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By P. H. Bohart

THe answer to the title question will be found by considering the ultimate influence of the petroleum engineers on industry and by considering the tools with which petroleum engineers must be equipped. Some 2000 to 3000 petroleum engineers are being absorbed by the industry yearly, indicating the magnitude of influence which they may exert on the industry. The petroleum industry is a highly technical one and it is inevitable that management be entrusted more and more to executives with technical training. The industry, therefore, expects the petroleum engineering schools to provide a broad basic training and a social and economic orientation which goes beyond merely supplying the minimum technical qualifications necessary to discharge responsibilities for a particular job. Because of the many branches of industry, emphasis must be placed on the Student's being trained in fundamentals, as well as grounded in other engineering branches, such as mechanical, civil and electrical engineering. The petroleum engineering graduate must know how to outline and organize the material for an engineering report and should be thoroughly grounded in English, both written and spoken. Even to the end that a five-year course may be required, they should receive instructions in auxiliary cultural and social science courses, industrial relations, and public speaking. Training in the method of approach to an engineering problem is something in which industry is deeply interested. A standard of ethics, a desire to arrive at the truth, and leadership training should be stressed. Introduction The basis of an an to any ques- tion concerning the petroleum engineering schools' responsibility to the industry will be found by considering the ultimate influence of the petroleum engineers on the industry and by considering also the tools with which petroleum engineers must be equipped in order to achieve success and happiness in the role in which their training, individual talents and choice of a profession ultimately will cast them. The problem must always be considered as it relates to a large group and not as it relates to a particular individual possessing strong natural talents and destined, by virtue of them, to pursue a certain course. The question implies that petroleum engineering schools have a responsibility, and indeed they do, not only to the industry but also to the students and even to the public. Because the responsibility is concentrated in a relatively few schools whose graduates are absorbed largely by the one industry, the responsibility is more apparent and the effect of failure to discharge the responsibility fully is more serious than the effect of similar failure on the part of schools supplying a smaller portion of the industry's intake of engineering graduates. This fact is especially true with respect to an industry such as the petroleum industry whose ratio of technical to nontechnical employees is relatively high and is increasing.

Jan 1, 1948

By P. H. Bohart

THe answer to the title question will be found by considering the ultimate influence of the petroleum engineers on industry and by considering the tools with which petroleum engineers must be equipped. Some 2000 to 3000 petroleum engineers are being absorbed by the industry yearly, indicating the magnitude of influence which they may exert on the industry. The petroleum industry is a highly technical one and it is inevitable that management be entrusted more and more to executives with technical training. The industry, therefore, expects the petroleum engineering schools to provide a broad basic training and a social and economic orientation which goes beyond merely supplying the minimum technical qualifications necessary to discharge responsibilities for a particular job. Because of the many branches of industry, emphasis must be placed on the Student's being trained in fundamentals, as well as grounded in other engineering branches, such as mechanical, civil and electrical engineering. The petroleum engineering graduate must know how to outline and organize the material for an engineering report and should be thoroughly grounded in English, both written and spoken. Even to the end that a five-year course may be required, they should receive instructions in auxiliary cultural and social science courses, industrial relations, and public speaking. Training in the method of approach to an engineering problem is something in which industry is deeply interested. A standard of ethics, a desire to arrive at the truth, and leadership training should be stressed. Introduction The basis of an an to any ques- tion concerning the petroleum engineering schools' responsibility to the industry will be found by considering the ultimate influence of the petroleum engineers on the industry and by considering also the tools with which petroleum engineers must be equipped in order to achieve success and happiness in the role in which their training, individual talents and choice of a profession ultimately will cast them. The problem must always be considered as it relates to a large group and not as it relates to a particular individual possessing strong natural talents and destined, by virtue of them, to pursue a certain course. The question implies that petroleum engineering schools have a responsibility, and indeed they do, not only to the industry but also to the students and even to the public. Because the responsibility is concentrated in a relatively few schools whose graduates are absorbed largely by the one industry, the responsibility is more apparent and the effect of failure to discharge the responsibility fully is more serious than the effect of similar failure on the part of schools supplying a smaller portion of the industry's intake of engineering graduates. This fact is especially true with respect to an industry such as the petroleum industry whose ratio of technical to nontechnical employees is relatively high and is increasing.

