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By K. Hanumantha Rao, T. C. Rao, M. Vanangamudi

The effects of important variables such as pulp density, feed size, furnace oil dosage, degree of agitation, and time of agglomeration on the yield and ash content of the agglomerates obtained from the oil agglomeration of coal fines have been studied in a laboratory batch agglomeration cell. Optimum conditions for maximum yield and throughput have been discussed. The furnace oil dosage and pulp density were found to have more influence on the yield and grade of the agglomerates than the degree of agitation and feed size in the ranges studied.

Jan 1, 1983

By Nicholas J. Grant, Olaf Troili, John Chipman

IN recent studies of the factors which affect the rate of desulphurization and its equilibrium, it became apparent that certain concurrent reactions were operative which had a significant effect on desulphurization. This is emphasized in the experiments of Hatch and Chipman1 and of Grant, Kalling, and Chipman' by the slow approach to a final state of equilibrium which is in marked contrast to the initial rapid transfer of sulphur from metal to slag. Since the removal of sulphur is of such profound importance in iron and steelmaking, it appeared necessary to investigate the reactions responsible for this behavior. It is now known that the presence of iron oxide in the slag interferes seriously with the principal reaction of blast-furnace desulphurization: CaO (slag) +-S + C - CaS (slag) + CO [l] The interfering reaction is most simply expressed as: CaS (slag) + 0 = CaO (slag) +-S 121 and a small concentration of oxygen (or FeO) is sufficient to hold a considerable amount of sulphur in the metal. It has been shown by Grant, Kalling, and Chipman2 that the addition of MnO to blast-furnace slag slows the removal of sulphur from the metal. This effect overshadows the contribution of MnO to basicity and is ascribed to its oxidizing power. It will be shown in this paper that SiO, also has sufficient oxidizing power to interfere with blastfurnace desulphurization. This is, of course, only one of its several effects. Primarily it is an acid and therefore reduces the concentration of excess lime. But when silicon is reduced to the metal the oxygen to which it was previously bonded becomes in part available for reaction 2. The proof of this statement is found in the following experiments. Experimental Procedure and Results Utilizing the same procedure and apparatus described by Grant, Kalling, and Chipman' five additional heats were made using slags IV and 11, the starting compositions of which were: slag IV—40 CaO, 10 MgO, 35 SiO,, 15 A1,0,; and slag 11—50 CaO, 10 MgO, 25 SiO,, 15 Al3O3. An important difference between these heats and those previously reported was that silicon to the extent of 1 to 4 pct was added to the present heats whereas the starting silicon content was formerly about 0.2 pct. Table I shows the slag and metal analyses for heats 82 to 87, and Table I1 shows the silicon addi- tions made to the charge. These additions are based on 400 g of metal and 400 g of slag. All heats had 1.65 400pct S charged before the cold slagadditions. The temperature was maintained at 1525°C. Rate of SiO, Reduction: Fig. 1 shows the silicon content of the metal in contact with slag IV at 1525°C as a function of time. Heat 70 from the work of Grant, afunctionKalling,of and Chipman is included as the lowest starting silicon. It will be noted that eeven with 4 pct Si in the starting metal, there is an increase in silicon content with time. Heat 84 is apparently approaching silicon equilibrium very slowly. Heats 70 and 82 with very much lower slowly.starting silicon show a more rapid initial rise in startingsilicon content but do not reach equilibrium during a long holding period. Fig. 2 shows 3 different initial silicon contents for Fig.2shows3differentheats 73 (from Grant, Kalling, and Chipman) 86 and 87, in contact with slag II, the most basic slag. Heat 73 is increasing in silicon with time, whereas heat 87 with an initial silicon content of 3.7 pct shows a decrease with time. Heat 86 shows a very close approach to equilibrium. The rate of transfer of silicon from slag to equilibrium.metal is very slow in all of those heats, even those which are initially far from equilibrium. ____

