01- stage I growth, being fundamentally similar. The slip mode of a material, however, is considered to control whether unslipping or the plastic blunting process takes place. Thus materials of planar slip mode fauor unslipping while those hacing a wavy mode, and capable of cross slip, can fail in stage I by the plastic blunting process. Similarly, and perhaps more importantly, reversed torsion and tension-compression modes of applying stress may be expected to cause the unslipping mechanism and the plastic blunting process, respectively. single stress cycle4,5 shows that stage II crack propagation takes place by a repetitive plastic rounding and closing of the crack tip. This mechanism has come to be called the "plastic blunting process".6 On the other hand, the extreme smallness of the phenomena occurring in stage I growth prevents elucidation of its mechanism by direct observation. Many suggestions have been proposed for this mechanism,'"-" most of them involving some kind of random or systematic unslipping process. It is possible, however, that the mechanism of stage I growth is essentially the same as that of stage 11, but occurring on a much smaller scale.6 In this situation, it has been observed that cracks propagate along slip bands comprising dislocation cell structures and bounded on either side by regions of different dislocation density and distribution." Since there is evidence that such bands are softer than their matrix, * it may be expected that the plastic blunting process occurs within a single slip band during stage I growth, rather than on two gross bands as in stage 11, when the acting stress is greater.= The blunting of the crack tip allowed by coordinated

Jan 1, 1968

By Donald N. Rosenblatt

I would like to commend the author on his description of Pinto Valley's plant, and its interesting innovations. The author's discussion of 18 ft in diameter by 21 ft long primary ball mills (the largest wet ball mills made to date) is of considerable importance to those who have been engaged in the field of studying ball mill liner wear as it relates to various grinding installations. While it is stated that the mills have operated on a fixed tonnage and therefore it has been difficult to determine the best liner pattern, calculations from the data in the paper indicates that for mills 1, 2, 5, and 6, the tonnage per hour varies from a low of 223 for mill No. 1, up to a high of 314, for mill No. 2, while mills 5 and 6 calculate 285 and 246, respectively. Analysis of the wear patterns for the single wave liners used in mill No. 1 as compared to the double wave liners in mill No. 2, suggests that the author's data may tell more than he suspects about liner wear to be expected and thus what should be a best pattern selection from what may appear to be only limited hours of operation. [Fig. A] is a reproduction of author's [Fig. 10], to which wear forecast patterns [F-1 and F-2] have been added. Forecasts are based on many previous studies of large diameter ball mill operations over many years of field service. Calculations from the first-wear pattern provide an initial wear rate of only 13 lb of liner per 100 sq ft of shell liner surface per day, or 0.031 lb per to: ground. However, the second wear pattern is ac-

Jan 1, 1978

By T. A. Read, M. W. Burkart

The crystal geometry of the cubic-tetragonal interface after partial transformation of an indium-thallium alloy single crystal is described and a general theory is presented. The effects of applied stresses on this transformation are interpreted and the latent heat of transformation is obtained from observations of transformation under stress. A DIFFUSIONLESS phase transformation between face-centered cubic and face-centered tetragonal structures has been reported for the indium-thallium system by Bowles, Barrett, and Guttman1, 2 The transformation takes place at approximately 105 "C at 18 atomic pct Tl and 25°C at 23 pct Tl. In their study, Bowles, Barrett, and Guttman used poly-crystalline samples whereas in the present study single crystals were used to eliminate the transformation constraints imposed by adjoining grains. The use of single crystals made possible a comprehensive study of the effect of stress on the transformation. In the course of the work, it was possible to formulate a new method of analyzing dif-fusionless transformations (presented in this paper) which permits calculation of the geometry of the interphase interface from a knowledge of the crystal structures of the initial and final phases. The specimens were prepared from chemically pure thallium and 99.97 pct In which were weighed out to produce 3 to 4 grams of alloy of the desired concentration. The metal was placed in clean fused silica tubing, then melted, degassed and sealed under vacuum. (To obtain single crystals, it was found that both degassing and extreme cleanliness were essential.) Single-crystal specimens were grown by a modified Bridgman technique.8 pecimens were removed from the tube by dissolving the quartz in concentrated hydrofluoric acid which attacks the specimen very slowly. The specimen then was polished mechanically to produce four flat surfaces, electropolished, and annealed at 140°C for 48 hr. The electropolishing solution used was that described by Bowles, Barrett, and Guttman and the polishing was carried out on both the high and low temperature phases of the alloy. The high temperature polishing was done at 110°C with a stainless steel cathode. Visual Observation of the Transformation in Single Crystals A visual study of the transformation was made on specimens which had been electropolished in the high temperature phase. The specimens were supported on the stage of a metallograph by an electrically heated holder which contained an opening for observing the specimen. Visual evidence of transformation was found in the presence of an interface which separated the two phases. The interface plane defines the boundary of the phase undergoing transformation and manifests itself by the sharp change in angle between the surface of the specimen and the incident light at the juncture of the two phases. On slow cooling, well-annealed specimens transformed from the face-centered cubic structure to the face-centered tetragonal structure by the motion of a single plane interface which traversed the specimen from one end to the other. Upon heating, the interface moved back in the reverse direction. The interface could be started, stopped, or reversed at will. A temperature hysteresis of about 31/2oC was observed in the reversal of the interface. Holding an interface stationary caused it to disappear completely in most cases, whereas in other instances the interface became less distinct depending upon its orientation. The interface could be made to reappear by changing the temperature of the specimen. The low temperature tetragonal structure exhibits only the fine markings or subbands reported by Bowles, Barrett, and Guttman and is illustrated in Fig. 1. These subbands are twin-related. Back-reflection Laue patterns show the breakup of the cubic spots into pairs of spots corresponding to the twin orientations of the tetragonal phase.

