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By Jay R. Burns

Two magnesium sand-casting alloys are commonly favored in the United States. These are referred to as H and C alloys (Dow Chemical Co.) or AM265 and AM260 alloys (American Magnesium Corporation). Both are of an aluminum-zinc-manganese type. H alloy contains 6 per cent aluminum and 3 per cent zinc and is characterized by relatively good toughness. C alloy contains g per cent aluminum and 2 per cent zinc and is employed where high yield strength and pressure tightness are required. Examination of magnesium castings poured in Europe and England,1,2 however, demonstrates that H and C alloys are replaced by A8 and AZ91, respectively. That is, A8 represents a magnesium alloy having superior toughness while AZ91 is suitable for high yield strength and pressure-tight applications. The basic difference between the American and European alloys is that the foreign alloys employ a somewhat higher aluminum content and less zinc than is found in H and C alloys. The mechanical properties of the alloys, when divided into high and low-aluminum groups, are quite similar, as determined from separately cast foundry-control type test bars.3 In this paper the decrease of mechanical properties caused by any given amount of microporosity is measured for H, C, A8, and AZ91 alloys. The relative susceptibility of each of the four alloys to microporosity is also determined. Typical mechanical properties and nominal chemical analyses are reported in Table I. [ ] The apparent similarities between the two alloys in each group have led to considerable discussion as to the relative merits of each of the compositions.2 Popular points for comparison between the alloys have been the relative susceptibility of each of the four alloys to microporosity5 and the effect of this microporosity on their mechanical properties. It is primarily intended, in this paper, to show the

Jan 1, 1946

By Charles R. Keyes

Continued discussion of the paper of Charles R. Keyes, Trans., xxxix., pp. 139 to 169, 850 to 856, and Bulletin Ho. 34, October, 1909, pp. 945 to 947. CHARLES R. KEYES, Des Moines, Iowa (communication to the Secretary*):-It is with pleasure that I acknowledge the value and interest of the historical notes on early mining at Lake Valley, contributed by Messrs. MacDonald and Courtis. In my own paper there was no attempt to enter into this phase of the subject; partly for reason that the intention was to take up this in detail in another connection, partly because there was not space enough to. devote to it in a brief geologic paper, and partly on account of the fact that the strictly mining features are quite distinct from the purely geologic characteristics. As may be inferred from its perusal, the brief historical paragraph prefacing my paper was in reality geologic in its bearing. The events referred to therein relate to the published information concerning the geologic structure. The personages principally mentioned were noted merely to show how the names of several of our most distinguished scientists came to be closely associated with that of Lake Valley. Far from my intentions was it to slight the memory of any , of that brave band who, with lives in their hands, took so active a part in the early development of the mines. The value of their records is perhaps much greater than that of any published notes. The narratives of Messrs. MacDonald and Courtis are as thrilling as many other experiences related of that time and place. Few of us at the present time can appreciate the dangers of that early day, when the fierce Apache all but swept the. white man from that part of the country, when renegades from Texas overran the land, and when the outlaws of the nations took their last stand before advancing civilization. In marked contrast do we to-day reach Lake Valley by means of the 11 iron horse"; and out of a luxurious Pullman

