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By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318' C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430' F. (778" C.)

Jan 1, 1923

By John P. Goheen

Considerable work has been done in developing a pyrometer to measure the temperature of molten brasses, bronzes, and aluminum in the crucible. On account of the high melting points and the amount of zinc and sulfurous fumes given off from molten brasses, the conditions are somewhat severe for a thermocouple of standard design; but satisfactory results are obtained with a portable pyrometer, 3 ft. (0.9 m.) of connecting lead wire, and a special 5-ft. nickel-nickel chromium thermocouple, composed of rods 1/4in. (6.35 mm.) in diameter. The lower 12 or 24 in., as desired, may be made detachable so that new tips may be connected at little trouble or expense. The portable instrument need not be of the extreme high-resistance type, as the movable parts of the galvanometer of a lower resistance instrument may be better constxucted to withstand the continuous handling such an instrument receives. Platinum-platinum rhodium thermocouples, protected with porcelain and graphite tubes, have been used, but the lag in registering the temperature is too great. It has been found that the range of temperature for various brasses is as follows: Red brasses...............2200-2250" F. (1205-1234" C.) Yellow brasses............2250-2400" F. (1234-1318' C.) Bronzes..................2300-2550" F. (1260-1400" C.) A recent test with a portable pyrometer having a range of 2600" F. with a bare 1/4 in. heavy exposed couple 5 it. long and a handle attached at the upper end showed that the temperatures of molten aluminum under varying conditions in an oil-fired crucible furnace and one of the Simplex type were as follows: CRUCIBLE, OIL-FIRED FURNACE SIMPLEX FURNACE Temperature of metal in furnace....... 1540" F. (837" C.) 1530" F. (834" C.) Temperature in ladle after skimming at furnace......................... 1480" F. (805" C.) 1440" F. (784" C.) Temperature in ladle after skimming at floor near mold................... 1440" F. (784" C.) 1430' F. (778" C.)

Jan 1, 1923

By E. H. Roberts, L. G. Swenson, F. C. Nix, R. A. Morgen

The binary system lead-antimony has been the subject of comprehensive investigations in these laboratories by Dean1 and his associates. The effect of a third constituent on this system, particularly on the lead-rich alloys in which dispersion hardening was found, has a commercial value as well as an academic interest. This paper covers the effect of the addition of copper, bismuth and tin, all of which are likely to be found in commercial lead-antimony alloys, and is divided into three parts, as follows: I. The System Lead-A~ili~r~ony-Copper II. The System Lead-Antimony-Bismuth III. The Lead Corner of the System Lead-Antimony-Ti11 These three systerrls are of three different types, and hence may be considered as covering three general kinds of additions. Bismuth forms no compounds with either lead or antimony and forms solid solutions with both. Copper forms several compounds with antimony as well as solid solutions but with lead it forms a two liquid layer system and no appreciable solid solution. Tin is soluble in both lead and antimony in the solid state and also forms a compound with antimony. The effect of small amounts of bismuth on the lead-antimony alloys is small, having no appreciable effect on the solubility of antimony. The temperature of the solidus floor is lowered appreciably by the presence of bismuth, cutting down the range of heat treatment. Copper, on the other hand, due to compound formation, increases the apparent solubility of antimony. The excess antimony is tied up with the copper finally and so is not available for dispersion hardening. The net result of addition of small amounts of copper is to shift the dispersion hardening peak of the