Jan 1, 1948

By C. O. Brawner

The advent of larger drilling, excavation, and milling equipment is resulting in a tremendous increase in the scale and annual tonnage of open pit mining. At the present time, open pits up to 3000 ft. deep, and tailings dams and waste dumps up to 600 ft. high are being planned. One of the major problems that projects of this magnitude create is stability. Stability at open pit mining developments must be assessed for tailings dams, waste dumps, and open pit slopes in overburden soil and in rock. Soil mechanics principles are used to assess the stability for the first three. This science was developed by Dr. Karl Terzaghi in the 1920’s, and since that time the theories and principles have been tested and evaluated. This experience has resulted in the development of sound theoretical concepts, workable sampling and testing techniques, and accurate methods of analysis. Typical problems that can be analyzed include: -bearing capacity of soil under dams and waste dumps. - amount of seepage under and through dams. - stability of slopes and determination of safe slope angles for tailings dams, waste dumps, and open pits. - influence of earthquakes on stability. - influence and cost of different excavation and construction techniques. To assist in comparing engineering experience, an international soil classification system has been developed and used for several decades. In addition, many excellent text books are available outlining soil mechanics principles and techniques. A high degree of technology exists in soil mechanics. This, the mining engineer cannot afford to ignore. If soil mechanics principles had been applied, many major failures involving tailings, tailings dams, or waste dumps, such as those at Aberfan, Mufulira, Luanshya, and El Cobre would not have occurred. Tailings dams are planned in Canada that will be up to 600 ft. high. Construction procedures used in the past have paid little attention to the compaction of the shell material or to the influence of earthquakes on stability. This neglect has led to failures. While failures in low dams may not be too serious, for high dams such failures could have catastrophic results. Another major area of concern is the stability of rock slopes. From the standpoint of long

Jan 1, 1971

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member, technical graduate, aged 40, member Institute of Mining and Metallurgy 16 years, with varied experience. Actual underground work,. foreman, surveying, milling, mine examination, superintendent, manager, and other positions of trust. Several years' European practice. Familiar with flotation process. Desires responsible position. References furnished. No. 172. Member, aged 40, graduate Massachusetts Institute of Technology. Twenty years' successful experience as blast-furnace superintendent (merchant and steel works), covering operating, remodeling and? building. General superintendent and general manager of proposition comprising blast furnaces, coal and coke, and iron-ore operation, etc. Good organizer and handler of men. Desires position in above line anywhere. No. 173. Member, technical graduate, aged 43, with 20 years' experience in management of gold, silver, and copper properties and also coal and smelting properties in United States, Canada and Mexico. Owing to illness compelled to resign. Now open for engagement. No. 174. Member, technical graduate, with many years' experience with large smelting and refining companies as chemist, metallurgist, and superintendent desires position. No. 175.

Jan 1, 1915

By R. H. Jacoby, M. J. Rzasa

Experimental equilibrium vaporization ratios were obtained for nitrogen, methane, carbon dioxide, ethane, and hydrogen sulfide in natural gas-condensate systems. Two different overall mixture compositions were investigated over the pressure range 500 to 4,000 psia at 100°, 150°, and 200 °F. Partial phase diagrams of the mixtures were obtained; one of these showed a critical point at 204°F and 3,875 psia. These and earlier data' were compared with the Kellogg correlation' at! 100°F and 1,000 psia. INTRODUCTION The authors' have presented equilibrium vaporization ratios for nitrogen, methane, carbon dioxide, ethane, and hydrogen sulfide in complex mixtures, such as natural gas-crude oil and natural gas-absorber oil. Since mixtures of the natural gas-condensate type also occur widely in petroleum reservoirs and often contain the non-hydrocarbons mentioned, it would be useful to have appropriate K data for calculating equilibrium vaporization conditions. Roland, Smith, and Kave-ler' obtained K's for methane and the light hydrocarbons in gas-condensate mixtures; and Poettmann and Katz3 obtained K's for carbon dioxide in a gas-condensate system. The data presented in this paper extend this coverage to include K's for nitrogen and hydrogen sulfide and phase diagrams for the experimental mixtures. EXPERIMENTAL WORK The equipment and experimental procedure was essentially as described previously, except for analysis of the vapor samples. The vapor sample bombs were filled at the pressure and temperature of the run. Immediately after sampling, a portion of this sample was flushed from the bomb into a 650 cc glass bulb, filling it to near atmospheric pressure. The sample in the glass bulb was then analyzed by the mass spectrometer. Some checks were made on this analytical procedure to find the accuracy of measurement of the C + content of the vapor samples. The modifications tried were complete fractionation of the vapor sample and the use of several liquids (depropanized condensate and retrograde liquid from several vapor samples) as calibrating materials for the mass spectrometer. The results obtained from these various checks differed by about 10 per cent relative and this is believed to be the order of accuracy of the vapor C+ concentrations.