Apr 1, 1910

By K. E. Manchester, A. H. Clark

Hall measurements have been made on three groups of silicon samples, which were implanted with boron, aluininunz, and phosphorus ions. Boron and phosphorus implants show essentially bulk properties when annealed under previously determined conditions, i.e., 15 min at 80O°C for boron and 10 mirz at 600°C for phosphorus. Bulk properties were also observed in alu?rrilzum-implanted samples when ion concentrations were below 1015 cm-'; however, strange low- terrzperalure behavior and a falloff in cavrier concenlralion was observed for sarnples with ion concenlration abozle loL5 ern-'. This can be attributed to solid-solubility effects since the average bulk concentration f0.r the sample exhibiting bulk properties was below the reported solubility limit for aluminum, while the other samples were above the limit. A detailed study of the annealirzg process indicates that mobilities reach bulk c~alues in phosphorus implants at 250DC, in alutninurn ivnplanls a1 500°C, and in boron implants at 700°C. A simple rnodel has been proposed to fit the annealing data. THE technique of semiconductor doping by direct injection of energetic ions is being actively investigated at this Center. Previously published results from this laboratory have been concerned with the investigation of implanted profiles in silicon and the electrical properties of the resultant p-n structures.1'2 Diode properties have been reported for junctions produced by implantation of boron ions and aluminum ions in n-type silicon and phosphorus ions in p-type silicon. Reverse current characteristics, as well as electron diffraction data, have indicated that the damage to the structure produced by the energetic ions during the stopping process can be minimized by a gentle anneal. The time-temperature conditions for this process have been determined by sheet resistivity studies.3 Electrical profiles of implanted phosphorus ions which have been determined by a differential sheet conductivity technique are based on the assumption that the carrier mobilities and activation energies for ionization are the same as in bulk silicon. These assumptions have been substantiated experimentally by measurement of Hall constants and resistivities of these implanted structures and the results are presented herein. After establishing the bulk property equivalence of the annealed layers, a more detailed examination of the annealing process was undertaken. The sheet resistivity technique initially used to determine anneal conditions has been broadened to include Hall constants and mobility behavior with anneal conditions. PROCEDURE The three groups of samples prepared for Hall measurements were implanted with mass-separated beams of boron, aluminum, and phosphorus ions. Ion concentrations are equivalent surface concentration and they have been determined from beam current measurements during implantation. Implant conditions for the samples are shown in Table I. In all cases, the samples had previously been angle-lapped on one edge and the junction delineated with an HF-copper sulfate solution. The surfaces of the implanted regions of the samples were exposed to the delineating solution and in the case of the "n"-type phosphorus-implanted areas it was later discovered that a finite amount of surface could be etched by this solution. This is discussed in the section on results. The implanted samples were ultrasonically cut into the conventional six-probe configuration shown in Fig. l.* In the annealing studies, for which the meas- urements were taken at room temperature, the sample holder was a Bakelite jig incorporating tungsten mechanical probes. The other measurements were taken using a conventional liquid-nitrogen cryostat, in which the temperature could be varied from 77" to about 400°K. For these measurements, 10-mil aluminum dots were evaporated onto the samples and alloyed with the silicon at 530°C for 15 min. The samples were then mounted in flat-packs, and gold wires were bonded to the aluminum dots. The electrical measurements were made with either a Leeds & Northrup K-5 Potentiometer, a Keithley 147 Nanovolt Null Detector, or a Keithley 601 Electrometer. No external bias was applied to the substrate. There is an inherent self-biasing arrangement at one or the other of the current contacts (depending upon the polarity), and this suffices to limit the current flow to the implanted layer. The magnetic field was generated by an A. D. Little electromagnet. Except for occasional checks of linearity of the Hall voltage with

Jan 1, 1969

By Walter E. Heinrichs

The following is a condensed version of an open letter addressed to Bil Gilbert of Sports Illustrated: Your article, "When a Law Fights a Law, Sports Illustrated. April 26, 1971, betrays considerable unfamiliarity with the subjects of ecology, social science, mining law and history. In a magazine as widely circulated as Sports Illustrated, an article of such a slanted nature misleads the general public.

