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By R. W. Diamond

THREE mills are now operated by the Consolidated Mining & Smelting Co. of Canada, Ltd. : (1) The Sullivan Concentrator, Chapman Camp, B. C. (near Kimberley, B. C.), (2) the St. Eugene Concentrator, Moyie, B. C., and (3) the Tadanac (Customs) Concentrator, Trail, B. C. Differential flotation is the only concentration method employed in all three I plants. Tables are used for pilot work only. Values in all ores treated are as minerals of some or all of the metals -lead, zinc, gold or silver. Occasional customs ores contain small amounts of copper. Sulfide iron content of ores treated varies from a [ ] low figure in some ores to 38 per cent. iron in Sullivan ore. Gangue minerals vary considerably. A few customs ores are somewhat oxidized and as a result present difficulties. Flotation equipment and control are similar in the three mills, and the flow sheets at the St. Eugene and Tadanac mills, while much simpler, are modeled after that of the Sullivan Concentrator. In this paper I will not detail treatment nor equipment in any of our plants but will describe special features in, or in connection with, all of them. I will then deal with flotation reagents, describing our use of each of them, particularly where differing from general practice. I will conclude with comments on special subjects related to differential flotation.

Jan 1, 1928

By W. V. Kotlensky, H. E. Martens

In an earlier communication, Ref. 1, the authors presented the tensile properties and the changes in crystal structure and microstructure for pyrolytic graphite tested at 2750°C. It was suggested that changes in the structure may have an effect on the tensile properties of this material. Accordingly, tensile tests were run on a series of specimens, from one block of pyrolytic graphite, some of which were hot-worked by being strained at 2750°C, others of which were tested in the as-deposited condition. According to the manufacturer, General Electric Co., the polycrystalline material was deposited at 2100°C on a substrate of synthetic graphite by decomposition of a dilute natural gas mixture. The as-deposited material had a density of approximately 2.19 g per cc, and as shown in Fig. 1 had a structure of medium size growth cones which were regenera-tively nucleated. All specimens had a gage section 0.75 in. long by 0.06 in. wide by 0.1 in. thick with the thickness direction perpendicular to the basal planes. The testing method and equipment used have been previously described, Ref. 2 and 3. For both the hot-working and the testing the load was applied parallel to the basal planes; a cross-head speed of 1.5 x l04 in, per sec was used. All heating was done in an atmosphere of bottled helium.

Jan 1, 1962

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about-55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 7, 1916

By Stefan Boshkov, Malcolm T. Wane

THE validity and accuracy of velocity measurements underground have been questioned repeatedly by those in mine ventilation work. The general disagreement on the subject is well illustrated in an AIME publication.' Although the presence of errors is readily admitted, their magnitudes are not known and often are described by practical operators merely as "great," "small," or "of no importance." The belief that errors are of academic interest only prevails because of a justifiable claim that actual volumes of air circulated are well in excess of those required by law and safe mining practices. Poor understanding of the source and nature of errors inherent in velocity measurements, coupled with questionable determination of cross-sectional area, result in faulty techniques for the purpose of expediting ventilation surveys and render doubtful the calculated volume. Often consistency of readings is confused with accuracy. A succession of check readings showing a maximum deviation of 5 pct in the measured value of velocity usually signifies nothing more than diligent application of technique in a stable ventilating current. This article discusses the errors involved in air measurements underground. Where instrument errors are presented, the treatment is confined solely to the rotating-vane anemometer, recognized as a most useful ventilation measurement tool because of its simple design and easy operation. In the following pages a positive deviation is defined as one which has to be added to the registered air velocity to obtain the true air velocity.

