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By S. K. Tarby, V. S. Robinson III

A number of experimental determinations of the vapor pressure of liquid silver have been reported in the literature. 1-8 This communication presents additional data for the vapor pressure of liquid silver measured in the temperature range of 1450° to 1600°C and summarizes the results of previous investigations. The results reported here were obtained as part of a

Jan 1, 1969

By F. Keller

SOME PHRASEMAKER has aptly said that nature made aluminum light but research made it strong. Research has been a vital element in the past progress of the aluminum industry and its future growth likewise depends upon the application of the results of research. The role of aluminum products in World War II is well known and this metal will certainly be increasingly important in the postwar world. Some of the principal developments in the war years were in the field of high-strength aluminum alloys. New and stronger alloys were developed which enabled designers to get increased speed and performance in our fighter planes and bombers. The aircraft industry will continue to use these new materials for peacetime passenger and cargo airplanes. High-strength alloys will also find structural applications in trucks, buses, trains, ships, and bridges.

Jan 1, 1946

By James S. Baker

LARGER than continental United States but with only about one third the population, Brazil is a land of enormous potential wealth, waiting to be developed. During a recent visit to that country I saw Brazil at war and learned about some of the recent mineral developments. Many engineers and geologists have been sent to Brazil by various U. S. Government agencies to assist the Brazilian producers and co-operate with the Brazilian Government in producing needed war minerals. The Foreign Economic Administration staff of engineers has been active and through their assistance to the Brazilian producers, steadily increasing quantities of strategic minerals were provided to aid the United Nations' war effort. Mineral wealth has been found in almost every state of Brazil. Many mineral deposits have been discovered during the war period. Examples are: barite near Bahia; the tungsten and molybdenum deposits in Rio Grande do Norte; and corundum, beryl, and tungsten ores in Ceara.

Jan 1, 1945

By AIME AIME

TWO papers, "Calcium, Strontium, and Barium Metals," by Charles Hardy and Paul M. Tyler, and "The Mining of Gems and Ornamental Stones by American Indians," by Sydney H. Ball, were presented before the Rare Minerals and Metals group at its session Tuesday afternoon in the Auditorium. Donald M. Liddell, chairman, presided. Mr. Tyler summarized the first paper, outlining the uses, history, occurrence, manufacture, production and trade, markets and prices of the three metals. In discussion, in response to the chairman's query on "what are they doing in Russia with calcium, strontium, and barium," Guy C. Riddell replied that nothing is being done on a production basis. The great rare metals plant in Moscow is active, however, on other elements. "They are making radium chloride, uranium oxide, vanadium, cadmium, tungsten, molybdenum, selenium, antimony compounds; and mercury, nickel and arsenic are under production at interior plants. The rare metals plant is busily conducting research on beryllium, rhenium, lithium, bismuth, strontium and zirconium. These are the main rare metal activities. Much hard-alloy work. for cutting and facing, is under way:

Jan 1, 1933

By R. E. McNulty, R. D. Heidenreich, C. H. Gerould

TIIE electron microscope techniques and their application to magnesium alloys that are to be discussed in this paper are the result of research at The Dow Chemical Co. over the past three years. The view- point underlying the work is not wholly metallurgical, but has evolved through a variety of problems related to the physics and chemistry of surfaces. It can be said that the interest and stimulus were closely associated with a desire to employ effectively the electron microscope in research concerning the properties of solids as related to their physical structure. Only a portion of this work will be described here, and, consequently, many points of interest and debate are of necessity either only briefly recognized or are completely omitted. As has been pointed out by Desch,1 a great deal of the knowledge of the structure of metals has been obtained through microscopic studies of the surfaces of metallic specimens prepared in a particular manner. This information, when added to that obtained by means of thermal, electrical, X-ray, dilatometric and other methods, has been of great value both from a theoretical and a practical view- point. With the introduction of new instruments such as the electron diffraction camera and the electron microscope, it would be expected that still more information could be obtained. These two instruments have in many instances been very effective when directed toward the investigation of metallic surfaces, provided the proper methods of surface preparation were employed. Experience shows that the problems of surface preparation greatly limit the general application of these instruments to metallographic studies. It was found necessary to discard the standard metallographic procedures in applying the electron microscope to magnesium alloys and to work out new methods, which were required to satisfy certain conditions. These methods are unique to magnesium only in the specific chemical reactions occurring during etching. The presentation of the methods and results will be ordered as follows: I. Electron Microscopy of Surfaces. 2. Surface Preparation of Magnesium Alloys. 3. Discussion of Microstructures. a. Pure Magnesium and Single-crystal Studies. b. Types of Precipitation. c. Some Common Structures. d. Special Micrographs and Techniques. e. Structure of Mg-A1 Solid Solutions. 4. Correlation of "Fine Structure" with Corrosion Behavior of Magnesium Alloys.

