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By Sir Albert E. Kitson

The manganese ore deposits of the Gold Coast, British West Africa, occur in very ancient rocks, of both sedimentary and metamorphic types. In certain respects they have a strong resemblance to those of India and Brazil, as contrasted with those of Tertiary age in Georgia, but in this paper no careful comparison with them can be made. Viewed from the present condition of the manganiferous rocks, the oldest deposits are in the sediments. Later than these are the progressively metamorphosed representatives of these sediments. Youngest are the products of decay and degradation with the concentration of manganese oxide in the rocks of both groups. The oldest occurrences are in argillaceous and siliceous phyllites and slates, which show only a moderate degree of metamorphism. They belong to a series which also includes mudstones, sandstones, grits, conglomerates and subordinate limestones, with tuffs and lava-flows, largely of basic types. This has been named the Birrim System. Its age is unknown, for no definite fossils have been discovered in it. Since these non-fossiliferous strata at many plaees are of a character which in many parts of the world are suitable for the preservation of fossils, and which contain them, it is assumed that the Gold Coast deposits are pre-Cambrian. These rocks of the Birrim System have normally a northeast-southwest strike, and are folded, but not to any very great degree except in certain belts. From the Eastern Province of the Gold Coast they may be traversed diagonally across their strike for upwards of 600 miles, to the extreme northwestern corner of the Northern Territories. Thence they probably extend much farther into French territory.

Jan 1, 1927

By N. O. Taylor

THE failure, by swelling, of several cast aluminum-zinc, spiral, pump rods, used to circulate water in a constant-temperature bath, brought up the question as to whether the presence of tin in varying quantities would have any appreciable influence in controlling this action. Previous workers had found the same difficulty with aluminum-zinc alloys, due to their swelling in water or solutions of electrolyte^.^ It was known that pure aluminum was practically insoluble in concentrated sulfuric and nitric acids, presumably due to the formation of an oxidized film on the surface. Concentrated sulfuric acid had little or no effect on pure zinc and tin and concentrated hydrochloric acid would attack all three metals. These facts aroused curiosity as to the probable reaction of the ternary alloys of these metals, and tests were made to determine their resistivity to the action of common laboratory reagents. Samples, covering the entire range of the ternary series of aluminum, zinc and tin alloys, were made up from good grades of the commercial metals.2 The materials were melted, at as low temperatures as possible, in graphite crucibles in a gas-fired crucible furnace. Graphite crucibles were used in preference to clay, to prevent the absorption of silicon by the aluminum, as found by previous workers. The melted materials were stirred thoroughly with pine sticks in order to ensure complete mixing and the greatest possible freedom from oxidation, and were cast in sectional, iron molds giving bars % in. in diameter and 5 in. long.

Jan 1, 1927

By Orlando E. Romig

As metals and alloys are composed of an aggregate of allotriomorphic crystals or grains, each possessing an individual orientation, the physical characteristics of a metal or an alloy are closely related to the properties of the individual crystals. The preparation and study of single metallic crystals are, therefore, matters of considerable importance. The advent of the X-ray spectrograph as a valuable metallurgical tool has magnified the importance of this subject, because the interpretation of some X-ray spectrographs is difficult unless single crystals are used in these studies. Previous Work The first paper, as far as the writer knows, on the behavior or preparation of single crystals of metals is by Baker.' He describes the behavior of extruded wires of sodium and potassium. These wires, when pulled in tension, instead of showing the usual conical fracture common to most metals, had a chisel-shaped fracture when they were broken. I and 11, Fig. 1, have a similar fracture. Baker checked his results by preparing single crystal wires from molten sodium and potassium and observing their properties. He pre- pared the wires by filling glass tubes, under oil, with the molten metal. The surfaces of the strained wires showed slip bands of remarkable clearness of which photographs are shown in his paper. He concluded that these wires were single crystals and "that the portions of the metal brought into play are cubes. Such cubes, when placed so that a plane through two opposite edges was parallel to the axis of the wire, would allow of lateral contraction by faces gliding over one another in one direction only and not in the direction at right angles."