Jan 1, 1956

By A. J. Brown

THE causes that have formed fissures in the earth's crust, and the agencies that have converted them into metallic beds, are amongst the most important and interesting subjects that can engage the attention of the mining engineer or the scientist. They lie at the very base of the whole system of vein geology, and until something like a correct theory can be arrived at with regard to them, the science as such is necessarily very incomplete. The data for such a theory, owing to a lack of careful and systematic observations in countries pre-eminently metalliferous, like Mexico and the States of Central and South America, are almost entirely wanting. Doubtless there has been abundant speculation on the subject, from the earliest times down to the present, in every country where mining has been one of the leading industries of the inhabitants. Perhaps the theory of Elie de Beaumont more nearly approaches a satisfactory explanation than that of any contemporary authority. The most recent investigations, both in Europe and on this continent, tend to produce the conviction that the phenomena of metallic fissure lodes are in some way connected with, and- dependent upon, plutonic agencies-not, however, as the direct product of volcanic activity, but rather as the result of chemical agencies called into play through its aid. Active volcanoes generally produce only the well-known types of volcanic rocks, though, perhaps, well-marked cases can be shown where these contain ores of copper, etc., evidently derived from the same deepseated source as their hypogene gangue. To prove that there is a connection between metallic lodes and plutonic rocks, it is not necessary that the ores should in all cases occupy fissures within the limits of masses of propylite, rhyolite, or other like rocks, or be

Jan 1, 1874

By H. E. Lee, P. C. Feddersen

Blast-fuRnace operation at the Bunker Hill smelter deviates somewhat from common practice. Under existing conditions it is economical to operate the furnaces at "forced" capacity. The furnace feed consists chiefly of sinter and averages close to 50 per cent lead. Experience in smelting such material favors a low charge column attended by smaller proportions of coke and a low blast pressure. Under such conditions the gain in furnace tonnage greatly overbalances the somewhat higher slag losses and increased percentage of material fumed Furnace Charge The ingredients for the blast-furnace feed are stored in a group of 24 charge bins (3600 cu. ft. capacity). Each bin has two discharge chutes. Beneath each chute is a steel weighing hopper, suspended from a Fairbanks scale. The several hoppers are kept filled with the exact amount of material required to complete a furnace charge. The weighed material is discharged into a standard-gauge, bottom-dump charge car containing two compartments, each of which holds a complete charge (approximately 1½ tons). It is hauled to the blast furnace by a 44011 electric trolley locomotive. The proportionate parts of the various constituents of a representative blast-furnace charge are shown in Table 1. Table 1.—Representative Blast-furnace Charge at Bunker Hill Smelter Material Pounds Sinter.................................................. 2500 Limerock............................................... 0- 50 Coke................................................. 250-300 Scrap iron.............................................. 0-25 Settler skulls.......................................... 75 Undried zinc-plant residue................................ 0-200 Siliceous ore............................................ 25 Baghouse dust.......................................... 0-50 By-product slag......................................... 100 A variable stock tonnage of zinc-plant residue and return by-products results in fluctuations in the percentages of these materials in the blastfurnace feed. Accompanying such variations are corresponding increases or decreases in the amounts of coke, limerock and scrap iron necessary to obtain good furnace operation and adequate reduction.

Jan 1, 1937

By Charles H. Behre

This paper discusses education and training for economic geologists other than petroleum geologists. Candidates enter economic geology through liberal arts colleges, engineering schools and university graduate study. Whatever their backgrounds, rigorous courses are desirable-now conceded in theory, but not adequately recognized in practice. Besides basic sciences (each studied long enough to give a fair comprehension of its basic tenets), a functional command of English and two modern foreign languages is needed, as well as a broad understanding of mining, milling and metallurgy. A year of economics and finance is recommended. Surveying and drafting are essential skills. Yet geology should be represented in each term; otherwise the initial enthusiasm for the science, once contact is broken, may never be regained. A five-year curriculum is thus designed to take care of all major requirements and culminate in the M. S. degree. This curriculum reduces "cultural" courses below the average liberal arts requirements, but this is regarded as necessary. The pursuit of "culture" is assigned, as in most engineering and medical curricula, to extra college years or extracurricular time. To avoid the danger of over-crowding the schooling, the Doctorate in geology is preferred wherever possible. Its two added years should permit wider professional education; more browsing in "cultural" pastures; due attention to broader social implications; and some training in the research now increasingly required of the mineral industry. "In-course" training through cooperation between school and industry is especially advocated. The Institute should take the initiative in stimulating this practice.

