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By Ernest F. Burchard

A Reconnaissance of the manganese- and chrome-ore deposits of Cuba was made by the writer, as a representative of the U. S. Geological Survey, in company with Mr. Albert Burch of the Bureau of Mines, under instructions of the Secretary of the Interior, in the spring of 1918. The Cuban Government courteously detailed Sr. E. I. Montoulieu, a mining engineer connected with the Treasury Department, to act as escort and associate throughout the work on the island. The object of the study was to obtain authentic information for use of the United States Government as to the location, character, quantity, and availability of the manganese- and chrome-ore deposits in Cuba. Accordingly, the work comprised examination of such deposits as seemed to be of promise, without regard to stage of development, with a view to a determination of the quantity and quality of ore likely to become available for shipment during 1918 and 1919, and of the tonnage of ore in reserve. Wile it was possible to visit most of the deposits that seemed to be of promise, there was not sufficient time to visit all that were brought to our attention, some of which may have merit. Moreover, the necessity for paying particular attention to the ore deposits and the mines precluded the possibility of making more general studies of the geology of the region, and of making satisfactory collections of country rock and of fossils, and so for other details as to the geography and geology of Cuba the reader is referred to the report by Hayes, Vaughan, and Spencer.l Mr. Burch returned to the United States about 10 days in advance of the writer, who continued, in company with Sr. Montoulieu, investigations of reported deposits in Pinar del Rio, Matanzas, and Santa Clara Provinces. On his arrival in Washington, Mr. Burch submitted to the Director of the Bureau of Mines a summary of the results of the work to date. Later the writer published, as Press Bulietin 190. 380 of the U. S. Geological Survey, a statement concerning the chrome and man-

Jan 1, 1920

By L. C. Graton

The federal taxes on incomes and excess profits are of course heavy. In 1917, the value of the mineral production of the United States was a little in excess of $5,000,000,000. The total of federal taxes for that year, for the mineral producing companies, as computed by themselves, amounts, according to tentative compilations, to about $207,000,000, and the total for the comprehensive group of mineral and metal industries to about $766,000,000, which figures represent respectively 9.5 per cent. and 35.1 per cent. of the total tax paid by all corporations. Because of greater complexities in applying the revenue laws to mineral properties than to most other industries, opportunity is afforded for wide differences of view. The taxes indicated above, therefore, are not final and may conceivably be very materially increased. For 1918, the taxes are expected to be still greater, but no compilations are yet available. Taxes at a high rate are to continue indefinitely. The subject is clearly of gravest import to the mining industry in particular. The Commissioner of Internal Revenue, who is charged by law with the administration and collection of the taxes, is determined that these functions shall be performed in a just and businesslike way. Fairness and finality are to be the chief objectives. In view of the peculiar conditions that attach to the tax program as applied to mines and other wasting industries, like oil, gas, and timber, the Commissioner has resorted to professional advice and assistance by manning a Sub-division of Natural Resources with competent engineers, brought in from the several industries, into whose hands he has placed for solution the technical questions involved. These engineers have a two-fold duty: (1) to devote to the solution of these problems their own knowledge and experience; (2) through their acquaintance with their respective industries, and with the men engaged in those industries, to focus upon these problems, by conferences and otherwise, the best opinion of the country. The principal object of this paper is to acquaint the mining profession with the attitude of the