Jan 1, 1946

By Charles Barrett

RECRYSTALLIZATION textures-the orientations of grains after recrys-tallization-have been studied extensively not only because of their metallurgical importance but also because of the information they yield regarding the atomic movements during recrystallization. Recrystallized grains must possess the same orientations as the submicroscopic nuclei from which they have grown, and thus they offer a direct road by which experimenters can penetrate the submicroscopic realm. Many perplexing results have come of these studies, but one of the most striking has been the apparent difference in behavior between single crystals and polycrystalline grains. For example, Burgers and Louwerse have shown' that when single crystals of aluminum are deformed by compression and are recrystallized (at 600° C.) the new grains appear with orientations that are different from the orientations of the deformed crystal in which they grew; but polycrystalline specimens, on the other hand, appear to have a [110] fiber texture both before and after recrystal-lization and thus to retain their texture during recrystallization. This apparent difference between the habits of single crystals and small grains is the subject of the first part of the present research and has been explained by findings reported herein. A similar situation appears to exist for aluminum when elongated or drawn into wires, for single crystals alter their orientation2,3 and polycrystalline wires retain their texture 4,1 6 upon recrystallization after elongation (at least with high-purity alumi-num), and it is possible that the explanation found in this paper for compression can be extended to cover elongation and other types of deformation as well. The second part of this paper deals with the theory of recrystallization textures. In the most successful theory for aluminum recrystallized after compression,1 much weight is given to the orientation of highly stressed nuclei in the deformed material. Taylor's "local distortions" are assumed to exist along the slip planes where displacement has occurred, consisting of fragments rotated in a specific way with reference to the slip plane and slip direction; namely, about an axis lying in the slip plane perpendicular to the slip direction. 1,7,8,9

Jan 1, 1940

By Clarence Merritt

STAINLESS iron, as mild stainless steel is usually called, an alloy ranging from 11.50 to 15.00 per cent chromium with carbon under 0.12 per cent, has been considered to be not appreciably affected in respect to corrosion resistance by heat treatment. This metal, while one of the most widely used of the "straight" chromium stainless alloys, has failed in many applications because of insufficient information regarding heat treatment. These failures have been attributed to many possible causes from an inherent lack of resistance to corrosion and misapplication to mysterious electrolytic effects or comparatively minute non-metallic inclusions. Many uses for a steel with such excellent physical properties is are latent in this alloy have been lost on account of corrosion failures which could have been avoided by applying proper heat treatment. The alloy has not received the recognition or attention it should because of the fact that' the details of its metallurgical behavior were not thoroughly understood. Response to heat treatment of the steel is well known as regards tensile properties, 1,2 but its application has been for improvement in tensile characteristics or on account of machining considerations rather than for corrosion prevention. The potential user of this steel has not been clearly advised in papers, either technical or commercial, that have been written about it in the last 10 years or more, of particular features that are of prime importance in developing the excellent properties of this metal. The data to be presented in this paper are concerned mainly with the effect of heat treatment on the corrosion resistance, but a study has also been made of the concurrent microstructural changes and an explanation developed for the phenomena revealed, as well as a correlation to the other physical properties-hardness, tensile characteristics and impact strength. Stainless steel, largely used for cutlery purposes, an alloy of approximately 13.00 per cent Cr with 0.30 per cent C, must be hardened and the surface prepared by polishing or pickling for best resistance to staining and corrosion.3 Monypenny reports that a loss of hardness is

