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By Paul L. Russell

Of the potential applications of nuclear explosives to mining, excavation is perhaps the most obvious and the best understood, and probably the most practical for use in the near future. Large quantities of rock and earth can be moved by proper emplacement of nuclear explosives, but economic and practical relationship must be determined between the known capabilities of nuclear explosives and the required excavating to remove overburden. On an energy yield basis, even the cheapest of the present commercial explosives cost more than the most expensive nuclear explosive. Comparing the energy yield of a megaton thermonuclear device with the yield of TNT shows that one energy yield per dollar is 400 times greater for the thermonuclear device. However, small-yield nuclear devices (a few 10's of kilotons yield) are less efficient blasting materials than chemical explosives, with the result that the heat of explosion is utilized less effectively. While only 1 lb of conventional explosive is required to excavate 1 cu yd of rock, or about 2 million cu yd per kiloton, nuclear devices excavate from 100,000 to 300,000 cu yd per kiloton. This changes the economic situation, and it is thus apparent that nuclear explosives are cheaper only for the large explosions.

Jan 6, 1964

By Blamey Stevens

(San Francisco Meeting, October, 1911.) My previous paper is entitled, The Laws of Igneous Emanation Pressure. The present paper lays no claim to the exactitude and completeness of a law, since it is of a provisional nature and may be disregarded when experiments have established a basis for more exact reasoning. The general physical states in which aqueous emanations may occur are first considered. The possible physical conditions under which the mineral elements may occur in emanations are then discussed, and a classification of deposits, dependent on emanation, is proposed. A system of scientific experimental investigation is outlined, and it is shown that the physical and chemical properties of emanation may be exactly determined thereby. The investigation is urged as feasible and simple, and not necessarily requiring large and costly apparatus. It is the only step necessary to make possible the formulation of a complete set of laws of igneous emanation. Process of Emanation. In a rising column, magma ranges in temperature from 900° to 1,200°C. Exhalation must begin at some fairly great depth. What this depth may be we can only surmise, since no experimental evidence is available. Exhalation, however, continues as the magma flows upward, until at another level the occluded gases have all escaped. This depth is probably upward of 5,000 ft. (See Fig. 1.) All exhalations must come from between these two levels. As the whole emanation is the sum of the exhalations and residues, the residues must come from below the uppermost level. They will be most abundant when coming, from those parts of the intrusion which have solidified below the lower level.

Apr 1, 1912

By H. C. Goodrich

THE earliest record of copper production from the state of Utah comes from "The Resources of Utah," by. Mr. Fabian, in 1872, wherein it is stated that the. Mammoth mine of East Tintic was located in 1870 and that the ores yielded a large percentage of copper, silver and gold. It is also stated that shipments had been made to Swansea, England, which assayed between $200 and $300 per ton. The Mammoth-Copperopolis mine was located in, 1870 and sold the year following to an English syndicate. Some copper was shipped to. England and in 1873 there was constructed a 15-stamp mill and two copper smelting furnaces; these were operated a few months and before the end of the year were closed down and the property sold for debt. . This property -vas reorganized in 1879 and is at the present day a producer, though its principal product now is lead and silver. While a certain amount of copper has always been coming from the various lead-silver camps of Utah, the real history of copper in Utah should start with the discovery of the mines in Bingham Canyon, located about 25 miles to the southwest from Salt Lake City.

