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By W. C. Schroeder, A. A. Berk

Practical experience has shown that at elevated temperatures solutions containing sodium hydroxide may attack stressed steel in a manner that cannot be explained in terms of ordinary corrosion. Because the ductility of the metal has been greatly reduced during the reaction, the entire phenomenon is usually called "embrittlement." Thus, after several years of operation caustic evaporators have been so badly embrittled that rivets could be cracked off with the blow of a hammer. Since fine intergranular cracks are almost always present in the zone of fracture, it has often been assumed that a process of selective corrosion in grain boundaries was responsible for the failure, although this has not been clearly proved experimentally. Concentrations of sodium hydroxide below those necessary for the uniform, rapid attack of the steel surface are reported to be most effective in producing embrittlement2, 3. In the operation of steam boilers a similar type of failure has been found, mainly in riveted seams or other capillary spaces where the solution may concentrate and where high stresses may also exist. It is believed that in such localized areas the dissolved solids may reach a value many times the few hundred parts per million prevalent in the body of the boiler. While this type of boiler failure has been the subject of investigation for a period of 20 years1, an understanding of its mechanism and a rational basis for complete protection have not yet been secured. To procure this information the present investigation was

Jan 1, 1936

By A. A. Berk, W. C. Schroeder

Practical experience has shown that at elevated temperatures solutions containing sodium hydroxide may attack stressed steel in a manner that cannot be explained in terms of ordinary corrosion. Because the ductility of the metal has been greatly reduced during the reaction, the entire phenomenon is usually called "embrittlement." Thus, after several years of operation caustic evaporators have been so badly embrittled that rivets could be cracked off with the blow of a hammer. Since fine intergranular cracks are almost always present in the zone of fracture, it has often been assumed that a process of selective corrosion in grain boundaries was responsible for the failure, although this has not been clearly proved experimentally. Concentrations of sodium hydroxide below those necessary for the uniform, rapid attack of the steel surface are reported to be most effective in producing embrittlement2, 3. In the operation of steam boilers a similar type of failure has been found, mainly in riveted seams or other capillary spaces where the solution may concentrate and where high stresses may also exist. It is believed that in such localized areas the dissolved solids may reach a value many times the few hundred parts per million prevalent in the body of the boiler. While this type of boiler failure has been the subject of investigation for a period of 20 years1, an understanding of its mechanism and a rational basis for complete protection have not yet been secured. To procure this information the present investigation was

Jan 1, 1936

By C. R. Fulton

The idea of making permanent magnets by sintering is not a new one, but until the introduction of the iron-nickel-aluminum permanent-magnet alloys there was little need for such a process. Permanent-magnet alloys in use up to the time of this development could be forged and machined to the exact size or shape required without too much difficulty. These new Fe-Ni-A1 alloys, which have become known as Alnico in this country, soon became very popular because of their superior magnetic properties, but when they were made by casting they did have some disadvantages when compared with the older type of permanent-magnet steels. Among these disadvantages were the following: 1. It was almost essential that they be cast to size, since they could not be readily forged or machined. The material could be ground but this was quite expensive, particularly for small magnets in large quantities. 2. The material had a large grain size and was mechanically weak. 3. Close tolerances could not be held and on small magnets this meant grinding almost the entire magnet. Because of the brittle nature of the material, there was considerable loss due to chipping and cracking during these grinding operations. 4. Because of its high aluminum content, the molten alloy had a high surface tension. It was difficult to prevent loss of aluminum by oxidation during the melting operation. In view of these difficulties it is not hard to understand why a process for sintering alnico was developed, or why sintered alnico has come into such widespread use in recent years. It might be well to qualify this by saying that it has come into widespread use for small magnets weighing 2 oz. and less, of the type shown on Fig. I. In this size range, sintered alnico has been able to compete in price with cast alnico. Magnets larger in size, of the type shown on Fig. 2, can be made but they do not compare favorably in price with the cast material. An idea of the range of sizes that have been produced is given by Fig. 3, which shows a small magnet weighing 0.006 oz. and a large magnet with a steel insert weighing 4 lb., both made from sintered alnico. Magnets weighing more than 2 oz., however, should not be made from sintered

