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The following is an incomplete list of members and guests who called at Institute headquarters during the period Jan. 10, 1918 to Feb. 10, 1918: K. Baumgarten, San Diego, Cal. J. A. Meyerovitch, Petrograd, Russia. F. J. Brine, Toronto, Ont., Canada. C. Naramore, Washington, D. C. W. A. Castleton, Salt Lake City, Utah. Orrin P. Peterson, Wausau, Wis. J. Ross Corbin, Boyerton, Pa. William H. Rea, Pittsburgh, Pa. W. M. Corse, Buffalo, N. Y. W. Murray Sanders, Tucson, Ariz. W. A. Deane, Summitville, N. Y. Edmund F. Saxton, Philadelphia, Pa. S. E. Doak, Philadelphia, Pa. William C. Schmidt, Humboldt, Ariz. F. G. Downs, Jersey City, N. J. G. J. Sielaff, Oakland, Cal. Albert H. Fay, Washington, D. C. A. D. Sproat, Bound Brook, N. J. F. Julius Fohs, Tulsa, Okla. J. A. Stader, Joplin, Mo. A. L. Gholz, Minneapolis, Minn. A. K. Stewart, Mine La Motte, Mo. Ruger W. Hay, Easton, Pa. Geo. W. Tower, Jr., New Rochelle, N. Y. Stanley C. Herold, Pittsburgh, Pa. Henry Traphagen, Toledo, Ohio. A. A. Holland, Montreal, Canada. H. E. Treichler, Chuquicamata, Chile. T. Z. Humphrey, Anaconda, Mont. Paul M. Tyler, Fairlee, Vt. H. M. LaFollette, LaFollette, Tenn. F. R. Van Campen; Seattle, Wash. J. B. Lain, Goldfield, Nev. Thor Warner, Phoenix, Ariz. J. R. Lashbrooke, Los Angeles, Cal. Clarence Woods, Narrows, Va. W. F. Lewis, Ewen, Mich. E. N. Zern, Pittsburgh, Pa. C. E. McQuigg, New Haven, Conn. Robert J. Anderson has resigned his position as chief chemist and metallurgist of the Cleveland Metal Products Co., Cleveland, Ohio.

Jan 3, 1918

By A. J. McEvily, R. C. Boettner, C. Laird

The processes leading to fatigue failure in the low-cycle range were studied to obtain an understanding of the basis of Coffin's law. Particular attention was paid to the manner of mack nucleation and to the determination of the portion of the total lifetime spent in crack propagation. It was observed that cracks are nucleated at surface notches meated during reversed plastic deformation, Principally at grain boundaries, and that crack growth occupies greater than 75 pct of the fatigue life. When inclusions are present, they are often the primary sites of crack initiation. From consideration of the incremental distances advanced by a crack in each cycle and of the lifetimes of different materials, it appears that the universality of Coffin's law arises from the similarity of crack-tip strain for a given applied strain amplitude, irrespecti7:e of material. STUDIES of low-cycle fatigue have been particularly rewarding in that a simple correlation between fatigue lifetime and plastic-strain range has been shown to exist. This empirical relationship takes the forml,2 Nner=C [1] where N is the number of cycles to failure, Er is the plastic-strain range defined as the total plastic strain per cycle (the sum of the tensile plastic strain plus the compressive plastic strain), n, the exponent, is a constant independent of the material to a first-order approximation and often has a value of about 0.5, and C is a constant which for a number of ductile and metallurgically stable materials is approximately 0.65 for fully reversed strain.3 This relationship has been shown to be valid for a wide variety of metals and alloys and is often referred to as Coffin's law. However, it is yet not clear why so many different metals and alloys exhibit the same over-all behavior in the low-cycle range. Less is known about the mechanisms of fatigue failure in the low-cycle range than in the high-cycle range, but it is expected that the processes would have much in common. For example, an important characteristic common to both high-and low-cycle ranges is that fatigue crack propagation can occupy a considerable portion of the total lifetime. This has been shown by Laird and smith4 by a count of the number of ripples present on the fracture surface of copper specimens, each ripple corresponding to one cycle of load. On the other hand, some marked differences have been noted. For example, in copper,5 nickel, and aluminum4 there is a greater tendency for grain boundary cracking to occur as the strain amplitude is increased. The purpose of the present work was to study further the processes leading to fatigue failure in the low-cycle range and to obtain an understanding of the basis for the validity of Coffin's law. Particular attention has been paid to the manner of crack initiation and to the determination of the portion of total lifetime spent in crack propagation. MATERIALS A number of metals and alloys were tested, although more attention was focused on a particular few, once general trends had become apparent. Alloys were selected so as to investigate the effects of crystal structure, number of phases, stacking-fault energy, and impurity content. The materials in this grouping were: high-purity copper OFHC copper 1100 aluminum (commercially pure) 70-30 brass (Cu-30 wt pct Zn)

