Search Documents

By Richard Moldenke

In crowding the recent mass of work on the physics of cast-iron into the compass of a short review, I cannot do better than to follow the lines of Mr. W. R. Webster's suggestion, made at the Florida meeting of the Institute, March, 1895.' The classification of the properties of the metal, and the influences to which it is subjected during the various processes it undergoes, is quite complete; and as Mr. Webster gives it again in full in another paper at the present meeting, a simple reference to it now will be sufficient. I. Correspondence Between Chemical Composition, and Melting-Point, Fluidity, Shrinkage, Fracture,Chill, Micro-Structure, and Other Physical Properties. Melting-Point.—The melting-point of cast-iron had long been a subject of controversy among foundrymen. They knew that a hard iron melted faster than a soft one, but this effect was occasionally disputed, and the reasons given were unsatisfactory; but could not be well controverted. It was my good fortune to take the actual melting-temperatures of some 70 pig-irons and castings; the Le Chatelier pyrometer, suitably protected, being introduced into the interior, and the iron melted off in a specially-constructed cupola. The irons had been previously analyzed by taking the borings at the point of the intro-

Jan 1, 1905

For the first time, the attendance at the meetings of the Institute passed the thousand mark; as is shown by the following table: REGIS- AT BANQUET DID TOTAL TERED NOT REGISTER Men :..:... 703 76 806 Women 195 61 256 1062 The names of the members and guests who registered or attended the banquet but did not register are: A A. D. Beers C. A. Adams Hans Behr Thos. J. Adams Edgar G. Bell Lawrence Addicks Donald A. S. Bell H. T. Abrams W. de LeBenedict G. Aertsen G. B. Bertelli M. M. Albertson Charles P. Berkey James Aldrich Clinton Bernard D. C. Alexander, Jr. W. N. Best W. H. Alexander Robert M. Betts A. W. Allen Christopher H. Bierbaum F. D. Aller Paul Billingsley R. H. Allport R. A. Bingham F. C. Alsdorf R. M. Bird Capt. M. Altmayer John L. W. Birkinbine A.' W. Ambrose G. S. Bisey Henry M. Ami Charles W. Boise F. L. Antisell J. J. Blackmore R. S. Archer A. E. Blackwood Paul' Armitage Capt. C. K. Blatchly Andrew B. Armstrong E. L. Blossom Clifton T. Armstrong C. A. Bohn Ralph Arnold James M. Bonsall R. M. Atwater, Jr. E. E. Boon Joseph E. Aue Gail Borden A. M. Austin R. S. Botsford W. S. Ayres John M. Boutwell

Jan 4, 1919

C. R. CORNING, Chairman. ADOLPHE E. BORIE, First Vice-Chairman. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. Vie-Chairmen. JOHN H. ALLEN, GEORGE M. COLVOCORESSES, RICHARD M. ATWATER, JR., ROBERT PEELE, GEORGE D. BARRON, CHARLES P. PERIN, A. CHESTER BEATTY, JOSEPH A. VAN MATER, J. PARKE CHANNING, ARTHUR L. WALKER. D. C. Bard, Howard Eckfeldt. Philip N. Moore, W. de L. Benedict, R. C. Gemmell, T. H. O'Brien, John C. Branner, F. Louis Grammer, James J. Ormsbee. Palmer Carter, Ernest A. Hersam, Edward W. Parker, Allen J. Clark, Edwin C. Holden, John B. Porter, F. Crabtree, William L. Honnold, R. DI. Raymond, George G. Crawford, Reginald E. Hore, Robert H. Richards, O. C. Davidson, C. Colcock Jones, LeRoy Slash, E. V. D'Invilliers, Eugene P. Kennedy, Frederick H. Sexton, James S. Douglas, Chester F. Lee, Henry L. Smyth, Walter Douglas, Richard S. McCaffery, F. W. Traphagen, Howard N. Eavenson, James F. McClelland, Elton W. Walker. Milton H. McLean, The Chairman of the Committee on the eve of his departure frog -,he country for an extended stay, addressed the following letter t ,he President of the Institute NEW YORK, N. Y., APRIL 19, 1913.

