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From the early part of the thirteenth century bituminous coal was called "sea coal" in England, from the fact that the coal seams in the Fife and Northumberland fields outcropped on the shores of the North Sea and wave action and erosion resulted in lumps of coal being found in large quantities along the shores. These were gathered by women and children and sold for fuel to replace wood. Coal first reached London by sea, and there was a "Secole Lane" in that city in 1228. The term was gradually applied to all coal and for some hundreds of years all coal in England was called "sea coal", and the term is not yet obsolete there. Another reason for the use of a defining word was the fact that from time immemorial, in England and elsewhere, the word coal meant char-coal, or coal made from wood, as this was the common fuel of those times when anything other than natural wood was burned. The biblical references to coal all mean wood-coals or charcoal, and one must be careful in writings prior to at least 1750, when "coal" is used to be sure that it means stone, or mineral coal, rather than wood or charcoal. "Sea-coal" was in common use along the Atlantic seaboard until after about 1780; the first map showing coal in Pennsylvania, Ohip and Kentucky, made as of 1750, used the term "sea-coal here."2 In the interior stone coal was used by the early writers almost entirely, partly to differentiate it from charcoal, but largely because it was found with stones and rocks, and in most places then had the same value. "Fossil" coal was used by Hamilton in 1790. Jefferson called it mineral coal and pit coal in 1781. The term mineral coal was usually used in the governmental references to it as late as 1850, but the present use of bituminous coal began as soon as anthracite came on the market in 1820. Both mineral and stone coal still survive in the laws of several states specifying the weight of a bushel of coal.

Jan 1, 1942

By Allan J. Clark, W. J. Sharwood

When the cyanide process came into general use, late in the nineteenth century, chlorination was quickly supplanted, but amalgamation yielded place more slowly, being still the major process at many plants, where it is followed by cyanidation of the tailings. The research work of the Denny brothers in South Africa' was probably the most important contribution of its time to the metallurgy of gold. By grading analyses of mill products, they pointed to the necessity of fine grinding to accomplish maximum extraction by cyanide. The work here described is merely an extension of the Dennys' method. Developing the fine-grinding principle, the steps of "crushing in solution" and of "all-sliming" were logical sequels, though both had been attempted early in the history of the cyanide process. Crushing in solution introduced certain complications in amalgamation; when "all-sliming " was adopted it was observed that the omission of amalgamation did not materially affect the total recovery. Thus the field of the older process has become much restricted, being at present confined to ores which, yielding freely to amalgamation, either are too low in grade to show an economic advantage in "all-sliming," or present chemical or other difficulties making the use of cyanide solution unadvisable during the crushing and preparation of the ore. South African ores are typical of the former class; Homestake ores are of both classes, but even in these instances the amalgamation work is being curtailed and greater burdens thrown on the cyanide plants. It is obvious that the time required for the dissolution of gold depends on the size of its particles. In an effort to determine the critical size, the following laboratory method was evolved. A standard amalgamation test2 had already been established, which involves the agitation of about 100 gm. of ore with 20 gm. of pure mercury, the latter then being separated and its gold contents determined. This method was applied directly to certain mill products with interesting results, a few of which may be noted here. The column "Free Gold" gives the value per ton thus amalgamated, as against the " Total Gold " determined by fire assay.

