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By J. V. Gluck

In the present paper," as in earlier publications, V1'2"1 the authors present experimentally obtained relations for the free energy of solution of oxygen in various metals as a function of temperature. The relations are linear and given in slope-intercept form. The authors give values for the "probable error" of the slope and intercept, citing Birge's method17 for obtaining these quantities. Birge discussed these methods as early as the period 1929-32.25726 In Ref. 25 the probable error is defined as "the numerical value which the true error is as likely to exceed as not", i.e., 50 pct probability. Ref. 26 is even more detailed and includes a lengthy discussion of the applicability of the Gaussian distribution to experimental data. However, the use of the "probable error" has come under some question. For example, Ezekiel'~ states that "the use of the probable error tends to make the results appear rather more accurate than the standard error". Moroney28 stated (in 1951) that "the term 'probable error' was used in former times to denote 0.67450 (50 pct confidence using the normal distribution)....the term, a poor one, is now very much obsolescent. It has been said that 'it is neither an error nor probable' ". Bennett and Franklin in 1954" in discussing statistical confidence levels mentioned that "the customary use of the 5 and 1 pct levels is not completely a matter of chance; these levels probably represent a balance between the desire to be correct and the desire to be specific. Also in most people's minds the borderline between something that could possibly happen and something that is not likely to happen is somewhere in this region. Certainly 5 or 1 pct confidence limits are to be preferred to limits such as the 'probable error' which has only a 50/50 chance of including the correct value." It may readily be seen that the 95 pct confidence level, which is given by 1.960 (assuming large sample size), thus corresponds to approximately three times the "probable error". Indeed, limits of one standard deviation correspond only to about 68 pct probability. Even if we triple the tolerances given by the authors in the equations of their Table 111, the deviations do not become excessive and would not detract from their excellent results. It could then be said with a high degree of confidence (95%) that the precision of the slope and intercept values is about *3-5 percent of their absolute levels rather than the 1-2 percent implied in Table 111. This is then compatible with an earlier suggestion of Gokcen~' of a probable accuracy of 5 pct in dissolved oxygen measurements by the technique employed. Alternatively, the authors could have

Jan 1, 1967

By P. H. Dudley

THE piping and segregation of ingots of steel is a comprehensive subject, and must be studied in reference to the different grades of soft, medium, and hard steel, rather than to discuss it in a general manner, as though applicable to all grades. Rail steel, however, will receive the most consideration in this paper, for the wheel-loads of the motive pourer and rolling stock have doubled from 1890 to 1910. Steel rails and tires which were efficient under the light loads, became less serviceable under the double wheel-loads, quadrupled tonnage, and higher speeds. Bessemer Steel. Bessemer steel of froth 0.10 to 0.15 per cent. of carbon, for splice-bars, spikes, and tie-plates, rises in setting, and is cast in bottle-mouthed molds, which must be capped to prevent an over-flow from the top. This grade of steel rises in the molds and makes a longer ingot than the volume of molten steel when first teemed. The ingots which are allowed to cool and then cut open, show, particularly in the upper part, large occluded blow-holes, and when they are Dot oxidized or do not contain foreign matter, weld more or less completely when the steel is rolled or forged above 1,100° C., and it :is in this way that the blow-holes are closed it the low-carbon steels.

Jan 4, 1913

By C. H. Mathewson

EXCEPTING the joint sessions on gases in metals held during the day on Tuesday, the Institute of .Metals opened its activities with a division dinner at the Commodore on Tuesday evening, with Sam Tour, retiring chairman, presiding. W. M. Corse, secretary-treasurer, outlined the financial status of the division and stated the investment fund is becoming large enough so that in the near future it will be possible to pay all expenses of a foreign lecturer once in two years and not rely on an extended speaking tour to cover expenses. W. B. Price reported on his attendance at the Zurich, Switzerland, meeting of the International Society of Testing Materials and gave a graphic account of his visit to the Grand Salon, his meeting with Mussolini, and his audience with the Pope. Buffalo was announced as the place of the fall meeting, to be held during the week of Oct. 3.

