Search Documents

By H. S. Greismer

Alabama washes a larger percentage of its total coal output than any state in the Union. For producing coking coal, three-compartment jigs are favored; mines providing, steam and commercial coal use single-compartment jigs exclusively. Chemists are as necessary to washing plants as recording gages are to power plants. Experiments in Alabama indicate that the sludge released by coal-washing plants can be deposited in streams and on agricultural lands without disastrous results. CAMPBELL, 1 in 1896 said: "The Birmingham district in Alabama has certain great advantages for there are few places in the world where fuel and ore are so near together, although, unfortunately, both are of inferior quality; the ore being low in iron and high in phosphorus and the coal giving a weak and impure coke." This statement could not have been, questioned in 1894, but by 1896 several Robinson-Ramsay washers had been put into operation and weak and impure coke was a thing of the past. The Warrior coal field of Alabama contains six seams that yield coking coal of excellent quality. In descending- order, they are Brookwood, Milldale, Pratt, America, Mary Lee, and Black Creek. In each of these, however, bands of rock and bone coal of varying thickness are stratified with the coal; and while some of these impurities can be separated from the coal by the miner, much of it must be loaded out with the coal: Consequently, unless the coal is washed before being coked, it will yield a coke of varying ash and sulfur content quite unsatisfactory, for blast-furnace use. At present, the Gulf States Steel Co. is producing run-of-mine coal at its Virginia mine, from the America seam, that is uniformly low enough in ash to permit of coking without washing, but this is the only exception to the above statement. Alabama was the first state to experiment seriously with coal washers, was the first to install washers on a large scale and, up to the present, has maintained the lead. The Alabama State Mine Inspector reports that during 1923 20,919,303 tons of bituminous coal were mined in Alabama; 12,858,499 tons of which were delivered to coal washers for treatment.

Jan 9, 1924

Jan 1, 1946

By Dennis K. Mortensen

Startup of the 9000 tpd Sacaton concentrator is expected to increase Asarco's domestic copper concentrate capacity by 21%. The plant site is located due west of the mining operations, consisting of both crushing and concentrating facilities. Arthur G. McKee & Co. served as the prime contractor for the project. The Sacaton mineralization contains both sulfide and oxide ores. Primary mineral constituents are chalcocite, azurite, malachite, chrysocolla, and minor amounts of silver and occasional gold. Sulfides are distinguished from oxides when more than half the total copper content is in the form of a sulfide copper mineral. While non-sulfide copper minerals are considerably less prevalent throughout the orebody, they tend to occur quite intimately with the sulfide minerals, particularly in the upper zones of the mineralization. For this reason the decision was made to treat all the ore in a flotation circuit using existing sulfidizing methods.

Jan 11, 1974

By V. H. Wilhelm

The year 1936 was a prosperous one for the oil industry in California. Increases in crude prices were posted in February and March. Re-establishment of voluntary curtailment in February was a factor in holding production at an efficient level throughout the year. Reduction of storage was effected through adherence to curtailment measures, aided by greater demand and smaller average well completions. During the first six years of voluntary curtailment, allotments were increased during the summer season and reduced during the winter season. This year, good results were obtained through a revised system of allocation, by which the California monthly quota was held constant at approximately 540,000 bbl. per day. After a 7-month period of practically unrestricted production (ending in January 1936), numerous operators found that curtailment was still necessary, as California and export market,s were not yet capable of absorbing the state's potential production, which was estimated to be in the neighborhood of 850,000 bbl. per day. Therefore, in February California operators again placed themselves under voluntary curtailment; with the result that state production dropped from around 700,000 bbl. per day in January to a low of 565,000 bbl. per day in April, and increased gradually to around 585,000 bbl. per day for December. Drilling activity during the year increased about 10 per cent over that of the preceding year, although the resultant production per well decreased. Field Discoveries As a result of a very active wildcatting campaign in California, aided by better interpretation of geophysical data, five new oil fields and two new gas fields were discovered. Oil Fields Greeley Field, Kern County.—The Standard Oil Co. added to its list of djscoveries by drilling and completing its K.C.L. No. 11-1 well at a

