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By W. C. Ellis, E. S. Greiner

Metallic titanium has been prepared in small quantities since the beginning of the century. Hunter1 reported in 1910 that he obtained a malleable product of 99.9 pct purity by the reduction of the tetrachloride by sodium in a closed container. Later Van Arke12 and Fast prepared small quantities of malleable titanium by thermal decomposition of titanium iodide. Another method for producing malleable titanium from tetrachloride was reported by Kr0ll4 who used magnesium as the reducing agent. More recently Dean, Long, Wartman, and Anderson5 working at the U.S. Bureau of Mines have reported the preparation of the metal on a pilot plant scale by the reduction of titanium tetrachloride by magnesium in an atmosphere of helium. Their product, which is malleable, was used in the present investigation. Early in 1948 after the work of this paper was completed Campbell, Jaffee, Blocher, Gurland, and Gonser6 described the strength and working characteristics of pure titanium which was prepared by the iodide method on a scale producing 300 to 600 g per run, in the form of 0.3- to 0.4-in. diam rods. Their product is characterized by low hardness and large capacity for cold work which they attribute to a high degree of purity with respect to oxygen, nitrogen, and carbon. Titanium has a melting point of about 1725 C," it may be classed as a light metal since the specific gravity is 4.5 g per cc-I. The crystal structure is close-packed hexagonal from room temperature to 885°C. Above this temperature the structure is reported7 as body-centered cubic. The change in crystal structure has been associated with discontinuities in specific heat,8 electric resistanceg and theimoelec-tric force10 at temperatures near 890°C. It is reportedll that annealed titanium has a tensile strength of 78,700 psi which can be increased by cold-work to 123,000 psi. In the present investigation, the lattice constants at room temperature, the thermal expansivity between 30 and 800°C, as well as the electrical resistivity and thermoelectric force against platinum between — zoo and I000 C have been determined. Materials For the measurements, two series of specimens were prepared from titanium furnished by the U. S. Bureau of Mines. The first was made from an annealed sintered compact, 0.38 in. thick. Sections of the compact were cold-swaged with intermediate anneals in vacuum to the sizes used. Sizes over 0.25-in. diam were annealed at I000°C and smaller sizes at 800°C. Specimens originating from the sintered compact are designated in this paper as A. The second series of specimens was made from a rod of titanium, 0.19 in. in diam, which was cold-swaged with the necessary intermediate anneals to the required sizes. This series of specimens is designated B. The impurities in the specimens of titanium, determined by chemical analysis, are given in Table 1. Oxygen and nitrogen which Were not determined by analysis, are probably present although in small quantities in view of the ductility of the material.

Jan 1, 1949

By M. S. Burton, J. E. Ritter

The sessile-drop technique was employed to study the effect of atmosphere and alloy additions of titanium and chromium on the surface tension and contact angle of nickel on sapphire substrates at 1500oC. Shear tests were conducted on the solidified sessile drops. The liquid-gas surface tension of pure nickel on sapphire was found to be 1747 ergs per sq cm, with a contact angle of 109.6 deg. The surface tension and contact angle were not affected significantly by the four atmospheres, vacuum, impure argon, pure argon, and pure hydrogen. Small additions of titanium and chromium decreased the contact angle and for the same alloy content, contact angles were lower in pure argon than in pure hydrogen. On the basis of shear-test results , the most probable cause for adhesion in the Ni-Al2O system is the formation of NiO:Al2O3 spinel at the interface; in the titanium alloy-Al2O3 system adhesion is thought to be due to a mechanical interlocking effect; in the chromium alloy-Al2O3 system adhesion is believed to be the result of solid-solution formation involving Cr2O3 and Al2O3 at the interface. In the last few years there has been considerable interest in reinforcing metals with ceramic whiskers. It has been postulated that, by reinforcing nickel with sapphire whiskers, high-temperature strengths su- perior to those of the best current nickel alloys can be achieved.' To fabricate a whisker-metal composite having optimum density and strength, understanding of wettability and adherence in the system is of prime importance. Although there has been some previous research in this a a need for further studies has been cited4-8 to understand better the effects of impurities, alloys additions, and atmosphere on the wetting and bonding of metals to metal oxides. The purpose of this research was to investigate the factors involved in the wetting and adherence of nickel/nickel alloys to sapphire (single-crystal a Al2O3). Sessile-drop experiments were conducted in vacuum, impure argon, pure argon, and pure hydrogen, to determine the effect of atmosphere on the contact angle of the metals on sapphire, and the liquid-gas surface tension of pure nickel. The solidified sessile drops were sheared from the sapphire substrate to measure the bond strength between the metal and ceramic. The alloy additions chosen were titanium and chromium since both enhance the wetting of nickel on sapphire.2, 3c Also, titanium is commonly used when brazing metal-to-ceramic seals to improve adherence. Since chromium forms an oxide that is completely soluble in sapphire, it was thought that the oxide could serve as a transition phase to promote bonding between the Ni-Cr alloy and sapphire. I) EXPERIMENTAL APPARATUS AND PROCEDURE The sessile-drop apparatus was a horizontal furnace, with an induction-heated, cylindrical molybdenum susceptor in a water-cooled Pyrex chamber. This apparatus was patterned after that of Williams and Nielsen.7 A flat Pyrex window at each end of the furnace allowed temperature measurements to be made at one

