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By executive order of the President, dated June 25, 1918, the investigation of matters relating to gas warfare, which had been initiated by the Director of the U. S. Bureau of Mines early in 1917, and had been continuously maintained and improved since, that time, was transferred to the recently created Division of Gas Warfare of the War Department. On the occasion of this transfer, both the President and the Secretary of War took occasion to speak most highly of the efficient service that had been rendered by the Bureau of Mines. It gives us great pleasure to reproduce here a letter from the President and from the Secretary of War, bearing on this subject and also to append a brief review of the work of the Bureau of Mines, prepared by its Director, Mr. Van H. Manning. The White House, Washington. June 26, 1918. MY DEAR MR. MANNING: I have had before me for some days the-question presented by the Secretary of War involving the transfer of the chemical section established by you at the American University from the Bureau of Mines to the newly organized Division-of Gas Warfare in which the War Department is now concentrating all the various facilities for offensive and defensive gas operations. I am satisfied that a more efficient organization can he effected by having these various activities under one direction and control, and my hesitation about acting in the matter has grown only out of a reluctance to take away from the Bureau of Mines a piece of work which thus far it has so effectively performed. The Secretary of War has assured me of his own recognition of the splendid work you have been able to do, and I am taking the liberty of enclosing a letter which I have received from him, in order that you may-see how fully the War Department recognizes the value of the services. I am to-day signing the order directing the transfer. I want, however, to express to you my own-appreciation of the fine and helpful piece of work which you-have-done, and to. say that this sort of team work by the bureaus outside of the direct war-making agency is one of the cheering and gratifying evidences of the way our official forces are inspired by the presence of a great national task. Cordially yours, Dr. Van. H. Manning, WOODROW WILSON. Chief, Bureau of Mines, Department of the Interior. War Department, Washington, June 25, 1918. MY DEAR MR. PRESIDENT: In connection with the proposed transfer of the chemical section at. American University from the Bureau of Mines to the newly constituted and consolidated Gas Service of the War Department, which you are considering, I am specially concerned to have you know how much the War Department appreciates the splendid services which have been rendered to the country and to the Army by the Department of the Interior, and especially by the Bureau of Mines under the direction of Dr. Manning. In the early days of preparation and organization, Dr. Manning's contact with scientific men throughout the country was indispensably valuable. He was able to summon from the universities and the technical laboratories of the country men of the highest quality and to inspire them with enthusiastic zeal in attacking new and difficult problems which had to be solved with the utmost speed. I do not see how the work could have been better done than he did it, and the present suggestion that the section now pass under the direction and control of the War Department grows out of the fact that the whole subject of gas warfare has assumed a fresh pressure and intensity, and the director of it must have the widest control so as to be able to use the resources at his command in the most effective way possible. The proposal does not involve the disruption of the fine group of scientific men Dr. Manning has brought together, but merely their transfer to General Sibert's direction. Respectfully yours, NEWTON D. BAKER.

Jan 9, 1918

[Trans. No.Place Date Vol. Page 1. Wilkes-Barre, Pa.* .... May, '71.. 1 8 2. Bethlehem Pa Aug., '71.. 1 10 3. Troy N. 'l Nov., '71.. 1 13 4. Philadelphia, Pa Feb., '72.. 1 '17 5. New York, N. Y.• ....May, '72 1 20 6. Pittsburgh, Pa Oct., '72.. 1 25 7. Boston, Mass Feb., '73.. 1 28 8. Philadelphia, Pa.' May, '73.. 2 3 9. Easton, Pa Oct., '73.. 2 7 10. New York, N. Y Feb.. '74 2 11 11. St. Louis, Mo' May, '74.. 3 3 12. Hazleton, Pa Oct., '74.. 8 8 13. New Haven, Conn....Feb., '75.. 8 15 14. Dover. N. J.' Mav. '75.. 43] [ ]

