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By John Roberts

THE Federal income tax law permits as a deduction in determining net income "in the case of mines, . . . a reasonable allowance for depletion and for depreciation of improvements, according to the, peculiar conditions in each case, based upon cost, including cost of development not otherwise deducted: Provided, that in the case of such properties acquired prior to Mar. 1, 1913, the fair market value of the property (or the taxpayer's interest therein) on that date shall be taken in lieu of cost up to that date." The law provides for a reasonable allowance but the regulations provide for a definite method of computation that possesses more the virtue of simplicity than that of reasonableness. Article 210 of Regulations 45. reads: "When the cost or value as of Mar. 1, 1913, or within 30 days after the date of discovery of the property shall have been determined, and the number of mineral units in the property as of the date of acquisition or valuation shall have been estimated, the division of the former amount by the latter figure will give the unit value for purposes of depletion, and the depletion allowance for the taxable year may be computed by multiplying such unit value by the number of units of mineral extracted during the year." This is simple, but is it reasonable? The intent of the law is clearly that the cost of the ore in the ground shall be considered as part of the cost of the same ore when removed and sold. The regulations fail to carry out that intent, because of the unwarranted assumption that all the ore in the mine cost the same amount per ton. This is what gives the Treasury Department's method its simplicity, but at the same time robs it of its reasonableness because the assumption is contrary to fact.

Jan 1, 1921

By Ernest F. Burchard

In connection with the work of testing structural materials for the use of the U. S. government at the laboratories of the technologic branch of the U. S. Geological Survey at St. Louis, Mo., from September, 1904, to April, 1909, and since then at Pittsburg, Pa., large quantities of sand, gravel, and crushed stone have been needed from time to time, besides samples of building-stone, clays, and other quarry-products. In many instances it has been necessary to obtain single samples of sand, gravel, or crushed stone in lots of a car-load or more. For obvious reasons all these collections have had to be made by a representative of the Survey. As the work progressed it was found essential that numerous geologic data should be gathered regarding the materials collected, in order that they might be properly classified as to kind of material, source, geologic age, etc., and that they might be rated according to quantity available, accessibility to transportation facilities, approximate costs, suitability for special purposes, etc., and that notes might be taken regarding undeveloped deposits of possible value. Furthermore, it mas desired that the selection of materials for tests should be made broadly, so as to cover, first, the representative types of material, and later, if possible, the typical materials of the more important building-centers in the United States. In order to insure a certain degree of uniformity in this work and economy of effort and expense, it was decided that as much of the sampling as was practicable should be done by a member of the geologic branch, whose regular field-trips could be combined conveniently with those necessary for procuring materials for the laboratory. During parts of the last three years 1 have been engaged in field-work of this sort.

Jan 1, 1911

By C. F. Quest, T. S. Washburn

The steel industry has a definite need in its tonnage mills for a formula relating expected tensile strength to the analysis of the steel. The McWilliam-Barnes1 and other less comprehensive formulas are used for this purpose, but these formulas were designed for an analysis range that does not include the medium manganese and silicon-bearing steels. This type of steel is being produced to meet the demand for tensile strength slightly higher than that of ordinary structural steel but not high enough to justify expensive alloy steels. The purpose of this paper is to present a somewhat more comprehensive formula based on data accumulated over a number of years by the Inland Steel Co., and to discuss the method followed in obtaining a formula to fit the data. The resultant formula admittedly is still weak in some respects, but for the expanded analysis range appears to be an improvement over the other formulas. It is hoped that with the collection of more data and possible collaboration with other mills studying this problem it will be possible to work out a more nearly perfect formula. Several publications have been issued on this subject. In some, the equation type of relation was evolved while others made a combination of tables and an equation. The latter include work by Campbel12,3 and Webster.4,5 Campbell classified the steels as acid and basic and applied a different formula to each. For basic steels, he used the equation: Teosile etrength = 41500 + 770C + 1000P + yMn [1 y was a variable depending on the carbon and manganese content of the steel and was listed in tables. Webster investigated acid Bessemer steel and developed the equation: Tensile strength = 38000 + 800C + xTP+ yMn [2]