Jan 1, 1923

By L. C. Graton

The federal taxes on incomes and excess profits are of course heavy. In 1917, the value of the mineral production of the United States was a little in excess of $5,000,000,000. The total of federal taxes for that year, for the mineral producing companies, as computed by themselves, amounts, according to tentative compilations, to about $207,000,000, and the total for the comprehensive group of mineral and metal industries to about $766,000,000, which figures represent respectively 9.5 per cent. and 35.1 per cent. of the total tax paid by all corporations. Because of greater complexities in applying the revenue laws to mineral properties than to most other industries, opportunity is afforded for wide differences of view. The taxes indicated above, therefore, are not final and may conceivably be very materially increased. For 1918, the taxes are expected to be still greater, but no compilations are yet available. Taxes at a high rate are to continue indefinitely. The subject is clearly of gravest import to the mining industry in particular. The Commissioner of Internal Revenue, who is charged by law with the administration and collection of the taxes, is determined that these functions shall be performed in a just and businesslike way. Fairness and finality are to be the chief objectives. In view of the peculiar conditions that attach to the tax program as applied to mines and other wasting industries, like oil, gas, and timber, the Commissioner has resorted to professional advice and assistance by manning a Sub-division of Natural Resources with competent engineers, brought in from the several industries, into whose hands he has placed for solution the technical questions involved. These engineers have a two-fold duty: (1) to devote to the solution of these problems their own knowledge and experience; (2) through their acquaintance with their respective industries, and with the men engaged in those industries, to focus upon these problems, by conferences and otherwise, the best opinion of the country. The principal object of this paper is to acquaint the mining profession with the attitude of the

Jan 1, 1923

By Arthur Forsyth

A SEARCH through the available literature shows that the cobalt-nickel-silicon system has not been systematically studied. This seems rather odd because all three elements are fairly abundant and have better than average corrosion resistance; however, they have high melting points, which makes experimental work difficult. Cobalt and nickel form a continuous series of solid solutions and each metal dissolves about 7.5 per cent silicon. Many ternary alloys have been studied and the results have been published in a great many different ways, but to present such data in a short but clear and understandable manner is still a problem. The following pages describe the results of the study of 76 alloys from which the partial ternary diagram (Fig. 1) of the cobalt-nickel-silicon system has been drawn. The alloys were chosen according to the plan in Fig. la by taking definite ratios of cobalt and nickel, such as 70 Ni, 30 Co or 40 Ni, 60 Co, and adding silicon in various percentages. Each section was studied in detail by means of thermal analysis and microscopic examination, but only two of these detailed sections were thought necessary in the point perspective drawing to give a comprehensive picture of the liquidus, solidus and solid transformations that take place over the temperature ranges studied. Complete thermal analyses and microscopic data are given in Table 1.

Jan 1, 1940

By A. H. Bell

Continued low prices and restricted markets for crude oil discouraged drilling activity in Illinois oil fields during 1933. Only 36 wells were completed in the state, the smallest number since 1904, and of these the majority were scattered wildcat wells, only 10 having been drilled in producing fields (Table 2). Production was curtailed approximately 40 per cent for the first half of the year. During July, August, and the early part of September there was no restriction on production. On Sept. 8, under the "code of fair competition for the petroleum industry," the quota of allowable production for Illinois was fixed at 12,000 bbl. per day. The state's production in 1933 was 9 per cent less than in 1932. What it would have been had there been no curtailment of production and if economic conditions had permitted a normal amount of cleaning out and repairs to wells, it is not possible to estimate, but it would no doubt have been considerably more than the actual figure. No new pools or new producing horizons were discovered in 1933, but the deepening of a Robinson sand well in Crawford County to the McClosky "sand" horizon (St. Genevieve limestone of the Lower Mississippian) resulted in a production of 3 bbl. per day (Fred Patchel, Savilla Shipman No. 5, NE. 1/4, SW. 1/4, sec. 26, T.6N., R.l3W., deepened from 1122 to 1388 ft., to be tested to the McClosky horizon, and, owing to the rapid variations in porosity within short distances, as shown in the Lawrence County field to the south, one test may not be considered as proving or condemning any large area. The average price of Illinois crude oil in 1933, calculated from the posted prices as published in the Oil and Gas Journal and Oil Weekly, was $0.862 per barrel. This compares with a calculated average price of $1.032 in 1932 and 0.852 in 1931. The total value of Illinois crude oil produced in 1933 obtained by multiplying the average price (0.862) by the total production (4,227,000 bbl.) was $3,643,674. Of the 26 wildcat wells drilled in 1933, only one was drilled on known favorable structure. This was the Walmar Oil Company's William Pepple well No. 1, sec. 12, T.4N., R.12W., Hancock County, which tested