Jan 1, 1945

By Richard Pearce

In the treatment of auriferous copper containing bismuth, I have recently observed a small quantity of a grayish-white alloy, which on examination, proved to be Bi containing in solution, as it were, a crystalline alloy of Bi and Au. This compound makes its appearance on the surface of the auriferous Cu in small globules as the latter cools. These globules are rapidly attacked by nitric acid, and fine needleshaped crystals of Bi and Au separate out. They arc insoluble even in strong nitric acid. On examination, the crystals mere found to contain : Gold, 69.94 per cent.; silver, 0.63 per cent. ; bismuth, 29.43 per cent. (No. I).* The residue is very fusible, and at a temperature considerably below its melting-point it oxidizes rapidly, changing from its original gray color to a greenish-yellow (No. 2). On melting in a crucible under flux, a bronze-colored alloy is formed that has the specific gravity 15.47—somewhat higher than the calculated specific gravity of a simple mixture of the two metals in the proportions named. Alloys of Gold and Silver.—In following out my investigations by repeated examinations of this alloy formed at different times, I found that, in dissolving a miscellaneous lot of the alloy in nitric acid, some gold-yellow crystals were formed, which I succeeded in separating from the BiAu alloy by washing. These yellow crystals, under the microscope, showed distinct, regular, octahedral faces, and on examination they were found to be a crystalline alloy of Au and

Jan 1, 1885

By F. C. Langenberg, R. W. Lindsay

COPPER sometimes is added to steel and cast iron as an alloying element to improve or impart specific properties. However, in some steels it exerts an impurity effect in impairing response to fabrication by hot working and deep drawing. The resid-

Jan 1, 1955

In cooperation with the United States Bureau of Mines and the Idaho Bureau of Mines and Geology, the University of Idaho offers in the School of Mines a number of fellowships. These fellowships are open to college graduates who have had good training in mining, metallurgy, or chemistry, and who are qualified to undertake research work. The income of each fellowship is $720 a year for the 12 mo. beginning July 1, 1919. Fellows will register as students in the University of Idaho and become candidates for the degree of Master of Science in Mining or Metallurgy (unless this or an equivalent degree has been earned). Their class work-will he directed by the heads of the departments of instruction, but the greater portion of their time will be spent in research work under the direction of the Bureau of Mines staff resident at the University. The purpose f this work is to undertake the solution of definite problems confronting the mining and metallurgical industries of the State of Idaho. For 1919-20 the following subjects are being considered: 1. Flotation-with especial reference to differential separation of various minerals. 2. Availability of western wood oils for flotation purposes. 3. Treatment of the complex gold-silver ores of southern Idaho. 4. Ore-dressing problems. 5. Mining problems. Applications, with certified copy of collegiate record, statement of professional experience, and names and address of three references, should be addressed to The Dean. School of Mines. Moscow Idaho_

Jan 6, 1919

THE LIFE and works of Alexander Agassiz, first president of the Calumet & Hecla Mining Co., were recalled to memory when a monument bearing his statue was unveiled in Agassiz Park, at Calumet, Mich., on Sept. 26, The statue is the work of Paul W. Bartlett, of New York, and was erected by George R. Agassiz, eldest son of Alexander Agassiz. We are indebted to Rodolphe L. Agassiz, now president of the Calumet & Hecla Consolidated, for the accompanying photograph of the statue. The principal address at the unveiling ceremony was delivered by Allen F. Rees, of Houghton, who said, in part: To the world at large Alexander Agassiz was preeminently the man of science. With all his devotion to the industrial life of this district, he found the time to devote to the con-tinuation of his work of scientific research which had been the life work of his fa-ther, Louis Agassiz. Not only did he acquire eminence for his scientific at-tainments and learn-ing, but he was recognized and hon-ored throughout the civilized world for his achievements and accomplishments in the realm of original research. His work in the fields of nat-ural science, in oceanography, in marine zoology, and in other similar lines of research, has added much to our knowledge of the world's mysteries. His life was one of accomplishment also in the industrial world. The union in one life of acknowledged achievement as a scientist and the accomplishment of great results in the prac-tical industrial world is a rare thing, and its possibility has never been exemplified in greater measure than in his life and its results.