Jan 1, 1940

By C. P. Gazzara and

The modulus of elasticity and yield strength of commercially pure, annealed titanium sheet was investigated at room temperature as a function of strain rate and direction of loading. The value of E varied with direction of measuremeni in the sheet but was unaffected by strain rate in the range 0.04 x 10-to 10-2min-1. The yield strength increased with increase it2 strain rate and varied with specimen orientation. VALUES of the modulus of elasticity, E, in tension for commercially pure titanium have been reported at from 14 to 20Xl06 psi.' Reasons suggested for this variation have been a) composition, b) strain rate, c) texturing, and d) creep. For example, alloys of titanium with aluminum, manganese, and nitrogen have yielded modulus values of from 12.5 to 16.8 x lo6 psi at room temperature.' It was shown by Klier that the modulus in titanium plate was sensi-tive to strain rate. while Dotson and kattus meas- ured variations in E as the strain rate was increased from 3X to 60 min-l. For RC-7OA, 0.040-in. titanium sheet at room temperature Dotson and Kattus found that the average values of E, for specimens in the rolling direction, increased from 14.7 to 16.0 X lo6 psi as the strain rate increased. Simultaneously, the 0.2 pct yield strength increased from 74,700 to 95,700 psi for the same specimens. Differences in yield strength and E have been reported as a function of directionality in titanium sheet.= Dotson and Kattus report such an effect, and Feola6 found in annealed titanium sheet marked anisotropy in tensile strength, yield strength, reduction in area and elongation at room temperature, with

Jan 1, 1961

By C. K. Leith

THE questions as to what grades of ore it pays to conserve for the future, and the valuation of low-grade reserves, are becoming immediate and definite as applied to individual ore deposits, and seem to call for some sort of quantitative answer. Both opinion and practice involving these questions differ widely. The number of variables in this problem is so large that final solution will perhaps never be agreed upon, yet there seem to me to be certain controlling factors which can be placed in quantitative relation and serve to reduce the number of variables which it is necessary to consider in a given instance. I assume that it will not pay either for the individual or for the State to conserve any ore when the present cost of conservation (by stock piling or otherwise), when compounded at 6 per cent. interest for the number of years which would elapse before this ore is used, will exceed the profit which the ore will yield when it is used. It may be urged that any loss to the individual may be made up in gain to the State. This might be true if there was any definite limit to the amount of iron ore, but when we remember that iron makes up .4 per cent. of all the rocks of the earth and the amount of rock carrying iron in excess of 20 per cent. is for practical purposes, unlimited, it is apparent that posterity is assured of its iron ore. The changes will be mainly in methods and cost of extracting the ore. Therefore, any expenditure of money or effort now, which when compounded will exceed the worth of the effort or money needed in the future to utilize the iron, is a net loss both to the individual and to the community.

Jan 2, 1914

By M. E. Volin, D. W. Fuerstenau, A. L. Mular

This paper presents the results of an investigation of the effect of feed size on the integral rate at which feed material is dry ground in a laboratory rod mill. The data are interpreted in terms of the Gaudin-Meloy distribution equation. The equation, Mo — Mt/t = Aoxo r-1, is found to hold for feed sizes smaller than some critical size or for grinding times larger than some critical time. It is shown that a feed grindability is related to this critical size, which appears to be the transition between predominately impact and predominately attrition grinding. Detailed research on feed size effects in comminution has been rather limited. Gaudin1 ground single-sieve fractions of quartz for extended time periods (four hours) in a laboratory ball mill. His work, which was designed to study the nature of size distributions, showed that there is a critical feed size above which comminution occurs primarily by attrition. For his system, the critical size was about 2-mm when using 22-mm balls. In a more recent investigation2 single-sieve fractions of quartz were ground in a laboratory rod mill for constant time periods (15 min) to determine how feed size affects the grindability of the material. This work showed that grindability is essentially independent of feed size in the rod mill after this moderately long grinding period. To further clarify this observation, a study in which feed size and grinding times are varied over a fairly wide range, and particularly, a study of the dependence of the integral rate of grinding on feed size during the initial stages of rod milling is necessary. For an analysis of such data, it is desirable to use a parameter which is very sensitive to change during the initial grinding period when reduction ratios are