Jan 1, 1937

By Ralph W. Bailey, William B. Price

ARSENIC, antimony and phosphorus are now used in the brass industry as standard inhibitors in preventing dezincification in [ ] condenser tubes. This subject has been thoroughly covered by Barry,1 who described the testing procedure by total immersion of suitable specimens in a I per cent cupric chloride solution at definite temperatures. Effects of dezincification were then determined by loss in tensile strength and elongation of the test specimens after definite periods of immersion. In the crystallography of the chemical elements as tabulated by William Hume-Rothery,2 phosphorus (metallic), arsenic, antimony and bismuth are placed in group V-B and the type of crystal lattice for arsenic, antimony and bismuth is given as rhombohedral. The Metals Handbook3 [ ] lists them as "rhombohedral hexagonal," with the additional notation that for arsenic this is the ordinary form at 20°C.; other modifications known or probable at other temperatures. In view of these statements and of the fact that phosphorus, arsenic and antimony are effective in increasing the resistance to dezincification, it was natural to assume that bismuth would act in the same manner. A series of tests was therefore carried out employing the methods described by Barry. Much to our surprise, bismuth did not inhibit dezincification, but rather seemed to accelerate it. Tensile-test speci-

Jan 1, 1942

By A. B., Sabin

THERE are many who know The Lucky Tiger and will remember the 35-mile road from Esqueda, a station on The Nacozari Railroad in northern Sonora, Mexico. They will remember the box canyons of the Agua Caliente Mountains which are scarcely wide enough for two cars to pass; the Bavispe River which one hour may be a lazy trickle and the next a sweeping torrent, and the tortuous road up Tigre and Espuela canyons, now following the wash, now hugging some gigantic red cliff. It is still the same. From camp the view of the distant blue-gray mountains is the same. But one thing a visitor of a former day might miss: The hundreds of pack mules and burros, loaded with concentrates from the mill, which used to take most of the road and show up at the most inopportune places, have almost disappeared, replaced of course by the auto truck.

Jan 1, 1929

By Alfred Beasley

LEAD-REFINING practice at the. Bunker Hill differs to some extent from that of other United States refineries using the Parkes process, in that the Bunker Hill-has reverted to a custom used years ago of making two kinds of skims, or crusts, in the desilverizing kettles. Also, this was the first refinery to adopt the liquation process for silver skims as developed in Australia. Both of these ideas were brought to the attention of the operator by H. S. J. Sommerset, in the summer of 1924, while he was visiting metallurgical plants in the United States, when he was general superintendent of the Broken Hill Associated Smelters Pty., Ltd., of Port Pirie, South Australia. Since Mr. Sommerset's visit, United States patents on the liquation process have been issued to George Kenneth Williams, of Port Pirie, South Australia. At the Bunker Hill, the lead bullion is conveyed from the blast furnaces to the refinery in brick-lined cast-steel pots, each having a capacity of 5 tons, by a 20-ton electric crane, to which is suspended a Fairbanks-Morse suspension-type scale on which the gross, tare and net weights are obtained. The bullion is poured from the small bullion pots into either one of two kettles of 105 tons capacity, and when a kettle is entirely filled the heavy dross is removed by skimming it into a 5-ton pot suspended by the crane. The crane operator becomes proficient in the manipulation and a kettle is skimmed in a very short time. After the kettle is skimmed clean the bullion is pumped to a kettle of the same size alongside, where the bullion is cooled until it has almost frozen. By using two kettles for the drossing operation, one to accumulate the bullion where the heavy dross is removed, and then pumping to a clean kettle comparatively free of hangings, etc., it is possible to reduce the copper content much lower than if only one kettle is used in the operation. The average yearly analysis of bullion is given in Table 1.