Jan 1, 1925

By W. C. Ellis, E. S. Greiner, M. E. Fine

C. H. Samans and W. R. Ham (Chicago, Ill., and Dix-field, Maine, respectively)-—For several years we have been studying transitions of this basic type in metals, alloys, glasses, etc. Usually, however, they are not so clearly marked as those which the authors have found, and hence are much more difficult to determine accurately. Since our studies indicate that most of them occur virtually unchanged (as far as temperature is concerned) regardless of the form in which the element appears, we believe that they are a characteristic of the atom. Specifically, we believe that there is an additional rotational degree of freedom possessed by the nucleus which has not been considered heretofore. This nuclear rotation is made up of several components, each related to the several quantum shells of electrons. In chromium there are four of these shells and hence four separate series of characteristic transition temperatures. The lowest temperature at which any transition occurs, based on the present state of our computations, is 125°K, 4° higher than the authors' value of 121°K. A convergence of this series, we believe, shows up at the higher temperature of 2085 °K, surprisingly close to the transformation temperature of 2103°K recently announced by N. J. Grant of M.I.T. for a body-centered to face-centered transformation in chromium. Likewise, our computations indicate a temperature of 311°K for the second transition temperature, reported by the authors as 310 °K. A convergence of this series, we believe, shows up at a higher temperature as the melting point at 2163°K. Although our work on these series must, in a sense, still be regarded as empirical, since we do not understand fully as yet just what the series mean, it is based on a reasonably firm picture. The individual constants, from which the various series are computed for each element, comes directly from the X-ray K absorption limit. Furthermore, the same basic method has accounted for transformation and melting temperatures in about 50 of the chemical elements, which is all we have tried thus far. In many cases the only known transformation is the melting point, but in others the occurrence of transformations or other transitions, equally as well marked as those of the authors, has been pointed out by others. These observations have assisted us greatly. Consequently we were very pleased to see the authors' excellent work in finding these two transitions in chromium. With these confirming data, our picture of this element is clarified considerably, so we expect that at least some of our work can be published in the near future. R. C. Ruder (E. I. du Pont de Nemours & Cu., Wilmington, Del.)—The authors' interpretation of these transitions in terms of 3d to 4s electronic structure transitions is most interesting. It would be interesting to have additional experimental evidence of such transitions from the temperature dependence of the Hall coefficient in the neighborhood of the property changes discussed in this paper. Simple theory15 suggests the Hall coefficient as a measure of the free electron (or s electron) concentration per unit volume. It has been shown that for paramagnetic'" and ferromagnetic1? metals the simple theory is in fact too simple. However, the existence of a discontinuity in the Hall coefficient would provide information which should aid both in our understanding of these transitions and the significance of the Hall coefficient in these metals. It was rather surprising that no significant paramagnetic effects were observed. In this connection the recent work of McGuire and Kriessman18 is cited. They measured the magnetic susceptibility of chromium from 20" to 1460 °C. They also observed no large change in the susceptibility although there might be a change in slope in the vicinity of the 40 °C transition. The existence of these 3d to 4s electronic transitions has been discussed in connection with the paramagnetic susceptibility behavior of nickel and nickel alloys.'"-" Assuming a correspondence principle between classical and quantum mechanical paramagnetic theory and using classical theory to calculate the effective Bohr magneton number from the Curie constant for substances obeying the Curie-Weiss law," it is found that the effective magneton number is a function of temperature. The process of calculation involves the inverse of the differential of the 1/x4 vs. temperature curve so that good and numerous data are necessary to obtain significant results. The data of Fallot23 show a discontinuous increase of about 12 pct in the effective magneton number between 850" and 900 oC, followed by a continuous increase up to the melting point. The data of Sucksmith and Pearce24 show a possible 8 pct increase. The older data of Terry25 and Weiss and Foex26 show a continuous increase. It is possible that small amounts of impurity atoms change these electronic transitions significantly. Fallot's23 data on a nickel alloy with 4.5 atomic pct Fe indicate that the discontinuity occurs around 1300 °C. Systematic investigation of the transition metals for transitions of this nature should provide information which would be very valuable for our understanding of these metals. The absence of antiferromagnetic structures in chromium has been shown by Shull27 using neutron diffraction techniques. M. E. Fine, E. S. Greiner, and W. C. Ellis (authors' reply)—The remarks by Drs. Samans and Ham are certainly very interesting, in particular those pertaining to the close agreement between the theoretically calculated values for transition temperatures in chromium and the experimental values reported by a number of investigators. This is a remarkable achievement and we shall look forward to a more detailed presentation of the method followed in their calculations. We do not believe that the transition in pure chromium near 40 °C remains temperature invariant with alloying, as was reported by Samans and Ham for a number of the substances that they studied. We have not done any work with alloys but base our belief on the results of earlier studies in which less pure chromium was included and considerably lower transition temperatures were observed. The transition tempera-