Jan 1, 1968

By Jeff Steinhoff

INTRODUCTION The Henderson mine utilizes a highly mechanized, continuous, panel-caving, mining system to extract ore from a deep, massive, molybdenite deposit. The mine is located 80.5 km (50 miles) west of Denver, Colorado. The mine surface facilities are located 3,170 m (10,400 feet) above sea level in a steep valley on the eastern side of the Continental Divide. Milling facilities are 24 km (15 miles) west on the western side of the divide at an elevation of 2,804 m (9,200 feet) above sea level. The ore- body is located approximately 3,000 feet south of the valley under Red Mountain. Access to the ore for men and materials is through a 915 m (3,000-foot) deep, 8.5 m (28-foot) diameter, vertical, concrete-lined, service shaft. Access from the mill is through a 15.5 km (9.6-mile) rail haulage tunnel. The mine is ventilated through an additional intake shaft and two exhaust shafts. Mine production at this time is 27,255 mtpd (30,000 stpd). The mine ventilation system supplies 1,038 cubic meters per second (2.2 million cfm) through approximately 60 miles of drifting or 2.7 tons of air per ton of ore mined. There are 130 fans in the mine in fixed locations and in vent lines with 6,900 connected horsepower in the mine. MINING METHOD AND LAYOUT The orebody is divided vertically into two major zones. The upper zone is the 8100-level production area. The bottom zone is the 7700- level production area which is in the early development stage. The rail haulage level at 7500 feet is common to both production zones. Each mine production zone consists of five associated sublevels. The cave undercut level is 16.8 m (55 feet) above the production level. Two boundary cutoff levels are located 44.2 m (145 feet) and 62.5 m (205 feet) respectively above the production level. The fresh-air level is positioned 15.2 m (50 feet) below the production level, and the exhaust vent level is 19.8 m (65 feet) below the production level. Horizontally, each production zone is divided into three panels each, 224 m (800 feet) wide. These panels are caved from south to north. As the caving in one panel nears completion, caving in the adjacent panel is initiated. Development for the caving panels is continuous so that the sublevels above the production level and the production level itself have a combination of development drifting and production-related activities. UNDERGROUND VENTILATION NETWORK The ventilation system is zoned in the same manner as the orebody itself. One major split of 600 cubic meters per second (1,270,000 cfm) ventilates the 8100-level production zone; one split of 100 cubic meters per second (210,000 cfm) ventilates the development of the 7700- level production zone; and one split of 165 cubic meters per second (350,000 cfm) ventilates the 7500 rail haulage level. The haulage tunnel requires an additional 188 cubic meters per second (400,000 cfm) of air. Development-drift ventilation is accomplished by hanging 1.0 m (3.5-foot) diameter steel ducting in the drifts with 40-horsepower, 0.96 m (38-inch) diameter fans supplying 9.4 cubic meters per second (20.000 cfm). The normal maximum length for these systems is 300 m (1,000 feet). The 8100-level production-area ventilation system is especially suited to a high level of mucking activity confined in a small area. Approximately 93 per cent of the mine's total production is transferred from the drawpoints to ore passes in 10 production drifts. The active area in each drift is 300 m (1,000 feet). Twelve 5-cubic-yard LHD units with Cat turbo- charged 170-horsepower engines are assigned to the area. Under these conditions, more than one LHD is assigned to a particular production drift. Adequate ventilation is maintained by making an air change every 97 m (320 feet) along the production drifts. Fresh air is brought into the production drifts from the fresh-air level through 1.37 m (4.5-foot) diameter raises. Air travels south along the production drift to the ore pass where it is exhausted down the ore pass to the exhaust level. The ore pass is followed by another intake which is followed by an ore-pass exhaust. At the south end of the production area, a series of exhaust fans maintain a southerly air- flow through the production level.