Jan 1, 1925

By A. O. Dady

PRODUCERS of both bituminous and anthracite coal have for many years been worrying about the gradually decreasing consumption of their product in the United States. Twenty years ago production had climbed to a peak of 569,000,000 tons of bituminous and around 90,000,000 tons of anthracite. In 1939 it was about 393,000,000 tons of bituminous and 51,000,000 tons of anthracite. This does not mean that the country is using less polver than it did twenty years ago, or that we are living in colder buildings. As a matter of fact, about three times as much electric power is now being consumed as in 1920. In general two factors are responsible for the drop in coal consumption: (1) greater efficiency in the use of coal, and (2) increased competition from hydro power, internal-combustion engines, and substitution of oil and gas for coal in conventional furnaces. As to the first factor, it took 3 Ib. of coal to generate a kilowatt-hour of electricity in central stations in 1920 and it takes 1.4 Ib. now; it took about 175 Ib. of coal in railroad locomotives to haul 1000 long tons a mile in 1920 where it talces about 120 lb. now: and marked economies have also been made in the use of coal in steel plants: in by-product coke ovens, and in other large uses. As to the second factor, three times as much electricity is produced from water power now as was produced in 1920; three times as much oil is being consumed in various ways; and likewise, the consumption of natural gas has tripled- whereas coal consumption in the same period has dropped by 40 per cent

Jan 1, 1941

G. K. BURGESS,* Washington, D. C.-In the service tests, the Advisory Committee on Aeronautics considered it highly necessary, particularly for seaplanes, to find out whether or not it was necessary to paint exposed parts; reports have been obtained but have not been pub-lished at the present time. Investigations were carried on at three Navy Yards. On just a hurried examination, the inspection was made about two weeks ago and the results are now being digested an examination shows that the aluminum alloys, whether painted or unpainted, stand up very well. It apparently is not necessary to paint, which, of course, is a very important item in the question of the weight of seaplanes. We will be able to report on that, I expect, probably at the next meeting.

Jan 12, 1919

The manpower and time involved in primary blasthole stemming at Kennecott Copper Corp.'s Bingham Canyon mine have been reduced considerable through the use of a mobile stemming machine invented y three mine employees. The patented machine, developed 2% years ago at an estimated cost of $5000 for two units, is the brainchild of Thomas R. Carlson, mine plant superintendent; Alvin J. McIntosh, drilling and blasting engineer; and Jay K. Buehler, field repair general foreman. According to McIntosh, the machine has been well received by the mine employees, who have been relieved of the tedious task of hand shoveling drill cuttings into the blastholes. It is estimated that the stemming machine has saved the mine approximately $25,000 per year in overtime and regular labor costs.

Jan 12, 1976

Colorado School of Mines The, forty-first annual commencement exercises of the Colorado School of Mines were .held at Golden, Colo., on Friday, May 28, 1915. Dr. Lucien I. Blake delivered an address on Epochs in Science. The degree of Engineer of Mines was conferred upon 30 men, and the degree of Master of Science on one man. At the recent annual meeting of the Mining Engineering Society, Massachusetts Institute of Technology, officers were elected as follows: President, K. M. Sully; Vice-President and Treasurer, D. M. McRae; Secretary, H. Solakian. The Student Auxiliary Society of the A. I. M. E. at the University of Kansas, Lawrence, Kan., has elected officers as follows for the year 1915-16: President, Harry E. Crum; Vice-President, Leland E. Fiske; Secretary and Treasurer, Ben A. Sweeney.

Jan 7, 1915

On Saturday evening, Sept. 27, immediately following the Chicago meeting of the Institute, the former students of Dr. T. C. Chamberlain, for 27 years head of the Department of Geology at the University of Chicago, will hold a dinner in his honor. Dr. Chamberlain has recently retired with the title of Professor Emeritus, and expects to celebrate his 76th birthday in September. Further information concerning the dinner may be obtained from Kirtley F. Mather, Granville, Ohio.