Jan 1, 1932

By Charles S. Barrett

Recrystallization textures—thc orientations of grains after recrys-tallization—have been studied extensively not only because of their metallurgical importance but also because of the information they yield regarding the atomic movements during reerystallization. Recrystallized grains must possess the same orientations as the submicroscopic nuclei from which they have grown, and thus they offer a direet road by which experimenters can penetrate the submicroscopic realm. Many perplexing results have come of these studies, but one of the most striking has been the apparent difference in behavior between single crystals and polyerystalline grains. For example, Burgers and Louwerse have shown1 that when single crystals of aluminum are deformed by compression and are reerystallized (at 600' C.) the new grains appear with orientations that are different from the orientations of the deformed crystal in which they grew; but polycrystalline specimens, on the other hand, appear to have a [110] fiber texture both before and after reerystallization and thus to retain their texture during recrystallization. This apparent difference between the habits of single crystals and small grains is the subject of the first part of the present research and has been explained by findings reported herein. A similar situation appears to exist for aluminum when elongated or drawn into wires, for single crystals alter their orientation 2,3 and polycrystalline wires retain their texture"5*" upon recrystallization after elongation (at least with high-purity aluminum), and it is possible that the explanation found in this paper for compression can be extended to cover elongatioil and other types of deformation as well. The second part of this paper deals with the theory of reerystallization textures. In the most successful theory for aluminum reerystallized after compression,1 much weight is given to the orientation of highly stressed nuclei in the deformed material. Taylor's "local distortions" arc assumed to exist along the slip planes where displacement has occurred, consisting of fragments rotated in a specific way with reference to the slip plane and slip direction; namely, about an axis lying in the slip plane perpendicular to the slip direction.1,7,89

Jan 1, 1940

By Charles S. Barrett

Recrystallization textures—thc orientations of grains after recrys-tallization—have been studied extensively not only because of their metallurgical importance but also because of the information they yield regarding the atomic movements during reerystallization. Recrystallized grains must possess the same orientations as the submicroscopic nuclei from which they have grown, and thus they offer a direet road by which experimenters can penetrate the submicroscopic realm. Many perplexing results have come of these studies, but one of the most striking has been the apparent difference in behavior between single crystals and polyerystalline grains. For example, Burgers and Louwerse have shown1 that when single crystals of aluminum are deformed by compression and are reerystallized (at 600' C.) the new grains appear with orientations that are different from the orientations of the deformed crystal in which they grew; but polycrystalline specimens, on the other hand, appear to have a [110] fiber texture both before and after reerystallization and thus to retain their texture during recrystallization. This apparent difference between the habits of single crystals and small grains is the subject of the first part of the present research and has been explained by findings reported herein. A similar situation appears to exist for aluminum when elongated or drawn into wires, for single crystals alter their orientation 2,3 and polycrystalline wires retain their texture"5*" upon recrystallization after elongation (at least with high-purity aluminum), and it is possible that the explanation found in this paper for compression can be extended to cover elongatioil and other types of deformation as well. The second part of this paper deals with the theory of reerystallization textures. In the most successful theory for aluminum reerystallized after compression,1 much weight is given to the orientation of highly stressed nuclei in the deformed material. Taylor's "local distortions" arc assumed to exist along the slip planes where displacement has occurred, consisting of fragments rotated in a specific way with reference to the slip plane and slip direction; namely, about an axis lying in the slip plane perpendicular to the slip direction.1,7,89