By J. A. Capp

For certain classes of electric railways a steel conductor is preferable to the oldcr atld more commonly used overhead trolley-wire. The third-rail presents a rather better appearance, because of the absence of an overhead structure; it is easily installed, cheaply maintai~ied, presents s large area for conducting and collecting the current, and is therefore particularly suitable for high speed and heavy service. With costs calculated on the basis of equal coilductirity in rail aud trollej-wire, the third-rail constrrictiol~ is cl~caper than thc overhead trolley. But the average interurban road will lise a trolley-wire of considerably less conductivity than would be obtained with the smallest size steel rail (about 60 lb. per pard) that mould ordinarily be used, and here the first clost of trolley construction would generally be less thau that of the third-rail. While no third-rail installation has jet bee11 in operation long enough to give figurcs of value, it ~vould appear that the cost of maintenance of the thirdrail construction should be less than that of the overhead trolley. This consideration, together with that of sightliness and adaptability (particularly in the case of terminals, yards and very heavy or high-speed service), will frequently off'set the higher cost of the third-rail construction and make it the preferable means of' conducting the current from thc generator to the car-motor. For the first third-rail installations, old track rails were used when obtainable, and these old rails were supple~rlented with new rails of standard T-section and composition. With the coming of the very heavy, high-speed service during the past few years, the resistance of these old and new standard T-rails was found to be so high that they mould not carry the high currents necessary without too great a drop in the line-potential. The rails would, therefore, have to be suppleme~~ted with addi-

Jan 1, 1904

By Richard W. Lodge

Several methods, both wet and dry, for the assay of zinc-box residues from the cyanide process, have been described in recent years, and each of them has been claimed to be superior to all others. In the year 1901, a paper, entitled "Assay of Zincy Precipitates," was published ill the School of Mines Quarterly to the purport that the scorification method for the assay of zinc-box residues was absolutely unreliable. In order to shed light on this matter, the following experiments were undertaken by Messrs. C.B. Hollis and F. D. Kehew, undergraduate students at the Massachusetts Institute of Technology. The zine-box residues used were obtained through the courtesy of Mr. H. R. Batcheller. The samples were very rich and varied greatly in the fineness of their condition. SCORIFICATION-ASSAYS. In the preliminary tests, the charge, which was weighed on a chemical balance, consisted of 0.1 Assay Ton of residues mixed with from 30 to 35 grammes of test-lead and placed in a 3-in. scorifier, over this an additional quantity of test-lead (from 30 to. 35 grammes) was placed for a cover, and borax-glass, varying in quantity from 3 to 15 grammes, was sprinkled over the top of each charge of the various assays for a cover. The charges were scarified in a muffle-furnace heated to the ordinary temperature which is used in scorification; in some cases the door of the muffle was left open, while in others it remained closed. Generally, the charges spit badly, especially in the assays that were made with door of the muffle left open, or in those in which the door was opened too quickly. The results of the preliminary assays showed: 1. That in order to obtain approxi-

Jan 1, 1904

By John Blatchford, H. O. Hofman

The leading antimony mineral is stibnite. In smelting stibnite ore two processes are available, precipitation and roasting-reduction. The former is suited only for high-grade ores. As low-grade ores are more common than high-grade, roasting-reduction is of greater importance than precipitation. In the roasting process the aim may be to leave the oxidized antimony in the ore, or it may be to volatilize as much of the antimony as possible, collect the volatilized oxide as a rich intermediary product and smelt it for antimony, leaving the gangue poor enough to be considered a waste product. Whichever way the roast is conducted certain difficulties inherent in stibnite are encountered. These are: 1. The low melting point of stibnite which, according to Pélabon,' is 550°C., according to Wagemann2 540°C., and according to Borgstroma 546°C. 2. The ignition temperature: According to Friedrich,4 stibnite, if heated in air, begins to oxidize at 290°C. if the size of a grain is 0.1 mm. in diameter; at 343", if 0.1 to 0.2 mm.; and 430" if 0.2 mm. 3. The fusibility of a mixture of Sb2S33 and Sb203 which in the form of kermesite (Sb2S3)z.Sbz03 melts at 517°C.6 4. The volatility of Sb2Ss and SbzOs, for which no numerical data appear to exist, although practical experience has shown that they are volatile at low temperatures. As regards the oxidation of metallic antimony, we have the experimental evidence of C. F. Plattner6 that when fused and brought to a red heat, it burns with a bluish-white flame to Sb2Oa which passes off as a