Jan 1, 1923

By J. M. Ohm, C. M. Bunker

Two special tools for recovering gamma-ray probes and logging cable from drillholes have been designed by Ohm and Bunker and constructed by Ohm. Though intended specifically for U. S. Geological Survey equipment, they may be used with other equipment of the same general type. Fishing Tool for Probes: A fishing tool of the overshot type (Fig. 1) was designed to retrieve logging probes (sondes) that become disconnected from the logging cable and are trapped in the drillhole. When the tool slides over the top of the gamma-ray probe, studs on the bottom engage the shoulder near the top of the probe (Fig. 2), which is then pulled to surface. The barrel can be constructed from brass or steel tubing. Wall thickness is not a critical dimension, but the tool should be heavy enough to sink through mud or water in the drillhole. The internal length of the tool must be enough to prevent interference with the upper end of the probe head as the tool slides over it. The design of the probe head used by the USGS required a minimum free space of 2 1/2 in. inside the fishing tool, which was made 7 1/2 in. long to increase the weight. The lower end, which engages the shoulder of the upper end of the probe, contains three studs placed at 120" around the circumference of the tool and held in the engaging position by the tension of a spring wire. The studs can be made of any metal, such as steel, having high tensile strength. As the tool slides over the probe the studs are pushed outward from the center against the spring tension, allowing the tool to slide into position below the shoulder of the probe head. The spring tension forces the studs inward into the engaged position after they pass the shoulder. When the tool is raised the studs stop against the shoulder, preventing the tool from sliding up over the top of the probe. Once it engages the shoulder of the probe it cannot be freed until both probe and fishing equipment are recovered from the drillhole.

Jan 1, 1960

By S. J. Sindeband

J. WULFF*—It seems to me that the author could improve the quality of his high temperature material by using less nickel as a cementing agent in hot pressing. Furthermore, to avoid the presence of undilfused nickel which would not be oxidation resistant, permit me to suggest that he use a nickel-chromium powder containing a small percentage of boron. This would give him a liquid phase at a lower temperature and accelerate both sintering and homogenization. The commercial alloy known ascolrnonoy contains sufficient chromium to be heat resistant and sufficient boron to be of low melting point. Such an alloy may be applicable as a cementing agent in increasing the quality of Mr. Sindeband's alloys. Finally 1 believe the author unfair to himself in expecting a porous material to have properties equivalent to one of 100 pet density. S. J. SINDEBAND—Dr. Wulff's point is well taken. Early in the program we realized the fact that we were having difficulty with these low-melting alloys, and we had hoped, since the colmonoy alloys of which you speak are at the nickel-rich end of the diagram, that by going to the other end of the diagram (chromium boride-rich) we would not have this difficulty. Thus we tried to use very small percentages of binder; but for reasons which are not exactly apparent we found that when we did this it was necessary to raise the pressing temperature to a point which we were unable to attain. For all compositions which we tried using nickel, or for that matter any nickel iron or cobalt containing material as a binder, we found that we would get low melting boride phases, which as you point out are the commercial "strength" of the hard-facing materials. 1 personally believe these owe a great deal of their behavior and even hardness to the nickel boride which is considerable evidence when an alloy of chromium boride is made with nickel. Nickel boride itself is very hard. We did try pure chromium as a binder and found there was considerable difficulty in handling it, particularly since we could not just hot press under

Jan 1, 1950

F. JOHNSON,* Birmingham, England (written discussion t).--. Mr. Skowronski's first melting experiments tend to show that ingots with a "level set" may be obtained without oxygen. Now it is characteristic of all metals which occupy a smaller volume when solid than they do when molten to "pipe." In vertical-cast ingots, this pipe resembles a horn-shaped cavity, with the wide mouth uppermost. In horizontal-cast ingots, the pipe is a longitudinal furrow along the center-line of the ingot surface. If copper be successfully deoxidized and degasified, this furrow will inevitably be produced. In the author's oxygen-free ingots, it is. clear that gases were occluded and these gases effectively opposed the formation of a pipe or furrow by shrinkage (fluid contraction). It is riot a special property of any particular gas which produces this effect. Hence it is not surprising that the author has succeeded in producing level and overpoled ingots through the agency of sulphur. dioxide gas. That he has counteracted the overpoling influence of sulphur by means of oxygen is somewhat difficult to explain, since the well known reaction between cuprous sulphide and cuprous oxide should result in the production of sulphur dioxide gas. Why the presence of excess cuprous oxide should neutralize the overpoling influence of this gas without eliminating sulphur is not at all clear. It is to be regretted that the oxygen was not determined in the bars given in Tables 3 and 4. It is by no means established that sulphur is responsible for the over, poling of ingots given in Table 4, since carbon was used for overpoling. If, however, the same kind of poling treatment was given as that applied in the case of ingots in Table 1, the responsibility of sulphur assumes more definite shape. The author rightly points out that Mr. Johnson's theory of the equilibrium between gases and cuprous oxide does not explain why a simple addition of cuprous oxide does not correct an overpoled charge. Such a charge must be re-worked to "set" copper. This re-working (rabbling) undoubtedly forcibly removes the excess gases, which are not removable by cuprous oxide.