Jan 1, 1971

By W. A. Bruce

Studies of reservoir behavior of 12 Smackover limestone oil and condensate pools are presented. Buckner, Midway, McKamie, Magnolia, Mt. Holly, Schuler (Reynolds) and Village are treated in considerable detail and subjected to analysis with an electrical device for analyzing reservoir behavior. Results and comparisons of these analyses are presented. In addition to these reservoir-behavior studies, an attempt is made to assemble trans-missibility and storage data on the Smackover limestone formation from cores and logs taken in dry holes and producers. This together with the behavior of individual reservoirs leads to a better understanding of the formation as a porous aquifer. The ultimate purpose of this type of study is to improve predictions concerning the future behavior of these pools in such a system. Predictions are presented for several pools. Introduction In 1937 the Phillips Petroleum Co. drilled its J. D. Reynolds No. I to the Smackover limestone formation at Snow Hill, Arkansas. This well found oil in the porous, permeable, upper part of the Smackover, thereafter referred to as the Reynolds lime. Since then, six oil pools and six condensate pools have been discovered in the Reynolds lime, and more than 75 dry holes have explored parts of this formation. By the first of 1943, 44 million barrels of oil and 83 billion cubic feet of gas had been withdrawn from the various reservoirs. The original reserves estimated by the Arkansas Oil and Gas Commission were 342 million barrels of oil and rzoo billion cubic feet of gas. So far all of the production has been from anticlinal structures, most of which are asymmetric and have their axes roughly perpendicular to the dip of the formation top. This is indicated in Fig. I, which shows the pools, dry holes drilled, and contours on top of the Smackover.' These pools are of particular interest for reservoir-behavior studies because the production and drilling has been controlled, and in most cases the records of reservoir data are complete. In addition to the excellent production and pressure information available, more than one half of the wells drilled were cored and all of them were electrically logged. All of the pools show evidence of water drive. While this paper is in a sense a collection of reservoir-behavior studies for several different pools, there has been an attempt to go one step further and to show the importance of the iormation as a porous continuum or a single aquifer in which the withdrawals of fluids from any pool has an important effect on the behavior of all of the pools. An effort will be made to show that the water drives of these pools are dependent upon a much larger area of the Smackover limestone than that occupied by the petroleum accumulations.

Jan 1, 1944

By W. A. Bruce

Studies of reservoir behavior of 12 Smackover limestone oil and condensate pools are presented. Buckner, Midway, McKamie, Magnolia, Mt. Holly, Schuler (Reynolds) and Village are treated in considerable detail and subjected to analysis with an electrical device for analyzing reservoir behavior. Results and comparisons of these analyses are presented. In addition to these reservoir-behavior studies, an attempt is made to assemble trans-missibility and storage data on the Smackover limestone formation from cores and logs taken in dry holes and producers. This together with the behavior of individual reservoirs leads to a better understanding of the formation as a porous aquifer. The ultimate purpose of this type of study is to improve predictions concerning the future behavior of these pools in such a system. Predictions are presented for several pools. Introduction In 1937 the Phillips Petroleum Co. drilled its J. D. Reynolds No. I to the Smackover limestone formation at Snow Hill, Arkansas. This well found oil in the porous, permeable, upper part of the Smackover, thereafter referred to as the Reynolds lime. Since then, six oil pools and six condensate pools have been discovered in the Reynolds lime, and more than 75 dry holes have explored parts of this formation. By the first of 1943, 44 million barrels of oil and 83 billion cubic feet of gas had been withdrawn from the various reservoirs. The original reserves estimated by the Arkansas Oil and Gas Commission were 342 million barrels of oil and rzoo billion cubic feet of gas. So far all of the production has been from anticlinal structures, most of which are asymmetric and have their axes roughly perpendicular to the dip of the formation top. This is indicated in Fig. I, which shows the pools, dry holes drilled, and contours on top of the Smackover.' These pools are of particular interest for reservoir-behavior studies because the production and drilling has been controlled, and in most cases the records of reservoir data are complete. In addition to the excellent production and pressure information available, more than one half of the wells drilled were cored and all of them were electrically logged. All of the pools show evidence of water drive. While this paper is in a sense a collection of reservoir-behavior studies for several different pools, there has been an attempt to go one step further and to show the importance of the iormation as a porous continuum or a single aquifer in which the withdrawals of fluids from any pool has an important effect on the behavior of all of the pools. An effort will be made to show that the water drives of these pools are dependent upon a much larger area of the Smackover limestone than that occupied by the petroleum accumulations.