Jan 1, 1947

By E. H. Barton

The necessity, on the Pacific Coast and throughout the semiarid regions in particular, of the conservation of waters for agricultural, industrial and mining purposes has forced itself upon the minds of those directly or indirectly interested in these industries. To meet the requirements of the case, storage must be provided for the flood-waters so abundant during the rainy season in order to insure a constant and unfailing supply during the summer months. Such storage can only be obtained, in the greater number of instances, by the erection of reservoir-walls of great height. The feasibility of employing earth or timber in the construction of such high dams is questionable, especially when (as is often the case) they must be placed in torrential streams. The experience of recent years with masonry dams, throughout this and foreign countries, has demonstrated that such dams, when intelligently and correctly designed and properly constructed, will meet the requirements of larger storage by means of increased height. The failures of masonry dams have been few; only two of any consequence being on record, namely, that of the Puentes dam, in Spain, in 1802, and that of the Habra dam, in Algiers, in 1810.* On the other hand, the failures of wooden and earthern dams are innumerable. The following are some of the most important structures constructed in recent years. The list is taken from Mr. Wegmann's book, just cited: The Furens, Zola, Ternay, Ban and Verdon dams, in France; the Nizar, Lozoya, Villar and the two Hizar dams,

Jan 1, 1900

By Leon Dominian

The lack of Aryan roots for the names of metals commonly known among the Aryan settlers of Asia Minor, as well as the later colonizers of Europe, indicates that these races were generally ignorant of the use of metals until they came into contact with Semitic peoples. Practically all mining-terms in current use among the earliest Greeks resemble very strongly their distinctly Semitic equivalents, which can be traced all the way in a broad belt beginning in Lower Mesopotamia, and extending westwardly to the Syrian shores of the Mediterranean. The Greek word 'metallon," for instance, used indiscriminately to designate mine or ore, probably came from the earlier Semitic equivalent, " matal." Again, the Greek words " chry-sos " (gold) and " chalkos " (copper) seem to be descended from the Semitic forms " chrouts " and " chalak." It is a natural inference that primitive mining-methods were evolved by the dwellers in the mineralized areas of Asia Minor, from whom later Greek, Roman, and even North European miners obtained their first not.ions of the reduction of metallic ores, by

Jan 1, 1912

By Fritz Wald, Richard W. Stormont

lHE general constitution of a number of metal-lead telluride and metal-tin telluride systems has recently been studied in an effort designed to furnish background information for the study of degradation mechanisms on junctions between thermoelectric power generation materials and metals.1"4 This paper reports further results of that effort. It was found that cobalt-lead telluride constitutes a stable pseudobinary section through the ternary Co-Pb-Te system. Materials used in the study were lead and tellurium of semiconductor-grade purity (American Smelting and Refining Corp., 99.999+ pet). Cobalt (Johnson Matthey & Co., 99.999 pet purity) was used in the form of slices cut from rods of 5 mm diam. Twenty- gram charges of the alloys were melted in evacuated quartz ampoules. Thermal analysis, as described previously,2'3 and metallographic and X-ray diffraction methods (Debye-Scherrer photographs) were used as investigative tools. Substantial difficulties were encountered in polishing, as reported previously for the lead telluride-iron system.3 A number of different etches were used, including dilute aqua regia, Murakami solution, an etch containing copper nitrate,3 and HC1-HNO3-acetic acid-water mixtures. None of these etches gave consistent results over the complete range of cobalt concentrations. On the alloys containing bulk cobalt in the form of primary

