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By A. J. Carlson, G. M. Marincel, M. L. Hovland, J. H. Healy

Research personnel of Erie Mining Co., a pioneer taconite mining firm on the Mesabi Range, have invented a new method to make an effective 325 mesh separation at high tonnage rates over stationary screens. The company regards this development as historically significant in that it represents the first successful method to commercially screen large tonnages of ore at fine sizes. Erie, which is now completing an expansion program at its plant site near Hoyt Lakes, Minn., has incorporated this screening method as part of that expansion. When completed, the concentration plant will produce 10.3 million tons of iron concentrate, all of which will have been efficiently screened at 325 mesh.

Jan 4, 1967

By G. S. Morison

I have bad considerable experience with the testing-machine at the Watertown Arsenal, having had broken there sixteen large steel eye-bars, besides quite a number of iron bars and two compression members. So far as accurate mid satisfactory results are concerned, the machine is all we could ask for, and the officers who have it in charge, together with their civil assistants, are thoroughly conversant with it 1 details, and entirely competent to make the tests required. The principal defect is that the force is very inadequate. As the machine is arranged, tile weighing apparatus is at one end and stationary, the measure of strain being carried from this to the scale-beam by the fluid in a tube m small that it looks like a wire. At the other end is placed the hydraulic press by which the power is applied; this press is mounted on a small carriage and held by two eight-inch screws about four feet above the floor, which arc of course strained in compression during tensile tests, and in tension during' compression tests. When the stretch of the material has exhausted the throw of the plunger it is necessary to relieve the strain, draw back the plunger, and move the carriage along, which is done by nuts turned by steam working on the large screws. Every specimen placed in the machine must be lifted above the large screws and lowered into position. To do this, crabs, running on travellers, which span the entire room, are placed over the machine, and by these the specimen can be lifted and put in place. The actual time required to make a test depends largely on the amount which the material stretches, bat it may generally be said, that for specimens which will stretch from two to three feet the

Jan 1, 1882

By C. Willard Hayes

The determination of the question whether the Mayari and Moa mining-claims of the Spanish-American Iron Co. have been rightly denounced under the third section of the law of bases rests on the findings in the following questions of fact: 1. Is the mineral an iron-ore ? 2. Is the iron-ore a bog iron-ore ? 3. Is the iron-ore ocher ? 4. If ocher is present, can it be mined separately and independently of the iron-ore ? 1. Is the Mineral an Iron-Orb? Since the material is shown by a large number of analyses to contain from 41 to 50 per cent. of metallic iron and less than

Jan 1, 1912

By Carl Henrich

In the winter of 1895 to 1896, during the construction of the Jackson and Cincinnati railroad, running from Addison, Lenawee county, Mich., to Jackson, Mich., in a northerly direction, I had occasion to observe some interesting geological features, described below, in a cut of this railroad made through the low ridge of gravel and sand, dividing the valley of Silver Lake and Silver Creek from the Goose Lake and Goose Creek valley, in Lenawee county. The surface-deposits of this part of the county are, as is well known, of glacial origin. Gently rounded, long ridges of sand, gravel and clay intervene between the marshy bottoms and the lakes of the valleys. The nature of the deposits, varying from a sandy clay or clayey sand to fine and coarse gravel and pure siliceous sand on the one hand, and to a very tough, fine, uniform and often indurated clay on the other, as well as the irregular and sudden changes, sharply divided, between these materials composing the ridges, in the cuts made through them by the railroad, would admit of no doubt that this country owes its present surface-configuration primarily to the action of the last glacial period, which covered its surface with an immense ice-sheet. The well-known ice-markings on the huge granite, schist, greenstone and conglomerate boulders found everywhere imbedded and protruding from the surface, add their testimony to the other characteristics mentioned. Most of the cuts made by the railway through the ridges showed in a marked degree the irregular arrangement and the sudden changes of and between the materials mentioned above. One cut, however, known as Kelly's cut, or Kelly's gravelpit, about 4 1/2 miles north of Addison, and about 1 1/2 miles south