Jan 9, 1919

By M. J. Pool

The partial molar heats of solution in liquid tin of cadmium, silver, tellurium, and zinc have been measured at 655°. 700°, and 750°K by liquid-metal solution calorimetry. Silver, cadmium, and zinc are endothermic at these temperatures while tellurium is exothermic. Only the heat of solution of silver depends on composition while all four elements show a temperature-de pendent heat of solution. The heat of solution of tellurium is constant up to 0.6 g-at. pct, becomes increasingly more exothermic, and reaches a limiting value at 1 g-at. pct Te. The limiting value has been used to calculate the heat of formation of SnTe at 750°K. The heat effects associated with the dissolution of the compounds Ag2 Te, CdTe, and ZnTe in liquid tin were measured at 750°K. These values are cotnOined with the measured hat effects at 750°Kfor silver, cadmium, tellurium, and zinc to detertrline the heats of formation of the telluride compounds. Cadmium lelluride exhibits a heat of dissolution which has a compositional dependence. THERE is a considerable amount of interest in the compounds of tellurium because of their electronic properties. Both cadmium and zinc tellurides are thermoelectric materials and considerable work has been done on their electronic properties but a limited amount of data is available on their ther-modynamic properties. This work was undertaken to elucidate the heat of formation data on cadmium and zinc telluride. Since both cadmium and zinc are in Group II it seemed to be of interest to compare the values obtained for them with the heat of formation of a Group I telluride. Silver telluride was selected for this comparison. In the course of the work it was also possible to determine the heat of formation of tin telluride and therefore to make a comparison of some of the Group I, 11, and lV tellurides with the metallic elements silver, cadmium, and tin being in the same period. There is also a great deal of interest in the energetic changes which occur upon addition of solute elements to a common solvent. This investigation provided an opportunity to study the partial molar heats of solution of silver, cadmium, tellurium, and zinc in liquid tin. The partial molar heats of solution are of theoretical interest because solute-solute interactions are a minimum in dilute solutions and application of solution models is simpli- fied. In order to complete the analysis of solute-solute and solute-solvent interactions the temperature dependence of the partial molar heats of solution was also measured. MATERIALS AND EXPERIMENTAL PROCEDURE All materials were of the highest purity available. The silver, zinc, cadmium, and tellurium were obtained from American Smelting and Refining Co. and were reported to be 99.999 pct pure. The silver telluride, zinc telluride, and cadmium telluride were obtained from Atomergic Chemetals Co., a division of Gallard-Schlesinger Chemical Manufacturing Corp., and were electronic-grade material of 99.999 pct purity. Tin used for the solvent bath and for calibration was obtained from the Vulcan Manufacturing Co. and was reported as being 99.99 pct pure. The liquid-tin solution calorimeter used in this work is similar in principle to the differential twin-type calorimeter described by K1eppa.l Two of three identical calorimeter wells are used together during any set of experiments, one well being active and the other being passive. The wells are positioned 120 deg apart in an aluminum calorimeter block. Each well contains a multijunction thermopile and a Pyrex test tube to hold the liquid metal bath. Forty-eight of the thermopile junctions are distributed over the surface of each calorimeter well adjacent to the test tube and serve to integrate the heat effects occurring. The other forty-eight are next to the aluminum calorimeter block. The thermopiles for the three wells are connected differentially so that any change in temperature at the outer junctions (which will be the same for both wells because of the high conductivity of the aluminum block) will oppose for the two wells and result in no shift of the zero. The electrical output represents the true temperature difference between the two reaction vessels. A reaction occurring in the active well gives a comparison with another body of very similar thermal properties. In this way, any spurious heat effects due to slight temperature drifts within the entire calorimeter block are eliminated. The output of the differential thermopile goes to a dc amplifier with multiple ranges of from * 10 pv to 1 30 mv. The output of the amplifier is then fed into a Leeds and Northrup strip-chart recorder. The adiabatic temperature change is then calculated using the technique of Howlett, Leach, Ticknor, and ever.' The aluminum calorimeter block is contained in a cylindrical furnace with main and control heaters

Jan 1, 1965

By Raymond O. Ladoo

FUSED quartz is a glass made by the fusion of nearly pure silica. Some confusion in terminology exists but in the trade today "fused quartz" generally refers to the perfectly transparent colorless product made from rock crystal whereas "fused silica" is a white, translucent product made from silica sand. Vitrified silica is the term preferred by purists for all quartz glass, but it lacks the definiteness of -the trade terms. Since the raw materials, methods of production, and properties of the finished products arc different for the two types, the trade terms are preferred. As fused quartz is amorphous, it-physical properties differ greatly from those of quartz crystal. Lacking crystallographic directions and having no piezo-electric properties, fused quartz. of course, has no value for the making of radio oscillator plates; but it does have other valuable and unique properties. Perhaps the 'best known and most useful properties are its extremely low coefficient of expansion and its ability to transmit short-wave ultraviolet radiant energy. Crystal quartz not only has an aver-