Jan 1, 1916

By Edward W. Parker

This plant was built in 1907 at the Bankhead mines to manufacture briquettes by the Zwoyer process under license from the Zwoyer Fuel Go., of New York, N. Y. The building was constructed to contain two units, each of a capacity of 10 tons per hr.; one unit was installed at the time the building was constructed, and the second unit is now being built. The coal used is an anthracite, which is more friable than that of Pennsylvania, and, as a consequepce, a larger percentage of dust or waste is produced, which was formerly thrown upon the slack-pile as waste, but is now passed to the " dust-bin " in the breaker, from which it is conveyed to the briquette-plant. An average analysis of the coal, published by Lewis Stockett and 13. R. Warden,' is as follows: Per Cent. Moisture,.........0.50 Volatile,..8.00 Fixed carbon,... 83..50 Ash,.......8.00 Total,.100.00 Sulphur,.........0.40 per cent. Specific gravity,...... 1.40 Color of ash,.white Heat value,.......14,000 B.t.u. The plant is run under two 12-hr. shifts, the force consisting of 1 superintendent for both shifts, 1 engineer for each shift, 1 briquetter for each shift, 1 helper for each shift, 1 laborer cleaning up for each shift. In the pitch-melting house, 2 men are on duty for one shift. The steam for the engine is furnished from a central boiler-plant, which also supplies steam for the breaker, the electric light and power-plant, machinery-shop, and boiler-shop. During March, April, May, and half of June, in 1907, the

Jan 1, 1909

By T. Egleston

The importance of making analyses of gases in furnaces which are used for metallurgical purposes is every day growing more and more evident. It is the only method of understanding the reactions that take place in the furnace, and of economically conducting the operations both with regard to the fuel used and the reactions which take place on the bodies to be subjected to the influence of the heat and gases. As a knowledge of the composition of gases is becoming every day more necessary to the proper conduct of furnace operations, it seems desirable that furnace managers should generally know that the analysis of gas for commercial purposes is neither difficult, tedious, or expensive, and that it does not necessarily imply the use of corrections requiring difficult instrumental observations and long and tedious mathematical calculations. Any method, therefore, which will tend to render these analyses simple will also tend to having them made and repeated as frequently as the analyses of the ores and other materials charged in the furnace. They should be made even more frequently, as their composition is affected by any change in the condition of the furnace, and a knowledge of their composition will give a ready clue to the unseen and otherwise not easily detected changes which are taking place. The only practicable method of making industrial analyses of gas is that of measuring volumes in graduated tubes. The methods by

By Grafton M. Thrasher

For the proper discussion of this subject it is necessary to incorporate in this paper the substance of part of an article published by me in Metallurgical and Chemical Engineering for January, 1915. Several years ago, while I was chief chemist for a malleable-iron company, it occurred to me that the mere regulation of silicon was not sufficient to produce the desired degree of chill. But only after repeatedly encountering this fact in both open-hearth and air-furnace, as well as cupola metal, was I led to regard variation in the total carbon as the principal cause of disturbance; and I resolved to determine the total carbon as well as the silicon in every heat, and by a carefully prepared test piece to gauge the approximate degree of chill. The test piece selected was a round plug, 2 in. in diameter and 12 in. long, cast on end

Jan 1, 1916

By J. J. Crowe, G. K. Burgess

PAGE, Theories of Allotropy of Iron........... 667 Previous Determinations of A2 and A3 in Iron........ 668 Critical Ranges as Determined by Expansion........ 669 Critical Ranges by Thermoelectric Observations........ Critical Ranges in Terms of Crystalline Structure....... 670 Critical Ranges as Detected by Mechanical Methods...... 670 Critical Ranges as Given by Electrical Resistance....... 670 Critical Ranges as Determined Magnetically........ 671 Critical Ranges as Determined Calorimetrically....... 673 Critical Ranges from Heating and Cooling Curves....... 673 Summary of Previous Determinations of A3 and A2 in Pure Iron.... 675 The Present Investigation............ 678 The Experimental Method........... 678 Arrangement of the Apparatus.......... 679 The Measurements of Temperaturc.......... 679 The Measurement of Time........... 679 The Thermocouples............ 681 Temperature Scale and Calibration of Thermocouples...... 681 Mounting of Thermocouples........... 682 The Differential Measurements.......... 682 The Furnace and Accessories........... 682 The Vacuum Pump............ 683 The Energy Supply............683 The Rheostat.............. 683 The Materials Investigated............ 685 Sources of Iron............. 685 Preparation and Description of Samples......... 685 Chemical Analyses............. 687 The Experimental Data............. 688 The Preliminary Observations.......... 688 The Definite Series............691 Description of the Plotted Curves........... 694 The Effect of Plotting at Different Intervals........ 694 The Curves of the Definite Series.......... 695 . The Curves of the Preliminary Series......... The Existence of Other Critical Ranges......... 696 The Microscopical Examination........... 697 Summary and Conclusions............ 698 Bibliography............... 701 Plates................ 704

