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By Marcel R. Daly

In a preceding paper1 the writer has pointed out some apparent relationship between the distribution, on the surface of the globe,, of the known hydrocarbon deposits and the disposition of the principal zones of deformation of the earth's body (geosynclines). He wishes to present some further remarks on this subject. Petroleum deposits, or their derivatives or descendants, are found through the whole range of sedimentary strata, from the pre-Cambrian to the Quaternary. For instance, the prc-Beltian (Shuswap) series of the Canadian Cordillera are interbedded with limestones which are sometimes rich in carbonaceous matter (Sicamous limcstone); and the Beltian system of the same region contains layers of argillitcs and dolomitic limestones which are equally high in carbon content.2 This carbon may be interpreted as the last remnant of hydrocarbons previously contained in the rocks. On the other hand, the actual formation of hydrocarbons under conditions that would eventually permit their deposition in modern sediments is conceded by some geologists.3 Between these two extreme limits, bitumens are found indifferently in all sedimentaries. Thcy constitute a continuous series, some kind of a large family, whose individual members may be entitled to a community of origin and probably represent the different stages of evolution of the primitive, parent matter. The kinship between petroleum and such substances as asphalt, ozocerite, manjak, grahamite, albertite, etc., is well known; and E. H. Cunning-gam-Craig has recently shown how intimately shale fields and oil fields are connectcd.4 For this reason, no distinction is made in the present

Jan 1, 1918

By Eldon N. Dunlap

Recently the producing branch of the petroleum industry has shown a considerable and growing interest in the quantitative determination of the water, oil, and gas content of cores as it relates to estimation of reserves, to providing a basis for judging as to the feasibility of applying various secondary-recovery and pressure-maintenance processes, and in general to the operation of producing properties. For years it has been known that oil, gas and water coexisted in the pores of many semidepleted oil measures. It is now generally believed that oil-bearing beds contain connate water in amounts varying up to 50 per cent of the pore space. However, only lately has reliable direct evidence of the extensive occurrence of connate water in oil sands been published. Very little work has been done to ascertain the effect of this water on the productivity and ultimate recovery of oil from wells. It was the intent of this research to study the influence of interstitial water on the flow of oil through unconsolidated sands, with the hope that the results could be applied qualitatively to the flow of oil in underground reservoirs partly saturated with water. Obviously, ultimate recovery estimates based on the void volume of the reservoir will be in error unless a correction is made for the volume of water that occupies a portion of the effective pore volume of the reservoir. Evaluation engineers in the past have applied arbitrary saturation and recovery factors that may inadverently have compensated for the failure to consider specifically the water content. Nevertheless, the evidence available indicates that these factors need revising if each is to be independently correct and truly representative. Although the fact that the connate water renders part of the pore volume of the reservoir incapable of containing oil is of primary importance to the operator, it is also to his interest to know to what extent the presence of varying amounts of interstitial water influences the permeability of the sand to oil.

Jan 1, 1938

By W. H. Emmons

A DIATREME is a hole blown through a rock by gases, presumably of volcanic origin. Not all pipes of ore have formed by deposition of metals in such openings, but a con-siderable number have so formed. In this paper are described peculiar vein patterns that are believed to be incipient diatremes or "perforation pipes." Grading into this group is one showing thorough brecciation without rotation of fragments and into the latter a group of ore pipes showing brecciation with rotation of fragments-many of them with well rounded fragments. Also, volcanic craters or volcanic necks are explosion pipes. These may carry ore deposits along their contacts and some carry deposits within the pipes. As new data appear this group becomes increasingly impressive. It has been shown that veins are concentrated in and about cupolas of batholiths and that such veins commonly lienearly parallel to the long axes of cupolas as these are shown on plans. It would be supposed that conical cupolas would have radial patterns, but few vein systems exhibit radial patterns. It is probable that explo-sion pipes also may form in areas above conical cupolas. From these the gases escape more violently because the loads above them are less than above an elongated cupola where larger bodies of rock are affected. The hypothesis is sound mechanically, for the top of an elongated cupola is a line whereas the top of a conical cupola is a point.