Jan 1, 1952

By F. Weinberg

In developing a mechanism for the solidification of metals from the melt, it has been proposed that solidification proceeds by the growth of platelets parallel to close packed planes. The evidence for this is based primarily on observations of decanted interfaces of lead1,2 and tin on which platelets 1 to 10 µ thick4 were observed. In recent observations of decanted eutectic alloys, 5,6 it was found that the eutectic structure on the decanted surface was markedly different than that of the bulk material, with the surface structure extending approximately 10 µ behind the interface.' This suggested that, at least for these experiments, a residual liquid layer 10 µ thick had been left on the decanted interface, which solidified subsequent to decanting. If a similar thickness of residual liquid was left on the decanted surfaces in the lead and tin observations referred to above, then it is questionable to what extent the observed platelets can be related to the solid-liquid interface before decanting. The purpose of the present investigation was to measure the thickness of the residual liquid layer on a decanted surface of tin, using relatively standard decanting procedures. The technique used was to add approximately 200 ppm of Tl204 (PI) to the melted portion of a high purity (99.999 pet) bar of tin, which was being progressively melted from one end, and then decant during melting. Since only the melt contained the radioactive tracer, the activity emanating from the decanted surface could be used as a measure of the thickness of the residual liquid layer. Progressive melting was carried out in the same fashion as single crystal growth, namely, in a horizontal graphite boat, in an argon atmosphere, using a moving furnace. The decanting was done in two ways; 1) removing the furnace and suddenly dropping the melt end of the boat, and 2) suddenly jerking the solid away from the liquid by the action of a falling weight (estimated peak acceleration 3 x 105 cm per sq sec), using a split graphite container. In all cases the melt was vigorously agitated by bubbling argon through it. The activity of the decanted surface was measured through an aperture 1.5 cm by 0.5 cm in a lead shield with an Anton tube geiger counter. Assuming that the active layer on the surface had the same concentration of Tl204 as the decanted liquid, the thickness of the layer could be determined from the measured activity of the decanted material, and the relationship between activity and material thickness. The latter was determined by rolling some of the decanted material into foil and measuring the activity of multiple layers of the foil. The activity At of material of thickness t (in mm) was determined to be A, = Ao(1 - e-22.5t) where Ao is the activity of the bulk material. The results of the measurements of the thickness of the residual liquid layer for six decants are given in Table I. The variation in t is attributed to variations in the decanting procedure and the rate of melting, the latter being difficult to control because of the vigorous agitation of the liquid. The rate of melting was in the order of 2 cm per hr, estimated from the position of the solid-liquid interface during melting. The results indicate that a residual liquid layer of the order of 10 µ in thickness is left on the decanted interface in agreement with the observation on eutectic alloys referred to above. If the mixing of the liquid during melting is not complete, as was

Jan 1, 1962

By A. J. Sedriks

ALTHOUGH the occurrence of a readily visible tarnish on the stress-corrosion fracture surfaces of titanium alloys tested in oxygenated nitrogen tetrox-ide solutions has been reported,' the possibility that the formation of this tarnish is a requirement for cracking to proceed does not appear to have been considered. It has been proposed that failure occurs in this system as a result of some electrochemical-mechanical process.2 However, recent studies3-6 of the stress-corrosion cracking of a brass in certain ammoniacal solutions, which also cause visible tarnishing, have led to the view that failure occurs by the repeated formation and fracture of a brittle surface film of cuprous oxide. The purpose of this note is to point out the similarities which exist between the tarnish which forms on a brass and that found on titanium alloys failed in nitrogen tetroxide, and to suggest, by analogy, that a similar tarnish-rupture mechanism may be operative in the latter case. The titanium alloy selected for the present study contained 5.2 pct Al, 2.5 pct Sn, 0.025 pct C, 0.16 pct Fe, 0.014 pct N, 0.012 pct H, 0.07 pct 0, and 0.002 pct Mn by weight. Vacuum-annealed alloy strips measuring 4 by 0.25 by 0.04 in. were used to prepare self-stressed test specimens. Each specimen was made from two strips by bending the end portions and spot welding them together to produce curved sections of uniform bending stress. (The exact details of preparing such specimens have been described by Lisagor el al.7) The curvature in the strips determines the ma-magnitude of the outer fiber stress, which in the present specimens was 100,000 psi (yield stress = 120,000 psi). The specimen surface in the spot-welded end regions was shot-peened to induce compressive stresses and thereby eliminate the possibility of stress-corrosion cracking in these regions. The test environment was nitrogen tetroxide, initially containing 99.5 pct N2O4, 0.1 pct H2O, and 0.08 pct C1, through which oxygen had been bubbled for 30 min. During testing the tetroxide was subject to an oxygen pressure of 250 psi. The duration of the test was 96 hr, and during this time stress-corrosion cracks propagated through some 50 pct of the thickness of the specimens. After testing, the tarnish was liberated from the fracture surface by immersion in a methanol-5 pct bromine solution, and then examined by electron dif- fraction and transmission electron microscopy using a JEM-7 electron microscope. The possibility that the bromine solution had affected the structure of the tarnish was investigated by an "in silu" examination of the stress-corrosion fracture surface using a reflection electron diffraction attachment designed for handling bulk specimens. Typical areas of the tarnish liberated by the me-thanol-bromine solution are shown in Fig. 1. Fig. l(a) reveals that the tarnish consists of individual platelets, and from Fig. l(b) it can be seen that the platelets are joined together to form a semicontinuous film, the boundaries of the titanium substrate grains being retained in the tarnish. Electron-diffraction patterns taken from these areas exhibited diffraction spots typical of a monocrystal. The diffraction pattern shown in Fig. 2 was taken from the central area in Fig. l(n). Monocrystal patterns obtained from areas containing numerous individual platelets can only be explained by assuming that their growth is governed by the titanium substrate (i.e., their growth is epitaxial). In other areas, the tarnish had folded over or became mechanically damaged, and these areas gave diffraction patterns consisting of "spotted" rings, enabling interplanar spacings of the tarnish lattice to be determined. These spacings, measured using a