Jan 5, 1913

JOINT convention week has become a feature of the year with western mining men. The first was held at Denver in 1926, the second at Salt Lake City in 1927, and the third is about to take place at Los Angeles. Holding in the same city in one week the meetings of a number of related organizations has been .found to permit the development of a well-rounded program at the same time that it economizes time and money for the members, many of whom belong to several of the participating organizations. For the third time, the American Mining Congress, represented by its Western Division, of which Philip Wiseman is chairman, is taking the lead and assuming the main responsibility. The A.I.M.E. is furnishing the papers for two sessions and the California Development Association for one. The Southern California Section, Robert R. Boyd, chairman, is host for the Institute, but the Northern California, Nevada and Arizona sections have each contributed papers to the program, and will be represented at the meeting. It will be a real reunion of the mining men of the Southwest.

Sep 1, 1928

By Bieniawski, Z. T.

The importance of understanding the phenomena associated with rock fracture has long been fully appreciated in rock mechanics. This is clearly apparent from the special attention paid to rock fracture in the comprehensive papers published within the past four years. These papers present a picture of how the knowledge of brittle fracture of rock was gradually enriched and also show that what was often taken for granted three or four years ago is no longer considered as valid today.

Jan 1, 1972

By SAMUEL GOMPERS

THE name engineer makes a very strong appeal to one who appreciates the mechanism underlying the fabric of our civilization. Engineers are scouts of civilization. We send them ahead into the lone 'places-the wilderness, the jungles, the great watery expanses, to build the highways necessary for civilized man. The engineers must deal with Nature, with that mysterious dynamic thing we call "force," with materials. It is their function to direct the human activity necessary to coordinate these forces and material in order to make them serve the needs and aspirations of men. Because of my high conception of the engineering profession I was glad to accept the invitation to address The American Society of Mechanical Engineers to voice my understanding of the possibilities of your work as engineers of industry, and to suggest what seems to me the responsibility of the-engineer to the whole modern industrial system.

Jan 1, 1921

Discussion of the paper of J. C. Febles, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 79, July, 191.3, pp. 1267 to 1283. J. W. RICHARDS,. South Bethlehem, Pa. :-In looking at these precipitating launders the idea has come to me that the iron could probably be kept much cleaner if there were laid on the bottom of the . launders some sheet copper, with which the iron would be in contact, and as the solution passed over the tendency would he to precipitate the copper on the sheet copper and thus keep the iron cleaner than it is under present conditions. As soon as a piece of iron becomes coated with copper, its surface becomes inactive, and the presence of a sheet of copper in electrical contact with the iron would tend to precipitate the copper on the sheet copper and to keep the iron clean.

Jan 11, 1913

By Clyde E. Williams

MORE has been said about the iron and steel situation on the Pacific Coast than has been done .about it; but perhaps as much has been done as conditions have warranted. The production of finished steel in an amount sufficient to take care of the local demand for certain sizes and shapes is an established industry on the .coast. The amount .and the variety of products, so made, changes with the demand or them which is largely dependent upon the growth in population. An increasing demand will not always increase the quantity of steel produced locally because the cost of production may rise so -high as to let in steel from the outside. The reason for this is that all of the steel made in the West comes from steel scrap, the supply of which is .limited. From the standpoint of the metallurgist, it would. be desirable to subititute pig iron for some of ' the steel scrap, but this cannot be done profitably because the pig iron now available is too expensive. In other words, the large future demand for steel and pig iron on the Pacific Coast must be supplied by reduction of ores in the West, unless we are to be content with paying high transportation costs for material produced elsewhere. ."

Jan 1, 1924

By Richard W. Smith

THERE are three distinct varieties of phosphate rock, in Tennessee, known commercially as: (a) the "brown" rock, which is the residual pro- duct of the weathering and natural concentration of certain phosphatic Ordovician limestones; (b) the "blue " rock, which is an unaltered phosphatic stratum of Mississippian or Devonian age; and (c) the "white" rock, which is the result of chemical replacement and deposition. Before 1894, South Carolina and Florida had supplied most of the phosphate of the United States, South Carolina leading until that date and Florida from then until the present time. In December, 1893, the blue phosphate of Tennessee was discovered almost simultaneously on Swan Creek, in Lewis County, by two independent parties-by one as the result of a careful and systematic search for a workable deposit of the long known kidney phosphate, and by the other through mistaking it for a "bloom" of coal. Leases were taken and, with further prospecting disclosing other deposits in the region, the development progressed as rapidly as 'could be expected without railroad transportation