Jan 1, 1938

By George Gardner

THE application of wet cleaning processes for the beneficiation of bituminous coal has created in some localities a problem in the recovery and disposal of fine solids in the washery water. The maximum allowable concentration of these solids in the washery circuit that is consistent with satisfactory operation of the cleaning units remains a controversial point. It has, however, been generally recognized for a number of years that some degree of control should be exerted over the concentration of such material. Early methods of control involved intermittent or continuous dis-charge of a portion of the plant slurry into near-by streams or settling ponds, and this persisted even after the adoption of settling tanks or cones. The practice is not always economical, for two reasons: first, because of the waste of coal, and, second, because it is sometimes difficult and expensive to obtain an adequate supply of water. The latter condi-tion often is aggravated by chemical treatment of the make-up water that is necessary to prevent excessive corrosion of plant equipment. The modern approach to this problem has been the adoption of continuous thickening devices. However, because such equipment occupies consid-erable plant space and is somewhat expensive to construct, the practice of loading these thickeners beyond their rated capacity is widespread, there-fore often the performance of such units is not altogether satisfactory. In recent years, European washeries have increased the rate of settling of the fine coal from the slurry by the addition of specially pre-pared starch solutions. These reagents cause flocculation of the solid particles and thereby increase the rate of sedimentation.

Jan 1, 1939

By Dorsey A. Lyon, Robert M. Keeney

The electric furnace has always been found to be especially adapted to melting, refining, and finishing processes throughout its gradual acceptance by metallurgists as a practical apparatus for conducting metallurgical operations. In the steel industry, the electric furnace is firmly established in the manufacture of steel of the highest grade, equal to crucible steel. For the production of the cheaper grades of steel in large tonnage, the electric furnace gives a higher-grade product than the open-hearth or converter, but due to the high cost of power prevailing in steel centers, considered from the electric furnace standpoint, it is not economical to produce tonnage steel in the electric furnace. As a refining and finishing agent for open-hearth or Bessemer steel, the electric furnace has had some degree of success in thc production of tonnage steel. After a study of the use of the electric furnace in the steel industry, it appears that there may be a possibility of its use to advantage for the melting of cathode copper. In the case of copper the problem is not one of actual refining, because the copper if refined properly by the electrolytic method needs no further refining; it needs simply to be cast into a marketable shape. The name "refining" is applied to the present finishing process, because in the operation oxygen and other impurities arc removed, which the electrolytic copper absorbs in being melted in the reverberatory furnace. Considering that processes may be positive, negative, and neutral, the electrolytic method would be positive; reverberatory melting of cathode copper, negative; and electric furnace melting, neutral. The electrolytic method produces about as pure a copper as is possible, if operated properly and the anodes are not too impure. The final reverberatory melting of this cathode copper lowers the grade of the final product, due to the absorption of gases and impurities. The reverberatory melting of cathode copper is one of the weak parts

Jan 1, 1915

By Harry Warren

THE Geology Department of the. University of British Columbia has undertaken the task of examining the ores from as many as possible of the gold mines of British Columbia. The object of this work is two-fold. First, it is known that detailed mineralographic studies are useful in attacking ore-dressing problems, and these studies are intended to be helpful to mill operators. Second, it is hoped that mineralogical and mineralographical studies will prove useful adjuncts to those of lithology and structure in throwing more light on problems related to the origin of the deposits. The paper shows that gold, for all practical purposes, is not present in an ore mineral in solid solution nor as a eutectic with any mineral; if the latter were true the gold particles would be distributed equally throughout that mineral. The gold occurs either as native gold or as a gold-silver telluride and is not distributed regularly through any mineral or minerals: The relationship between the gold or gold-bearing telluride and the associated minerals affords a means of classification that is not only simple but also appears to be directly related to the geological nature of the deposit, which may be summarized as follows: 1. Disseminated Gold Type. ;-Precious minerals in extremely small grains, which are distributed without regard to grain size, fractures or grain boundaries: (1) Hedley variety-gold in native form; (2) Surf Point variety-gold predominantly as telluride. 2. Veining Gold Type.-Precious minerals in grains of various sizes, which occur mainly along fractures and grain boundaries: (1) Cariboo gold quartz-gold in native form. (2) Waneta variety-gold as telluride.