Jan 11, 1918

By Roy A. Hardy

The Getchell mine is a comparatively recent discovery in the old Potosi mining district, Humboldt County, Nevada, a district organized in the seventies and eighties, in which some prospecting was done in several metamorphic zones along a monzonite-sedimentary contact. The district had no production in the early days and no further work was done until the same metamorphic zones were prospected for tungsten (scheelite) in 1917 and 1918, when a few small lots were shipped. It again lay dormant until 1934, when prospectors investigated a large siliceous escarpment at one end of the old district where outcroppings were a prominent feature of the topography. Undoubtedly, during the early prospecting of the district, the outcroppings had been investigated for mineral, probably by panning, with negligible results because the gold later found is invisible in the concentrate and is refractory. A fire assay revealed the presence of sufficient gold to warrant development work. The outcroppings were easily prospected by short tunnels having their portals in the siliceous material on the hanging-wall side, with a maximum distance to crosscut to the footwall of 135 ft., or a distance at right angle to dip of 60 to 90 ft. Development work, reaching a depth of over 600 ft. on the dip of the vein, was done by means of various crosscut tunnels, winzes and laterals. A churn-drill hole was also sunk, which intersected. the vein at a depth of 1100 ft. on the dip. Sufficient development work of this character was completed by 1937 to justify the erection of a reduction plant to roast the sulphide ore and cyanide the calcine, and to treat the oxidized ore by straight cyanidation, to make a doré bullion for shipment to the mint. The erection of the plant was started that year and finished early in 1938; with a combined capacity of about 800 tons per day. It has operated continuously since erection and recently was enlarged to handle 1000 tons per day. The vein dips with the slope of the mountain, and by stripping the hanging wall the ore may be mined by power shovel for several hundred feet below the outcrop. Thereafter underground methods will be necessary.

Jan 1, 1941

By H. A. Gardner

THE principal use of barium sulphate is as an inert paint pigment.. For this purpose, the ground material is used both in its natural and in its artificial forms. Probably the largest amount is used in the production of a chemically precipitated pigment called lithopone which consists of 70 parts of barium sulphate and 30 parts of zinc sulphide. An enormous tonnage-of this pigment is at the present time being used in the manufacture of interior flat wall paints of the oil type, such paints having almost entirely supplanted the use of corroded white lead which was at one time used for interior painting. The more dense nature, lower price and sanitary value of lithopone was responsible for this change. Lithopone is, moreover, used to a large extent in the manufacture of oil cloth, shade cloth and linoleum. Its whiteness makes it of particular value for this purpose. Barium sulphate is also used of itself in admixture with other pigments in the manufacture of prepared paints. The chemically precipitated form of barium sulphate, which is generally called blanc fixe, is also used for this purpose. Much controversy has raged in the paint world over the question of inert pigments such as barytes, silica, asbestine and china clay. These pigments are probably called inert because they have no chemical action upon the linseed oil in which they are ground to produce paints, and on account of the fact that they become transparent in oil. It is well known that in the manufacture of paints, opaque white pigments, such as basic carbonate white lead, basic sulphate white lead, zinc oxide etc., are generally used as the grinding base. These base pigments, when ground in oil, react therewith to some slight extent, and they produce white paints which have excellent biding or obscuring value. The inert pigments so-called, when ground in oil and spread out into a thin film, form transparent coatings which have no hiding power. It has been contended, therefore, that the use of barytes or similar inert pigments in paints is resorted to simply for the purpose of cheapening the cost of the product.