Jan 1, 1968

By E. S. Machlin, C. W. Chen

RECENTLY Chen and Machlin' proposed a mechanism for intercrystalline cracking in metals during high-temperature stressing. According to this mechanism the formation of voids at grain boundaries is primarily responsible for intercrystalline cracking. A model has been provided to demonstrate the initiation of submicroscopic cracks and voids at jogs of grain boundaries where grain boundary sliding is inhibited. Submicroscopic cracks can grow as a result of either further grain boundary sliding or localized tensile stress. In the former case, it is believed that grain boundary sliding produces more voids which link together to produce macroscopic cracks and which may lead to the eventual failure of the metal. Concurrently, Nield and Quarrell2 reported their interesting results obtained in a systematic investigation of intercrystalline cracking in two aluminum alloys under various creep conditions. Their observations are generally in agreement with the above mechanism, especially the conclusion that voids are formed as a direct consequence of grain boundary sliding. On the basis of the volume fraction occupied by voids, they could find no confirmation of vacancy condensation as the mechanism for void growth. Furthermore, an important feature of intercrystalline cracking has been likewise pointed out by them that the majority of cracks are not formed at grain corners. Nield and Quarrel1 meanwhile emphasized the importance of grain boundary migration by designating it as one of two main processes operative in the mechanism of crack formation during creep. The designation seems unnecessary because overemphasis of grain boundary migration only complicates the mechanism of void formation. There are two reasons which militate against the inclusion of grain boundary migration in the mechanism of void formation. In the first place, the formation of intercrystalline voids per se does not require grain boundary migration. Secondly, in addition to grain boundary migration, void formation may be minimized by any other process such as plastic deformation which is capable of relieving localized stresses around jogs. Chang and Grant3 have shown that intercrystalline cracking is prevented in aluminum by lattice bending in high stress regions. The influential role played by grain boundary migration in creep has also been realized in our studies. In several cases, voids did not appear at all in grain boundaries whenever grain boundary migration took place prominently during creep. The purpose of this paper is to discuss the effect of grain boundary migration on the formation of intercrystalline voids and other related rupture properties. Experimental evidence indicates that in an unstable grain structure void formation may be markedly modified by structural changes. The abnormally high ductility and the transcrystalline mode of fracture observed in copper at elevated temperatures reveals that effective grain boundary migration minimizes void formation. Grain boundary migration has long been known as a common high-temperature phenomenon in metals with the grain configuration in a nonequilibrium state. Its effect on ductility and mode of fracture has not been recognized until recently.4 Since the introduction of the term "Equicohesive Temperature," the conventional belief has been that below the equicohesive temperature the ductility of metals increases moderately with decreasing temperature until the ductile-to-brittle transition temperature of fracture is reached. In this temperature range, metals fracture in a ductile mode with a "cup-and-cone" fracture surface. Above the equicohesive temperature, ductility remains invariably low and decreases slightly with increasing temperature. The mode of fracture is strictly brittle and intercrystalline. Typical examples have been shown for a brass and copper in Fig. 1 and 9, respectively, in the paper by Greenwood, Miller, and Suiter.5 The observation in the upper temperature range that ductility of metals is low and insensitive to temperature may be explained in terms of void formation at grain boundaries. It is also in accordance with the findings of McLean6 and Fazen, Sherby, and Dorn7