Jan 1, 1927

By A. W. Hahn

ALTHOUGH enormous tonnages of sulfide lead and lead-silver ores are treated by flotation, the products of flotation mills treating oxidized ores of lead and silver are almost negligible. However, each year there is a slight tonnage increase, and it is possible, should a sizeable oxidized lead ore tonnage be developed, the field will become an important one. In 1918, the Shattuck-Arizona Copper Co. erected a plant at Warren, Ariz., for the treatment of oxidized gold-silver-lead ores. Glenn L. Allen worked out the metallurgy for this plant, employing tabling, followed by flotation concentration. The Shattuck-Denn Mining Co., successors to the Shattuck-Arizona Co., now employs straight flotation in the same mill, treating about 200 tons daily. In 1922, the San Diego mill of the American Smelting & Refining Co., in the Parral district, Chihuahua, Mexico, started operating a 600-ton mill on a mixed sulfide-oxide gold-silver-lead ore. Tables and flotation are used here, and about 200 tons of oxidized slime treated by flotation. In 1923, the Eureka Holly Mining Co. started operating a 90-ton mill at Eureka, Nev., using tables and flotation, on an oxidized lead-silver ore. In 1924, the American Smelting & Refining Co. started a 250-ton mill in northern Peru, to treat a high grade oxidized gold-silver ore with very low lead values. In 1924, the Grand Central Mining Co. started a 200-ton flotation mill on old oxidized gold-silver-lead tailings at Fairbank, Ariz. In 1926, the Compania International Minera, a subsidiary of the Union Corporation of London, started a 250-ton flotation mill on oxidized lead-silver ores, and during April of this year, the Phelps-Dodge Corp. will probably start a 250-ton mill at Warren, Ariz., on oxidized lead-silver ores, similar to those being treated in the Shattuck-Denn mill.

Jan 1, 1927

By Schumacher, Earle E.

THE solidus line above the solid solution field in the lead-antimony system was originally determined by Dean and his associates1 from heating curves. They did not regard this line as having been accurately fixed and in their more recent publications2 the curves drawn do not follow closely the original data. The precise location of the solidus line is of importance in the extrusion of lead-antimony cable sheath, as the temperature of the metal in this process must be less than the lowest temperature at which any part of the alloy in the lead-press charge becomes liquid. It is very desirable, however, to operate at as high a temperature as possible, as the rate of extrusion for a given pressure is approximately doubled for an increase of 10" C. in temperature. The precise location of this line is also important in the investigation of ternary systems of lead, antimony and a third metal. For these reasons, and because of the differences reported in the literature, data were secured on the lead-antimony solidus line by the classical quenching-test procedure.

Jan 1, 1927

By A. C. Fieldner, W. A. Selvig

Ash in coal has always becri regarded as an undesirable substance, as the heat content of a coal dccreases in direct proportion to its ash contcnt. It represents so much inert materid that has to be transported, handled when the coal is burned, and finally disposed of. W. R. Roberts, in an address bcfore the Engineers' Society of Western Pennsylvania, Pittsburgh, on Sept. 29, 1925, said that on an annual output of five hundred rnillion tons of coal, a reduction of 3 per cent. of ash means fifteen million tons of refusc and a decrcase of $30,000,000 in freight charges. Ash also often prevents effieient utilization of the coal through the formation of clinker causcd by the mcltirig of the ash constituents when subjected to heat. The mineral constituents of coal may be of such nature as to make the coal unsuited for speeifie uses as for instance, high-sulfur coal for making metallurgical coke. While the usual proximate analysis of coal gives the amount of ash, it gives no information as to the nature and coniposition of the ash nor of the minera1 constituents from which the ash is produced. For the efficient washing of coal to remove ash-forining constituents it is desirable to know the composition and distribution of the ash-fonning constituents. Obviously such information is also desirable for the most efficient utilization of coal. Nature and Composition of Coal Ash Coal ash may be defined as the inorganic residue remailning after cornplete ignitior of coal. It is dcrived from the mineral constituents of thc coal. The ash-forming constituents may be roughly classified as inherent impurities and extraneous impurities. The former are mixed intimately with the coal substance, and arc derived either from the original coal-forming material or from external sources such as sedimentation and preeipitation while the vegetal coal-forming plant remains accumulated. The latter are present in the coal bed as partings, bands or nodules of pyrite! slate, shale, calcit,e, bone, etc. These are formed either during the laying down of the coal bed, or subsequently. Flag-