Jan 1, 1965

By W. L. Kerlie, J. H. Richards

The variation in hydrogen content of basic open-hearth steels during refining and the effect of changing from steam to air atomization were studied. The water content of the furnace atmosphere, the slag basicity, and the degree of oxidation of the slag-metal system largely control the hydrogen in the steel. SMALL amounts of hydrogen have an adverse effect on the ductility of steel and a wide range of hydrogen contents has an adverse effect on the internal soundness of both ferrous and nonferrous castings. This has been of major concern to the metal industry, both manufacturers and fabricators, for many years. As one of the results of continuing investigations of the hydrogen problem, much has been learned about methods of reducing the hydrogen content of liquid metals below the relatively high levels that are normally associated with such phenomena as rising ingots and excessive porosity in sand casting. However, it was not until a reliable and simple method for sampling and analyzing liquid metal was developed that much progress was possible in quantitatively evaluating the effect of steelmaking practice on hydrogen contents at levels below 6 to 8 ppm. Throughout all the work described in the following presentation the Geffner pintube technique was used to obtain samples of liquid metal1 * and the tin-fusion method, developed at Massachusetts Institute of Technology,2 was used to analyze the samples. Before attempting a systematic experimental program for minimizing the hydrogen content of open-hearth steels, it was necessary to determine the variation in hydrogen in the open-hearth bath during the normal processing of a heat. The logs of ten heats are illustrated in Figs. 1 through 7. The number at each point on the graphs refers to the number of pintube samples analyzed for hydrogen. An increase in the hydrogen content of the liquid metal during the early period of refining is apparent in all heats. There is evidence of a decrease in hydrogen later in the refining period, see Fig. 2, for example. Therefore, the existence of a maximum hydrogen content at some intermediate time during the refining period is anticipated. To test for the existence of a maximum, the data illustrated in Figs. 1 to 5 were grouped together so that they could be examined on a collectively comparable basis. The grouping was effected, as illustrated in Fig. 8, by superimposing Figs. 1 to 5 so that the apparent hydrogen maxima coincided at a fixed position, indicated by the zero on the time axis. Also, by vertical adjustment until the graphs appeared to the eye to be superimposed, the hydrogen scale was made to show the change in hydrogen content. That is, a standard amount was subtracted from the hydrogen values for each heat. Therefore, Fig. 8 represents a generalized presentation of the data and, for this reason, cannot be used to predict the actual hydrogen content of the bath during refining, but rather to show the probable rate of change in hydrogen during refining. Statistical examination of the grouped data in Fi.g. 8 shows that the apparent. increase and suhsequent decrease in hydrogen are real and confirms the existence of a maximum in general. The average increase In hydrogen during the early period of refining is between 0.8 and 1.3 ppm per hr, and the

