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By M. A. Rigdon, R. E. Grace

The dissociation of cupric oxide to cuprous oxide and oxygen was studied with a microbalmce technique at 700" to 750°C. In this temperature range the dissociation pressure of the reaction 2CuO= Cu2O + 1/2 O2 was: The theory of near-equilibriwm reaction rates predicts a linear relationship between reaction rate and the Gibbs free-energy change for small values of AF/RT. This correlation is found to be valid for AF/RT = -0.1 or approximately 200 cal per mole away from equilibrium. THE theory of reaction rates near equilibrium as developed from classical thermodynamics suggests a small range of linear behavior between the overall reaction rate and the free-energy change accompanying the process. The extent of this linear correlation is generally unknown, even to the order of magnitude. The idea of linearity is also found in the formal mathematics of coupled transport phenomena, e.g., chemical diffusion, thermal diffusion, thermoelectricity, and so forth. The linear array of forces and fluxes which leads to various main and cross coefficients is predicated upon linearity between reaction rates and the bulk thermodynamics which govern the process. The general case in reaction kinetics is well-known: the magnitude of the free-energy change does not cor- relate with observed reaction kinetics, irrespective of whether the process occurs by diffusion or chemical reaction or both. The real need is to investigate specific reaction paths near equilibrium in order to learn of the limitations in attempting to correlate reaction rates and thermodynamics. It is the main purpose of this paper to examine the dissociation kinetics of cupric oxide under conditions of known driving force where the dissociation process is likely to occur by chemical reaction. A secondary objective is to obtain equilibrium data for the CuO-Cu20-O2 system. In a prior paper Edmiston and race' investigated reduction kinetics of wustite in H2-H2O gas mixtures. The present study was carried out in oxygen according to the following reaction:

Jan 1, 1969

By Douglas Bunting

THE first presentation of this paper was before the Pennsylvania Anthracite Section of the Institute in May, 1914, after which a committee was selected to verify and add to the data contained in the original paper. The author is indebted to G. W. Engel, H. W. Montz, R. V. Norris, and H. H. Otto, of this committee, for additional information. I also wish to acknowledge the courtesies extended me by a number of the mining companies for information relative to accidents, systems of proving, and mining practice. The paper should bring forth additional criticism and recommendations, which will be of value in establishing future practice relative to this subject. Throughout the northern anthracite field of Pennsylvania glacial and alluvial deposits of sand, gravel, and clay exist in varying quantities. The extent and character of these deposits are described by N. H. Darton in Bulletin 45 of the U. S. Bureau of Mines, entitled, Sand Available for Filling Mine Workings in the Northern Anthracite Basin. It is estimated that the northern field contains 10,000,000,000 tons of these deposits, or a sufficient quantity to cover the 176 square miles of coal area to a depth of about 25 ft. These deposits of sand, etc., overlying the coal measures attain a maximum depth of more than 300 ft., and are usually saturated to such an extent as to render them semi-fluid. It is .this condition of fluidity that limits the mining of coal seams cropping in or in close proximity to these deposits, and it is in the interest of safer and more efficient mining methods under these conditions that the study of this -subject is here presented. The dangers incident to mining under deep deposits of sand have long been realized by operators in the northern anthracite field, and much has been done to prove the contour of the rock and vein croppings underlying these water-bearing deposits of sand and gravel.

Jan 1, 1915

By C. M. Ball

The magnetic concentration of iron-ores has been so often and so widely studied and discussed among the members of the Institute that any remarks concerning its general importance, from an economic standpoint, would be superfluous; but it is thought that a description of the Ball and Norton ore-separator, designed for cobbing and separating magnetic iron-ores, indicating its essential differences from other machines and the advantages claimed for it, together with some account of recent results obtained in its application to the concentration of such ores, will prove of interest. This machine is the joint invention of Mr. Sheldon Norton, of Hokendauqua, Pa., and the writer, and has been patented in the United States, Canada, and other countries. Of the accompanying illustrations, Pig. 1 represents a longitudinal vertical section of the perfected ore-separator, adapted for separating fine ore, and Fig. 2 the same, adapted for cobbing ore of the size of stove- or chestnut-coal. The two designs are identical in principle, and vary from each other in minor details only. The apparatus consists of a partially-closed chest, having an opening at f, from the feed-hopper, h, through which the ore is delivered to the machine from an ore-pocket or storage-bin provided with means for regulating the flow of ore, so that, when the machine