Jan 1, 1927

By W. Z. Price

The coal lands that the Nemacolin mine is to develop embrace over 8400 acres; the tract is oblong and its eastern edge is along the Monon-gahela river. As shown in Fig. 1, the mine is divided into two parts (the North mine and the South mine) by a 150-ft. barrier, which however, is cut through at intervals by haulageways. Each part is fed from seven main entries—a loaded track, an empty, a manway, and four return air courses. The loaded tracks converge at the shaft bottom but the empty roads maintain their identity throughout their length. With three intakes and four returns on either side, there is ample room for expansion of air and every facility for ventilating is provided. The four south air courses converge into two, crossing the shaft bottom, and then into one at the south side of the air shaft. The four north air courses converge in a similar manner on the west side of the same shaft. This convergence is accomplished by concrete arched

Jan 1, 1927

By Edmund Davenport

THE specific aim of this work has been to study certain forms of internal deterioration which occur in tungsten filaments when subjected to high temperatures under various conditions, and to determine the cause of such deterioration. This would naturally lead to a consideration of methods of control or means of prevention of the phenomena. The deterioration was first noticed as a peculiar condition in the grain boundaries of certain tungsten filaments which had been burned? for long periods in lamps. In these cases it was noted that the grain boundaries contained a number of minute black dots which were at first thought to be non-metallic inclusions. It was demonstrated later that these dots or pits, as they were designated, could be readily produced by burning filaments in an atmosphere of flowing hydrogen. This method was convenient and adequate for the purpose, and was adopted for most of the work discussed in this paper. The evidence accumulated to date indicates that these pits are actually small voids between the grains. The purpose of this paper is to present- the information on this interesting subject gathered during a period of about 3 years. As applied to tungsten, the subject appears to be of considerable importance, experience having shown that this pitting ?is frequently associated with poor performance of filaments in lamps. The question has arisen as to whether these intergranular pits are peculiar to tungsten, or if they occur in all metals. If they are found iii all metals, the facts will be of considerable theoretical interest, as the material at the grain boundary plays an important part in most of the current theories of the properties of metals and alloys.

Jan 1, 1927

By A. C. Watts

For several years, a mine in Colorado experienced considerable trouble from small fires caused by the blasting of coal. Although a well-known make of permissible powder was used, it was first thought that the powder ignited gas that might be present and that this, in turn, set fire to line brattices or to the coal. Experiments were, therefore, conducted with another make of powder, but the results convinced the superintendent of the mine, Robt. Williams, Jr., that the fires were not caused by the powder but by the high-voltage electric current used for detonating the shots. The mine "makes" gas very freely, giving off from three-fourths to one million cubic feet of methane every 24 hours. The coal is a good grade bituminous of a very free burning quality. Electric shot-firing from the outside, after all men and animals were outside, had been practiced for a number of years. The shooting circuit was connected with the main power circuit at the mouth of each entry. Shooting circuit switches were mounted in boxes, which were kept locked with the handle of the switch, in open position, showing through the bottom of the box. The door of the box could not be shut and locked when the shooting switch was closed. At the entrance to each room, or working place, a small switch, called the miner's switch, was placed on the shooting line. It was the duty of the miner, when entering his place at the beginning of the shift, to see that this switch was open and that it was kept open until he left the placc at the end of the shift to go out of the mine. Grounded return was used for main power lines. The current was 500 volts, direct current, with 100 to 300 amp. The nearest working face was 9600 ft, from the shot-firers' switch outside the mine and the most remote working face was 2½ miles. The various working faces were scattered over a wide area between these two points. A description of the main power line would be valueless; the conductors were of sufficient size, the drop in voltage being not more than