Jan 1, 1958

By George H. K. Schenck, Peter G. Donald

There is an accelerating acceptance of change by management of cement companies. Diversity of response is noticeable in efforts across the country to reverse the downward trend in profits that brought margins in 1966 to the lowest point in 20 years. New concepts are emerging among managers as they seek to increase the efficiency in use of the basic corporate resources of men, capital and technology. The shift towards computerized control of cement manufacturing is making new gains as is diversification of cement companies into allied fields such as production and sale of natural and light- weight aggregates, crushed stone and concrete products. Increased interest in special products such as white cement and further moves overseas are also significant. Perhaps the most dramatic event of recent years occurred in Washington at hearings before the Federal Trade Commission where cement producers split on whether there should be FTC guidelines that would prevent ownership of ready-mixed concrete producers by cement companies.

Jan 4, 1967

By James E. York

AT a meeting of the American Society for Testing Materials at Atlantic City, June, 1908, Dr.. C. B. Dudley, in his presidential address,' showed the vital necessity of not only making a steel rail as good as in the past, but of making it considerably better in order to meet the present and prospective require¬ments of railroads. Doctor Dudley requested the co-operation of all who from personal experience could give information that would result in bringing about the production of a steel rail that could be relied upon to meet the present requirements. I have had considerable experience in the practical manufacture of steel of almost every grade, during the past 40 years, and I shall suggest changes that will bring about the results desired. Doctor Dudley has had a long experience as chemical and metallurgical expert for the Pennsylvania railroad, but he frankly admits that up to the present time both he and other metallurgical experts lack the practical knowledge of steel-making that is necessary to state correctly the reasons for the unreliability of the steel rails now produced. The necessity is self-evident for more positive practical knowledge on the part of these experts of what is possible and what is impossible regarding the practical manufacturing of steel rails from the ingot to the, finished product. Chemical knowledge in steel-making is far in advance of what it was years ago, and might be said to cover every requirement (in that department) for producing reliable steel. The study of the metallography of steel has been of great value, also the physical testing of steel, but this knowledge will only de-

May 1, 1909

By FRANK R. VAN

I. INTRODUCTION. IN the summer of 1908, R. B. Cochran, Superintendent of the Compania Metalurgica Mexicana at Sierra Mojada, Mexico, presented to the Department of Geology and Mineralogy at Case School of Applied Science an interesting series of silver-, copper-, and lead-ores from the Veta Rica mine. These ores contained several interesting minerals which were associated in a somewhat peculiar manner, so that I was impelled to make a closer study of their occurrence. The investigation has brought out several new facts concerning the geology of the district and the geological occurrence of the ores, and therefore has seemed worthy of record. Two papers have been published previously about the region, one by Chism1 in 1887, and the other by Malcolmson2 in 1902. These articles, however, treat of the district more from the stand-point of the metallurgist and mining engineer, and not much attention is devoted to its mineralogy and economic geology. II. GEOGRAPHICAL LOCATION OF THE DISTRICT. The Sierra Mojada is situated in the extreme western part of the State of Coahuila, near the Chihuahua boundary. It is reached best via the Mexican Central railroad from El Paso, Tex., to Escalon, Chihuahua, a distance of 494 miles. From this point, a branch line, the Mexican Northern railroad, runs 78 miles in a NE. direction to the mines, which are its northern terminus. The railroad was built about 1890, practically on account of the Sierra Mojada mining-district. 1 Sierra Mojada, Mexico, by Richard E. Chism, Trans., xv., 542 (1886-87). 2 The Sierra Mojada, Coahuila, Mexico, and Its Ore-Deposits, by James W. Malcomson, Tram., xxxii., 100 (1901).

