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By C. P. Karr

For several years, the Bureau of Standards has been working in cooperation with an Advisory Committee on non-ferrous metals on various phases of the production and testing of zinc bronzes. The work has dealt especially with the type of metal known as "Admiralty bronze" in England and as "Government bronze" in this country and consisting of 88 copper, 10 tin, and 2 zinc. Several reports have been made on this subject and these should be considered in connection with this paper.' First Series of Five Foundry Tests A very brief summary of the first series of five foundry tests has been made12 but for the sake of clearness the results are given here in different form. The five foundries cooperating in this investigation were: Ohio Brass Co., Mansfield, Ohio; Titanium Alloy Mfg. Co., Niagara Falls, N. Y.; Packard Motor Car Co., Detroit, Mich.; National Cash Register Co., Dayton, Ohio; Bureau of Standards, Washington, D. C. The object of the work was to determine whether uniform results could be obtained with this alloy in different foundries working under definite instructions. One of the participating foundries prepared, from virgin metal, a stock of ingots of the composition 88 copper, 10 tin, 2 zinc, and at the same time poured nine test bars from this melt of virgin metal. The results of the physical tests of these bars are shown in Table 1. Examination of this table shows that the highest and most nearly uniform results were obtained when the virgin metal was cast flat in chill molds and the lowest and- most variable results were encountered when it was cast, vertical in green-sand molds. In this, as in all other tables, the mean deviation was obtained by the usual method of taking the average of the differences of the individual values from the average values.

Jan 1, 1921

By J. E. Hackford

In some research work carried out by the writer, certain results have been obtained which bear on the fundamental nature and origin of coal and the relationship between coal and petroleum. Without entering into a discussion of the details of the experiments, which were conducted on petroleum and derived bitumens, there are given here, by way of definition, some of the relations that the writer has established between certain classes of bitumens of petroliferous origin. Bitumen.—-A natural organic substance, gaseous, liquid, or solid, consisting of hydrocarbons and the oxy-or thionic derivatives of the same, or of a mixture of all three. Diaspha1tenes.—-Those portions of bitumens that are soluble in ether or carbon disulfide, but are insoluble in a mixture of equal parts of ether and alcohol. Diasphaltenes are produced by the oxidation or thionization of petroleum oils; they have, as the name indicates, twice the molecular weight of asphaltenes, into which they are converted when subjected to moderate temperature. For example, an artificially produced diasphaltene, which was readily soluble in pentane and ether, was quite insoluble in either of these solvents after heating for three weeks at a temperature of 100" C., and was converted into an insoluble asphaltene. Aspha1tenes.—Those portions of bitumen that are insoluble in ether or ether alcohol but are soluble in carbon disulfide. Aspha1tites.—Those solid or semisolid natural bitumens that are composed, for the most part, of asphaltenes or diasphaltenes. A pure asphaltitel would be composed wholly of asphaltenes and diasphaltenes, but most asphaltites contain small percentages of oil and wax, which have not yet been converted into asphaltenes; they may also contain A small percent.age of kerotenes, which represent the next stage of the metamorphosis of asphaltenes. Among the naturally occurring oxyasphaltites may be mentioned grahamite; and among the thioasphaltites, gilsonite.

Jan 1, 1921

By Mitchell, Edmund I.

VARIOUS suggestions as to proper fees for engineering services have been put forth by individual practitioners and by the American Institute of Consulting Engineers, the Connecticut Society of Civil Engineers, the Iowa Engineering Society and the Mahoning Valley (Ohio) Engineers, for the guidance of both the engineer and his client. The American Institute of Architects also has a schedule of minimum charges (revised 1908). So far as can be determined, however, the four national societies representing civil, mining, mechanical and electrical engineering have never given consideration to this question. An examination of technical periodicals published during the past decade shows that these schedules make provision for three methods of charging; i.e., (A) a percentage of the cost of the completed project; (B) a per diem rate; and (C) a fixed sum. Suggested minimum charges are as follows:

Jan 1, 1921

By D. Harrington, B. W. Dyer

"One of the products of the activities of the United States Chemical Warfare Service is a simple device and method for nearly instantaneous determination of small quantities of carbon monoxide in air. Since the war, this device has been diverted to commercial uses, and is now being marketed in connection with rapid determination of the comparatively small but dangerous quantities of CO, which may be found in garages, in sewers, about blast furnaces, etc. Also, it probably has a definite field of use in both coal and metal mines in connection with fires and explosions, as well as in confined places after firing of explosives) the latter applica-tion being of especial importance in metal mining.The device as marketed is readily portable, being small and light enough to carry in a coat pocket of medium size. In operation, a sample of the air mixture is drawn into a small rubber bulb, then forced through a small glass tube filled with certain chemicals upon which CO has the effect of changing the original color from gray or white to shades of green, the deepness of the green determining the percentage of CO in the air. A color scale is attached for purpose of comparison and determination of CO percentage. Only a few minutes are consumed in obtaining the result, all work being done on the ground.The exact effect of minute quantities (up to 1/10 of 1 percent) of CO on the human system is somewhat uncertain, and much research has been and is being done to obtain definite data on this point. It is, however, definitely known that in air containing more than 1/10 of 1 percent CO men doing hard work are quickly and seriously affected. As the gas is tasteless, colorless and odorless, methods of determining the presence of both small and large quantities have been of much importance. Technical Paper 11 of the U. S. Bureau of Mines gives much data as to effect of CO on mice and canaries. It was found that mice show very little distress until the CO content is about 0.20 percent, but quickly succumb when that percentage is exceeded; canaries are somewhat more susceptible; they quickly show distress in as little as 0.15 percent 00, and soon collapse when that percentage is exceeded."

Jan 1, 1921

By Parley Potter

GENTLEMEN OF THE COAL MINTING INSTITUTE: I was requested to write an article on mining a short time ago; however, the time has been so short that I have not had time to prepare an article as I would like to have presented it to this body. In writing this article it has not been my intention in making comparison of various mines, to favor one or discredit the other. I hope it will be considered in that light. The coal mining industry as I have seen it in the past, at present and in the future. In years gone by large tracts of coal land could be obtained at a very small cost, and as yet coal land may be purchased at a reasonable price in this country, but I believe the time is near at hand when the methods of mining will have to be changed greatly in this country. Many changes have taken place-in the last few years, some of them have been forced by law, others by the coal operators themselves, after being convinced that the changes made were for their own benefit. During my 20 years in the mines I have seen thousands and thousands of tons of coal lost that could have been saved if proper methods of mining had been used. The Room and Pillar system of mining coal is none. too good at its best ; a certain per cent of the coal is always lost, yet it is about the only system that can be used under certain conditions, but where the Longwall system can be used I believe it is the best system yet introduced. If the Longwall system is used' there is no coal lost. You get it all as you advance with the workings. Some coal operators object to the Longwall system for several reasons, and most of the reasons they advance are not founded on facts. For instance some of them claim it is too expensive. I will admit that the cost per ton is a little higher in Longwall than it is in Room and Pillar as a rule for the amount of coal' mined, but after the Room and Pillar mine is finished as a rule there are thousands of tons of good coal lost, for the simple reason that it cannot be mined at a profit. In many cases if the same mine had been operated on the Longwall system every ton of saleable coal could have been mined at a fair profit, and in the long run would have netted the owner much more money than it did under the Room and Pillar system. The Longwall system has been in operation many years in Europe and especially Great Britain, and is the most approved of systems in many countries at the present time. Millions of tons of coal have been saved by its use in those countries. It is claimed that the Armour Packing Company loses nothing but the squeal of the hog when it is killed, and doesn't allow it to squeal much. Why lose coal if the Longwall system of mining will save it? The Longwall mine is far more easy to ventilate than the Room and Pillar mine; the air has a much less distance to travel for the same amount of working face in Longwall than it has in the Room and Pillar.