Jan 1, 1934

By E. N. Harshman

Uranium mining and milling are rather new industries in Wyoming and South Dakota, but, in the past 15 years, ore valued at more than $400,000,000 has been mined and milled in the region. The major uranium deposits are in structural and/ or erosional basins or on the flanks of uplifts. The principal host rocks are medium- to coarse-grained sandstones that were deposited in continental or brackish-water environments and were derived in large part from the granitic cores of the uplifts and the sedimentary rocks that flank the cores. The ages of the host rocks range from Cretaceous to Miocene, but more than 95 per cent of the known reserves in the region are in rocks of early Eocene age. The bulk of the ore in the region is unoxidized and lies below the water table; some oxidized ore has been mined in the Powder River Basin and Black Hills districts. The unoxidized ore comprises pyrite, uraninite and/ or coffinite, marcasite, hematite, jordisite(?), and selenium. Minerals in the oxidized ore include hydrous uranium carbonates, phosphates, and sulfates and hydrous uranium and/ or vanadium silicates. The deposits are in the form of ore rolls that contain from a few hundred to a few hundred thousand tons of ore, ranging in grade from 0.1 per cent to 1.0 per cent U3O8. The rolls are at the margins of large tabular bodies of sandstone that has been altered by the orebearing solutions. The deposits are believed to have resulted from the interaction of an alkaline; oxidizing, ore-bearing ground water and a reducing environment. Exploration guides include the spatial relations of ore to altered sandstone, favorable lithology in the host rock, the content of certain elements and/ or compounds in ground water, and the relation of deposits to major paleodrainages.

Jan 1, 1968

Edward Keller, Baltimore, Md. (communicatioin to the Secretary*):—It is pleasing to note the increasing amount of work on metallurgical problems that is being carried on by exact scientific methods, and the results of such labor issued by the laboratories of our universities. Without doubt, Mr. Bolles's paper will be welcomed by all progressive practitioners. Many of the results which Mr. Bolles presents to as are new; and I take exceptioil to a few minor points only. The first of his concluding remarks is as follows: "Mattes are not homogeneous, but are composed of distinct mineral entitier, and may be likened to igneous rocks, in which the mineral constituents fall out upon the lowering of the temperature and ensuing solidification." He quotes an introductory remark to a paper1 of mine, as follows: "The true chemical character of copper-mattes does not yet seem to have been definitely determined, i.e, it is still more or less of an open question whether they are true chemical compounds, or mixtures, such as igneous rocks." This quotation, taken alone, would convey the impression that Mr. Bolles's conclusion is entirely new. Had he quoted also another paragraph from my paper in question, it would be clear that he was, to a certain extent at least, anticipated. I take the liberty, therefore, to state the substance of my own work. In the paper referred to, I showed the existence of the phenomenon of liquation in mattes, and, continuing, said: " A more direct method to test whether a matte is a compound sulphide or a mixture of individual sulphides was attempted by applying hydraulic separation. A clean piece of matte was selected containing practically no magnetic oxide and of the following composition: Cu, 37.96; S, 24.45; Fe, 33.63; Zn, 1.25; Pb, 1.02 ; Sb, 0.26 ; As, 0.065 ; insoluble, 1.15 per cent. ; Ag, 26.7 ; Au, 0.04 oz. per ton. For such a test it is essential to select a chemically uniform piece, other-

Jan 1, 1905

By H. William Ahrenholz

The coal industry had another prosperous year in 1966. Since the turn of the decade, production has been climbing at an average rate of 6% per annum. Although the fast pace slackened somewhat, 1966 production showed a gain of almost 3 % over that of 1965. An impressive record can be drawn from the fact that output per man-day in 1966 was more than twice that of the early 1950's, and more than three times that of the early 1940's. And even though man-power requirements lessened, those men retained by the industry worked longer hours and benefited through higher hourly pay rates. However, cost to the customer increased a little. Such statements can only be made for a healthy industry -one that is constantly improving its efficiency. Coal currently provides more than 25% of the total U.S. energy output. About 50% of all U.S.- mined bituminous coal goes directly to the electric utility market. It should be noted that, now, well over one trillion kwh of electricity is generated annually. Dependence of the giant electric utility industry on coal is based on economy and an abundant, dependable supply of this fuel.