Jan 1, 1981

By Rossiter TV. RAYMOND, Charles H. Snow, THEODORE DWIGHT

SECRETARY'S NOTE.-The complete list of all officers of the Institute will be found on p. iv. of this number of the Bulletin. The following explanation may recall to old members, and convey to new ones, the relations of the two governing bodies, as determined by the, Certificate of Incorporation of the Institute, and the Constitution and By-Laws adopted in accordance therewith. The body legally responsible for the business management is the Board of nine Directors (three elected annually to serve three years), which elects its own officers. This body, for reasons of practical convenience, is composed of well-known members, residing in New York City, and able to attend, without serious inconvenience or expense, the necessary meetings of the Board. The officers of this Board are legally the officers of the Institute. But, apart from business manage-ment, the Board exercises no control over the election of members, or the professional and technical work of the Institute, except that its vote is required to elect honorary members, upon the recommendation of the Council. The Council is a. body, constituted in all respects (except that it has no Treasurer) like the Council existing before the incorporation of the Institute, in January, 1905, and charged with all duties and powers, except those which the Board of Directors must legally perform. It elects members, appoints the times and places of professional meetings, and controls the publication and distribution of papers and volumes, etc. Its members (President, Vice-Presidents and Councilors) are elected by the members of the Institute, voting in person or by proxy, and after publication of the nominations received ; and it is intended to repre¬sent, as far as practicable, both the professional and the geographical distribution of the membership. Consequently, whatever professional honor attaches to official position belongs to membership in the Council, rather than in the legal Board of Directors. This remark implies no disparagement of the members of the latter body, every one of whom has served, or is now serving, as a member of the Council. But it is only fair to explain that their election and continued re-election as Directors is simply a matter of legal convenience.

Mar 1, 1906

Mr. Brown : .That part of the Standard Company's plant which has been added since the publication of Mr. Leggett's paper, and is described in mine, renders the single-phase, alternating system, which Mr. Hale has called " unelastic," much more elastic than it had been. The original plant at Bodie was substantially the same as the Telluride plant mentioned in his paper. The machines came from the same shops, and were practically the same; but while the Telluride Company has changed completely to a polyphase system, the Standard Company has retained its original plant, but has belted on a directcurrent generator at the receiving end, thereby converting the water-power into electricity, electricity into power, the power into electricity, and finally again electricity into power for use in the mines. This is a roundabout course, to be sure, but it shows that there are possibilities even in the out-of-date single-phase system. The only point perhaps, that deserves particular notice with respect to the hoist is the fact that the rheostat, or starting-resistance, was not built originally

Jan 1, 1897

By William Copp

THE SEAL BEACH oil field is between the Long Beach and Huntington Beach oil fields, south of Los Angeles, and about half the productive area is with-in the city limits of Long Beach. The proved area lies in portions of Sections 2, 3 and 11, T. 5 S., R. 12 W., S. B. B. & M. Seal Beach is 'an additional link in that remarkable chain, of oil fields extending from Newport to Beverly . Hills, filling in one of the few remaining gaps. It differs from other fields along this line of folding in that it is an oil field in an area of tide lands. Ocean-connected sloughs have access to this area, which ac-counts for its extensive mud flats. The surface eleva-tion of the low ground varies from 2 to 5 ft. above sea-level. This condition called for much preliminary work in building roads prior to field development. Roads are constructed with dredges and drag-line scrapers, which excavate mud from alongside the proposed road and pile it up to a grade high enough to be above high tide. The road bed is then surfaced with gravel, or decom-posed granite, which makes it serviceable in all kinds of weather. An immense amount of road material has already been hauled into this field. Well locations are staked in the mud flats, sometimes ahead of road build-ing, and material is dragged to its place on the ground by tractor. It is necessary to drive piling to support derrick foundations. The present practice is to drive 5 piles for each derrick leg, 4 under the rotary table, 2 under the draw-works, 2 under the Samson post and 4 under the pipe rack, a total of 32 piles. This pro-cedure is, of course, varied to suit special conditions, using either more or less piling.