Jan 1, 1952

By Keats, J. L.

IN THE literature on the elimination of metalloids in basic open-hearth practice, there are a great many heats recorded in which excellent data on changes in slag and metal composition during refining are given, but in almost all of these heats either temperature data or weights and analysis of charge are unrecorded and observations on the physical charac- teristics of the slag are almost always lacking. With these points in mind, a test heat was made in which as complete as data possible on all the factors that affect the elimination of metalloids were obtained.

Jan 1, 1957

By Arnulf Muan, R. E. Johnson

Equilibrium CO2 /CO ratios of a gas phase coexisting with selected oxide phase assemblages of the system CaO-"Fe0"-SiOz and vnetallic iron have been determined at 1080°C. The data obtained are used to calculate activity-conzposition relations for metasili-cute, orthosilicate, and CaO- "FeO" solid solutions, and to determine a new value for the free energy of formation of C&S&0,. The metasilicate solution is practically ideal, whereas large deviations from ideality exist in the othe,r two solid solutions. BECAUSE of the geochemical and metallurgical importance of the oxides CaO, "FeO", and SiOz, the system CaO-"FeO"-SiO2 has been the subject of several experimental studies during the past 30 years. Following the delineation of phase relations at liquidus temperatures by a group of investigators at the Geophysical Laboratory of the Carnegie Institution of Washington in 1933,1 Chipman and associates in the early forties2,3 determined activities of FeO in liquids of this system. Since that time, many attempts have been made to interpret the data of Chipman et al. in terms of the constitution of the silicate liquids and the interaction parameters among the various constituents of the system (see for instance papers by Richardson4 and by Flood and coworkers5). One of the assumptions made in some of these interpretations4 is that the binary silicate systems CaSiO3-FeSiO3 and CazSi04-Fe2SiO4 mix ideally in the solid state. The objective of the present study is to provide experimental data on activity-com position relations in solid solutions of the system CaO-"FeO"-SiO2. Such data will contribute toward an understanding of the thermodynamics of silicate solid-solution phases in general, and will serve specifically to confirm or refute some of the assumptions made in interpreting liquid slag behavior. PREVIOUS WORK Phase relations in the system CaO-"FeO"-SiO2 in contact with metallic iron were determined by Bowen, Schairer, and Posnjak,1 and additional phase-equilibrium data for this system have been presented by Allen and snow.' A reproduction of the most up-to-date phase diagram for this system is shown in Fig. 1.7'8 Of particular interest in the present investigation are the relations among the various crystalline phases slightly below the lowest solidus temperature in the system, as shown in Fig. 2. The present work will be concerned primarily with some of the composition

