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NEW- MEMBERS The following list comprises the names of those persons who became members during the period Feb. 10, 1917 to Mar. 10, 1917. ANDERSON, .LAWRENCE W., Min. Engr., Boston Mine, Utah Copper Co. Bingham, Utah. AUSTIN, JOHN W., Assayer, Magma Copper Co., P. 0. Box 101, Superior, Ariz. BARNARD, C. W., Treas. and Resident Mgr., Arizona Asbestos Assn., Globe, Ariz. BIERMAN, A. C : Geol., Producers Oil Co., Box 75, Houston, Tex. BOCHERT, W. C., Prof. of Mining, South Dakota State School of Mines, Rapid City, So. Dak. BROOKS, FLOYD R., Shift Boss, Mond Nickel Co., Ltd., Worthington, Ont., Can. BROWN, CECIL J., Draftsman &,Surveyor, Wallaroo SC Moonta Min. & Smelt. Co., Wallaroo, South Australia. BURRAGE, ALBERT C., Vice-Pres., Chile Copper Co., 85 Amos Bldg.; Boston, Mass. BURGESS, JOHN ALBERT Genl. Supt., United Eastern Min. Co., Oatman, Ariz. CARLOCK, JOHN BRUCE, Supt., O'Neall Oil Process Co., - 608 Haas Bldg., Los Angeles, Cal. CARPENTER, BYRON H., Min. Engr., . . Willoughby, Ohio.

Jan 4, 1917

Jan 1, 1916

By George J. Young

(Cleveland Meeting, October, 1912.) I. GENERAL. THE recurrence of mine-fires in Nevada during the past decade is not only a matter of interest, but also one of considerable concern to engineers and mine-managers. The more important fires may he enumerated as follows: Forman Shaft fire., Gold Hill, April 21, 1903 ; shaft-house, machinery, and shaft, destroyed; loss estimated at $50,000.; Cause Unknown. Union Shaft fire, Virginia City, July 14, 1904; shaft-house, machinery, and shaft in part destroyed; loss estimated it $100,000; cause of fire stated as the careless throwing of a match in the rope-house. Sutro Tunnel fire, Virginia City, Jan. 27, 1909 ; 700 ft. of tunnel-timbering destroyed, and direct damage of $10,000; cause ' probably electric wires." Belcher Shaft fire, Gold Hill, Aug. 9, 1910; shaft-house destroyed, machinery ruined, and upper part of shaft damaged; damage, $25,000; no cause given. Belmont Mine fire, Tonopah, Feb. 23, 1911; fire started in winze ; 17 men killed. Giroux Mine fire, Kimberly, Aug. 23, 1911 ; fire originated iii shaft-station from unknown cause; 7 men killed, and $34,¬521 damage caused. (NOTE 1.-On June 11, 1912, some time after the present paper was written, a fire broke out in the pump-room on the 2475 station of the Ward shaft, Virginia City. This fire was caused by the short-circuiting and exploding of the starting-switch on No. 5 pump. The oil in the switch was scattered about and set fire to the timbers and laming of the pump-room. The pump-roan in charge notified the surface, and the * Professor of Mining and Metallurgy, Mackay School of Mines.

Oct 1, 1912

By Albert R. Ledoux

I AM indebted to The Kaolin Co. of West Cornwall, Conn., and particularly to its engineer, Mr. M. Wanner, for permission to make public, through the Transactions of the American Institute of Mining Engineers, the interesting results of his experiments, having in view the winning of kaolin from deep deposits without shaft-sinking or removing of the overburden. So far as I am aware, nothing like it has been accomplished heretofore, although it reminds one of the methods successfully employed in Louisiana for the winning of sulphur from deep beds by the sinking of pipes one within another, injecting superheated steam under pressure through one pipe, the heat of the steam liquefying the sulphur and the pressure forcing it up through the other pipe to bins at the surface. The kaolin-deposit at Nest Cornwall is an alteration in situ-that is, it is not sedimentary. A series of clay-veins dipping about 500 from the vertical, lie between a foot-wall of limonite and a hanging-wall of gneiss and hornblende schist. The clay-veins alternate with veins or seams of more or less broken quartz, and unaltered feldspar. The deposit, which occurs at a point about 600 ft. above the Housatonic river, was opened five years ago, and about 5,000 tons of a superior grade of washed kaolin has been extracted from open pits and sold. It soon became evident that this node of extracting the product would prove unremunerative, by reason of the dip of the vein and the intercalary strata and lenses of -quartz, and a more satisfactory method of working the deposit was sought. It is well understood, that, in the preparation of all clays for market, especially residuary kaolin, the most important as well as the most difficult step is the washing of the crude product. The difficulties increase with the percentage of foreign matter, especially quartz and mica, contained in the product, hence a sys-