Jan 1, 1964

By C. F. Quest, T. S. Washburn

The steel industry has a definite need in its tonnage mills for a formula relating expected tensile strength to the analysis of the steel. The McWilliam-Barnes1 and other less comprehensive formulas are used for this purpose, but these formulas were designed for an analysis range that does not include the medium manganese and silicon-bearing steels. This type of steel is being produced to meet the demand for tensile strength slightly higher than that of ordinary structural steel but not high enough to justify expensive alloy steels. The purpose of this paper is to present a somewhat more comprehensive formula based on data accumulated over a number of years by the Inland Steel Co., and to discuss the method followed in obtaining a formula to fit the data. The resultant formula admittedly is still weak in some respects, but for the expanded analysis range appears to be an improvement over the other formulas. It is hoped that with the collection of more data and possible collaboration with other mills studying this problem it will be possible to work out a more nearly perfect formula. Several publications have been issued on this subject. In some, the equation type of relation was evolved while others made a combination of tables and an equation. The latter include work by Campbel12,3 and Webster.4,5 Campbell classified the steels as acid and basic and applied a different formula to each. For basic steels, he used the equation: Teosile etrength = 41500 + 770C + 1000P + yMn [1 y was a variable depending on the carbon and manganese content of the steel and was listed in tables. Webster investigated acid Bessemer steel and developed the equation: Tensile strength = 38000 + 800C + xTP+ yMn [2]

Jan 1, 1940

By Gherman Pavlovich Nikonov

Results of preliminary research on the use of small diameter water jets at high pressure for cutting rocks has demonstrated the possibility of effective cutting of anthracite. Detailed research has, therefore, been conducted at the Skotchinsky Institute of Mining to study the dynamics and structure of the small water jets and the mechanism by which they cut coal. One of the objects of this research was to obtain data for the design of a machine for cutting rock, based on the same principles as that for cutting coal. The productivity of water jet mining machines depends on the hydro- dynamic parameters of the jet. Therefore, the research on small diameter water jets was directed, initially to a study of the nature of the variation of these parameters, and to obtain a profile of dynamic pressure distribution over the section of the jet. As has been confirmed previously, the required jet pressure (to cut coal) lies in the range of 100 to 500 atmospheres. These pressures were utilized for the research. The diameter of the nozzle was changed as ~follows; 0.97; 1.24; 1.5; 2.17; 2.87; and 3.57 mm. Graphs showing dynamic pressures for each nozzle diameter and varied axial dynamic pressure were obtained over distances ranging from 2 to 70 cm from the nozzle. One of the most important hydrodynamic parameters of a jet, closely related to the dynamics of jet disturbance in air, is the magnitude of the axial dynhmic pressure. A study of the variation in this pressure with increasing distance from the nozzle led to the separation of the jet into three specific parts, which differ from each other not only in the nature of the change in dynamic pressure, but also in structural properties.

Jan 1, 1971

By R. L. Fleischer

IN 1925 a criterion for localized deformation in a single crystal was derived by Taylor and Elam.' They noted that for a single active slip plane the slip plane area is constant, but the direction of the stress with respect to the slip direction changes during deformation so that, when the increase in stress due to this rotation is large enough relative to the work hardening, instability occurs. (By instability is meant continued slip on the active slip plane.) The instability criterion may be written t>dt/d?/m tan2? [1] where t and ? are resolved shear stress and strain, m the Schmid factor for resolving shear stress, and ? is the angle between the slip direction and the axis of tension. The formula points out that regardless of the atomic mechanism involved, for large flow stresses and low work hardening rates, slip on a single plane—once started—should continue. The case of alloying provides a direct possibility of adjusting the parameters in Eq. [I]: As an alloying element is added to a pure metal, the flow stress is raised and the work hardening in easy glide may be either decreased2 or unaltered.3 Since flow stresses in easy glide may rise to the kg/mm2 range for alloy crystals while easy glide slopes may be less than % kg/mm2, 2 it is possible for the inequality to be satisfied. Indeed Garstone and Honeycombe3 report that slip becomes coarser with increasing stress in the easy glide range, where the flow stress would be increasing and the slope would be essentially constant. Another case where high flow stresses and low hardening rates accompany coarse slip is that of quench hardening.4 Maddin and Cottrell report that quenched aluminum crystals display slip markings resembling those of a brass. A similar effect has been observed after irradiation.'