Jan 1, 1944

By F. P. Dewey

The Falling Cliff Mine adjoins on the west the Bertha Mine, from which a large amount of first-class ore has been taken, producing the purest zinc known to commerce. The two mines are in the same hill, Bertha being on the northern slope and Falling Cliff on the toy and opposite slope. The formlation is No. 2 limestone. Although considerable exploration has been clone by numerous shafts and' tunnels (there being over six hundred feet of the latter), no satisfactory determination of the dip and strike of the vein could be made on account of its contortions, the ore descending from the top to the bottom of the tunnels and rising again in very short distances ; but enough has been done to indicate a very large mass of

Jan 1, 1882

By C. R. Hocott

THE viscosity of the oil in the reservoir is one of the properties that influence its movement through the sand to producing wells. Measurements of viscosity, therefore, are pertinent to problems associated with well behavior and with the estimation of recoveries, and afford an indirect means for partial evaluation of various methods of controlling reservoir behavior. The effect of dissolved gases on the viscosity of crude oil has been determined,1,2 but no data have been published on the viscosity of repre-sentative samples of reservoir oils. This paper describes a simple instrument that has been used to determine the viscosities of a number of subsurface oil samples at the temperatures and pressures existing in the reservoirs, and presents the results of the determinations for typical fields.

Jan 1, 1940

By C. R. Boyd

It would be a quite congenial task to attempt to describe all that extraordinary mineral wealth which is now giving such prominence to the region from the James River to the Tennessee line: adjacent to the great lines of the Shenandoah Valley and the Norfolk and Western railways; but such a task would be impossible within the limits of any ordinary paper. Hence, in advance of the fifth edition of my book and map on the Resources of Southwest Virginia, I must restrict myself to a limited but most interesting subdivision of this remarkable mineral belt.

Jan 1, 1884

By H. C. Jennison

Two distinct types of defects occur at times in copper wire as a result of the use of dies of improper design or undesirable wire-drawing practice. The conditions under which these defects may be produced, as well as precautions to be taken in order to prevent them, have been known to The American Brass Co. for many years. The quality of the copper wire bars and rods has too often and unjustly been held responsible for these particular defects and it is to correct any such belief that this paper is presented. An extremely high quality of electrolytic copper has been supplied to the trade by all refineries for the last 20 years at least. The purity of the copper would average well above 99.900 per cent. The casting of the wire bars has been handled in a generally satisfactory manner. The bars have been cast sound, with a flat to slightly crowning set and have been free from sloppy edges, cold sets, etc. In other words, the wire bars have met A. S. T. M. specifications and have been generally satisfactory. For the most part, they have been everything that could be desired from a quality standpoint yet most of the wire mills in this country and in Europe have at times held the quality of the copper responsible for the two types of defects described in this paper. As a matter of fact, these defects are produced entirely in the wire mills. The author has visited many of the large wire mills in the United States and in Europe to investigate these defects. In some cases the trouble has been so serious that the wire mill has ceased operations. At times the wire mills are reluctant to believe that they are responsible for the defective product. The effect of die design, wire-drawing practice, etc., upon the quality of copper wire has received' little study on the part of wire mills, particularly those that have commenced operations in the last few years.

Jan 1, 1930

By Stewart R. Wallace

Members of the Society, it is a very great honor for me to be here today and to have the opportunity of telling you about some things that have been accumulating in the back of my mind for some time. Before attempting to do so, I should acknowledge my debt to the many people who are responsible for my presence here this afternoon. To do this properly, however, would consume much of my allotted time and I will therefore mention only two men, both of whom were directly involved in the discovery of the Henderson ore body. The first of these was Robert Henderson, now dead, who at the time the work was going on was vice president of Western Operations of the Climax Molybdenum Co. Truly, he provided the environment that permitted the exploration program to function effectively, and the deposit appropriately bears his name. The second man I meant to mention was resident geologist at Urad at the time of the Henderson discovery. I think I should explain right here that the Urad ore body and the Henderson ore body, although entirely separate, are closely related deposits, and that both are located at Red Mountain in Clear Creek County, Colo.