Jan 1, 1921

By Geo. Otis Smith

Twelve years ago, the Director of the United States Geological Survey addressed to the Secretary of the Interior a letter calling attention to the government's need for liquid fuel for naval use and pointing out that the rate of increase in demand was more rapid than the increase in production.' This letter, in a way, inaugurated the policy of public oil-land withdrawals, which was well founded in its primary purpose of protecting the oil industry and highly desirable in its immediate effect of checking the over-development of that day in California. Unfortunately, however, through delays in legislation, this policy may be regarded now as having outlived both its intent and its usefulness. In 1908, the country's production of oil was 178,500,000 bbl., and there was a surplus above consumption of more than 20,000,000 bbl. available to go into storage. In 1918, 10 years later, the oil wells of the United States yielded 356,000,000 bb1.—nearly twice the yield of 1908—but to meet the demands of the increased consumption more than 24,000,000 bbl. had to be drawn from storage. Nor is this all of the brief comparison. In 1918, our excess of imports over exports of crude petroleum was nearly 33,000,000 bbl. whereas in 1908 we exported 3,500,000 bbl., which was net, as we had not begun to import Mexican oil. In this period, the annual fuel-oil consumption of the railroads alone has increased from 16,871,000 to 36,714,000 bbl.; the annual gasoline production from 540,000,000 gal. to 3,500,000,000 gal. This record may be taken not only as justifying the earlier appeal for Federal action, but as warranting deliberate attention to the oil problem of today. Need of Future Supply The position of the United States in regard to oil can best be characterized as precarious. Using more than one-third of a billion barrels a year, we are drawing not only from the underground pools but also from storage, and both of these supplies are limited. In 1918, the contribu-

Jan 1, 1921

By A. B. Young

In the original design of the flue system, the flues from the roasters delivered their gases to a large brick dust chamber which discharged into another flue with stack connection, as shown in Fig. 1. The treater is so situated that the gases are taken by it directly from the chamber and discharged again into the flue. The complete installation comprises two treater units, only one of which has been installed at present. The treater is essentially a flue 1.0 ft. high, 12 ft. wide, and 61 ft. long. (3 by 3.6 by 18.5 m.). Suspended inside, vertically and running lengthwise, are four banks of No. 20 corrugated iron plates; each bank is 10 ft. long, making an effective treater length of 40 ft. The spacing from center to center of the rows of plat,es is 9 1/8 in. (23 cm.) giving six-

Jan 1, 1921

ATTENTION has recently been directed to the subject of dust production and methods of allaying same in the Broken Hill mines, so that the time would seem opportune for the local branch of the Institute to discuss certain features of an important phase of the health question in connection with underground work. Tests conducted in the Broken Hill South mine and at other mines at Broken Hill have shown that the ordinary operatioils of mining, such as boring, blasting, and shovelling, may be accompanied by the production of considerable dust unless water is judiciously used.In South Africa·dust particles under 5 microns size are regarded as dangerous, becailse they are so small as to be invisible to the naked eye, and wm esc'ape the protections set up by nature in the nose and throat, and thus may be inhaled in large quantity. A micron is 1 25000th part of an inch. This paper contains an account of the work done on the Broken Hill South mine chiefly, though some tests were done on other local mines.An acknowledgment is due to Mr. T. A. Reid, of the Broken Hill South mine, who conducted some of the tests herein mentioned, and under whose supervision most dust counts were made. Numerous dust samples have been taken by means of thekonimeter, an instrument designed by Dr. Kotze, the Government mining engineer of the Union of South Africa, and fully described...