Jan 1, 1891

By C. M. Wayman, G. R. Srinivasan

A metallographic study of the isothermal products formed between 750° and 285°C was made in an Fe-7.9 wt pct Cr-1.11 wt pct C alloy, and a time-temperature-transformation diagram was determined. The study shows that the austenite decomposes into three different products: pearlite above 540°C, ferrite and carbide between 540° and 300°C, and lenticular bainite below 300°C. No upper bainite forms in this alloy. The results are discussed in terms of carbon diffusion models for upper bainite formation. AUSTENITE transforms into several products depending on the temperature, composition, and rate of cooling, and the various transformation products have been a source of controversy for a long time. Since the classical study of Davenport and ~ain' extensive work has been carried out. The present study concerns the isothermal transformations in an alloy which was used for a detailed investigation of bainite crystallography and provides information supplementary to the work of Lyman and Troiano who studied austenite decomposition in steels containing 1 pct C and varying amounts of chromium. Their work showed that increasing the amount of chromium in high-carbon steels had the effect of depressing the B, temperature and of shifting the TTT curves to longer times and lower temperatures. They further found that if the chromium content is increased in a 1 pct steel to about 9 pct no bainite would form even after a period of 100 days. However, a preliminary investigation by the present authors showed that bainite plates do form in steels containing about 8 pct Cr and 1 pct C. In view of this and some results from a thin-foil electron microscope investigation of the bainite formed in the present alloy: it was considered desirable to investigate the other isothermal products as well. EXPERIMENTAL PROCEDURE The alloy used in the present investigation was obtained from a triply vacuum-melted ingot prepared from high-purity materials. Chemical analysis for the alloy verified the composition to be Fe-7.9 wt pct Cr-1.11 wt pct C. Metallographic observations were made on i by i by « in. specimens which were aus-tenitized at 12 50°C for 50 to 60 hr in evacuated quartz capsules and then water-quenched. Since the M, temperature for this alloy is below room temperature, the homogenizing treatment produced a completely austenitic structure consisting of very coarse austenite grains (ASTM #0-1). Several samples of the austenitized specimens were metallographically prepared and observed for any proeutectoid carbide separation. It was found that all the carbon was in solution. The water-quenched specimens were upquenched and given isothermal treatments at temperatures between 285" and 750°C for varying periods in molten salt or lead baths. The specimens were then water-quenched, and those showing less than 5 pct transformation were used for plotting the beginning of the austenite decomposition. To ensure the removal of the disturbed layer, the mechanically prepared specimens were electropolished in a 1:6 HzS04, CHSOH solution for 10 to 15 sec at 20 v. Final polishing was done with a vibratory polisher using 0.05-p alumina. Various etchants including nital, ferric chloride, and hot ferricyanide (Murakami's reagent) were used to bring out details in the different transformation products. The ferricyanide etch was used whenever the preferential etching of carbides was desired.