Jan 1, 1914

By Edwin C. Holden

In making the original estimates for a report recommending the cyanidation of Ymir stamp-mill tailings, the writer was unable to find in any of the standard works on cyanide-practice certain data applicable to the local conditions; nor has he as yet seen quite the same practice recorded in the rapidly growing literature of cyanidation. To present these figures, together with a few novel features of local practice, the present paper is offered. The ore treated is obtained from a fissure-vein of steep dip, occurring in a slate country. The ore-body is lenticular in plan, swelling from 4 ft. in width at one end to a maximum of 42 ft., and tapering irregularly to less than 18 in., where payvalues cease. In the wider portions of the fissure the ore is mixed with more or less horse-matter from the walls. The clean ore is white, massive quartz, with from 8 to 12 per cent of sulphurets; the latter being pyrite, sphalerite and galena, the predominance being in the order given. The precious metal tenor is variable, the gold more closely following the pyrite, the silver the galena. The present mill-supply is practically all from below the oxidized zone. The unavoidable admixture of horse-matter and stope-filling with the ore as mined, affects more or less the character of the mill-feed, which sometimes contains from 10 to 25 per cent of slate. During the last three months of 1902, the mill-feed carried 0.3977 oz. gold and 1.903 oz. silver per ton of 2,000 lb., 2.65 per cent lead and 2.92 per cent zinc. The iron, unfortunately, was not determined. The Ymir mill and mine have been fully described elsewhere;* suffice it to say of the milling that the crushed ore,

Jan 1, 1904

By W. Wanjokow, H. O. Hofman

In the metallurgical treatment of most metallic sulphides it is usually necessary to carry on a roasting-operation. In some cases the raw ore will have to be roasted; in others the intermediary product, matte, produced in smelting the ore; again, both ore and matte may have to be subjected to oxidation at elevated temperatures. Most metallic sulphides, when given an oxidizing-roast, pass through the state of sulphate before they are converted into oxides. All metallic sulphates are completely decomposed by heat, with the exception of those of lead and bismuth, but the temperatures at which decompositions take place vary with the metals. Some metallic sulphates are converted directly into oxides, others first form basic salts. Alkali-earth sulphates show a behavior similar to that of metallic sulphates, while alkali sulphates do not part with their sulphur trioxide even at elevated roasting-temperatures. The older data on the decomposition of metallic sulphates by heat are only approximations. Thus Kerl' gives the order in which metallic sulphates are decomposed with increasing temperatures as (Ag2, Fe, Cu, Zn, Ni, Co, Mn, Pb) SO,. More recent statenlents give definite temperatures and modify the formerly accepted order of decomposition. But the temperatures given by various observers do not agree. The reasons for this are to be found mainly in the method and manner of carrying out experiments. Four methods have been used: 1. Heating in an evacuated tube; 2, heating in a tube closed at one end, without air-cur-