Jan 1, 1921

Bosworth, T. 0. The Mackenzie oilfield of northern Canada. Petroleum Times, vol. 5, Apr. 30, 1921, pp. 489-491. Jour. Inst. Petroleum Technologists, vol. 7, Oct., 1921, pp. 276-290; discussion, pp. 290-297. Gives location of the field, some of its geology, mode of occurrence and character of the oil. See also Oil Trade Jour., vol. 12, June, 1921, pp. 48-108. Canadian Min. Jour., vol. 42, May 27, 1921, pp. 420-422. Oil and Gas Jour., vol. 20, June 3, 1921, pp. 90-90. Petroleum World (London), vol. 18, June, 1921, pp. 233-2.64, 236-238, 240-241. Bull. Canadian Inst. min. and met., July, 1921, pp. 629-638. Mining and Metallurgy, Oct., 1921, pp. 47-48. Bureau of Foreign and Domestic Commerce. Resources of Balkan and Near Eastern countries. Commerce Repts., Oct. 24, 1921, pp. 488-489. Includes summary of the mineral resources of these countries, mentioning petroleum and allied substances in Roumania, Albania, Anatolia, Mesopotamia, Palestine, Arabia, Persia.

Jan 1, 1921

By N. A. C. Smith

The Bureau of Mines motor gasoline surveys have been conducted in January and July, during 1920 and 1921. The Bureau has obtained and analyzed samples of gasoline representative of that marketed in the larger cities. These surveys have indicated that the gasoline on the market during the winter months is more volatile than that sold during the summer months. Naturally, the motorist desires a more volatile gasoline in the cold winter months, as it affords greater ease in starting. The fourth semi-annual motor gasoline survey, conducted during the month of July, shows an interesting relation between the market price and the quality of motor gasoline. This is particularly evident if figures obtained today are compared with those of a year ago. At the time the Bureau of Mines conducted its summer survey of motor gasoline last year, the average tank wagon price of gasoline was 28.2 cents per gallon. This year it was 21.2 cents, a drop of practically 25%.

Jan 1, 1921

By R. H. Johnson

All strata not yielding oil or gas in commereial quantities or a corresponding amount of water may be called dry in a wide sense. In petroleum geology, however, we may exclude all sands of too low or fine porosity to yield gaseous or fluid contents to the hole drilled in the sand before any original pressure that its contents may be under is disturbed. Most rocks are of this class and they are not reservoirs in our definition; their "dryness" is wholly a matter of course. What are the contents of the pores or what is the exact porosity of such rocks is of almost no concern to us, for economically they are "dry." What does interest us is the content of a rock having sufficient porosity and the pores of sufficient size to yield oil or gas in commercial quantities, if they were present under original pressure. Dryness of these reservoirs is a matter of supreme practical importance. Three views current as to such dryness seem, to me, to apply in a few cases only. It is the purpose of this paper to give reasons for this position and for believing that, in ordinary sedimentary rocks, there is only rarely a reservoir of competent porosity and undisturbed pressure that is dry in the sense of not yielding water, oil, or gas when first penetrated. 1. Gardnerl writes of some Kentucky sands, "There has never been present any salt water or other water in the sand." Absence of water cannot demonstrate this position. It is necessary to show that the rocks were not laid down in water, but in air, and that they became so enclosed, while still above the water-table of the ground water, that water has not been able to enter since. Most of these sands, and certainly the productive limestones, were deposited in water; and such sands as have been commercially productive show no reason for believing that the overlying shale or limestone was not laid down progressively from one direction and in water that would have flooded it. NO adequate explanation has been offered for this hypothesis, which is so inherently improbable. 2, Reeves2 urges that "sands originally water filled may have been drained of their water and not filled when later covered." It is difficult I James H. Gardner: Kentucky as an Oil State. Science, N. S. (1917) 46, 279-280. Reeves: Origin of the Natural Brines of Oil Fields. Johns Hopkins Univ. Circ., N. S. (1917) N. 3; Absence of Water in Certain Sandstones of the Appalachian Field. Econ. Geol. (1917) la, 354-378.