Jan 1, 1927

By John V. W. Reynders

Our entry into the World War suddenly brought home to us in a startling way the vital importance of manganese. Since the war, much has been written and said upon the subject of manganese and a great deal of time and money have been spent in attempts to find an adequate substitute for this metal in the manufacture of steel; none has been found. It is true that ways are known by which it is possible to make small amounts of good steel without manganese, but taking into consideration the diminishing quality of iron ores and fuels as well as the increasing exaction of specifications for finished products, it may safely be assumed that, high-grade manganese ore will be more and more a necessity in the production of steel as time goes on. Taking world resources as a whole it may be well to point out that the problem of obtaining needed supplies of manganese from a strictly commercial viewpoint is now less serious than it was before the war. Formerly it was feared that world resources of high-grade manganese ore might be exhausted in a relatively short time, but, largely as a result of the stress laid upon the importance of manganese during the war, the world's available supply of high-grade manganese ore has been greatly augmented by new discoveries and fuller development of previously known deposits. Sources of Production Russia alone, of countries producing the major part of the world's stee1, has within its geographical boundaries sufficient manganese to supply its needs. The domestic production of England is inadequate and English requirements for high-grade manganese are supplied principally from India. France also draws largely upon India, as it depends upon foreign sources of supply except with respect to a small tonnage of silico-manga-nese and silico-spiegel produced in the Hautes-Pyrénées. Germany and the United States likewise depend upon foreign sources of high-grade ore, though each possesses comparatively large reserves of ferruginous manganese ore and manganiferous iron ore. At present the world demand for high-grade manganese ore is met with ease by the production of Russia, India, Gold Coast and Brazil.

Jan 1, 1927

By F. Julius Fohs

A comparative balance sheet for 1924 and 1925 follows: 1925 1924 Barrels Barrels Gross production..................................... 763,000,000 714,000,000 Imports of crude oil.................................. 62,005,000 77,776,000 Imports of refined oil................................. 16,263,000 16,470,000 Total......................................... 841,268,000 808,246,000 Surplus supply....................................... 25,000,000 30,246,000 Indicated domestic demand........................... 704,465,000 667,000,000 Exports crude oil.................................... 13,353,000 17,913,000 Exports of refined oil................................. 98,450,000 93,087,000 Total......................................... 816,268,000 778,000,000 Stocks, Dec. 31 (crude 410,654,000).................... 538,000,000 513,000,000 These figures show an increase of 49,000,000 bbl. in production and little change in oil imported; 37,000,000 bbl. greater apparent domestic consumption and actually greater utility in consumption, due to increased gasoline production by cracking; and 1,000,000 bbl. more crude and refined oil exported in 1925 than 1924, representing a total apparent increased demand of 38,000,000 bbl. The excess of demand over supply in 1925 was 25,000,000 bbl. The increase of stocks over those at the close of 1924 was 25,000,000 bbl. Of the stocks on hand at the close of 1925, about 82,000,000 bbl. in California were not refinable. Imports from Mexico and South America It would not be surprising if, by 1930, we should actually welcome the imports from Mexico, Venezuela, Colombia, Peru, Argentina and Trinidad. If these States produce 155,000,000 bbl. and use, perhaps, 30,000,-