Jan 1, 1961

By M. R. J. Wyllie, H. W. Patnode

In the quantitative interpretation of electric log data it is essential to know the formation factor, defined as the ratio of the resistivity of the formation 100 per cent saturated with brine to the resistivity of the brine.' This concept implies that the formation factor for any given rock is constant irrespective of the resistivity of the brine or solution with which it is saturated. It is apparent that this can be true only when the rock matrix is wholly non-conductive. As reservoir rocks may contain clay or shale having an appreciable conductance one may expect these constituents to influence the determination of true formation factor. The formation factor may be theoretically derived from log data by dividing the resistivity of the mud filtrate invaded formation by the resistivity of the mud filtrate. Such a method of calculntion has implicit in it the assumption that the fluids in the invaded formation are wholly replaced by mud filtrate. that the solid matrix is non-conducting, and that the formation factor of the invaded zone is identical with the formation factor of the uninvaded zone. Since the validity of the first two basic assumptions regarding the insulating character of porous matrices and the displacement of the interstitial fluids in porous media do not appear to be fully established, the formation factors of a number of cores and clay slurries have been measured under conditions suitable for verifying the assumptions and the extent of any errors inherent in them. CORE STUDIES Apparatus and Procedure Resistivity measurements were made on short cylindrical permeable cores which had been previously mounted in lucite.2 The cores were clamped by means of insulated bolts between brass plates about 5 cm square and 1 cm in thickness. The plates were provided with a ring seal to prevent leakage between them and the core mount, and had a centrally located orifice so that fluids could be flowed through the mounted core. The brass mounting plates were used as electrodes and any current flow between them necessarily passed only through the constituents of the intervening core. Fluid saturation of the core, and fluid flow through the core, were effected by a centrifugal pump connected to the outflow end of the core, thus providing a differential pressure across the core of approximately one atmosphere. The procedure used was first to evacuate each core by means of the pump and then to saturate the core with an aqueous sodium chloride solution of known resistivity. The resistance of the core was measured and flow of the solution through the core continued for sufficient time to establish a constant resistance reading. After equilibrium had been reached with one solution, another sodium chloride solution of a different resistivity was flowed through the core and the flow continued until a constant resistance reading was again obtained. This procedure was continued until resistance measurements of the core had been made with a series of solutions within a salinity range from 1.0N NaCl to distilled water. The data obtained enabled the apparent formation factor of given porous rocks when saturated with fluids of different resistivity to be computed and also provided information regarding the ability of an invading fluid to displace interstitial water from a core. Results Berea Sandstone — The first core examined was a specimen of Berea sandstone." This core had been cut essentially parallel to the bedding for permeability studies. The core was clamped in the core holder and saturated with 1.0N NaCl solution and the resistance determined. It was subsequently flushed and the resistance measured when saturated in turn with 0.1N, 0.025N, 0.01N, .005N sodium chloride solutions and finally with distilled water. In flushing the core with each

Jan 1, 1950

Said Plutarch a long time ago, ?To appreciate a man's work at the full, it is well to know the man himself, his circumstances and the incidents of his career." He might as truly have said "gift" instead of "work." Ambrose Swasey, engineer, collaborater with scientists, promoter of engineering research, patron of Engineering Foundation, advancer of the good of mankind, modest gentleman and generous giver, is, happily, well known to a great many engineers, who will therefore more fully appreciate his recent additional gift, for the use of the Engineering Foundation, which; purpose is "the furtherance of research in science and engineering, and the advancement of the profession of engineering and the good of mankind." But full appreciation of a gift of money necessitates more than acquaintance with -the giver and knowledge of the amount. Its timeliness; its inspiration; the character and continuity of its benefits, all must be comprehended. But whose imagination, though far-visioned as the great telescopes Mr. Swasey has built, can see the limits of benefit of such gifts as he has made to the Engineering Foundation, attracting-as they will-other gifts and evidences of, devotion to a great cause-? Every such gift lays responsibilities upon the recipients. Will American engineers grasp not merely, their pecuniary value but also emulate the spirit of fraternity and desire for harmony which have accompanied them? Shall we not work together and with Ambrose Swasey to advance still further the good of mankind, thus to demonstrate an acceptance of our obligations to humanity which is a counterpart in a democracy of the noblesse oblige of aristocratic tradition?