Jan 6, 1927

By Macelwane

WHAT characterizes a geophysical engineer and sets him apart from all other engineers? This is a question that is important not only for accrediting purposes but is assuming increasing importance in the licensing of professional geophysical engineers by state boards. What is the basis of distinction of one type of professional engineer from another type is answered in part by the need which brought each type into being precisely because that need could not be satisfied by pre-existing types and which nevertheless demanded the special outlook, training, and abilities of an engineer. The need which called for the civil engineer was the adaptation to the tasks of civilian life of the capabilities developed by the military engineer for the design and construction of roads, bridges, dams, earthworks, military buildings, and other structures and of mechanisms required by military operations.

Jan 4, 1954

By A. Blake Caldwell

Northwest frontier is here defined as Alaska, the Yukon, the Northwest Territories and northern British Columbia. The mineral potential of this area is great and will unfold in the decade ahead but now the largest single producer is the Pine Point lead-zinc mine in the NWT about 1200 km north of Edmonton, Alta., close to the south shore of Great Slave Lake. The mill, initially designed for 4540 mtpd, was expanded to 7250 mtpd in 1969. This operation is described in detail in Mining and Concentrating of Lead and Zinc, Vol.1, Chapt. 17, SME/AIME in the article by W. H. R. Gibney.

Jan 1, 1971

By B. R. Queneau

Steel has been chosen as the metal whose solidification will be used to tie in the principles discussed in the previous papers. Although steel is the most important [ ] practical example that could be chosen, its solidification is complicated by the presence of many elements added either intentionally or present as impurities. The liquid steel bath in an open-hearth furnace contains carbon, manganese, phosphorus, sulphur, and many residual alloying elements such as nickel, copper, and molybdenum. The bath also contains oxygen, the concentration of which is a function of the carbon content, as shown in Fig. I. Deoxidizers such as silicon and aluminum may be added either before or after tapping depending on the grade of steel being made. There are four types of steel ingots: Killed, semikilled, capped, and rimmed, and these differ from each other in their state of oxidation. Each type of steel has advantages in the production of specific steel products, and it should be emphasized that no one type should be considered superior to the others. Fully deoxidized steels, known as killed steels, have little or no gas evolution on solidification. When the steel solidifies in the mold, shrinkage occurs which causes a large void known as "pipe." To minimize the amount of metal that has to be discarded on account of pipe, a big-end-up mold is used together with a refractory "hot top" which supplies molten steel to the main body of the ingot while solidification proceeds, Fig. 2. A section through a 32x32 in. ingot is shown in Fig. 3. The "hot top" volume is about 15 pct of the ingot, and the yield from killed steel in billet form is about 8o pct of the ingot weight. High quality machinery and tool steels are rolled from killed-steel ingots, but at the present time this represents less than 20 pct of the total steel production in the United States. In order to reduce cost and to increase

Jan 1, 1951

By Chester B. White

ARGENTINA is a country that has never been properly prospected. This is my settled conclusion after reporting on mines in this country ever since 1914, crossing all the mining provinces from Chubut, in the South, to the territory of Los Andes, in the North, chiefly on muleback. It is difficult and costly to get from one district to another. Apart from petroleum, some mineral discoveries have been made but they have been the result of casual rather than systematic work. In Neuquen, Mendoza, San Juan, Cordoba, La Rioja, Catamarca, and Los Andes attempts at mine development have resulted in failures, involving in each instance several million pesos.

Jan 1, 1937

By B. H. Dunshee

THIS paper is not intended to be a technical discussion of square-set framing as used in mines, but merely a short description of the different kinds of framing that have been used in the Butte mines, and what has been decided upon, after years of practical experience, as being the best, taking into consideration the physical condition of the veins and country rock, and. also the supply of timber available for mining purposes. Butte is, essentially, a square-set district. Virginia City, Nev., was the first mining camp to use this method of timbering, and to Philip Deidesheimer, who went to the Ophir mine in 1860, is given the credit of solving the problem of square-set framing, where large bodies of ore were stoped and the timbers were supposed to hold the ground from caving without any filling. That he did his work well is shown by the fact that the main features of his framing are in use to-day. In the Butte mines the conditions are such that this method of timbering is generally used. We do not, of course, depend upon the timbers any more than is necessary. The worked-out stopes are filled with waste rock as close behind the miners as possible and not interfere with mining operations. The waste rock is obtained from development work on the different levels or from the surface. In the earlier days of mining in Butte there were numerous independent companies and naturally there were different ideas as to the best way to frame the square sets, although the general features were the same.