Jan 1, 1960

By C. F. Quest

THE steel industry has a definite need in its tonnage mills for a formula relating expected tensile strength to the analysis of the steel. The McWilliam-Barnes1 and other less comprehensive formulas are used for this purpose, but these formulas were designed for an analysis range that does not include the medium manganese and silicon-bearing steels. This type of steel is being produced to meet the demand for tensile strength slightly higher than that of ordinary structural steel but not high enough to justify expensive alloy steels. The purpose of this paper is to present a somewhat more compre-hensive formula based on data accumulated over a number of years by the Inland Steel Co., and to discuss the method followed in obtaining a formula to fit the data. The resultant formula admittedly is still weak in some respects, but for the expanded analysis range appears to be an improvement over the other formulas. It is hoped that with the collec-tion of more data and possible collaboration with other mills studying this problem it will be possible to work out a more nearly perfect formula. Several publications have been issued on this subject. In some, the equation type of relation was evolved while others made a combina-tion of tables and an equation. The latter include work by Campbell2,3 and Webster.4,5 Campbell classified the steels as acid and basic and applied a different formula to each. For basic steels, he used the equation: Tensile strength = 41500 + 770C + 1000P + yMn [1] y was a variable depending on the carbon and manganese content of the steel and was listed in tables, Webster investigated acid Bessemer steel and developed the equation Tensile strength = 38000 + 800C + xP + yMn [2]

Jan 1, 1940

In March 1956 a conference on geochemical methods of prospecting for ore deposits was held in Moscow. This conference was the culmination of a ten-year period of extremely rapid increase in both research and routine application of geochemical prospecting methods in the USSR. This activity was divided among groups centered in extremely widely separated bases of operation, ranging from Moscow and Leningrad in the West, Yerevan in the Caucasus, and Alma-Ata in Central Asia to Chita near the Manchurian frontier in the Far-East. The All-Union Conference on Geochemical Methods of Prospecting for Ore Deposits, as the meeting was called, was the first opportunity for these scientists from many parts of the country to meet and exchange experiences. It also served to introduce members of the different research laboratories located in the city of Moscow itself, where adequate channels of technical communication had not yet been established. As a result of the Conference, it was resolved that a concerted effort should be made for the participants to publish the results of their work. Two books have appeared as a direct response to this resolution. I. I. Ginzburg prepared a synthesis of the field of geochemical prospecting for minerals based on the material presented at the Conference. This volume has been translated into English and is now available. In addition, the individual papers presented at the Conference were assembled into a symposium volume and published in 1957 under the editorship of V. I. Krasnikov. Unless otherwise noted, these two books have supplied the source material for the present appraisal of the status of geochemical prospecting in the USSR. It is thus about four to five years old. In the years following the conference, the literature has carried a substantial volume of technical papers, together with a few monographs pertaining to specialized aspects of geochemical prospecting.

