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By W. H. Meyer

During the seventeen years Fairchild has been making aerial surveys and aerial photographic equipment many changes and improvements have been made in the equipment and in the technique of using it. Aerial photographic operations have been developed from the crude methods and apparatus of wartime to a science upon which exact engineering calculations can be based. In the early days there was no airplane specially designed to meet aerial photographic requirements. One type of camera was used in all types of operations. Projects were made to conform to the products we could make and deliver. Obviously this entailed definite limitations. We now have airplanes designed specially for aerial photographic operations in accordance with the conditions encountered in actual service experience. We have cameras for every photographic purpose and our laboratory technique and equipment have been developed to the point where it is possible to make contour maps from vertical aerial photographs with contour intervals as close as five feet. Therefore, the selection of equipment now can be made in accordance with the time at our disposal, the justifiable cost, the scale desired, and the general requirements of the client. This does not mean, however, that arbitrary deliveries can be set for aerial photographic products. The factors in each project vary and each job must be considered in accordance with the factors involved. This accounts for the fact that products of aerial surveys may readily vary from $1.25 to $200 a square mile. Sherman M. Fairchild became interested in the design of a radically different aerial camera during the war. At its close he was about ready to demonstrate his design to the War Department. By 1920, he was able to bring out his first completed model. It had a number of radical features, one of which was the first dependable high-speed between-the-lens shutter, which makes for accuracy in aerial photographic work. Another feature was the use of metal throughout, eliminating the wooden parts that had been employed in wartime cameras. Another feature was the interchangeability of parts.

Jan 1, 1937

D. M. Riordan has been appointed a member of the Institute Com¬mittee of the Engineers' Reserve Corps movement. Our Committee, therefore, now consists of Henry S. Drinker, Chairman, Messrs. Arthur S. Dwight, Warren A. Wilbur and D. M. Riordan.

Jan 1, 1916

By C. B. Post, D. G. Schoffstall

A determinatioil of the hydrogen content of molten steel by means of the Vacuum-extraction method, as reported here, consists in first casting a sample of the bath in a bomb, so that the gases evolved during solidification are trapped for analysis. A portion of the cast steel sample is then prepared and heated at a temperature of 600" to 800°C. under high vacuum, and the gaser given off during this vacuum extraction (which are shown to be hydrogen), are collected and measured. Analysis of the gases evolved on solidification and the gases in the solid sample enables an accurate determination of hydrogen in the molten steel. Fig. I shows the bomb and accessories that have been found suitable for trapping the gases evolved on solidification. The bomb is made of scamless steel pipe, approximately 7 in. long by 136 in. i.d., and welded at the bottom. An ordinary pipe cap has a vacuuni-type metal stopcock threaded and brazed in its upper end. This pipe cap fits onto the bomb by means of machined threads. A flange is brazed to the pipe at the point where the cap starts to tighten up, and a rubber gasket is placed between the flange and cap. Heavy vacuum grease is used between the flange and gasket and the gasket and cap. The weight of the complete bomb and it? interval volume is known before the sample is cast. In practice, a sample of about 400 grams of steel is poured into the bomb, the funnel quickly swung out of the way, the bomb cap spun down the threads and tightened against the gasket, and the bomb set in a pail of water to keep the gasket and vacuum grease cool. It is estimated that at least 80 per cent 01 the gases evolved from the liquid sample during solidification are trapped in the bomb."

Jan 1, 1945

By Charles Hart

THE-report of the advisory committee to the U. S. Bureau of Mines, on the use of oxygen in metallurgy, brings to the art of steelmaking a radical change in the method of operation of the many processes of this widely diversified industry. When completed, the improvements suggested by the use of oxygen will be far-reaching and revolutionary. As to its effect upon the iron blast furnace, the use of oxygen should be as important as any of the improvements in the art of iron smelting and should take its place beside the German "Hochofen" which was the first attempt to use a shaft for preheating the stock, and beside the hot-blast stove which heated the blast before entering the furnace. The former initially produced molten iron and the latter made unbelievable economies in fuel consumption. It would seem that a discussion of this paper would be best served by following the conclusions on page 17 of the report and analyzing them seriatim. 1. (a) A decrease in costs, due to higher smelting heats is only attainable by taking full advantage of these heat units. This is affected by, adding additional ore to the burden which in turn increases production and yields a larger tonnage upon which to figure costs. These economies appear in decreased cost per ton of iron for coke and limestone consumed, and a proportionate reduction in all items entering the cost above materials. We can take no exception to these. premises. It is a well-known fact that silicon in the iron and sulfur removed" are the result of hearth temperature, other matters remaining constant. To a practical furnaceman the most satisfactory manner of controlling a furnace is by increasing the burden. It is not necessary, therefore, to consider the question of refractories, for this discussion presupposes that the temperatures in the furnaces will be kept practically where they now stand for making the various grades of iron. The same situation obtains in regard to the height of the furnace, which, as intimated, was one of the great strides forward in this art, and its abandonment at this time, is inconceivable. The shaft prepares the stock so that at each succeeding step we have exactly the proper conditions. All the stock entering the furnace is dried and preheated. The limestone is calcined by sensible heat practically at no cost, for this is sensible heat which otherwise would pass from the top with the gases. Under normal conditions, external calcination has been attempted without tangible results. Under normal average furnace operation, limestone requires about 760 B.t.u. for calcination and the loss of sensible