Jan 1, 1921

By W. H. Herschel, E. W. Dean

"IntroductoryThe common practice of the petroleum industry is to measure viscosity by the use of instruments of the efflux or capillary tube type. The Saybolt universal viscosimeter has been tentatively adopted as a standard by the American Society for Testing Materials and is used extensively in the United States.Several instruments of foreign origin are also more or less familiar, such as the Redwood, the Engier, and the Baroey.Effina-type viscosimeters are well adapted to the ordinary needs of petroleum testing laberatories as they are simple and rugged in construction and away to manipulate, even in the hands of operators lacking scientific training. They have, however, certain limitations and for certain spacial types of work there are notable advantages incident to the use of the so-called torsion types of type of viacosimeter. The most satisfactory type of torsion viscosimeter now available in the market some to be that of MacMchael, which has been discussed in detail in a recent paper (Herschel, W. H., The MacMichael Torsional Viscosimeter. Jour. of Int. and Eng. Chem., vol. 12, 1920, pp. 282-286). The present paper indicates conditions under which this viscosimeter may be used to advantage in the petroleum laboratory, and outlines simple methods of operation and calibration."

Jan 1, 1921

By D. A. Stout

The Rouse Mine, belonging to the Colorado Fuel & Iron Company, earlier known as the Santa Clara Mine, is located at Rouse, Huerfano County, Colorado. Operations at this property started about the year 1899, after the old Rouse mine had been drowned out by a large flow of water coming from the strata underlying the Cameron seam. The present new Rouse mine was opened by a slope on what is familiarly known as the Walsen seam in the Walsenburg district. This slope has an average grade of 12 per cent bearing approximately, south 45 degrees west, and having at the present time a total length of 6300 feet. This seam has an average thickness at that property of five and one-half feet; however, there are sections of the mine where the thickness is from seven to eight feet. The mine has been developed. since the time it was opened on what is known as the Room and Pillar system ; water level entries have been driven right and left off the slope, and in some cases the rooms are driven directly up the pitch; and in other cases entries have been driven with rooms turned on water level courses. The first flow of water of which we have ally record was encountered in 1901 in what was called the "Second West Entry." This flow, however, was small, and did not require the installation of any large pump unit. From 1901 up until 1909 the flow increased normally as the field was developed. In January, 1909, the first large inflow occurred, coming from a break in the seventh west entry, making a total flow at that time of about 500 gallons per minute. This necessitated putting in larger pumps, and the first pump to be installed of the centrifugal type was a 600 gallon Worthington. By the year 1911 the water had increased, due to additional development, until it was found necessary to install an additional 600 gallon Worthington centrifugal type pump. In December, 1912, a break occurred in the eighth west entry, between the fourth and sixth cross entries, making 2000 gallons per minute. This flow decreased after a period of three weeks some 500 gallons, but on account of the quantity of water then being handled at the mine, and in view of the fact that we needed some reserve pumping equipment to take care of these flows, and additional 600-gallon Worthington centrifugal type pump was installed in June, 1913. An the latter part of 1914 a 250 gallon Reese roturbo was installed to take care of the water, which was being made in the lower workings of the slope. We found after the installation of the centrifugal pumps that the water decreased to a certain degree in the uppermost workings. This led us to believe that the field was being drained, more or less, and the head reduced ; however, our ideas in regard to this were again upset in December, 1915, when we encountered a flow in room 6 off the first cross entry on the ninth east entry. This flow was not as large as previous flows had been, but made 200 gallons per minute.

Jan 1, 1921

By Frederic P. Dewey

It is common to blame irregular assay results upon volatilization and much has been written upon the subject, but there is no real evidence that, in a properly conducted assay, the loss of either gold or silver by volatilization is sufficient to affect appreciably the result, even when arsenic or antimony may be present. Bulk assays of flue dust from assay muffles have been published, but the data given are totally insufficient to even approximate the volatilization from a single assay; and such figures as we have indicate the volatilization to be extremely small. Diligent search in the literature and wide inquiry among assayers and instructors have failed to produce a single case where the litharge volatilized in making an assay has been collected and assayed for gold and silver. Having attempted to do this, with most indifferent success, I am not surprised that this has not been done. While various textbooks give volatilization as a cause of loss in cupella-tion, it may safely be said that in the rare cases where this volatilization is sufficient to affect appreciably the result it is due to excessive temperature. Percy' says "The loss of silver by volatilization during cupellation is very slight (unless the temperature has been much too high), and may be disregarded." This statement is repeated by the Beringers2 and Smith,3 who includes gold with silver. Mitchell4 says the litharge fume rarely contains over one ten-thousandth of silver. Campredon5 ays that at a proper temperature no silver is lost by volatilization. Primarily, excessive temperature may be due to too high general temperature in the muffle; but it may often be due to temperature localized within the bead by oxidation of the metals and this may be influenced by other causes than the general temperature. I have shown an ex-

