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By G. F. Tagg

Earth-resistivity measurements are often of service in obtaining information regarding geological formations, particularly when applied to structural problems. In such problems the masses of the various bodies are large, and have a corresponding effect on the average resistivity of the soil. Much work has been done using such measurements, but in general the method of interpretation employed is empirical. Since certain simple cases can be investigated mathematically, it appears to be quite sound to endeavor to apply the mathematical solutions to the practical results, in order to deduce from the latter such unknown quantities as depth. This paper deals with such a method of interpretation for the simple case of a single horizontal stratum. In the method described by Wennerl for measuring earth resistivity, four stake electrodes are driven into the earth in a straight line as shown in Fig. 1. A current I amperes is passed between the two outer stakes and the potential difference V volts between the two inner stakes is measured. Then if a is the electrode separation, the specific resistance of the soil, which is assumed to be homogeneous, is given by the formula P = 2?v/1 [1] v or if v/1 is called a resistance R ohms, p = 2?aR [2] If a is in inches, p will be in ohms per inch cube, or ohm-inches, and if a is in centimeters, p will be in ohms per centimeter cube or ohm-centimeters. As stated above, this formula is true only if the earth is homogeneous, and when this is not the case an application of one of these formulas

Jan 1, 1934

By J. J. Kramer, W. A. Tiller, G. F. Bolling

The solidification of poly crystalline zone-refined lead has been examined. A novel casting technique was used, with several advantages such as unidirectional heat flow, atmosphere control, and decanting of the liquid during any stage of growth. The experimental results show the separate existence of two textures, a (111) surface texture at the chill surface and a texture in the columnar zone, in the absence of conditions which would produce dendritic growth. WALTON and chalmers have most recently shown that the dendrite direction is the preferred axial orientation for the solidification of many metals in casting. Experimentally, for aluminum and lead, they showed that in the columnar zone the dendrite direction, <l00>, predominated, developing from an equiaxed chill cast layer that exhibited no preferred orientation. A reasonable description of the way in which grains closer to the dendrite orientation were able to encompass other grains was then set forth. For their materials, it was also shown that high superheats could inhibit a preferred axial orientation from developing, presumably by inhibiting dendrite growth. The observations of Rosenberg and iller, on the other hand, showed that zone-refined lead, cast under conditions similar to those of Walton and halmers,&apos; had a definite <111> texture in the columnar zone. However, no examination was made of the chill surface to find out if the columnar zone texture was independent of the orientations at the surface. Since the existence of preferred growth in Upure" lead is thus in doubt, a reexamination of the casting of zone-refined lead is presented here, using a novel casting technique. EXPERIMENTAL PROCEDURES AND RESULTS Zone-refined lead was prepared from two starting materials;99.999+pct supplied by ASARCO, and 99.999pct supplied by COMINCO. The manner of zone-refining and the phenomenological tests for purity after refining, have been describedelsewhere.&apos; The casting apparatus is shown schematically in Fig. 1. The following general procedure was used: The metal was cut directly from the best parts of

Jan 1, 1963

By L. M. Pidgeon

The reactive metals are above manganese on the electromotive series. Their compounds are characterized by large heats of formation and they cannot be reduced from their ores by classical methods. Three general production methods have been used: a) Fused salt electrolysis, b) reduction of a halide by another metal, and c) reduction of the oxide by another metal. Method (a) is highly developed, as in the case of aluminum, (b) in the case of titanium, and (c) has been successful in the case of volatile metals such as magnesium and calcium. It is suggested that future improvements will take place in (a), and particularly in (c), but are rather less likely in the case of (b). THIS year of 1963 is the centennial of the birth of both Charles Hall and of Heroult, the founders of the aluminum industry. Aluminum is the one reactive metal which has reached massive stature in modern industry and perhaps the only such metal to have been produced in any quantity before the turn of the century. It has been joined by others, some on a very modest scale, but all of importance and all of fascinating interest. When invited to give the Fifth Extractive Metallurgy lecture, it seemed appropriate to look back upon the short history of this group to trace the developments which brought extraction methods to their present state and, at great risk, offer opinions as to future trends.