Jan 1, 1969

By Frederick Prime

IN this second supplementary list no titles to which an * is. Pre-fixed have been seen by the compiler; and he will be most thankful to have, any omissions or inaccuracies in the list sent to him to be published as a third supplement in the next volume of- the Trans-actions. The author is indebted to Prof. J. J. Stevenson, of New York, Prof. P. R. Uhler and John W. M. Lee, Esq., of Baltimore, and Lloyd P. Smith, Esq., of Philadelphia, for valuable assistance. OFFICE, ALLENTOWN IRON COMPANY, 230 SOUTH THIRD STREET, PHILADELPHIA, September 5th, 1881. ALABAMA. Geological Survey of Alabama. Report of Progress for 1879 and 1880, by Eugene A. Smith, State Geologist. Montgomery, 1881. 8vo., 158 pp., and 2 maps. CALIFORNIA. Omit Report of Hon. T. Butler King, in Supplement 1. For Trash's Geology and Industrial Resources, etc., in Supplement I., read Tyson's, etc: Fremont's Memoir on Upper California, is also published as XXXth Congress, 1st Session. Senate Mis. Doe., No 148, and has a map. For Randall's Report in Supplement I, read Report of the Special Committee in favor of a Geological Survey, submitted by Mr. Randall, April 24th, 1851. a.d., 1851. 8vo., 1.9 pp. XXXIst Congress, 1st Session, Sea. Ex. Doc., No. 47, Part 2 [Part 1 is Tyson's Report.] Report of the Secretary of War in further compliance with the Resolution of the Senate, calling for Copies of

Jan 1, 1881

By Earl Oliver

Dean Roscoe Pound, of Harvard Law School, in addressing the A.I.M.E. Petroleum Division on Feb. 22, 1934, said, "When you are able to work out a program that is mechanically feasible, that is economicaIly advisable, and which seems in your judgment, which is just as good as that of anyone, to be politically wise, you will not have very much trouble in the end in inducing the courts of today to find that it is legally sound." The purpose of this paper is to show: first, legal conditions necessary to promote conservation and stabilization; and second, to suggest operating procedure when those legal conditions are established. The proposal is mechanically feasible and economically advisable. A growing public understanding should make it politically wise. The disappointing progress in the development of conservation and stabilization can be attributed to the lack of two legal concepts as integral parts of oil and gas law; i.e., (1) a practical substitute for the capture rule, (2) collective ownership control for the individual oil and gas pool. When these two concepts are established on an equitable basis, conservation and stabilization procedure will become a comparatively simple process, more or less automatic in its adaptation and operation. Establishing these concepts is the function of the law-making agencies and might well be left to them for discussion except that the mechanical processes that give them form and substance must first be developed by the engineer. A Substitute for the Capture Rule Much has been written on these subjects, but the most concrete statement that has come to the attention of this writer is the following from an article by Charles G. Haglund in the Kentucky Law Journal of May, 1934: The Oxford1 case is not only authority for the proposition that it is competent for the legislature to modify the old property law of capture with respect to oil and gas but that it may also delegate such authority to a subordinate body.

Jan 1, 1935

By Edward Halse

The tin-deposits of Durango, Mexico, have been ably described by Mr. W. R. Ingalls in a paper published in our Transactions in 1895.* While the occurrellces of tin-ore in other parts of the Republic are similar in many resperts to those in Durango, there are noteworthy local differences which, it is hoped, ma? lend interest to the present paper. The deposits examined by me in May, 1895, are found in the Serrania de Chacuaco, Municipality of Sain Alto, District of Sombrerete. The workings are situated in a range of mountains having a general northwest to southeast trend between Sombrerete and Fresnillo; the most northerly claim (La Desparranlada) being about six leagues southeast of the former town. El Refugio lies about four leagues to the southwest, and El Calabrote eight leagues to the west, of Fresnillo. The claims are from about 8425 to 8775 feet above sea-level, and from 1500 to 1800 feet above Sain Alto, the position of which town is marked in the map printed in Mr. Ingalls's paper. In order to reach the claims, one uses the carriage-road from Sain Alto to the small tin-colony of Las Cuevas; from the latter place to the mines there is only a rough mule-track. The mountain range consists of a rugged, weathered, gray granite rock, remarkable for large grains of quartz, and is flanked by masses of rhyolite and rhyolite-tuff of upper Tertiary age. The whole formation is broken up by narrow and steep willding arroyos and deep barrancas, mainly the result of denudation, and it appears to be a southeasterlj extension of the tin-bearing belt of rocks north of Durango City. Here and