Jan 1, 1897

By H. F. Miller

Fox some years the prejudice against basic open-hearth steel for casting has been gradually decreasing. Yet many consumers and engineers still cling to acid steel for castings, because of their alleged greater freedom from blow-holes and sponginess. Acid steel has been used for this purpose much longer than basic steel; and the melters in acid practice had it well in hand when basic steel was first tried. Then the necessity of learning a new set of laws for the production of satisfactory basic open-hearth steel for castings became evident. The first of these laws, in my opinion, has to do with the furnace construction. The heat should be melted down as speedily as possible so as to prevent excessive oxidation. I have described in another article ' some furnaces designed by me, and having as one of their features the promotion of quick melting. Size of the Furnace. The hearth of the furnace, however, is a decisive factor in the production of solid castings. The manufacturer should know the size of the heats he intends to make constantly, and should have his furnace built for that size of heat. The hearth should differ in dimensions from that of a furnace making ingotr steel. That is, the bath should be deeper and should have less surface-area. A shallow bath permits the slag to come out soon after the steel commences to flow, and thus prevents the additions from going into the steel, or from becoming uniformly distributed in case they have been put in hurriedly. Under this head comes the very poor practice of making small heats in hearths of a much larger capacity. If into a 25-or 30-ton furnace only 12 or 15 tons of metal is charged per heat, the proportion of heats that will be wild, or show signs

Jan 1, 1913

The Subcommittee on Manganese, of the A.I.M.E. Committee on Industrial Preparedness, prepared under date of Jan. 24, 1924, for and at the request of the War Department, a confidential report on manganese as an element in the problem of national defense. This report was later released and published, in slightly modified form, as a separate pamphlet. After the lapse of eight years, in view of the vital position of manganese in the problem of industrial preparedness agenist a war emergency, the War Department made a request to have the onclusions of 1924 reviewed and brought up to date. To comply wi' this request the manganese subcommittee was reconvened and ex' tive studies were once more made of the entire subject of mang? . A new report, with specific recommendations, was submitted + War Department in February, 1932. This second report, with 4. L specific conclusions and recomrnendations expressed to the War Department omitted, has now been released and is hereby published. Following a rather brief discussion of uses of manganese and classification of manganese ores, requirements and sources are dealt with at some length. Domestic ferro-grade reserves are estimated on the basis of price and are shown by means of a curve where tons of metallic manganese are plotted cumulatively against prices ranging from 50¢ to $1.00 per unit; thereby indicating at a glance the tonnage which the Committee believes would become commercially available at any particular price per unit. Foreign sources of ore are described and foreign prices which the domestic producer must meet are considered. The question of a war-emergency reserve is then analyzed, requirements are balanced against apparent resources, and the principal conclusion that emerges is that a war reserve or stockpile is still vital to national defense.

Jan 1, 1934

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, Cornell M. E., graduate, aged 31, married. Will soon complete 2 years' engagement in the Russian oil fields. Eight years' practical experience in drilling for and producing oil. Can speak Russian fluently and some French and German. Open for engagement. Interview after August 15, in the United States. No. 299. Member, graduate mining engineer. Married. Aged 38. For past 6 years, general superintendent of large silver mine in. Mexico. Desires connection with responsible mining company, preferably in the United States. Has had 15 years' experience in the United States and Mexico, including mine engineering, sampling, examinations,' milling and mine superintendence. No. 312. Metallurgist, 4 years' experience in electric furnace operation on steel, ferro-alloys and smelting of ores, both practical and research, desires position as metallurgist or superintendent. No. 314. Member, technical mining graduate. 5 years' experience in coal and metal mines and construction work. Married. Aged 27. Employed at present. Interview in Salt Lake City or Denver. No. 316.

Jan 10, 1916

The new, internationally-owned Savage River Mines iron ore mining, concentrating and pelletizing project, built and operated by Pickands Mather & Co. International, was dedicated March 6 at Port Latta, Tasmania, Australia. Construction of the $79 million project began in 1965 and involved an open pit mine and concentrating plant plus a complete town for about 350 employees at Savage River; a 53-mile pipeline to transport the concentrates; a pelletizing plant and shipping facilities at Port Latta, which is on Bass Strait separating Tasmania from the Australian mainland. The project has a rated capacity of 2.25 million Ltpy of high-grade magnetite pellets, which will be sold to five Japanese steel companies under 20-year contracts. The open pit mine is located in the central portion of the Savage River deposits. Mining equipment, capable of moving 10 million tpy of ore and overburden, consists of four 6-cu yd electric shovels and 12 50-ton trucks. The concentrating plant, with a design capacity of 5 million tpy of ore, will use magnetic separators to upgrade the ore, which averages 38% iron, to a concentrate averaging 67% iron.