Jan 1, 1963

By Henry D. Hibbard

These impurities are perhaps the most important things in steel—especially steel made by the oxidation processes—the effect of which has not been at least approximately determined. By oxidation processes I mean the Bessemer and Siemens-Martin, during which the metalloids in the charge are removed by oxidation. It has been truly said that it is a clear advantage to have a new name for a new thing. To secure this and to economize space, let us adopt the name sonim (plural sonims) to designate the solid non-metallic impurities existing in steel or other metal. I would define a sonim as a solid non-metallic portion of matter existing as an impurity in metal. A piece of sand, brick, clay, or such material, imbedded in metal, would be considered as a foreign body, not as an impurity, and therefore not a sonim. The studies of sonims of which the results have been published hitherto, have been made chiefly or wholly on finished ar at least on cold steel, without much, if any, regard to the specific methods by which the steel was made. While many of the results so obtained are valuable, they give little help in determining the cause, effect, or cure of&apos; the disease. It is not enough, in such a study, to know merely the commercial name of the process; for within the field of each process lies a great number of possible variations, each of which will yield a result differing in some respect from all others; and the control of sonims is particularly dependent on the metallurgical treatment of the metal, because of the inability of analytical chemistry to throw much light on their presence, condition, and effect, as they usually occur in conlmercial steels. The microscope aids more, perhaps, than chemistry in their study.

Jan 1, 1911

By B. S. Norris, Charles R. Austin

The stresses which initiate deformation processes in metals are fundamentally important in the study of the mechanical properties of metals. A point of inflection in the load-elongation curves obtained for single crystals&apos; has been rather too readily interpreted as a true yield point, and the critical resolved shearing stress on the plane of slip taken as a material constant. Even early work showed that the stress at this point varies with rate of loading, but it has not been generally appreciated that creep tests under static loads alone are suited for determining the existence or nonexistence of a yield point.* It has now been shown by Miller that single crystals of zinc3 when loaded statically begin to yield at loads too small to measure; as a result there is no case now known, apart from that cited in the present paper, in which a true critical stress for yielding has been demonstrated for single crystals of metals. The case of iron has especial interest: the existence of an upper and lower yield point and of an elongation at the yield point in ordinary iron and steel marks this substance as unusual, though the effects have been found to a very minor degree in other metals and alloys. $ Most alloys do not show such marked phenomena when appreciable yielding begins, and accordingly modern practice is to speak of the yield strength of such materials, a stress read from the load-elongation curve after elongation has begun, rather than yield point. The special behavior of iron suggests that it is more likely that single crystals of iron should have a true yield point than other metals. The study of the mechanical properties of metals and alloys requires a determination of the crystallographic mechanism of deformation, wlletller deformation proceeds by slip, twinning, or cleavage, or a combination of these, and a determination of the stresses that induce these modes of deformation. With this information, a study of the rates of work-