Jan 11, 1923

By Alan Stanley

THE MacIntyre Development of National Lead Co. is located at Tahawus, N. Y., in the heart of the Adirondack Mountains. Operations involve the mining and concentrating of a titaniferous iron ore to produce ilmenite and magnetite concentrates. A general description of the operation and metallurgy has been given by Frank R. Milliken.' Pigment plant production demands that the MacIntyre mill produce a 44.7 pct TiO, ilmenite concentrate. To achieve the required ilmenite grade and tonnage it is important that the table concentrate grade be closely controlled. Unfortunately, however, the titaniferous orebody which feeds the MacIntyre mill is not uniform. Ore dressing characteristics vary from one end of the orebody to the other, and from • one level to the next. The changeable nature of the mill feed precludes a single adjustment of the equipment for long periods of time. Thus the operators must constantly watch the equipment to insure a uniform concentrate from the fine and coarse tables and Wetherills, or dry magnetic separators. Chemical assaying of mill products requires about 4 hr from the time the sample is taken until assay results are obtained, and this is available only on a two-shift basis. The ore may change rapidly, even several times during a shift, so that assay results lose most of their control value by the time they are reported to the mill operating crew. Members of the crew have therefore tried to evaluate the table and Wetherill concentrate by visual inspection, since through long experience the shift operators, under most circumstances, can gage closely the grade of the mill products. However, there are times when the physical nature of the ore is radically different from normal. Under these conditions visual inspection is of no value, and at such times final ilmenite as low as 43 pct TiO, has been produced and shipped before the assay results have been received. The specific gravity method of assaying for TiO, has been attempted to eliminate the shipping of ilmenite below normal grade as well as to help control day to day and hour to hour mill production. Table I shows the minerals found in the MacIntyre ore along with their average weight proportions and specific gravities. The first two products considered for the specific gravity method were fine and coarse table concentrates. It was reasoned that these products were essentially ilmenite with the higher specific gravity gangue minerals. Since they were always produced the same way, and the desired grade of TiO, was always constant, the specific gravity of these materials would increase or decrease as the amount of ilmenite increased or decreased. Thus for table concentrates which assayed 40 pct TiOz a constant gravity would invariably be obtained, and as the TiO, value changed the specific gravity would change in direct proportion. The third product considered was Wetherill ilmenite. It was assumed that a desired grade of 44.7 pct Ti02 would also always contain the same amount and type of gangue minerals along with the ilmenite, and thus would always have the same specific gravity. As the TiO, value of the ilmenite concentrate changed so would its specific gravity. Dr. Kenneth Vincent, chief metallurgist of the Baroid Division of National Lead Co. at Magnet Grove, Ark., ran specific gravity tests on 17 samples of the desired products. The lowest specific gravity reading assayed the lowest in TiO, and as the specific gravity increased the trend was for the TiO, assay to increase, see Fig. 1. Since these results warranted further investigation, a 500-g capacity Torsion balance and 250 ml Le Chatelier specific gravity bottles were obtained. Shift samples of fine table concentrate, coarse table concentrate, and final ilmenite were tested. Each sample was split and 85 g weighed on the Torsion balance. The Le Chatelier bottle was filled with water to a zero mark. To avoid wetting the neck of the bottle it was found necessary to do this