Jan 1, 1921

TUNGSTEN occupies an outstanding position amongst metals to-day, for by its use modern manufacturing methods have received a wonderful impetus. The important part played by tungsten in the recent war is not generally recognized. It was tungsten steel, in the shape of highspeed tools, that kept our soldiers supplied with munitions of war at more than one critical period. Tungsten added the necessary hardness and durability to various metals which were indispensable for carrying the war to a successful conclusion. In the words of...

Jan 1, 1921

By Van H. Manning

In substance, the international aspects of the petroleum industry, as these relate to the United States, are as follows: The domestic production is not keeping pace with the domestic demands; our best engineering talent warns us of the imminence of a decreased production by our oil wells, although more oil is needed; and the only practical source whence this increasing demand can be supplied for some time to come will be the foreign fields. Other nations have given thought to the future and, in recent years, have shown a tendency to adopt strong nationalistic policies regarding their petroleum resources, policies that hinder or prevent the exploitation of these resources by other nationals. In consequence, we find that, facing a probable shortage of the domestic supply, our nationals are excluded from foreign fields; and this in spite of the fact that foreign nationals have been permitted to enter into and exploit our own oil resources on an equality with American citizens and without hindrance or restrictions. This country has supplied the larger part of the petroleum consumed by the world and yet, with a failing supply imminent, it finds that those countries that, have been drawing upon our resources to supply their needs are showing a tendency to exclude us from their resources. In this way we shall be transferred from a position of dominence to one of dependence; and only by sufferance of those countries that are now seeking financial or political control of petroleum supplies, shall we be able to obtain the oil we will need. Impoetance of Petroleum Petroleum has become, during recent years, one of the essentials of our social and industrial life. All civilized countries recognize that the world is dependent on petroleum as on nothing else except textiles: foodstuffs, coal, and iron. Today, the tendency is toward an ever-increasing consumption of petroleum and its products as new and more efficient uses are found for them. The utilization of petroleum is extending more and more into the structure of our civilization. Consequently,

Jan 1, 1921

UNLIKE coal mines, in which some form of artificial ventilation is rendered necessary by gases given off by the material mined and is also enforced by the mining laws of all countries, metalliferous mines have almost entirely relied on natural ventilation, viz., that due to the difference in temperature between the outside atmosphere and the mine air. In small mines natural ventilation has proved sufficient, but as mining proceeds at a greater depth, and where large ore bodies arebeing attacked the writer is of opinion that some means of artificial ventilation will be rendered necessary if only from an economic standpoint.The Broken Hill Proprietary Mine was one of the first metal mines to introduce a scheme of artificial ventilation on a large scale. In order to render the working conditions of the semi-friable stopes of Block 12 and the lower levels of Block 11 morecomfortable for the men at work in these places, in 1903 it was decided to install a fan to thoroughly ventilate these stopes. The fan chosen was a Capell double-inlet fan beltdriven from a steam engine: this engine was later on replacedby an electric motor. The fan was put in commission at the latter end of 1904; its principal dimensions are as follows: Length 6 ft. 6 in., diam. 7 ft., diam. of inlet 4 ft. 7i in. The fan is reversible, though this is a rather misleading term, asthe direction in which the fan blades revolve is not reversed...