Jan 4, 1968

By Joseph William Pinder

Every millman engaged in the operations incident to the handling of crushing-rolls knows that in ordinary practice, when fine product is desired, the ore-materials delivered to the machine, divided into four sizes, may be estimated, approximately, as follows : Per cent. Papsing a 4-mesh screen,..40 2- " " ........30 " 3/4-inch-mesh screen,.. 20 Larger,...........10 This estimate refers more particularly to the requirements of medium-sized rolls and fine crushing. But, depending largely on the character of work to be performed, the coarser material is often larger and of a greater percentage, while the bulk is always more or less fine.

Jan 1, 1899

By Benjamin Smith Lyman

There seems to be dire need of repeated preachment against the too-frequent sad neglect of instrumental surveying and mapping in geological surveys. The value of the map as an illustration of the statements and opinions of a report is too apt to be overlooked; and its essential necessity in working out during its construction the proper conclusions from the observed facts is generally altogether misunderstood. Practical geology seeks, of course, to ascertain and indicate the character of workable or unworkable beds or veins, their depth, position, dip, and horizontal course, or strike, even below the surface; also their outcrops, and therefore, if workable, their extent; and so, taking account of their thickness and specific gravity, their weight in tons. It might, therefore, be called quantitative geology. For the study of more abstruse geological questions, too, it is in many cases necessary to gain some knowledge, or reasonable opinion, in regard to such hidden facts. In some cases, careful instrumental surveys are made; in others, from necessity or choice, there are few or no instrumental observations. It was said, 15 or 20 years ago, that there was an engineer in the anthracite-regions who was capable of telling, on first glancing at a new place, exactly what coal-bed was to be found there at a certain depth, and how thick—a splendid second-sight! "' 0, there be,' " you may be tempted to exclaim, " geologists ' that I have seen' geologize ' and heard others praise, and that highly, not to speak it profanely, "'—but let them pass without being fully characterized, lest the temptation towards profanity be altogether too strong. Yet such second-sight does not exceed the expectations of many men of imperfect geological knowledge, men who have heard of marvel-ously successful geological predictions, but are unaware of

Jan 1, 1910

August 10 to 14, 1914, inclusive Headquarters will be at the Hotel Utah. The following program of the meeting has been arranged y the Local Committees: Monday, August 10.-Members and guests will register at the Secretary's desk in Room C-38, Hotel Utah, and receive the official badges, booklets and programs of the meeting. At 2:30 P. M., there will be an organ recital at the Mormon Tabernacle, after which members and guests will be taken for a trip around Salt Lake City in sight-seeing motor cars. At 8:30 P. M., the ladies will assemble in the lobby of the Hotel Utah, where they will be met by the members of the Ladies' Entertainment Committee, and will be taken for an automobile drive about the city. At 8:30 P. M., a technical session will be held in the ballroom of the Hotel Utah. The following papers will be presented: F. W. BACORN: An Amendment to Sales's Theory of Ore Deposition. C. W. GOODALE: Drumlummon Mine, Marysville, Mont. I. B. JORALEMON: The Ajo Copper-Mining District. STUART CROASDALE: Leaching Experiments on the Ajo Ore. FRANK R. VAN HORN: The Occurrence of Bournonite, Jamesonite, and Calamine at Park City. HOWLAND BANCROFT: Dip Chart. M. N. ALLING: Ancient Auriferous Gravel Channels of Sierra County, California. B. S. BUTLER AND H. D. MCCASKEY: Copper Ores of the New London Mine. GEORGE A. PACKARD: Rope Idlers in the Raven Shaft. ARTHUR CROWFOOT: Development of the Round Table at Great Falls. FREDERICK LAIST AND A. E. WIGGIN: The Slime-Concentrating Plant at Anaconda. W, L, AUSTIN: The Treatment of Copper Ore by Leaching Methods. W. L. AUSTIN: Leaching Copper Products at the Steptoe Works.