Jan 1, 1932

By William E. Ford, Edward Salisbury Dana

Secondary Twinning. - When there is reason to believe that the twinning has been produced subsequently to the original formation of the crystal, or crystalline mass, as, for example, by pressure, it is said to be secondary. Thus the calcite grains of a crystalline limestone often show such secondary twinning lamella?. The same are occasionally observed (Ilc, 001) in pyroxene crystals. Further, the polysynthetic twinning of the triclinic feldspars is often secondary in origin. This subject is further discussed on a later page, where it is also explained that in certain cases twinning may be produced artificially in a crystal individual - e.g., in calcite (see Art. 282).

Jan 1, 1922

By David B. Reger

Exploration for new pools of gas in the Oriskany sand and continued exploitation of areas already known to be productive in that sand were the main features of petroleum activity in West Virginia during 1938. To a considerable extent the exploration program resulted in failure, but the extension of former areas was eminently successful. Throughout the state, in general, less drilling was done than in 1937. According to the West Virginia Department of Mines, only 631 permits to drill were issued, as compared to 1034 in 1937. The account of operations, as reported by trade journals and other sources, shows that 766 wells were drilled, resulting in 131 oil wells with 1609 bbl. of daily production; 484 gas wells with 1,232,216,000 cu. ft. of daily open flow; and 151 dry holes. Several discoveries indicate new pools of oil and gas; and several extensions of old gas pools have been made. In spite of a decreased number of total wells, the figures for new gas and oil are both larger than in 1937. The new oil average is 12.3 bbl. per well per day; the gas average is 2,545,900 cu. ft. per well per day, the ratio of dry holes to completions is 19.71 per cent. No general attempt was made to discover new pools of oil. A continued low price, coupled with reduced takings, combined to make drilling unattractive. The principal oil wells completed, by counties are: Boone, 6; Calhoun, 10; Clay, 7; Gilmer, 5; Kanawha, 5; Lincoln, 7; Pleasants, 13; Ritchie, 32; Roane, 6; Tyler, 7; and Wirt, 14. Production for the year, according to the Oil and Gas Journal, was 3,724,750 barrels. The leading counties in gas, with the number of successful wells in each, are: Boone, 16; Braxton, 13; Cabell, 47; Calhoun, 29; Doddridge, 10; Gilmer, 55; Kanawha, 127; Lincoln, 18; Ritchie, 29; Wayne, 19; and Wetzel, 26. Production for the year is estimated as 150,000,000,000 cubic feet. Pipe-line construction, which was extensive in 1937, was insignificant in 1938. Exploration was not as active as in 1937. Field prices of both oil and gas have severely declined.

Jan 1, 1939

By David B. Reger

Exploration for new pools of gas in the Oriskany sand and continued exploitation of areas already known to be productive in that sand were the main features of petroleum activity in West Virginia during 1938. To a considerable extent the exploration program resulted in failure, but the extension of former areas was eminently successful. Throughout the state, in general, less drilling was done than in 1937. According to the West Virginia Department of Mines, only 631 permits to drill were issued, as compared to 1034 in 1937. The account of operations, as reported by trade journals and other sources, shows that 766 wells were drilled, resulting in 131 oil wells with 1609 bbl. of daily production; 484 gas wells with 1,232,216,000 cu. ft. of daily open flow; and 151 dry holes. Several discoveries indicate new pools of oil and gas; and several extensions of old gas pools have been made. In spite of a decreased number of total wells, the figures for new gas and oil are both larger than in 1937. The new oil average is 12.3 bbl. per well per day; the gas average is 2,545,900 cu. ft. per well per day, the ratio of dry holes to completions is 19.71 per cent. No general attempt was made to discover new pools of oil. A continued low price, coupled with reduced takings, combined to make drilling unattractive. The principal oil wells completed, by counties are: Boone, 6; Calhoun, 10; Clay, 7; Gilmer, 5; Kanawha, 5; Lincoln, 7; Pleasants, 13; Ritchie, 32; Roane, 6; Tyler, 7; and Wirt, 14. Production for the year, according to the Oil and Gas Journal, was 3,724,750 barrels. The leading counties in gas, with the number of successful wells in each, are: Boone, 16; Braxton, 13; Cabell, 47; Calhoun, 29; Doddridge, 10; Gilmer, 55; Kanawha, 127; Lincoln, 18; Ritchie, 29; Wayne, 19; and Wetzel, 26. Production for the year is estimated as 150,000,000,000 cubic feet. Pipe-line construction, which was extensive in 1937, was insignificant in 1938. Exploration was not as active as in 1937. Field prices of both oil and gas have severely declined.