May 1, 1906

By O. D. Gonzalez

Existing measurements for the steady-state permeation of hydrogen in a iron above 100°C have been examined for contribution of determinate errors. The analysis leads to a recommended equation for the permeability of hydrogen in a iron: o= (2.9 ±0.5) x 10-3 exp - (8400 ± 400)/RT cu cm (ntp H2) cm-1 sec-1 atm-1/2 THE permeability of a iron to hydrogen has been the subject of numerous investigations over the past 40 years, and at present there are thirteen sets of published results for the rate of steady-state permeation of hydrogen in a iron above 100°C. The numerical values in each set of results are entirely self-consis-tent, but the spread among the sets is too large to be attributed solely to experimental error, i.e., to error other than in the specimen itself. Several reasons have been advanced to explain the disparities, but to date the relative importance of experimental inaccuracy to the spread remains uncertain. The purpose of this report is to examine in detail the sources of determinate errors inherent in the experiments and to assess as far as possible the contribution of the errors to the results. The ultimate goal is the selection of values for the permeability and heat of permeation most nearly representative of hydrogen in a iron. The analysis is limited to those experiments in which the permeation rate was observed at steady state—a condition in which traps for hydrogen within the metal are filled to a fixed level15 so that the trapping mechanism is not reflected in the rate of passage of the gas. Furthermore only data are examined in which surface processes are judged to have little or no influence on the flow. It is hoped with these restrictions to obtain values of the permeability and the heat of permeation which will be as closely related as possible to the mechanism of lattice diffusion. I) DEFINITION OF TERMS; UNITS In this report the data for permeation are given in terms of a coefficient oj permeability, ?, which is defined by the equation: jt=?A/?x{p1/2-po1/2) [1] where jt is the total flow of gas normal to the surface of a membrane of planar geometry, e.g., a disc, of area A and thickness ?x; pi and po are the pressures in the input and output sides, respectively. For flow radial to the walls of a membrane of cylindrical geometry, e.g., a tube, the corresponding equation is: where 1 is the length of the cylinder, and ri and ro are the inner and outer radii, respectively. The flux normal to the surface is given by Fick's law: j= -D(dc/dx) [3] At steady state the concentration gradient will be constant, and integration of Eq. [3] gives for the total flow through a disc of area A and thickness Ax: h =-DA(co - ci) [4] where c, and ci are the concentrations of solute at the output and input surfaces, respectively. When surface control is absent, co and ci are given by Sievert's law c = Kp1/2, and substitution therewith into Eq. [4] gives directly Eq. [I] where ? = DK. Integration of Fick's Eq. [3] in cylindrical coordinates will give Eq. [2] where again ? = DK and is thus shown to be independent of geometry (provided that surface control is negligible). The coefficient of permeability, or simply the permeability,* must be expressed in proper units. In *The term permeability will refer in this report always to the coefficient defined above; permeation will be used to specify the general phenomenon of gas passage through a membrane. this report ? will be expressed in the units of cu cm (ntp H2) cm-1 sec-1 atm-1/2. The variations of D and K with temperature are given by D = Do exp(-Ea/RT) and K = KO exp(-?Hs/RT) where E, is the activation energy for diffusion and AH, the heat of solution, each usually expressed in calories per mole of solute. The variation of permeability with temperature will thus be given (for conditions where surface control is negligible) by ? = ?o exp(-?Hp/RT) where ?0 = DoKo and ?Hp = Ea + ?Hs. The units of ?0 are the same as those of 6, and??Hp will be expressed in calories per mole H. 11) SUMMARY OF PERMEABILITY RESULTS Table I gives the values reported to date for the permeability of H2 in a iron in terms of ?o and ?Hp. Except where noted the parameters listed were taken directly from the numbers reported by the various investigators with only a change in units. The temperature limits within which the listed ?o and ?Hp hold are given in column 7; the limits marked in parentheses in this column indicate the entire temperature range covered in each investigation. The listed values of ?o and ?Hp are those giving a linear plot of ln? against T-1 at the higher temperatures in each set of measurements, and thus presumably represent the case for which surface control was negligible. Column 6 gives values of 9 at a representative tem-