Jan 8, 1914

By W. F. Carew, F. A. Crossley

IT has been reported that the Ti-8 pct A1 alloy is ductile as water quenched from 800°C but brittle as annealed at 650 °C." The present, somewhat limited, investigation was undertaken to discover the cause of the embrittlement. In order to evaluate to some extent the continuity of the embrittling phenomenon, alloys of 6, 8, and 10 pct A1 were studied. Subsequent to the completion of most of this work, Ence and Margolin reported that a Ti,A1 phase exists and that two or more unidentified compounds may exist in the Ti-A1 system.' Materials, Equipment, and Techniques The alloys were prepared using Kroll process sponge of 124 Bhn hardness. In addition, some 8 pct A1 material was made with iodide titanium. The sponge-base alloys were prepared as melts of 4 lb or more by double arc melting. The iodide Ti-8 pct A1 alloy was prepared as 200-g buttons. The alloys were forged at temperatures of 980" to 1150°C. Results of chemical analyses are given in Table I. A Baldwin-Southwark 60,000-lb capacity tensile machine, equipped with an autographic stress-strain recorder, was used for the tensile tests. Standard tensile test specimens, 0.252 in. diam, were used. Standard Charwy V-notch impact specimens were tested using a -kiehle machine. specimens were sealed in evacuated Vycor bulbs for heat treatment. Powder samples for Debye-Sherrer anal- ysis were prepared by filing and screening through 325 mesh. The —325 mesh fraction was taken in an effort to concentrate a microstructural constituent assumed to be less ductile than the a phase. The powder samples were stress relieve2 by annealing

Jan 1, 1958

R. W. NEWCOMB,* New York, N. Y. (written discussiont).-On page 1638 mention is made of a new -instrument with an exceptionally high resistance that has been developed by Charles Engelhard. All friction and wear of moving parts of the moving system has been elimi-nated by replacing the hardened steel pivots and jeweled bearings, commonly used on other instruments, by a double metallic filament, one at the top and One at the bottom, under slight tension. Any pos-sible distortion of the moving coil, because of tension, has been eliminated by introducing a solid spindle as the axis of the coil between the points on the coil where the metallic filament is attached. The filaments serve not only as a support for the moving coil; but also to lead in the current from the binding posts to the moving coil, and as a source of counter-torque; instruments so constructed, do not require leveling, and are mechanically very robust. The clock of the recorder serves only to drive the chart at its specified rate and -to operate a small contact-making device; i.e., there is no other mechanical load on the clockworks. The contact-making de-vice is so constructed that there is a quick-make, a quick-break, and a wiping effect while the contact is being made. Contact surfaces on this switch are of platinum platinum-iridium. The operation of this contact, which occurs once each minute, sends a current, from a 6-volt supply; through a solenoid magnet, which operates the depressor bar mechanism in the case of the single-record instrument; in the case of the multiple-record instrument, it operates the automatic switch and color-changing features, as well as the depressor bar.

Jan 12, 1919

By H. D. Pearsall

It is well that the usual system for supplying water at high pressure purposes of hydraulic mining possesses serious disadvantageense, delay and large annual repairs. Where plough work possible, the first expense of the ditch is moderate; but it is verynree years before the work is solid and the ditch water-tight, lxPenditure for repairs being needed during this time and greaf water occurring. Moreover, in the course of a long ditch, it happens that part of it has to traverse a diffi cult country fluming, masonry, or other expensive construc tion is necessich makes even the first cost high. The life of flumes is also) The ad visa if pumping water instead of supplying by gravity has therefore been suggested, when sufficient water-power for the purpose oping happens to be available. But the expense of the requiuchinery and its complication, which involves skilled attend expensive wear and tear, has hitherto pre vented. The author ever, having been called upon to make plans and estimates for Lulic works for an extensive placer-mine in Colo rado, has such in devising pumping arrangements which are free from these sections, and are in fact estimated to cost less than half what a din the usual plan would cost. Several incidental advantages in plan also accrue, which will be referred to more particularly be The works placer-mine have not yet been carried out, on account of final arrangements, but in the meanwhile an hy draulic 'engineilar to that designed for the mine, has been con structed and so work for other purposes in England; and in order to explane plan which I have recommended for working the placer-mine will' describe this, which is actually at work, in preference to cibing the one which is not yet constructed. The engine machine acts on the principle of the hydraulic ram