Jan 11, 1924

By Stephen Krickovic

AS it is commonly understood in the bituminous coal mining industry, pillaring means removal, as completely as is practical, of all pillars formed in the development of headings and rooms on first mining. The degree to which this can be accomplished, termed percent of recovery, is of course dependent generally upon the physical conditions of the bottom and the overburden, the system of min-

Jan 1, 1956

By J. L. Lamon, W. Crafts

P. Coheur and L. Habraken—We read this paper with great interest and are glad to congratulate the authors for their valuable work, supplying an important contribution to the mechanism of tempering on the carbides in vanadium steels. We are in a good position to appreciate this work since we have been studying, for more than a year, Cr-Mo steels of a composition similar, but less highly alloyed (namely 0.1 pct C, 3 pct Cr, 1 pct Mo). Our results are quite in concordance with the authors', however, we wish to point out that it is very interesting to use equally the electron microscope in order to observe the variations of microstructure in steels. We have studied simultaneouslv the evolution of the carbides in situ with the electron microscope, and, after extraction, again with the electron microscope, and then with X-rays. The first results which we have obtained have been communicated at the Congress of Delft (July 1949) and at the "Journbes de la Metallurgie" in Paris (October 1949). These may be summarized as follows: After tempering with varying either the tempering temperatures or the tempering times, the carbides show two evolutions. The first one is connected to the carbides existing in the steels, principally in the boundaries of the grains. For some groups of steels these carbides may coalesce and for other groups they may

Jan 1, 1951

Jan 1, 1888

By Tadeusz Cyrul

Results of a large scale compression test in situ are the subject of discussion. A cube of coal having an edge length of 1.5 meters was subjected to uniaxial compression tests in situ. At the same time both load and deformation were controlled. Deformations were measured on 60 short measurement bases, each 23 cm in length. The bases were uniformly distributed on the side surface of the cube, forming five horizontal rows and twelve columns on the development of the surface. Readings were taken from each gauge for each level of loading which was increased step by step. Due to heterogeneity of the rock, readings showed scatter. Scattered data were approximated by a plane, using the least squares method for each row separately and for the entire population of bases. Orientation of the planes are analyzed. The geometrical measure of the bending moment is introduced. It shows that the magnitude of the bending moment and the bending plane differed from row to row, thus implying that the cube was not only bent but twisted as well. This complex behaviour of the coal cube is apparently caused by its heterogeneity and vertical anisotropy. The results constitute a contribution to the verification of existing design criteria on the stability of mining pillars.

Jan 1, 1984

The following Nominating Committee having been already appointed and approved by the Executive Committee in accordance with authority vested in the Executive Committee by the Board of Directors, was approved by the Directors: John V. N. Dorr, Chairman, Percy G. Beckett, J. W. Hutchinson, Julian Kennedy, William H. Linney, Charles W. Merrill, and E. Gybbon Spilsbury. The question of the purchase of Liberty Bonds, as well as that of bringing to the attention of the members the advisability of the purchase of these bonds, was referred to the Finance Committee. Sixty Members, four Associates, and thirty-six Junior Members were elected. Two Members were reinstated. Eight resignations were accepted.

Jan 7, 1917

By R. V. Wheeler

A MATTER of much concern at present to the coal-mining industry of-Great Britain is the effect of the working of the Coal Mines Act, 1930. This Act, which received the Royal Assent on Aug. 1, 1930, contains five parts: (I) production, supply and sale of coal; (II) the reorganization of the coal-mining industry; (III) hours of work; (IV) the Coal Mines National Industrial Board; (V) general. The first three parts are of major interest and discussion can be confined to them.

Jan 1, 1931

By Smith Bracewell

First evidence of bauxite in Jamaica resulted from an analysis of a soil sample collected at Bull Savannah in 1938 during a systematic local investigation of the island's soil types. Results of subsequent work indicated the possibility of the occurrence of deposits of commercial grade and dimensions, and in 1942, with a view to emergency development of the deposits as a war measure, the Jamaican Government declared all bauxite in the colony to be Crown property.

Jan 10, 1958

Executive JVW REYNOLDS, Chairman SYDNEY H BALL E DEGOLYER WILLIAM H BASSETT SAMUEL A TAYLOR Finance GEORGE D BARRON, Chairman H A GUESS GEORGE OTIS SMITH Membership ] H CALLOW, Chairman GEORGE D BARRON WILBER JUDSON JOHN A CHURCH, JR H N SPICER Alternates LEWIS W FRANCIS LOUIS D HUNTOON F T RUBIDGE

Jan 1, 1923

By A. M. Radigan, W. G. Prast

Various industrial minerals that are traded internationally receive support from governments, enabling these materials to be more competitive. The role of government in encouraging nonmetallics exports ranges from the ownership of an integrated mining company to partial or selective government ownership, to the sponsorship of exporter organizations. In certain cases, regional governments have a direct stake in the industrial minerals industry. This paper assesses the commercial impact of these involvements.