Jan 1, 1970

By Sir Robert Hadfield

I am asked to contribute a few words to "The Book of British and American Friendship." This book of the two countries ought never to have been closed. It was a colossal mistake on the part of certain of our statesmen in the past which led to the severing of the interests of the two countries which, by the greatest of all bonds-Nature-were meant to be one. However, that is past, and a new book is opened, one full of promise for the world's future. I should imagine that outside the Kaiser-Junker classes, even the Hun himself would prefer to be under Anglo-Saxon laws and customs rather than his own. At any rate, judging from the number of Huns who have

Jan 8, 1918

By Benjamin F. Merembeck

A mutispectral scanner (MSS) obtains remotely sensed data of the earth's surface in vector form, one vector element for each spectral sensing band of the MSS. Data generated by either airborne or orbiting MSS systems are organized in a lattice of scan lines and elements within scan lines. Each element, called a pixel, is represented by an observational vector and corresponds to a relatively small specific area on the ground. The total observations for a sensed scene frequently are in the millions and are composed of a number of populations, each representing a different land form category. Based on samples from the populations, the mean vectors, or spectral signatures, and the covariance matrices for the categories may be estimated. From these, an among category covariance matrix and a combined within category covariance matrix can be found. The total among category variance is the trace of the among category covariance matrix. Canonical analysis finds a linear transformation matrix such that the first transform variable accounts for the maximum possible part of the total among category variance. Similarly, the second transform variable, orthogonal to the first, accounts for the maximum possible part of the remainder of the total variance, and so on. Such transformation often results in over 95 percent of the total variance accounted for in the first three canonical variables, even though the initial number of spectral bands exceeded twenty. Transformation of bulk data into three canonical variates allows color map products to be developed by assigning each variable to a different basic color. Such color products are believed to be more useful for photo-interpretation than color products resulting from any combinations of three of the initial spectral bands.

Jan 1, 1977

By Albert R. Ledoux

I am indebted to The Kaolin Co. of West Cornwall, Conn., and particularly to its engineer, Mr. M. Wanner, for permission to make public, through the Transactions of the American Institute of Mining Engineers, the interesting results of his experiments, having in view the winning of kaolin from deep deposits without shaft-sinking or removing of the overburden. So far as I am aware, nothing like it has been accomplished heretofore, although it reminds one of the methods successfully employed in Louisiana for the winning of sulphur from deep beds by the sinking of pipes one within another, injecting superheated steam under pressure through one pipe, the heat of the steam liquefying the sulphur and the pressure forcing it up through the other pipe to bins at the surface. The kaolin-deposit at West Cornwall is an alteration in situ— that is, it is not sedimentary. A series of clay-veins, dipping about 50" from the vertical, lie between a foot-wall of' limonite and a hanging-wall of gneiss and hornblende schist. The clay-veins alternate with veins or seams of more or less broken quartz, and unaltered feldspar. The deposit, which occurs at a point about 600 ft. above the Housatonic river, was opened five years ago, and about 5,000 tons of a superior grade of washed kaolin have been extracted from open pits, and sold. It soon became evident that this mode of extracting the product would prove unremunerative, by reason of the dip of the vein and the intercalary strata and lenses of quartz, and a more satisfactory method of working the deposit was sought. It is well understood that, in the preparation of all clays for market, especially residuary kaolin, the most important as well as the most difficult step is the washing of the crude product. The dificulties increaee with the percentage of foreign matter, especially quartz and mica, contained in the product. Hence, a system