Jan 1, 1900

By F. F. Craig

Many full-scale waterflooding operations are preceded by pilot floods, one purpose of which is to provide an estimate of recoverable oil. A laboratory model study was made to determine the influence of the producing wells' effective productivity on the oil recovery efficiency of single five-spot pilots, as well as single injection well pilot floods. The effective productivity is indicated by the value of Condition Ratio, defined as the actual well productivity to that of on undamaged and non-stimulated, normal-sized well in the same formation. The effects of initial gas satrcration and mubility ratio on recovery eficiency were also investigated in this model study. Model test results skowed that at favorable mobiliry ratios, a five-spot pilot flood can provide a direct quantitative estimate of the recoverable oil in the pilot area. If the pilot producer's Candition Ratio is 2.2 or more, upwards of 90 per cent of the recoverable oil in the pilot area is recovered from the inside producer, regqrdless of the mobility ratio or initial gas saturation. This Condition Ratio can be achieved with preyent fracturing techniques. Model studies also showed that over the range of imposed injection pressure differences and regional pressure gradients normally encountered in field operations, there was no effect on the recovery efficiency of a five-spot pilot waterflood. Model studies of single injection well pilot waterfloods showed that with no initial gas saturation, the total oil recovery at the offset producing wells can indicate the oil recovery possible by full-scale waterflooding. It is essential that the Condition Ratios of the offset wells be above 1.4. If an initial gas saturation exists prior to water injection, the recoverable oil cannot be directly evaluated by a single injection well pilot flood. However, the production per formance of such a flood can be used to provide information on volumetric sweep efficiency. INTRODUCTION Oil reservoirs are conlplex structures and cannot always be fully studied in the laboratory. Therefore, many operators consider it prudent to evaluate a waterflood prospect by means of a pilot flood. Pilot waterfloods generally involve one of two well arrangements: a single five-spot pilot waterflood, involving four injectors and an internal pilot producing well; and a single injection well pilot flood (sometimes called an inverted five-spot pilot) having one injector and four sur- rounding pilot producers. Some pilot floods are composed of multiple five-spot pilot patterns. To yield information applicable to field-wide performance, the pilot must be located in a representative portion of the reservoir. Pilot floods generally are conducted for one or more of the following reasons: (1) to determine whether water could be injected at desirably high rates, (2) to determine whether an oil bank or zone of increased oil saturation is formed by water injection, and (3) to estimate the oil recovery by waterflooding. Many of the early pilot water-floods were conducted for only the first two reasons. As soon as a buzz in oil production was obtained in the pilot, water injection was initiated throughout the entire lease or field. A number ot laboratory studies have been directed toward determining conditions under which a pilot flood could yield a quantitative estimate of the oil recovery possible by full-scale pattern flooding. One of the early studies of single five-spot pilot flooding' showed that well damage to the inside pilot producer could reduce the total amount of oil recovered. In a study of the single injection well pilot flood pattern,' the results indicated that if the model boundaries were no closer than a half-well spacing beyond the pilot pattern, the pilot performance in the laboratory is unaffected by these boundaries. In another study,? he effect of initial gas saturation and mobility ratio on the ratio of production to injection rate for various groupings of five-spot patterns was defined by mathematical and analog methods. In a study4 involving both potentiometric and flow model experiments at a mobiliry ratio of unity, four different pilot patterns were studied. These included a single five-spot, a single injection well pilot, a cluster of four single injection well pilots and six inverted five-spots. In this study the ratio of well diameter to the distance between injection and producing wells was held constant at 1:1000. The effect of the 7 ratio-—the ratio of the pressure drawdown at the producing wells to the pressure build-up at the injection wells on the pilot performance-was studied. The values of 7 ratio ranged from 0 to 0.34. Results showed that both the total oil recovery and the total fluid production from the pilot relative to the cumulative injection increased with increasing values of the 7 ratio. The effect of both the ratio of injection to producing rates and mobility ratio on the oil recovery performance of a liquid-saturated single five-spot pilot flood was studied in a series of flow model tests.5 Rate ratios ranged from one to four, and mobility rates ranged from 0.1 to 10. Resulls of these tests showed that at low rate ratios, the pilot producers may recover up to four times the recover-