Jan 8, 1913

By V. D. Perry

AS the traveler approaches Chuquicamata from the seaport of Antofagasta, crossing in a northeasterly direction the 150 miles of coast range and completely barren pampa with its low, rolling hills and broad depressions, the gradual rise to an elevation of 9000 ft is imperceptible, and it is hard to realize that the smoothly contoured hills east and west of the mine are from 10,000 to 11,000 ft above the level of the sea. The deceptive monotony of the scene is relieved only by the background of an unbroken line of lofty volcanic peaks, part of the Andean Cordillera, which rise, snow covered, against the eastern skyline. The drab geographical foreground is matched by the geological monotony of unaltered, gray rock

Jan 1, 1952

The first mention of the occurrence of native copper near Lake Superior is found in a book by Lagarde, published in 1636. The letters of the Jesuit missionaries in the seventeenth century refer to the use of this copper by the Indians. Francesco Bressani, an Italian friar, says, in 1653: "There is a copper ore, which is very pure, and which has no need of passing through the fire; but it is in places far distant and hard to reach. We have seen it in the hands of the barbarians".* Father Jerome Lalemant, writing in 1659, says that the coast of Lake Superior is "enriched with copper of such excellence that pieces as large as one's fist are found, all refined.† These pieces of copper were hoarded by the Indians as mascots. The mention of the metal as having been already refined by nature recalls the fact that the old Greek historians spoke of gold-dust as being apuron, or not needing the fire. Father Claude Allouez,‡ writing in 1666, says: "One often finds at the bottom of the water [of Lake Superior] pieces of pure copper, of ten and twenty livres [pounds] weight. I have several times seen such pieces in the savages' hands; and since they are superstitious [as if the padres themselves were not!], they- keep them as so many divinities, or as presents which the gods dwelling beneath the water have given them, and on which their welfare is to depend. For this reason they preserve these pieces of copper, wrapped up, among their most precious possessions".

Jan 1, 1932

By George Smith

IN discussing present-day business and industrial troubles we easily drop into the habit of clinical diagnosis. Talk of this kind, with its emphasis on suspicious symptoms and abnormal tendencies, makes us all morbid. As an English essayist has put it, we may thus induce a melancholy, temper that simply in-vites the ministrations of social and political quacks. It is far better-because nearer the truth-for us to recognize that our condition is in no sense diseased, that our body politic, social and economic, is suffering merely from growing pains; that America is not de-cadent-indeed, that any lapses from staid normality are traceable to the, excesses of youth. Our chief .trouble, then, is only that our industrial state is still young; it may be that we have been growing too fast. The growth in the industrial development of our country from pioneer days to the present time has been marvelous. Too many of us, however, take all this as a matter of course-we credit this record of American progress to our American genius alone. Too often we overlook the fundamental relationship between resources and progress-that man is aided and even guided by Nature. The fact is, social advance, indus-trial progress, national prosperity all have their ma-terial basis in natural resources. In furnishing the needed mineral raw materials to the great manufac-turing industries of the United States there has been no halt, but rather a general acceleration. No other phase of American activity can show-equal advance. As the decades have passed, the winning of mineral wealth has progressed from the role of a stimulus for western exploration to that of the foundation for nation-wide business. In 1890 the Sherman law was passed; since then the population of the United States has about doubled. Since then, too, thevalue of the annual product of the mines of this country has increased better than eight-fold-from 650 millions to 51/ billions of dollars. Since then the four largest branches of the mineral industry, which supply the iron and copper, the bituminous coal and petroleum-the bone and sinew and the energy of all other American industries-have increased their annual output nearly ten-fold as to value and six-fold as to quantity. Such a growth in the volume of mineral output must be taken as a true measure of the ex-ceptional service rendered by the mines of the United States. Not only is this a much larger country than it was 38 years ago, but its growing mineral industry has met demands that have been out of all proportion to the growth of the population.

