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By Williams, J. A.

THE Alaska Juneau mine has been developed through an adit driven at the elevation of the top of the mill and all mining is done above this main haulage level. As a result of wholesa1e"mining operations about 11,000 tons rock containing one dollar' per ton in gold is, hauled to the. concentrator during every 24 hr. Due to the method of mining, whereby a system of oreways delivers-the.ore direct from the stope to the bottom level of the mine, no tramming of ore is done on any of the upper levels. However, ;in doing exploratory drifting and crosscutting on the upper levels, the broken material is trammed by hand in 1-ton 18-in. gage cars to a nearby raise connecting with one of the several oreways. This constitutes the only tramming operation except that on the main level.

Jan 1, 1931

By Nathaniel Arbiter

There is a history in all men's lives, Figuring the nature of the times deceas'd, The which observ'd, a man may prophesy, With a near aim, of the main chance of things. W. Shakespeare, Henry IV; Part 2 Introduction This nation's first century embraced two stages of the Industrial Revolution. During one, what had been a colonial agricultural economy began to industrialize; water power, then steam after 1794, were the energy sources; coal and iron were the essential ingredients. The second stage started after 1850; aided by rich and diverse mineral resources, the country began its transition from the Iron Age to the Age of Metals. Early civilizations had been built on stone, and fairly high levels were sustained on iron. But the spectacular advances in the past century in communication, in construction, in transportation by sea, rail, land and air, and in much that characterizes modern civilization have depended increasingly on the use of the complete metallic and nonmetallic resources of the earth's crust. Thus it was appropriate to define the Industrial Revolution as “the period during which man's relationship to natural resources became utterly changed”, 1 with minerals playing a major and indispensable role. But we are now becoming aware that the relationship of man to natural resources must change again. On every hand the dangers inherent in the contamination of land, sea and air by the wastes of civilization are becoming apparent. And from the growing realization that mineral wealth is finite must eventually come other far reaching changes in mineral use and distribution. For on the scale of centuries we cannot continue to exploit mineral resources even at present rates, let alone at expanded rates, without eventual depletion of the more abundant resources, and early exhaustion of the less abundant. In the past our problems were relatively easily met by the development of new and improved machinery and processes. But the future will

Jan 1, 1971

The curve of Fig. 3 for pyrite requires modification. There 11% a range of pH values from 6.2 to 7.8 for which no cyanide is required to prevent contact. From 7.8 to 11.3 a small amount of cyanide is required, with a sharp maximum of 20 mg. per liter at pH=9.6. The mistake arose from considering too few solution compositions (17 were considered) in constructing the curve. Subsequent work with other collectors indicates that the corrected curve is typical for such systems; it illustrates the further development of the dip in the pyrite curve of Fig. 5.

Jan 1, 1938

Alexander Forsyth, Southport, Me. (communication to the Secretary): In Mr. Irving's able and interesting paper he describes minutely the appearance of the wolframite and its association with the refractory siliceous gold-ore. He also describes this gold-ore, but fails to mention the important pockets of metallic gold found in the Lead City occurrence of it. I use the term " metallic " in preference to the more usual " free," for it has been found that this gold is not easily amalgamated. Metallic gold is comparatively rare in the refractory siliceous gold-ores of the Black Hills; hence its occurrence in considerable amounts in the Lead City wolframite district deserves notice. I possess a beautiful specimen from the Harrison mine. It is a lump of drusy, granular ore, about 6 in. in diameter. The gold .is " shot" through it in large and small pin-heads; and in two specially oxidized areas, each about 11/2 in. in diameter, it is peppered full. The famous " Grantz strike," made in the Lead City wolframite locality, produced many beautiful gold specimens. This district affords an excellent example of the repeated discovery of new mineral values upon old ground. By reason of its proximity to the Homestake vein, this wolframite deposit was inevitably traversed many times by experienced geologists, mineralogists and mining engineers, who evidently must have thrown aside, with no thought of wolframite, the lumps of " black iron " lying about. I have the admission of an able geologist that, six months before the wolframite was discovered, he visited some of the very mines where it occurred, and passed it by as magnetic iron-ore. At the time of the discovery, the mineral was scattered over the gold-mine dumps in no small quantities, having been culled as worthless out of the gold-ore. It remained for