Jan 1, 1947

By James C. M. Li

The Petch relation between the flow stress and the gain size is derived from a consideration of gain boundary sources of dislocations without the need of dislocation Pile-ups. Three mechanisms for inierpreting the yield stress: the gain boundary strength, the unpinning of Frank-Read source near a grain boundary, and the generation of dislocations from the grain boundary are compared and the condition of their equivalence is shown. The effect of the average angle of misfit of pain boundaries is found to be sma11 and so is that of the average angle of misfit of subboundaries having impurities. The effect of impurities on the ledge density in the grain boundary is treated thermodynamically and a relatwn is proposed for the variation of Petch slope with impurity activity. The effect of temperature on the Petch slope is interpreted as due to the change of ledge structure in the grain boundary. It is indicated that the effect of annealing temperature may be more important than that of the test temperature and therefore should be studied. The effect of plastic strain on the Petch analysis is deduced from a work-hardening equation in which the generation of dislocations has first-order kinetics and the annihilation of dislocations has second-order kinetics. It is concluded that the Petch slope will decrease with plustic strain if the rate of annihilation of dislocations is sufficiently large. Critical experiments which may shed light on the mechanism for the Petch relation are suggested. THE relation between the yield or flow stress, 0, and the grain size, l, was first proposed by all' and later studied more extensively by Petch and co-workers, who also proposed a similar relation for the fracture stress and deduced from these a grain-size effect of the ductile-brittle transition temperature. The microscopic mechanism used by all' and petch2 involves a pile-up of dislocations of like sign generated from a Frank-Read source. The yielding or flow takes place when the pile-up exerts sufficient stress at the grain boundary so that the plastic deformation can propagate from one grain to another. If the average strength of the grain boundary is ai and the average length of the pileup is lp, the Petch slope, k, is given by" where p is the shear modulus, b the Burgers vector, and v the Poisson ratio. This slope will be independent of the grain size if l/lp is a constant. This is possible, since, if the Frank-Reed source is situated near the grain boundary, lp = 1, and if it is situated in the middle of the grain, Ip = 1/2. cottrell,12 also using the pile-up mechanism, proposed that the stress concentration at the grain boundary will initiate Frank-Read sources near the grain boundary and in this manner a Lüders band can propagate from one grain to another. Assuming that the average distance between the Frank-Read sources and the grain boundary is 1, and the unpinning stress of the Frank-Read sources is op, Cottrell obtained the following Petch slope: This slope will be independent of the grain size if ls is independent of the same, which is not as obvious as the condition, Ip = I for Eq. [2]. In addition to this assumption, the direct relation between the Petch slope k and the unpinning stress, up, was recently questioned by Johnsonon grounds that it is inconsistent with the following observations: the independence of k with temperature and strain rate, and the small k in columbium, which, like iron, has a sharp yield point. As pointed out by ohnson," the most important objection both to the Hall-Petch mechanism, in which the strength of the grain boundary plays the role in yielding, and to the Cottrell mechanism, in which the unpinning of Frank-Read sources plays the role in yielding, is the lack of direct observation of the pile-ups. The dislocation structure in deformed iron has been examined recently in the electron microsope.'-' Dislocations appear to be generated from grain boundaries or other interfaces; they form clusters and tangles within the grain at very early stages of deformation, even in the Lüders band, if the deformation is slow or at normal and elevated temperatures. Although it is still too early to interpret bulk properties from thin-film observations, it does seem worthwhile to look for a mechanism for the Petch relation which does not require dislocation pileup. SUBBOUNDARY SOURCES In order to show that a consideration of grain boundary sources can lead to the same Petch relation as does the consideration of the strength of the grain boundary, we shall first discuss the case of a simple tilt boundary whose elastic properties have been studied in detail.17 The strength of a partially