Jan 1, 1953

By J. A. Clum, R. W. Heins, T. D. Tiemann

The use of Na-montmorillonite clay binders (Western Bentonite) in the pelletizing of iron ore concentrates is well established as is the idea that alternative binders must be found. 1-6 This note summarizes work done7 in evaluating a Wisconsin montmorillonite clay binder. The clay occurs in irregualr beds overlying the Prairie du Chien Dolomite and the St. Peters Sandstone near Hersey, St. Croix County.

Jan 1, 1978

By John S. Alexander

The typical block coal of the Brazil (Indiana) District differs in chemical composition but little from the coking coals of Western Pennsylvania. The physical difference, however, is quite marked; the latter has a cuboid structure made up of bituminous particles lying against each other, so that under the action of heat fusion throughout the mass readily takes place, while block coal is formed of alternate layers of rich bituminous matter and a charcoal-like substance, which is not only very slow of combustion, but so retards the transmission of heat that agglutination is prevented, and the coal burns away layer by layer, retaining its form until consumed. This property permits the use of raw block coal in the furnace but theo-

By Morris Cohen

This paper deals with the calculation of the composition of the infinitesimal trace of alloy that transfers from the liquid to the solid state at each temperature during the equilibrium solidification of a binary solid solution, and which thereby enables the compositions of the coexisting liquid and solid phases to follow along the liquidus and solidus lines respectively during the cooling. A general expression for the composition (S) of the liquid-to-solid transfer at each temperature has been derived S - ZLXL(XL - P) + Zsxs(P - XS) ZL(xL - P) + Zs(P - XS) where ZL and Zs are the slopes of the liquidus and solidus lines at the given temperature, XL and xs are the composi-tions of the stable liquid and solid phases at the same temperature, and P is the composition of the alloy under considera-tion. The S equation is valid for the process of equilibrium heating as well as cooling, and may be applied to vapor-to-liquid, vapor-to-solid, liquid-to-liquid, and solid-to-solid transfers if the corresponding equilibrium diagrams are known.

Jan 1, 1940

[ ] TUNNELS TO BINS. Originally designed for tunnel work, the strong lightweight liner plates used to construct this 30-ft diameter, 31-ft high, aggregate storage bin have several advantages. Bins and conveyor to tunnels can be quickly erected in any season, for permanent service, or to be salvaged and reused. Armco Steel Corp. (16) ROLLER CHAIN: Engineering Data Book No. 2457 published by Link-Belt Co. is a comprehensive 148-page volume on roller chain and its application. Detailed engineering information covers installation, maintenance and lubrication of chains for drives, conveyors, and sprocket wheels. The book covers selection of drives to meet both standard and special installations. (17) LABORATORIES: The Fisher Scientific Co's. line of 21 basic units of standardized steel laboratory furniture is described in catalog no. 25. The Unitized line was designed to combine the advantages of custom installation with the convenience of selection, delivery and continued flexibility that goes with ready-made units. (18) PUMPS: Two similar, but functionally different types of vertical centrifugal wet-pit pumps; a heavy duty bilge pump for handling solids-free liquids and drainage; and a screenless sewage ejector, constructed to handle sewage and solids carrying liquid; are illustrated in a bulletin from Yeomans Bros. Co.

Jan 1, 1952

By I. J. Corrans

Wet high-intensity magnetic separation (WHIMS) has been successfully applied to the recovery of gold and uranium from the residues of Witwatersrand ores. Good overall recoveries have been achieved for particles as small as 12µ, and finer particles of uranium minerals are recovered when present as inclusions. The best results were obtained with a matrix of soft-iron balls 6 mm in diameter. However, pilot-plant tests drew attention to a major defect of the machine: the matrix could be blocked by wood chips and ferromagnetic particles. This problem was overcome by the incorporation of a modification that allows the balls to be discharged from the rotating annulus. Two full-scale units that incorporate the modification have been installed.