Jan 6, 1960

By J. A. Herbst, K. Rajamani, Y. C. Lo

In spite of potential theoretical and economic advantages of large-diameter ball mills, many manufacturers elect not to build them owing to what is perceived as an excessively large design risk. This is because traditional predictions for mill scaleup to large diameters are not always accurate. Alternative methods of analysis and scale-up are required. Recent studies have shown that detailed population balance models which account for important grinding subprocesses (grinding kinetics, material transport, and classification) are capable of predicting the performance of small- and intermediate-diameter mills (up to 4.3 m, or 14 ft) from small-scale batch tests. These same models are used in the current study to predict the performance of a "borderline "large ball mill (4.7 x 5.5 m, or 15 x 18 ft) at Asarco's Sacaton operation, a ball mill (5 x 5.8 m, or 16.4 x 19 ft) at Kennecott's Chino operation, and one of the world's largest ball mills (5.5 x 6.4 m, or 18 x 21 ft) at Cities Service Pinto Valley operation. Model parameters required for scale-up have been estimated in a 380-mm-diam (15-in.-diam) batch mill. Predictions are compared with the results of detailed plant sampling in the three plants. For the Sacaton and Chino operations, the error of the predictions was found to be less than 2.5%, while the corresponding error for the Pinto Valley operation was less than 2.7%. It is concluded that proper representation of the major subprocesses of grinding in the model equations is the key to achieving accurate scale-up. Of special importance is the need to account for the size distribution of the grinding media and the influence of the size distribution environment in the mill on grinding kinetics.

Jan 1, 1986

By William C. Maurer

A survey of 25 novel drills has shown that spark drills have potential for drilling oil wells and blastholes at higher rates than rotary drills. Available laboratory and field data were extrapolated to drilling rates of 70 to 280 fph for full-scale spark drills. Most of the data used in these extrapolations were from small-scale laboratory tests at atmospheric pressure. Accurate extrapolation of the small-scale spark drill tests to full-scale field drills was complicated by the fact that the effect of fluid pressure in the well bore and the effect of spark size were not known. In order to answer these questions and to more accurately evaluate the potential of spark drills for drilling blastholes and oil wells economically, a high-voltage spark discharge system was assembled. This equipment produced powerful sparks (10,000 joules) equivalent to those that would be used on a 100-kw full-scale field drill. These sparks are 100 times more powerful than those previously used on spark drills, thus eliminating extrapolation of the spark size. In addition, a pressure chamber was modified to enable using these sparks to produce craters in rocks at fluid pressures up to 15,000 psi, thus eliminating extrapolation from atmospheric pressure to the high pressure existing in deep oil wells. These tests have provided considerable information for more accurately evaluating spark drills for oil-field drilling. MECHANISM AND THEORY OF SPARK DRILLING Spark-Drilling Mechanism When a high-voltage capacitor is discharged across two electrodes, the dissipated energy produces a high-temperature, high-pressure plasma for a few µsec. When these sparks are discharged in air, they undergo considerable expansion (Fig. 1) and produce low-pressure pulses (103-

Jan 1, 1970

By V. Lepetic, C. C. Harris

A systematic program of investigations covering all aspects of cell hydrodynamics,1-3 flotation kinetics,4,5 surface chemistry and their interactions has as a major objective the elucidation of the flotation micromechanism and the principles of cell design and scale-up.6 Purely from the scale-up point of view, a family of reactors should enable different throughputs of the same material to be similarly treated or, at least, to be treated in a manner which differs beween reactors in a predictable way. Thus, for the same material and residence time, the recovery and grade from differently sized cells of the same family should, ideally, be similar or, at least, be related to each other in a known way. It is well known, however, that different-sized cells do not always achieve similar results, and it is necessary to enquire into the reasons for these differences. For example, it may be that the relative dimensions of different-sized cells result in hydrodynamic conditions which preclude similarity; if so, different scaling may improve the situation. The major question concerns identifying the dynamic conditions and their associated geometric requirements which govern the flotation process, and the criteria which are necessary for their fulfillment. It is to answer such questions that the program referred to earlier was instituted. In connection with this program and in order to examine data concerning the physical features and operating conditions of existing flotation cells, the following survey was carried out. This work represents an approach which is complementary to experimental investigations, for it recognizes that the design of existing cells may embody several of the principles being sought. If data for enough cells, especially families of cells, are examined, some broad requirements common to all cells may emerge.