Jan 1, 1954

By J. C. Purcupile, R. L. Morris

Present methods of roof support require that first a hole must be drilled, and then a toggle belt or grouted resin bolt be set. Automating this system is very difficult. Therefore, we decided to develop a system which would insert pins into the roof in one step. We think that this type of system can be automated much easier. It would then speed up the roof bolting operation and eliminate the need for a man to work under unsupported roof, making roof bolting a much safer job. There are two ways that a pin can be inserted in a mine roof without drilling a hole. It can either be pushed in, using a very high, constant axial force; or it can be hammered in like a nail. The former method involves very high compressive stresses in the pin, and requires complicated machinery to prevent buckling. Since hammering the pin does not require high axial forces buckling is not as likely. Also, experiments have shown that there are no problems associated with getting the pin to go in straight. We chose to develop the second method. While investigating methods for hammering a pin into a mine roof, we learned that piles were being driven 10 times faster than by conventional methods with a method called "orboresonance." We decided to turn the pile driver upside down, and drive pins up into the mine roof. Sonic Pin Setting Machine The machine consists of a steel bar supported at the nodal points of its first mode of transverse vibration (Fig. 1). A mechanical oscillator, driven by a hydraulic motor, is attached to one end of the bar. This provides the forcing function for the vibrations in the bar. The hydraulic power is supplied by a portable unit. When the forcing function is near the natural frequency of the bar, large amplitudes of vibration occur and require little power input. An anvil is attached to the bar at a point of maximum deflection, providing a means for striking the pin. Since the bar is being driven near its natural frequency, it takes little energy to accelerate the bar back and forth between each hit. This means that most of the power being put into the bar is going into driving the pin. This is unlike conventional pile drivers which use most of their power to accelerate the hammer back and forth between hits. The resonant frequency of the bar we used is about 250 Hz, which is in the audible range, hence the term "sonic pin setting machine." The system benefits are: (1) elimination of the two-step drilling and pin-setting roof bolt operation, (2) increased speed, (3) more intimate contact between the formation and bolts, (4) less expensive roof bolts, (5) higher integrity, (6) potential for automatic operation. Modifications During the months from Oct. to Dec. 12, 1974, under U.S. Bureau of Mines grant No. 00144104, "Projects on Coal Extraction," six members of the senior class at Carnegie Mellon University designed and built the experimental machine. They drove three pins into the Safety Research coal mine at Bruceton, Pa., and determined that the project was worth continuing. In January 1975 we began making modifications and repairs in preparation for a more extensive program of testing at Bruceton. The major items were: 1) Design and build a collapsible pin guide to keep the pin parallel with the line of travel of the lift table. 2) Move the anvil to the center of the bar. 3) Refinish the nodal holes and install new node pins and bushings. 4) Realign the bar in its frame. 5) Install a relief valve on the lift unit to control the upward force. The upward force that we exert on the pin is relatively small, so there is no tendency for it to buckle. This means that all we need to do is hold the pin straight during its initial penetration. This allows the bushing to travel up and down in a straight line. At the beginning of penetration, the bushing