Jan 1, 1963

By C. K. Leith

CERTAIN ideas on iron and steel sanctions to follow originated in a series of conferences held under the joint auspices of the War Department and Brookings Institute in Washington last spring. The views presented may be regarded as those of substantial segments of the steel industry. In view of the fact that steelmaking capacity can be so quickly converted to the production of armament, any effective control must necessarily include the entire steel industry and not solely the parts devoted to the production of implements of war. It must also be exercised all the way from production and shipment of raw materials through their ultimate conversion into finished products and use. Control will be dis- cussed under two main headings: (I) control of raw materials at the source; (2) control of steel capacity within the Axis countries.

Jan 1, 1944

By J. L. Perry

FOR many years, you and your fellow members of the American Institute of Mining and Metallurgical Engineers have devotedly and ably applied yourselves to the art of making iron and steel. having foremost in your minds the conservation of raw materials, suitable and efficient facilities, economical processes, and improved quality of product. For the past three strenuous years you have contributed wholeheartedly to meeting the problems of increased production. You have conducted scientific and technical investigations and research, recommended experiments. and gathered all the available and valuable information possible to gain the desired objectives. You have had many obstacles and difficulties to overcome. In the early days of your organization, there was some lack of co-operation from the industry itself-perhaps, for example, some failure to recognize the mutual advantages of free exchange of experiences and information. But regardless of any hindrances, you have made many and valuable contribution which have tended to make iron and steel manufacture leas of an art and more of a science.

Jan 1, 1944

By J. B. Dilworth

In estimating the investment-value of a mining-property or plant, the value of which decreases with operation, it is often necessary to know the sum which must be set aside periodically from earnings either to renew the plant at the end of its life, or to return the capital involved when the earningpower of the investment has ceased. In such cases it is manifestly incorrect simply to divide the total amount to be retired by the 'number of periods (usually years) during which the investment shall be active, as the sums periodically withdrawn have a certain interest-earning power varying with the length of time they are held and with the opportunities afforded for their investment. But though the interest may be considered to accumulate regularly year by year, yet the rules and tables for compouiid interest do not apply, owing to the addition of a fixed amount of new money to the total at the beginning of each period. Briefly stated, the problem of sinking-funds is, to find the amount of money which must be periodically set aside at a certain rate of interest, regularly compounded, to yield a certain sum in a given length of time. In most practical cases the interest is compounded and the fresh amount added at the same time—usually once a year—and on this basis the problem may be solved as follows : Let S = total amount to be retired, Let T = interest rate : R = 1 + r, Let n = life of tlie sinking-fund or the amortization-period, Let L = the sum set aside at the end of each year. Then the amouilt of the sinking-fund at the end of first year is 2, which at the end of n years will have illcreased by compound interest to IRn-l. Similarly, another amount, x, will be set aside at the end of second year, which will in turn increase

Jan 1, 1911

By Walter O. Snelling

IN combating mine-fires the use of carbon dioxide as a means of producing an atmosphere in which combustion cannot be sustained, has been many times suggested and frequently tried, generally with a fair degree of success. The carbon dioxide is produced by acting on limestone with dilute sulphuric acid, large wooden boxes being used to hold the limestone, and arranged in such a manner that one box may, be cleaned and refilled with blocks of limestone while another is being used in generating the carbon dioxide. The gas is led by means of pipes of large diameter to the location of the fire, tight brattices having been previously put up as close to the fire as possible on every side, so as to limit the space to be filled with the .gas to the smallest possible volume. The cost of producing Carbon Dioxide has been, however, a decided draw-back to the use of this method, and the danger of producing carbon monoxide by the reduction of the carbon dioxide by heated carbon, and consequently bringing about an explosion, has also tended to prevent the application of this method. The use of sulphur dioxide in combating mine-fires has not, I believe, been previously suggested or tried, and yet the method presents such decided advantages over the use of carbon dioxide that it seems proper to suggest the advisability of considering it as a cheap, convenient, and safe means of fighting stubborn mine-fires. 1. Cost, Preparation, etc.-One ton of brimstone, costing from $20 to $30, will produce about 25,000 cu. ft. of sulphur dioxide gas, and allowing for all sources of loss it is probable that sulphur dioxide gas can be produced for about $1,300 per 1,000,000 cu. ft. For carbon dioxide gas, produced by the action of sulphuric acid on limestone, a good estimate would be $4,000 per 1,000,000 cu. ft., provided that sulphuric acid