Jan 1, 1930

E. W. Parker, Washington, D. C.: In connection with Mr. Blauvelt's paper, a brief sketch of the development of by-product coke-making in the United States may prove of interest. The first radical departure from the prevalent beehive oven to the by-product retort oven was inaugurated in 1891 by the Solvay Process Company, at Syracuse, N. Y. In that year was begun the construction of 12 Semet-Solvay ovens, which were completed in 1893. During 1893 these ovens produced 12,850 tons of coke, an average.of a little over 1000 tons each. In the following year the production amounted to 16,500 tons, not quite 1400 tons per oven. These 12 ovens were in reality an experiment, the success of which was attested by the addition to the same plant of 13 more ovens, begun in 1895 and completed in 1896. They were followed by the construction in 1896 of 25 ovens of the same type at Sharon, Pa., and 50 more at Dunbar, Pa. These 100 ovens represented the total number of Semet-Solvay ovens completed and in operation up to the close of 1897. The construction of 180 more, however—120 at Ensley, Ala., and 60 at Benwood, near Wheeling, W. Va.—was begun in 1897. The plant for the latter is laid out for double the number stated. The 60 ovens begun in 1897 have now been completed. An initial plant of Otto-Hoffman ovens was built at Johnstown, Pa., in 1895, and began making coke in 1896. One hundred and twenty additional ovens of this type were begun in 1896 and completed in 1897 at Glassport, near McKeesport, Pa. During the present year 100 Otto-Hoffman ovens are being added to the plant at Johnstown, and 400 of the same type are in course of construction at Everett, near Boston, Mass. The plant at the latter place is laid out for a total of 1200 ovens.

Jan 1, 1899

By Chas. H. Behre, Arbiter. Nathaniel

Two outstanding factors characterize most undertakings in the mineral industries: (1) mineral deposits are not equally distributed over the earth but are localized by natural processes, and (2) the mineral industries are largely based upon wasting assets. Neither of these factors is invariably true, for a few mineral materials, such as water, are essentially world-wide and others are replaced periodically by processes not unlike crop production. Indeed, with some, such as the salts in the sea, the supply is cyclic in short or long periods, whereas others, like water, though locally or periodically in short supply, are essentially inexhaustible. But to the extent that most minerals are limited to certain areas and are "permanently" consumed, any industry founded upon them, by implication, demands great care in planning for the most effective extraction-the essence of wise and conservative expenditure. Several less unusual yet also truly fundamental factors in the economics of the mineral industry are those involving (1) the various kinds and properties of mineral materials, which influence their use; (2) their geo- logic and geographic availability; and (3) the techniques unique to their discovery, exploration, and utilization. This chapter is designed primarily as a brief background for later ones and as a summary of the several un- usual or at least special factors and of their effect upon the economics of the mineral industry. The social and political and especially the economic aspects of the industry are the main subjects of this volume and are dealt with in extended fashion in subsequent chapters. Fundamental Characteristics of Mineral Deposits DEFINITIONS Minerals are naturally occurring compounds of nonliving matter, each technically defined as having (1) a chemical composition that may vary

Jan 1, 1959

By E. P. Mathewson

(Butte Meeting, August, 1913.) IN a discussion -of a paper on " The Basic Process as Applied to Copper Smelting," by Percy C. Gilchrist, read before the Society of Chemical Industry, London, Jan. 5, 1S91,1 Prof. W. C. Roberts Austen asked Mr. Gilchrist whether he thought that the substitution of a basic lining for acid lining in the Marshes process would afford anything like the service which it had been shown to render in the metallurgy, of iron. Claude Vautin stated that he had experimented for over two years with basic linings for Bessemer converters for copper mattes at Cobar, but had given up the attempt on the score of cost. Mr. Gilchrist in his reply stated that he did not believe in applying any system of Bessemerizing to copper. About the time of the presentation of the paper mentioned, Herman Keller, Superintendent of the Parrott smelter, in Butte, was experimenting on a large scale with converters lined with magnesite brick. He gave up the idea on account of the cost of linings and because no particular advantage was observed. My belief is that his tuyeres and converters were -too small. A short time; afterward similar experiments were tried at the Great Falls plant of the Boston & Montana Co., said at the Old Works of the Anaconda Copper Mining Co. in Anaconda. These were abandoned on the score of cost and the lack of advantages. The same cause of failure, in my opinion, holds here. The Anaconda Copper Mining Co., however, adopted the magnesite brick lining for its tilting casting machines.