Jan 1, 1888

By H. W. Turner

Lying to the east of the Rio Grande, in central New Mexico, is a long N. and S. mountain range, broken into separate ridges at several points. These have received separate names; the mountains at the south end, near El Paso, being known as the Franklin mountains, and then, following successively, to the north, the San Andreas range, Sierra Oscura, Manzano and Sandia mountains. At the eastern base of the Sierra Oscura there are several low ridges, remarkable for their red color. All of these red ridges contain reefs of copper-ore. The eastern flanks of the Sierra Oscura are composed of limestone. Some fossils in the limestone were examined by Prof. J. P. Smith of Stanford University, who says they are Fusulina and indicate an Tipper Carboniferous age. The sandstones and shales containing the copper-reefs directly overlie this limestone (Fig. I), and are very likely of Permian age, like the similar beds in Texas, described by Mr. W. F. Cummins.* Overlying the copper-beds are red sandstones and shales in which very little copper has been found. The cupriferous zone and the red sandstones and shales are everywhere associated, and as one stands on a high point, he will see that these rocks form three main belts or lines of hills. These may be referred to as the northern, middle and southern belts. The northern belt was not visited by me, but is known to contain copper-deposits. The middle belt has a trend of N. of W. and S. of E. The copper-reefs have been traced for a distance of more than 2 miles. The southern belt has a trend of about N. 30' W. and S. 30°

Jan 1, 1903

By H. T. Van Ells

The following is a brief description of the cost accounts in effect at the mines of the Anaconda Copper Mining Co. The accompanying chart, Table I., shows the distribution of labor, materials, and redistributable accounts to the various operating and repair accounts. OperatiNG. Development. Owing to the fact that every mine has its peculiarities in formation and methods, the question of arriving at what charges should be included under the head of " Development" is one that has occasioned considerable thought and comment, and in the cost sheet of the Anaconda Copper Mining Co. this account has been sub-divided to show the expenses of breaking ground, tramming, timbering, shaft sinking, up-raising, and cutting stations and skip chutes. It has always been the policy of the company to charge the entire cost of this work to operations monthly, whether the mines are producing or not, also the cost of the opening up of new mines; and only surface construction and additions are charged to capital, excepting original machinery installed for operating pumping plants. Explanations of the charges to the various sub-accounts follow : Breaking Ground.—Work performed in driving cross-cuts from the station, or cross-cuts from the drifts, and diamond-drill work, for the purpose of discovering or developing ore bodies. Tramming.—Cost of tramming waste produced by cross-cuts mentioned above. When waste is hoisted to another level to be used for filling, the charge to this account stops at the station, and when hoisted to surface the charge includes tramming from the collar of the shaft to the dump. Timbering.—Cost of timbering the cross-cuts mentioned above includes the cost of handling and framing such timbers, but does not include the wages of station tenders and top carmen.

Jan 1, 1914

By C. H. Pishny, Raymond M. Carr, E. J. Dickinson

Petroleum development in Oklahoma during the year 1932 was rather colorless. The crude price structure, while it was relatively stable, was too low to encourage wildcat drilling and proration restrictions were such that producing wildcats were usually faced with the drab prospect of being limited to 50 bbl. per day. Proration in flush and semiflush areas was for the most part successfully accomplished. Military enforcement of proration rulings was deemed necessary at Oklahoma City. The trend toward cost cutting and abandonment of unprofitable wells continued through the year. It is estimated that 1500 wells were abandoned and it is not unlikely that as many more were shut down which will never produce again. Oklahoma crude oil stocks were reduced by approximately 11 million barrels in 1932. It is generally conceded that inventories of material have been appreciably reduced. Leasing activity was limited principally to rental reductions and to close scrutiny of all lease holdings. There were numerous "leasing plays" based on geophysical information but with few exceptions they were small. It is estimated that over 15 per cent of the acreage under lease at the beginning of 1932 was surrendered during the year. There was a tendency through the year to prospect shallow pay sands formerly passed by in the search for deeper production. This is especially true of the Seminole area, where the Calvin sand received considerable attention, and where some good wells were completed. Prices There were two price changes during the year that affected the majority of crude sales. Using 36 gravity A.P.I. as a basis of comparison, the price was increased on April 11 from $0.77 to $0.92. On Dec. 16, the price dropped to $0.69. During the fall months there were several postings higher than this schedule but all postings were at the same level at the end of the year.