Jan 9, 1914

By S. R. Elliott

THE principles of the caving system, as they apply to mining of soft iron-ore deposits, are well known, as this method has been in use for many years. It is, however, necessary to give a general description of it before describing the Athens method. The shaft and surface equipment should be placed at a sufficient distance from the orebody, so that the caving and pulling of the surface will not disturb the operations of the mine. Levels are started at the proper intervals, and when raises are completed, slicing commences at the top of the orebody and progresses downward. The necessary precautions are taken to avoid the occurrence of large open rooms and it is customary to break sufficient capping to form a mat to prevent heavy falls of ground from crushing through to the lower sublevels and endangering the lives of the workmen. Slicing is continued, and when sufficient width and length are undercut, the capping commences to cave, and in time a settlement occurs at the surface. As soon as this caving commences, the pressure on the timber naturally increases; after it extends to the surface, the amount of pressure has a certain relation to the depth. In other words, the pressure increases with the depth, but not in direct proportion. At great depths, such as that found at the Athens, 2500 ft. (760 m.), the pressure might be so excessive that the cost of keeping working places open would be prohibitive. The actual caving of the surface in a deep mine, with a great thickness of capping, is slow and often takes years to accomplish. After sufficient width and depth -have been undercut, the capping starts to break away, but through arching large masses of rock-.fill the opening, support the capping, and retard the continuation of caving. Caving to the surface is, therefore, retarded until either a sufficient thickness of the orebody is removed, or the width and length of the undercut part have been greatly increased. I wish to emphasize this fact of slow caving, for it is on, this principle that the success of the Athens system. largely depends.

Jan 8, 1920

F. WEIMER,* Washington, D. C. (written discussiont).-For electrical measuring instruments, especially those types that involve the Wheat-stone bridge or potentiometer principle and standards of electrical resist-ance, there has been, for a considerable time, a need for better resistance materials. For a satisfactory resistance material, much depends on the purposes for which it is to be used. For potentiometers and Wheatstone bridges, such as are in more or less general use, and the more common forms of resistance standards, a good quality of manganin answers fairly well. However, it should not be presumed that manganin is considered ideal for the purpose, for in measuring instruments and resistance stand-ards, there is still much to be desired. An experience of more than 10 years in the study of the resistance standards and resistance apparatus shows that manganin resistances change with time in a way that is very annoying and the maintenance of the unit of resistance to the desired accuracy requires an excessive amount of work or may be said to be prac-tically impossible. The changes in resistance are generally most rapid and erratic in resistances of very low and very high values. In resist-ances of low value, the resistance material is often in the form of thin sheets so that the surface is large and usually more or less unprotected from the atmosphere, or the oil in. the case of oil-immersed standards. In resistances of high value, the resistance material is in the form of fine wire and, therefore, the surface is large compared with the cross-section. In resistances of medium value, the surface is less, compared with the cross-section, or better protected, usually by a silk wrapping impregnated with shellac. This suggests that one of the difficulties with manganin is slow surface action or oxidation, even when an effort has been made to protect the surface from such action However, the changes observed cannot all be accounted for on this basis. There are, presumably, also some internal changes in the resistance material even when it has been annealed. Further; the changes in manganin resistances seem to be more or less independent of its electrical properties. In other respects, too, manganin is not ideal.

Jan 11, 1919

JOSEPH DANIELS, Seattle; Wash. (communication to the Secretary*). Mine models are of great value to the student and to the layman in visualizing underground conditions, and, in a measure, should be just as much a part of the equipment of a mining school as sets of ore specimens, catalogs, or drawings. The chief drawback, as Professor Stock has indicated, is the time and cost of making them. The greatest good in the development of the model comes to the person who makes it, and I have often wondered whether it might not be possible to have each student make one model during his undergraduate career. At the University of Washington we have been collecting sets of mine timbers, made of 6 by 6-in. lumber, illustrating shaft, level, and stope timbering. This work has been done by freshmen. Perhaps each educational institution could specialize in the creation of a certain type of model and exchange its product for that of another school, just as we now do with ore collections. In this way we could build up good museums at a relatively low cost. JOHN R. CHAMBERLIN, New York, N. Y. (communication to the Secretary?).-The type of model described by Professor Stoek is admirably suited to exhibits of coal mining in horizontal veins, and fulfills perfectly the three purposes mentioned. As an educational illustration in colleges, especially when the students themselves build the model under the direction of their instructors, it is of the highest value; and as each condition in mining requires special methods to depict properly in a model, the student is compelled to exercise considerable inventive resource to construct a true representation, stimulating the imagination and interest in his subject. Models built for exhibits in lawsuits are usually constructed to show prominently some particular feature of vein formation or geology, or the relation of underground workings to surface property lines, and as such their use is invaluable to the successful litigant. When the litigation is ended, it is natural that the model should be relegated to the basement and frequently destroyed, as data on underground workings are often considered of a private character by the operators; and it is