Jan 1, 1938

R,. P. JaRvis,* El Oro, Estado de México, México.—The practical problem raised by Mr. Wisser—that is, the determination of the lower limit of ore deposition, below which it is useless to look for ore shoots—is one of the most important in economic geology. He asks: "Can we learn to determine the position of such a line?" For individual districts, yes; but its determination has always been by empirical methods; that is by actually exploring the veins to such depths that the values drop below the economic limits. Usually the signs are plain enough that values have been bottomed without confirmation by the chemist or assayer. Most veins, when approaching their limit, begin to split into branches or stringers; the vein matter itself undergoes a change from "lively looking" rock to one that is dull and unpromising, the quartz, instead of having segregated into clean vein matter, has simply spread itself into the country rock, rendering this more siliceous but no richer—these, together with inclusions of the country rock in the vein, are all positive indications of the limit. Mr. Wisser seems disposed not to accept the law of cause and effect, which he calls "empiricism." He says: "Empiricism embodies an assumption perhaps not evident at first glance. It is this: that like effects spring from like causes and therefore necessarily have a common meaning." There can be no doubt as to the validity of this law, since it is the foundation stone upon which are built all inductive sciences, including economic geology. When demonstrable, proved facts become confused with inferences, as they seem to be generally in the paper under examination, no sound conclusions can be reached. Mr. Wisser has failed to give sufficient data covering the two vein systems which he cites as examples. Presumably they are situated in the Pachuca District of Mexico, but not everybody is familiar with the vein systems there in spite of the fact that it is world famous as a silver producer. Are these two systems separated some distance horizontally from one another and how far? He has given no estimate of the amount and kind of rock that has been eroded from over the present veins. His description of the two systems appears on page 100, beginning: "1. East-west veins," and ends on page 101, "they would lack spaces there in which to deposit." On page 101, with the paragraph beginning "On the other hand," he gives a picture of what he believes takes place in class 2 veins. The sum of this seems to be, according to Mr. Wisser&apos;s observations, that, in the east-west veins, class 1, there has been an invasion of an "altering solution," which I judge has been responsible for the formation of extensive "alteration haloes"; that these alteration solutions have followed along pre-existing fractures or fissures; and that after these alteration solutions finished their work the mineralizing solutions deposited the vein matter and metallic values. Mr. Wisser does not specify clearly what the "alteration haloes" consist of; in other words, what change the original rock has suffered, whether oxidizing, carbonating, or sulphidizing. If they came from depth they could not be oxidizing or carbonating, and in this case it is a bit

Jan 1, 1941

By Elliott J. Roberts

In spite of the fact that the percentage of true colloids in an ore grind is very small,&apos; these pulps exhibit many of the properties of true colloidal suspensions. A quartz particle, appreciably finer than 10 microns in diameter, has a settling rate so low that at a dilution of 5:l or over, the capacity of a settling tank to settle such particles would be uneconomical if the individual particle rate prevailed. However, by grouping the finer particles into aggregates or flocs, the settling rate can be increased to an economical value. The colloidal chemistry of pulp thickening is thus chiefly concerned with particles having diameters of between 1 and 10 microns, although particles as coarse as 40 microns in diameter are more or less involved. These particles must be associated in such a manner that they settle at an economical rate and give a clear, supernatant liquid or overflow. The treatment of the subject may be divided into three phases, cach phase having a more or less different colloidal aspect. The first phase is the problem of getting the pulp or suspension into the proper condition of flocculence; the second is the behavior of the flocculent pulp in its initial and intermediate stages of settling; the third is the behavior of the flocs in the find period of settling or thickening stage. Let us look first into the methods and mechanism of obtaining the flocs and then consider their behavior and properties. Flocculation Colloids are merely ordinary substances reduced to a very small particle size, the upper limit being placed by definition at 1 micron (0.001 mm.) diameter by the soil chemists and at from 0.2 to 0.1 micron by various other colloid chemists. The lower limit is reached only when the particles approach molecular dimensions. The term L&apos;colloid" should not necessarily imply lack of crystallinity. Particles as small as 0.01 to 0.02 micron give perfect X-ray patterns, while with 0.005 micron particles the bands on the powder photograph are merely broaderled and diffused.2

Jan 1, 1935

By P. H. Royster

IN a study of the blast-furnace process, the Bureau of Mines has made many experiments for the purpose of determining the exact nature of the combustion of coke in the neighborhood of the tuyeres. Two papers1 presented at a meeting of this Institute discussed somewhat the practical aspects of coke combustibility in its relation to the operation of the blast furnace. In a later paper,2 Sherman and Kinney discussed the possible effect of variations in the combustibility of cokes on the furnace operation, and find that the "reoxidation theory" of Koppers and the "heat concentration theory" of Brassert3 are insufficient to explain the variation in the conduct of different cokes that has been observed by furnace operators. In their report to the D-5 Committee of the American Society for Testing Materials, with which the Bureau of Mines has been cooperating, Perrott and Fieldner4 seem to agree with Sherman and Kinney that, for practical purposes, the nature of the combustion of coke at the tuyeres of any furnace is constant and is affected neither by the physical properties of the coke nor by the nature of the furnace operation. They omit as unimportant any tests on the combustibility of coke from their proposed methods for standard tests on coke. In the last two papers, it is pointed out that performance tests, in which all other factors except coke quality are kept constant, are to be desired and