Jan 6, 1913

By Nicholas J. Grant, Ernest P. Abrahamson

IN recent work, Bloom and Grant' and Stein and IGrant' have indicated that a high temperature chromium phase exists. In the 68 pct Cr-Ni binary they found a eutectoid reaction, P chromium transforming to a chromium plus y nickel at 1215°C. Un-

Jan 1, 1957

By N. F. Dyson, T. R. Scott

The iilzfluence of catalytic agents on the oxidation of ZnS has been studied under pressure leaching conditions, using a chemically prepared sample of ZnS which was substantially unreactive on heating at 113°C with dilute sulfuric acid and 250 psi oxygen. Nurnerous prospective catalysts were added at the ratio of 0.024 mole per mole ZnS in the above reaction but pvonounced catalytic activity was confined to copper, bismuth, rutheniuwl, molybdenum, and iron in order of. decreasing effectiveness. In the absence of acid, where sulfate was the sole product of oxidation, catalysis was exhibited by copper and ruthenium only. Parameters affecting the oxidation rate were catalyst concentration, temperature, time, oxygen pressure, and a7riount of acid, the first two being most important. The main product of oxidation in the acid reaction was sulfur, with trinor amounts of sulfate. An electrochemical (galvanic) mechanism has been suggested for the sulfuv-forming reaction, whereby the relatively inert ZnS is "activated" by incorporation of catalyst ions in the lattice and the same catalysts subsequently accelerate the reduction of dissolved oxygen at cathodic sites on the ZnS surface. Insufficient data was obtained to Provide a detailed mechanism for sulfate fornzation, which is favored at low acidities and probably proceeds th'rough intermediate transient species not identified in the preseni work. THE oxidation of zinc sulfide at elevated temperatures and pressures takes place according to the following simplified reactions: ZnS + io2 + H2SO4 — ZnSO4 + SG + HsO [i] ZnS + 20,-ZSO [21 In dilute acid both reactions occur but Reaction [I] is usually predominant, whereas in the absence of acid only Reaction [2] can be observed. Both proceed very slowly with chemically pure zinc sulfide but can be greatly accelerated by the addition of suitable catalysts, as suggested by jorling' in 1954. Nevertheless, an initial success in the pressure leaching of zinc concentrates was achieved by Forward and veltman2 without any deliberate addition of catalytic agents and it was only later that the catalytic role of iron, present in concentrates both as (ZnFe)S and as impurities, was recognized and eventually patented.3 It is now apparent that another catalyst, uiz., copper, may have also played a part in the successful extraction of zinc, since copper sulfate is almost universally used as an activator in the flotation of sphalerite and can be adsorbed on the mineral surface in sufficient amount The importance of catalysis in oxidation-reduction reactions such as those cited above has been emphasized by various writers and Halpern4 sums up the situation when he writes that "there is good reason to believe that such ions (e.g., Cu) may exert an important catalytic influence on the various homogeneous and heterogeneous reactions which occur during leaching, particularly of sulfides, thus affecting not only the leaching rates but also the nature of the final products." Nevertheless relatively little work has appeared on this topic, one of the main reasons being that sufficiently pure samples of sulfide minerals are difficult to prepare or obtain. When it is realized that 1 part Cu in 2000 parts of ZnS is sufficient to exert a pronounced catalytic effect, the magnitude of the purity problem is evident. An incentive to undertake the present work was that an adequate supply of "pure" zinc sulfide became available. When preliminary tests established that the material, despite its large surface area, was substantially unreactive under pressure leaching conditions, the inference was made that it was sufficiently free from catalytic impurities to be suitable for studies in which known amounts of potential catalytic agents could be added. The first objective in the following work was to identify those ions or compounds which accelerate the reaction rate and, for practical reasons, to determine the effects of parameters such as amgunt of catalyst, temperature, time, acid concentration, and oxygen pressure. The second and ultimately the more important objective was to make use of the experimental results to further our knowledge of the reaction mechanisms occurring under pressure leaching conditions. The fact that catalysts can dramatically increase the reaction rate suggests that physical factors such as absorption of gaseous oxygen, transport of reactants and products, and so forth, are not of major importance under the experimental conditions employed and an opportunity is thereby provided to concentrate on the heterogeneous reaction on the surface of the sulfide particles. As will appear in the sequel, the first of these objectives has been achieved in a semiquantitative fashion but a great deal still remains to be clarified in the field of reaction mechanisms. EXPERIMENTAL a) Materials. The white zinc sulfide used was a chemically prepared "Laboratory Reagent" material (B.D.H.) and X-ray diffraction tests showed it to contain both sphalerite and wurtzite. The specific surface area, measured by argon absorption at 77"K, varied between 3.9 and 4.6 sq m per g. Analysis gave 65.0 pct Zn (67.1 pct theory) and 31.9 pct S (32.9 pct theory). Other metallic sulfides (CdS, FeS, and so forth) used in the experiments were also chemical preparations of "Laboratory Reagent" grade. Samples of mar ma-