Jan 2, 1967

By H. De Cizancourt

The Pechelbronn (Alsace) field is the only important French producing field. During 1934, development was carried on as in previous years. The total output of this field reached 553,575 bbl. in 1934, showing a slight decrease from the 1933 figures. Of the total, 315,000 bbl. (56 per cent) was extracted by drilling, while 238,875 bbl. (46 per cent) was obtained by means of shafts and galleries. Exploration of deep Jurassic and Triassic horizons was still in progress at the end of 1934. A deep well reached the Upper Triassic at a depth of 34 m. (2736 ft.). (Information kindly supplied by M. S. Mena, Directeur Technique.) As mentioned before, the small Gabian field (Herault) is gradually being exhausted. No drilling operations were undertaken in 1934, the small production being restricted to the pumping of old wells. Two exploration wells, noted as "drilling" at the end of 1933, were completed in 1934; viz., Lavelanet (Ariége) at 3785 ft. and Santenay (Niévre) at 2578 feet. French Possessions Algeria.—No drilling at Tliouanet. Out of a total of 100 wells drilled in the area, only 8 are still producing. No exploration work is reported during 1934 in Algeria. Tunisia.—Two wells completed; one well drilling at the end of 1934. A total of 11 wells is reported to have been drilled before the beginning of 1935; out of these, 8 were completed before the present program was begun. Morocco.—Exploration work progressed actively last year. The outstanding event was the coming in of Ts. 26 well at 1243 ft. This well took fire, therefore great difficulties were encountered in the accurate measurement of initial production; the figure of 1500 bbl. of oil given here is a near estimate. Oil flowed accompanied by a great amount of water. The apparent decrease of drilling operations in 1934 is explained by the increase in field activities after the results of Ts. 26 were known;

Jan 1, 1935

SME Membership Directory Listings of record March 31, 1072 SOCIETY OF MINING ENGINEERS OF AIME

Jan 7, 1972

Jan 1, 1947

Jan 1, 1947

By William H. Bassett, C. J. Snyder

Cable sheaths made from common lead have been used to protect underground cables since the beginning of the power-cable industry. Only within the last few years, however, has a systematic study of the production methods and of the causes of failures in cable sheathing been undertaken. Recent increases in the use and demands for service made upon power cables have emphasized the importance of high-quality cable sheaths. It was customary for the users to attribute the cause for their sheath failures to the lack of purity of the lead, but this contention has not been borne out by field and laboratory inspection of the sheaths. During the past two years the writers have had an opportunity to examine various types of sheaths that were removed from power cables after failure. These samples were obtained from various parts of the country and represent, it is supposed, the production of the principal cable manufacturers. Aside from corrosion, the common field difficulties can be classified either as mechanical or structural, as outlined below, and when structural irregularities are found they can all be attributed to manufacturing causes and in no way reflect the purity of the lead. Clasxification of Cable Sheath Failures Other Than Corrosive Mechanical Irregularities A. Splits caused by excessive internal pressure B. Injuries such as nail holes, cuts, tsars, etc. C. Intercrystalline cracks caused by vibration Structural Irregularities A. Splits C. Voids in wall of sheath a. Caused by imperfect welds a. Blisters 13. Holes through sheath b. Laminations a. Caused by yellow oxide inclu- D. Questionable structures sions in sheath wall a. Prominent flow lines b. Blowouts by entrapped gases b. Large areas filled with suboxide during manufacture c. Scattered yellow oxide or dirt C. Caused by inclusions of dirt and