Jan 1, 1969

By O. U. Bradley

THE methods of handling the oil output of the mid-continent fields are not unlike those practised in other oil fields of the United States, and it is not expected that this paper will present any entirely novel ideas. Some features of the practice of handling this oil may be of interest, however. WOODEN CAGING TANKS Practically all of the oil sold to pipe lines and other purchasing agencies throughout the Mid-continent field is gaged from wooden tanks. Steel gaging tanks are slowly coming into use, and are preferable in many ways-leakage and evaporation are reduced, and the strapping and recalculation of capacities are unnecessary. The wooden tanks are slightly coned to facilitate tightening the hoops. The-sizes in, common use are 250, 500, 800 and 1600 bbl. The number and the capacity of the gaging tanks upon any producing oil property depend upon its production, and the facilities for disposing of the output. The 1600-bbl. size was the most common in the Cushing field, particularly during the period of flush production. The tanks are distributed over the leased premises in groups of two, three, and four tanks each, and these are filled from flow tanks, or through direct pipe connections with the heads of the wells. Flow tanks are merely temporary reservoirs to facilitate the transfer of oil from the wells to the gaging tanks. They diminish fire risk,, and are considered indispensable on small producing properties where .water is pumped with the oil, as they permit the refuse and water to settle out before the production is run to the gaging tanks.

Jan 3, 1918

By H. R. Tunnell

EVERY ONE connected with a mine knows that it is hard to keep down the costs of moving ore from the place where it is broken to the shaft or portal. Considered broadly, the subject of handling would cover all work done in a mine, but here it has been limited to handling ore in stopes and drifts, through chutes, and on levels. Good Ventilation and a strict enforcement of rules for the prevention of dust safeguard the health of the men and lower transportation costs. HANDLING ORE IN STOPES AND DRIFTS The object of all stoping is to mine ore of good grade at low cost. In Butte, the major part of the ore is mined, from Veins dipping from 60° to the horizontal to those which are vertical, by means of, square-set, rill, -timbered-rill, and back-filling stopes. When blasted, a part of the rock is carried by gravity to the grizzlies over the chutes, the rest is shoveled. Rock, when broken in a stope, may be deflected by inclined floors or slides toward the top of a chute leading to the level below. Ore broken clean enough to ship should be carried, by the force of its fall, into a chute or as nearly into that chute as the safety of the stope and the men permits. Ore that requires sorting, about 80 per cent. of all ore mined, is caught on a grizzly and the waste picked out. Waste rock broken in a stope is used to fill that stope and should be blasted into the gob with as little handling as possible.

Jan 2, 1922

By F. T. Lee

Directional dependence of strength and deformation properties of the Mount Waldo granite pluton in southeastern Maine is controlled by joints and microfractures whose orientations are linked to flow- induced alignment of microcline crystals. Longitudinal and cross joints which formed during cooling of the mass, as well as much younger sheeting fractures, are commonly associated with subparallel, discontinuous microfractures. The orthogonality of microfractures (open, closed; filled, unfilled; bubble planes) establishes the ease of splitting of the granite. The easiest splitting direction (rift) is subhorizontal, the second easiest direction (grain) is parallel to the cross joints, while the direction of least easy splitting (hardway) is parallel to the longitudinal joints. Static and dynamic measurements made in the field and laboratory established that structural features are responsible for the marked stiffness anisotropy of the granite. In the central part of the pluton the static Young's modulus in the north-south direction averages 31.1 GPa, and 20.9 GPa in the east-west direction; the stiffer direction being parallel to the long C-axes of microcline phenocrysts and microfractures as identified in outcrop, core samples, and thin sections. Vertical downhole sonic measurements of dynamic moduli ranging from 2.5 to 16.2 GPa appeared to be anomalously low when compared to the static horizontal values. However, the field sonic values were confirmed by laboratory sonic pulse testing of oriented cores. The field results reflected closely spaced layers of open horizontal microfractures. Those deformation and strength properties that are closely tied to bubble planes, filled microfractures, and microcline orientation could be extrapolated to greater depths with good hope of success.