Jan 1, 1937

By John C. Calhoun, Raymond G. Loper

Theoretical calculations for the decline of pressure and the variation of instantaneous producing gas-oil ratio with increased cumulative production have been made for reservoir systems under various producing drawdown values and for various spacings. These variables have been included by a modification of previously Published techniques. This consists essentially of utilizing a radial system flowing gas and oil in a succession of steady state calculations. The results of the calculations do not show any variation in the predicted behavior of the internal gas drive reservoir when either the drawdown or the spacing are changed. The prediction of performance on an internal gas drive reservoir has been presented by various authors. ',"' These predictions are in the form of a pressure decline and an instantaneous producing gas-oil ratio as a function of cumulative oil withdrawal. In making these predictions a basic assumption has been that the saturation of the reservoir is uniform throughout at any time, or that the pressure differential imposed on the reservoir system is zero. Because of these assumptions the validity of such predictions has been questioned. Their application to actual systems, where saturations are not uniform and where producing differentials exist, has been a hazardous procedure. The authors cited have used different methods of approach to the derivation of equations for making their predictions and for arriving at a solution of both equations, but basically the same relationships are utilized in each case. In all instances the instantaneous producing gas-oil ratio is calculated from the equation: In utilizing this equation an average reservoir pressure and an average reservoir saturation must be known, the former to define ß, v, s, and uo/ug and the latter to define kg/ko. Predictions can be made, therefore, only for the conditions of a uniform reservoir saturation and a uniform reservoir pressure. This restriction of requiring a uniform oil saturation can be resolved by applying two-phase steady state flow for the radial system to the reservoir's history. Radial steady state flow is defined when the ratio of phases flowing,

Jan 1, 1949

By C. L. Horn

All the tunneling machines discussed in this chapter are Calweld machines. I have divided the machines designed for soft-to-medium formations into three groups, correlated with typical formations and estimated compressive strengths: 1) Running sand and silt requiring blade cutters. 2) Chalk and clay, requiring drag-type cutters, for compressive strengths ranging from 0 to 2000 psi. 3) Sandstones, hard clays, and limestones, requiring disk cutters, for compressive strengths ranging from 2000 to 20,000 psi. All of the soft-to-medium-formation machines are powered by electric hydraulic or diesel hydraulic pumps. The pumps in turn drive hydraulic motors for the torque reaction. The soft-to-medium-formation machines are enclosed in a 360º shield with a cutting shoe, a center portion of the shield housing the mechanical equipment, and a tail shield. Tunnel supports are usually required, and the supports are normally erected in the tail shield. Our first machine was built in 1963, and all but five of the machines illustrated in the figures with this chapter were built in 1966 and 1967. Some of the machines manufactured will be discussed in the following sections; specific features as development has progressed will be pointed out. HARD-ROCK MACHINE The Calweld hard-rock machine has been designed along basic and accepted principles for a hard-rock mechanical borer. The features of this machine are as follows: 1) Direct electric motor drive through a planetary gear reduction ring and pinion gear, and then to the cutting head through a hollow drive shaft.