Jan 1, 1939

By J. T. Eash, W. S. Crowell, E. M. Wise

The practice of dentistry, particularly the construction of artificial dentures and "bridges," involves a unique and difficult application of the precious-metal alloys. Appliances used in the mouth are continuously exposed to corrosive agencies which can hardly be described as mild, and must remain free from tarnish and be substantially immune to corrosion. Limitations with respect to space and weight demand high physical properties, while complexity of form requires ease of working. The high corrosion resistance required necessitates the use of alloys of high precious metal content. The usual expedient of resorting to mechanical working to produce the requisite strength and stiffness cannot be utilized because of the frequency of annealing and soldering operations. To meet these difficult conditions manufacturers of dental goods were early led, unknowingly perhaps, to the production of precipitation-hardening or temperable alloys. The excellent properties of iridium-platinum may have suggested the addition of platinum metals to the conventional gold-silver-copper alloys to produce greater strength and hardness. It was found that such quarternary alloys retained their high physical properties after passing through the usual soldering process; i. e., heating to 750° to 800" C. and cooling naturally in the air. Later it was discovered that they could be softened and rendered more ductile by heating to the same temperature and quenching in water. These early examples of precipitation hardening, for years the common knowledge of dental practitioners and laboratory technicians, escaped the attention of the scientific world and discovery of the transformation which was responsible for this hardening was disclosed by the Russian investigators of the system Au-Cu, Kurnakow, Schemtschushny and Zasedatelev~,(~)$ although the optimum conditions for securing good properties in aged alloys were not given attention.

Jan 1, 1932

By G. S. Rice

IT is evident from Professor Louis' remarks that he holds a different opinion on certain phenomena connected with a specific type of surface subsidence from mining than is held by many engineers in the United States. The question which appears to be at issue is whether or not the line or plane of "draw" produced in ground movement resulting from extraction of pillars may, under certain conditions, be vertical or even inclined toward the workings rather than inclined for- ward over the unworked mineral, as it is universally agreed occurs in mining by the longwall advancing method. In discussing this case it is well to take the simplest condition, such as specified by Professor Louis, of a flat bed, whether it be coal, iron or other mineral, where the overburden is stratified rock and where there is no overlying quicksand. Professor Louis says in effect that his experience is that the ultimate angle of draw is always positive and inclined 5" to 15" from the perpendicular over the unwrought mineral. My experience under Illinois coal-mining conditions is that .'where longwall advancing is used the draw is always positive as Professor Louis describes it, but that in extracting of panels by withdrawal of pillars, the ground movement is manifested, after the first roof' beam break, by the forming of an unstable dome over the goave. Then subsequently, by the falling of individual slabs from the under side, the dome gets larger and higher until it breaks through to the surface of the rock., Up to this time, arch stresses buttress the rocks above the solid coal or mineral. When, however, after. the dome breaks through and the central hole - #enlarges so the arch is no longer sufficiently supported -the stratified rocks cantilever out .from over the solid unworked mineral and tend to break off in masses triangular in vertical cross-section, until the broken loose material, sliding down against the solid rock, .has such a thrust that it balances the tendency ,for the solid stratified rock to break away and slide toward the excavation.

Jan 1, 1929

Texture Transition in Ordered CuAu, by E. A. Starke, Jr., J. C. Ogle, and C. J. Sparks, Jr., Trans. TMS-AIME, 1969, vol. 245, pp. 169-70. pole figures should have had two parts not one. On the Estimation of Oxygen Absorption by Continuous Molten Metal Streams, by J. Szekely, Trans. TMS-AIME, 1969, vol. 245, pp. 341-44.