Jan 1, 1933

By Morris Cohen, William P. Kimball

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 (6) of the liquid-to-solid transfer at each temperature has been derived: d= Zlxl(xl - P) + Zsxs(P - xs)/Zl(xl - P) + Zs(P - xs) [1] where ZL and Zs are the slopes of the liquidus and solidus lines at the given temperature, Xl and 28 are the compositions of the stable liquid and solid phases at the same temperature, and P is the composition of the alloy under consideration. The 6 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. The d-versus-temperature curves for two alloys P1 and P2 are shown in Fig. I. In each case, the liquid-to-solid transfer has the same composition as the stable solid phase only at the temperature of the beginning of solidification, and has the same composition as the stable liquid phase only at the temperature of the completion of solidification. At each intermediate temperature, the composition of the liquid-to-solid transfer differs by a finite amount from those of the two coexisting phases. Therefore, during equilibrium cooling, the transfers must merge into the solid phase from the liquid without forming a transition phase; otherwise the condition of equilibrium would be violated. At any given temperature during solidification, the composition of the liquid-to-solid

Jan 1, 1941

By William P. Kimball, 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 (6) of the liquid-to-solid transfer at each temperature has been derived: d= Zlxl(xl - P) + Zsxs(P - xs)/Zl(xl - P) + Zs(P - xs) [1] where ZL and Zs are the slopes of the liquidus and solidus lines at the given temperature, Xl and 28 are the compositions of the stable liquid and solid phases at the same temperature, and P is the composition of the alloy under consideration. The 6 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. The d-versus-temperature curves for two alloys P1 and P2 are shown in Fig. I. In each case, the liquid-to-solid transfer has the same composition as the stable solid phase only at the temperature of the beginning of solidification, and has the same composition as the stable liquid phase only at the temperature of the completion of solidification. At each intermediate temperature, the composition of the liquid-to-solid transfer differs by a finite amount from those of the two coexisting phases. Therefore, during equilibrium cooling, the transfers must merge into the solid phase from the liquid without forming a transition phase; otherwise the condition of equilibrium would be violated. At any given temperature during solidification, the composition of the liquid-to-solid

Jan 1, 1941

ROBERT M. KEENEY,* Portsmouth, Ohio (written discussion?).- Mr. Coffin has written a most interesting paper that covers most of the uses to which water-cooled devices are subjected; but to meet with the operating department's approval, these devices must effect a saving in cost per ton of ingots produced in the furnace. The making of steel in the open-hearth furnace is dependent entirely on the personal element. It is not possible to charge the furnace with so much raw material, turn on a valve for heat, and by use of recording thermometers, clocks, etc. empty the furnace when a steel is made. Competent men trained to the work must be in charge all the time, and the quality and quantity of steel produced is quite as dependent on the care and working qualities of the furnaces as on the raw material and working of the charge itself. Steel making is hot, hard work and the inducement offered to technical men to take up this work is not sufficient to induce many to enter the field. The result is that most of the workmen in an open-hearth plant, the men who actually operate the furnace and make the steel, are not technical men and do not understand the "whys" and "wherefores " and care less. All this means that a furnace must be built as nearly fool-proof as possible. By this I mean that it is necessary to protect those parts of a furnace most subject to abuse by water-cooled devices whenever possible, and these water-cooled appliances must he as nearly fool-proof as they can be made. The control of the gas entering a furnace is of the utmost importance. This means a properly designed port must have the same design throughout the whole run of the furnace. This is not possible with the ordinary

Jan 6, 1919