Jan 10, 1917

By George W. Sheary

Situated 45 miles west of Philadelphia and 50 miles southwest of Bethlehem Steel Company's Bethlehem plant, the integrated Grace mine facilities produce 4000 tpd of high-quality iron ore pellets. Startup of the Grace mill was in November 1958, and iron concentrates were shipped until March 1960, when the pellet plant went into operation. The underground mine, when fully developed, will hoist about 9000 tpd, including development rock. The crude ore, which has an iron content of approximately 42%, is magnetically cobbed and crushed in closed circuit with 3/4-in. slotted vibrating screens. The ore is washed and screened in the mill and the plus 1/4 in. screen product is again cobbed prior to feeding to the rod mills. Grinding is done in rod mills, and in ball mills that are in closed circuit with 30 in, cyclones, to 1% on 100 mesh and 65% minus 325 mesh. The ground ore is magnetically concentrated by three-drum permanent type finisher magnets to 67% Fe. The magnetite concentrate is pumped from the mill to a 50 ft thickener in the pellet plant. The thickened magnetite concentrate is relayed to the filters through a two-stage pump arrangement. The filter cake is fed by belt from filter concentrate bins to mixer-muller belts where it is intimately mixed with bentonite and a slight amount of water for moisture control. The fluffed concentrate then drops into balling cones. The green pellets from the balling cones are fed in a prescribed feed pattern to shaft furnaces through the use of shuttle car mechanisms. The green pellets are dried, heated to 2500°F and cooled to 1200°F as they descend through the furnace and into pellet coolers where the pellets are further reduced in temperature to 250°F. Heat is recovered in the cooling process through the use of air-to-air heat exchangers. The cooled pellets discharge on a rubber conveyor belt and are transferred to 6000-ton pellet railroad loading bin. The final pellet product consists of 90% plus 1/4 in. material (after tumble testing1) and contains 66% Fe plus 3% silica.

Jan 5, 1962

By M. Gensamer

IT has been suggested by a number of people that it would be worth while for some one to attempt to summarize or condense the proceedings of this symposium. This task has fallen to me as organizer and co-chairman. Its difficulty will be appreciated by anyone who attempts to read the whole proceedings. It is therefore with trepidation that I offer the following digest. In recent years there has been a renewal of interest in America on this subject of the cohesive strength of materials, and a growing appreciation of the need for a better theory of cohesion failure. The theories of elastic action and plastic action are well developed, particularly the former. The theory of plastic action is still in the course of development, but it is well along. Plastic action is terminated by cohesion failure and what is needed is a theory that will tell us when to expect the cohesion failure. In the past it has generally been assumed that cohesion failure will occur when a critical value of the maximum tensile stress has been reached. Many experiments have shown that this is not strictly true, and this symposium concerns itself with the failures of this simple hypothesis, and with the efforts that have been made to devise a more satisfactory theory. The most active contributor in recent years to knowledge in this field is Dr. McAdam, and he was asked to open the symposium with a summary or condensation of his papers and views. Undoubtedly it is presumptuous to attempt a still greater condensation, but perhaps it will be useful, because even his contribution to this symposium contains no summary, no concise statement of just what his contribution has bees. Dr. McAdam makes two main points. The first is that the cohesive strength is not a single valued quantity, but that it is a function of all three principal stresses and hence must be represented diagrammatically by a surface in a three-dimensional figure. Dr. McAdam has attempted so to delineate the cohesion limit, basing his