Jan 1, 1970

By G. Derge, L. D. Kirkbride

In recent years the problem of sulfur elimination in iron and steel-making has been of increasing importance. This interest has been due to the increasing amounts of sulfur coming into the system via raw materials. As a result, many investigations have been directed at obtaining information pertaining to the rate and mechanism of sulfur removal in the blast furnace as well as measuring appropriate thermodynamic quantities. Chang and Goldmanl as well as others2'3 showed that the process of sulfur transfer from molten carbon-saturated iron to blast furnace-type slags could be considered as two opposing first-order chemical reactions. Recently, Ramachandran et al.4 have shown that during desulfurization electrical neutrality is preserved in both phases and iron and silicon are transferred into the slag concurrently with the evolution of carbon monoxide gas. They concluded that the reaction s + c-+ (0)=(S) + CO(g) does not express the stoichiometry of the sulfur transfer process. As in all previous investigations, these authors studied the process of a net transfer of sulfur from metal to slag across a slag-metal interface. However, no experimental data have previously been obtained for the process of sulfurization. It was the purpose of this study to investigate the sulfurization process, i.e., net transfer of sulfur from slag to metal. EXPERIMENTAL PROCEDURE Apparatus—The equipment used in this investiga-tion was typical of that used by others.1-3The furnace was a high-frequency induction unit powered by a 35 kw Hg spark gap converter. Fig. 1 shows a schematic diagram of the apparatus. A two-compartment crucible assembly was employed to melt the slag and metal charges; being similar to that used by Ramachandran,4 in size and design. The atmosphere was that produced by reaction of hot graphite with air. Temperature measurements were made by W-Mo thermocouples which were calibrated against a Bureau of Standards Pt - Pt 10 pct Rh couple. Temperature control was always good to * 5°C and in general was much better than this figure. Raw materials used in the experiments were C. P. reagent grade where possible. The silica used in the preparation of the slags was in the form of highly purified silica flour. Silicon and titanium additions

Jan 1, 1961

Jan 1, 1967

G. McMEANS*—This paper is a very good demonstration of the use of a new tool for the solution of industrial problems of a physical nature. To have solved this problem without the use of radioactive tracers would have required a far greater amount of investigation and work. The authors have described their work in such detail and in such a manner as to suggest the possibilities of the use of such tracer studies in the solution of many perplexing problems of industry. R. E. BREWER †—The authors are to be congratulated on this very excellent paper, which describes the results obtained by utilizing radioactive tracers in investigating the complicated reactions in the coking process. The paper has especial merit because the study was made under typical operating conditions in a commercial coke oven. Considering all the difficulties involved, the results obtained are excellent. My brief comments will relate primarily to the method used for determining the sulphur in the gas and to the value of the data obtained in stimulating further research. In discussing their results, the authors state (p. 17) that "Of the total sulphur charged to the oven in the coal 95 pct was accounted for in the coke and gas. Most of the sulphur unaccounted for is believed to have been lost in the gas, since the gas sampling system removed all the H2S but probably only part of the organic sulphur compounds present in the gas. Although sulphur in the acid-insoluble tar residue in the gas scrubbing bottles was determined and added to the total sulphur determination of each sample, it is doubtful whether an aliquot portion of tar for each sample was obtained." The reviewer believes that the authors might have obtained a better sulphur balance had they used an improved procedure for determining sulphur in the gas. The absorption train should have included a trap to remove the tar and am-moniacal liquor and a wash bottle containing 5 pct sulphuric acid to remove ammonia in the coke-oven gas before it entered the gas scrubbing bottles containing the ammoniacal cadmium chloride solution. Sulphur in the tar and

Jan 1, 1950

By William T. Folwell

The Lucky Friday mine east of Mullan, Idaho, is an outstanding example of a property in the Coeur d’Alene district where a small and insignificant- appearing silver-lead-zinc vein at the surface has changed at depth into a large vein of great importance. The Lucky Friday vein has little if any surface expression and above the 1200 level the ore shoots are small and discontinuous. Between the 1200 level and 2450 level, the lowest developed level, the main ore shoot has shown remarkable improvement on each succeeding lower level, and today the mine is one of the major lead-silver producers in the Coeur d'Alene district. History: The Lucky Friday property is on the north side of the South Fork of the Coeur d'Alene River in sections 25, 26 and 35, T. 48 N., R. 5 E., Hunter mining district, Shoshone County, Idaho. This is about one mile east of the town of Mullan, which serves the eastern portion of the Coeur d'Alene district. The southern part of the property is crossed by a branch line of the Northern Pacific Ry. and by U. S. Highway 10. This highway is the principal road crossing the panhandle of Idaho and connects the district with Spokane, Wash., on the west and Missoula, Mont., on the east. The main portal and surface plant of the Lucky Friday mine is at an elevation of 3365 ft, only a short distance above the valley floor and a few hundred feet from U. S. Highway 10, so the mine is readily accessible for year-round operation.