Jan 1, 1970

By W. O. Hotchkiss

DURING the summer of 1927, the Department of Terrestrial Magnetism of the Carnegie Institution of Washington joined with the Michigan College of Mining and Technology in conducting a series of earth-resistivity measurements in the Michigan copper country. The geological structure in this section is quite varied and fairly well known. The purpose of the investigation was to discover the correlation between the variations in electrical resistivity of large masses of soil and rock in place and the geological structure below the surface. The work done may be roughly divided into two parts: (1) Measurement and study of the variations in resistivity with depth, or with volume, to establish such general relations as exist between the two: and (2) the determination of the specific resistivity of various formations in order to make available more fundamental data which may aid in the interpretation of the results of the former type of measurement. A report by Mr. Rooney, which gives in detail the measurements made and the results obtained, forms the basis for this article. MEASUREMENT AND STUDY OF VARIATIONS IN RESISTIVITY The possibility of applying data from measurements of the physical properties of earth material to the 'study of the geological structure has long been recognized, and a number of methods for determining the position and character of concealed rock strata by means of seismic, gravitation, magnetic and electrical measurements made on the surface are being used with varying degrees of success. One physical property which varies widely for different materials, and hence affords an opportunity for distinguishing between them, is their electrical resistance. Locations were selected where the geological structures were well known and where the depths to the water level and bed rock had been determined by drilling. The problem was to determine the value of measurements of resistivity and its variations as indications of the geological structure below the surface.

Jan 1, 1928

By George Burgess

1. Introduction.-THE methods of production of sound steel ingots have been described in several papers read recently before this Institute. It was thought by Director Stratton, of the U. S. Bureau of Standards, and ourselves to be of sufficient interest and importance, as a further contribution to this subject, to compare the properties of rails rolled in one mill according to American practice, from several types of ingot of substantially the same chemical composition but cast by several processes; and to compare in considerable detail the properties of an ingot manufactured by the Hadfield special-feeding process and one of the usual type for rolling into rails. We are greatly indebted to F. W. Wood, President of the Maryland Steel Co., who made this investigation possible by kindly placing his rail mill at our disposal; and he and his associates at Sparrows Point did everything possible to make the experiment a success, including the execution of several of the tests and analyses. 2. Classification and Manufacture of Ingots.-Of the ingots used in this investigation, eight were made in Sheffield and furnished by Sir Robert Hadfield, and one was made and furnished by an American steel company,' as a comparison ingot, and was supposed to represent the usual type of ingot from which rails are made.

Jan 2, 1915

By Donald W. Barnett

U.S. environmentalists have tended to oppose all new energy developments. Their efforts may be counterproductive because opposition to, say, offshore oil directly leads to the continued use of other energy sources that may have a higher social cost. Rather than attempting to eliminate all pollution from energy production, which would be prohibitively expensive, one should minimize the social cost of energy production for the given demand. Linear programming is used to rank various oils (California State and O.C.S., Gulf of Alaska, Prudhoe Bay, Athabasca tar sands, oil shale and certain foreign crudes) in terms of their social desirability. The objective is to minimize the cost of supplying the California market, subject to resource, sulphur and oil spill constraints. Social desirability is indicated by the inclusion of the oil in the optimal solution and the size of the associated shadow price. the larger the shadow price, the greater the benefits of increased production. The more negative, the greater the cost associated with forcing consumption of that fuel. The environmental shadow prices indicate the size of the trade-off between a particular environmental standard and minimum cost. The trade-offs can be surprisingly large. any reasonable spill standard can be achieved by changing the development pattern. Generally, the further offshore, the smaller is the environmental degradation, but the more expensive is the oil. Foreign oils can be economically and environmentally inferior to domestic oils. Crude from the California O.C.S., San Joaquin Valley end Prudhoe Bay appears a valuable resource, while the Gulf of Alaska, synthetic and foreign crudes appear marginal to submarginal.