Jan 1, 1927

A Page Adam. H. F. and Ruggles! G. H., Results with Xanthate at Inspiration............. 337 Adnic proertiea of....................... 474 Africa; Gold Coast, manganese...........abs.474 191 mining districts......................... 254 Aid, H., biography........................ 154 Air compressors. In flotation................ 45 Air-gas lift: gae-oil ratios relation of......abs. 475 Gulf Coast. mechanical installations... .abs. 475 Seminole field........................abs. 476 Air-sand process. cleaning coal............abs. 89 Alabema, Birmingham district. drainage. . abs. 86 " Alclad." aluminum alloy................. 395 Alexander. W. Homer. biomaphy .......... 37 Allen. Andrews. Preparing Coal after Mechanical Loaders......:....T................. 181 Allison. F. H., Comparison of the Effect of Nickel and Cobalt in Steel.............aha. 151 Alloys: See Metals named. Aluminum: heat treatment...............abs. 444 machining...........................abs. 443 Norway............................... *465 Aluminum alloys: " Alclad "................ 395 application of........................abs. 443 deformation..........................abs. 150 Aluminum Bronze Manufacturers Institute. organized.............................. 188 "Alumnum. The Metal and Its Alloys." B.R. 42 Aluminum-iron-silicon alloys, equilibrium relations.............................aba. 444 Aluminum-manganese alloys, equilibrium relations in..........................aba. 87 Aluminum-silicon alloys. heat treatment. .abs. 398 American Association of Petroleum Geologists. annual meeting................... 81 American engineers. war memorial.......... 499 American Institute of Mining and Metallurgical Engineers: Committees: Douglas. James, medal...... 324 Geophysical Prospecting............. E. 204 Mining Medal........................ 324 Nominating: Election................. 235 report............................. 479 Constitution. votes for.................E. 494 Constitution and By-laws. draft of....... 374 Directors: Minutes of meeting.....110. 235. 323 publications.......................... 523 Directors adopt badge................... 324 Dues. increasing........................ 111 Dues are Due.......................... 236 Institute of Metals Division: annual lecture............................ 187 data sheets.......................... 187 Detroit meeting, (September). . .307. 353, 440 lecturer C. H. Desch................. 15 Local Section Committee. members..... 187 New York meeting (February)......... 115 Research Committee.................. 187 research problems..................... 6 Local Sections: Arizona............................. 365 Boston, meetings................40, 197. 486 Page American Institute of Mining and Metallurgical Engineers—Continued Chicago, meetings...40, 94, 156, 196,240,417 Chicago and St. Louis, joint meeting, Danville....................... 486, 527 Colorado, annual meeting.............. 285 Columbia, meetings 39, 93, 156, 196, 238, 286, 327, 365, 486, 527 El Paso, organized.................... 238 Fort Worth, organization meeting...... 485 Joplin-Miami Zinc, meeting.......... 286 Lehigh Valley: annual meeting......... 197 meetings...................... 239, 527 Los Angeles, meeting.................. 285 Mid-Continent, meeting............... 156 Minnesota, annual meeting............ 326 Montana, meeting.................... 40 New York, meetings................240, 284 North Pacific: meetings.... 39, 157, 197, 527 Fieldner, A. C, speaker............. 486 resolution.......................... 439 Oregon, officers....................... 196 Pittsburgh: meetings........... 156, 327, 526 mine transportation conference....... 485 St. Louis and Chicago, joint meeting, Danville........................... 486 San Francisco, meetings............... 92, 197, 239, 285, 439, 486, 527 Southern California, meetings 40, 157,197,283 Upper Peninsula, meeting.............. 486 Utah, meetings..........40, 93, 156, 239, 365 Washington, D. C, meetings 40, 93, 365, 528 Medals: Douglas, James................34, *84 Fritz, John, award, 1928.............. 480 Johnson, J. E., awarded T. L. Joseph... 83 Saunders, William Lawrence........... 34 meetings: Cleveland, April, 1927.......166, 207 Detroit, Sept., 1927............307, 353, 440 Fort Worth, Oct., 1927.........307, 353, 471 • future............................. E. 102 Knoxville, Nov., 1927.............. 480, 500 New York, Feb., 1927, announcements, programs, etc.................33, 50, *106 Salt Lake City, Aug...............306, *422 Members and jobs...................... 477 Membership, benefits.................8, E. 2 Officers and directors.................... *122 Open-hearth Conference................. 282 Petroleum Division: activities............ 186 annual meeting...................... . Fort Worth meeting............307. 353 471 luncheon............................ 91 New York Petroleum Club, officers..... 110 nominations........................23. 519 officers.............................. 117 President's trip. May.................281. 398 Publications: Directors discuss............ 523 Institute of Metals Division Volume... . 178 Petroleum Volume.................... 192 Technical Publications...........E. 294 323 Transactions. Vol. LXXIV. LXXV....00. 524 Review of the year.........:........... ...E. 104 Stockholders. report to..............E. 49