Jan 1, 1968

By P. W. Bakarian, John C. McDonald

Three magnesium alloys were processed in various ways to exhibit a wide variation in the ratios of yield strength and tensile strength in the rolling direction compared to the cross-rolling direction. Basal-plane pole figures were prepared from several specimens. A fair correlation was observed between the property ratios and the ratio of percent of poles oriented in the cross-direction quadrants compared to the percent oriented in the rolling-direction quadrants of the pole figures. THE modes by which magnesium crystals deform are such as to lead to marked preferred orientations in all forms of wrought products. The effect of the active modes at room temperature, coupled with these orientations, is often to produce a lower compressive yield stress compared to the tensile yield stress. The phenomenon is due to easy twinning in compression, and has been well-related to the preferred orientations as described by basal-plane pole figures of the hcp magnesium single crystal. The literature contains some information on the variation with test direction of the tensile properties of sheet, but no quantitative relationship to the observed pole figures has been established. These effects have been reviewed in the few com- prehensive treatises in English which have been written on magnesium technology and metallurgy.1°3 Roberts presents several pole figures, but no tensile-property data in the plane of the sheet. Raynor has no pole figures, but quotes Frommer's4 results. The information in Beck's compendium more or less parallels the results of Jones and powell.5 In both a Mg + 1.5 Mn alloy and a Mg + 4.6 A1 alloy, cold rolling was found not to change the general situation of higher properties in the cross-rolling direction,* than in the rolling direction. Thomas'6 X-ray studies of Jones and Powell's specimens did not permit correlation of properties and preferred orientation. Ansel and Betterton7 report tensile and compressive properties on three other alloys as a function of degree of cold rolling, plus a recrystallizing anneal. As rolled, there was a change in anisotropy with degree of reduction, but all alloys were reasonably isotropic in tension when annealed. X-ray diffraction photograms illustrated the kinds of orientations present, but were not correlated with the properties. Bakarian8 has described a method of determining quantitatively a preferred orientation, and illustrated the method by applying it to pure magnesium and two of its alloys. This method was used in the present work as a basis for correlating the strength properties with the texture.

Jan 1, 1965

By E. I. Larsen, E. F. Swazy, F. R. Hensel

Experience has indicated that hard bronzes are not suitable for bearing applications where high bearing loads and speeds are involved. It is the general practice to utilize softer materials for these purposes, such as copper, lead, silver, babbitt, lead-base alloys, and more recently aluminum-base alloys, preferably supported by a steel backing. It was the objective of the present investigation to study a new material produced by powder metallurgical methods susceptible to precipitation-hardening. Test MAteriaIs Preliminary tests were made with compacts containing copper, nickel and silicon in quantities sufficient to form 3 to 5 per cent nickel silicide. It mas found that this type of alloy was susceptible to the formation of a soft surface shell when sintered in tank hydrogen. The depth of the shell depended On the length of sintering time and sintering temperature, and varied in thickness from a few thousandths to as much as One eighth inch. This soft shell resulted from the preferential oxidation of silicon, thereby reducing the efficiency of age-hardening by the nickel silicide compound. The body of the sintered compacts below the soft shell could be precipitation-hardened to a hardness of 70 to 85 Rockwell B, by quenching from goo°C. and age-hardening at 450°C. A series of tests was made with various addition agents, in order to decrease the rate of preferential oxidation, and it was found that phosphorus was most beneficial in this respect. After considerable experimentation, the following nominal com-position was accepted as standard: 2.4 per cent nickel; 0.8 silicon; 0.3 phosphorus; balance copper. The physical propertties and certain bearing properties of this alloy are described in the present paper Preparation of Compacts Several methods of incorporating the hardening ingredient (nickel silicide) were studied. Compacts formed from copper, nickel and silicon powders were found to be inferior to those fabricated from prealloyed nickel silicide master alloys, because of the rapid oxidation of pure silicon during sintering. The use of a prealloyed nickel silicide hardener containing 25 per cent silicon and 75 per cent nickel could be further improved by preparing a master alloy, incorporating nickel, silicon, phosphorus and copper, having the following nominal composition~ 25 per cent nickel; 7 silicon; 3 phosphorus 64 copper. This alloy is brittle in the cast condition and can be readily powdered. Sintering Procedure The blended powders were pressed at '5 to 40 tons per sq' in., the pressure depending on the size and shape of the compacts. Sintering was carried out in hydrogen or cracked ammonia atmospheres at