Jan 1, 1984

By A. G. Paithankar, G. B. Misra

Although certain physical mechanical properties of rocks have been claimed to give an estimate of penetration rate in percussive drilling, the authors' work shows that the correlation of penetration rate with individual rock properties is Poor. The authors have developed a good correlation between penetration rate and a set of rock properties but the relation is complex. Energy per unit volume has been used as a measure of penetration rate in percussive drilling by Hustrulid and Fairhurst; however, their test setup is large wing a full size drill bit. The authors determined the minimum energy for unit volume Ev min for any rock at the optimum index angle in a simple laboratory drop tester wing a sharp microbit with a tip angle of ll0°. This Ev min has been found to correlate well with penetration rate obtained in controlled laboratory drilling in different rocks for different stages of bit wear. A comprehensive relation has been developed between penetration rate and Ev min.

Jan 1, 1981

By S. Norton

GEORGE C. FOOTS, Port Henry, N. Y. (written discussion).-The paper by Mr. Norton and Mr. LeFevre will bear the most careful consideration by all interested in the iron business, particularly in the East. There is much information contained therein which should be emphasized. The idea of handling iron-bearing rock in quantities comparable to the porphyry coppers does seem at first blush to be beyond the pale of commercial possibility. Yet, today in the Adirondack region 25 per cent.

Jan 4, 1917

By J. L. Whitlock

An attached growth aerobic biological treatment process has been developed at Homestake Mining Co.'s Lead operation which not only oxidizes free and complexed cyanides, including the stable iron complexed cyanides, but also thiocyanate, and the oxidation byproduct ammonia. Through the employment of a mutant strain of bacteria which has been gradually and specifically acclimated to the waste, these potential pollutants are mineralized to relatively harmless sulfates, carbonates, and nitrates. The resultant effluent, through toxicological testing, has been shown compatible with the receiving stream, which serves as a cold water marginal trout fishery.

Jan 1, 1985

The age of specialization has made man increasingly dependent on a larger number of different metals and minerals. Overexploitation during World War II and lavish squandering of irreplaceable mineral wealth in the past has resulted in the rapidly approaching exhaustion of some of the major domestic ore sources. History clearly points out that the United States cannot continue to be a world power on an "import to survive" policy. A constructive program of development and appraisal of the nation's mineral wealth, including the planned conservation of her resources, must be adopted. Strictly speaking, conservation of minerals must mean the orderly exploitation of our resources and the prevention of waste in use, with due regard for the future. Real concern for the future may not extend beyond a few generations. Eventually science and invention should take care of the problems arising from shortages of some minerals, and the national defense aspects of domestic deficiencies can be provided for by stock piling and other measures. Early conservationists had this viewpoint; but with a rapidly developing industry and population, a farsighted policy that would deny full realization of immediate ambitions became unpopular. Consequently, the politically minded conservationist broadened the concept to include "prudent use of resources" and brought under the conservation umbrella

Jan 1, 1950

By N. A. Ziegler

A CERTAIN amount of interest has been indicated recently in the resistance to oxidation at high temperatures of iron-aluminum alloys (rich in iron). Hautman1 published a paper in which some interesting results are given. According to his paper, only alloys containing at least 8 per cent aluminum indicate a marked improvement in their resistance to oxidation. At about this aluminum content, however, alloys become brittle, which considerably reduces their commercial value. About two years ago the author performed a series of experiments, the results of which are presented here. A series of iron-aluminum-carbon alloys was prepared by melting electrolytic iron, aluminum and high-carbon iron alloy in an induction vacuum furnace.2 The list of these alloys is given in Table 1. Each alloy was forged in the ordinary way to

Jan 1, 1932

By Homer Turner

COALS, other than anthracite, have been so thoroughly studied under the microscope during recent years, that we now know what kinds of plants and what parts of plants form the bulk of lower rank coals from peat to bituminous coal. The microscope has also shown the state of preservation of such vegetation as well as the nature and distribution of products of plant decay. These and further details have been ascertained mainly through the employment of two methods of attack, section cutting and maceration. Anthracite has failed to respond to these methods, so well adapted to the study of lower rank coals and, therefore, has been neglected by investigators to such an extent that there is much doubt as to its microscopical characteristics. The object of this paper is to lift anthracite from its realm of obscurity by demonstrating the wealth of microscopical detail that is revealed when reflected light is used on a properly polished and etched surface and, further, to show the relationship between anthracite and bituminous coal.

Jan 2, 1925

By H. W. Paxton, C. C. Busby

IT has been shown previously' that strain aging can markedly improve the tensile properties of low carbon martensites, especially the yield-tensile ratio, without seriously affecting the ductility. In view of interest in high strength steels, an investigation has been made of the effect of strain aging following tension or rolling on the tensile properties of A1S1 4340 in an attempt to obtain a tensile

Jan 1, 1957