Jan 1, 1924

By A. L. Volley

(Read at the Amenia Meeting, October, 1877.) THE existence of iron ore and anthracite coal in the neighborhood of Providence, R. I., has long been known, chiefly as a geological fact; that these materials, so near to each other and to tidewater, are of such a good quality and are present in such large quantity, as to have seriously raised the question of establishing blast furnaces there, was a surprising fact to me; and I have thought that the few notes I have lately gathered on the subject would be of interest at this partly New England meeting. The coal field referred to has an area of above 400 square miles, and is found throughout the belt of transition rocks extending from Newport Neck to Mansfield, Massachusetts. It underlies the cities of Providence and Newport, and the towns of Middletown, Portsmouth, Jamestown, Warwick, Barrington, Cranston, North Provi-

Jan 1, 1878

By F. H. Gilpin

SINCE Noah pitched his ark within and without with pitch, the use of asphalt in human endeavor has been increasing-for Noah's pitch was asphalt. Asphalt is a bituminous material found in nature, either pure or admixed with smaller or greater quanti-ties of mineral and non-mineral materials, or obtained by the refining of crude asphaltic-base petroleum under proper methods of control. Native or "natural" asphalts are scattered through-out the world, though the commercial value of the various deposits varies greatly, depending upon both their accessibility and magnitude and the quality of the material found. It is an acknowledged fact that such asphalts have been produced through natural causes by practically the same application of tempera-ture and pressure as are used in the modern refining of crude asphaltic-base petroleum. The best known of all the native asphalt deposits are those of Trinidad Lake in the Island of Trinidad, British West Indies, and of Bermudez Lake in Vene-zuela. Asphalt from Trinidad Lake, after refining to remove organic and some inorganic diluents, contains approximately 35 per cent, of inorganic residue, and the asphalt thus produced must be fluxed with lighter asphaltic or semi-asphaltic base oil to make it com-mercially utilizable. The refined asphalt obtained from the Bermudez Lake deposit contains from 4 to 6 per cent. of inorganic material which cannot be removed. This asphalt, also, must be fluxed to produce com-mercial products. Small quantities of similar materials are available in other locations. The best pure native asphalt' is known as. gilsonite and is mined in com-mercial quantities in the State of Utah. In numerous places in the United States, particularly Oklahoma and Kentucky, there are deposits of sand¬stone and limestone impregnated with bitumen, which are known as rock asphalts. These rock asphalts may be used, particularly in the paving industry, either as found or by slight fluxing; from some deposits the asphalt is extracted and marketed commercially.

Jan 2, 1923

By J. P. Witherow

MR. BIRKINBINE'S description of the bad working and sudden chilling of the Warwick Furnace last summer, seems to me quite phenomenal in blast-furnace practice. During my connection with the management of blast furnaces for many years, in the anthracite, coke, and raw-bituminous coal districts, such a case has never come under my notice. It seems to me that the scaffold in the zone of fusion could not have established itself (so that the whole power of the engines, with a blast pressure ranging from 12 to 18 pounds per square inch, could not penetrate), unless the furnace was previously badly scaffolded and bridged in some of its upper sections, from 15 to 30 feet above the hearth level, either in the zone of chemical action or the beginning of the zone of fusion. Such a "barrier to the upward gaseous currents would cause a suspension of combustion which may have superinducedd the scaffold that is assumed to have existed in the zone of fusion. It is Difficult to conceive' that an agglomerated mass almost across the section of the lower bosh should have formed all at once, if the furnace was free and porous for the reaction of the gaseous currents above. Therefore, I think, the Warwick furnace was by no means in as free, open, and fine internal condition at the time the trouble commenced as the description of its regular working would lead us to suppose. I do not question the accuracy of the statements relative to the output of iron, etc. I merely claim that the phenomena., as described, could not have been almost instantaneously developed, unless there had been an incipient seaffold and lodgment above the zone of fusion. I would state my hypothesis to be that the stock lodged or collected in some of its upper sections during the process of blowing-in, on which, as a basis, more or less accumulations may .have lodged, and thus, indirectly, caused the formation of the suc- * This paper was not presented to the Institute in its present form, but is based on remarks, in discussion, by the author on Mr. Birkinbine's paper on, a Short Blast at the Warwick Furnace, and Mr. Witherbee's paper on Two Scaffolds at the Cedar Point Furnace.