Jan 1, 1927

By A. E. Wells

In this paper are described various comparative tests made on cracked and straight run gasolines. The results of these tests may be briefly summarized as follows: Samples of 54 to 55° Bé. gravity cracked gasolines, with end point of about 442° F., and with a somewhat larger proportion of the less volatile fractions than conformable to government specifications, were used in a single cylinder variable compression engine under the same conditions as were samples of straight run gasoline of 58 to 59° Bé. gravity, and of which one had a greater proportion of the more volatile fractions than called for in government specifications. The cracked gasolines showed decidedly less tendency to knock, hence could be used at higher compression ratios and thereby developed from 10 to 20 per cent. more power than did the straight run gasolines. These figures may be taken as one measure of the superiority of the cracked gasolines under test with the straight run gasolines. It is not claimed that all cracked gasolines are superior to all straight run gasolines to the extent indicated by the above tests; cracked gasolines vary as do the straight run products. Cross's work and that of others have indicated that certain cracked products may have a much greater superiority over straight run than that determined above. From various sources and by different methods of testing data are being obtained to show the definite and generally quite considerable superiority, as an anti-Cetonating fuel of cracked gasolines over straight run gasolines. It is now becoming generally recognized that by increasing the production of cracked gasoline motor fuel from those heavier petroleum fractions, which otherwise would be used for burning purposes, the petroleum industry is not only working in the interest of the conservation of the world's supply of petroleum, but is at the same time making available to the gasoline-consuming public a product distinctly superior to the straight run gasolines.

Jan 1, 1927

By Richard W. Smith

There are three distinct varieties of phosphate rock, in Tennessee, known commercially as: (a) the "brown" rock, which is the residual product of the weathering and natural concentration of certain phosphatic Ordovician limestones; (b) the "blue" rock, which is an unaltered phosphatic stratum of Mississippian or Devonian age; and (c) the "white" rock, which is the result of chemical replacement and deposition. Before 1894, South Carolina and Florida had supplied most of the phosphate of the United States, South Carolina leading until that date and Florida from then until the present time. In December, 1893, the blue phosphate of Tennessee was discovered almost simultaneously on Swan Creek, in Lewis County, by two independent parties—by one as the result of a careful and systematic search for a workable deposit of the long known kidney phosphate, and by the other through mistaking it for a "bloom" of coal. Leases were taken and, with further prospecting disclosing other deposits in the region, the development progressed as rapidly as could be expected without railroad transportation. In January, 1896, Judge S. Q. Weatherly, who was interested in the development of the blue phosphate, while riding along the road south of Mt. Pleasant, noticed some slabs of a brown rock in place above the limestone. He took samples, and had them analyzed, thus discovering the high-grade brown phosphate of this district. This discovery was kept a secret until July, 1896, when mining was started at the village of Mt. Pleasant. Development proceeded rapidly, many owners obtaining their capital by the sale of their rock fences, which were largely composed of slabs of high-grade brown phosphate. The development of the brown rock, which is richer and more easily mined than the blue, caused Tennessee to advance from a poor third in production to second, surpassing the output of South Carolina, and being excelled only by Florida.