Jan 1, 1946

By E. I. Larsen, E. F. Swazy, F. R. Hensel

Experience has indicated that hard bronzes are not suitable for bearing applications where high bearing loads and speeds are involved. It is the general practice to utilize softer materials for these purposes, such as copper, lead, silver, babbitt, lead-base alloys, and more recently aluminum-base alloys, preferably supported by a steel backing. It was the objective of the present investigation to study a new material produced by powder metallurgical methods susceptible to precipitation-hardening. Test MAteriaIs Preliminary tests were made with compacts containing copper, nickel and silicon in quantities sufficient to form 3 to 5 per cent nickel silicide. It mas found that this type of alloy was susceptible to the formation of a soft surface shell when sintered in tank hydrogen. The depth of the shell depended On the length of sintering time and sintering temperature, and varied in thickness from a few thousandths to as much as One eighth inch. This soft shell resulted from the preferential oxidation of silicon, thereby reducing the efficiency of age-hardening by the nickel silicide compound. The body of the sintered compacts below the soft shell could be precipitation-hardened to a hardness of 70 to 85 Rockwell B, by quenching from goo°C. and age-hardening at 450°C. A series of tests was made with various addition agents, in order to decrease the rate of preferential oxidation, and it was found that phosphorus was most beneficial in this respect. After considerable experimentation, the following nominal com-position was accepted as standard: 2.4 per cent nickel; 0.8 silicon; 0.3 phosphorus; balance copper. The physical propertties and certain bearing properties of this alloy are described in the present paper Preparation of Compacts Several methods of incorporating the hardening ingredient (nickel silicide) were studied. Compacts formed from copper, nickel and silicon powders were found to be inferior to those fabricated from prealloyed nickel silicide master alloys, because of the rapid oxidation of pure silicon during sintering. The use of a prealloyed nickel silicide hardener containing 25 per cent silicon and 75 per cent nickel could be further improved by preparing a master alloy, incorporating nickel, silicon, phosphorus and copper, having the following nominal composition~ 25 per cent nickel; 7 silicon; 3 phosphorus 64 copper. This alloy is brittle in the cast condition and can be readily powdered. Sintering Procedure The blended powders were pressed at '5 to 40 tons per sq' in., the pressure depending on the size and shape of the compacts. Sintering was carried out in hydrogen or cracked ammonia atmospheres at

Jan 1, 1946

THE committee in charge of arrangements for the meeting of the Institute in September has com-pleted its program. The headquarters of the meeting will be at the Palace Hotel, San Francisco, and the registration committee will be at the hotel all day on Sunday, Sept. 24, and from 8 a.m. until noon on Monday. On Sunday afternoon, automobiles will be available for sightseeing trips around the city. Monday will be devoted to technical sessions. In the morning, there will be sessions on Mining and on Iron and Steel; in the afternoon, sessions on Mining and Milling. At these sessions, in addition to the papers mentioned in the tentative list printed in August, there will be presented three papers on the geology, mining and milling of the Comstock lode; one on the Aztec mine, Baldy, N. M.; one on the Colombian oil fields; and one on charcoal precipitation of cyanide solutions. The luncheon on that day will be Dutch Treat, for men only, at the Engineers Club. On Monday evening, there will be an informal buffet supper at the home of F. W. Bradley. On Tuesday morning, a party of 50 men will leave for Hetch Hetchy. During the four days of the trip, the party will see the Priest tunnel and earth dam under construction by steam-shovel and hydraulic-fill methods, the Big Creek shaft and tunnel, early intake power plant and tunnels and the Hetch Hetchy dam under construction. For those who remain in San Francisco, Tuesday will be "San Francisco Day." There will be motor trips to the Presidio, Cliff House, Golden Gate Park, and other points of interest, and shopping trips to Chinatown. On Wednesday, "University of California Day," the party will be guided through the university by members of the Mining Association, the affiliated stu-dent society, and will see the Greak Theatre and not-able buildings. Thursday will be "Leland Standford, Jr. University Day." Automobiles will leave the Palace Hotel at 10 a.m., and will return from the university at 4.30 p.m. Friday has been reserved for trips to the Selby Smelter, to Mt. Tamalpais, or to other points of interest. Arrangements will be made to visit the mines or gold dredges in California, if members desire to do so, but such trips must of necessity be considered special trips and arrangements will have to be made to suit the convenience of the individual or party. The Golf Committee will make arrangements for those who wish to play golf.