Jan 1, 1966

By J. S. Miller

This paper describes the method of mining a steeply pitching anthracite seam on a heavy pitch in the Orchard vein in No. 1 Tunnel of the Lehigh Coal and Navigation Co. The Orchard vein in the Neaquehoning district has a thickness of about 15 ft. on the level of the gangway, which is sufficient thickness for the gangway to be driven full width in coal. Above the gangway, the vein becomes thinner and near the surface is about 8 it. thick. The coal is of good hard quality and carries a fairly good roof. The pitch of the vein is between 65" and 70". Usually the breast-and-pillar method has been employed in the mining of the steeply pitching veins in this section. This method produced good results as far as the mining of the breast was concerned but the recovery of the pillar was difficult as to full extraction and expensive as regards costs. To recover these pillars after the breasts were driven, three methods were commonly employed; they were known as the pillar-breast method, pillar-skipping method, and pillar-chute method. The pillar-breast method consisted in putting a battery in one corner of the pillar (Fig. I), coupling the manways A and B of the two adjacent breasts for two or three lengths ahead of the working face of the pillar being cut, and working the pillar as a breast. This method was used by the more skilled miners of the earlier days but has practically been abandoned. A slight variation of this method is used to some extent. In this case, the pillars are left wider than ordinarily and of sufficient width for the full-width breast to be driven in and a small pillar left on each side of the pillar breast between it and the regular breasts. With the completion of the "pillar breast," the ribs are drilled full of holes, loaded, and fired. In the pillar-skipping method (Fig. 2), the middle breast of three is not driven through and is drawn empty while the outside and inside breasts are kept full. At the corners of the two pillars standing, batteries are put in and a skip of the two pillars started; the coal in the two pillars is blasted over into the empty breast. A small pillar is kept along the

Jan 1, 1925

By A. M. Starfield

The study of strain waves in rock over the past decade has, for the most part, been an investigation related, but not applied, to rock blasting; the design of rock blasts has proceeded on a basis that is independent of strain wave research. This duality is reflected in the paper by Dr. Clark.1 While the greater part of the paper is devoted to a discussion of spherical waves in elastic and visco-elastic media, it is in an entirely unrelated section, the section on scaling and cratering, that the practical approach to rock blasting is found. Work done by the U. S. Bureau of Mines, as described in the paper by Duvall, Atchison, and Fogelson,2 has established a correlation between crater dimensions and the peak compressive strain in the rock. Strain wave measurements have thus been used to compare explosives but have not, as yet, been applied to the planning of a production round once an explosive has been selected. The optimum burden, for instance, is still determined either by experience, empirical formulae (e.g. that of Langefors 3), or a cratering experiment and the theory that has been developed around that proposed by Livingston.4 Even then there is some ambiguity in applying deductions from short, concentrated explosive charges to the long charges often used in practice (although Bauer 5 reports doing this with considerable success) and wave theory has until recently thrown no light on this problem, being confined, with only a few exceptions, to spherical charges. The hesitation in applying strain wave theory has probably been due to two questions that have not been answered satisfactorily: just how important is the strain wave in rock breakage, and if it is important, under what conditions will the wave break rock? This paper is an attempt to answer the first question, to avoid the second question by an admittedly oversimplified assumption, and then to investigate the implications of this assumption for blasting with long cylindrical charges.

Jan 1, 1967

By Charles A. Ashburner

THE appliances which have been proposed, and the modifications in the construction of boiler-furnaces which have been made for the prevention of smoke, and the utilization of what are ordinarily called the waste products of combustion, have been innumerable.