Jan 1, 1907

By J. M. Callow

THe results obtained by pneumatic flotation throughout the country on all classes of ore, and the tonnage now being treated by this particular method, speak for themselves. Its advantages over the so-called agitation process are now established by facts and data from practicc. The comparative efficiency of a rapidly revolving paddle, as a means for aerating an ore pulp, and of a cyeloidal or turbine blower for the same purpose, would seem to be so obvious as to leave no room for discussion. Practitioners in this art are to be congratulated on the acquisition of the valuable literary contributions that have recently been made on the theory of flotation by Messrs. Ralston, Van Arsdale, Taggart and Beach, and others, and the very valuable and able articles by Messrs. Laist and Wiggin on "Flotation Concentration at Anaconda, Mont.," by Dr. Rudolf Gahl on the "History of Flotation at Inspiration," and by David Cole on "The Advent of Flotation in the Morenci District." It is not within the province of this article to attempt an answer to the various issues raised in regard to the theory, or to defend the one advanced by me a year ago. But since discussion usually benefits the profession, a reply will be made to some of the statements made by the last-named writers. CoMPABATIVE SENSITIVENESS AND ATTENDANCE Concerning the article, "Flotation Concentration at Anaconda, Mont.," by Laist and Wiggin, a little explanation is in order. It should be stated that, with the exception of about 24 days at the end of the testing period, the Callow experimental plant at Anaconda was not run under my direction. This perhaps accounts for some of the concIusions drawn on page 499 of the descriptive paper. The conclusion that the use of acid seems to be of considerable advantage, calls for some comment. While the tests conducted by the Anaconda Copper Co. do show acid to be of considerable benefit, this is a consequence of using acid sludge as a flotation agent. My belief has always been that the Anaconda

Jan 1, 1917

CARL HENRICH (communication to the Secretary*).-I have read with much interest the discussions of my paper by Messrs. A. S. Dwight, E. P. Mathewson, Win. B. Boggs, Jos. W. Richards, and W. C. Smith. Mr. Dwight's acknowledgment that he always-in lead smelting¬obtained better results by figuring A1203 as an acid in his slags, I may take as a confirmation of my views, notwithstanding his later conversion by, the late T. S. Austin to the latter's empirical view and way of neglecting the consideration of A1203 altogether in the composition of slags-letting the slags "dissolve" in Al203. I have a strong suspicion that Mr. Austin, in a large custom smelting plant at El Paso, has been able to keep the alumina percentage of his slags sufficiently low, not to give him much trouble, although I have also a suspicion that his furnace foreman may have had a somewhat differing opinion of the practical working of the "dissolving" theory,, whenever its applicability was tested to its limits. That Austin should have conceived the notion that the Ca of CaF2 would enter into a slag as CaO, seems hardly in accord with the recognized ability of that late metallurgist. It is a well-recognized fact that even small amounts of CaF2 will reduce the viscosity of a slag; but I did not think anyone ever had an idea that CaF2, in some mysterious way, parted with its F and coupled itself with 0 to satisfy a craving for CaO on the part of 802-least of all in a lead furnace. The "dissolving" theory for CaF2 was doubtless appropriate, and an improvement on figuring the Ca of CaF2 as CaO to satisfy the demand of Si02 for RO bases. However, I cannot understand the rationality of extending this "dissolving" theory to A1203 and to ZnO. It would be interesting to have more specific data from Mr. Mathewson in regard to the actual composition-analyses-of the slags made, when he had these unusually high alumina slags in Colorado. We "old" smelters all know that within certain limits, usually found out by rather tough experience, we could safely "disregard" A1203. In fact, I believe, we never really analyzed for alumina, except in slag analyses, when we

Jan 6, 1917

[Separates of all the Technical Publications published in 1.929 ,are available at Institute headquarters. All the papers are on file in public, university and technical libraries, and when so indicated in the list, maybe found in the TRANSACTIONS.] METAL MINING TECH¬ NICAL PUBLI- TITLE AUTHOR MEETING TRANS. CATION VOLUME No. AND PAGE 182-A-23 The Royal Commission on Mining Henry Louis New York Subsidence Feb., 1929 183-A-24 Cycles in Metal Production D. F. Hewett New York T29t, 65, 93 Feb., 1929 199-A-25 Ventilation ?at the United Verde Oscar A. Glacscr New York T29, 114, 141 Mine Feb., 1929 206-A-26 Air Conditioning in Deep Mines R. W. Waterfill New York T29, 99, 112, Feb., 1929 245-A-27 Bumps in No. 2 Mine, Springhill, Walter Herd New York Nova Scotia (with discussion) Feb., 1929 257-A-28 Misfires: Their Causes, Prevention ? New York and Treatment on Occurrence Feb., 1929 Misfires in Anthracite Coal T. D. Thomas Mines (With Discussion) Misfires in Bituminous Coal W H. Forbes Mines (With Discussion) Misfires in Non-metallic Mining A. W. Worthington (Limestone) (With Discussion)