Jan 1, 1913

By J. S. Hardison

In the fall of 1912, the appearance of water in the oil of the Nevada Petroleum Co., Coalinga, Cal., made necessary the installation of a dehydrating plant to reduce the water below the 3 per cent. limit prescribed by the agency. Unlike the mining industry, technical literature of the oil industry is limited and extremely unsatisfactory. Until the recent efforts of the Petroleum and Gas Committee of the American Institute of Mining Engineers, no concerted movement has been instituted to secure publication of papers dealing with the problems of the oil business, and because of the additional fact that dehydrating of oil has not been practiced in California to any extent up to comparatively recent time, it was found necessary to experiment in order to determine the most satisfactory plan for this purpose. It is easy to write regarding successful enterprises, but, while not SO pleasant, it is equally desirable to write of failures so that others may be saved the loss incident to such investments. The water in this oil occurs both free and as an emulsion. Free water easily settles out, but the emulsion requires treatment. So far as can be determined, the emulsion consists of globules of water surrounded and enveloped by a film of oil. Starting with this hypothesis the theory has been evolved that in order to break up this emulsion the water must be heated at least to boiling point, when an explosion takes place destroying the globule. Unfortunately, this condition was not recognized in the installation of the first plant, which was planned on the following lines: A heater was arranged so that all the oil from the wells could be heated before reaching the shipping tanks, these being already fitted with coils for steam heating. Tanks were filled with about 4 ft. of water, live steam was turned into the coils and the water brought nearly to the boiling point, when the heated oil was run in. This for a time was partly successful, but the length of time necessary to apply this heat was too great for practical operating.

Jan 1, 1915

By John Blatchford, William T. Hall

The product obtained by roasting stibnite is likely to contain some unoxidized antimony trisulphide and a mixture of antimony trioxide and antimony tetroxide. It was desired to determine, as accurately as possible, the condition of the antimony as well as the total quantity present. Attempts were made to separate the trisulphide and the two oxides by methods based upon their varying solubilities in different solvents, but no satisfactory results were obtained in this way. It was found, however, that by determining the total antimony content, the antimony present as trioxide, and the antimony present as trisulphide, a good idea of the chemical composition of the roasted product could be obtained. The total antimony was determined by dissolving the sample in concentrated hydrochloric acid, reducing the antimony entirely to the trivalent condition by means of hydriodic acid and eventually titrating the antimony back to the pentavalent condition by means of iodine in the presence of sodium bicarbonate1* The details of the procedure are as follows: Weigh out 0.25 gram of the roasted product into a trapped flask (Fig. I), add 4 grams of powdered tartaric acid, 2 grams of potassium iodide and 40 c.c. of concentrated hydrochloric acid. Boil the solution gently f;r 5 min. and then cool to room temperature by shaking the flask while holding it under running water. Then, very carefully discharge the iodine color by the cautious addition of 0.05-normal sodium thiosulphate solution, adding a little starch toward the last. Nearly neutralize the acid with ammonia solution, but leave the solution distinctly acid. Pour the slightly acid solution into 200 c. c. of water containing an excess of sodium bicarbonate and titrate to a permanent blue color with standard 0.1-normal iodine solution.

Jan 1, 1916

By J. Blodget Britton

IN the Journal of the Franklin Institute for May, 1870, there is published a description of a Colorimeter, together with a modification of the method proposed by Professor Eggertz, for determining combined carbon in iron and steel. An instrument of the kind there described, but of a little higher range, though in other respects not differing materially from the one originally made and used in the Iron-Masters7 Laboratory, I now submit to your inspection ; and I propose, also, to make some determinations minations with it for the purpose of showing how quickly they may be made, and enabling you to form some judgment of what reliance can be placed in the results. Professor Eggertz proposed only a single standard, and the solution to be tested should be diluted to exactly correspond in color with that of the standard, and the per cent. of carbon calculated after carefully noting and making allowance for the measures of water used in diluting. In practice, difficulty was found in bringing the color of the normal solution down to the exact shade of the standard; also other difficulties were met with in conducting the process, causing delay and interfering with the accuracy of the results. To materially overcome these, and after numerous attempts, an instrument such as is now before you suggested itself to me; and also I concluded to use a larger quantity of metal than directed by Eggertz, and, in addition, to filter the solution from its insoluble matter before making the comparison; and, more recently, to use an acid of just such strength as would completely dissolve the metal without the application of heat. Experimenting with these changes from the original method I obtained reasonably good results. The instrument, you will observe, consists of a series of tubes, sixteen in number, two and a half inches long, and about half an inch in diameter, standing upright, and securely fastened in a light, portable, walnut-wood frame, but separated one from the other so as to allow just sufficient space between to place for comparison the . tube containing the solution to be tested. The tubes are filled with