Jan 1, 1882

By G. W. Healy

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

Jan 1, 1963

By Frank Firmstone

IN Chemical Phenomena of Iron Iron Smelting, Mr. Bell gives the weight of materials required to fill furnaces of various sizes at the Clarence Works ; as this differs very much from the weight required for furnaces at Glendon, where anthracite and in agnetic and brown iron-ores are used, a comparison is interesting. Taking furnaces at Glendon of 4800 and 11,900 cubic feet capacity and comparing them with the Clarence furnaces of 6000 cubic feet and 11,500 cubic feet, we find that the 4800 cubic feet at Glendon and the 6000 cubic feet at Clarence required respectively

By H. W. Paxton, G. M. Pound

A method is outlined for taking into account variation in chemical potential of both components in evaluating capillary effects at growing interfaces. The results are compared with experiment, and seem to be in reasonably good accord for Widman-statten ferrite growing in austenite. ENERY pointed out that during the steady-state growth of phases with a rather small radius of curvature at their advancing edge capillarity cannot be neglected. By proper application of the Laplace equation a correction must be made to the activity gradients down which diffusion occurs. Subsequent workers have concerned themselves with attempts to evaluate specific cases by the use and modification of the principles laid down by Zener.2-5 To solve the problem in its simplest form it is necessary to assume thermodynamic equilibrium at the interface and to select some criterion which will allocate the available free energy between reversible and irreversible processes. Zener chose to assume that the division should be made such that the new phase grew at the maximum rate. Other workers have used the same2,3 or different assumptions, e.g., maximum rate of free-energy dissipation,4 minimum rate of entropy production.5 Li6 has proposed that the "thermokinetic potential" should be a minimum at steady state. The purpose of this presentation is to note that most prior treatments have considered variations due to capillarity only in the chemical potential of the mobile constituent, and that a more consistent treatment must involve a consideration of the variation of chemical potentials of both solute -and sol- vent in a binary system.* As an example, the way in which this arises for ferrite growing from austenite may be illustrated by reference to Fig. l(a). The line OABC shows a typical variation of carbon activity with composition at one atmosphere pressure (at a transformation temperature below A3). In the tip of a growing ferrite plate with a hemi-cylindricab leading edge of radius ?, the pressure due to capillarity is*

Jan 1, 1963

By Jacques Friedel

Jan 1, 1964

Jan 1, 1880

By Alan Kissock

MOLYBDENUM is thought of as one of the rarer elements, for though it occurs in almost every country of the world it is seldom found in commercial quantities. In this country, however, there is one deposit which makes the term "rare" a misnomer. There are two commercially mined molybdenum minerals: molybdenite, the sulfide, and wulfenite, a lead molybdate. Of these two only the former is of any con- sequence but wulfenite is of mineralogical interest. It is frequently associated with oxidized lead ores and particularly in arid sections. Deposits, however, are usually quite superficial. It is highly oxidized and yet it does not appear to be an alteration product for it apparently disappears below water level and I know of no case where primary molybdenite, or in fact any molybdenum whatever has been identified below these surface wulfenite occurrences. The genesis of wulfenite would make an !- interesting study.

Jan 1, 1933

By Reuben B. Ellestad, Fremont F. Clarke

Lithium chemical plant extraction methods are discussed with reference to 1) base exchange with alkali sulphates; 2) processing based on roasting with lime; 3) miscellaneous methods; and 4) application of the Lithium Corp. process to extraction of lithium from run-of-mine, low grade spodumene ore, or concentrates. IN the early days of the lithium industry most of the production was from lepidolite, zinnwaldite, and amblygonite. Nearly all the early extraction processes described in the literature involve heating the finely ground mineral with sulphuric or hydrochloric acid. On subsequent water leaching most of the bases present in the mineral (especially aluminum) are dissolved as sulphates. As a result, the leach solution required extensive chemical purification before the lithium could be precipitated as carbonate. Following the remarkable growth of the lithium industry to its present size, zinnwaldite and amblygonite ores must be considered of minor importance only. Attention is now focused on spodumene, abundant enough in North America to be a major source of supply, and there are important supplies of lepidolite and petalite in Africa. The extraction processes described below all apply to spodumene, although several will also operate on other lithium minerals, such as petalite. Base Exchange with Alkali Sulphates: A distinct advance was made with the disclosures of Wadman and von Girsewalt. In these methods the finely ground silicate ore (spodumene or lepidolite) is intimately mixed with an excess of alkali sulphate (usually K2SO4) in at least a 1 to 1 proportion, and the mixture was heated to a relatively high temperature. Base exchange results, with the formation of lithium sulphate. A water leach dissolves the lithium sulphate, together with the excess potassium sulphate. Successful operation of this type of process requires very thorough grinding and mixing, as well as careful temperature control. The use of K2SO4 is objectionable from cost considerations since purification of lithium carbonate requires the use of potassium carbonate, if the K2SO4 is to be recovered and recycled. The lower solubility of K2SO4 as compared with Na2S04 is also objectionable, since it limits the concentration of the Li2SO4 solution to be precipitated by K2SO4. Early laboratory-scale investigation of this process by Lithium Corp. was not encouraging. Other related base exchange processes are those of Lindblad, Wallden, and Sivander3 and Sivander, Gard, Villestad, and Wallen4. The former covers the reaction of lithium silicate minerals with a sodium sulphate solution, at 100" to 300°C (under pressure), while the latter involves the extraction of silicate minerals with molten sodium sulphate. Both these processes would seem to be difficult and expensive to operate.