Jan 1, 1929

By Charles B. Dudley

DEAR SIR: It is now nearly three years since my first report to you on the subject of steel rails was written. That report, as you will remember, dealt principally with the question of the relation between the chemical composition and physical properties of steel rails end their power to resist crushing and fracture in actual service. Other matters were referred to or touched upon in that report, but the main question was, Why do some rails crush or break in service while others do not? Yon will doubtless remember that the principal conclusion arrived at was, that the softer rails are less liable to Crush or break in service than the hard ones. Or, in other words, so far as conclusions could be drawn from the chemical analysis and physical test of 25 samples of steel rails which had actually been in service, these conclusions were that those rails which have the smaller amounts of carbon, phosphorus, silicon, and manganese are less liable to crush or break in service than those which have larger amounts of these elements. Or, again, looked at in the light

Jan 1, 1881

By J. E. Tobey, David R. Mitchell, J. H. Kerrick

DETAILED knowledge of purchase specifications established by coal consumers is essential to the successful design and operation of a coal-preparation plant. ANTHRACITE Specifications should be considered by both the consumer and the producer as guide posts outlining a certain path for both to follow. Plants differ, therefore specifications must differ to meet the varied requirements. Specifications are not of themselves a "cure all" or an assurance of complete satisfaction in fuel utilization. Specifications should not be regarded as a license to engage in an orgy of buying any and all coals that may happen to fall within their limits. This would lead to the indiscriminate mixing of coals which may vary in their burning characteristics. Different coals of equal grade tend to be individualistic in their burning characteristics. Rather, specifications should be used to help simplify coal selection, to reduce the actual number of coals used over a given period; in other words, to have a stabilizing influence on coal or customer turnover. In the final analysis, the use of too many coals per year in a plant is costly to both the consumer and the producer. Too many sources usually result in higher operating and maintenance costs for the consumer and higher sales costs for the producer. Finally, the statement included in the report accompanying the com¬prehensive Coal Selection Charts prepared by the Coal Committee of the National Association of Purchasing Agents, and released in 1938, is significant. This Committee worked diligently for a period of 15 years seeking to find a scientific and reliable method for selecting coals. The two following paragraphs are quoted from its report: More important is the fact that no ready-made classification or set of specifications can possibly replace the judgment and resourcefulness of an experienced combustion engineer or fuel technologist, nor the usual need for full scale plant tests under the exact conditions of use before a final decision is made ...

Jan 1, 1943

By A. C. Rubel

WHAT does management expect of W and from an engineer? First and foremost, it expects that he should become, and therefore should fit himself in every way to be, a part of management so that he may assume as much and as many of the responsibilities of management as his ability and the opportunities of the job permit. Let me make clear at the start that the profession of pure, technical engineering offers but limited opportunities at the top levels because of the inherent organization of engineering work. The line of succession to top jobs may be likened to a cone with a broad base and an extremely sharp point. Consider any oil company, large or small, or any operating function of that company, and you will find few top engineering jobs in the organization. This is true by the nature of the work handled. There will be a few district engineers depending on the spread of operations, a chief petroleum and production engineer, perhaps a few research engineers, possibly some technical executive assistants, and that is usually all. The road to these jobs is a long one and the competition is tough. The larger the organization the greater the opportunity, but always the ratio of engineers to top engineering jobs is only a small one.