Jan 12, 1958

By Robert L. Russell, Henry W. Zimmerman

The Bunker Hill mine in the Coeur d'Alene mining district at Kellogg, Idaho, has been a major producer of Pb-Ag-Zn ores since its discovery in 1887. The mine has produced over 29 million tons of ore from some 20 to 25 veins and ore zones and now covers an area approximately 1 mi long by 0.5 mi wide. The active section of the mine extends from 2500 ft above sea level to 1600 ft below sea level. Ore production is presently at the rate of about 1700 tpd. A 2-mi adit, the Kellogg tunnel, at the 2500 elevation provides access to the main shaft area. Ore is hoisted to the adit level through a 5000-ft. 50º-inclined shaft extending to the lowermost haulage level 1200 ft below sea level. Primary shaft service for men and materials is supplied by three major internal inclined shafts equipped with double-drum hoists. Present production requires ten levels to serve for main line track haulage. These range up to 5000 ft in length and are either 200 or 400 vertical ft apart. Also, many intermediate levels exist throughout the mine.

Jan 1, 1971

By J. B. Clemmer, P. E. Churchward, C. Rampacek

A cyclic method for processing manganese ores using sodium sulphate as the basic reagent is described. Sodium sulphate is electrolyzed in a diaphragm cell to give an anolyte-containing agentisdescribed.Sodiumsulphuric acid and a catholyte-containing iselectrolyzedincaustic soda, a part of which is carbonated in a cyclic manner to form soda ash. The reduced ore is leached with the anolyte to dissolve the manganese and the impurities are precipitated by addition of catholyte. Manganese in the pregnant todissolvethemanganeseandtheimpuritiessolution is precipitated as synthetic rhodochrosite with a carbonated catholyte, and sodium sulphate is regenerated. Calcining the manganese carbonate gives a high grade product and the carbon dioxide is returned to the carbonation step. The results of laboratory tests using cells equipped with synthetic-fiber diaphragms and permselective membranes, which permit transfer of anions or cations during electrolysis, are described. A METHOD which has been considered for pro-cessing manganese ores under emergency conditions to recover a product suitable for smelting to ferromanganese involves reductive roasting of the ore for leaching with dilute sulphuric acid followed by precipitation of the manganese from the purified pregnant solution with sodium carbonate. Although the process is operable and involves no novel or untried steps, it is noncyclic in regard to reagents. Research seemed warranted to determine if a cyclic process could be developed by electrolyzing the sodium sulphate formed during precipitation of the manganese with soda ash to regenerate sulphuric acid and sodium hydroxide. Reduced ore would be leached with acid anolyte to dissolve the manganese. The iron, alumina, and other dissolved impurities would be precipitated with the caustic catholyte, and the manganese in the purified pregnant solution would be precipitated as artificial rhodochrosite with carbonated catholyte to regenerate simultaneously sodium sulphate for electrolysis. Waste boiler gas and CO, from calcining the manganese precipitate would be recycled for carbonation of the caustic catholyte. There is a surprising lack of data in the technical literature on diaphragm electrolysis of sodium sulphate. One of the more comprehensive papers, by Atwell and Fuwa, describes the problem involved in electrolyzing byproduct sodium sulphate from the viscose process with particular regard to the design and operation of asbestos diaphragm cells. Frisk' also investigated electrolysis of sodium sulphate from viscose-spinning baths to recover caustic soda and sulphuric acid. The objective in these investigations was to produce, by electrolysis and evaporation, a concentrated caustic-soda solution and a sulphuric-acid solution low in sodium sulphate. Because of these requirements, the process was not too attractive despite a favorable yield of caustic and acid with a reasonable power consumption. Because strong acid and base are not required for processing manganese ores and nonelectrolyzed sodium sulphate is not objectionable in either reagent, the present problem was somewhat simpler than that of these investigators. The purpose of this report is to summarize briefly the results of laboratory electrolysis of commercial sodium sulphate in diaphragm cells of different types and the application of the acid and caustic for processing manganese ores in a cyclic manner. Electrolysis in Permeable Diaphragm Cells The principal problem in electrolyzing sodium sulphate in a permeable diaphragm cell is to prevent mixing of the acid and base formed in the anode and cathode compartments. It is not enough to separate the anolyte and catholyte by a single diaphragm. A three-compartment cell in which the sodium-sulphate solution is fed to the center compartment and flows through the permeable diaphragms to the anode and cathode compartments is more efficient electrically. Diaphragms should be porous enough to allow flow of solution to outer compartments but tight enough to prevent gross mixing of the anolyte and catholyte. In addition to being resistant to acid and alkali, the diaphragms should offer minimum resistance to the flow of current. It is also important that the electrolyte contain a high concentration of sodium sulphate to furnish an abundance of sodium and sulphate ions and thereby decrease the current carried by hydrogen and hydroxyl ions. A practical limitation of sodium-sulphate concentration is imposed by the decreased solubility of sodium sulphate with decreasing temperature. At 20°C, a concentration of 200 g per liter sodium sulphate can be maintained. Little is gained in conductivity by using a concentration greater than 200 g per liter. The small-scale continuous electrolysis tests were made in a 12x12 in. open-top bakelite cell equipped