Jan 1, 1933

By BARONJUPTNER VON JONSTORFF, Andrew A. Blair, GUNNAR DILLNER

IT is a well-known fact that the results of different analysts, when operating on the same identical sample of steel or iron, are far from concordant, and it not infrequently happens that great annoyance and trouble in the commercial community are occasioned by these discrepancies. Attempts have been made at various times to investigate the causes of such differences and to obtain more reliable methods of analysis. The most important of these was made by the British Association in 1889: The following gentlemen, with Sir W. Roberts-Austen as Chairman, and Professor T. Turner as Secretary, were constituted as a committee to investigate the question, viz.: Sir F. A. Abel, Mr. Edward Riley, Mr. G. J. Snelus, Mr. John Spiller, Professor J. W. Langley, and Professor Tilden. Average .samples of steel were prepared in America under the superintendence of Professor J. W. Langley. The steels, in the form of turnings, were divided and distributed to sub-committees in Great Britain, America, France, Germany, and Sweden. In Sweden Professor Åkerman acted as Secretary to the Swedish committee. The Government Department of Tests was appointed in Germany; Mr. Ferd. Gautier in France; the British Association Committee in England; Messrs. William

Mar 1, 1905

By James R. Holden, Frederick E. Wang

Through both single-crystal and powder X-ray diffraction methods, ten A6B23-type compounds have been confirmed to exist between lanthanides (A) (plus scandium and yttrium) and manganese (B); A = Y, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu. The formation of a compound of this type is shown to he extremely atomic size-sensitive; hence it can be classified as a "size-factorH compound. The "enveloping effect", a geometrical consideration observed in its crystal structure, is proposed as the reason for the A6B23-type compound being size-sensitive. The approximate ideal geometrical ratio of the radii R/r is 1.31 while experimentally A6B23-type compounds have a radius ratio lying within the range 1.2 to 1.4. FLORIO t al.' characterized the structure of Th6MnZ3 as fcc, space group Fm3m, with 116 atoms in the unit cell. Since then, a number of isotypic binary compounds, and recently Gd n,,' have been confirmed to exist. The fact that strontium and barium form A6Bz3-type compounds with magnesium strongly suggested the possible existence of Ba6Liz3. However, investigation3 showed the compound Ba6LiZ3 to be absent. Since both strontium and barium are group 11-a elements and are therefore "open metals",6 the nonexistence of Ba6LiZ3 can hardly be explained satisfactorily by valence-electron considerations. On the other hand, the consistent atomic-radius ratio, (R/r),* observed for the known A6Bz3-type compounds,3 strongly suggests that the formation of compounds of this type is atomic size-sensitive. Therefore, one is tempted to explain the nonexistence of Ba6LiZ3 entirely on the basis of the atomic-size difference between strontium and barium. However, this approach is not entirely without objection. Atoms are not rigid spheres and are known to vary in size within certain limits.7 Since the atomic-radius difference between strontium and barium (0.07 to 0.09A) is within these limits, it is reasonable to assume that the size difference would have a negligible effect on the formation of Ba6LiZ3. This view is further supported by the fact that the radius ratio, R/r, in other known "size-factor" compounds is observed to range widely—for example, from 1.08 to 1.45 for ABz-type compounds (C15, MgCuz type)' and from 1.37 to 1.58 for AB5-type compounds (D2d, CaZn5 type).g The present investigation was undertaken in order to find a more satisfactory explanation for the non-existence of Ba6LiZ3 and, consequently, a better understanding of the nature of the A6Bz3-type compound. The primary objectives are to confirm the previous conclusion3 that the A6B23-type compound is indeed a "size-factor" compound and subsequently to determine the atomic-radius ratio range in which the A6Bz3-type compound can exist. In order to achieve these objectives, stoichiometric A6Bz3 alloys, where manganese (B) was alloyed with various lanthanide elements (A), were selected for investigation. The atomic-radius ratios of lanthanide elements with manganese range from 1.26 for Lu/~n to 1.46 for Eu/Mn. This radius ratio range includes and exceeds the range of all previously reported A6Bz3-type compounds—1.32 for Th/Mn' through 1.38 for Sr/Li. Furthermore, the atomic-size difference between successive elements of the lanthanide series in order of atomic number) is of the order of 0.01A (europium and ytterbium are exceptions). The series of lanthanon-manganese alloy systems is ideally suited to a precise determination of the limits of allowable atomic-radius ratio for A6Bz3-type compound formation. EXPERIMENTAL PROCEDURE The lanthanide metals, in ingot form, supplied by Michigan Chemical Corp. (St. Louis, Mich.) and Nuclear Corp. of America (Burbank, Calif.), were guaranteed by the suppliers to be at least 99.9 wt pct pure (traces of silicon, calcium, and other minor constituents present on occasion, not to be more than 0.05 wt pct) as shown by spectrographic analysis. Manganese metal, in polycrystalline form, was redistilled from the commercial, chemically pure grade and was analyzed to be at least 99.95 wt pct pure. In all cases, the atom ratio between the two elements in each charge was A (rare-earth meta1):B (manganese) = 6:23 and a constant weight, 3 g, of