Jan 8, 1928

By Chester Washburne

AT present it is impossible to estimate closely the amount of oil obtainable from a given area of land. However, after the completion of a few properly distributed prospect wells, one can calculate the approximate yield of the sands penetrated, with a probable error of say 50 per cent. Even rough predictions of this kind are of value in, large operations. Without wells upon it, one can never be absolutely certain that an area will produce any oil whatever, and one can only indulge in wild guesses of the probable productive area, before the geological structure has been carefully contoured and the top of the basal water plotted on a map. This requires wells. At times it is desirable to form an idea of the possible yield of oil in advance of drilling, as in cases where the price asked for undeveloped land seems too high, but where the probability of finding oil is furnished by neighboring development, supported by the geology. In such cases the most one can do is to make an estimate of possible maximum yield, which may of course far exceed results, and which is of use mainly in the prevention of excessive initial investment. The method is very significant in a general way, as in regions like the Bighorn Basin, Wyoming, where the productive sands in the Cretaceous shale are so few and so thin and fine that they cannot develop very great production, although the high quality of the oil probably will counterbalance this defect sufficiently to give local profit in favorable areas. Reservoir Capacity of Sands.-The porosity of a stratum is the measure of its maximum reservoir capacity for liquids and gases. The porosity may be determined experimentally and must be used in connection with the total volume of the sand.

Jan 2, 1915

By Dr. O’Neil Thomas J., Donald W. Gentry

Money is like an arm or leg-use it or lose it." -Henry Ford INTRODUCTION If it were not for the existence of interest, the analysis of investment opportunities would be greatly simplified. In the absence of interest, investors would be indifferent as to when cash outlays are made or cash benefits are received. It would, in fact, be irrelevant whether the outlays preceded or followed inflows as long as both amounts are known with certainty. Of course, it does make a considerable difference whether, for example, a firm receives $1 million now or five years from now. The reason is that money does, indeed, have a value which is a function of time. Interest is how this time value is measured. Interest is generally defined as money paid for the use of borrowed money. In other words, interest is the rental charge for using an asset over some specific time period. The rate of interest is the ratio of the interest chargeable at the end of a specific period of time to the money owed, or borrowed, at the beginning of that period. In order to understand why interest exists, it is necessary to take the lender's viewpoint. The lender can justify charging interest for several reasons: 1) Risk: The lender is faced with the possibility that the borrower will be unable to repay the loan. 2) Inflation: Money repaid in the future will be in units of lower value due to inflation. 3) Transactions Cost: There will be expense incurred in preparing the loan agreement, recording payments, collecting the loan, and other administrative tasks. 4) Opportunity Cost: By committing limited funds to one borrower, a lender is unable to take advantage of other available opportunities. 5) Postponement of Pleasure: By lending money, an individual (or organization) is postponing the pleasure which that money could purchase. Each of these is a valid reason for a lender demanding interest from a borrower. The level of interest is, like the price of other assets, determined by supply and demand. Nonetheless, from time to time various analysts have taken a then current average interest rate and broken it down into the components described previously.

Jan 1, 1984

By Charles S. Barrett

THIS paper is a progress report covering metallographic applications of the electron microscope that have been made during the past year at Carnegie Institute of Technology. An account is presented of the techniques that have been most satisfactory, the difficulties encountered, the resolution obtained, and the peculiarities that have been noted in the microstructures. About 12m exposures have been made during the year on the instrument, which is an RCA type B2 transmission microscope,1 and a number of these have been selected to illustrate the results obtained. Prints are also included showing the common types of falsities-to borrow a term from the biological field, the "artifacts." In brief, the paper is a record of our attempt to determine the value of the electron microscope in the study of the structure of metals and alloys. n addition to comments on techniques and the quality of photomicrographs obtainable with them, the paper discusses the nature of the etch attack on a few metals, and the possible relation between the fine structure revealed by etching and the mosaic block structure of the grains. Since numerous papers and reviews are available on the subject of imperfection in crystals, the comments here may be very brief; in fact, are restricted almost entirely to points having to do with recent theories relating the strength of metals to imperfections and to spacings of slip lines. SPECIMEN PREPARATION AND PHOTOGRAPHS Mechanical polishing by hand was used throughout this work. Precautions that must be taken in microscopy at high magnification, which have been well explained by Vilella in his book on Metallographic Technique for Steel, are likewise important with the electron microscope. This applies particularly to the need for repeated polishing and etching (each successive polish becoming less severe and each etch lighter), since the final etch should in general be no heavier than is used for oil-immersion optical microscopy and in many instances should be much lighter (compare Figs. 6a and 7a, 6d and 7b). An extremely light etch, of course, is incapable of cutting through a flowed layer of appreciable thickness. Unquestionably it would be very advantageous in each instance to compare the structures obtained by electrolytic polishing with those obtained by mechanical polishing, but difficulties with the electrolytic method have prevented this in the following collection of prints. The choice of etchant is important, of course; for example, picral proved superior to nital for tempered martensite. With the exception of Figs. Ib and IC, the replicas used were of silica, deposited up0n polystyrene and floated from the polystyrene in ethyl bromide according to polystyrene in ethyl bromide according to the method of Heidenreich and Peck.2 The samples were mounted in Bakelite, polished and etched, then the polished Bakelite