Jan 1, 1956

By M. G. F. Söhnlein

In the earlier clays, these ores were treated by chloridizing-roasting followed by amalgamation, with satisfactory results, according to the information now available. Material from old tailing dumps from ore treated by this process, which are found at several places in the vicinity of Oruro, seldom contains more than 5 to 6 oz. of silver per ton. As ore with less than 100 oz. per ton was not treated, the extraction of silver must have been good. Reports of the operating companies published about 1890 asserted that over 90 per cent. of the silver was recovered, but in these calculations, as a rule, no allowance was made for silver lost during roasting and the figure referred only to the extraction of silvcr by amalgamation from the roasted ore.

Jan 1, 1921

By AIME AIME

THE session on milling methods on Monday afternoon.* with G. H. Clevenger, chairman of the Mining Methods Committee presiding, was well attended. However, none of the authors of the papers presented were present except Messrs. Taggart and Ince. The paper on "Elements of Operations of the Pneu¬matic Table," by Messrs. Taggart and. Lechmere-Oertel, was presented by Professor Taggart as was the paper on "Calculations in Ore Dressing," by Luyken and Bierbrauer, due to the absence of the authors.

Jan 1, 1929

By AIME AIME

MANY of the important papers to be presented at the World Congress of Engineering at Tokyo, in November, 1929, are being furnished by members of A.I.M.E. and a list of them is given below: "Fifty Years of Physical Metallurgy,,-by H. M. Boylston, Case School of Applied Science, Cleveland, Ohio.

Jan 1, 1929

By J. S. Miller

This paper describes the method of mining a steeply pitching anthracite seam on a heavy pitch in the Orchard vein in No. 1 Tunnel of the Lehigh Coal and Navigation Co. The Orchard vein in the Neaquehoning district has a thickness of about 15 ft. on the level of the gangway, which is sufficient thickness for the gangway to be driven full width in coal. Above the gangway, the vein becomes thinner and near the surface is about 8 it. thick. The coal is of good hard quality and carries a fairly good roof. The pitch of the vein is between 65" and 70". Usually the breast-and-pillar method has been employed in the mining of the steeply pitching veins in this section. This method produced good results as far as the mining of the breast was concerned but the recovery of the pillar was difficult as to full extraction and expensive as regards costs. To recover these pillars after the breasts were driven, three methods were commonly employed; they were known as the pillar-breast method, pillar-skipping method, and pillar-chute method. The pillar-breast method consisted in putting a battery in one corner of the pillar (Fig. I), coupling the manways A and B of the two adjacent breasts for two or three lengths ahead of the working face of the pillar being cut, and working the pillar as a breast. This method was used by the more skilled miners of the earlier days but has practically been abandoned. A slight variation of this method is used to some extent. In this case, the pillars are left wider than ordinarily and of sufficient width for the full-width breast to be driven in and a small pillar left on each side of the pillar breast between it and the regular breasts. With the completion of the "pillar breast," the ribs are drilled full of holes, loaded, and fired. In the pillar-skipping method (Fig. 2), the middle breast of three is not driven through and is drawn empty while the outside and inside breasts are kept full. At the corners of the two pillars standing, batteries are put in and a skip of the two pillars started; the coal in the two pillars is blasted over into the empty breast. A small pillar is kept along the

Jan 1, 1925