Jan 1, 1902

By H. O. Hofman

With the exception of the exhaustive paper on the Father de Smet mill, by its designer, Mr. A. J. Bowie, Jr. (Bans., x. 87), nothing, so far as the writer is aware, has as yet appeared on the stamp-mills of the Black Hills of Dakota, although they have been steady producers for the last ten years. Within the small area of about 6000 by 1600 feet, $2,271,341.14 was produced in 1887† from rock averaging $4 per ton in free gold. I. The Ores. Character of the Ores.—The gold of the district is found in quartz and pyrites finely distributed through vast bodies of mica- and amphibole-schists, argillites and phyllites, and also impregnating the schists themselves. The " Belt," embracing the section of Lead City, Terraville and Central City, is the only part worked at present. The principal associated mineral is iron pyrites, with some arsenopyrite and chalcopyrite, garnet and asbestos. The ores from open cuts and upper levels are more free-milling. than those from underground workings below water-line. Hence

Jan 1, 1889

By L. B. Herring, Harold Decker

The area under discussion includes districts 2 and 4, so designated by the Texas Railroad Commission,‡ and comprises the following 26 counties: Bee, Brooks, Calhoun, Cameron, De Witt, Duval, Goliad, Gonzales, Hidalgo, Jackson, Jim Hogg, Jim Wells, Karnes, Kenedy, Kleburg, Lavaca, Live Oak, Nueces, Refu-gio, San Patricia, Starr, Victoria, Webb, Willacy, Wilson and Zapata. Drilling and Production The total number of wells drilled in this district during 1944 is shown in Table 5. This indicates a 41 per cent increase in all drilling over 1943. In spite of every handicap created by the war, the oil industry more than met the crisis in its drilling program in this district. Last year we thought it would be impossible to add to the total number of wells drilled in the previous yea;, but in spite of the lack of manpower and materials this large increase was shown. During 1944 this district produced 124,201,978 bbl. of oil from 11,607 producing wells, whereas in 1943 it produced 88,421,693 bbl. from 11,211 producing wells. This is an increase of 35,780,285 bbl. of oil. Some decline has been shown in the older fields arid undoubtedly the majority of wells in the district are producing at too high a rate. However, this district has been able to meet any demands made on it by the Petroleum Administration for War for increased production. Discoveries and Extensions There was a slight decline over the preceding year in the number of wildcats drilled, but the number of discoveries increased. In most instances subsequent development has not been sufficient to arrive at preliminary valuations but it appears that the over-all oil discoveries were below normal and that the gas discovcrics were relatively more important. The Canolis and Tijerina pools, Jim Wells County, and the Dan Sullivan pool, Brooks County, appear to be the outstanding oil discoveries of the year. No important oil reserve was discovered or developed in the Wilcox horizons, although considerable wildcatting was done. Important extensions were made at Agua Dulce and Stratton in Nueces and Teleberg Counties. Production was increased appreciably at Willimar, Willacy County, and Seeligson, Jim Wells County, in sands and areas which were apparently productive at the beginning of the year. Refining Most of the major work in the changing and completing of refineries was finished this past year. Some of the most modern refineries in the industry are now located in the Corpus Christi area. Gas and Condensate No new recycling projects were commenced during the year, nor were there any important additions to the old operations. No major gas reserve was developed, although several new discoveries suggest potentid possibilities.