Jan 1, 1940

By G. E. Murray

Lead blast-furnace work at Trail is unique in that this is the only plant in the world where blast-furnace smelting on a large scale for both lead and zinc recovery is carried on under one management. On this account the factors that determine economic practice differ from those of other lead smelters. In addition to this different metallurgical outlook, a great deal of structural investigation has been carried on, which has resulted in the development of a furnace which should prove of interest to all who are faced with similar problems. This description may be conveniently divided into various heads as follows: (1) General—make-up of charge, etc.; (2) structural—(a) hoods and charging methods, (b) shaft construction, (c) crucible construction; (3) handling slag; (4) handling bullion; (5) metallurgy. The Charge The Trail plant is an old one, on a congested site. As with most old plants, this limits the method of charge preparation. In general, lead metallurgists will agree that sinter when it reaches the blast furnace should contain as small an amount as possible of actual fines. There would be some difference of opinion as to the maximum size as well as of the minimum required, but to obtain the optimum condition some form of screening is indicated. This screening should take place immediately before the blast furnace if possible, and because sinter deteriorates in storage there should be as little as possible. There should also be the minimum amount of handling between the sinter machines and the furnaces. Unfortunately, at Trail the sinter must be handled considerably before it is charged to the furnace, and no feasible scheme of screening has yet been devised. Trail practice, then, demands that the sinter be a strong one physically. Dependent upon the amount of lead in it, it has been found advantageous to incorporate granulated slag into the final sinter, the amount varying inversely as the lead content. The addition of this slag makes a harder sinter, which arrives at the blast furnace in a better condition, but it entails some lack of efficiency, because desulphuriza-tion is not so rapid nor so complete.

Jan 1, 1937

By A. W. Gauger

For perhaps one hundred years scientists have been engaged in attempts at devising a satisfactory method of classification of coal. During this time many charts, tables and graphs have been proposed, some of which have had considerable merit, but no one system has been found to be applicable to all ranks of coal, nor has any one system received general acceptance. In many of the proposals, water eliminated between room temperature and 105" C. has been regarded as extraneous matter and calculations have been made to the air-dry or water-free basis. Such methods of calculation do not lend themselves to satisfactory grouping of the high-moisture coals.1, 2 A consideration not only of the properties of the high-moisture coals and their behavior on drying but of the generally accepted ideas of the coalification process and the role of water in this process indicates that water is an essential constituent of all coals and therefore should not be neglected. For example, in such low-rank coals as the lignites of the Northern Great Plains' deposits the inherent moisture of the lignite as mined plays a very important part in the physical properties thereof. Freshly mined lignite contains upwards of 30 per cent water and is extremely tough and resistant to shock. Upon exposure to the atmosphere, the lump loses part of its moisture and checks and splits, leaving a friable and broken up residue. So far as we have been able to determine, water is the only thing lost in this process and we are forced to the conclusion that moisture plays an extremely important part in the structural properties of the original lignite. With reference to the coalification process, Mack and Hulett3 pointed out in 1917 the important part that water played therein. They observed that water cannot be removed from peat or coal by pressure alone, but only as the result of chemical reaction, and suggested that peat in its early stages may be largely a hydrosol. Slow chemical changes occur over a long period of time until finally the mass becomes more largely a hydrogel. These views are substantiated to some extent by the experi-

Jan 1, 1932

By L. J. Ebert, G. Sachs, W. F. Brown

Isothermal transformation, or "aus-tempering," of a carbon-containing aus-tenite at elevated temperatures yields so-called "intermediate products." Their structure and properties are, for a given hardness, rather different from those of "tempered martensite" obtained on conventional quenching and tempering.' Several investigators2,3 have found that for high carbon and slightly alloyed steels the intermediate products formed at temperatures close to that of the martensite reaction possess strength properties superior to those of tempered martensite. The structure of these low temperature, intermediate products is generally acicular (bainite) but clearly different from that of martensite. However, at higher austempering temperatures, between 1000 and 1300°F (540 and 700°C) carbon steels were found to exhibit a rather low ductility.4,5 Thus notch bar tensile tests showed the ratio between notch strength and regular tensile strength to decrease with increasing austempering temperature. For ductilities below a few percent this notch strength ratio is a measure of ductility, according to investigations on low alloy steels.637 Furthermore the presence of intermediate products formed unintentionally on quenching was considered as responsible for the low ductility and impact energy of some heat treated steels,8 These intermediate products could result from partial transformation at the so-called "nose-temperature" where the rate of the transformation is a maximum. Tempering improved such mixtures of martensite and intermediate products, their properties approaching those of tempered martensite of equal hardness. The following investigation constitutes an attempt to determine certain strength properties of a partially austempered and subsequently quenched low alloy steel, namely, a chromium steel (SAE 5140) The structures formed by such a treatment should consist of a mixture of intermediate products formed on austempering and a martensite formed on oil quenching from the austempering temperature. It was intended, by varying the austempering time, to vary the quantity of the intermediate products between zero and 100 pct. The austempering temperature of 860°F was selected after extensive preliminary tests close to the nose-temperature. Austempering at this temperature yielded an acicular intermediate product. .Additional tests under less exacting conditions were made for an austempering temperature of 950°F where the intermediate product appeared to be very fine pearlite. To determine the effects of tempering on structures containing various amounts of