Jan 1, 1984

By S. F. Shaw

THE principles involved in lifting oil in wells flowing naturally are identical with those underlying the flowing of wells by means of the air-gas lift, and information of a dependable nature obtained in the study of the air-lift can be applied to wells with natural flow. A well flowing naturally is one in which the lifting is done by means of the gas-lift, for which the gas is supplied entirely by the formation from which the oil is derived. In air-gas lift operations, there is insufficient gas supplied by the formation to lift the oil to the surface in an efficient manner, therefore additional gas for this purpose must be furnished from an outside source. There may, at times, be conditions obtaining in natural flowing wells different from those in wells flowed by gas-lift, but these differences do not at all conflict with the main principles of gas-lift work. One such condition is met with in wells in which the gas supplied by the formation is in considerable excess of that required to lift the oil to surface; this excess may be so great as to reduce the quantity of oil that can be lifted through the particular diameter of casing or tubing that has been lowered into the well. This same condition can be brought about, however, by supplying a large excess of gas from an outside source to an artificial gas-lift well, and a study of the effects obtained from injecting a large excess into the well can be applied directly to handling wells flowing naturally which have a large excess of gas supplied by the underground reservoir.

Jan 1, 1929

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received. may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 3, 1915

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The, time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued,-,and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 5, 1914

By Oliver C. Ralston, Foster Fraas

Electrostatic methods of separation are used only when some peculiar advantage is gained. Such cases are minerals that are not separable by differences in specific gravity or magnetic response and that are desired in particles as large as 10-mesh, a size on which flotation separation is inefficient. This paper covers several separations of this type and others. It includes studies in the electrostatic behavior of kyanite, sillimanite, and zircon, simple silicates that cannot be called either acid or basic but are more nearly neutral. Kyanite and sillimanite are both desired in 10-mesh size and are difficult to bene-ficiate from low-grade ores to give that type of concentrate. A separation of garnet from diopside was studied because this mixture had been removed from a wollas-tonite product by drying and magnetic separation, and no special or extra-preparation for electrostatic separation was necessary. The Separator The separator used in these tests is of the nonhomogeneous field type shown in Fig Ia. It consists of a 11.4-cm-diam rotating metal roll 2 at ground potential over which the dry mixture of minerals is fed. The roll serves as one electrode of the separating field, and the other electrode is that of 3, a smaller 5-cm-diam rotating metal cylinder which is held at a high direct-current potential. In this paper the term "electrode" will be confined to the electrode at 3, roll 2 being designated only as "roll."

Jan 1, 1949

By Cornelius Kelley

VOLUMES have been written about the organizing genius of American industrialists. American methods of production are being studied by the manufacturers of other nations to ascertain the prac-ticability to foreign adaptation. Mass production and the mechanization of industry have become terms of popular understanding and significance. Our people think, act and talk in terms of economic nomenclature. Under these circumstances is it not a matter of supreme importance that Americans themselves should make an analysis of their own situation? National supremacy has been but a transitory event. Wealth has had no fixed abode, and commerce has followed no permanently established route. One hundred and fifty years, viewed from the abstract idea of time, is but a moment in the fact of continuous or successive existence, yet it measures. the cycle that has witnessed the growth of America from a struggling embryonic union of thirteen colonies estab-lished along the Atlantic seaboard to the nation of un-rivalled proportions, vast wealth, huge enterprises and productive energy that now exists beneath the protec-tion of and renders allegiance to the flag that but then had been created. To appreciate fully the significance of what has occurred, it is necessary that there should bee an understanding of the basic factors that have con-tributed so largely to the realization of our present situation. Among the most important were: First, the establishment of a government that was founded upon the principle of affording the widest pos-sible opportunity for individual effort and accom-plishment. Second, there existed a virgin territory of vast extent, endowed by nature with elements of potential wealth far exceeding that possessed by any other like area upon the globe.