Jan 9, 1922

By Y. C. Liu, R. H. Richman

The effects of gel,manium and tin on the deformation and 9-e-crystallization textures of copper have been explored in detail with in the copper-rich terminal solid solutions. Addition of solute to copper produces a change in deformation texture from the copper type to the 70 :30 brass type. This transition has been measured quantitatively The types mid proportions of recrystal-lization components have been determined as a function of com-position, and correlation of recrystallization components with specific deformation components is discussed. On the basis of information available in the literature, it has been suggested that the effect of solute elements on the recrystallization texture of copper

Jan 1, 1961

There were two official representatives of Foreign Governments as guests at the Chicago Meeting. One was Frederick Goransson, managing director of the Saudvikens Steel Works, who represented the Jernkonteret, the Iron and Steel In-stitute of Sweden, and who came to this country especially for our meeting. The other distinguished guest was Commander Toublet, who repre-sented the French Embassy. Commander Toublet delivered a most polished address at the Banquet, dealing with the felicitous relations existing between this country and France for the last 150 years. Com-mander Toublet was accompanied by Mrs. Toublet, who won the hearts of all the ladies present, whose guest she was.

Jan 11, 1919

The United States has never been a large coal exporting nation, and normally such shipments, aside from those to Canada, have been relatively small. Since the first railroad was built across the Allegheny Mountains, the imports have been quite small also, although fairly large tonnages of Canadian coal have moved into the extreme northeastern and northwestern states at times. In Table 21 are shown all data available about these shipments from 1790 to 1939, inclusive.

Jan 1, 1942

By John J. Cioston

THE steadily rising flood of gold production from all parts of the world has created an avalanche of rumors regarding the stability of the present price of this metal. Markets have been unsettled from Johannesburg to London from New York and Toronto to Melbourne, despite repeated denials from, American and British authorities of any immediate intention to alter the price. Various economists and financial writers have blossomed forth with predictions that the price would be set at the old level of $20.67 per oz.; some have even been so brash as to state That a price of $15 would be necessary to bring production within control. These effusions, based entirely upon monetary theories and with no regard to production costs, serve to confuse rather than clarify the situation.

Jan 1, 1937

By H. O. Hofman

INSTITUTE OF TECHNOLOGY, In deternlining experimentally the fusibility of clays, two kinds of methods may be distinguished—the direct and the indirect. Of the direct methods, that of Seger has found

Jan 1, 1899

By ERNEST A. HERSAY

ACCURATE ore-sizing with screens is drawing attention to certain details that now, more than ever before, require attention. There are many tests that must be preceded by careful sizing. The assayer often could profit by a more careful selection of screens. In milling, more attention is given the slimes produced. Cement-manufacturers are pulverizing and screening finer than they formerly did, and others are reducing materials to fine sizes at high cost, with screens used to govern the fine¬ness of the pulverized product. Fine screens are expensive, easily injured by mis-use, are carried in stock sparingly by most dealers, and are handled often by those who know little about them except their designated number. More attention, on the whole, needs be given the actual size of the mesh-openings, and less emphasis placed upon any custom or conventionality in numbering. An effort to classify wire screens, in this respect, leads at once into computations, where one is confronted with details of sizes and standards, of different wires, different gauges, and different customs. There is always uncertainty about the exact working-size of a screen until one gives the matter special attention, and devotes more time to it than its simplicity seems to demand. To know only the number is not sufficient for all uses. Often, in sets, superfluous sizes are used; and sizes are omitted that are of critical importance. In wire screens, the use of different standard sizes of wire makes important differences in dimensions that must be taken into account. The dealer usually grades screens by the number of openings per linear dimensions, regardless of the size of the openings or of the wire. Certain 100-mesh screens in use are found, by measurement, to he actually coarser than others of 90-mesh, a result which is due, of course, to the use of larger