Jan 1, 1944

By John W. 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. It is self-evident that a ton of ore near the surface or exposed by present workings is worth much more than a ton buried so far down in the earth that it cannot be removed for many years. If no improvements in mining methods were expected, the value of deeply buried ore would be further reduced by the greater expense that would be required to

Jan 1, 1922

By W. O. Hotchkiss

IN CONSIDERING the question of mining methods the possible rate of production deserves much more attention than it often receives. Hoover's theorem that, in order to show the greatest profit, an orebody should be worked out in the shortest practicable time, should be better known. The author recently' obtained detailed statements of costs from iron-mine superintendents of the Lake Superior district. In discussing these, the effect of rate of mining on cost of production was considered and detailed estimates were made. The methods by which these estimates were made and the way in which they were presented are here described to illustrate the importance of this factor in mining operations. The saving due to lower costs is not the only factor that should be considered. The greater profit per ton is of much importance but of equal importance are the greater profit per ton that will be made on a greater number of tons per year, and the fact that the total profit will be received in a shorter; period. This last makes a great difference in the present value of a property, by shortening the period of discount on future profits. Another item of importance to those operating a number of mines is that the tonnage needed to supply the market can be obtained most profitably by operating the smallest number of mines that will supply the amount required when each is worked to maximum capacity. In the Lake Superior iron district there are many grades of ore, and the requirements for each are known. If the demand for a certain grade can be supplied from mines now operating, the development and mining of a new orebody of the same grade must result in lower rates of production and lower profits to all mines producing this grade. If a company is mining the same grade of ore from three mines when it can supply its needs by operating only two, by operating only two it can obtain the greatest profit. Royalty rates, lease terms, and other considerations modify this general statement, but if all three properties

Jan 5, 1922

By C. Hertzler

The difference of means of milling characteristics by rock and ore type is tested in a statistical manner in the paper. The null hypothesis being tested is that the sample means of two different populations are equal. It is assumed that the null hypothesis is true when performing the test. Because of this, acceptance of this hypothesis leads to the conclusion that the sample means of the two different populations are equal (or there is no significant difference between the sample means), not that the samples come from the same population, as the author asserts. Rejection of the null hypothesis leads to the conclusion that the sample means of the two different populations are not equal. A P value for this test is reported in Table 2 and is incorrectly identified as the probability that the two samples came from different populations. Actually, what was recorded was 100(1 - p) where p is the usual p-value. The usual p-value measures, on a scale of zero to one, the extent to which the data agree with the null hypothesis. It is the probability of observi" a value of the test statistic (Z score) that is at least as contradictory to the null hypothesis as the one computed from the sample data (McClave and Dietrich 11, 1982). The author makes no mention of the fact that were these tests to be conducted together, the chances of determining that the null hypothesis is not true when it is really true are increased considerably (Snedecor and Cochran, 1980). This is a multiple comparisons problem and should be dealt with accordingly. The usual methods involve adjusting the level of the individual tests. Table 2 reports an incorrect 100(1 - p) value in the comparison of concentrate grades for other rock types with .30 to .69% Cu vs other rock types with .70 + % Cu; 86% should be 98.6%. Although the article can be criticized for poor data presentation and discussion of that data, the point the author makes regarding the use of these statistics in the ore reserve estimation process is well taken. It does not appear that inaccuracies in the statistical interpretations have hindered that usefulness.