Jan 1, 1953

By Alan Stanley

THE MacIntyre Development of National Lead Co. is located at Tahawus, N. Y., in the heart of the Adirondack Mountains. Operations involve the mining and concentrating of a titaniferous iron ore to produce ilmenite and magnetite concentrates. A general description of the operation and metallurgy has been given by Frank R. Milliken.' Pigment plant production demands that the MacIntyre mill produce a 44.7 pct TiO, ilmenite concentrate. To achieve the required ilmenite grade and tonnage it is important that the table concentrate grade be closely controlled. Unfortunately, however, the titaniferous orebody which feeds the MacIntyre mill is not uniform. Ore dressing characteristics vary from one end of the orebody to the other, and from • one level to the next. The changeable nature of the mill feed precludes a single adjustment of the equipment for long periods of time. Thus the operators must constantly watch the equipment to insure a uniform concentrate from the fine and coarse tables and Wetherills, or dry magnetic separators. Chemical assaying of mill products requires about 4 hr from the time the sample is taken until assay results are obtained, and this is available only on a two-shift basis. The ore may change rapidly, even several times during a shift, so that assay results lose most of their control value by the time they are reported to the mill operating crew. Members of the crew have therefore tried to evaluate the table and Wetherill concentrate by visual inspection, since through long experience the shift operators, under most circumstances, can gage closely the grade of the mill products. However, there are times when the physical nature of the ore is radically different from normal. Under these conditions visual inspection is of no value, and at such times final ilmenite as low as 43 pct TiO, has been produced and shipped before the assay results have been received. The specific gravity method of assaying for TiO, has been attempted to eliminate the shipping of ilmenite below normal grade as well as to help control day to day and hour to hour mill production. Table I shows the minerals found in the MacIntyre ore along with their average weight proportions and specific gravities. The first two products considered for the specific gravity method were fine and coarse table concentrates. It was reasoned that these products were essentially ilmenite with the higher specific gravity gangue minerals. Since they were always produced the same way, and the desired grade of TiO, was always constant, the specific gravity of these materials would increase or decrease as the amount of ilmenite increased or decreased. Thus for table concentrates which assayed 40 pct TiOz a constant gravity would invariably be obtained, and as the TiO, value changed the specific gravity would change in direct proportion. The third product considered was Wetherill ilmenite. It was assumed that a desired grade of 44.7 pct Ti02 would also always contain the same amount and type of gangue minerals along with the ilmenite, and thus would always have the same specific gravity. As the TiO, value of the ilmenite concentrate changed so would its specific gravity. Dr. Kenneth Vincent, chief metallurgist of the Baroid Division of National Lead Co. at Magnet Grove, Ark., ran specific gravity tests on 17 samples of the desired products. The lowest specific gravity reading assayed the lowest in TiO, and as the specific gravity increased the trend was for the TiO, assay to increase, see Fig. 1. Since these results warranted further investigation, a 500-g capacity Torsion balance and 250 ml Le Chatelier specific gravity bottles were obtained. Shift samples of fine table concentrate, coarse table concentrate, and final ilmenite were tested. Each sample was split and 85 g weighed on the Torsion balance. The Le Chatelier bottle was filled with water to a zero mark. To avoid wetting the neck of the bottle it was found necessary to do this

Jan 1, 1953

By Alan Stanley

THE Maclntyre Development of National Lead Co. is located at Tahawus, N. Y., in the heart of the Adirondack Mountains. Operations involve the mining and concentrating of a titaniferous iron ore to produce ilmenite and magnetite concentrates. A general description of the operation and metallurgy has been given by Frank R. Milliken.1 Pigment plant production demands that the MacIntyre mill produce a 44.7 pct. TiO2 ilmenite concentrate. To achieve the required ilmenite grade and tonnage it is important that the table concentrate grade be closely controlled. Unfortunately, however, the titaniferous orebody which feeds the Maclntyre mill is not uniform. Ore dressing characteristics vary from one end of the orebody to the other, and from one level to the next.. The changeable nature of the mill feed precludes a single adjustment of the equipment for long periods of time. Thus the operators must constantly watch the equipment to insure a uniform concentrate from the fine and coarse tables and Wetherills, or dry magnetic separators. Chemical assaying of mill products requires about 4 hr from the time the sample is taken until assay results are obtained, and this is available only on a two-shift basis. The ore may change rapidly, even several times during a shift, so that assay results lose most of their control value by the time they are reported to the mill operating crew. Members of the crew have therefore tried to evaluate the table and Wetherill concentrate by visual inspection, since through long experience the shift operators, under most circumstances, can gage closely the grade of the mill products. However, there are times when the, physical nature of the ore is radically different from normal. Under these conditions visual inspection is of no value, and at such times final ilmenite as low as 43 pct TiO2 has been produced and shipped before the assay results have been received. The specific gravity method of assaying for TiO2 has been attempted to eliminate the shipping of ilmenite below normal grade as well as to help control day to day and hour to hour mill production. Table I shows the minerals found in the Maclntyre ore along with their average weight proportions and specific gravities. The first two products considered for the specific gravity method were fine and coarse table concentrates. It was reasoned that these products were essentially ilmenite with the higher specific gravity gangue minerals. Since they were always produced the same way, and the desired grade of TiO2 was always constant, the specific gravity of these materials would increase or decrease as the amount of ilmenite increased or decreased. Thus for table concentrates which assayed 40 pct TiO2 a constant gravity would invariably be obtained, and as the TiO2 value changed the specific gravity would change in direct proportion. The third product considered was Wetherill ilmenite. It was assumed that a desired grade of 44.7 pct TiO2 would also always contain the same amount and type of gangue minerals along with the ilmenite, and thus would always have the same specific gravity. As the TiO2 value of the ilmenite concentrate changed so would its specific gravity. Dr. Kenneth Vincent, chief metallurgist of the Baroid Division of National Lead Co. at Magnet Grove, Ark., ran specific gravity tests on 17 samples of the desired products. The lowest specific gravity reading assayed the lowest in TiO2 and as the specific gravity increased the trend was for the TiO2 assay to increase, see Fig. 1. Since these results warranted further investigation, a 500-g capacity Torsion balance and 250 ml Le Chatelier specific gravity bottles were obtained. [ ] Shift samples of fine table concentrate, coarse table concentrate, and final ilmenite were tested. Each sample was split and 85 g weighed on the Torsion balance. The Le Chatelier bottle was filled with water to a zero mark. To avoid wetting the neck of the bottle it was found necessary to do this