Aug 1, 1912

By Albert Sauveur

My first paper dealing with the theories of the hardening of steel by rapid cooling was published in the Transactions of this Institute in 1896— 30 years ago-under the title "The Microstructure of Steel and the Current Theories of Hardening," hence, also, the title of the present paper. It was extensively discussed and was, I believe, one of the starting points of many subsequent papers and discussions of the same subject, dis-cusssions which at times became almost violent and which led to the formation of different schools such as the "Carbonists" and the "Allo-tropists." Some of the older members of the Institute, who took part in the debate or who were interested observers, will, I am sure, have kept a vivid remembrance of it. The controversy gradually quieted down, apparently for lack of ammunition, without any side acknowledging defeat. Recently, however, interest in it ha been revived through the claims of some that these vexed questions had at last been solved. In an effort to ascertain if possible the prevailing view of those best qualified to express an opinion a questionnaire was submitted to the following gentlemen: J. 0. Arnold Sir Robert Hadfield Edgar C. Bain W. H. Hatfield Carl Benedicks Samuel L. Hoyt N. Belaiew Kotaro Honda H. M. Boylston Zay Jeffries Harry Brearley H. Le Chatelier G. K. Burgess H. H. Lester William Campbell Francis F. Lucas H. C. H. Carpenter John A. Mathews Pierre Chevenard A. McCance P. Dejean Albert Portevin C. A. Edwards Walter Rosenhain F. Giolliti Bradley Stoughton G. Grenet F. C. Thompson Leon Guillet

Jan 1, 1926

By Thomas Haight Leggett

I.—The Deep-Level Shafts. The gold-deposits of the Witwatersrand (Anglice, " White Waters' Range ") are, as is well-known, more or less parallel and tilted sedimentary beds of quartz-pebble conglomerate impregnated with gold. These beds, however, are locally called "reefs"—a term equivalent in signification to the American "ledge"—and, like the latter, usually applied to lodes, though covering in practical usage all deposits of tabular form. The first developments of the reefs of the Rand were naturally made along their outcrops. Since the mining law of the Transvaal does not confer upon locators the "extralateral right," the property of each locator upon the outcrop or apex ends with the vertical planes drawn through the boundaries of the claim. Consequently those portions of the reefs which lie "on the dip," beyond these boundaries, are separately acquired by locating new surface-claims, and are usually to be mined only by means of vertical shafts, reaching the reefs at considerable depths. The term "deep-level properties " is given to such claims on the dip, and the " deep-level shafts " are the vertical shafts sunk in the hanging-wall of the Witwatersrand reefs, in contradistinction to the incline-shafts almost universally employed on the outcrop-properties. Number and Distribution.—The accompanying diagram, Plate I., shows the number and depth of these deeplevel shafts, completed or under process of sinking, up to January 1, 1900. A number of shafts already located upon new deep-level properties, but upon which no work has yet been done, are not included in this diagram.* Vertical shafts sunk upon outcrop-

Jan 1, 1901

By L. H. JEFFRIES

In the mining operations of The Canyon Corp., Deadwood. S. D., the use of mucking machines has been of definite advantage. The type used is that which depends upon the traction of the motor-driven wheels to crowd the dipper into the muck pile, while the car in which the muck is received is coupled to the mucker and moves forward or back with it. This general arrangement is entirely satisfactory on a substantially level track. The ores which occur in this district are a replacement of dolomite and the beds are now tilted to an inclination of about 7-1/20. In our operations it is necessary to drive inclines down-hill on this slope, which makes a difficult hand-mucking job even if water were not present. With these facts in mind, an attempt was made to use the mucking machine for driving down the in- cline, but as expected, the traction was insufficient to handle the machine and the necessary car. The means used to correct this condition will perhaps impress most readers as too complicated and cumbersome to effect any economy, but the idea may be of service to some who have a similar condition. After considering several s