Jan 1, 1921

By M. J. Gavin

Within the past three years numerous inquiries for information on oil shale have been received by the Bureau of Manes. These inquiries have been increasing to such an extent that it has seemed advisable to issue a short paper prior to the publication of a bulletin on the subject, giving a, general discussion of the subject and a comprehensive list of references, so that those interested in the details of obtaining oil from shale can find additional information without much difficulty. Some of those who desire information are interested only in a general discussion of the subject, or are not in a position to refer to books and' articles describing the industry. The material for this paper is largely derived from published information on oil shale. Much of the information is obtained-from the books and articles mentioned in the list of references, and has been compiled with the intent of furnishing information to those not interested in all the details.

Jan 1, 1921

By W. B. Vietz, C. W. Hill, T. P. Thomas

FLUXES, in general, may be classified according to their use as soldering, foundry or casting, and metallurgical and the chemistry of their action follows quite closely this division. The term foundry or casting fluxes, as used here, refers to the substances added to molten metals, preparatory to casting into molds or ingots, with the object of removing small amounts of impurities that have been introduced in handling or melting the metal, which was placed in a fair state of purity by the previous refining or metallurgical processes. The sources of these impurities are the oxide coating on the surface of the ingots, material extracted or mechanically removed from the crucible or furnace wall, and those formed by the reaction of the molten metal with the heating gases or furnace atmosphere. As commonly used, the term fluxes is applied to such materials as ammonium chloride, zinc chloride, salt, borax, and boric oxide. A second class of materials, usually called deoxidizers, includes substances such as metallic phosphides, sub-oxides, carbides, and bo-rides, that reduce the metallic oxides present in the metal. A third class includes various compounds that arc molten and non-volatile at the temperature of the molten metal and are used primarily to protect the surface of the metal from the action of the furnace or exterior atmosphere; to this class belong such mixtures as lime and fluorspar, lime and soda ash, various minerals, etc. In some cases these protective layers may act in a manner similar to the metallurgical fluxes and dissolve or unite with the oxide impurities of the metal, but as generally employed this latter action is negligible since there is little opportunity for the coverings to come into contact with more than the surface of the metal, and hence they arc without action on the body of the molten mass. The use of fluxes is the result of factory experience and tradition, but an extensive study has not been made of the chemical and physical actions that occur or the effects of these actions on the properties of the metal. It would seem necessary in any successful study of metal fluxes to determine not only what impurities are present in metals melted under

Jan 1, 1921

By Howard Eavenson

THE eleven mines of the United States Coal and Coke Co. in the Pocahontas coal field are situated in McDowell County, W. Va., which is a mountainous region. The valleys rarely exceed 200 ft. (60 m.) is width, the hill sides slope from 25° to 33°, and the tops, from 600, to 900 ft. above the valleys, carry practically no level land. At least 80 per cent. of the area is covered with timber. All the workings are drift mines; and while the average grades of the seams worked are ample for drainage, local dips and swamps necessitate, the use of a large number of local pumps or of numerous drainage ditches to keep the mine free from water during heavy rains. The water handled in any mine is not great, compared with the coal output, and usually causes little trouble except during extremely wet periods. In hew workings, the water encountered, except in rare cases, is trifling; it is only after rib drawing has started and the surface has been broken that water troubles begin. The strata overlying the coal are sandstone, shales, and slates; as the soil is thin and sandy, it does not tend to puddle and stop the cracks, which remain open for a long time. As mining progresses and the robbed area increases, the broken area becomes larger, increasing the openings into the mined territory. The cover over the robbed portions of the mines varies from 30 to 750 ft. (9 to 228 m.). When the ground is saturated, considerable water finds its way into the mines the day after a heavy rainfall and for three or four days it tends to fill the low places, wash the tracks, etc. and. unless from three to four times as many pumps are installed as are normally needed, considerable', output is lost. In most cases the water will .flow from the mines, so the obvious solution is to provide drainage .ditches of ample size to carry the maximum flow expected, so that the inflow will have no opportunity to flood the working places.

Jan 1, 1921