Jan 12, 1918

By J. W. Ristori

During the year 1940, production of crude oil in RiIexico totaled 43,914,000 bbl., or 2,776,000 less than in 1937, the year before expropriation. The 1940 output was I,2000,000 higher than in the previous year. In 1937, Poza Rica production accounted Declines in exports of Panuco crude, fuel oil and gasoline were recorded but these were more than offset by increased exports of 4,000,000 bbl. of Poza Rica crude, which was the approximate amount shipped to Sinclair during 1940 under the terms of the settlement. Over-all exports increased by 1,500,000 bbl. over the preceding year. The outstanding development regarding the destination of Mexican exports in 1940 was the increase of I0,000,000 bbl. in the exports to the United States. Exports to Germany ceased toward the end of '939 and to Italy in the second half of 1940. During the year 1940 the Sinclair interests and the Mexican Government settled their expropriation question. By the terms of the settlement Sinclair is to be compensated by cash payments and oil-purchase contracts. On Dec. I, 1940, Ada Camacho was inaugurated President of Mexico for a term of six years. Among his first acts following his election were: I. A proposal to change the Constitution to restore Supreme Court Judges' terms to life tenure. This has been ratified by both chambers of the Mexican congress and is now before the legislatures of the States of Mexico for ratification. The, taking away of the administration of the railroads from labor and restoration to the State.

Jan 1, 1941

By J. W. Ristori

During the year 1940, production of crude oil in RiIexico totaled 43,914,000 bbl., or 2,776,000 less than in 1937, the year before expropriation. The 1940 output was I,2000,000 higher than in the previous year. In 1937, Poza Rica production accounted Declines in exports of Panuco crude, fuel oil and gasoline were recorded but these were more than offset by increased exports of 4,000,000 bbl. of Poza Rica crude, which was the approximate amount shipped to Sinclair during 1940 under the terms of the settlement. Over-all exports increased by 1,500,000 bbl. over the preceding year. The outstanding development regarding the destination of Mexican exports in 1940 was the increase of I0,000,000 bbl. in the exports to the United States. Exports to Germany ceased toward the end of '939 and to Italy in the second half of 1940. During the year 1940 the Sinclair interests and the Mexican Government settled their expropriation question. By the terms of the settlement Sinclair is to be compensated by cash payments and oil-purchase contracts. On Dec. I, 1940, Ada Camacho was inaugurated President of Mexico for a term of six years. Among his first acts following his election were: I. A proposal to change the Constitution to restore Supreme Court Judges' terms to life tenure. This has been ratified by both chambers of the Mexican congress and is now before the legislatures of the States of Mexico for ratification. The, taking away of the administration of the railroads from labor and restoration to the State.

Jan 1, 1941

By Stanley W. Ivosevic

The commercial success of this low-grade property by Houston Oil and Minerals Corp. (succeeded in interest by Houston International Minerals, Inc.) resulted from credibility of analytical data furnished by the property vendor upon initial examination and from other favorable geologic criteria in evidence; from negotiation of lease terms not detrimental to project economics; from entrepreneurial exploration management; from an encouraging attitude by the US Forest Service; and from the favorable mining and metallurgical characteristics of the ore body. The potential of the property, but not its location, was brought to the attention of the project manager (the author) by the vendor some time before accepting employment with HO&M. In December, 1977, the vendor granted an examination to the project manager, by then an employee; and a lease to the 15 mining claims embracing the property was executed in April, 1978. (See Fig. 1.) Field work and extensive claim staking in this virgin district commenced in May, with drilling beginning in August. At the point that an apparent discovery was recognized in October, only $98,000-including property payments-had been expended on the project. By April, 1979, the deposit was drilled out on 60-m (200-ft) centers and a preliminary re- serve estimate, discounted cash-flow analysis, and recommendations for mine development and additional exploration submitted to management-all at a cost well below budget. The property was recommended for acquisition after matching favorable geologic criteria developed by the project manager. Favorable lithology, structure, and geochemical zonation converged on a subdued low-temperature hydrothermal alteration zone subtly expressed on a pediment surrounding the heart of the property, from which approx [ ]