Jan 1, 1940

By Joseph W. Roe

MANY questions arising in the work of the mining engineer may be solved quickly and with sufficient accuracy by the methods of descriptive geometry; but, unfortunately, this subject is more often considered from a mathematical view-point than as an effective tool. for solving practical problems. Some of the principles involved are merged into the ordinary operations of mechanical drawing, and are used unconsciously by the engineer in his every-day work. The rest are stowed away on the book-shelf with his forgotten or rarely-used college text-books. One reason for this condition of "innocuous desuetude " may lie in the unfortunate and often cumbersome notation which it has been found necessary to introduce. If some of these principles can be recalled to the engineer's attention in terms of every-day use they may prove of practical bearing. Recently, in talking with several mining engineers, I used some of the drawing-room methods of a machine-designer, to the evident surprise of those around me. These men were perfectly familiar with the methods, but their application to mining-work had not occurred to them. At their suggestion the present paper is offered, not in any way as a treatise, but merely to suggest a certain point of view, in hope that it may lead others far more familiar with mining-problems to pursue the subject further. I. To FIND THE STRIKE. As the simplest and most fundamental problem, let it be required to find the strike of a vein when the location and elevation of three points on the outcrop are known. It will be assumed for the present that the vein is a plane.

Mar 1, 1910

By Walter P. Jenny

I. The Reducing Action of Carbon and of Hydrocarbons,. .. 445 11. Protective Action of Carbon and of Hydrocarbons,. 451 111. Contributory Action of Carbonic Acid Gas,..452 IV. The Stability of Carbonic Acid and of Water,..453 V. Occurrence of Carbon and the Carbon-Compounds,. 455 VI. The Occurrence of Carbon, Alone,.... VII. The Occurrence of Carbon Combined with Hydrogen,. .. 460 VIII. The Relative Reducing Power of Minerals,..487 I. The Reducing Action of Carbon and of Hydrocarbons. Carbon has long been recognized as one of the most powerful reducing agents in the deposition of ores. Investigations, made by myself, of the zinc- and lead-deposits in Southwest Missouri, in the region centering about Joplin, where the formation of the metallic sulphides has been due to the action of bitumen, carbonaceous shales and bituminous coal, have afforded abundant evidence that the solid oxygenated hydrocarbons, particularly when in fine powder and in suspension in the waters circulating through the ore-bodies, are the most energetic and powerful reducing agents known. Bitumen, liberated by the decomposition of the ore-bearing limestone, is found in the Joplin mines in all degrees of fluidity and hardness, dependent on the amount of oxidation it has undergone. From semi-fluid maltha it grades into partly oxidized mineral-pitch, which, by further oxidation, changes to hard asphalt, finally breaking up, from continued absorption of oxygen, into a fine powder resembling in appearance powdered coal. In this condition oxidized bitumen, from its light gravity, is transported readily in suspension in the underground circulating-waters. Bituminous coal and black carbonaceous clays and shales occur as surface formations, often in intimate association with

Jan 1, 1903

By B. Silliman

The regions of New Mexico referred to are in Socorro, Grant, and Dona Ana counties, and a portion of Lincoln County, embracing in the aggregate a very large area, of most of which our knowledge is as yet very fragmentary and superficial. It is only very recently that large portions of this region have been accessible. It has been full of danger from hostile bands of wandering Apaches, whose murderous raids have slain many adventurous miners and seriously prevented developments. But this evil has now been largely abated, and in many of the mining camp of this region there is no longer any danger from this cause. SOCORRO MINES. About three and a half miles back of the old Mexican town of Socorro, on the Rio Grande, chief town of the County of Socorro, are two or more large veins of heavy spar, cutting across the fat* of Socorro Mountain in a northeast and southwest direction, and dip ping at an angle of about forty degrees into the body of the mountain. These veins are in rhyolite, and, so far as could be seen in openings on the Torrence Mine, which I examined, are without any clay parting or selvage. The average thickness of the Torrence rein may be about five feet, the thickness varying from pne or two feet to thirteen feet. Upon the cleavage planes of the heavy spar occurs, in visible patches, of a waxy Iustre and gray color, silver chloride, which gives value to the vein, from a few ounces up to one hundred and twenty ounces to the ton, averaging about forty ounces, as I