Jan 8, 1928

The following is an incomplete list of members and guests who called at Institute headquarters during the period Sept. 10, 19188 to Oct. 10, 1918. Thomas J. Adams, Rahway, N. J. A. N. Mackay, London, England. Henry M. Ami, Washington, D. C. A. W. MacNichol, San Francisco, Cal. Chester Atkinson, Peru, South America. Ernest Marquardt, Casper, Wyo. Bennett R. Bates, Berkeley, Cal. Lieut. S. A. Mewhirter, Denver, Colo. Robert S. Botsford, Petrograd, Russia. William A. Nelson, Nashville, Tenn. Juan Felix Brandes, Santa Barbara, Cal. Robert W. Olinger, Bahia, Brazil, So. G. A. Collins, Seattle, Wash. Amer. C. V. Corless, Coniston, Ont., Canada. G. Preumont, La Paz, Bolivia, So. Amer. F. T. Eddingfield, Washington, D. C. William H. Rettie, Yonkers, N. Y. C. Mason Farnham, Barre Plains, Mass. . Julius Segall, Minneapolis, Minn. F. N. Flynn, Trail, B. C., Canada. Robert Y. Seip, Franklin, N. J. Duncan D. Forbes, Humboldt, Ariz. H. M. Schleicher, Boston, Mass. Alexandre Gouvy, Paris, France. Chester Steinem, Ft. Monroe, Va. Henry G. Granger, Cartagena, Colombia, A. L. Sweetser, Pittsburgh, Pa. So. Amer. . H: E. Treichler, Creighton Mine, Ont., E. Harms, El Paso, Tex. Canada. Alfred G. Heggem, Tulsa, Okla. Frank A. W. Tullock, Yumbo, Colombia, H. B. Henegar, Mascot Tenn. So. Amer. A. M. Kivari, Denver, Edward I. Williams, Ft. Monroe, Va. T. M. Kniffin, Brookline, Mass. Alfred W. G. Wilson, Ottawa, Canada. Charles Lehman, London, England. Donald H. McLaughlin, Camp Meade,Md. C. E. Addams, who recently resigned as general manager for the Arizona Hercules Copper Co., has leased the Ray silver-lead property three miles from Ray, Ariz. Bennett R. Bates has resigned his position as general superintendent of the Cubo Mining & Milling Co., in order that he may take the examination for an officer of engineers.

Jan 11, 1918

By Minoru Sasabe, Mayurni Sorneno, Kazuhiro Goto

I) The Object of the Present Experiment. When the oxygen chemical potential in the gas phase is changed, the oxygen chemical potential in the liquid metal or in the liquid oxide phase will be subsequently changed. The object of the present experiment is to develop a method of measuring the change in the chemical potential of oxygen in liquid metals and in liquid oxides with respect to time, when the oxygen potential in the gas phase changes. II) The Experimental Method. The following types of the oxygen concentration cells with the solid electrolyte of Zr0z-CaO are used: KAZUHIRO GOTO, MemberAIME.MINORU SASABE,and MAYUMl SOMENO are Associate Professor, Research Associate, and Professor, respectively, Department of Metallurgical Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan. Manuscript submitted March 12, 1968, EMD. Igas phase liquid Ag or Pb ZrO2-CaO electrolyte!, The measured reversible electromotive force can be expressed by the next equation, provided that the transference number of the oxygen anion in the electrolyte is unity: E = RT/nF log (at electrode I)/P~ (at electrode 11) where is the electromotive force, R is the gas constant, T is absolute temperature, n is valence of oxygen anion, and Pq is the oxygen pressure at the electrodes. As shown in the previous work1 of the authors, the electromotive force is determined by the difference in the chemical potential of oxygen at the vicinity of the interfaces between the solid electrolyte and the electronic conductors used for the two electrodes. Fig. 1 shows the two kinds of the cell assembly used to measure the change of the chemical potential of oxygen in liquid metals and liquid oxides with respect to time. In both cases, the change of the oxygen pressure in the gas phase is measured by the independent oxygen concentration cell located above the

Jan 1, 1969