Jan 1, 1927

By Ancel St. John

During a session on coal and coke at the February, 1926, meeting of the American Institute of Mining and Metallurgical Engineers, the writer called attention to the important work on the X-ray analysis of coal1,2 being carried on in England by C. Norman Kemp and his associates. This aroused so much interest that a paper on the subject was requested for the October meeting. It has seemed advisable to make this paper a preliminary survey of the present status in the application of X-ray methods to coal problems and to follow it from time to time with further articles as the art develops. A survey of this sort naturally divides itself into two parts, radio-scopic analysis of the distribution of constituents through the body of the coal, and diffraction analysis of the state of association of the elementary components. In this article the subject matter concerning radioscopic analysis has been drawn almost entirely from the writings of Kemp and his associates and the illustrations have been sptcially furnished by him. It is a pleasure to record here a great indebtedness for this courtesy and cooperation. The subject matter and illustrations concerning diffraction analysis are taken from the author's unpublished researches. Nature and Properties of X-rays Before proceeding it is well to recall the nature and some of the properties of X-rays, as well as our present conception of atomic structure According to the accepted theory atoms are composed of electrically-charged particles. A positively-charged center, called the nucleus,

Jan 1, 1927

By J. C. Bradley

The relation of annealing temperature to conductivity of copper wire has been determined. Conductivity hard was 98.26 per cent. After a 10-min. heat,ing at 200" C. it was 98.69. By annealing 10 min. at 300" C. a large increase, to 100.93, occurred. Maximum conductivity, 101.15, was attained after a 500" C. anneal; thereafter it decreased to 100.53 after a 950" C. anneal. If copper is gassed the decrease is much more than this. Material and Method The work was done on high grade electrolytic copper, 99.942 per cent, copper plus silver, silver 0.0008 per cent. It was hot-rolled to 1/4 in., then cold drawn to 0.080 in. The wire was cut into 25 5-ft. lengths and numbered 1 to 25 as cut. Four samples were tested hard. The others were wound into 5-in. diameter coils. For the 100" C. heating a coil was put into water, the water brought to . boiling, and the wire kept at this temperature for 10 min. For the higher temperatures the coils were placed in envelopes of sheet copper, a little water added, and the envelopes sealed by folding over the edges twice, and hammering them together. This kept the air out very well. The envelope and wire were brought to the desired temperature; this was maintained for 10 min., then the whole was water-quenched. Results Data from the tests are shown in the table and plot (see Fig. 1); conductivity is referred to the International Annealed Copper Standard at 20" C. Conductivity hard is considerably less than conductivity soft.1 The increase is sharp when the wire anneals. The maximum, 101.15 per cent, in the particular material used, comes at 500º C.; thereafter the conductivity falls to 100.53 per cent. after 950" C. annealing, a drop of 0.62 per cent.

Jan 1, 1927

By W. L. Zeigler

The mill is a departure from gravity concentration and has gained a reputation for the low initial cost of erection, extreme simplicity and the low cost of milling on the refractory character of the ore which is treated. The structure is of heavy timbers with board walls and corrugated roofing. The floors are concrete and the general layout is of the ground floor only. All the machines are driven by individual motors and the transmission usually found in such a plant is entirely absent. (Fig. 2.) ORE The ore from the Galena mine is sheared Wallace quartzite replaced with quartz, siderite, pyrite, sphalerite, gray copper (tetrahedrite) and very fine-grained argentiferous galena. Much of the silver is undoubtedly associated with the gray copper, the amount, however, apparently varies with different localities in the vein. An average assay of the ore is 6.0 per cent. lead, 1.3 per cent. zinc, 0.3 per cent. copper, 17.5 per cent. iron and 4.5 oz. silver. The concentrates produced are of an average 53 per cent. lead, 40 oz. silver, 8 per cent. zinc and 11 per cent. iron, while the tailings are 0.5 per cent. lead, 0.4 oz. silver. With the present market for zinc no attempt is made to produce a zinc concentrate.