Jan 1, 1949

By G. Sachs, L. J. Ebert, W. F. Brown

Isothermal transformation, or "aus-tempering," of a carbon-containing aus-tenite at elevated temperatures yields so-called "intermediate products." Their structure and properties are, for a given hardness, rather different from those of "tempered martensite" obtained on conventional quenching and tempering.' Several investigators2,3 have found that for high carbon and slightly alloyed steels the intermediate products formed at temperatures close to that of the martensite reaction possess strength properties superior to those of tempered martensite. The structure of these low temperature, intermediate products is generally acicular (bainite) but clearly different from that of martensite. However, at higher austempering temperatures, between 1000 and 1300°F (540 and 700°C) carbon steels were found to exhibit a rather low ductility.4,5 Thus notch bar tensile tests showed the ratio between notch strength and regular tensile strength to decrease with increasing austempering temperature. For ductilities below a few percent this notch strength ratio is a measure of ductility, according to investigations on low alloy steels.637 Furthermore the presence of intermediate products formed unintentionally on quenching was considered as responsible for the low ductility and impact energy of some heat treated steels,8 These intermediate products could result from partial transformation at the so-called "nose-temperature" where the rate of the transformation is a maximum. Tempering improved such mixtures of martensite and intermediate products, their properties approaching those of tempered martensite of equal hardness. The following investigation constitutes an attempt to determine certain strength properties of a partially austempered and subsequently quenched low alloy steel, namely, a chromium steel (SAE 5140) The structures formed by such a treatment should consist of a mixture of intermediate products formed on austempering and a martensite formed on oil quenching from the austempering temperature. It was intended, by varying the austempering time, to vary the quantity of the intermediate products between zero and 100 pct. The austempering temperature of 860°F was selected after extensive preliminary tests close to the nose-temperature. Austempering at this temperature yielded an acicular intermediate product. .Additional tests under less exacting conditions were made for an austempering temperature of 950°F where the intermediate product appeared to be very fine pearlite. To determine the effects of tempering on structures containing various amounts of

Jan 1, 1949

Adolph Thies, Haile Gold-Mine, S. C.: I have little to add to what my friends Messrs. Nitze and Wilkens have said on this subject. What I have done in mining during the last fortyone years, partly in this country and partly in South Africa (though not, as to Africa, in the diamond- or the gold-fields,