May 1, 1906

By Coolbaugh, Franklin

CRUSHING of Climax mine-run ore is carried out in two plants: No. 1 plant (flowsheet in Fig. 1) has a capacity of approximately 5000 tons per day. It is used as a stand-by except when maximum production is required. No. 2 plant (Fig. 2) has a top capacity of approximately 17,000 tons per day. The No. 2 crusher is more efficient to operate on reduced tonnages regardless of the wide variation in peak capacities. The system of crushing is similar in both plants: Mine ore, of a size which can be drawn through 48 by 96-in. slusher openings underground, is dumped into the crusher bins from ten-ton mine cars and fed into 48 by 60-in. Buchanan jaw crushers by means of chutes and Ross chain feeders. The jaw crushers are set to discharge at approximately 9-in. size. Jaw crusher discharge is conveyed to 7-ft. Symons standard cone crushers where it is broken to minus-2-in. size,

Jan 1, 1946

By Winston W. Spencer

ALTHOUGH by far the largest A consumer of platinum metals in the world, the United States until recently has been in- significant as a producer. Writing in the "Minerals Yearbook" for 1939, H. W. Davis states that 1938 probably marked the beginning of an- other period of transition in the world production of the platinum metals. In that year, he says, their production in the United States jumped to 49,380 oz., or fourth in the rank of world output. In the ten-year period 1925 to 1934 United States output ,averaged only 8300 oz. Practically all of this sudden in- crease in production is attributable to the introduction of mechanized equipment at the placer deposits in the Goodnews Bay district of Alaska. This district adjoins the Bering Sea and Kuskokwim Bay (accented on the first syllable), and is approximately 120 miles south of the mouth of the Kuskokwim River. The nearest village and post office is Platinum, which lies about eleven miles north- east of the Goodnews Bay Mining Company's camp. A good gravel road connects the mine camp and the village.

Jan 1, 1940

By W. S. CAYPLESS, H. O. Hofman, E. E. HARRINGTON

I. INTRODUCTION. LIME-ROASTING is a term proposed by Ingalls 1 for the operation of forcing air under pressure through a mixture of galena and lime at the kindling-temperature with the object of oxidizing lead and sulphur and of fritting or fusing the charge. If, finely-divided galena were treated in this manner without the addition of lime, the heat set free by the oxidation of part of the lead and the sulphur would be sufficiently great to fuse undecomposed sulphide, and thus stop desulphurization. Besides the chemical action that the addition of lime, limestone or gypsum to the charge may have, the admixture has the physical effect that it keeps the particles of galena separated from one another and accessible to the oxidizing effect of the air. At present, three methods of lime-roasting are carried out on a working-scale, the Huntington-Heberlein, the Carmichael-Bradford and the Savelsberg2 processes. In the last, which interests us here, an 8-ton charge is made up of galena, limestone and perhaps some siliceous or ferruginous flux; the whole is crushed to pass a screen with 3-mm. holes and moistened with 5 per cent of water. It is fed gradually into a bowl-shaped converter, 6.56 ft. in diameter, supported by trunnions attached to a truck. On the .bottom the converter has a grate with blast-inlet beneath. In starting, the truck with the converter