Jan 1, 1952

By N. A. Tiner, Saara Asunmaa

The early stages of nucleation of vacuunz-deposited gold coatings on electropolished surfaces of pure nickel and binary alloys of Ni-A1 and Ni-Ti have been studied, employing carefully controlled temperature and vacuum conditions. The preferential nucleation of gold on slip-plane edges on the crystal surfaces gave rise to a very pronounced decoration effect which was used in studying the morphology of the pain boundaries, etch pits, and slip planes on crystal faces. Characteristic surface patterns were observed with local dimensional variations. Most pronounced geometric patterns were ohserved in the pain boundaries of nickel and on the crystal faces of Ni-A1 alloy. The nucleation behauior of gold indicates contamination on the Ni-T1 alloy and the getter properties of titanium are presented as a tentative interpretation for the detected contamination. The markings and imperfections on cleavage surfaces of crystals have long been observed by optical microscopy.1,2 Surface-replica techniques are also used to detect the smallest steps and structural details on crystal surfaces by electron microscopy. Recently, Bassett3-5 and Sella, Conjeaud, and Trillat 6 have shown that, when gold is deposited onto a rocksalt cleavage surface, there is preferential nucleation at steps and slip-plane edges on the crystal surface. This gives rise to a very pronounced decoration effect which is invaluable for revealing the lattice steps on a cleavage surface. According to Bassett,3 gold atoms arriving during vacuum evaporation at the crystal surface have a certain mobility on the surface after arrival, particularly at elevated temperature. If a significant

Jan 1, 1964

By J. R. Long, T. R. Graham, R. S. Dean

FOLLOWING the development of elec¬trolytic manganese production by the Bureau of Mines, an extensive program was planned to study the character of this high-purity product and its possible utilization in various alloy combinations. Previous work reported in the literature concerning alloys containing substantial amounts of manganese dealt largely with material prepared from relatively impure grades of the metal, and in many instances the impurities thus introduced did not permit true evaluation of manganese as an alloying element. One phase of the Bureau's program included a general review of the system and the establishment of the physical properties of copper-manganese-zinc alloys, using electrolytic manganese, and with particular emphasis directed to com¬positions within the alpha solid solution area. A number of reports of the work on alloys in this system, giving specific data concerning the equilibrium system and some of its alloys, have already been published. One study1 established the alpha solid solution area at various temperature levels and composition ranges up to 50 pct manganese. Other investigation reports presented the properties of selected alloys; namely, a 65 pct copper, 10 pct manganese, 25 pct zinc alloys' a sensibly white manganese brass composed of 70 pct copper, 20 pct manganese, 10 pct zinc,3 and a series of alloys with a constant copper content of 60 pct and 5 to 25 pct manganese, balance zinc.4 In these reports tensile properties as influenced by cold-working and subsequent annealing were given in detail. Additional data are now available on other alloys of the alpha region up to 50 pct manganese, and these, together with previously published information, are sufficiently complete to establish the relationship between properties and composition for this portion of the ternary system. The present report is a summary of the tensile properties of wrought alloys in the form of sheet and rod stock. The summary is necessarily limited to data for only one condition of cold-work and a single annealing temperature, since a complete exposition of all the data available would be too extensive for this presentation. Nevertheless, it is possible to make a reasonable approximation of the tensile properties in other conditions of cold-working and annealing by a correlation of the data previously presented on specific alloys and the data given here.