Jan 1, 1965

Jan 1, 1971

INTRODUCTION Besides the European export credit agencies covered in Ted Rides' paper in this Chapter, other agencies are also active (see Appendix) but the most notable for mining projects are The Export-Import Bank of the United States ("US Exim") and the Export Development Corporation ("EDC") of Canada. Mexico's Fomex is basically a short-term trade-finance fund administered by the Central Bank. US Exim This independent agency can provide loans, guarantees, and insurance. Like all export-credit agencies, its mandate is to support the export of goods and services from the US as a means of competing against other countries' products. If a piece of mining equipment can only he made in the US, the US Exim may very well not provide any financial assistance. (It is important not to place the order for any item for which export credit is sought because, once ordered, the situation is no longer competitive in US Exim's eyes.) Direct Credits and financial guarantees ("buyer credits") are commonly in amounts greater than 85 million and for terms longer than six years. An example here is the $48.5 million provided to PT International Nickel Indonesia (see Robert de Gavre's paper in Chapter 12). US Exim usually requires a 15% downpayment and, therefore, finances up to 857 of the goods; less if the US content is lower. The dollar funding can he US prime, London Interbank Offered Rate (LIBOR), or other sources. Exim can fund in either or both of the following ways: 1. Under a US bank Letter of Credit ("L/C") 2. Reimbursement to the buyer/borrower via a US bank account. US Exim will, without charge, issue a preliminary commitment. It will, however, need to approve the various credit agreements and prefers to tie other parallel financings into one loan agreement. US Exim's total commitments are large, up to $5R billion in aggregate under various programs. US Exim has been the world's leader in medium-to long-term minerals project financings/ co-financings but suffers from (i) aggressive foreign export-credit competition whereby other nations mix in soft-loans or aid programs ("mixed credits") to increase the percentage financed and lower the interest margin and (ii) an imbalance in its own cost of funds. A common US Exim package would be as follows: 15% Banks under US Exim guarantee, floating rate over prime or LIBOR. 35% US Exim funding, fixed rate 35% Pefco funding, fixed rate 857 Drawn down pro-rata under US bank L/C 15% Cash down payment (may have been financed within a project/corporate credit) 100% Repayment usually begins six months after planned start-up in equal semi-annual instalments, with the banks usually paid out first, Pefco next, and US Exim last. Medium-term credits ("supplier credits") are issued for US equipment exports for terms up to five years, again for 85% of the equipment costs although the exporter is expected to bear at least 10% out of that 857 for its own risk. The buyer is required to be a first-class credit such as some governments or highly credit-worthy companies. Otherwise a bank L/C would be required. (This may be wrapped into an overall project-finance package for a minerals development. The project-finance banks provide an L/C to US Exim instead of funding that portion themselves.) US Exim guarantees 100% of the political risk and either 85% or 95% of the commercial risk for