By A. H. Kline, E. B. Zimmer, Zay Jeffries

It is well known that many properties of a given metal vary with the size of grain or cell. For most industrial purposes, where high ultimate strength and high elastic limit are desired, the manufacturer tries to produce a fine-grained structure. For some purposes, for example in transformer iron, a coarse-grained structure is desirable. The terms fine-grained and coarse-grained are used only in a relative sense. For example, a fine-grained cast copper might have grains 100 times larger than coarse-grained high-speed steel. Similarly, a finegrained steel rail might have grains or cells 100 times larger than coarsegrained wire, which was made of steel from the same heat. In some metals, the change in grain size is more appreciable khan the changes in any of the properties determined by the tensile test. Furthermore, in metals which have been annealed or subjected to high temperatures, grain size may prove to be a better indication of the life of the metal in use than the tensile test. One of the authors was able to supplant the tensile test with grain-size determinations in the control of metal for a specific use, the latter determination being more indicative of the life of the metal part than the tensile test. A grain-size determination with a tensile stest is, of course, more valuable than either singly. At present there is a decided dearth of data on actual grain-size determinations in metals, and consequently a corresponding lack of ability to interpret the determinations after they are made. It would be desirable to have correlation made between grain size and properties of metals, comparing thousands of determinations. In this way, grain-size determinations might be interpreted in much the same manner that tensile tests are now. Several Methods of Measuring Grain Size One of the chief reasons why more grain-size measurements have not been made is the excessive work involved in making a determination.

Jan 1, 1916

By Henry J. Williams

The main difficulty in the determination of silicon in pig-irons containing very high percentages of that element, has been due to their almost complete insolubility in acids, or mixtures of acids. The object of the present paper, which presents no new principle, is to suggest a method of determination which has repeatedly given accurate results, and which obviates completely the tediousness and uncertainty of the usual slow solution in acids. This method has been tried with pig-irons containing from 7 to 14 per cent. of combined silicon, and properly called ferro-silicons. When reduced to an impalpable powder in the agate mortar, an 11 per cent. ferro-silicon was found to resist the action of all acids, or mixtures of acids, with the exception of sulphuric acid of about 1.25 specific gravity. But the action of this acid, even during long continued heating, was very slow, 72 hours being necessary to com pletely dissolve half a gramme of the metal. The complete decomposition of 1 gramme of the metal may, on the other hand, readily he effected in a few minutes by fusion with sodium carbonate in a covered platinum crucible over a blast-lamp —the idea being to dissolve the silicon, leaving the iron in condi tion to be readily attacked by acids. The silicon dissolves as soluble sodium silicate, and metallic iron remains in a very spongy and finely divided condition. The addition of a little hot water