Jan 1, 1882

By Frederic P. Dewey

At the Seventh International Congress of Applied Chemistry I presented a paper,' The Assay and Valuation of Gold-Bullion, in which are briefly mentioned a few illustrations of different methods of sampling gold-bullion, particularly cyanide-bars. Since then I have carried on an extensive investigation upon the sampling of gold-bullion in relation to its effects upon the assay-results, in connection with the statement of accounts between the smaller assay-offices of the United States which purchase gold-bullion and the mints where the purchases are re-deposited. Under the name of gold-bullion are included metals of widely different composition. We may have practically pure metal, 999.75 fine or even more in gold; alloys of .gold and silver with only trifling amounts of base metal; alloys of gold and copper with trifling amounts of other metals; ternary alloys of gold, silver, and copper, or gold, silver, and lead; and most complex alloys of from five to eight or more constituents of ordinary occurrence, besides some of the rarer metals occasi'onally. In any one or all of these classes we may have one or more of the metalloids, which may add to our difficulties. Of course, with metal 999.75 fine in gold there is only slight opportunity for different samples to differ in fineness, but on such fine metal we expect the assays to agree very closely, and the sampling must be done with the utmost care. When possible, dip- or granulation-samples of the molten metal should be taken; but when it is necessary to sample bars, the chief point to guard against is surface-dirt.

Jan 1, 1913

By Michael A. Devane, Neil Duncan

Inclines and tunnels can extend from ground surface to considerable depths traversing a wide range of lithologies. The strata encountered may be affected by loosening and induced stresses at different locations along the route. It is suggested that Phase I of the pre- driving assessment process should include study of the geology, hydrogeology, rock material and rock mass characteristics. A rock mass disruption factor is used to express the ratio of the unconfined strength of intact rock material to the unconfined strength of in situ rock mass. It is suggested that there is a relationship between in situ (secondary) permeability values and the disruption factor, since the permeability of the rock mass is governed by parameters which influence strength. In Phase I1 of the pre-driving assessment, consideration should be given to the prediction of primary loosening which results largely from disturbances to the rock mass arising from the driving process. Also in Phase 11, preliminary assessments are made of the effects of induced stresses and of the geodurability characteristics of the rocks. In Phase 111, the mechanics of various secondary loosening pro- cesses are considered along with their relevance to estimates of stand up time and support requirements. Yield-line analysis is introduced for the study of plastic and brittle type bending deformations. Stand up time and support characteristics are also assessed. In Phase IV, the effects of induced stresses are analysed. It is suggested that even for broken rock in the Yield Zone, the rock mass disruption factor may not often increase above lo which is equivalent to an in situ permeability of 10-1 m/s.

Jan 1, 1983

By C. O. Burgess, A. B. Kinzel

Although vanadium is an important constituent of almost every brand of high-speed steel manufactured today, little is known as to its role in this series of alloys. The now standard 18 per cent tungsten and 4 per cent chromium constituents were the result of developments and improvements before 1903. In that year, vanadium was added to the steel by Dr. J. A. Mathews. This proved to be an outstanding contribution, so that the standard high-speed steel of today is generally referred to as the 18-4-1 type—18 per cent W, 4 per cent Cr and 1 per cent V. Various modifications have been attempted since then, but with the exception of the introduction of cobalt, no striking improvements have occurred. Vanadium has been increased to 2 per cent in many of the common brands, and at least one brand contains 5 per cent V in addition to the usual tungsten and chromium. The carbon has been gradually increased so that it is not uncommon to find 0.80 per cent in the standard grade, although the carbon in the 5 per cent vanadium steel mentioned above is approximately 1 per cent, and even 1.2 per cent has been made experimentally. The role of vanadium has never been well understood, and although vanadium has been increased to 2.5 and even 5 per cent in certain high speed steels, it has not been generally established that the higher vanadium contents result in superior cutting properties. However, in all of the investigations, of which the writers are aware, the interrelation of the vanadium and carbon contents was not considered as a prime factor. The carbon content was held at 1.2 per cent or less—generally at the usual 0.65 to 0.75 per cent. Theoretical Aspects Although the role of vanadium is not understood, there are theoretical considerations which indicate definite reasons for the improved cutting effciency due to vanadium. Refinement of the secondary grain is one distinct possibility. The well-known action of vanadium in limiting grain size might well be expected to operate in high-speed steels, and even though its action were not evident in the parent austenite grain.