Jan 6, 1975

By Alfred Heggem

IT is the purpose of this article to describe methods recently introduced into the oil and natural gas industry to safeguard the lives of the workmen and to protect property from destruction. Only such drilling methods are described as pertain directly to the operations necessary to maintain the well under complete control at all times. Wells Formerly Drilled Without Controlling Equipment It may seem incredible that practically all wells, until recently, were drilled without the provision of any means for control. To drill a hole into a boiler carrying high-pressure steam without first providing means to control the escape of steam would be unthinkable, yet in oil fields wells are drilled into a gas or oil formation with a possible pressure of 300 to 1,800 lb. per square inch and a daily flow of 20,000,000 to 80,000,000 cu. ft. of gas or 1,000 to 15,000 bbl. of oil per day. Some wells have produced in excess of 100,000 bbl. of oil per day, but these are exceptional cases. In addition to the loss of product, one must consider the great danger attendant upon the promiscuous liberation of such an amount of explosive and inflammable substance.

Jan 1, 1916

By J. Versluys

When a well strikes an oil-bearing layer, the oil has a pressure which is generally sufficient to enable it to rise to near the surface (sometimes above the surface). As soon as a well begins to produce, however, the liquid moves through the pores of the reservoir bed and the pressure in the well becomes much lower than the pressure originally prevailing there. At some distance from the well, however, the pressure in the reservoir bed remains unaltered; thus the pressure of the oil has not only to lift the oil, but also to overcome the friction resistance in the pores. The fact that so many oil wells are gushers is a consequence of the energy accumulated in the gas. In gushing the well acts as a gas-lift. A mixture of liquid and gas (the latter partly dissolved in the former) rises vertically from the oil-bearing layer through a cylindrical casing to the surface. In time conditions alter and the well ceases to gush regularly, then the gushing can be further promoted by inserting a narrower tube in the well and connecting the top of the oil string to the tubing. If the action in time becomes irregular, the gushing can be kept up for a further period by forcing gas between the two tubes. In the oil fields the term "gas-lift" is used actually only where extraneous gas is applied, as in the last of the stages mentioned. The action, however, is just the same whether the gas exclusively originates from the formation, or is partly applied artificially. Thus by gas-lift we simply mean a vertical tube in which the energy of gas under pressure, and of dissolved gas, is utilized for raising a liquid. In gushing oil wells the pressure is frequently very high and the absorption coefficient 0.4 (expressed in vol. ratio) of the coexisting gas is not particularly high, so that in reality it should be assumed that a considerable portion of the gas, at any rate at the bottom of the gas-lift, is dissolved in the oil. For water-producing wells this is not usually of such importance. Where the volume of the flowing gas is much greater than that of the flowing liquid, the latter can be suspended in the former in the form of