Jan 1, 1977

By Frank H. Probert

The mining laws relating to winding-ropes in some of the German provinces are very strict, and severe tests have to be periodically made to see that the ropes in use come up to the prescribed standard. A few notes on the method of testing the ropes and the results obtained may be of interest to the members of the Institute. Permission must be given by the Inspector of Mines to put up a winding-plant; and previous to installation a full report made by the manager, clearly setting forth all details of the shaft, the pit-head, engines and appliances appertaining thereto has to be sent to the mining officials. Accompanying each subsequent report, further details, such as the name of the firm supplying the rope, construction, quality of steel, date of installment, weight per meter, length, particulars of the safetycatches, cages, etc., must be given. At least one spare rope must be kept at ever? shaft ready for use in case of emergency. The rope must hang in the shaft, with cage attached, not less than twenty-four hours before it is used for winding; and it must have undergone a severe test in the manner hereafter described. The laws prescribe that when a rope is continually in use it must be tested every three months; but if the rope is only used every few days it must be tested at least every six months, in the presence of the superior officer; and notification of the date of testing has to be sent to the Bergrath two days before the test is made, in order that he can personally superintend the operation if he chooses. Should winding have been stopped for a long time, it is not necessary to test every six months; but before the rope can be used again it must be tested.

Jan 1, 1901

By H. G. Botset

ANY information that will increase the accuracy of our knowledge of the conditions prevailing in petroleum reservoirs should be of direct value in the determination of the proper operating technique as well as in the estimation of reserves and of ultimate production. The obvious method of obtaining this information is by studying a sample of the reservoir rock and its contents. In any such study, the problem of primary importance and maximum difficulty is that of getting the core to the surface in such a manner that its original fluid content is undis-turbed, which has so far proved to be an impossible task. Though it might be rash to say this will never be done, it is certainly safe to assume that a method for the recovery of a core at the surface in its undisturbed original state may not be developed in the immediate future, and certainly will not be forthcoming without a great deal of costly experimentation. Therefore any information that may be obtained that will help to correlate the state of a core (its fluid saturation) at the surface with its condition at the time it was drilled should be of value to the petroleum industry. The experiments described in this paper were undertaken with the purpose of determining, if possible, any relationship that might exist between the saturation of a core at the surface and its original fluid content. No consideration has been given to the question of contamina-tion by penetration of drilling water, since this problem has been exten-sively studied by other investigators. 1-3 Furthermore, it was regarded as being outside the scope of the present experiments, which were con-cerned only with the effect of pressure reduction upon the liquid content of cores. In an experimental study of this sort involving a large number of variables, accurate control of all factors is very important. The essen-tial and obvious procedure is to vary systematically one factor or condi-tion while keeping all the others constant, which necessarily involves a rather protracted and sometimes tedious experimental program.

Jan 1, 1939

By F. E. Bash

A GREAT many industrial operations require the application of heat to carry on or complete processes, in which cases the temperatures must often be controlled within very narrow limits. For the lower temperatures, this control is not, as a rule, difficult as a number of types of reliable pyrometers are available for the work; for example, the mercury and resistance thermometers and the thermocouple. For temperatures above a red heat, thermocouples, platinum resistance thermometers, and total radiation and optical pyrometers may be used, depending on conditions. It is often undesirable, and sometimes impossible, to take temperatures of material by immersing the pyrometer in it or by placing the temperature-measuring device in a position in which it will attain the temperature of the material. The pyrometer may contaminate the product; the temperature may be so high that the pyrometer will not hold its calibration, clue to ineffectual protection and consequent contamination; the object may be inaccessible, as a lamp filament, etc. In such cases, a total radiation or optical pyrometer must be used. The disappearing-filament, or Morse, type of optical pyrometer works on the following principle: An objective lens, Fig. 1, focuses the image of the object whose temperature is desired in the plane of the lamp filament at F, which is at the principal focus of the ocular lens shown in the eye-piece. By this arrangement the eye will not have to accommodate itself first to the lamp filament and then to the object at a distance, and the lamp filament will appear superposed on the object. To balance the instrument, the current is adjusted by means of a rheostat until the tip of the lamp filament just disappears against the object as a background. Figs. 2, 3, and 4 show the appearance of the filament when too cold, too bright, and just balanced.