Jan 1, 1945

By Frank Rieber

THE discovery that strongly magnetic bodies localized near the surface of the earth could be detected by the distortion which they produced in the resultant magnetic field marked the beginning of magnetic surveying methods. From an original ability to detect bodies of magnetic iron ore and the like when located very close to the, surface, these methods have been extended until today they promise to give much information with regard to the structure of such slightly magnetic material as sedimentary rock containing only a very small proportion of iron.1 The recent extensions have been made possible through the development of more delicate instruments, and of methods for their use. From the original compass and dip needle, the design of apparatus has progressed until equipment Is typified by magnetic balances capable of measuring the components of the earth's field to an extremely high degree of accuracy. It seems unlikely that the limit of such instrumental development has been reached. Just as the change from compass and dip needle has enabled the location of relatively minor changes in magnetic materials, so additional developments in the direction of increased sensitivity, as well as in greater dependability and constancy of operation, should reveal positively many slight changes which either escape notice in the present surveys or are so small that they cannot with certainty be separated from uncontrollable errors due to inconstant operation of the equipment. The ability to read smaller and smaller variations does not mean, of course, that deductions as to the causes of these variations will be made as accurately and definitely as -is possible with the more pronounced anomalies.

Jan 1, 1928

By R. E. Somers

1. INTRODUCTION 1. Location, Topography, and Climate The Burro Mountains are located in the southwestern part of New Mexico, in Grant County. The group is made up of two distinct moun-tain masses, known as the Little Burros and the Big Burros, the former lying about 6 miles southwest of Silver City-, and the latter about 9 miles farther in the same direction. They are separated by the valley of the Mangas River, a tributary of the Gila, and a stream only in name, except after a heavy down-pour of rain. . The Little Burros attain an elevation of 6,625 ft. above sea level, and the Big Burros 8,054 ft., with the surrounding country averaging about 6,000 ft. To the south of these mountains stretches the desert plain, while to the north are the more frequent elevations of the mountainous country.

Jan 5, 1915

By Kenneth Seaver

Discussion of the paper of KENNETH SEAVER presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 105, September, 1915, pp. 1913 .to 1927. J. W. RICHARDS, South Bethlehem, Pa.-This paper concerns a very large industry, and an important detail in that industry. Within sight of where I live in Bethlehem, Pa., are coke works in which $2,500,000 was lost by the use of improper bricks in the coke ovens. This was the fundamental reason of the failure of the plant. The old ovens have all been torn out and replaced by new ovens built of proper bricks. This may emphasize the commercial importance of this subject. When speaking about coke-oven brick, the first thing that comes to my mind is how important it would he if it were possible to. get a brick of better heat conductivity. The heat for coking coal has to go through the thickness of the brick. The silica brick used has low heat conductivity as compared with some other refractories; magnesite brick probably has four times its heat conductivity. The coke oven needs bricks of high heat conductivity. Any process which would increase the heat conductivity of silica brick would undoubtedly shorten the coking process.

Jan 12, 1915

By AIME AIME

SILVER reached a new high, with the ceiling the limit, at the annual Institute dinner at the Commodore on Washington's Birthday night. Carrying along as ballast other commodities, such as rolls, roses and ferns, souvenir boxes and table number placards, hundreds of silvery balloons, cut loose from their moorings at the tables, bounced idly against the plaster decorations high overhead. At the head table, Scott Turner, retiring President, pre- sided as toastmaster, with the new President, Frederick M. Becket, on his right, and the Chairman of the New York Section, Sydney H. Ball, on his left. Many other distinguished Institute members, medalists, and representatives of organizations and committees, ranged to the east and west. Each had the opportunity at least to rise and bow.

Jan 1, 1933

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members who registered at Institute headquarters during July and August : R. H. Sweetser, Columbus, Ohio. C. R. Hill, New York, N. Y. Raymond Brooks, Goldfield, Nev. H. A. Morrison, Candor, N. C. Edward M. Shepard, Springfield, Mo. Frederick J. Patchell, Washington, D. C. Rudolf Gahl, Clifton, Ariz. Walter F. Pyne, New York, N. Y. Edmund von Maltitz, Pittsburg, Pa. Harvey B. Small, Mangangue, Colombia, S. A. M. K. Rodgers, Seattle, Wash. M. B. Cohen, Miami, Ariz. J. F. Erdlets, Jr., New York, N. Y. A. P. Watt, Newark, N. J. D. H. Ladd, Houghton, Mich. H. H. Stoek, Urbana, Ill. Roy F. Cornell, Santa Cruz, Cal. D. W. Brunton, Denver, Colo. W. B. Foote, Geneva, N. Y. C. S. Robinson, Youngstown, O. H. Sjogren, Stockholm, Sweden.