Jan 1, 1881

By Norman C. Stines

Russia's mineral potential is a secret that has been effectively kept by the Iron Curtain. There is no conclusive data and because of its extreme importance to the Free World, the subject is greatly discussed. Opinions range from those presented by Paul Tyler in his article "Russia's Mineral Potential," June issue of MINING ENGINEERING to those of Norman C. Stines, presented herewith. Mr. Stines is a consulting mining engineer of Los Gatos, Calif. He was in Russia, China, and Manchuria from 1909 to 1918 as a mining executive. From 1917 to 1919 he served as assistant military attache Intelligence Branch U. S. Army in Petrograd, Russia.

Jan 11, 1951

By Wayne E. Glenn

A centennial meeting should be a time to take stock, to evaluate performance, to plan ahead. It is like a line in a televised commercial that goes, "You've come a long way to get where you've got to today." And no less should be said of the mining and energy industries. We have come a long way. A hundred years ago when AIME was founded, this country produced 23 million tons of bituminous coal and 5.2 million bbl of oil. The figures in 1970 were about 580 million tons of coal and 4.1 billion bbl of oil. In spite of such accomplishments, serious and compelling voices are heard in the land - doubting sincerity, questioning corporate structures, and challenging ethics. Those doubts are raised in one part of Washington at the same time that other sections of the Capitol are asking us to produce more energy in order to keep up with population growth, emerging nations, and new technologies. Those of us in the fuel or energy business frequently talk about the race for energy. The question is, can we develop enough energy fast enough to outdistance our present and increasing demands? Recently I heard of an incident that - in an odd way - caused me to think of the energy race. The incident involved a sky-diver who jumped from an airplane without a parachute. He was handed a chute in mid-air by a sky-diving companion. He put it on, opened it, and landed safely. In a way, it seems to me that our society is hurtling through space and that it needs some help from the energy industries to land safely. We're doing our best, but under some rather difficult conditions. Because of illegal strikes and work stoppages the coal parachute is snarled a bit. The cut in percentage depletion and other tax changes have put some holes in the oil parachute. And the gas ´'chute has been in trouble for some time because of unrealistic controls on producer prices. The irony of the situation is that some of the very people who have been taking potshots at the energy parachutes for a long time are the ones who are complaining loudest now because the 'chutes are not functioning the way they could. The safety of the entire nation can depend on the energy industries.

Jan 1, 1971

WELL known member of the Institute, Henry Krumb, survived the Japanese earthquake and has written a most interesting description of his personal experience to a friend in New York, an extended excerpt from which we publish, by permission, below. Not having been written for publication it has increased value as a human document in its vivid description of personal impressions and sensations in the midst of such a catastrophe. The earthquake was the most terrible experience I have ever passed through. We arrived at Miyanoshita, Friday, Aug. 31, about 6 p.m., having left Yokohama about 2:30 that afternoon by automobile. It was a most beautiful ride, although rather warm, but not unusually so, as it has been uncomfortably hot ever since we arrived in Japan. The first part of this automobile trip was along the old highway from Kyoto to Tokyo, which is lined with fine old pine trees. There are 52 villages along this highway and we saw real Japanese country life: naked children, both boys and girls, and men wearing nothing but gee-strings. The country on either side was intensively cultivated, the green rice fields and lotus ponds making a most beautiful sight. The occasional hills were all re-forested with young pines. In places the road runs close to the ocean beaches. The last part of the trip was up a steep mountain road, cut out of the side of the mountain. On one side of the road, in the gulch below, was a roaring river. The road crosses this river several times. Miyanoshita is beautifully located on the side of a mountain about 400 ft. above this river at an altitude of 1400 ft. The grounds of the hotel are laid out in Japanese style, small lakes with fish, waterfalls and dwarf trees making a very pretty sight. On the morning of Sept. 1, after walking around the garden and the hotel, we went to our room and I started to write up a few notes. Mrs. Krumb was reading a guide book. A few minutes before noon she came over to the table where I was writing and said that it was about lunch time. Just at that moment hell broke loose. It was the first earthquake I have ever experienced and I did not immediately realize what was happening. The building was shaking as a mine office might shake when heavy blasting was going on near by. Mrs. Krumb, having experienced many earthquakes, stepped to the open door between our room and the bathroom and called to me to get out from under the chande-lier. The plaster was commencing to fall and a large wardrobe fell over. I then knew what was happening and ran to the win dow. Before I reached it a large chunk of plaster from the ceiling hit me on the head and cut my forehead and nose. Mrs. Krumb ran for the other window just as the marble mantelpiece and the dresser fell. Without any hesitation, she jumped out of the win-dow and I followed suit out of the other. Luckily neither of us sprained an ankle-we had jumped 8 ft. We started to runaway from the building but had not gone more than 25 ft. when a second shock or rather a continuation of the first became so violent and the ground under our feet was trembling so that it was almost impossible to stand up without holding on to a tree. The ground seemed to have become liquid and rocked violently, it seemed to me in a vertical direction. In some later shocks the movement was more horizontal. About this time Mrs. Krumb saw the blood on my face and commenced to break down, but only for a moment: As soon as she saw it was not serious she was all right and during the following days stood the experiences and hardships as well as the best of them:

Jan 11, 1923

ZAY JEFFRIES, Cleveland, Ohio (written discussion?).-The authors conclude that there is a certain average size of precipitated CuAl2 par-ticle which produces maximum strength and hardness in duralumin; that when the size of particle is smaller or larger than this particular size the hardness decreases. The writer agrees with this conclusion, because it seems to he directly indicated by the facts. Why does duralumin present this apparent discrepancy? Let us con-sider some physical aspects of the precipitation of CuAl2 from a saturated solution on cooling. When a molecule of CuAI3 is removed from the solvent, or matrix, and added to another group of CuAl2 molecules, as is known to occur on slow cooling, the forces of adhesion between the CuAl2 molecule and the solvent have been exceeded. Since a. change in tem-perature only is sufficient to cause precipitation, it must also be sufficient to cause the loss of adhesion bonds between the excess CuAl2 molecules and the solvent, or matrix. Lost adhesion bonds means loss of cohesion of the mass as a whole. When duralumin is cooled from 500° in a furnace, globules of CuAl2, large enough to be seen easily with a high-power microscope, are formed. There are, however, globules so small as to be hardly distinguishable, and others too small to be resolved are suggested by the non-uniformity of the surface appearance of the section. As the smallest globule of CuAl2 resolvable with a high-power microscope contains about 2,000,-000,000 molecules, it is evident that with rapid cooling submicroscopic particles of CuAl2 must be present in large numbers; in fact, after quench-

Jan 12, 1919

By Max Roesler

W. L. CUMINGS,* Bethlehem, Pa. (communication to the Secretary+). -In this discussion of Mr. Roesler's paper, I shall follow Kemp in using the term "granite" to refer to the acid rock called syenite by Kimball. Diorite, as I understand it, is the dark basic rock invariably closely associated with the orebodies. The types of rock of intermediate composition, mainly intrusives, are not under discussion. It is difficult for me to conceive that this granite is the ore-bearing agent, for the following reasons: 1. No isolated orebodies in the granite are known. It would seem that if this rock is the mineralizer, some small bodies, or at least patches and small masses of ore so situated would exist. 2. In 1909 the writer conducted explorations on the Pequena and Grande claims about 1 mile north of West Mine No. 5. This work was done after a very careful magnetic survey had shown a large and uniform area of attraction. As exploration progressed, it became evident that in this case the magnetic attraction was due to disseminated magnetite. Much ore of 40 per cent. Fe was found, but very little commercial ore was shown up. This ore was entirely in the diorite and no granite outcrops are near. The occurrence could easily have been described as "ore formation but very little ore." I cannot conceive how a remote granite intrusion could impregnate a diorite mountain with 40 per cent. of Fe, and prefer to believe that this 40 per cent. of iron was in its real home, rather than in a sort of dioritic "boarding house" after having been evicted by granitic parents. 3. The Ocaña mine, which has produced nearly 500,000 tons, shows no evidence that the granite is the mineralizer. This is admitted by Mr. Roesler on p. 1827. 4. I believe it will not be disputed that all the iron-ore deposits extending along the south coast for 60 or 70 miles are of a similar origin. Evidence available at other points might properly be referred to in discussing the article under review. At the La Plata mines, about 60 miles west of Santiago, the writer has also made explorations. No granite is in evidence. At one point in the bed of a creek is a small body of magnetite about 10 ft. long, entirely surrounded by a hard fresh diorite. To me