Jan 8, 1919

By Frank Drake

Manganese-ores are known to exist in the Caucasus in a number of localities, viz., in the government of Kutais, near the village of Chiaturi; in the same goverilment near the Choruk river, southward from Batum; and in the governments of Erivan and Tiflis. In smaller quantities they are found in various other places also. The first-mentioned deposits are by far the most important; the others being not only less extensive, but remote from present means of communication, and, from their character, expensive to work, although in some cases the ore is of a superior quality. All the manganese-ore now known in the market as a Caucasian " ore comes from Chiaturi, no other deposits in the Caucasus having been worked commercially; movements have been made, however, towards the exploitat,ion of some of those on the Choruk river. The Manganese-Ore District of Chiaturi. General Remarks, Statistics, Etc.—No other known deposit of manganese-ore can approach that of Chiaturi in capacity for producing large quantities of high-grade ore at a low cost. The deposit is said to have been discovered in 1848, by the geologist Abich, but the first shipments were not made until 1879, when 871 tons* were produced. Since that time, the production has steadily increased, until now the world relies on this deposit for about one-half its supply of manganese-ore. The industry is also of great importance locally, and aftords a livelihood to a considerable proportion of the population of the district in which the deposit is situated.

Jan 1, 1899

By T. Egleston

For several years 1 have been engaged in studying the behavior of iron and steel under varying conditions of tension and compression, as well as of shock and abrasion. Some of these observations have been communicated to the Institute at various times. Within the past year I have been looking at the various observations that I have made as a whole, and have been led to the conclusion that there is a regular law of fatigue and refreshment of metals, and that the change which produces either the fatigue or refreshment, is a. chemical one, which is, however, in almost all cases accompanied by physical and molecular changes at the same time. That metals under conditions that were more or less well understood became worthless, has been known for many years. It has been known to blacksmiths that iron and steel, when improperly treated in their fires, become "burned," as they call it, and could no longer be used, and some of them have had a scrap heap into which such material was thrown. A few of them knew that after a period more or less long the iron or steel recovered some of its original properties and could, with many precautions, again be used, but that these phenomena followed any law has not to my knowledge been announced. My attention was first attracted to the varying conditions under which iron and steel rails break in service. It was not long before I became convinced that there was a general law applicable to all metals which allowed of their being used with safety within certain limits, and caused their rupture when the use extended beyond these limits, and this law I have called the law of fatigue- of metals. When me observe the causes of deterioration in iron and steel rails, we find that they are principally shocks, either slight and frequent, like those produced by the passing of a train over a road-bed in good order, which produces a vibration sensible to the ear laid on the rail, for very long distances, but distinctly audible for only a short one; or from sudden and heavy blows, like the descent of the locomotive and each car successively from a high to a low rail.

Jan 1, 1880

By Alfred H. Bell

The year 1936 in Illinois was marked by considerably increased activity in drilling, both wildcat and proved territory, in leasing, and in seismic and geologic exploration. Of the 92 oil and gas wells completed during 1936 in Illinois, 49 were oil wells, 3 were gas wells and 40 were dry holes. This compares with but 34 completions in 1935. The total of the daily initial productions of the new oil wells was 1755 bbl., or an average of 36 bbl. per well. One new field was discovered, the Bartelso field in Clinton County. The leasing of some large blocks of acreage in Clay, Marion, and other counties by the Carter Oil Co. in the late fall of 1935 was followed in 1936 by extensive leasing in southern Illinois by 10 major companies and many smaller companies and individuals. It is estimated that 2½ million acres were under lease by the end of 1936. Seismograph surveying has been carried on by about seven companies, and the number of seismograph parties operating in Illinois has varied from six to eight throughout most of 1936. It is estimated that approximately two million dollars has been spent in the state in seismic and geologic exploration and in leasing during the last quarter of 1935 and all of 1936. Production of crude oil in Illinois in 1936, according to the Bureau of Mines, was as follows: Barrels Barrels January...................... 325,000 July........................ 402,000 February..................... 294,000 August..................... 380,000 March....................... 396,000 September.................. 386,000 April......................... 347,000 October.................... 393,000 May......................... 389,000 November.................. 363,000 June......................... 383,000 December................... 387,000 4,445,000 This 4,445,000 bbl. was an increase of 3 per cent over 1935. Although this increase was due largely to the fact that production was not artificially curtailed, it also reflects some new production and some increases in production from repressuring and water-flooding, which offset the