Jan 1, 1985

By Eugene Guccione

Evidence that the United States is gradually converting to the metric system of measurement can be perceived today even by housewives in a supermarket. The question is no longer whether but when the country will have completed the conversion. To the extent that any bickering about metrication still exists, the debate now centers on such issues as finding agreement on details of implementation, and whether federal legislation should speed up the metric-conversion process or allow it to proceed along its present evolutionary and voluntary course. Apparently, the voluntary or "make-haste-slowly" approach is gaining widespread support. According to The Research Institute of America, Inc., if and when federal legislation is enacted it will likely include the following national ground rules: (1) A National Metric Conversion Board will develop and submit to the President and Congress a comprehensive plan to achieve a coordinated, minimum-cost changeover. (2) The change- over will be completed 8 to 10 years after the board's plan goes into effect, and by that time the US will be predominantly, though not exclusively, metric. (3) Costs will "lie where they fall"; subsidies, special tax concessions, and antitrust exemptions will not be authorized by the legislation. (4) The changeover will be voluntary because of the recognition that while some firms can "go metric" in a matter of weeks, others may require 15 years or more, and a few might never convert. (5) In determining whether or not to convert, on an individual company basis, adherence will be to the "rule of reason-that is, ". . . do not convert unless the engineering, economic, or other benefits outweigh any metric-related disadvantages. No one is talking about rip- ping up our railroad tracks or rewiring our homes just to conform to the practice of metric nations in Europe." (6) Government is to be part of the solution, not part of the problem; in effect, says The Research Institute of America, the leverage of federal procurement will not be exerted to force-feed the metric changeover but will be coordinated with the sector-by-sector conversion of the economy.*

Jan 12, 1975

By N. J. Grant, W. R. Opie

THE amount of hydrogen that will dissolve in lead has been considered negligible. However, a limited number of measurements made recently using apparatus built for determining hydrogen solubility in aluminum alloys' indicate that liquid lead will hold a small but appreciable amount of hydrogen in solution. The apparatus used was similar to that developed by Sieverts.' This consists of a bulb to hold the molten metal, a gas burette for introducing a measured quantity of gas into the bulb and a manometer for measuring the gas pressure in the bulb. Measurements are made by introducing enough of an insoluble gas (helium) to fill the system at a given temperature and pressure, thereby determining the hot volume of the bulb. This gas then is pumped out and hydrogen is introduced until the same pressure is reached, the metal being maintained at the same temperature while in contact with each gas. The difference between the volumes corrected for pressure is then the hydrogen solubility. A more detailed account of the procedure can be found in refs. 1 and 2. The lead was melted in an alundum crucible by induction heating to provide uniform temperature and an important stirring effect. The metal was the purest obtainable, 99.999 + , prepared especially by the research department of the American Smelting and Refining Co. Measurements were made by approaching the equilibrium value from high and low temperatures during the constant pressure runs, and from high and low pressures when the temperature was held constant. Thus a number of measurements were made on each of two large samples which weighed 336 and 398 g. The gases were purified as .described in ref. 1. The effect of temperature on the solubility was studied with the pressure held constant at 760 mm of Hg. To show the effect of pressure, solubility measurements were taken at two constant temperatures, 600" and 900°C. Results The effect of temperature on hydrogen solubility is shown in Fig. 1. The curve representing the data is parabolic, as are plots of hydrogen solubility vs. temperature for other metals and alloys (aluminum,' copper," and iron,& for example). Fig. 2 shows the relationship that exists when the solubility is

Jan 1, 1952

By Thomas Read

READJUSTMENT Of the industrial world to a peace .basis after more than 4 years of war will involve many fundamental and far-reaching changes that cannot as yet he clearly foreseen or definitely provided for. Such problems may be subdivided, in the vocabulary of war, into those involving material and those centering about personnel. Of the two, the-latter group is the more difficult and obscure, as the factors involved are less clearly understood and the methods to be followed are not yet tested and standardized. When it is said that the market is weak, stocks large, and demand light, every business man understands clearly what is meant and. what course he should adopt to adjust himself, so far as possible, to such conditions. But when it is said that the rapid spread of Bolshevism in Europe is a danger to industrial organization in this country, it is difficult to have any assured sense that all that the statement may mean is clearly understood or that the means to be followed to meet such a situation are definitely known. Since Bolshevism is primarily a mental phenomenon and since the rupture it brings about in industrial organization should be prevented, if possible, it is my purpose to restrict this discussion of the activities of the Committee on Industrial Organization to some of its mental aspects, as the chairmen of the sub-committees, from their special knowledge of their own fields, can best set forth recent progress in the lines with which they are especially concerned. The first requisites of success in industrial organization, as in the biological organism of which it is the social counterpart, are unity of purpose and coordinated activity. Typical good and bad examples of this are the relative parts that the United States and Russia have played in the great war. These two factors are primarily mental, and it is not difficult to view the mental aspects of all problems of industrial organization as the most important ones. Unless we can attain unity of purpose and coordinated activity in industry, the provision of comfortable homes at reasonable rent, the assurance of steady work at good wages, the