Jan 1, 1930

By R. A. Anderson, T. E. Tietz, J. E. Dorn

Recent investigations1,2,3,4 have conclusively shown that the strain hardened state of metals depends upon the temperature and strain rate of pre-straining as well as on the total plastic strain. A typical example of the effect of temperature of prestraining on the work hardening of metals is reproduced in Fig 1. When pure aluminum is strained at liquid nitrogen temperature the upper solid stress-strain curve (OFGH) is obtained. But when pure aluminum is prestrained to e2 = 0.153 at atmospheric temperature and the test is then completed at liquid nitrogen temperature, the curve OBCD results. Thus a prestrain E2 = 0.153 at atmospheric temperature gives a flow stress C when continued at liquid nitrogen temperature, whereas a higher flow stress G results when the specimen is strained exclusively at liquid nitrogen temperature to the same strain E2. Consequently the metal strain hardens more rapidly at the lower temperature. Obviously the strain alone is not a measure of the strain hardened state in metals. Inspection of Fig 1 reveals that the flow stress at C is identical with that at F. This fact suggests that a strain E2 = 0.153 at atmospheric temperature induces the same work hardened state as a strain E1 = 0.058 at liquid nitrogen temperature. But this concept of equivalent strains is also in error. If curve CD is shifted to the left so that point C falls on F, point D becomes D'. Inspection of the curves reveals that the rate of increase of stress with strain at C is greater than the rate of increase of stress with strain at F even though the flow stresses are identical. Consequently C and F do not represent identical work hardened states. It therefore becomes important to ascer- tain how the strain hardened states at C and F might differ from each other. In a more recent report1 it was shown that straining at higher rates of strain increases the amount of strain hardening in a manner quite analogous to straining at lower temperatures. These observations suggested that the flow stress is not only a function of the strain but also a function of the strain rate-temperature history of straining, perhaps in accord with the Zener- ?H Hollomon parameter p = Ee /RT (where

Jan 1, 1950

By M. King Hubert

The growth of human knowledge is an evolutionary process. Historically our separate sciences came into existence as people became interested in various apparently unrelated domains of phenomena, and in this manner we acquired the sciences of physics, chemistry, astronomy, biology and geology. As various of these sciences became established, cognizance of them came to be taken by the universities and in this manner there arose the traditional departments of physics, astronomy, chemistry, biology and geology of our American universities. As there was no particular rationality in the boundaries separating the various sciences, in the university departments the jurisdiction of each has assumed quite arbitrary limits. In the domain of earth phenomena the first science to grow up was that of geology, which arose originally from the activities of the collectors of rocks, minerals and fossils. Thus geology evolved as a descriptive science dealing with directly observable terrestrial phenomena for which elementary rational explanations were offered. The traditional treatment of phenomena by the science of geology has rarely been with more than an elementary regard for the fact that these phenomena were also phenomena of physics and chemistry. Since the latter part of the nineteenth century, a new approach to terrestrial phenomena has been emerging and becoming of so great a significance that it can no longer be ignored. This approach has been made by people trained primarily in the sciences of physics and chemistry, who have investigated terrestrial phenomena as constituting phenomena of their respective sciences. In this manner we have acquired the so-called "borderland sciences" of geophysics, the physics of the earth, and of geochemistry, the chemistry of the earth. Neither of these fields is new, having arisen chiefly at the hands of European investigators during the latter part of the nineteenth century. The European universities have long since given official recognition at least to geophysics, by the establishment of departments or institutes of geophysics, which are on a par with the university departments of the other sciences.

Jan 1, 1940

By M. King Hubert

The growth of human knowledge is an evolutionary process. Historically our separate sciences came into existence as people became interested in various apparently unrelated domains of phenomena, and in this manner we acquired the sciences of physics, chemistry, astronomy, biology and geology. As various of these sciences became established, cognizance of them came to be taken by the universities and in this manner there arose the traditional departments of physics, astronomy, chemistry, biology and geology of our American universities. As there was no particular rationality in the boundaries separating the various sciences, in the university departments the jurisdiction of each has assumed quite arbitrary limits. In the domain of earth phenomena the first science to grow up was that of geology, which arose originally from the activities of the collectors of rocks, minerals and fossils. Thus geology evolved as a descriptive science dealing with directly observable terrestrial phenomena for which elementary rational explanations were offered. The traditional treatment of phenomena by the science of geology has rarely been with more than an elementary regard for the fact that these phenomena were also phenomena of physics and chemistry. Since the latter part of the nineteenth century, a new approach to terrestrial phenomena has been emerging and becoming of so great a significance that it can no longer be ignored. This approach has been made by people trained primarily in the sciences of physics and chemistry, who have investigated terrestrial phenomena as constituting phenomena of their respective sciences. In this manner we have acquired the so-called "borderland sciences" of geophysics, the physics of the earth, and of geochemistry, the chemistry of the earth. Neither of these fields is new, having arisen chiefly at the hands of European investigators during the latter part of the nineteenth century. The European universities have long since given official recognition at least to geophysics, by the establishment of departments or institutes of geophysics, which are on a par with the university departments of the other sciences.