Jan 1, 1947

By C. R. Van Hise

[Concluding Contribution of Prof. Van Hise to the Discussion of his Paper, and Others on the Same General Subject, presented at the Washington Meeting, February, 1900 (see Trans., xxx., 27, 177, 323, 424, 5 S); also of the contributions of Vogt, De Launay, Beck, Lindgren, hemp, Rickard, Bain, Keyes, Collins and Adams, presented at the Richmond Meeting, February, 1901, and printed in the present volume.] IN June, 1900, shortly after my paper was published in the Transactions, I made a briefer statement* before the Western Society of Engineers covering the same `round, which, in certain respects, is somewhat of an improvement. For instance, instead of using the terms descending and ascending with reference to the waters resulting in the two concentrations, my modified statement is as follows " The first concentration of many ore-deposits is the work of a relatively deep water-circulation, while the reconcentration is the result of reactions upon an earlier concentration through the agency of a relatively shallow water-circulation. Commonly the deep water circulation is lacking in free oxygen, and contains reducing agents, and the shallow water contains free oxygen. The deep water is therefore a reducing, and the shallow water an oxidizing agent."† Of the papers upon ore-deposits which, in vol. xxx. of the Transactions, follow my own, or which were presented at the Richmond meeting, a considerable number are wholly confirmatory of the conclusions which I have presented. Among these are the Washington paper of Emmons upon the Secondary Enrichment of Ore-Deposits‡ and his discussion at Richmond of other papers,§ that of Weed upon the Enrichment of Gold and Silver Veins,[ ]the discussion of Emmons', and at Richmond of Weed's paper by Collinst and Prof. De Launay,† the paper of Lindgren on Metasomatic Processes in Fissure Veins,¶ that of-Rickard upon the Formation of Bonanzas in the Upper Portions of Gold Veins,** and the remarks of Bain upon the Mississippi Valley lead- and zinc-deposits.†† It is therefore un-

Jan 1, 1902

By Walter Herd

FoR the past eight years No. 2 mine of the Cumberland Railway & Coal CO., Springhill, Nova Scotia—a subsidiary of the Dominion Coal Co., Ltd.—has had an unenviable reputation for bumps. As the workings extended in certain directions under a greater cover, these bumps increased in severity and it became apparent that some change in the system of extraction was necessary if the mine was to continue to operate. In September, 1924, following several fatalities resulting from bumps, the Mines Department of Nova Scotia requested from the U. S. Bureau of Mines the services of George S. Rice, Chief Mining Engineer of the Bureau, to report on the conditions then prevalent in No. 2 mine, Springhill. This request was promptly and courteously granted. Mr. Rice made a full investigation and a comprehensive and helpful report, which is embodied in the 1924 Annual Report of the Department of Public Works and Mines, Nova Scotia. Prior to 1925, the room and pillar method was employed and in January of that year (there being a cessation of work from March to August due to labor troubles) longwall retreating on the west side, on a limited scale, and in a small section on the east side of the mine was started. The major portion of the east side was not operated on this system till August, 1926, as there was developed a considerable area ready for pillar extraction between an arbitrary boundary and a point up to which bumps of any consequence had not been experienced. In the interval development work for longwall retreating below the 5900-ft. level was vigorously pushed. This longwall retreating system was suggested by Mr. Rice as a possible remedy and was heartily endorsed by the company officials. This paper describes the conditions and happenings subsequent to Mr. Rice's report and more especially the results with the longwall retreating system of mining under the peculiar circumstances pertaining to mining No. 2 Seam, Springhill, at depth, and records the conclusions which experience with several severe bumps under this mode of extraction would suggest. Except where necessary to make the paper intelligible as an entity any duplication of Mr. Rice's report will be avoided.

Jan 1, 1930

By F. C. Stanford

The work of an engineer is to direct natural forces so that the: bring about the results that he wishes to secure. Heretofore he ha concerned himself chiefly with physical forces and inanimate objects until he has secured a truly marvelous degree of control over them The great problem of the present age is to secure a like degree of know1 edge and control of the human factor. Progress has already been made along this line, but it is only a beginning. Wilhelm Ostwald says tha scientific knowledge enables a man to be a true prophet; but it must be remembered that a good many people do not seem to be able to main tain a high average in prophecy. In short, 'the average of knowledge is not equal to the average needs of the present time, but continually fails to keep pace with it. It has been aptly said that the really essentia need of the period is for more brains; if we only had sufficient knowledg and sagacity we could not only solve all difficulties, but prevent then from arising. This generalization holds good for an industrial organization. Th most vital need of the management is for more brains. The logica course for an engineer in charge of an industrial organization is, therefore to direct whatever forces may be at his command toward the development training, and guiding of all the brains in his organization. This is easie said than done, for it involves the carrying on toward two objective: the maximum of productive work, and the development of the individual who perform it. This is essentially like the rebuilding and enlarging of plant, keeping it in full operation the while. On the other hand, if th aim is merely for maximum production from an organization, withou offering opportunity for development, the final outcome will necessari be like that of a plant that is driven at full capacity without stoppin for repairs or improvements; it eventually becomes so run down th either a complete rebuilding is necessary or else it has to be abandone