Jan 1, 1977

By William L. Boyd, Eugene L. McCarthy, Laurance S. Reid

Proper control of the moisture content of natural gas is essential to reliable operation of gas transmission and distribution facilities serving northern markets. The moisture content of natural gas is usually determined by dew point measurement at the existing pressure. For any gas of constant moistrire content. the dew Point varies with the pressure. A correlation of the data of several investigators is prezented in graphical form by the authors. These data were correlated by the authors and F. M. Townsend, C. C. Tsao. M. I). Rogers. Jr.. and J. A. Porter. graduate students in chemi(.a1 engineering at the University of Oklahoma. Of articular interest are the hitherto unpublished low temperature data observed by Wickliffe Skinner. Jr., which are included in this correlation. PRESENTATION OF DATA The problem of interpreting water dew points, or saturation temperatures. of natural gas in terms of specific moisture con-tent has increased in importance during the past decade bec.arl.;e of extensive development.; in the transmission and petro-chemical phases of the natural gas industry. Virtually all gas transported to northern and eastern markets must be dehydrated to a low water vapor content to prevent hydrate formation in transmission and distribution lines and resultant interruption.; in gas deliveries. Complete dehydration is required in certain phases of tile petro-chemical industry involving low-temperature operations. It is a well-known fact that the water vapor content of pure hydrocarbon vapors and their mixtures at superatmospheric pressures cannot be predicted with accuracy by assuming validity of the ideal gas laws." Earlier interest in the general problem was concentrated on the water vapor content of pure hydrocarhons and hydrocarbon mixtures in the pressure and temperature ranges common to gas and oil producing reservoirs in order to obtain fundamental data for the improvement of production techniques and the furtherance of reservoir studies. Excellent data are published for pressures ranging from atmospheric to 10,000 psig and for temperatures ranging from 100° to 460° F4,9,10,11 and are found to be in close agreement. However, experimental data at high pressures and temperatures below 100°F are comparatively limited in scope. Experimental data in the lower temperature range have been reported by Laulhere and Briscoe.8 Deaton, et al,2,3 Hammerscllmidt,5,6 and wade," In general, the pressures employed in these investigations ranged from atmospheric to 1.000 psig while temperatures ranged from 32° to 120°F; i.e., the usual conditions encountered in gas transmission line operations, Additional data were reported by Russell, et al,12 at pressures as high as 2.000 psig and covering a rather narrow atmospheric temperature range. In 1947, Hammerschmidt published a correlation of all available data,' in which the water vapor content of gases at saturation. under high pressure and low temperature. was predicted by extrapolation. In 1948, Wickliffe Skinner. Jr.. presented data on the moisture content of a low nitrogen content gas at low temperature and at pressures ranging upward to 1.500 psia.1-3 Comparison of Skinner's experimental data with the extrapolated data of Hammerscllmidt revealed an appreciable variation in the lower temperature range. emphasizing the need for a new correlation which would rely on Skinner's data at lower temperatures. Careful scrutiny of available data suggested that presence of an appreciable quantity of nitrogen in a gas mixture may affect its saturated moisture content so that data obtained from gases with more than three per cent nitrogen were not used in this correlation. CORRELATION OF DATA Data employed in this correlation are presented in Table I. The data of Dodson and Standing.4 McKetta and Katz,9 and Olds, Sage and Lacey10 were compared and found to be in close agreement so that the data of Olds. et al, re-plotted in a more convenient form by the Humble Oil and Refining Co.,' were used for temperatures of 100°F and above. Skinner's data were used for temperatures below 40°F. Between these intermediate temperature limits, the data of Hammerschmidt.7 Wade" and extrapolated data of Olds. et al.1 were tabulated

Jan 1, 1950

By HAROLD A. TITCOMB

TOWARD the close of 1925, a British geologist, T. Landell Mills, brought to the notice of .A. Chester Beatty and selection Trust Ltd. certain mineral areas in southern Yugoslavia. Mills' data, which included rough maps and preliminary reports by' a Yugoslav engineer, Jules Draskocy, appeared interesting to Reatty, and early in 1926, I, with three British assistants, proceeded to Serbiaand commenced the investigation of several groups of ancient mine workings. They were found to be extensive and the geological conditions-schists, limestones, and andesitic intrusive-favorable for mineral deposits. At Stan Trg, on the Trepca Concession, five rniles east of Kosovska Mitrovica, an ancient filled adit was found, a shelter-hut erected, and work started in reopening this adit.

Jan 1, 1936

W. R. Ingalls, since 1905 editor of the Engineering and Mining Journal, retires from that position with the issue of Mar. 22, to open offices in New York City as a consulting engineer. The severing of this connection .will not be complete, however, as Mr. Ingalls will continue as consulting editor, and will handle the metal-market quotations in the Journal which are now the accepted authority for the government settlements of ore importations and the basis of practically all the ore settlements between miners and smelters throughout' the country. No greater compliment can be paid to Mr. Ingalls than this, unless it is the recognized fact that these quotations have been made what they are by his ability and his integrity, which secured for him channels of information vital to the accurate estimating of the market, but denied to anyone else. The Journal, under the. strong hand of Mr. Ingalls, has always been the acme of ethics in technical journalism, and the best wish that can he given to his successor, not yet announced, is that the Journal may long continue to live up to the standards not originated, but so consistently maintained and strengthened by Mr. Ingalls. His spelter statistics are accepted as authoritative wherever the English language is read and zinc ore is mined. He has found time during his very arduous years on the Journal to he the author of several works on the resources and metallurgy of zinc, lead, cadmium, etc.; for 5 years was the editor of Mineral Industry; and was consulting engineer for the Bureau of Mines and joint author of their voluminous and authoritative work on mine safety rules. His retirement from the Journal is a distinct loss to every one of the Journal's readers individually and to the profession as a whole. Universal good wishes go with Mr. Ingalls to his new field, which has for a long time been offering him professional attractions that his confining editorial work has not permitted him to accept.