Jan 3, 1924

J. L. JONES,* Pittsburgh, Pa.-If a nickel anode is cast under commer-cial conditions, will it contain nickel oxide? Will the nickel oxide affect the rate of corrosion in a double sulfate solution; or will the nickel oxide dissolve in a double sulfate solution? I would also like to ask whether a 98 per cent. pure nickel anode will corrode as fast as a 96 per cent. nickel anode; whether electrolytic nickel will corrode less rapidly than nickel containing a small amount of carbon; and whether the materials some-times used in coating molds for casting nickel anodes will affect the rate of corrosion of the anode? In other words, whether an electrically non conducting coating is likely to be present that will prevent the nickel anode from corroding rapidly. JOHN F. THOMPSON.-The nickel oxide will not dissolve in the double sulfate solution, as far as we know. We do not make the ordinary nickel anode of commerce, but we supply nickel to the nickel anode makers. Those makers almost invariably buy a high-carbon nickel shot, ranging around 0.45 per cent. carbon. In their process, they even further, car-burize it so as to get nickel that will melt easily and be fluid enough to fill the mold, so that the ordinary cast anode on the market is unquestion-ably oxide free. The only time that such an anode will have oxide will be through an error in melting. Some cupola makers of anodes have had trouble with oxidation, but as a rule the anodes are thoroughly carburized; so much so that they probably carry a couple of per cent. of carbon of which around. 1.6 per cent. is graphite.

Jan 12, 1919

Jan 1, 1920

By T. Egleston

THE manufacture of charcoal in kilns was declared many years ago, after a series of experiments made in poorly constructed furnaces, to be unprofitable, and the subject is dismissed by most writers with the remark that in order to use the method economically the products of distillation, both liquid and gaseous, must be collected. It is asserted with truth that the number of kilns required for a large production of iron would be so great that it is doubtful whether any works would be justified in making the necessary outlay for their construction, but it can also be asserted with equal truth that for any such production in a given locality the use of charcoal as fuel would be equally unjustifiable. It appears to have been forgotten that there were other manufactures besides iron in which large amounts of charcoal were used, but these consumers seem to have been guided entirely by the results of the experiments of the iron men, who necessarily made the largest quantity of it. Some authors speak in a doubtful way of the quality of the charcoal produced, and a few concede that with great care good charcoal can be made in kilns, but that most of the workmen do not like kiln charcoal. This is the real secret of the opposition to this method of manufacture. Most of these objections were written when charcoal was the most important fuel used by the iron manufacturer, and when what was a large production of iron for several furnaces was less than that produced by a single modern one, in localities where other fuels can be had. Almost all that has been written on the subject related to the use of the fuel for the manufacture of iron in the blast furnace, where very peculiar properties are required, and where the quantity produced is limited by the height of the furnace, and this in turn by the crushing resistance of the charcoal. A large production was, therefore, only possible when the best and hardest woods were used. Of all these objections there is not a single one which is not equally applicable to any method of charcoal manufacture, whether it be meilers, pits, or furnaces. Until recently, therefore, the manufacturers of charcoal iron * Read at the Pittsburgh meeting, May, 1879.