Jan 9, 1966

By F. E. Bash

WHENEVER electric and open-hearth steel men discuss the relative advantages of their respective methods, the question of temperature is always discussed, so that this paper is written in the hope that definite data may settle some of the questions and encourage further investigations along these lilies. The writer has had the opportunity of taking the tapping temperatures of steel from electric furnaces of different sizes in various plants and from a number of open hearths handling the same kind of steel. All temperature measurements were made with the same disappearing-filament type optical pyrometer and the corrections for emissivity applied were those worked out by Burgess,1 which are 0.40 for steel streams and 0.65 for slag. The correction is applied by calculating the curve giving the relation between the true and apparent temperature in the following formula: Log E = CZ log e( 1 _ 1 x \T2 T1) in which E = emissivity; C2 = 14,500; e = base of Napierien logarithms; ? = wave-length of light used = 0.65/4; T2 = true temperature, in degrees absolute; T,1 apparent temperature, in degrees absolute. The curve showing the relation between true and apparent temperature for steel and slag arc given in Fig. 1. For the purpose of comparison of open-hearth and electric furnaces, there are given in Table 1 the tapping temperatures of two 25-ton Heroult electric furnaces and one 6-ton with one 50-ton acid, one 40-ton basic, and one 65-ton acid open-hearth furnace, all making nickel ordnance steel for guns. The two 25-ton Heroult electric furnaces were finishing steel refined by the triplex process and the 6-ton Heroult finished steel that was partly refined in an open hearth.. In this table, the tapping temperature and the temperature of the steel stream into the first ingot

Jan 9, 1919

By Z. F. Oszter, D. Vincent, W. K. Behrands

With the expansion of open pit operations, belt conveyors are going to be used in the 13 608 to 18 144 t/h (15,000 to 20,000 stph) capacity range, which calls for a review of some of the horsepower calculation methods. This paper presents methods (based on German research data, field tests and theoretical considerations) for the evaluation of the Ky factor in the CEMA formula for belt conveyors of large carrying capacity, which fall beyond the limits of the data given in tables in the CEMA book. (The CEMA limits are 407 N\\m (300 lb ft) and Tave = 7.3 Mg (16,000 lb). At these large loads, the impression resistance of the belting on the idlers plays a major role, which in turn influences the magnitude of the drive horse power required. An example will illustrate the order of magnitude difference of the horsepower values obtained by using a conventional calculation method and the suggested method, as well as the beneficcia1 influence of the 4-roll idler in comparison to the standard 3-roll unit for a large caving capacity belt conveyor. This paper concerns itself with the analysis of the resistance to motion of belt conveyors, emphasizing the evaluation of the frictional resistance to motion due to load and belt pressure on the idlers and the flexing resistance of the belt and material when passing over the idlers. In the case of long and heavily loaded belt conveyors, the aforementioned resistances reach extremely high values calling for close analysis of the phenomena, presently not calculable with normally used formulas. This paper establishes correlation between experimental and empirical data presenting practical formulas a tool for the designer of high-capacity belt conveyors. The application of the formula is illustrated in an example in the Appendix.

Jan 1, 1981

By J. E. Burke

THE origin of so-called annealing or recrystalli-zation twins in face-centered-cubic metals continues to be a matter for speculation, and in the present report an attempt is made to explain their origin and to account for at least a majority of the observations concerning their behavior. The fact that annealing twins are prominent only The speelmen was deformed 8 pet in compression and then indented over the lower left-hand corner in a Rockwell in-denter, and then annealed to cause partial recrystallization. Note intense twinning in heavily deformed part and slight twinning in less deformed part. The upper right-hand corner is unrecrystalized. Area reduced approximately 25 pot for reproduction. after recrystallization suggests that deformation may be necessary for their formation. In 1926, Mathewson1 reported the observation by Phillips that annealing twins are frequently parallel to strain markings which delineate octahedral planes in the deformed (and partially recrystallized) matrix, and suggested that strain markings are mechanical twins which grow into annealing twins during recrystallization. Later work by Burke and Barrett' has shown that strain markings are traces of planes upon which slip has occurred, and that there is no evidence for the formation of mechanical twins of microscopically resolvable width in face-centered-cubic metals. Mathewson3 has pointed out, however, that slip may produce twin faults, and later modifications of this hypothesis have assumed that twin faults rather than true mechanical twins serve as the nuclei for annealing twins. Carpenter and Tamura5 suggested, also in 1926, that annealing twins might form by accidents of growth. A close-packed layer of atoms can be added to the octahedral plane of a face-centered-cubic metal in two possible positions, the right position