Jan 1, 1947

By T. R. Graham, R. S. Dean. J. R. Long

Following the development of electrolytic manganese production by the Bureau of Mines, an extensive program was planned to study the character of this high-purity product and its possible utilization in various alloy combinations. Previous work reported in the literature concerning alloys containing substantial amounts of manganese dealt largely with material prepared from relatively impure grades of the metal, and in many instances the impurities thus introduced did not permit true evaluation of manganese as an alloying element. One phase of the Bureau's program included a general review of the system and the establishment of the physical properties of copper-manganese-zinc alloys, using electrolytic manganese, and with particular emphasis directed to compositions within the alpha solid solution area. A number of reports of the work on alloys in this system, giving specific data concerning the equilibrium system and some of its alloys, have already been published. One study' established the alpha solid solution area at various temperature levels and composition ranges up to 50 pct manganese. Other investigation reports presented the properties of selected alloys; namely, a 65 pct copper, I0 pct manganese, 25 pct zinc alloys;1 a sensibly white manganese brass composed of 70 pct copper, 20 pct manganese, 10 pct zinc,3 and a series of alloys with a constant copper content of 60 pct and 5 to 25 pct manganese, balance zinc.4 In these reports tensile properties as influenced by cold-working and subsequent annealing were given in detail. Additional data are now available on other alloys of the alpha region up to 50 pct manganese, and these, together with previously published information, are sufficiently complete to establish the relationship between properties and composition for this portion of the ternary system. The present report is a summary of the tensile properties of wrought alloys in the form of sheet and rod stock. The summary is necessarily limited to data for only one condition of cold-work and a single annealing temperature, since a complete exposition of all the data available would be too extensive for this presentation. Nevertheless, it is possible to make a reasonable approximation of the tensile properties in other conditions of cold-worki"g and annealing by a correlation of the data previously presented on specific alloys and the data given here.

Jan 1, 1947

By R. S. Dean. J. R. Long, T. R. Graham

Following the development of electrolytic manganese production by the Bureau of Mines, an extensive program was planned to study the character of this high-purity product and its possible utilization in various alloy combinations. Previous work reported in the literature concerning alloys containing substantial amounts of manganese dealt largely with material prepared from relatively impure grades of the metal, and in many instances the impurities thus introduced did not permit true evaluation of manganese as an alloying element. One phase of the Bureau's program included a general review of the system and the establishment of the physical properties of copper-manganese-zinc alloys, using electrolytic manganese, and with particular emphasis directed to compositions within the alpha solid solution area. A number of reports of the work on alloys in this system, giving specific data concerning the equilibrium system and some of its alloys, have already been published. One study' established the alpha solid solution area at various temperature levels and composition ranges up to 50 pct manganese. Other investigation reports presented the properties of selected alloys; namely, a 65 pct copper, I0 pct manganese, 25 pct zinc alloys;1 a sensibly white manganese brass composed of 70 pct copper, 20 pct manganese, 10 pct zinc,3 and a series of alloys with a constant copper content of 60 pct and 5 to 25 pct manganese, balance zinc.4 In these reports tensile properties as influenced by cold-working and subsequent annealing were given in detail. Additional data are now available on other alloys of the alpha region up to 50 pct manganese, and these, together with previously published information, are sufficiently complete to establish the relationship between properties and composition for this portion of the ternary system. The present report is a summary of the tensile properties of wrought alloys in the form of sheet and rod stock. The summary is necessarily limited to data for only one condition of cold-work and a single annealing temperature, since a complete exposition of all the data available would be too extensive for this presentation. Nevertheless, it is possible to make a reasonable approximation of the tensile properties in other conditions of cold-worki"g and annealing by a correlation of the data previously presented on specific alloys and the data given here.