Jan 1, 1889

By Thomas M. Drown

The use of bromine as an oxidizing agent, particularly for sul phur, has become very general in analysis, replacing the stronger oxidizing acids. The object of this paper is to describe briefly the experience which we have gained with this reagent in the laboratory of Lafayette College in the oxidation of metallic sulphides. Most of the simple sulphides, as blende, pyrite, etc., when exposed to the combined action of an alkaline hydrate and bromine, and finally to hydrochloric acid, are completely and promptly dissolved. The procedure is as follows: The very finely pulverized mineral is first treated, in a beaker, with a solution of sodium hydrate of a spe cific gravity of 1.25, and heated ; bromine is then cautiously added to supersaturation, and finally hydrochloric acid to acid reaction. If any of the sulphide is not taken up, the same operation may be re peated. It is necessary, however, that the mineral be very finely pulverized. Instead of using the pure bromine, a saturated solu tion of bromine in potassium bromide may be used with equally good effect. The process is advantageously simplified by making a saturated solution of bromine in the concentrated alkali. This is done by pouring bromine into a solution of sodium hydrate, of the above given specific gravity, until no more is taken up, and then adding a little of the sodium hydrate solution until the liquid does not give off free bromine. The procedure with this solution is as follows: The pulverized mineral is moistened with, say, 10 cc. of the solution, and heated, then hydrochloric acid added to just acid reaction. Two more additions of the alkaline solution, in amounts of 20 cc. each, are added at intervals of about ten minutes, each addition being followed by hydrochloric acid. The total amount of the alkaline solution (containing the bromine) used is, therefore, 50 cc., and the amount of hydrochloric acid should not exceed that necessary to make the solu tion acid after each addition of the alkali. The mixture should be kept hot. After the final addition of acid, the contents of the beaker is taken to dryness and heated in an air-bath to 110° to 115°C., to render silica insoluble. The dry mass is then taken up by hydro' chloric acid and water and, after filtration, the sulphuric acid is pre

Jan 1, 1880

By J. H. Nead

The experiments herein described were undertaken with a view to investigating thoroughly the influence of carbon on the tensile and impact physical properties of carbon steel. The original comprehensive plan included investigation of a series of steels with varying carbon contents over a wide range of heat treatments. These were to be studied as to their static tensile qualities, and also their resistance to shock as measured by the Charpy impact bending test. A thorough metallographic examination was likewise included in the schedule. The Charpy tests and the metallographic examination have not been completed to date, and are accordingly withheld for another report. All heat treatments, however, have been made, and the static tensile tests have been completed. A description of the procedure of the experiment and the results thus far obtained are therefore reported herein. Conclusions No attempt is made to draw general conclusions from these experiments, but the curves and the data are submitted as being of general importance and wide applicability. Composition of Materials An attempt was made to secure steels increasing in carbon by increments of 0.1 per cent. from 0.1 per cent. up to 0.8 per cent., and from that composition to 1.6 per cent. by increments of 0.2 per cent. Actually, however, steels of the composition given in Table I were procured, and as the carbon contents were arranged sufficiently well so that satisfactory curves could be drawn showing the relation between carbon content and other properties, these steels were used in the experiments.

Jan 1, 1916

By Richard Moldenke

One of the gravest problems of the iron foundry today is the accumulation of sulfur in commercial scrap and its effect on the castings made therewith. The ordinary jobbing castings today show a sulfur content of 0.18 per cent;, and occasionally as high as 0.22 per cent. The product of the foundry during the war is undoubtedly to blame for this rapid increase and conditions will become worse as the millions of tons of gray-iron castings of the war period return to the foundry in the form of commercial scrap. In the ordinary cupola remelting of pig and scrap, at least 0.02 per cent. sulfur is taken up; often double that amount. The high cost and difficulty of obtaining pig iron during the war period compelled the use of considerable scrap in the mixtures; frequently charges containing 90 per cent. of bought scrap were melted. Naturally the sulfur content of the castings increased. Until the advent of the basic-hearth electric furnace, the only method of holding the sulfur within reasonable limits was to use high percentages of pig in the foundry mixtures. Pig iron seldom contains over 0.05 per cent. sulfur, if well made. With pig iron forming 60 per cent. of the charge and the gates, runners, rejections, and bought scrap the other 40 per cent., the sulfur content of the castings can easily be held down to 0.10 per cent. Pig iron, however, costs more than scrap even when melting loss differences are considered, hence as small a percentage as possible will be used. The recent advance in knowledge of rational melting and the consequent reduction in losses directly due to oxidation of the metal and cold iron, has permitted the acceptance of castings with a much higher sulfur content than formerly. The steel industry also is seeking to determine how high sulfur may go with safety. In the iron foundry, however, there is the danger of a low cupola bed or an unduly retarded air-furnace heat, with the consequent raising of the freezing point of the metal and segregation effects resulting from high sulfur with insufficient manganese. The iron foundryman must, therefore, have a means of correcting his

Jan 1, 1922