Jan 4, 1919

By Ernest A. Hersam

The rate of output of a rock crusher is based upon a certain space relation, the calculation requiring that the size and position of the jaws, the principle of motion, and the speed of the machine be known. The result is a calculated maximum output. The purpose of this paper is to develop a method of calculating this maximum output, to judge the general applicability or utility of such a calculation, and, so far as possible, to lecord calculated values as a basis for the comparison of actual results, or for estimating the capacity of a new crusher or of a standard crusher working under new conditions. A method for calculating the capacity of crushing rolls, which has been in common use for a long time, is well presented by R. H. Richards.' The output is conceived as a ribbon of rock, of which the breadth, thickness and length are governed respectively by the width of the rolls, the space between them, and their peripheral velocity. The weight of the rock thus crushed in a given time can be calculated from its specific gravity, after applying a factor representing the percentage of voids in the hypothetical ribbon. The calculation of crusher capacity is made in a somewhat similar manner. While the action of rolls is simple, with few irregularities in operating conditions, in rock crushers the material advances intermittently, usually under the force of gravity alone, and is subjected to a variety of variable conditions. The effect of these variable influences upon the calculation of capacity is now to be shown. In this paper, capacity will be discussed quite apart from any consideration of mechanical efficiency; that is, results will be stated not in terms of output per horsepower, but of output for a given machine when operated at a known speed, constructed and adjusted to receive material of a known size, and to yield a product having a definite maximum coarseness.

Jan 1, 1923

By Ernest A. Hersam

The rate of output of a rock crusher is based upon a certain space relation, the calculation requiring that the size and position of the jaws, the principle of motion, and the speed of the machine be known. The result is a calculated maximum output. The purpose of this paper is to develop a method of calculating this maximum output, to judge the general applicability or utility of such a calculation, and, so far as possible, to lecord calculated values as a basis for the comparison of actual results, or for estimating the capacity of a new crusher or of a standard crusher working under new conditions. A method for calculating the capacity of crushing rolls, which has been in common use for a long time, is well presented by R. H. Richards.' The output is conceived as a ribbon of rock, of which the breadth, thickness and length are governed respectively by the width of the rolls, the space between them, and their peripheral velocity. The weight of the rock thus crushed in a given time can be calculated from its specific gravity, after applying a factor representing the percentage of voids in the hypothetical ribbon. The calculation of crusher capacity is made in a somewhat similar manner. While the action of rolls is simple, with few irregularities in operating conditions, in rock crushers the material advances intermittently, usually under the force of gravity alone, and is subjected to a variety of variable conditions. The effect of these variable influences upon the calculation of capacity is now to be shown. In this paper, capacity will be discussed quite apart from any consideration of mechanical efficiency; that is, results will be stated not in terms of output per horsepower, but of output for a given machine when operated at a known speed, constructed and adjusted to receive material of a known size, and to yield a product having a definite maximum coarseness.

Jan 1, 1923

By W. Denham Verschoyle

IN designing a pocket instrument whereby any given horizontal or vertical angle may be closely approximated, the following points should be kept in view, if general utility is aimed at 1. The instrument should be light and compact, so that it can be carried in the pocket, or in a sling. 2. It should be capable of observing any angle whatever, horizontal or vertical. 3. Since time is often an important consideration in making a preliminary survey, it should be capable of giving the horizontal and vertical angle at one observation. I do not know of any instrument that will fulfill these requirements, except the one here described. Where the depression- or elevation-angle of the distant object, whose bearing is required, exceeds 50 or 60 degrees, it becomes difficult or impossible with a prismatic compass, for instance, to obtain accurate results; and since it frequently happens, particularly in mining, that much work requires to be done beyond that limit, it is obvious that an instrument which can be used to observe a high angle just as easily as a low one, if not absolutely a necessity, will at least be a great convenience. How this " pocket transit " attains to the required degree of universality will be understood from the diagram, Fig. 1, in which B is a beveled, graduated circle, attached to and freely revolving about the center of the magnet A. Light falling on B is reflected through a window in F (the compass-box), along the line AC, and is again reflected back to the eye at D by the prism C. By a simple arrangement, the sight-line DCE can be completely revolved in the vertical plane DE, which is normal to AC. It is clear, then, that no matter through what vertical

Jul 1, 1907