Jan 1, 1943

By F. F. Sharpless

IT IS to be. read in Western newspapers that Hon. S. S. Arentz who introduced H. R. 7736, 'has repudiated it, that certain mining men in Utah and Nevada say that they will fight it "until hell freezes over." It is to be read in more temperate expressions that "the eminent engineers who drafted the bill exhibited a woeful misunderstanding of Western sentiment and opinion." Furthermore, it is averred that there is no need for revising the mining laws, that we have got along pretty well under the existing laws, etc. Such statements are so surprising in view of, the facts of record that it is hard to believe that the oppon-ents of the bill, who make them, are well informed, or that they represent general opinion. It will be useful therefore to review the record of the case. Our GOOD OLD MINING LAWS We have indeed got on well in our mining industry, but that has not been by virtue; of our good old mining laws. Rather has it been in spite of them. Ever since the Richmond-Eureka case in the '70s there has been litigation arising from them. Early in the '80s the apex law was discarded by common consent in Leadville, and it has been ignored in every district of flat-lying ore deposits ever since. The great mines of the present time are the porphyry copper deposits. At Bingham, Ely, Ray, Chino, Miami, Clifton and Ajo the apex law is simply inapplicable. A law that is inapplicable to the modern conditions of mining may be an old law, but it can not properly be characterized as a "good" law. For such reasons, and many others of weight, there has been a demand for revision of the mining laws; dat-ing ,back at least three decades. President Roosevelt appointed a commission to advise respecting the question, said commission comprising. Dr. James Douglas (chairman), John Hays Hammond, D: M. Barringer, Walter B: Devereux, and William B. Mather. This committee was unanimous on the following points:

Jan 1, 1922

By John H. Hollomon

IN a recent paper,1 a very early suggestion by Ludwik2 concerning the nature of the mechanical behavior of metals has been reexamined and extended. In essence it was [ ] suggested that there exists, at least under certain conditions, a mechanical equation of state; that the stress required for flow depends upon the instantaneous values of the strain, strain rate, and temperature, and not upon their past values. It is proposed that under these circumstances the stress does not depend upon past history of these variables, but is like the temperature of a gas that depends only upon the I instantaneous values of the pressure and volume. This notion has not been applied to present day studies of metals, though it is especially applicable to the study of creep. It is the purpose of this paper to analyze the significance and possible range [ ] of applicability of this idea and to deter- mine how it influences the accepted ideas concerning creep. STRESS-STRAIN RELATIONS It is well known that the stress-strain curves of metals are influenced by both strain rate and temperature. For a fixed strain rate and temperature there is associated with each metal a stress-strain curve. If either the strain rate or temperature is changed a new stress-strain curve will be characteristic (Fig. I). A much more general relation between the effects of the sevariables is possible, however. Consider the stress-strain curves of Fig. I determined at

Jan 1, 1946

By H. J. Ward

RUM Jungle uranium field lies in the subtropical portion of the Northern Territory on the Finniss River, East Branch. It takes its name from a railway siding about 2 ½ miles to the southwest and 52 miles from Darwin. The field can be reached from Darwin by a bituminized road. Monsoonal rains of the wet season, October to April, provide an annual rainfall of about 60 in. Vegetation is of the open forest type with denser tree growth along the watercourses and scattered throughout the area are isolated dense patches of jungle growth which are always found on ironstone cappings overlying limestones. The name, Rum Jungle, is thought to have been derived from this unusual occurrence of jungle growth. The wet season prevents the movement of motor vehicles and personnel. It is not until March, when the grass which ranges up to 15 ft in height is burned and the alluvial flats dry out, that field work can be undertaken.

Jan 12, 1954