Jan 1, 1932

By J. L. Zakin, G. K. Patterson, J. M. Rodriguez

Correlation has been obtained between drag-reducing characteristics for turbulent flow in a pipe and measurable properties of several polymer solutions. Several concentrations of high molecular weight polymethyl methacrylate in toluene, high molecular weight polyisobutylene in both toluene and cyclohexane, medium molecular weight polyisobutylene in cyclohexane and benzene and low molecular weight polystyrene in toluene were studied. Data obtained in these nonpolar solvents and literature data for more polar solvents were successfully correlated as the ratio of measured friction factor to purely viscous friction factor vs the modified Deborah number vrl/D0.2 where 71 is the first-mode relaxation time of the solution estimated by the Zimm theory. A shift factor which is a function of intrinsic viscosity 1/(4[?] - 1) allowed all the data obtained with nonpolar solvents to be correlated as a single function. For these systems, most of the data fit a single curve to within + 5 percent of the average friction factor ratio. The shift factor did not give a unique function of the data for the more polar systems. INTRODUCTION The phenomenon of drag reduction in polymer solutions was first studied by Toms1 in dilute solutions of polymethyl methacrylate in mono-chlorobenzene. The drag ratio for flow through circular tubes has been defined2 as the ratio of the pressure. drop of the solution to the pressure drop of the solvent at the same flow rate. The drag ratio is less than 1.0 for a drag-reducing fluid. Practical use of drag reduction is being made in fracturing operations in the petroleum industry.3 A more fundamental quantity is the friction factor ratio, defined as the ratio of the observed pressure drop to that predicted for a solution of the same viscosity characteristics and density at equal flow rates using the Dodge-Metzner friction factor equation4 Viscous solutions with drag ratios greater than 1.0 can have friction factor ratios less than 1.0. For practical applications, it is drag reduction which is of interest. However, for correlation the fundamental ratio is the friction factor ratio. In recent years, drag reduction has been studied extensively. Recent studies have shown that reasonable predictions of the incipience of drag reduction in polymer solutions can be made from the properties of the solutions and the flow Variables.5 However, it has not been possible to predict accurately the amount of drag reduction to be expected for a given polymer solution without any drag-reducing turbulent flow data on the same solution.6 For flow through circular tubes it is well established that there is a concentration effect and a diameter effect on drag reduction. Toms1 observed that drag reduction increases with an increase in the concentration of the solution up to an optimum concentration beyond which, due to the increased viscosity of the solutions, the drag ratio increased with an increase in concentration. Hershey 7 observed that for dilute Newtonian polymer solutions in nonpolar hydrocarbon solvents, a normal transition region may be obtained followed by a departure from the von Karman equation (on a friction factor-generalized Reynolds number chart). The point of departure is a function of diameter: the smaller tubes depart at the lower Reynolds numbers. Concentrated solutions may show no abrupt transition region, but merely an