Jan 9, 1913

By John B. Hastings

THE reconnaissance of the Goldfield mining-district, described in this paper, was made in May and June, 1905, and, though this time was too short for a complete report, the work accomplished may serve as a basis for more thorough future research. Dr. Berkey has examined the rocks collected by myself, and I am using his classifications. As a result of further field-work, and Dr. Berkey's examination of the rocks, this paper is an elaboration and correction of my views expressed in the Gold-field Sun, May 12, 1905. The sketch-map, Fig. 1, illustrates the geology of the Goldfield mining-district. Goldfield is an eruptive complex, consisting of alaskite (binary granite), hornblende-andesite, hornblende-dacite, rhyolite, pyroxene-andesite, pyroxene-dacite (sometimes containing, a small quantity of olivine), quartz-felsite, olivine-pyroxene-ande¬site, and basalt. Considering this list to be arranged in the order of eruption, the age-sequence of the rocks conforms to Richthofen's law, formulated in 1868. From his observations in Europe and America, propylite, andesite, trachyte, rhyolite and basalt, occurring together, succeed one another. In a general way, the medium and more acidic rocks precede the most asic-a result supposed by some to have arisen from their relative position beneath the surface, and due to a rude stratification by gravity in the original cooling magma during the older history of the earth, or to the same differentiation occurring during a quiescent (molten ?) period preceding eruption, being aided by the ease with which acidic rocks, mixed with water vapors, become fusible. In effect, the more basic and less re-

Mar 1, 1906

By J. J. Predali, J. M. Cases

J. J. Predali and J. M. Cases (Attachè de Recherche and Charge de Recherche, respectively, Centre de Recherches sur la Valorisation des Minerais, Institut Polytechnique de Nancy, Nancy, France)-The role of CO, in carbonate flotation is one of the parameters of a complex phenomenon: the adsorption of salts of fatty acids onto minerals. The authors therefore must be congratulated for their work. Their experimental results suggest some questions: 1) Recovery with C02, benzoic acid, or HCl, look very similar [(Fig. 1)] to that with the use of air; however, the recovery decreases very slightly (<10%). But in these two kinds of experiments, two parameters are different: the pH which is near 5.8 (with C02) becomes 9.1(without C02) and the concentration of Ca* I x 10-3 mole per 1 (without C02) becomes 1.9 X 10&apos; mole per 1 (without COO. 2) Adsorption experiments (Fig. 2) permit computing the surface coverage 9 which is 7.4% (without C02) and 8% (without CO_.) for an initial concentration of 12 X 10-6 mole per 1 in sodium oleate. It seems doubtful to us that this small variation can produce large increases of the recovery in flotation. 3) It is difficult to correlate adsoption and flotation experiments because they do not seem to have been done with the same size of particles. The concentration needed to obtain 95% recovery (Fig. 1) is about 3.0 X 10_" mole per l, that is, 1.13 X 10-6 mole for about