Jan 1, 1947

By N. A. Gokcen, M. N. Dastur

In metallurgical process industries a knowledge of true melting and casting temperatures is very essential for increasing the operating efficiency as well as improving the quality of the finished product. Optical pyrometers are widely used for the purpose because of their cheapness and ease of operation. It is an unfortunate fact, however, that this mode of measuring temperature entails a source of severe error inasmuch as with all non-black bodies, the temperature observed is always below the true temperature owing to deficient emissive power. Hence, the need for emissivity correction arises. In 1913 Bidwell1 obtained emissivity values of 0.36-0.48 for a temperature range of 1520-1800°C. He measured the true temperature of molten iron by sighting into a carbon cavity immersed in the iron under an atmosphere of hydrogen. In 1914 Burgess2 determined the emissivity of a smooth surface of liquid iron free from oxide to be 0.37 under an atmosphere of hydrogen. He claimed to have attained an accuracy of within 5°C at 1500°C with an optical pyrometer using monochromatic light. He reported that no difference appeared to exist between the emissivities of pure iron and of steels containing considerable percentages of carbon, nickel or manganese; nor was there any appreciable variation of emissivity with temperature from 1530 to 1571°C. Wensel and Roeser3 found an elnissivity value of 0.4 for temperatures above 1375°C for cast iron. The average emissivity value for carbon steels reported by Leiber,4 odd,5 Hase6 and Umino7 range from 0.4 to 0.45. Knowles and Sarjant8 made an extensive study of emissivity of molten iron and steel over a wide range of workshop and laboratory conditions. Observations of true temperature were made with immersion thermocouples, and correlated with apparent temperatures indicated by optical pyrorneter readings taken on the pouring stream as it passed over the lip of the crucible. The emissivity of Armco iron was shown to be of the order of 0.4, rising slightly with increasing temperature. But for plain carbon steels containing up to 1.0 pct carbon the emissivity was shown to fall slightly with increasing temperatures. The results of their investigation are in agreement with those of Guthmann.9 Naeser,10 Spencer," Todd5 and Hase6 in regard to the relation between emissivity and temperature for plain carbon steels. However, Goller12 has found a rise of emissivity with increasing temperature for the same steels. Results of several investigations are given in Fig 1. Measurement of True and Apparent Temperatures The necessity for an accurate optical temperature scale for liquid iron in studies of gas-metal equilibria led to this investigation. Experimental measurements were carried out in the induction furnace used by Dastur and Chipman13 in their studies of the reaction of hydrogen with oxygen in liquid iron. The furnace as modified for this work is shown in Fig 2. The atmosphere of the furnace was a mixture of purified argon with hydrogen containing a small controlled amount of water vapor. Gases were preheated by means of a platinum-10 pct rhodium resistance coil. The stream of hydrogen sweeping across the surface of niolten iron vir-

Jan 1, 1950

THE preceding chapter has recorded the initiation of mineral industry education during the period 1890-1910 in numerous institutions that had not previously offered it. It should also be emphasized that in many institutions where instruction had begun before 1890, as recorded in earlier chapters, but had not yet become firmly established, this period was one of marked growth and development. This was not universally true, however, for at the Universities of Pennsylvania, Michigan, Illinois, Wisconsin, Washington (St. Louis), Iowa, Vanderbilt and Tennessee, and at the Polytechnic College of Pennsylvania, mineral industry instruction was being dropped during this period, instead of gaining in strength. It is necessary to emphasize this, because writers on the subject have not infrequently attempted to make a much too simple correlation between mineral discovery or production and the intensity of student interest in mineral industry curricula. It would naturally be true that periods of large mineral production would, in general, coincide with cycles of business prosperity, and the latter are conducive to starting new ventures, educational as well as business. It should be equally evident that opportunities for business and professional success might, in such periods, appear to increase at a more rapid rate in industries other than mineral, or in the utilization of minerals rather than in their production. The author has not been able to perceive any simple and clear relation between interest in mineral industry education and mineral discovery, production, and utilization, or general business prosperity. On the contrary, the more the problem is studied the more complex the factors involved in it appear to be. In a later chapter an attempt will be made to analyze them in more detail

Jan 1, 1941

By V. F. Marsters

Peru has produced petroleum since the early seventies, the first work being in the Zorritos field, in the Province of Tumbes, adjoining Ecuador. In the early nineties, the Negritos field, in the Department of Piura, came into prominence, and by 1905 had attained an annual production of 335,160 bbl. The early development of the field was under the general direction of the London & Pacific Petroleum Co., but it is now handled by the International Petroleum Co. In 1900 and 1901, the Lobitos field became the scene of marked activity. In 1905, its total production amounted to 75,000 bbl.; it has continued to increase as has Negritos. From 1897 to 1902, there was prospecting in the region of La Brieta (or Fernandez), on the Mancora River, about 25 to 30 km. from the coast. Small production of a heavy oil was obtained from three different sands. So far as the author knows, no work has been done in that locality since 1902. There are thus four distinct fields in the north endof the Peruvian coastal plain. The, remaining productive locality of Peru is the Pirin or Pusi field, at the northwest end of Lake Titicaca, Department of Puno, in southern Peru. The first prospecting near Pusi was done by Brown Brothers, of Los Angeles, Calif., who obtained modest production about 1906; according to reports, activities ceased about 1914 or 1915. The maximum annual production was obtained about 1908, estimated at 76,000 barrels. Peru possesses two distinct geographic provinces in which we may look for the development of a larger oil industry; namely, the coastal plain province, and the inter-Andean plains.