Jan 1, 1951

THE compiler, or author, of the Probierbücblein is not known, and the date of its first printing is uncertain. It was obviously not written by an assayer who wished to give a coherent description of his craft for the instruction of others; this was left for Biringuccio first to do. It is easy to believe that originally the Probierbücblein was a random collection from various sources of information useful to an assayer, probably gathered by one of the profession for his own use. It must remain a matter of speculation whether this was shown to a printer, who recognized the opportunity to turn an honest penny and made an inept attempt to give the manuscript the appearance of a coherent account by writing a preface and arranging the various items in somewhat logical sequence, or whether the assayer him- self started this job and was prevented from finishing it. That some sections of the book, especially near the be ginning, present an almost continuous story, while others are chaotic in their arrangement; that several paragraphs are printed more than once in different places; that there are paragraph headings, for which the text was never written, or lost, followed by irrelevant information-all this seems evidence of a job unfinished and points to a publisher's offering for the public's quick money. The demand must have been brisk, for metal working was a profitable profession, and the jeweler who was working with metals but did not care to become completely trained in assay methods would jump at the chance of acquiring easy knowledge. Even the great Agricola has whole sections obviously plagiarized from the Probierbücblein. Neither Biringuccio nor Ercker shows any direct influence, though they and all subsequent metallurgists will in some degree be affected by

Jan 1, 1949

R. 8. MACPHERRAN, Milwaukee, Wis. (communication to the Secretary): The importance of carbon in pig-iron, as well as the desirability of buying, for some purposes, irons which are high in carbon, has always been recognized. Mr. Summers, I think, has given undue weight to the carbon-determinations. The combined carbon often decreases materially as the center of the pig is approached, with a corresponding increase in the graphite. Even the determination of total carbon, to be of service, must he supplemented by that of other elements. By it alone, the softness of a foundry-iron cannot be determined. Car-wheels and No. 5 iron, for instance, frequently contain 3.75 per cent. of carbon. This is the percentage specified by Mr. Summers for his No. 1 iron, " with the silicon about anywhere the furnace-man wants it." It is true that, other things being equal, the higher the carbon the softer the iron for foundry-use. But to introduce any given percentages of graphitic and total carbon into a pig-iron specification would but make the specification more complicated, without increasing its value in a commensurate degree. Mr. Summers does not believe in the governing of mixtures by the silicon, and, in support of his views, gives several tables. It seems to me that both his conclusions and his tables are somewhat unsatisfactory. He comments on the irregularity in carbon, but fails to note the significance of the irregularity in silicon..The variation of 0.7 per cent. in silicon, for example, is too great to be accounted for by difference in blast. It might better be attributed to bad grading at the furnace, unsystematic sampling, or irregular charging. Deductions drawn under such conditions are of little value. In ordinary work the castings from the same mixture should

Jan 1, 1899

By John Sullivan

Resources for Freedom, a report by the President's Materials Policy Commission, commonly termed either the Paley report, after its chairman, or the PMPC report, was issued in June 1952. The data collecting and assembly work for its preparation were done in 1951. The statistical base in most cases was 1950. It reviewed our economy and predicted what it will be in 1975.* The bases for the predictions were given. Consideration was given not only to statistical data and trends but also to technological changes taking place and likely to take place in the ensuing 25 years that will affect our economy. The supply of raw materials was studied and predictions made as to the availability of supply and the sources in 1975. One of the industries covered was iron and steel. For the most part the report did not attempt to provide a curve showing annual growth for any industry or commodity. It contrasted 1950 with the probable status in 1975. Interpolation between these dates is difficult and the Commission did not intend that it be used for short interim intervals. It is possible in 1958 to show the actual changes from 1950. The magnitude of the changes illustrates the agreement with some interpolation of the Paley report. Statistical comparisons can be general only because the Commission did not postulate a linear change. A study of the iron and steel industry will show if the general predictions have been realized or if gross errors were made. This paper is concerned with such an analysis. It is concerned with the production and consumption of crude, not fabricated products. It attempts to bring various facets of technical and statistical information on the industry up to date.

Jan 8, 1959