Jan 1, 1927

By W. Spencer Reid

ALTHOUGH there have been some developments during the last five years which have had far- reaching and important bearing on lead smelting, it cannot be said that any basic principles of pyrometal-lurgy have been discovered. Eighteen or twenty years ago the Dwight & Lloyd sintering machine was intro-duced and literally turned the roasting end of lead smelting upside down. There has been nothing com-parable to the advent of the sintering machine during recent years. Actual blast-furnace practice today is slightly, if any, better than it was five years ago ; although immeas-urably better than it was twenty to thirty years ago. Some tell us that as far as cleanness of slags is con-cerned, it is no better today than in the days of the old Romans. The metallurgist of a generation ago did very good work, considering the equipment he had available. It is true he was working with the cream of the ores, the clean oxides and carbonates and the low-zinc sul-fides. He was troubled very little with high zinc and selected his type of slag according to preference of -some authority such as Eilers, Iles, Raht, Hahn, etc. As these free-smelting ores were depleted the complex ores were encountered, and the metallurgist gradually discovered that he had to forget the old type slags and run a slag according to the percentage of zinc on the charge. I believe it is now universally agreed that SiO2 and CaO must be lowered and FeO raised in a slag as the ZnO increases. The ratio of these variations is practically uniform and can be relied upon over wide fluctuations of the determining element, zinc. These "bastard" slags, as they are sometimes inappropriately designated, are actually in daily use, and the metallurgist of today has been forced to adopt certain standards, as a guide to successful operation. These slags practically refute the old Eilers' theory that all good slags are chemical combinations of SiO2 with FeO and MnO, and CaO and MgO. Eilers' and the other type-slag theories were based upon the assumption that a good slag must con-form to a definite formula, such as 3 (FeO)2 SiO2 + 2 (CaO)2 SiO2 or 2 (FeO)2 SiO2 + 2 (CaO)2 SiO2 which respectively figure 31.3 and 36 per cent SiO2. The SiO2 was supposed to remain constant even with the entrance of impurities such as Zn and A1,0? into the slag. The increasing amount of impurities, espe-cially Zn, soon discredited the theory, for in actual practice the slag failed to run freely.

Jan 1, 1927

By R. M. Caitlin

QUITE a number of years ago in looking for basic facts, it seemed obvious, in view of an unquestion-able supply of raw material and an extensive requirement probable in the near future, that the funda-mental requirement of any shale-oil industry was mass production 'by a continuous process. This decision greatly simplified matters, as it eliminated all considera-tion of externally-heated retorts, and all batch processes, which only utilize a part of the capacity of the interior space because, unless the ashes are removed as rapidly as formed, the space occupied by them is dead, instead of being occupied either by shale in active distillation or in drying out and heating up preparatory thereto. A second imperative and basic necessity soon appeared as a natural sequence, namely, the fixed carbon of the spent shale must be utilized to supply the heat for the eduction of the oil. PRODUCTION OF THE CRUDE As the production of the crude oil is the first and most important step in the utilization of oil-shale, being the only source from which the multitude of possible by-products can come, each by a special treatment of the crude oil, I will devote the time allotted to me to the subject of crude oil production-its cost expressed in terms of tons treated per man per shift. The costs of mining the shale and refining the crude shale oil vary with local conditions and are not specially influenced by the source of the crude. But the cost of distilling the shale in terms of tons per man shift seems to be the basis of any proper comparison of costs. After considerable experimenting, ranging from laboratory tests up to and including quantities of fifteen to twenty tons, it was evident that a plant might be made up of an indefinite number of units operating in concert. The economic size of the units, however, would .have to be determined by experiment. The general theory of our process contemplates a regulated combus-tion of the fixed carbon in the spent shale, in its incan-descent condition after all the oil has been driven out of it; and a transfer of the resultant heat to the mass of raw shale above.

Jan 1, 1927

Page Foreword—H. Foster Bain........................ 9 Letter of Transmittal—F. Julius Fohs...................11

Jan 1, 1927