Jan 1, 1973

By L. E. Shiffman

W. J. Parton—Those operators faced with the problem of treating fine coal whether in bituminous or anthracite will find this paper most timely. I would like to take this opportunity of discussing Mr. Schiffman&apos;s paper and at the same time express certain views relating to our Tamaqua plant. I would like to ask the author what type of impeller and diffuser is used in the Denver cells? Screen analysis of products from individual cells indicate that coarser material resists flotation and only floats after greater retention time in the last few cells. Also, the need for a scavenger screen to reclaim non-floated coal particles further stresses this point. I have always felt that more efficient means of cleaning coal between 10-mesh and 28-mesh existed than flotation. Reagent and power costs are high for the flotation process. When floating +28-mesh particles, cell capacity is lowered and some of the particles are lost with the refuse. The Tamaqua plant of the Lehigh Navigation Coal Co. floats —28-mesh coal and capacity of recoverable coal is 40 tph for 1800 cu ft of Denver cells; or 0.05 tons per cu ft of cell. At Kimberly 7.75 tph for 600 cu ft of cell gives 0.013 ton per cu ft of cell. At Bessie 14 tph for 800 cu ft of cell gives 0.017 tons per cu ft of cell. It would be appreciated if the author would comment on what he feels is the upper size limit of particle to attain most efficient utilization of the flotation process. The dewatering screw is a very interesting development since it offers a simple way to prepare coal sludge for more complete clewatering by drainage or mechanical dewatering on screen or filters. In other words it could be used to accomplish the same thing as a thickener tank. I would appreciate having the author&apos;s comment on how he thinks such a screw dewaterer would work on a froth.* The process as used in floating coal at the Bessie and Kimberly plants may be referred to as more of a bulk oil float in contrast to a froth flotation process. Experiments on increasing capacity of cells is most interesting since we are going through such an experi- mental period at the present time. Recently a double overflow was installed on our No. 30 Denver cells. So far results are not conclusive. In reviewing this paper the following comments are made pertaining to investigation of methods for increasing capacity: Supercharging: Supercharged air in matte flotation or for that matter the use of the normal amount of air drawn in by the impeller would in all probability cause such an aeration in the cell as to destroy the buoyant effect given to the coal particles by the excessive amount of kerosine used. In other words, air creates an agitation zone throughout the cell, creating a boiling and thereby giving a lower recovery in the cell. It would be interesting to know whether the 7 pct increase in recovery was with no air being admitted to the stand pipe. Changing Impeller Speed: The speed of a receded disc impeller for a No. 30 cell as recommended by the Denver Equipment Co. is, I believe, approximately 250 rpm. At this speed and using supercharged air in excess of 8-oz pressure, we have observed a boiling action in the cells. In our flotation we endeavor to obtain some degree of froth flotation using pine oil as a frother. The boiling action as caused by increasing the amount of air added to the cells is detrimental to recovery in froth flotation. It is our belief that to obtain increased recovery from a cell in froth flotation, additional air must be introduced but at the same time this air must be dispersed throughout the pulp in the form of small bubbles and this can only be done by increasing the speed of the impeller. Therefore, if Mr. Schiffman decreased the speed of the No. 30 impellers and at the same time continued to use supercharged air, the boiling action may have been increased because larger bubbles developed. The lower recovery as reported could be due to this factor. Decreasing the impeller speed will definitely decrease the power consumed but may have other disadvantages. First, we believe it will permit "sanding" in the cell and this in our opinion will increase the wear on the impeller and diffuser, especially so, if there is pyrite and/or sand present in the feed. "Sanding" in the cell when air is used, as in froth flotation, will effect the dispersion of this air and cause boiling.