Jan 1, 1956

By J. D. MacKenzie

THE world production of copper for the first eight months of 1927 shows an increase of 3 per cent over the same period in 1926. Since February of this year, however, production has been considerably curtailed. The United States reduction in the last four months has been offset by the increased South Ameri-can and Belgian Congo production. The United States is now producing 58 per cent of the world production, Chile and Peru 17.3 per cent, Belgian Congo 5 per cent. In 1926 the United States produced 54 per cent, Chile and Peru 16.3 per cent, Belgian Congo 6.3 per cent. Production, Tons 1917-largest war year 1,580,000 1925 1,581,000 1926-increase 3 per cent 1,628,000 1927-increase 3 per cent 1,670,000 Copper Producing Countries, 8 mo., 1927: Tons Per Cent United States 644,000 58.0 Chile and Peru 192,000 17.3 Europe 90,000 8.1 Belgian Congo 56,000 5.0 Japan 46,000 4.1 Mexico 30,000 2.7 Canada 23,000 2.1 Figures are not available for Spain and Portugal, which would probably precede Mexico.

Jan 12, 1927

By Frederick Jr. Prime

THE first catalogue of Geological Reports of the United States was prepared by Prof. O. C. Marsh, and published in the American Journal of Science and Arts for 1867, vol. xliii, second series. Since then the list has more than doubled, and it was thought that the publication of a new catalogue, brought down to date, would be useful to many of the members of the Institute of Mining Engineers. The compiler will be most thankful to have any omissions or inaccuracies in the list sent to him, to be published as a supplement in the next volume of the Transactions. Especially to have the correct title, number of pages, plates, and maps of any volume on the list to which an * is prefixed, as he has been unable to personally consult such works. A preliminary list was issued last February, which has been almost doubled by the kindness of many friends. The writer desires more especially to express the obligations he is under to the following gentlemen The Chief of Engineers, U. S. A.; Principal Dawson, Mr. G. M. Dawson, Drs. B. J. Harrington and T. Sterry Hunt, of Montreal; Mr. H. Engelmann, of La Salle, Ill.; Dr. F. V. Hayden and Prof. J. W. Powell, U. S. Department of the Interior ; Prof. E. W. Hilgard, University of California; Prof. Henry Y. Hind, Windsor, N. S.; Prof. C. H. Hitchcock, of Dartmouth College; Mr. Henry A. Holmes, State Librarian, Albany; Maj. Jed. Hotchkiss, Staunton, Va. ; Prof. W. C. Kerr, Raleigh, N. C.; Dr. J. S. Newberry, of Columbia College ; Prof. W. H. Pettee, of the University of Michigan ; Dr. Samuel H. Scudder, Prof. N. S. Shaler, and Prof. J. D. Whitney, of Harvard College ; Mr. Sanderson Smith and Prof. J. J. Stevenson, of New York ; Mr. Addison Van Name, of Yale College, and Lieut. Geo. M. Wheeler, U. S. Engineers. PHILADELPHIA, 907 Walnut Street, October 1st, 1879.

Jan 1, 1879