Jan 1, 1980

By Thomas M. Plouf

Flotation, as we know it today, is a physiochemical method of concentrating finely ground ores. The process involves chemical treatment of an ore pulp to create conditions favorable for the attachment of certain mineral particles to air bubbles which are carried to the surface of the ore pulp for removal. Frother reagents, combined with air and the agitation mechanism, produce the effective bubbles in a flotation cell. A method of analysis is presented to evaluate the effect of frother reductions and additions on a bank of flotation cells, and to economically determine if and to what extent frother reductions and additions are justified. Comparative evaluations of different frother systems, as well as the amount of frother used in a given flotation machine, cannot be made on the frother cost alone. An indepth study must be made to evaluate any given frother as applied to a particular ore body. The recovery of a given mineral is as dependent on the amount of frother as on the type of frother used. An actual case study follows in which the amount of frother required by two different flotation machines was used to make a decision as to which unit performed more efficiently based on costs. This same method may be used to evaluate new frothers as well as to determine if a larger frother addition is advisable.

Jan 11, 1975

By J. H. Swislzer

TWO-LIQUID miscibility gaps have been found to exist in both the CaO-SiO, system above 1705 and the Cr,03 system above 2200"c. Glasser and 0sborn3 studied the extension of these miscibility gaps into the Ca0-Si0,-Crz03 ternary system and reported that the two-liquid region is not present at temperatures below the monotectic temperature of 1705°C in the CaO-SiO, system. The present authors, in connection with other work on surface-tension measurements and foam stabilities in the same ternary system,4 observed that the miscibility gap exists at temperatures as low as 1600°C. A brief experimental study was devoted to deter- mining tie-line positions in the two-phase region. The technique used was to obtain a separation of phases at 1600°C, then to quench-in the high-temperature phases and obtain a chemical analysis of each phase. It was necessary to take special precautions in obtaining a phase separation because of a tendency toward emulsification of the two liquids. The procedure followed is described in the schematic drawing in Fig. 1. A small platinum crucible containing several pinholes on its sides was placed inside a larger platinum crucible. An excess of Crz03 was placed in the outer crucible, together with a prefused binary CaO-Si02 mixture, and the Cr203 was allowed to diffuse through the pinholes and saturate the same binary CaO-SiOl mixture in the smaller crucible. After equilibration at 1600°C, the inner crucible contained only the lighter liquid (liquid A) saturated with Cr203. The outer crucible contained layers of both liquids. Experimental data were obtained by analyzing the entire contents of the inner crucible and only the bottom layer of the larger crucible (liquid B). The upper layer of the outer crucible was not suitable for chemical-analysis purposes because dispersions of the second phase sometimes were found in the samples. The technique is described in more detail in Ref. 4. The same method was used by Grieveson and urkdoan' to study a miscibility gap in sulfate-ferrite melts, where the liquids were difficult to separate because of similarities in density. In addition to the phase-separation experiments, a few others were conducted to obtain information

Jan 1, 1964

By D. Harrington

EFFICIENT ventilation of metal mines consists in having such complete control of air currents that. there is always supplied at places where men work sufficient moving air to allow working at maximum capacity without injury to health; and in case of underground fire or of surface fire in the vicinity of mine openings, underground air currents may be quickly reversed if desired, or air may be sent into or excluded from any region and fire fumes confined to only part of the mine workings, instead of penetrating practically the entire mine. Health and safety of workers in mines as well as proper safeguarding and operating efficiency of mining properties are so intimately associated with proper ventilation of mines (both coal and metal) that they are inseparable, yet mine ventilation is only too frequently neglected, especially in metal mines. The metalliferous operator, generally not confronted with inflammable gas or explosive dust which so frequently force ventilation of coal mines, usually disregards air supply altogether except such as may be obtained from compressed air; and generally, even when attention is given to metal-mine ventilation, the air currents rarely are found where they are needed, namely, the working places, especially the working faces. After several years' study of miners' consumption, the writer is. convinced that long continued breathing of air impregnated with large quantities of any kind of finely divided dust, such as is found in a large number of the working places of our mines, will ultimately produce some respiratory disease, whether it be asthma, bronchitis, or phthisis; and the progress of these diseases is hastened. if there are also present high temperatures, high humidities, or harmful gases or if there is present (and allowed to remain to be breathed) large quantities of the finely divided dust when air temperatures are low, hence favorable to maximum performance of work with accompanied maximum breathing into the respiratory passages of the harmful material. It is generally accepted