By J. L. W. Birkinbine

This paper is a discussion of a part of the mineral wealth of the States of Oaxaca and Paebla, Mexico. It does not refer to the precious metals, sonie mines of which, in these States, are said to have been worked before the advent of the Spanish conquistadores in the sixteenth century, as my purpose is to invite attention to the exploration of deposits of coal and iron-ores in the Mixteca region. The prominence given to coal is warranted by the great effect of the scarcity of fuel upon the industrial development of Mexico. Under the progressive administration of President Porfirio Diaz, the Republic has made wonderful advances in the past three decades; and this progress would have been greater but for the limitations imposed by expensive fuel. In the spring of 1906 I was detailed by the Birkinbine Engineering Offices, of Philadelphia, to accompany A. B. Adams, of New York, in a reconnoissance of reported deposits of iron-ores in the State of Oaxaca. The result of this expedition was the formation, in 1907, of the Oaxaca Iron & Coal Co., of which Mr. Adams became, and has remained, President and General Manager, and I have spent the past three years as Chief Engineer of this company in Mexico, principally in western Oaxaca, where field-headquarters were established. GEOGRAPHY AND POPULATION. Although the geographical and topographical features of the Republic of Mexico are well known, few realize that the majority of its population is domiciled in the States which immediately surround the capital city of Mexico, including the Federal District, Mexico, Tlaxcala, Morelos, Puebla,

Jan 1, 1911

By David W. Brunton

The list of our past-Presidents comprises the names of many who, in their official addresses, have sketched the current progress of the arts and professions with which they were familiar. Such addresses are, in my judgment, highly useful, setting forth the results of our own work as a society, and recalling to our minds the particular lines in which discussion would prove most fruitful. Following this course with some hesitation, I venture to offer an outline of the recent improvements and the present situation in mining and metallurgy in the Western United States. The wonderful advances in mechanics, chemistry, and electricity have all combined to aid these arts to such an extent that progress during the last decade has undeniably been more rapid than ever before in the history of the profession. In all mining countries improved transportation-facilities, in many instances called into existence by the traffic created by the mines themselves, have done much to enlarge the field of operations by the reduction of freight-, operating- and living-expenses, thereby bringing lower-grade properties into the producing class. Under normal conditions, as the age of a district increases, all these different factors should combine to off-set the augmented costs attendant on deep mining, and greatly tend to prolong the profitable life of the mines. The more recent and important improvements in our Western mining-practice which have contributed most towards the advancement of the art may be briefly summarized as follows; but, before beginning this portion of my address, I wish to thank most heartily the many engineering friends who have so

Jan 1, 1910

By Joseph W. Roe

MaNY questions arising in the work of the mining engineer may be solved quickly and with suffcient accuracy by the methods of descriptive geometry; but, unfortunately, this subject is more often considered from a mathematical view-point than as an effective tool for solving practical problems. Some of the principles involved are merged into the ordinary operations of mechanical drawing, and are used unconsciously by the engineer in his every-day work. The rest are stowed away on the book-shelf with his forgotten or rarely-used college text-books. One reason for this condition of " innocuous desuctude " may lie in the uifortunate and often cumbersome notation which it has been found necessary to introduce. If some of these principles can be recalled to the engineer's attenti011 in terms of' every-day use they may prove of practical hearing. Recently, in talking with several mining engineers, I used some of the drawing-room methods of a machine-designer, to the evident surprise of those around me. These men were perfectly familiar with the methods, but their application to mining-work had not occurred to them. At their suggestion the present paper is offered, not in ally way as a treatise, but merely to suggest a certain point of view, in hope that it may lead others far more familiar with mining-problems to pursue the subject further. I. To Find the Strike. As the simplest and most fundamental problem, let it be required to find the strike of a vein when the location and elevation of three points on the outcrop are known. It mill be assumed for the present that the rein is a plane.

Jan 1, 1911

By Merlin H. Aylesworth

THE subject assigned to me is peculiarly appropriate to the anniversary of the birth of Abraham Lincoln. If we applied to our present problems the ideals and methods of the Great Emancipator, the future of American institutions would be so definitely assured that there would be little need to discuss the matter. The only inquiries would relate to the pace of progress, not to the possibility of progress. As a nation we have grown more and more to revere the memory of Lincoln, to honor his character, to extol his teachings and to eulogize his concepts of democracy. We rec-

Jan 1, 1940