Jan 2, 1919

By M. Gensamer

It has been suggested by a number of people that it would be worth while for some one to attempt to summarize or condense the proceedings of this symposium. This task has fallen to me as organizer and co-chairman. Its difficulty will be appreciated by anyone who attempts to read the whole proceedings. It is therefore with trepidation that I offer the following digest. In recent years there has been a renewal of interest in America on this subject of the cohesive strength of materials, and a growing appreciation of the need for a better theory of cohesion failure. The theories of elastic action and plastic action are well developed, particularly the former. The theory of plastic action is still in the course of development, but it is well along. Plastic action is terminated by cohesion failure and what is needed is a theory that will tell us when to expect the cohesion failure. In the past it has generally been assumed that cohesion failure will occur when a critical value of the maximum tensile stress has been reached. Many experiments have shown that this is not strictly true, and this symposium concerns itself with the failures of this simple hypothesis, and with the efforts that have been made to devise a more satisfactory theory. The most active contributor in recent years to knowledge in this field is Dr. McAdam, and he was asked to open the symposium with a summary or condensation of his papers and views. Undoubtedly it is presumptuous to attempt a still greater condensation, but perhaps it will be useful, because even his contribution to this symposium contains no summary, no concise statement of just what his contribution has been. Dr. McAdam makes two main points The first is that the cohesive strength is not a single valued quantity, but that it is a function of all three principal stresses and hence must be represented diagrammati-cally by a surface in a three-dimensional figure, Dr. McAdam has attempted so to delineate the cohesion limit, basing his

Jan 1, 1945

By J. A. Goebel, S. Rosen

IN the NiAl phase diagram the NiAl (CsC1-type) phase field extends over a large composition range. At elevated temperatures the nickel-rich phase boundary extends to a composition of about 70 at. pct Ni, a value which is within 5 at. pct of the Ni3A1 (Cu 3 Au-type) phase boundary.' At room temperature, however, the maximum nickel content is only about 60 at. pct. Experiments have shown that alloys containing greater than 63 at. pct Ni when quenched from temperatures below 1000°C contain the equilibrium phases NiAl and Ni3A1. On the other hand, when these same alloys are quenched from temperatures above 1000°C and examined microscopically, a typically martensitic decomposition product appears in the microstructure as shown in the micrograph of Fig. 1. The structure of the martensitic phase has been determined by employing powder X-ray diffraction techniques to be an "ordered" AuCu type (Strukturbericht Llo, space group P/4 mmm - DL). The diffraction pattern of this phase differs from that of AuCu in the appearance of superlattice lines. The structure is shown in Fig. 2. The open circles represent nickel atoms and the half-shaded circles represent nickel and aluminum atoms which are randomly distributed. The sites represented by half-shaded circles would be occupied solely by nickel atoms at a stoichiometry of Ni3A1. The alloys used in this investigation were prepared from 99.99 wt pct Al and 99.99 wt pct Ni by arc melting charges of varying compositions in a water-cooled copper hearth using a tungsten electrode in a gettered argon atmosphere. In all cases chemical analysis agreed within $ at. pct with the nominal compositions of the alloys. Annealing treatments were carried out in a vertical resistance furnace through which a stream of argon gas was flowing. Specimens, which were wrapped in tantalum foil, were quenched by allowing the specimens to drop into a bucket containing iced brine. X-ray diffraction patterns were obtained from -325 mesh powder specimens by using a 114.8-mm

Jan 1, 1969