Jan 1, 1969

By B. E. Eakin, R. T. Ellington

An apparatus and a procedure for determining the viscosity behavior of hydrocarbons at pressures up to 10,000 psia and temperatures between 77 and 400° F are described. The equipment is suitable for measuring viscosity of either the liquid or vapor phases or the fluid above the two-phase envelope for systems exhihiting retrograde phenomena, according no the phase state of the system within these ranges of temperature and pressure. Equations are developed for calculation of viscosity from the experimental measurements, and new data for the viscosities of ethane and propane at 77° F are reported. INTRODUCTION With the advent of higher pressures and temperatures in industrial processes and deep petroleum and natural gas reservoirs, demand has increased for accurate values of physical properties of hydrocarbons under these conditions. Proportionately, more frequent occurrence of natural gas and condensate-type fluids is encountered as fluid hydrocarbons are discovered at greater depths. This increases the importance, to the reservoir engineer, of being able to predict accurately the physical properties of light hydrocarbon systems in the dense-gas and light-liquid phase states. Reliable gas viscosity data are limited primarily to measurements made on pure components near ambient temperature and at low pressures. Few investigations have been reported for high pressures, and except for methane, data on light hydrocarbons are subject to question. This is demonstrated by the large discrepancy between sets of data on the same component reported by different investigators. For mixtures in the dense gas and light liquid regions and for fluids exhibiting retrograde behavior there are very few published experimental data. Viscosity data for methane have been reported by Bicher and Katz,1 Sage and Lacey,12 Comings, et al,3 Golubev,3 and Carr,3 with good agreement among the last three sets of data. Comings, Golubev and Carr utilized capillary tube instruments for which the theory of fluid flow is well established. The theory permits calculation of the viscosity directly from the experi- mental data and dimensions of the instrument alone. Sage and Lacey, and Bicher and Katz used rolling-ball viscometers. The theory of the rolling-ball viscometer has not been completely established, and these instruments presently require calibration by use of fluids of known viscosity behavior before viscosities of test fluids can be measured. To obtain accurate data it is necessary that the rolling-ball viscometers be calibrated by use of fluids of density and viscosity similar to the test fluids, a difficult selection for the gas phase. From the methane data and experimental tests on various natural gases, Carr developed a correlation for predicting the PVT behavior of light natural gases.2,3,4 This correlation was based on data for a very limited composition range; its application to rich gases and condensate fluids is questionable. The object of this investigation is to develop an instrument which can be used to obtain viscosity data at reservoir temperatures and pressures, for rich gases, condensate-type systems above the two-phase envelope and light liquid mixtures. These data will be used in an effort to develop correlations to represent the viscosity behavior of these fluids. APPARATUS In a previous viscosity study Carr2 utilized a modified Rankine capillary viscometer configuration," Fig. 1. In this instrument the gas to be tested is forced through the capillary tube in laminar flow by motion of a mercury pellet in the fall tube, the measured displacement time being that required for the mercury slug to move between the brass timer rings. The viscometer is constructed of glass and mounted in a steel pressure vessel. The test gas pressure in the viscometer is balanced by an inert gas (usually nitrogen) in the vessel. Excellent results have been obtained with instruments of this type, with Carr2 and Comings5 reporting repro-ducibilities of 99.5 to 99.3 per cent and an estimated absolute accuracy of 99 per cent. However, these instruments have limitations which have precluded their use for liquids. The need for maintaining a balance between pressures of the test fluid and inert gas in the viscometer vessel presents operating problems, and requires charging the test fluid to the viscometer very slowly. The principle drawback to the Rankine unit is behavior of the mercury slug which provides the pressure differential across the capillary. When even trace quantities of propane or heavier hydrocarbons are present in the test gas, the mercury tends to subdivide