Jan 2, 1922

The House Committee of the Engineering Societies Building has lent to he members of the three welfare committees a room on the ground floor of the building where they can carry on some of their war activities. Two sewing machines and two knitting machines are installed there and ladies are invited to sew for the Foreign War Relief Committee and knit for the Emergency Committee, which is working for the 27th Engineers, a special mining regiment. The Emergency Committee, Mrs. H. Norman Spicer, Chairman, reports the formation of a committed of 21 members. The organization meeting was held March 7, and plans were made for future activities as follows: A letter was read from Mr. Ingalls asking for 72 sweaters, 72 helmets, 66 pairs of wristlets as well as 772 pairs of socks, 272 being for immediate delivery. To meet this request it was decided to secure the helmets and wristlets from the Navy League, and to undertake the making of the sweaters and socks ourselves. Accordingly Mrs. H. N. Spicer and Mrs. J. H. Devereux were empowered to buy wool in sufficient quantities, and woven material for the 72 sweaters, sending the bills to Mr. Ingalls, who had guaranteed the money from the Engineering and Mining Journal. This was attended to promptly, and the materials were ready for distribution to the committee on March 13. After considerable difficulty, knitting machines for the socks were discovered and the agent came to demonstrate them. Mrs. Spicer gave one to the Committee and Mr. Ingalls has guaranteed the money to buy two when the manufacturers can deliver them. Up to April 6, 130 pairs of socks, machine and hand-knitted, have been handed in-also 68 sweaters, 80 helmets and 90 pairs of wristlets. It has been calculated that it needs five women knitting behind each man at the front to keep him continuously supplied with knitted garments.

Jan 5, 1918

By Joshua E. Clayton

THIS remarkable gold and silver bearing district is situated on the middle fork of Boise River, in Alturas County, Idaho Territory, about eighteen miles north of Rocky Bar, and sixty-five to seventy miles, as the crow flies, east of Boise City, the capital of the Territory. This district lies in the very heart of one of the most wild and mountainous regions of Idaho. For many miles in every direction nothing can be seen but bold granite mountains, with deep narrow gorges cutting into their sides in every direction, rendering them almost inaccessible except to the hardy mountaineer and adventurous prospector. The mountain sides are covered, in most part, by dense forests of pine, fir, and spruce timber. In every canon there are clear streams of pure running water that empty into the principal forks of Boise River. The only line of approach to this mountainous region at present is from the southwest, by way of Rocky Bar, the county seat of Alturas County, to which place there is a good wagon-road. From thence to Atlanta City, eighteen miles, the road, or pack-trail, passes over the high, steep range that separates the south and middle forks of Boise River. During severe winters this line of approach is closed up by deep snows for months at a time, thus leaving the district isolated, in the bosom of the grand old mountains. The geological formation is granite, of a coarse, friable texture, and in many places is traversed by numerous dikes of syenite, and three or four varieties of porphyry, which cut through the granite in easterly and westerly directions. The metal-bearing veins also have an easterly and westerly trend, but are occasionally intersected by the dikes. The largest number of the gold and silver lodes are confined to a

Jan 1, 1877

By Joshua E. Clayton

This remarkable gold and silver bearing district is situated on the middle fork of Boise River, in Alturas County, Idaho Territory, about eighteen miles north of Rocky Bar, and sixty-five to seventy miles, as the crow flies, east of Boise City, the capital of the Territory. This district lies in the very heart of one of the most wild and mountainous regions of Idaho. For many miles in every direction nothing can be seen but bold granite mountains, with deep narrow gorges cutting into their sides in every direction, rendering them almost inaccessible except to .the hardy mountaineer and adventurous prospector. The mountain sides are covered, in most part, by dense forests of pine, fir, and spruce timber. In every canon there are clear streams of pure running water that empty into the principal forks of Boise River. The only line of approach to this mountainous region at present is from the southwest, by way of Rocky Bar, the county seat of Alturas County, to which place there is a good wagon-road. From thence to Atlanta City, eighteen miles, the road, or pack-trail, passes over the high, steep range that separates the south and middle forks of Boise River. During severe winters this line of approach is closed up by deep snows for months at a time, thus leaving the district isolated, in the bosom of the grand old mountains. The geological formation is granite, of a coarse, friable texture, and in many places is traversed by numerous dikes of syenite, and three or four varieties of porphyry, which cut through the granite in easterly and westerly directions. The metal-bearing reins also have an easterly and westerly trend, bat are occasionally intersected by the dikes. The largest number of the gold and silver lodes are confined to a