Jan 1, 1985

By H. J. Fraser

LIKE a runner catching his second wind, the mining geologist in 1944 has had some opportunity to appraise the result of three years of active and intense search for the metallic sinews of war and peace. The war period has been one of physical activity and accumulation of new data but has not so far resulted in the announcement of any profound or revolutionary theoretical concepts or techniques. Most technical publications during the year have been either descriptive or statistical. A review of accomplishments during the war years, although affording some measure of satisfaction in individual cases or regarding production of certain metals or' ores, is far from justifying any feeling of complacency regarding the growth of the profession either in fundamental knowledge or in application. During 1944 an abundant supply of all metals and minerals flowed steadily to smelters and fabricating plants. Also, during this and preceding years, adequate stock piles for war needs, in view of the improved foreign and domestic supply situation, were accumulated in many metals in such quantities that the mining industry has become concerned not with the problem of supply but with the effect these accumulated stocks, if maintained, might have on the postwar market. These considerations culminated in the enactment by Congress of the Surplus Disposal Act, which, admittedly a tempo-

Jan 1, 1945

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

INTRODUCTION IN the iron-cobalt system there are several property-composition relationships of theoretical importance. The alloys are ferromagnetic exhibiting a maximum saturation at approximately 33 at. pct cobalt;1 the interatomic distances at room temperature show large positive deviations from Vegard's rule;2 and in the region of 50 at. pct cobalt there is an order-disorder transition which has a large effect on other properties. The thermal expansion data for the system have been reported3,4.5,6 only from room temperature to 100°C, and for this temperature range a minimum in coefficient in the region of 50 at. pct cobalt is well established. 3,4,6 This paper reports the expansion properties in the iron-cobalt system for temperatures from 30 to 850°C, shows the correlation with other physical properties, and proposes an explanation for the interrelation. EXPERIMENTAL PROCEDURE The thermal expansivities of iron-cobalt alloys in 10 pct steps in composition were determined from 30 to about 850°C. The major series of alloys was prepared by induction melting from Armco iron and cobalt rondelles with the addition of about 0.6 wt pct manganese. This series was supplemented by three compositions: high purity electrolytic iron, high purity electrolytic cobalt, and an alloy of 52.1 wt pct cobalt prepared from the high purity electrolytic iron and electrolytic cobalt by vacuum-melting. The compositions of both series of alloys are given in Table I. The specimens for measurement were prepared from the cast ingots by first hot-swaging followed in most instances by cold-swaging to 0.180-in. diam rod. Some alloys in the region of 50 pct cobalt, because of inherent cold-brittleness, were swaged hot to the final diameter. The expansion specimens were approximately 2 ½ in. long with flat-ground and polished ends. Before measurement they were annealed in hydrogen for r hr at 900°C. In the apparatus used for the thermal expansivity measurements (Fig I), a modification of that designed by Hidnert and Sweeney,7 the differential expansion between the specimen and vitreous silica was measured by a dial micrometer reading to 0.001 mm. An invar fixture supported the dial gauge, and this fixture, in turn, was connected to a split invar collar which supported the outer silica tube. A pyrex "T" was placed over the outer silica tube and was sealed to the invar collar by Apiezon Q sealing compound. A movable hollow vitreous silica rod which rested on top of the test specimen slid through a flexible rubber diaphragm cemented to the top of the pyrex "T." The specimen rested on a vitreous silica pedestal fused into the outer tube and was kept centered by a silica sleeve. A non-oxidizing atmosphere was obtained by admitting hydrogen into the

Jan 1, 1948

By Robert Linton

THE PURCHASE of silver by the United States Government under the provisions of the Pittman Act is practically completed. Producers of silver in this country will now have to market their silver in competition with the rest of the world. It therefore becomes of interest to study such data as are available and endeavor to obtain such suggestions as may be afforded therefrom as to the probable future market position of the metal. Conditions influencing the marketing of silver are numerous and complex. It is a commodity entering. into the arts and manufactures, and therefore influenced by the condition of various lines of business which make use of it; it is currency-being used by all countries for subsidiary coins and even as the founda-tion of the system by a very few; and it serves as a frequent basis for speculation. The various factors involved can easily set up so many cross-currents in the flow of the metal that predictions in regard to the market position of silver can never be safely made, although it may be possible to form some idea of prob-able trends over a sufficiently long period. Of course price is determined, as is the case with all commodities, by the inexorable workings of the law of supply and demand.

Jan 6, 1923