Jan 1, 1880

By V. R. Garfias R. V. Whetsel

Production of crude petroleum in Mexico during 1935 totaled approximately 40,082,000 bbl., an increase of 1,925,000 bbl. over the previous year. Successful development continued in the Poza Rica field during the year, increasing production in that area from 3,708,000 bbl. in 1934 to 9,542,000 in 1935. The output of the South fields (Golden Lane) area decreased by 3,000,000 bbl. during the year, and the heavy-oil district of the Northern fields by 1,500,000 bbl. Production in the Tehuantepec fields showed a slight gain. Production of natural gasoline increased from 430,000 to 600,000 bbl. in 1935. Crude run to stills in local refineries is estimated at 30,000,000 bbl., some 4,000,000 bbl. more than in the previous year. Exports of crude and refined products were approximately 22,000,000 bbl., or 2,000,000 bbl. less than in 1934. Exclusive of ships bunkers, domestic consumption increased about 900,000 bbl. during the year, reaching an estimated total of 14,500,000 barrels. Only 74 wells were completed, as compared to 148 in 1934 and 91 in 1933. In proven areas 58 completions resulted in 33 producers and 25 failures. In northeastern Mexico, near the United States border, six wildcat wells were completed, all of which gave little or no encouraging results, except Rancheria No. 3, near Camargo, which is a fair-sized gas well. Four wildcats were drilled just northeast of the Northern fields (heavy-oil district), all of which were failures. A deep test was completed a short distance southeast of the Golden Lane (South fields) in Palo Blanco, which encountered small production not sufficient to exploit. On the Isthmus of Tehuantepec a wildcat well was completed for an estimated initial production of 2000 bbl. daily, a short distance south of the old Jalapa field, which was perhaps the most important new development of the year. Four other wildcats drilled in the Isthmus district resulted in failures. Fields Northern Fields (Heavy-oil District).—In the Northern fields, 18 producing wells and 20 failures were completed, as compared to 34 producers and 71 failures in 1934. The initial production of the new

Jan 1, 1936

By L. L. McDaniel

ROLLER—As one who has been privileged to read Mr. Poland&apos;s paper before its publication, I wish to express high praise for it and the record which it gives of the work done by the Research and Development Department of Revere Copper and Brass Inc. in developing a satisfactory furnace for the recovery of metallic zinc from secondary metals by distillation. I have also had the opportunity of studying the operation of the furnace when running on scrap brass at the Detroit plant of Revere, and I can therefore say from knowledge gained first-hand that the unit is efficient and economical when used in conjunction with distillation. However, when I read what Mr. Poland has to say in reference to the possibility of using the furnace for melting copper cathodes for the production of oxygen-free and tough-pitch copper shapes, I am constrained to be somewhat skeptical. No doubt the furnace can readily be modified so as to make it possible to melt cathodes, but that is only a part of what is required to produce refinery shapes. Because of its construction the atmosphere in the furnace is highly reducing and even without protective gases such as nitrogen the copper cathodes which are

Jan 1, 1950

By D. Torrey

CONSIDERING the two great interests of to-day, in iron upon the one hand and steel upon the other, and recognizing with measurable distinctness the peculiar fitness of each for special services to which they are applied, the proposition to unite the two metals in combination, to bring into simultaneous use the peculiar advantages which each offers, has great attractions. The limited success which has been attained by trying to bring about such combinations of the two metals through the use of fluxes in welding, has led to the general adoption of the opinion that an effective union of the two metals is impracticable, or to the view that if practicable it would have but limited commercial value. Such opinions are, I think, premature and erroneous, and having gained some knowledge of the character and value of the "Wheeler process" for welding iron and steel without the use of fluxes, I submit the following observations and opinions of the matter for your information, with the hope of eliciting such a discussion of the subject as it may require. The principle of the invention is to bring the two metals simultaneously to a welding heat in one pile, and then to manipulate it.