Jan 1, 1940

By R. W. Raymond

Recent literary labors have led me to the compilation of the following tables and estimates, which may possess interest for my colleagues in the Institute, and which are here submitted without comment.

By M. M. Fine

THE results of a research and development lab- oratory and pilot-plant mineral-dressing investigation by the Bureau of Mines of the complex copper-lead-cobalt-nickel ores of southeast Missouri are reported in this paper. This investigation, in cooperation with the National Lead Co., showed that separate concentrates of lead, copper, and cobalt-nickel could be made by fine grinding and flotation. An industrial plant built subsequently by the St. Louis Smelting and Refining Div. near Fredericktown, Madison County, Mo., produced such concentrates during the war years. Present commercial production at the mill is limited to lead and copper concentrates, but research to permit economic utilization of the cobalt and nickel values is continuing.

Jan 7, 1951

By J. T. Norton, J. G. McMullin

E. R. JETTE*—The way this ternary was developed there are two directly determined points on each of the iso-thermals except the 700° isothermal, where I believe there is only one. How were the end points determined, and what was the basis for it? Whose work formed the basis for the silver copper line ? M. B. BEVER †—At most temperatures the authors determined three points of the isothermal line. For example it can be seen from Fig 3 and 4 how three points for the 600°C contour line were obtained. The authors took two additional points for each temperature from the copper-silver binary diagram contained in Hansen's volume on constitution diagrams. It is correct that the 700°C contour line is based only on one point in the ternary field which was found by a slight extrapolation of Fig 4. R. I. JAFFEE*—Are the tie lines representing phases in equilibrium parallel to the silver-copper boundary ? M. B. BEVER—Are you asking that as a matter of principle ? R. I. JAFFEE—I assumed that would follow from principle. I wonder if that is in accordance with the authors' ideas too. M. B. BEVER—I do not believe the authors obtained any information on the tie lines in the two-phase field. Of course, in the limiting case of very low gold contents the tie-lines approach to the silver-copper boundary, but generally in the two-phase field I do not think that the tie-lines have to be parallel to the boundary. E. R. JETTE—I am quite sure they do not have to be parallel. You cannot tell from this work in which direction they go. E. A. GULBRANSEN*—Were any pycnometric measurements made to check the lattice parameters of the alloys ? M. B. BEVER—I did not hear any-

Jan 1, 1950

By B. F. Bush

The coal-fields of Missouri, situated in the northern and western portion of the State, are distributed, in whole or in part, over 57 counties, embracing an area estimated by Mr. Broad-head' to be practically 23,000 sq. miles, including small detached beds and outliers in St. Louis, St. Charles, Lincoln and Warren counties in the eastern part of the State. This area includes about 8,000 sq. miles of Upper or Barren Measures, 2,000 sq. miles of exposed Middle, and 12,420 sq. miles of exposed Lower Measures. In a general way, the Missouri coal-field is bounded on the east by an imaginary line entering the northern part of the State just east of the 92d Meridian and passing across the State in a southwesterly direction to a point on the Kansas-Missouri line a little below the southern boundary of Barton county. An important part of the field overlaps this line and extends down the northern side of the Missouri river, underlying the greater part of Randolph, Howard, Boone and Audrain counties. In all, 34 counties produced coal during the year 1903. Fig. 1 shows the position of the coal-fields in Missouri. Geological Features. The Coal Measure formations, all of the Carboniferous age, rest unconformably upon the rocks of the sub-Carboniferous or Mississippian series, and, in some cases, upon the rocks of the Devonian and Silurian ages. From their outcrop on the eastern and southeastern borders of the field, the Measures dip west to northwest at the rate of 10 ft. per mile, reaching a maximum thickness estimated by

Jan 1, 1905