Jan 1, 1985

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so, that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining, reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will, use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 6, 1916

By G. Austin Schroter, Ian Campbell

ALTHOUGH there is now an extensive literature on the bleaching clays, not a great deal of material is to be found concerning the geological features of these deposits and their bearing on problems of exploration and development. At the same time, chemical and crystallographic research on the clay minerals during the past few years has laid a suitable foundation upon which to base conclusions of economic value drawn from field observations. All of the criteria and deductions herein presented are based upon extensive field work by the senior author, both in the United States and Canada, and when subjected to the ultimate tests of development and exploitation they have held up remarkably well, despite the fact that many of these conclusions apparently have not been reviewed in the literature heretofore. The nomenclature of the bleaching clays is rather confusing in the light of present-day commercial standards and has even led to litigation." The old term "fuller's earth" is largely based upon trade usage and the definition of the term therefore is dependent upon the changing standards of commerce. For statistical purposes the Bureau of Mines81 classes as "fuller's earth" all natural bleaching or filtering claylike materials that possess high adsorptive capacity without previous chemical treatmerit or activation. Conversely, the so-called activated or acid activated clays are now generally recognized as any clay mineral or mixture of the clay minerals whose adsorptive capacity has been developed to commercial standards by chemical or physical treatment. Therefore, without attempting to propose any additions to the nomenclature of bleaching clays, this paper will refer to naturally adsorptive clays and activable clays, respectively, for the two types indicated.

Jan 1, 1940

By Ralph Arnold

SOUTH of Havana, there is a geanticline that extends from Madruga to Bejucal. The older formations outcrop in the. east and gradually go under until in the Bejucal region the entire geological column lies below the surface, with the Nazareno formation at the top. The well we are now drilling is located at the deepest part of the section. I think there is a good chance to obtain oil, for the conditions are like those in the Santa Maria field in California. In both places asphalt occurs in the upper shales in the form of dikes that break through the older formations. The drilling in the Santa Maria field was brought about by the evidence offered by the asphalt deposit, which overlaid the oilfields. Detailed geologic work in both fields discloses pretty well defined domes with minor faults. Between Madruga and Bejucal, the San Francisco formation has come, to the surface in a dome and still farther east there are other domes near the base of the formation in which the Madruga chalk is the surface rock. The Bejucal dome was selected for drilling because, it gave the greatest evidence of petroleum in the form of asphalt and because it offered three chances of striking oil in the three possible oil horizons below the top of the Nazareno formation. The hole is now 2600 ft. deep and has shown considerable gas and some oil. The lowest gas sand will probably yield from 2,000,000 to 3,000,000 cu. ft. per day. Very heavy mud has been used in drilling this hole and this has held back gas and oil indications.

Jan 3, 1925

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and. from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information willreceive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them. .

Jan 1, 1916

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all. week-days, except holidays, from Sept. 1 to June 30; and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 9, 1916

By Carle Hayward

AT THE February, 1916, meeting of the Institute, a paper presented by Hayward and Raymond gave the results of a study on the effect of time in tempering medium-carbon steel, when the following conclusions were reached: It is not fair to consider the question settled when only three specimens were used for each treatment, but the results obtained indicate that for reheating quenched medium-carbon steel to temperatures below 500° it is only necessary to heat it through. Longer heating has little or no effect on the tensile strength, ductility, or hardness. At temperatures above 500°, increasing the time of treatment causes a slight falling off in hardness and tensile strength with a corresponding increase in ductility. In the discussion of the paper these conclusions were attacked and evidence presented that seemed to throw doubt on their accuracy. The authors, however, showed that this evidence was based on high-carbon or alloy steels and no facts regarding medium-carbon steel were presented. During this study the heat treatment was carried out in a small electric resistance furnace. It held nine specimens, but when these were placed in the furnace the temperature was lowered to such an extent that 30 to 40 min. were required to reach the desired heat. The authors pointed to this as a weak point in the investigation and it seemed wise to supplement the research by work on similar steel but using a different method of heating. This has been done and the results are given in the present paper. The Rhode Island Tool Co. cooperated by furnishing the steel and turning the tensile specimens.

Jan 1, 1922

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 2, 1915

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 1, 1915

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all weep-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining-maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining-reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 3, 1914

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and from 9.A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library by forwarding copies of mining reports, maps privately issued, and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 4, 1916