Jan 1, 1879

By Basil Prescott

In the science of evolution of the species, there is a law which, simply stated, avers that the history of the individual repeats the history of the race. Similarly, if unassisted by the experience of others, each SUCcessful engineer would perfect and develop his methods and technique from the rough grab sample up to the carefully taken, recorded and studied samples and observations which now determine and decide the expenditure of the large sums required for modern mining. Hence real progress results from the interchange of experience, as in that way the entire experience of the profession can be made available to every engineer. The literature of this subject is already voluminous, but some progress has been made in the gathering of data and in their compilation or presentation. More Romance than Developed Ore in Limestone Deposits In certain types of deposits, methods little known 25 yews ago have been developed, perfected and standardized to a degree that lifts sampling from the field of manual labor to the plane of an applied science; for instance, the modern methods of estimating the so-called porphyry coppers. With some types of orebodies, we have become familiar, and sometimes on too easy speaking terms, with millions of tons of ore in reserve and tens of millions of dollars; while with others even these once marvelous figures sink into insignificance before the array of ciphers that are presented. .In such company, the average limestone replacement orebody is entirely out of place, for its reserves seldom reach a figure to arrest the attention of the modern engineer, and more often are insignificant. It is only when the records of the production of some of the older camps are studied, which show them to have continuously produced over very extended periods, that a realization is borne home that occasionally this type is worthy of consideration even in these days of gigantic tonnage.

Jan 1, 1925

By J. H. Carpenter

LMENITE, rutile, zircon, and other heavy minerals are found in small amounts in the sand that covers most of Florida. Small enriched deposits occur on the beaches and coastal dunes. One beach deposit east of Jacksonville was worked during World War I and another near Vero Beach during World War 11. Both ceased operation when the resumption of imports reduced prices. Early in World War II reduction of rutile imports made a domestic source of the mineral necessary to maintain the expansion of armaments. Explorations made near Jacksonville discovered a relatively large body of low-grade ore about 10 miles inland from the beaches. A plant installed by Rutile Mining Co. of Florida using both flotation and tables encountered difficulties because of low plant capacity and organic slimes in the ore. In 1944 Humphreys Gold Corp. solved the problem of concentrating the low-grade ore by using the newly developed Humphreys spiral concentrator and by mining with a hydraulic dredge. This combination of low cost mining and concentration permitted the plant to continue operation in competition with foreign ores when imports were resumed following the war. The success of the Jacksonville operation renewed interest in Florida as a source of titanium. An extensive survey of the state was made by E. I. du Pont de Nemours and Co., Inc., under the direction of J. L. Gillson in 1945 to 1946. Sampling was carried on by drive pipe drilling to depths of 20 to 25 ft. Encouraging values were discovered near the location of the present Trail Ridge mine, 50 miles southwest of Jacksonville, near the town of Starke. The United States Bureau of Mines was interested in exploring for heavy minerals in Florida, and on the recommendation of both the state geologist of Florida and of Du Pont geologists, drilled deeper where marginal indications were found on Trail Ridge. In 1947 it was discovered that sufficiently higher values occurred at depth to make the deposit commercial. The orebody at Trail Ridge is a long sand deposit averaging about 1 mile in width and 35 ft in depth. It is approximately 1 1/2 miles wide at the north end of the portion now being worked, tapering to a blunt point 3 miles to the south. The ore reaches a maximum depth of 65 ft near the center and feathers out into barren sand at the edges. The ground surface is relatively flat and is covered with vegetation including pine, scrub oak, palmetto, and occasionally in swampy areas, cypress. The remain of a dense woody growth underlies and marks the bottom of the Ore &apos;One. It is difficult to drill through this layer, but in some cases where it is less than 5 ft thick it has been possible to drive through the wood. Sand lying below is coarser than that in the ore zone and contains no values. The wood layer consists of unconsolidated carbonized fragments of branches and other forest trash associated with a considerable amount of ar-