By C. M. Means

CONSIDERING the hazard involved in mining operations, statistics show, that a very small percentage of accidents is chargeable to electricity. These accidents do represent quite a large percentage of those that are preventable and they are the direct result of the introduction, for purely economical reasons, of a dangerous element. The introduction of electricity in mines should decrease the hazard, and in no case should electricity be applied to the mechanical operation of equipment if by so doing the dangers incidental to mining are increased. The greater number of accidents are the result of persons coming in contact with exposed conductors at potentials varying from 250 to 500 volts direct current. The use of alternating current at higher potentials than these is quite common in large mines, but it is very rare that an accident happens from this source. This is explained by the fact that where these high voltages are warranted, proper precautions are taken, and the installations are directed by those who fully appreciate the dangers incidental to the work. Direct current is in much more general use than alternating current because of its adaptability to haulage locomotives and the low cost of installation in small operations. We are, however, coming to a more extended application of alternating current for the operation of mechanical devices used in connection with mining. Our underground direct-current wiring system is an evolution from the surface trolley and feeder systems. This is probably due to the fact that our earlier successful applications were electric locomotives, which required the use of a trolley wire. The trolley current has been almost banished from industrial establishments on the surface because of the hazard involved, yet we use it indiscriminately underground, where the dangers from accidental contact or fire are infinitely greater. This does not mean that the underground trolley systems should be eliminated, but it does imply the proper safeguarding of such equipment as is necessarily a part of the trolley systems.

Jan 4, 1914

By H. V. Churchill

There are two distinct methods of combating corrosive conditions. The first and most popular method is to choose a surface or material which will give adequate service under the specific and general conditions which are present. The second is a control or modification of the corrosive conditions to the end that metals and materials which would be attacked and corroded without such control or modification may be used. Under the first method of attack of the corrosion problem may be grouped such devices as the selection of metals or alloys which offer great resistance or the use of protective coatings such as paints, lacquers or metallic coatings. Such procedures are exceedingly useful. It is undoubtedly true that most of the problems of corrosion will be solved by recourse to this first method of attack. However, it must be remembered that there are many conditions in which metals are used where the choice of the particular metal to be used must depend upon other factors than corrosion behavior. Some of the factors which may govern the selection of metals for specific use are the physical and mechanical properties of the metals. But there is another factor which is of prime importance and that is relative price. It is the pressure of these factors of mechanical properties, physical characteristics, and relative price that has acted as the stimulus for the second methhod of combating corrosion. The producer and user of various metals is confronted with the fact that because of mechanical properties, physical characteristics, or price, the use of a particular metal is desirable even though the corrosion conditions are adverse to the use of the metal. In many cases, the successful use of the metal may be made even though it is impossible to protect the metal by coatings. This is rendered possible by control or modification of the corrosive media. Use of Sodium Silicate to Prevent Attack by Alkali Solutions This idea of controlling or modifying corrosive media is well illustrated by some recent experiences with aluminum. For a number of years collapsible tubes have been made of aluminum. Due to the ease with which aluminum is attacked by even mild alkalies, the use of such tubes

Jan 1, 1929

By H. V. Churchill

There are two distinct methods of combating corrosive conditions. The first and most popular method is to choose a surface or material which will give adequate service under the specific and general conditions which are present. The second is a control or modification of the corrosive conditions to the end that metals and materials which would be attacked and corroded without such control or modification may be used. Under the first method of attack of the corrosion problem may be grouped such devices as the selection of metals or alloys which offer great resistance or the use of protective coatings such as paints, lacquers or metallic coatings. Such procedures are exceedingly useful. It is undoubtedly true that most of the problems of corrosion will be solved by recourse to this first method of attack. However, it must be remembered that there are many conditions in which metals are used where the choice of the particular metal to be used must depend upon other factors than corrosion behavior. Some of the factors which may govern the selection of metals for specific use are the physical and mechanical properties of the metals. But there is another factor which is of prime importance and that is relative price. It is the pressure of these factors of mechanical properties, physical characteristics, and relative price that has acted as the stimulus for the second methhod of combating corrosion. The producer and user of various metals is confronted with the fact that because of mechanical properties, physical characteristics, or price, the use of a particular metal is desirable even though the corrosion conditions are adverse to the use of the metal. In many cases, the successful use of the metal may be made even though it is impossible to protect the metal by coatings. This is rendered possible by control or modification of the corrosive media. Use of Sodium Silicate to Prevent Attack by Alkali Solutions This idea of controlling or modifying corrosive media is well illustrated by some recent experiences with aluminum. For a number of years collapsible tubes have been made of aluminum. Due to the ease with which aluminum is attacked by even mild alkalies, the use of such tubes

Jan 1, 1929

Jan 1, 1932