Jan 1, 1907

By M. B. Kasen

eralized strain equation appear quite different they are really identical. This identity can be shown in a simple mathematical rearrangement. Referring to Eq. [I], the substitution of ln(1 +?E) for ? (where ?E is the engineering strain) yields: a =s8- (s8?so)e?1/?c) ln(1 +s8??E) [4] or s =s8?(s8?so)(l +?E)-1 [5] Replacing (1 + cE) with its equivalent, (l/lo): s=s8?(s8?so)l/€c [6] Adding and subtracting the quantity (s8 - so) yields: s=s8?(s8?so)+ (s8-so) l-(^)l/£c [7] = s0+(s8?so)ri-(^0)1/^l [8] Letting n = 1/?c it follows that: This equation will be seen to be identical to the generalized strain expression in Eq. [3], the coefficients a and b being equal to so and (s8?so)/?c or n(s8?so), respectively. Confirmation of the relationship noted above was provided by fitting experimental stress-strain data5 for 304 stainless steel (total strain from 0.072 to 1.15) at room temperature at a true total strain rate of 4 x 10-3 sec-1 to Eqs. [I] and [3]. In this study nonlinear regression analyses were used to evaluate the equation constants. The results of this evaluation are presented in Table I. When these constants are used in Eqs. [I] and [3] the curves obtained are coincident. It will also be noted that the value of n is equal to YE,, the value of a is equal to so, and the value of b is equal to (s8 - so)/Ec. These equalities are illustrated in Table I where the Voce constants in parentheses were calculated from a, b, and n values. Excellent agreement is seen to exist. It is concluded, therefore, that the Voce equation is, indeed, identical to the linear expression involving generalized strain. In applying the generalized strain concept to stress-strain data, it has been noted3 that data within what was termed the transition region (first few points in the plastic flow region) must be excluded from the analysis in order to obtain the linearity in Eq. [3]. A similar exclusion applies in the use of the Voce equation since an expression which would describe the strain-hardening region would usually be found to be not too effective in the elastic-plastic fillet2 which connects the elastic line to the strain-hardening region. These considerations further substantiate that Eqs. [I] and [3] do indeed describe identical behavior. Note added in proof. Since this manuscript was submitted for publication, correspondence with Professor S. R. Davies, University of Edinburgh, (of Ref. 3) indicated that his associates have also confirmed the identity between the Voce equation and the generalized strain concept. It is sometimes desirable to obtain a small grain size in super-purity metals. Unfortunately, the absence of impurities, the low recrystallization temperatures, and the low activation energies for boundary motion result in rapid growth of relatively few grains when conventional recrystallization practices are used. For example, Arajs et al.1 were unable to obtain a mean grain diameter less than about 0.4 mm in iron containing 38 at. ppm of impurity. The <1 at. ppm purity range in many modern superpurity metals results in yet larger limiting grain sizes. It is the purpose of this communication to describe a technique by which mean grain diameters as small as 30 µ have been produced in aluminum having an impurity content < 0.5 at. ppm. The technique should be applicable to superpurity metals other than aluminum and has potential applications to grain refinement of commercial alloys. The necessary and sufficient requirements for production of a small grain size are as follows: a) a large number of potential nucleating sites must be created randomly within the cold worked material, b) sufficient thermal energy must be provided at a rate that will simultaneously activate a large fraction of the potential nuclei, and c) the grain growth must be stopped shortly after grain impingement.&apos; A high density of potential grain nuclei may be cre-

Jan 1, 1970

P. Herasymenko (New York University, New York) —The authors&apos; experiments on equilibria between water vapor and liquid synthetic slags represent a valuable contribution to our knowledge of the nature of liquid slags. They can be regarded as a proof of ionic splitting of water molecules dissolved in slags. The assumption that water dissolved in slag was com- pletely ionized was made in my report on hydrogen equilibria in steelmaking as early as 194010. In that paper, the first systematic data were given on the content of ionized hydrogen in acid and basic open-hearth slags. The paper probably escaped the notice of the authors, although they mention the articles published later by other investigators who reported erratic and

Jan 1, 1958