Jan 1, 1954

By R. O. Neal

There are two main sources of the water that floods productive oil or gas sands. The water may rise from the lower depths of the producing stratum, or it may come from beds above or below the oil-bearing formation. Usually the recovery of oil is decreased by water entering the oil sands, and most oil-field waters, especially those of deep wells, tend to foster the formation of an emulsion, which is expensive to treat. This paper deals with a method of distinguishing between waters that encroach upon oil-bearing beds from sources in the same stratum and waters that reach the oil sands from horizons above. In order to remedy effectually water difficulties in oil and gas wells, it is absolutely necessary to determine the source of the invading water. Sometimes evidence such as the structural relations between the strata penetrated by deighboring wells and those found in the well under investigation is not adequate; also, data from drill logs and well records, from mechanical tests made on the wells by plugs, testers, drilling tools, etc., and from tests by chemical indicators such as eosin and Venetian red, may be unsatisfactory, for such data may fail to locate the source of the infiltrating waters. As a resort in such cases, the application of chemical analyses, that is, the comparison of an analysis of the water in question with that of typical waters from the various water horizons in that particular district, has in certain instances proved of value. This method has been used to advantage in the Westside Coalinga field of California, where the source of water may be fairly definitely determined , from its composition. The chief conclusions concerning the chemistry of the oil-field waters in California by G. S. Rogers1 are: "Oil-field water is not necessarily salty, as is generally believed, and may not be even slightly salty to the taste. The degree of concentration of chloride in such water is governed primarily by local conditions and is not affected by the position of the water in relation to oil. Sulfate diminishes in amount as the

Jan 1, 1920

By W. S. Gillam

A need for new supplies of fresh water exists today and in many specific areas that need is urgent. One solution lies in saline water conversion, a problem complicated by cost factors. The principles involved in saline water conversion, the status of development, and the estimated costs (present and future) of several processes are presented. Among the methods discussed are distillation, electrodialysis, and freezing. In general, the costs presented are based on a standardized procedure for estimating conversion costs, permitting a valid comparison among the various processes. The need for new supplies of fresh water and the potential benefits to be derived from an abundant supply of converted water are recognized by practically everyone concerned with water problems. The water supply problem exists today; it is urgent in many specific areas in this country and also in the world, and it will become more acute in the future. One answer to the growing problem of adequate water supplies is the development of new sources. Very significant quantities of brackish underground and surface waters exist in certain areas and an inexhaustible supply of ocean water is available. Thus in many areas water resources can be extended through saline water conversion. Congress recognized the need for new sources of fresh water in 1952 and passed the Saline Water Act, Public Law 448, amended it in 1955, and in September 1958, enacted Public Law 85-883, calling for the construction of at least five demonstration plants. The program is administered by the Dept. of Interior through the Office of Saline Water, and its primary objective is to reduce the cost of converted water produced, whether it be by development of new processes or improvement of known processes. This is a most difficult problem and one that will require several years of prodigious effort. It is difficult—not because of any intricate or new chemistry, engineering, or physics involved—but because of the difficulty in converting water at low cost. Whatever the sources of the saline water, the salts which are held tenaciously in solution must be removed before the water becomes suitable for industrial or domestic uses. Saline water is a relatively simple system of salts dissolved in water. It has certain chemical and physical properties that determine the various methods by which the salts may be separated from the water. The system, although not complex, in most instances, has had countless years in which to reach equilibrium and is, therefore, comparatively stable. Because of its stability, separation of saline solutions requires relatively large quantities of energy. The unique properties of water depend on the fact that its molecules are chemically active. The chemical and physical properties of water are associated with the type of bonding involved in the water molecule. Chemical changes such as hydrolysis, or rusting of iron, involve the breaking of chemical bonds between the hydrogen and oxygen atoms. Physical changes, such as evaporation in a boiler, the melting of ice, or the viscous resistance to flow in a pipe, involve breaking of the hydrogen bonds. (The hydrogen nucleus is so small that it can attract two negative atoms.) Thus water molecules not only combine with molecules of other compounds but even with one another; e.g., each molecule may be bounded to four other molecules. Water molecules cling to the ions of dissolved salt to form water-encumbered hydrated ions and they cling to one another to form entangling networks through which hydrated ions can be propelled only by tearing the networks apart. That is one reason why considerable energy still needs to be expended in our simplest procedures for purifying water. If water molecules did not have this habit of clinging so tenaciously to other molecules, and to one another, it would be easy to push salt ions past the water molecule and get a separation. But the water would not then dissolve salt, so the problem would not exist.&apos; Water when heated evaporates very slowly, relative to other liquids having simple molecules. Vaporization involves the separation of molecules from the liquid, and this means overcoming the attraction between molecules which is due to the hydrogen bonding. The heat of vaporization for water is high; consequently, the boiling point of water is also high. Water boils at 100" C; hydrogen sulfide (H2S) at -60" C; oxygen (02) at -183" C; nitrogen (N2) at -196" C; and methane (CH4) at-161°C, even though the latter has about the same molecular weight as water. Because of these peculiar properties of water, it exists as a liquid on earth instead of a gas such as hydrogen sulfide or nitrogen and oxygen.