Sep 1, 1908

Discussion of the paper of L. C. MORGANROTH, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 93, September, 1914, pp. 2345 to 2352. D. T. DAY, Washington, D. C.-I would like to hear some further detail as to the California deposits. L. C. MORGANROTH, Pittsburgh, Pa.-We have examined the California deposits at various times; I have been over practically all of them myself. These deposits are all of the massive variety. While it is possible that it could be mined and used for metallurgical purposes, it is not feasible because it costs too much. At the present time magnesite which is mined in California is used in the making of plaster, or by the paper trade. Careful figures show that if the California magnesite could be delivered to Atlantic seaports in the crude state at not over $4 a gross ton, and assuming that it would give the same results as the Austro-Hungarian magnesite, it would be cheaper to use the latter. It is also more difficult to dead-burn the massive magnesite, for while it starts to give up its gas readily, the difficulty consists in driving off the last few per cent., and unless this is driven off the magnesite will absorb C02 from the air, so that in a few months it may have 10 or 12 per cent. DAVID T. DAY.-How is the Austro-Hungarian supply at the present time ?

Jan 4, 1915

Samuel T. Wellman, Cleveland pioneer steel man, who was often referred to as the "father of the open-hearth process of the United States," died suddenly on July 11, 1919, of heart disease, at Stratton, Me. For more than half a century, he was closely identified with the improvement of equipment used in the making of steel and contributed a number of inventions that virtually revolutionized the industry. Mr. Wellman was born Feb. 5, 1847, at Wareham, Mass., his father at the time being superintendent of the Nashua Iron Co., Nashua, N. H. After attending public school and a year at Norwich University, he served in the Civil War as a corporal of the first New Hampshire Heavy Artillery. He went to Pittsburgh in 1867 and assisted in starting the first crucible steel melting furnace built in America at the works of Anderson, Cook & Co. It melted a ton of steel with an average of 1000 Ib. of nut coal, which cost less than $1, while the melting of a ton of steel in crucibles in the old fashioned coke furnace took three tons of the very best coke, costing from $2 to $3 per ton. This furnace was a great success and in a very few years had driven the coke furnace out of use. From Anderson, Cook & Co., Mr. Wellman went to the Singer, Nimick & Co. works, Pittsburgh, where he built two crucible steel melting furnaces of the same type. After that he spent some time in the office of the Siemens agents in Boston and also at steel works in different parts of the country, starting crucible steel furnaces. He then went to the Bay State Iron Works in South Boston, Mass., where he built the first open-hearth furnace that was a commercial success in the United States. It made steel of a much better quality than had previously been made in this country. The principal use to which it was put in those days was the manufacture of locomotive fire-boxes. From South Boston, he went hack to the old works in New Hampshire where his father was still superintendent, and built for it an open-hearth furnace, a plate mill, and a bar mill. In 1873, Mr. Wellman went to Cleveland to design and build the plant of the Otis Steel Co. He remained with this company for 16 years as engineer and superintendent. During this time he developed the open-hearth charging machine and introduced the electromagnet for handling pig iron and scrap steel. The first charging machine was operated by hydraulic power, and although it was not entirely satisfactory it performed the work fairly well and encouraged its inventor to build another one, which was driven by electric motors. This proved