Jan 7, 1922

James Gayley, Braddock, Pa. (communication to the Secretary) : Mr. Potter has made reference to our practice at the Edgar Thomson works in the direction of increasing the life of the lining, and mentions the product of one of our furnaces as having reached a total of 370,000 tons. It may be interesting to know that this furnace has been put out of blast with a record of 452,685 tons, after a run of three years and nine months. A companion-furnace to this will produce, hefore the present year is ended, half a million tons. As Mr. Potter has quite correctly designated this as " the newest problem in furnace-practice," a description of the construction of this furnace lining may be Welcome to members. The bricks used in the lining are 9 and 134 inches long, with the requisite quantity of straight and key-shapes to turn the circle. There bricks are well suited for enclosing the numerous bosh-plates used for cooling. The bosh-plates (the efficient fortress of the lining) extend from the top of the tuyere arch to the mantel, and are inserted in rows, 18 inches to 2 feet apart. These form a perfect defence against encroachment on the bosh-lining, and leave the bosh at the end of the blast of the same thickness as at the beginning. The protection afforded by these bosh plates is the principal cause of the increased duration of the furnace-lining. But it must be noted that the shape and material of the plate are essential elements. The most serviceable plate is that made of bronze or copper. We have tried every form of iron plates without obtaining satisfactory results. These were replaced with bronze plates, built into the lining, which gave excellent results so long as they did not leak; but when this occurred, as it did in time, the water was shut off, and, since the plates could only be removed with difficulty, they were allowed to burn off. This permitted encroachment on the bosh-walls, which thus became enlarged beyond the limit required for economical practice. With the introduction of the removable plate, made tapering on the sides, with plain surfaced top and bottom, these troubles have

Jan 1, 1895

By J. W. Cloud

years ago upon the effect of having the rails always rolled in the same direction, and also of having them rolled backwards and forwards, and showed that under the latter course there were of necesshy weak spots somewhere near the centre of the rail, yet in all this discussion the methods of rolling have been passed by almost in silence. Mr.. Sandberg in his paper mentions the idea of using a regietering dynamometer attached to the punching machines, and of det.erminit~g the quality of the metal by the resistance which is shown. I think the' first idea of this kind was published by Professor Langley, then of Pittsburgh, who, while making some investigations for Mesrs. Miller, Metcalf and Parkin, announceti as tile result of a series of dynamometric experiments that abrasive resistance was the term which should be wed in regard to steels of different wearing qualities. I have had extremely delicate dynamometers attached to the instruments of precision with which I am making the iuvestigation on the fatigue of metals, and hope soon to communicate the results of the iovegtigation- made with them to the Institute. I wish again to call attention to the fact that we are wing the words " hardener " and " hardness " without any real idea of the meaning of these words. When we say hard and soft, as we have hen constantly doing during this discussion, is it quite sure that every one has exactly the same meaning in his mind ? Certainly, when hard is used in distinction from soft*, we mean not the capacity of wear, but the capacity of resistance to peuetration, to fracture, or some other resistance, and do not always meau the capacity of resistance to abrasion or crushing, which the discussion would sometimes seem to imply were the only qualitiw requisite to constitute a god rail. J. W. Cloud, Altoona, Pa. : I would call the attention of the Institute to the title of Dr. Dudley's interesting and valuable paper, —" The Wearing Capacity of Steel Rails in relation to their Chemical Composition and Physical Properties." Here are two separate and distinct questions: lst, The wearing capacity of steel rails in relation to their chemical content; and 2d, the wearing capacity of steel rails in relation to their physical properties. The discussion has been almost exclusively confined to the former question, on which there may be many differences of opinion in matters of detail without greatig affecting the result. The latter

Jan 1, 1881

By D. M. Bondurant

Auger mining-extraction of coal with large diameter augers is proving profitable in recovering coal left after stripping has ceased to be economical. Its many advantages-low initial cost of equipment, low operating cost, low power demand, adaptability to selective mining, simplicity of operation, etc.-have excited the interest of some in the industry in its possibilities for underground operation.

Jan 5, 1951