Jan 1, 1918

By Frederick Prime

AT the last meeting of the Institute, Mr. A. L. Holley read a paper on "Steel," in which he proposes for it a definition so opposed to the one generally received, as to call for some remarks. Until within the last five or six years there has been no dispute on the subject, and it seems worth while to investigate the matter. For not only does a proper tax on all importations depend on a proper appreciation of the term steel, but it is necessary to know whether steel, or wrought-iron, or homogeneous iron are requisite in all processes of manufacture in which malleable iron is employed, on account of cost, strength, etc. Karsteu* says : " Iron may be obtained, either as an unforgeable, unweldable metal, which melts at a high heat, termed cast-iron; or as a ductile, weldable, soft metal, which can only be melted at the * Karsten, Handbuch der Eisenhüttenkunde, 3d ed., vol. i, p. 6. Berlin, 1841.

Jan 1, 1876

By M. L. Fuller

DURING the last several years many papers have appeared dealing with the structure of highly polished metal surfaces. The awakening of interest in this subject is due to the applicability of the electron diffrac-tion technique to the study of surfaces. The original theory of Beilby1 considered the surface of polished metals as of the nature of a super-cooled liquid or a vitreous, amorphous solid. The electron diffraction effects from polished metals have been interpreted by many to be a direct experimental proof of the correctness of the Beilby theory. This inter-pretation has been strongly opposed by others, so that at the present time the subject is in an uncertain and controversial state. In the present paper new, and hitherto unpublished, electron diffrac-tion effects from polished zinc are described. These observations indicate that the polished surface of zinc is crystalline.

Jan 1, 1938

By B. E. Eakin, A. L. Lee, M. H. Gonzalez

Expeximental viscosity and density data of lour natural gases are presented for temperatures from WO to 340F and pressures from 100 to 8.000 psia. A correlation is also discussed and results reported. INTRODUCTION This investigation is one of several efforts by the authors to provide viscosity data for pure hydrocarbons and mixtures. Results of some pure hydrocarbons and their mix tures have been presented." Several predictive methods and correlations have also been reported.'," This paper presents the experimental viscosity and density data of four natural gases and confirms a correlation in a previous study. APPARATUS The viscometer was described previously. 2,6 A bank of stainless steel pycnometers was included to determine density in conjunction with the viscosity measurements (Fig. I). DATA AND MATERIALS The natural gases were furnished by the Atlantic Richfield Co. (Samples 1 and 21, the Continental Oil Co. (Sample 3) and the Pan American Petroleum Corp. (Sample 4). Table 1 shows the composition of these gases obtained by mass spectrometer analysis. The pure component viscosity data used in the correlation have been published."".'"', '" Experimental and calculated viscosity data for the natural gases are presented in Tables 2 through 5. CORRELATION Starling and Ellington"' have reported several semi-empirical expressions based to a certain extent on the theory of viscosity advanced by Born and Green.' The final expression presented by Starling and Ellingto'n is: i'. (micropoise) -- /t,, exp rX(7') p ..... (I) Eq. 1 was modified by Lee et 01." to represent mixture and pure component data simultaneously. This equation has the form: F = K exp [XpY] :.........(2) where K=- (7.77 i 0.0063M)Ti 122.4 + 12.9M +T .................(3) ' ' ' X= 2.57 + ---1914.5+ 0.0095M .... (4) Y = 1.11 -r 0.04 X ........(5) Over the pressure and temperature range studied in this investigation, this equation represents the data on methane, ethane, propane, n-butane and four methane-n-butane mixtures with a standard deviation* of ? 1.89 per cent. Density data by Sage and Lacey" were used to fit the equations. Eq. 2 gives reliable values of the viscosity of light hydrocarbons without prior knowledge of experimental viscosity values, but accurate density data must be available. Eq. 2 was used to predict viscosity values for the natural gases studied in this paper. The particular set of parameters contained in Eqs. 3 through 5 gave values that reproduced experimental data within 25 per cent. Needless to say, in using Eq. 2 better density values will give better viscosity results. However, those engineers who do not have accurate density values at hand or the time, or such facilities as a library, computer, etc. readily available, may feel uneasy in using Eq. 2. Therefore, the authors sought the easiest but by no means best density prediction method, which was reported by Kaf 30 years ago. A set of density values, which were calculated based on Kay's method, and a generalized compressibility factor chart were used to fit Eq. 2. The results are:

Jan 1, 1967