Jan 1, 1896

By P. E. Baker

A paper by A. S. Odeh' expounds a capillary-flow theory which purportedly provides a mechanism whereby relative permeability depends on oil-water viscosity ratio and may be greater than unity for high viscosity ratios. Core-measurement results are presented to support the theoretical development. This paper presents arguments to indicate that (1) the theoretical treatment is basically incorrect, (2) data reported are insufficient to support the conclusions and (3) literature cited does not support the theory or the conclusions. PROPOSED MECHANISM The essence of Odeh's theory is that oil flows as a filament along the central portion of a straight, uniform capillary of radius r filling the tube to a radius ri. Surrounding the filament of oil is an annulus of water in which exists vortex motion but no net flow. The water is described as being in "microscopic but not macroscopic" motion. The oil filament is aided in its flow by moving upon the water vortexes as if on roller bearings. This process is presented as a steady-state flow condition. The first objection to the existence of vortexes in the presumed water layer is that the theory provides no mechanism whereby they can be established. This fact was mentioned by C. F. Weinaug in a discussion published with Odeh's paper. The capillary contains no irregularities or obstructions, and the water is not presumed to be in turbulent flow. Apparently, cylindrical symmetry is assumed; therefore, the supposed vortexes must be toroidal, the line of zero velocity being a circle concentric with and in a plane perpendicular to the axis of the capillary. This is a rather difficult picture to accept. The author referred to Yuster's statement' that he had observed the "spinning in place" of otherwise immobile water. Yuster's article does not describe the conditions under which this motion was observed or the means used to observe it. However, the article does make clear that the observed motion was not in a straight, uniform capillary but, rather, apparently oc-cured in some kind of dead-ended pore space. Obvious- ly, such a report cannot be considered as support for Odeh's concept of two-phase capillary flow.

By F. D. Rosi

IN the production of single crystals by the Bridg-man method of solidification from the melt in vacuum at a crucible lowering rate of 0.25 in. per hr, a cellular structure was frequently observed in copper and copper-base alloys at the terminal surface of the as-cast crystals (i.e., the surface representing the last portion of the crystal to solidify). The geometrical form of this structure varied from crystal to crystal, but, in general, could be classified as either hexagonal or quadrilateral. Fig. 1 shows examples of this cellular structure, which is similar to that reported by Buergerl and, more recently, by Pond and Kessler&apos; and Rutter and Chalmers. In the micrographs of Figs. lb and c, the cubic structure in the alloy crystals is obscured somewhat by excessive surface evaporation in the final stages of solidification. X-ray orientation studies indicate that the traces outlining the various geometrical forms correspond to octahedral planes, which are the planes of greatest reticular density in the face-centered cubic lattice. It would appear from this that the view first propounded by Bravais,4 that the surface energies and normal growth velocities of the different crystal planes are inversely proportional to their reticular densities, applies to this cellular structure, since those surviving are the planes of greatest atomic density. Thus, the observed variation in the geometrical form of this structure in crystals of different orientation is readily understandable from the distribution of the (111) planes in the standard {111}, (1101, and (1001 stereographic projections. Depending upon whether the crystal axis (i.e., the direction of crystallization) coincides with a <111>, <111>, or <100> direction, the cellular structure viewed from a surface perpendicular to the crystal axis will consist of a network of regular hexagons, skewed hexagons (with interfacial angles of 110" and 125"), or cubes, respectively. It follows, moreover, that off-orientations from these principal directions will yield modifications of these three basic geometric configurations. In this connection, it is interesting to note that the bounding planes of the hexagonal structure observed in tin by Rutter and Chalmers3 showed no preferred orientation.

Jan 1, 1954

By T. A. Rickard

Flaubert, as we know, laid stress on the selection of the right word, le mot juste, the precise epithet, the word that belongs to the thing. A sentence, or even a paragraph, may be spoiled by the use of a word that is not proper, that does not fit or is foreign to the meaning intended. An Australian mining expert is reported to have said: You have a property of considerable value, and what I saw warrants a good development of very rich cubicular galena, with gossan intermixed. &apos;Cubicular&apos; means `belonging to a small bedroom&apos;, a `cubicle&apos; being a sleeping compartment. He meant `cubic&apos;, of course. This is a malapropism, and reminds me of the lady from Chicago that, on her return from Europe, said how much she had enjoyed the rural parts of France, because, among other things, it was "so delightful to hear the French pheasants singing the mayonnaise to the tune of the Los Angelus". It is impossible to amalgamate coal-tar thoroughly with the pulp in the agitating-tank. In metallurgy, `amalgamate&apos; refers to the combination of mercury with one or both of the precious metals, forming an amalgam, which is an alloy of mercury with another metal. It differs from other alloys, such as brass or bronze, in being made without the aid of heat, inasmuch as mercury is molten at the ordinary temperature. The word comes to us from the Greek. through Old French and means `something soft&apos;. It is a mistake to use technical terms, having a specific meaning, for purposes that are foreign to that meaning. The writer of the quotation is not discussing any combination of metals; he is dealing with the physical process of mixing and is using &apos;amal-