Jan 1, 1920

CARL A. WENDELL, New York, N. Y. (written discussion*) .-I have never seen in print anything that even remotely has approached this article in clearness and important conclusions in conjunction with work done on the sink-and-float test. I have had many hundreds of these tests made and on different specific gravity solutions and the resultant product analyzed, but I have never grasped nor been able to show what this article sets forth. This article brings out one factor very clearly to my mind; what is to take the place of the solutions of different specific gravities used to obtain the laboratory results, when it comes to washing on a large scale, since water has one constant weight only? The answer is, sizing of coal. And as we know the importance of size versus specific gravity of the material to be washed, perhaps defined (practical) lines can ultimately be gotten up so that the sizing, if any, may be determined at the same time as the laboratory work on the coal is being done. G. R. DELAMATER, ? Steelton, Pa. (written discussion?).-The authors' deductions are well founded and although they disclaim any wide experience in commercial coal washing, practically all of the data presented are applicable to coals of all parts of this country. The paper clearly sets forth the great necessity of careful preliminary investiga-tion of each contemplated washery undertaking and contains the follow-ing very true statements. "It is not safe to assume that any coal which can he successfully washed on coarse coal jigs can be cleaned more com-pletely by washing at a finer size on tables," and "The effect of finer crushing upon the completeness with which impurities may be separated from coal depends upon two opposing tendencies. First, that the more finely a raw coal is crushed, the more completely will the particles of impurities be detached from the particles of clean coal. Second, the finer a coal is crushed the more difficult it becomes to separate the pieces of clean refuse from the pieces of clean coal."

Jan 12, 1919

By James Howe

EVERY engineer and user of wire rope is desirous of information that will enable him to determine whether the performance of any particular piece of rope is satisfactory, and what conditions can be changed so as to increase the life of a rope. In most cases, it is far from easy to analyze the conditions of service and tell which is the greatest factor in determining the life of wire rope. If we start on a layout for an entirely new rope system, the task of making conditions satisfactory is simplified so far as the engineering details are concerned; but if the plant requiring wire rope is in operation, any change is likely to involve the expenditure of consider-, able money to replace and change over machinery that must be kept in constant operation, because a large monetary loss will result from a shutdown for even a few days. Often wire rope is kept operating under bad conditions, as the user thinks that it is cheaper and quicker to replace the rope than to make alterations in the hoisting machinery. A typical case is a metal mine operating in what is now almost the center of a large mining city, where it owns a few acres of mineral rights. It was expected that the shaft would go to a depth of 1000 ft. (305 m.), so a moderate sized rope, about 1 ¼ in. (31.7 mm.), was used on a 6-ft. drum with a 7-ft. head-frame sheave and rather short lead from drum to head sheave. This mine has gone deeper each year until, it is now 2500 ft. deep and the rope speed has been increased from 1500 ft. per min. to over 3000 ft. The original rope just filled the drum in one layer, now it overwinds three layers. The original ropes were probably 6 X 19 crucible steel and lasted from 12 to 18 mo.; now, the highest grade plow steel is used, yet the average service is only about 6 mo. The cause is not hard to find. If the engineers had known at the outset what would be done with this hoist, the design would have been very different. Conditions at this mine, from a wire rope standpoint, have gradually become worse and it is difficult to see how rope service on this hoist can be com-pared with the service of previous years with any fairness to the wire-

Jan 2, 1922

By Paul M. Tyler

OF THE 92 elements generally accepted by chemists as constituting the primary building blocks of matter, all but the very rarest have been investigated with a view to employing them in steel manufacture. The surprising thing is that so few have been found commercially acceptable. Despite the relatively small number of elements involved, the use of alloys in steel making is one of the most complicated and probably one of the least well understood of modern industrial enterprises. The action of individual elements in steel making has been described often and a profuse and somewhat acrimonious literature covers pretty much the whole field of ferroalloy ore supplies. In the middle ground between the miner and the -steel maker developments are less carefully watched by most observers and except for an occasional description of the technique of some conversion process or the tariff hearings in Congress, little is said about them. The present paper has been submitted in the hope that it will stimulate broader constructive economic thinking. It undertakes to describe in' relatively nontechnical terms this great and growing though highly complex industry and to study its relations to national progress.

Jan 1, 1932