Jan 1, 1937

By R. A. L. Black

13.8-1. Introduction. Table 13.8-1 shows that production from the African continent is an important part of total world mineral production. In three of the major particular resources listed, diamonds, gold, and cobalt, African production accounts for considerably more than half the world output. Overall, South Africa including South West Africa plays a dominant role in the mineral economy of Africa, other than in petroleum production. Table 13.81 also shows that much of the production is won by surface mining methods. In addition to the minerals listed in Table 13.8-1, Africa is a main world source for the following minerals: [Beryl 33% of total world production Columbium-tantalum 50%" " 1' Platinum group metals 20% l' " 11 Corundum 55%" " " 11 Vermiculite 30% (' " (6 Uranium oxide 15 0/, of free world production] South Africa and Rhodesia together account for nearly all of this production, except for columbium (niobium) of which Nigeria is the main producer. Thus the importance of southern Africa as a major mineral province can readily be appreciated. The consequences of serious political or military conflict between white-dominated southern Africa and the rest of the continent would be grave indeed, particularly for the West whose financial and economic interest in Africa as a whole is very large. The development of mineral resources in Africa involves the same basic elements as are involved anywhere else in the world: exploration, drilling and sampling, metallurgical assessment, and economic evaluation before, if it is justified, a prospect is brought to the productive stage. The same range of factors controls the economic viability of a project in Africa as elsewhere, of which the most important are:

Jan 1, 1968

By H. K. Work, H. T. Clark

The instrument for the rapid determination of carbon in steel, described in this paper, was developed originally to facilitate the operation of the pilot-sized open-hearth furnace in the Jones & Laughlin Research and Eevelopment Laboratory. In this small furnace, with its shallow bath, the drop in carbon is accelerated, and a rapid, reliable test for carbon content is indispensable. This problem becomes rather acute when it is desired to finish heats at a carbon content higher than can be estimated with any degree of accuracy by the fracture test. Several independent methods for determining carbon were investigated, therefore, and it was found that a relatively simple magnetic device could be made to give reproducible results. A laboratory instrument was designed and set up for the use of the furnace operators. It was tested exhaustively in the laboratory and was used with considerable success for following the carbon content in the furnace bath. As soon as sufficient data had been compiled to indicate that the instrument might have a wider application, a more rugged model was constructed and placed in the mill to be tested on commercial heats. Finally, about a year ago, instruments were furnished to the plant open-hearth shops, and these have been in use since that time. As a matter of convenience, the instrument has been named the "Carbanalyzer," and will be referred to by this designation in the following pages. $ Eaklier Investigations While by far the greatest number of magnetic investigations in which the carbon content of ferromagnetic materials was considered have had to do with the evaluation of the magnetic properties of steels of known

Jan 1, 1940

By Herbert Clark Hoover, Lou Henry Hoover

MANY persons hold the opinion that the metal industries are fortuitous and that the occupation is one of sordid toil, and altogether a kind of business requiring not so much skill as labour. But as for myself, when I reflect carefully upon its special points one by one, it appears to be far otherwise. For a miner must have the greatest skill in his work, that he may know first of all what mountain or hill, what valley or plain, can be prospected most profitably, or what he should leave alone ; moreover, he must understand the veins, stringers1 and seams in the rocks2. Then he must be thoroughly familiar with the many and varied species of earths, juices3, gems, stones, marbles, rocks, metals, and compounds4. He must also have a

Jan 1, 1950