Jan 1, 1951

By L. E. Shiffman

W. J. Parton—Those operators faced with the problem of treating fine coal whether in bituminous or anthracite will find this paper most timely. I would like to take this opportunity of discussing Mr. Schiffman&apos;s paper and at the same time express certain views relating to our Tamaqua plant. I would like to ask the author what type of impeller and diffuser is used in the Denver cells? Screen analysis of products from individual cells indicate that coarser material resists flotation and only floats after greater retention time in the last few cells. Also, the need for a scavenger screen to reclaim non-floated coal particles further stresses this point. I have always felt that more efficient means of cleaning coal between 10-mesh and 28-mesh existed than flotation. Reagent and power costs are high for the flotation process. When floating +28-mesh particles, cell capacity is lowered and some of the particles are lost with the refuse. The Tamaqua plant of the Lehigh Navigation Coal Co. floats —28-mesh coal and capacity of recoverable coal is 40 tph for 1800 cu ft of Denver cells; or 0.05 tons per cu ft of cell. At Kimberly 7.75 tph for 600 cu ft of cell gives 0.013 ton per cu ft of cell. At Bessie 14 tph for 800 cu ft of cell gives 0.017 tons per cu ft of cell. It would be appreciated if the author would comment on what he feels is the upper size limit of particle to attain most efficient utilization of the flotation process. The dewatering screw is a very interesting development since it offers a simple way to prepare coal sludge for more complete clewatering by drainage or mechanical dewatering on screen or filters. In other words it could be used to accomplish the same thing as a thickener tank. I would appreciate having the author&apos;s comment on how he thinks such a screw dewaterer would work on a froth.* The process as used in floating coal at the Bessie and Kimberly plants may be referred to as more of a bulk oil float in contrast to a froth flotation process. Experiments on increasing capacity of cells is most interesting since we are going through such an experi- mental period at the present time. Recently a double overflow was installed on our No. 30 Denver cells. So far results are not conclusive. In reviewing this paper the following comments are made pertaining to investigation of methods for increasing capacity: Supercharging: Supercharged air in matte flotation or for that matter the use of the normal amount of air drawn in by the impeller would in all probability cause such an aeration in the cell as to destroy the buoyant effect given to the coal particles by the excessive amount of kerosine used. In other words, air creates an agitation zone throughout the cell, creating a boiling and thereby giving a lower recovery in the cell. It would be interesting to know whether the 7 pct increase in recovery was with no air being admitted to the stand pipe. Changing Impeller Speed: The speed of a receded disc impeller for a No. 30 cell as recommended by the Denver Equipment Co. is, I believe, approximately 250 rpm. At this speed and using supercharged air in excess of 8-oz pressure, we have observed a boiling action in the cells. In our flotation we endeavor to obtain some degree of froth flotation using pine oil as a frother. The boiling action as caused by increasing the amount of air added to the cells is detrimental to recovery in froth flotation. It is our belief that to obtain increased recovery from a cell in froth flotation, additional air must be introduced but at the same time this air must be dispersed throughout the pulp in the form of small bubbles and this can only be done by increasing the speed of the impeller. Therefore, if Mr. Schiffman decreased the speed of the No. 30 impellers and at the same time continued to use supercharged air, the boiling action may have been increased because larger bubbles developed. The lower recovery as reported could be due to this factor. Decreasing the impeller speed will definitely decrease the power consumed but may have other disadvantages. First, we believe it will permit "sanding" in the cell and this in our opinion will increase the wear on the impeller and diffuser, especially so, if there is pyrite and/or sand present in the feed. "Sanding" in the cell when air is used, as in froth flotation, will effect the dispersion of this air and cause boiling.

Jan 1, 1951

By Jay N. Fairbanks, Richard G. Robinson

This paper discusses a computer program and related formulas for fire fighting responses by coal mine personnel. The computer will interpret the mine air analysis, print reports, and provide relevant graphs allowing quick and accurate responses to coal mine fires.

Jan 1, 1983

By D. Geiselman, A. G. Guy

Single cvystals were grown from high-purity magnesium containing known amounts of nitvogen in the range 0.0008 to 0.0048 wt pet. Crystals of known ovientation were tested in tension in an Instron ma chine to determine the yield strength and to obsevue wheather a yield point occurred. Slowly cooled crystals or those given a solution heat treatment did not show a yield point. However, crystals that were aged following a solution treatment showed a yield point for all of the nitrogen contents studied. It was concluded that nitrogen caused the yield point by the Cottrell mechanism. NITROGEN has been shown to produce sharp yield points in single crystals of cadmium, zinc,2&apos;3 ß-brass,4 and iron,5,6 as well as in polycrystalline iron7 and molybdenum.8,9 Since magnesium has a structure similar to zinc and cadmium, it seemed reasonable that magnesium should also exhibit a sharp yield point provided it contained sufficient nitrogen. Bobalek and Shrader10 reported a total nitrogen content of 0.002 to 0.0065 wt pct in com- mercial magnesium alloys, an amount well in excess of that required by theory. However. magnesium differs from cadmium and zinc in that it forms a stable nitride, Mg3N2, which has a standard free energy of formation of -95,480 cal per mole at 25" c." If rather than being in solid solution, the nitrogen were predominantly combined as the nitride, it could not act to produce a yield point. This type of behavior is the basis for the elimination of strain aging and a yield point in steel by the addition of strong nitride formers such as titanium,12 columbium,13 aluminum,14 vanadium,15 and boron.16,17 Thus, there appeared to be factors both favorable and unfavorable to the production by nitrogen of a sharp yield point in magnesium, and the purpose of this investigation was to determine the actual behavior of magnesium crystals containing known amounts of nitrogen.