By Fred W. Gordon

Apart from the character of pig-iron to be manufactured, other than that it shall be well reduced and open-grained, the selection of the materials should be such as to produce it at the lowest cost. As a rule, the sources of fuels and limestones are not so extensively varied as those of the ores. Many Eastern furnaces are now using Lake Superior ores, and but recently a part of the supply came from foreign ports. It is, however, of the highest importance that the character of fuels and limestones, as well as ores, should be carefully considered in determining their value and making judicious selection among those available. The formulas here offered are based upon the assumption that the heat-requirements for a given mixture are measured by a constant required by the oxide of iron, added to that required for a unit of slag, multiplied by the weight of that slag per unit of iron. The heat-requirements for oxide of iron per unit of pig-iron made are assumed to be 2854 centigrade units. This is taken from the careful analysis of Sir Lowthian Bell, and, so far as the writer is able to determine, is very nearly correct. Dividing this by the quantity of heat that may be evolved and utilized within the furnace per unit of carbon, determines the quantity of carbon required per unit of pigiron ; and if to this be added the quantity of carbon absorbed by the pig-iron, the total requirements in carbon are determined, on the assumption that pure oxide of iron is reduced with pure carbon by the ordinary process of the blast-furnace. Calculating the quantity of slag that would be made from a given mixture of ores, smelted with a given impure fuel and fluxed with a given impure limestone, multiplying this weight of slag by the heat-requirements of its unit (taken at 1050 C. H. U.), and dividing the product by the heat-units evolved and utilized within the furnace per unit of carbon, will determine the quantity of carbon required per unit of pig-iron for the slag.

Jan 1, 1893

By Eugene Stephenson

CRITICAL analyses of the work expended in producing oil by the utilization of gas energy have appeared in the publications of Shaw,1 Pierce and Lewis,2 and Herold,3 authors who have ably discussed the factors which must be taken into consideration in comparing energy consumed per barrel in various wells which are flowed by means of gas-lift. However, two distinct phases of oil production are concerned with the ratio of gas energy consumed to oil produced. One of these phases is the gas-lift, which utilizes the differential gas pressures for the purpose of flowing oil, whether these pressures be natural reservoir pressures or be induced by artificial compression of gas or air. The other phase has to do with prorating oil production in pools which are operated either as units, or are subject to such restrictions as those imposed at Oklahoma City by the Corporation Commission, or, by similar controlling groups in other fields. An abundance of literature is available relative to the problems of flowing wells by gas-lift, but the first suggestion that the energy of the gas within the oil and gas pool might serve as a basis for proration, appeared in the timely article by McWilliams.4 Much of the. dissatisfaction with proration in certain fields is because some operators feel that besides the hazard to the wells which accompanies the test, the method of allocating production on the basis of the "potential" gage is inequitable and gives some operators a distinct advantage over others.5 The most severe penalty may be exacted from the most progressive operators or those who attempt to produce their oil with a minimum quantity of reservoir gas. If :no difficulties ever