Jan 1, 1931

By M. Gensamer, B. Lustman

A recent paper described, by means of stereographic pole figures, the preferred orientations produced by cold-rolling low-carbon steel of automobile-body grade. It was found that the surface of the sheet exhibited a deformation texture significantly different from the texture possessed by the inside of the sheet. Efforts to produce the surface texture by buffing a sample exhibiting the normal or inside texture, using a copper lap, have not been successful. In view of the data collected by Kurdjumow and Sachs2, it was suggested that the surface texture might be the result of partial recrystallization of the normal or inside texture. The recrystallization texture of cold-rolled mild steel was studied by Goss3, but he did not use the pole-figure method, so that his conclusions were in need of verification. For these reasons the work reported in here was undertaken. It had two objectives: (1) to study the general behavior of cold-rolled mild steel on recrystallization below the critical temperature Al, and (2) to attempt experimentally a demonstaration of the genesis suggested above for the surface texture in cold-rolled steel. The material was that used by Gensamer and Mehl, cold-rolled to 97.5 per cent reduction in thickness. Fig. 1 is an X-ray pinhole photo-gram of this material, taken with the beam transmitted perpendicular to the plane of the sheet, using a molybdenum target at 35 kv. with no filter. It is typical of the inside texture, but in it the deformation texture is better developed than in the samples that showed a well developed difference between the inside and surface samples. Specimens from this sheet, which was 0.005 in. thick, were annealed for 5 min. at various temperatures in a lead bath. After about 0.0005 in. had been etched from both surfaces, X-ray photograms were prepared, using the technique described in the earlier paper1. Figs. 2 to 6 are photograms of the annealed sheet, at 566, 571, 577, 580 and 650" C. (1050&apos; to 1202" F.), in order. Fig. 2 shows that 5 min.

Jan 1, 1937

By A. W. Gauger

Fox perhaps one hundred years scientists have been engaged in attempts at devising a satisfactory method of classification of coal. During this time many charts, tables and graphs have been proposed, some of which have had considerable merit, but no one system has been found to be applicable to all ranks of coal, nor has any one system received general acceptance. In many of the proposals, water eliminated between room temperature and 105° C. has been regarded as extraneous matter and calculations have been made to the air-dry or water-free basis. Such methods of. calculation do not lend themselves to satisfactory grouping of the high-moisture coals.1,2 A consideration not only of the properties of the high-moisture coals and their behavior on drying but of the generally accepted ideas of the coalification process and the role of water in this process indicates that water is an essential constituent of all coals and therefore should not be neglected. For example, in such low-rank coals as the lignites of the Northern Great Plains&apos; deposits the inherent moisture of the lignite as mined plays a very important part in the physical properties thereof. Freshly mined lignite contains upwards of 30 per cent water and is extremely tough and resistant to shock. Upon exposure to the atmosphere, the lump loses part of its moisture and checks and splits, leaving a friable and broken up residue. So far as we have been able to determine, water is the only thing lost in this process and we are forced to the conclusion that moisture plays an extremely important part in the structural properties of the original lignite. With reference to the coalification process, Mack and Hulett3 pointed out in 1917 the important part that water played therein. They observed that water cannot be removed from peat or coal by pressure alone, but only as the result of chemical reaction, and suggested that peat in its early stages may be largely a hydrosol. Slow chemical changes occur over a long period of time until finally the mass becomes more largely a hydrogel. These views are substantiated to some extent by the experi-

Jan 1, 1932

President Mrs. Herman A. Prosser 1001 Park Avenue New York 28, N. Y First Vice-President Mrs. David E Park 115 East 67th Street New York 22, N Y. Second Vice-President Mrs Oliver Bowles 5000 Massachusetts Ave , N W. Wash 16, D C Third Vice-President Mrs. H Bobinson Plate 1215 Vancouver Avenue Burlingame, Calif

Jan 1, 1952