Jan 1, 1960

By Dean, R. S.

THE numerous theories of hardening which have been advanced in recent years are all satisfactory in accounting for some of the phenomena observed in hardening metals, but none so far presented account for all of the facts observed. Some years ago one of the authors, R. S. Dean,&apos; presented a theory to account for some of the properties accompanying work hardening. The present paper develops this theory further in the light of recent experimental work and extends it to other forms of hardening. Many of the ideas included have come from the writings and personally communicated thoughts of others. We have attempted to give proper credit in every case, but it is possible that we have not always done so. As an historical basis it is desirable here to review very briefly the hardening theories which have been current. The first comprehensive theory of work-hardening phenomena was due to Sir George Beilby.2 He contributed the idea that with cold work part of the structure of the metal was rendered amorphous and that-it was to this amorphous material that the cold-worked metal owed its difference in properties. According to Beilby&apos;s theory this amorphous material was a supercooled liquid and, therefore, had the characteristics of a vitreous material. That such a theory is not capable of explaining the property changes in metals has been repeatedly pointed out. This theory also allowed a slip to take place only once on a given plane, which, as has been pointed out by Jeffries and Archer13 is not consistent with the observed length of an, individual slip and the amount of elongation which can be obtained by wire drawing. The modifications, which have been proposed to this hypothesis to make it coincide with the experimental facts, have to a considerable extent robbed the theory of its clean-cut characteristics. The commonest of these modifications replaces the amorphous phase with an

Jan 1, 1927

Albin, B. R Billings, Mont. &apos;28 Amster, Nathan L 25 Broad St., New York, N. Y. &apos;28 Bache, Jules S 42 Broadway, New York, N. Y. &apos;28 Barrett, C. P 5338 Harper Ave., Chicago, 111. &apos;28 Bayless, William S Russ Bldg., San Francisco, Cal. &apos;28 Bean, Louis, H 60 E. 42nd St., New York, N. Y. &apos;28 Beatty, Ross J Room 604, 6 N. Clark St., Chicago, III. &apos;28 Benwell, Oswald F Hold Mags. &apos;28 Beymer, Albert S., V.P., Keystone National Bank Pittsburgh, Pa. &apos;28 Blumenthal, Hugo 44 Pine St., New York, N. Y. &apos;28 Boettcher. Charles Ideal Cement Bldg., Denver, Colo. &apos;28 Bowlus, Thomas H., Banker, Pres., Allen County State Bank Iola, Ran. &apos;28 Brown, Colvin B Chamber of Commerce, Washington, D. C. &apos;28 Burt, Maxwell Struthers Southern Pines, N. C. &apos;28

Jan 1, 1934

Albin, B. R Billings, Mont. &apos;28 Amster, Nathan L 25 Broad St., New York, N. Y. &apos;28 Bache, Jules S 42 Broadway, New York, N. Y. &apos;28 Barrett, C. P 5338 Harper Ave., Chicago, 111. &apos;28 Bayless, William S Russ Bldg., San Francisco, Cal. &apos;28 Bean, Louis, H 60 E. 42nd St., New York, N. Y. &apos;28 Beatty, Ross J Room 604, 6 N. Clark St., Chicago, III. &apos;28 Benwell, Oswald F Hold Mags. &apos;28 Beymer, Albert S., V.P., Keystone National Bank Pittsburgh, Pa. &apos;28 Blumenthal, Hugo 44 Pine St., New York, N. Y. &apos;28 Boettcher. Charles Ideal Cement Bldg., Denver, Colo. &apos;28 Bowlus, Thomas H., Banker, Pres., Allen County State Bank Iola, Ran. &apos;28 Brown, Colvin B Chamber of Commerce, Washington, D. C. &apos;28 Burt, Maxwell Struthers Southern Pines, N. C. &apos;28

Jan 1, 1936