Jan 1, 1961

By Harlod Washburn, Herbert Hoover

This paper is in the nature of a rough preliminary report on the progress that has been made in the application of the mass spectrometer to various problems arising in the petroleum industry. A few years ago the authors considered a number of the problems that were arising in the qualitative and quantitative measurement of small amounts of hydrocarbons. The methods available of making analyses by chemical techniques appeared to leave much room for improvement. Without going into the reasons at this point, attention was turned to the possibility of employing physical instead of chemical methods of accomplishing the desired results. A preliminary investigation disclosed that the mass spectrometer presented a possibility of solving many problems which could not easily be accomplished by other methods. Work was begun in developing the necessary apparatus and technique. A great deal of encouragement and many valuable suggestions were received from Dr. Robert A. Millikan, Dr. W. R. Smythe, and Dr. W. N. Lacey, of the California Institute of Technology, and from Dr. E. 0. Lawrence, who recently received the Nobel Prize, of the University of California. The authors particularly wish to acknowledge the very great willingness of these outstanding scientists to be helpful in solving many of the problems that were involved. So far as the authors are aware, this was the first application of the mass spectrometer to commercial work. The results were considerably better than had at first been anticipated. Briefly, it is possible to run a qualitative and quantitative analysis of an unknown mixture of hydrocarbon gases, with an accuracy of better than plus or minus 5 per cent of each of the various constituents. An exceedingly high degree of sensitivity has been obtained, and a relatively short time is required to complete an analysis. Furthermore, it is unnecessary to separate a mixture of gases into its various components in order to complete the analysis. The Mass Spectrometer The mass spectrometer should not be confused in any way with the optical 01 grating type of spectrograph now in general use. The operation of the mass spectrometer is entirely different in principle and bears practically no resemblance to the optical or grating instruments. The original conception and development of the mass spectrometer dates from and is generally credited to Aston, of Cambridge, England. An early accomplishment of his research, about 20 years ago, was the discovery that the inert gas neon was actually a mixture of two kinds of atoms, one of the atomic weight 20 and the other of atomic weight 22. These two components occurred mixed in such proportion as to yield the usual atomic weight of 20.2. The study was continued and most of the elements were shown to be mixtures of components whose atomic weights can, to in

Jan 1, 1941

By H. B. Pulsifer

ABOUT 15 varieties, or modifications, of the best magnesium available were prepared and subjected to etching tests, then examined for microstructure. Of the 30-odd etching reagents that were tried, nearly half, mostly ammonium salts, etched the metal satisfactorily. The surfacing and etching of magnesium is shown to be a very simple and quick operation. The density and hardness of magnesium were determined. The most interesting new observations relate to the finding of the hexagonal etch figures, the crystal laminations, and the fact that the metal is plastic, cold, when restrained or quickly deformed. Under slowly applied pressure cold metal deforms slightly, then shears to fracture without plastic flow: The chief structural features of magnesium are presented in two reduced photographs and 30 photomicrographs.

Jan 1, 1927