Jan 1, 1931

By P. H. Royster

On the Continent, ferromanganese has been produced in the blast furnace almost continuously since 1876, but little definite information concerning the practice is to be found in technical literature, and almost nothing in the way of a theory of the manganese furnace. In this country, prior to 1904, but one company had attempted its production in a serious way, and none of the operating data or other information from this company has been, or is, available to the public..In the last 5 years, as a result of the restriction of imports, a number of furnaces have been blown in on this alloy, with the result that in 1918 as many as 18 furnaces were in blast. The majority of the men in charge of these furnaces had had little previous experience in such operations; so the Bureau of Mines, in the summer of 1918, undertook the collection of data from ferromanganese furnaces. Operating data were collected by the Bureau from eleven ferromangahese furnaces, which will be referred to throughout this paper as furnaces A, B, C, F, G, I, J, K, L, M, and P; the dimensions of seven of the furnaces are given in Table 1. The companies from whom this information was obtained, and to whom should go the credit for whatever value this information may possess, are the Bethlehem Steel CO.,

Jan 1, 1920

Jan 1, 1942

By V. W. Bihlman, H. M. Williams

In the construction of internal-combustion engines, the cooling of the combustion chamber and pistons is of great importance. In certain types of engines, the adequate dissipation of heat from the bearings is also important. One of the important factors affecting heat dissipation from these parts is the thermal conductivity of the material used. A search of the technical literature shows that, in general, the thermal conductivity of the elements1 has been determined accurately by a number of investigators. The data on the industrial alloys are, however, meager. For an investigation of these alloys, the thermal-conductivity apparatus described in this paper has been constructed at the laboratory of the General Motors Research Corporation. It is desirable that an apparatus for work of this nature should give fair accuracy of results with a convenient form of specimen and a reasonable rapidity of operation. A summary of the different methods of determining thermal conductivity is given in the first volume of the " Dictionary of Applied Physics," pages 429 and 470. The method selected as best satisfying these conditions is that of Griffith, on page 443, with the addition of a guard ring similar in principle to the method used by Berget (P. 445). Briefly, the method consists of heating one end of a bar T, Fig. 1, electrically, measuring the amount of heat transmitted through the bar by a flow calorimeter J fastened to the other end, and measuring the temperature gradient along the bar. To compensate for the loss of heat laterally, the test bar is surrounded by a guard ring E, in the form of a steel pipe, which is electrically heated at the bottom and cooled at the top with a

Jan 1, 1923

[ ]

Jan 1, 1938

By Chas. A. Ashburner

The occurrence of oil- and gas-springs in the State of New York has been a fact of historical record since 1627, when the existence of the Cuba oil-spring was first recorded. The utilization of natural gas at Fredonia in 1821 attracted the attention of the public to the possibility of obtaining an illuminating gas by digging and drilling into the rocks. No active search was made, however, for oil or gas by the drilling of wells until after the discovery of commercial oil in Pennsylvania in 1859. In 1862 a well was drilled at Bradford, McKean County, Pennsylvania, but a few miles south of the New York state line, to the depth of 200 feet, in search of the oil-sand which had been found at Titusville, Oil City, and at other points in Western Pennsylvania. Immediately subsequent to this, other wells were drilled in search

Jan 1, 1888