Jan 3, 1917

By Casimir Constable

DURING the years 1875 to 1879 I had charge of the Rockwood furnaces and mines, situated forty miles from the nearest railway communication at that time, and one hundred miles north of Chap tanooga, Tenn., by the Tennessee River. The small furnace with old-fashioned stoves, then in blast, was built under great difficulties by General Wilder. The early conditions were somewhat as follows: The ore was fossil ore of the Clinton group ; very fine and generally wet, without other admixture. The coke had a large amount of ash, and the fur" nace appeared to be badly scaffolded at times. On many days only a few tons of iron could be obtained. The founder generally id creased the revolutions of the engine when signs of chilling appeared,. The cinder at such times was black, very scoriatious, often closely resembling mill cinder. When the pressure was increased (the joints being the old-fashioned rust joints), leaks in the blast-pipe occurred It was noted that when the blast was stopped, and the leak bolt imperfectly remedied, the furnace improved a little. This set me thinking on the right track; and I took the responsibility of be coming my own founder for a time. A scaffolded condition had existed, and the situation was a trying one. Strange to say the negroes proved excellent furnace-men. Conceiving the hearth of the furnace to be similar to the grate area of a steam-boiler, capable of disposing of but so much fuel per hour, and requiring only a corresponding amount of air, it follows that an excess of air will burn the fuel not yet arrived at the hearth!, and raise the melting-point far above the tuyeres. This might pro duce scaffolding or at any rate choke the boshes, and leave less fuel to be consumed in the hearth. Thus for the time being less ail;. would be needed, as the continued burning of fuel in and above the boshes, would only aggravate the trouble. This condition of affairs accounted for the black cinder; the heat above having melted ore not yet perfectly reduced. This view decided me to reduce the revolutions of the engine; thefurnace finally became gray, as might have been expected. Any attempt to increase the speed produced black cinder and hard iron ;

Jan 1, 1883

The ventilation of metal mines is becoming more of a fundamental requirement than it was 10 or even 5 years ago. There are many reasons for this, and in general they are based on economy or efficiency rather than health or safety, yet the latter enters into the picture in at least some instances. One Montana metal mine which had installed mine fans and a general ventilating system shut down the fan when there was a period of cessation of work; within a few weeks it was found that the underground timbers were becoming so covered with fungus that the fans were put into operation and thereafter continued in operation whether the mine was worked or not. The fungus soon disappeared and the cost of operating the fans was held to be far less than would be the numerous losses from timber decay which quickly started when cessation of air flow was encountered. A large iron ore mine in Michigan had much difficulty in holding men in a slicing region due to foul air under certain surface conditions as to direction of wind. Upon the placing of a moderate sized fan on the surface with some doors, stoppings and regulators underground, not only was the bad air condition removed but there was found to be a decided increase of tonnage per man per shift and timber decay was retarded to a very considerable extent. This particular mining company was rather inclined to be angry when I called attention to some of the what I considered very bad working conditions underground, and the mine superintendent for about a year and a half was on anything but friendly terms with me. Later on when the effect of the placing of the fan was found (the fan had been placed over his protest), that, man came through very nicely with a letter and congratulated me on the recommendation made and congratulated himself and the company on the conditions obtained after the installation of the fan. Poisonous Fumes after Blasting A copper mine in the Southwest with an ore of a high sulfide content has much difficulty due to poisonous fumes after blasting, and the, fan installation is as elaborate as those of many of the most nearly up-to-date coal mines, and coal mine splitting and regulating practices are being

Jan 1, 1927

By Thomas Egleston

The uncertainty of finding the exact equivalents fortechnical expressions in different languages has led me to think that a glossary of furnace-terms would be useful to members of the profession. I was led, some years ago, to prepare a small one, which has been found so very useful, that I have arranged one for presentation to the Institute, for four different 'types of furnaces, in the hope that it may prove of use to those who are in the habit of consulting foreign technical journals, I was further induced to make the attempt in the hope that it might tend to make the terminology less complicated than it now is, and also to make it more uniform over larger districts. The idea of referring to a drawing which expresses exactly what is meant, resulted from the necessity of presenting such subjects to students, and will, it is hoped, prove much more useful than the mere dictionary arrangement in alphabetical order. The drawing of the blast-furnace was prepared for me by Mr. J. P. Witherow, of Pitsburgh ; the drawing of the open-hearth furnace by Mr. S. T. Wellman, of Cleveland, and the reverberatory furnace by Mr. John Fritz, of Bethlehem. The bloomary-furnace is taken from my own paper* on Bloomaries, but, in order to have a complete furnace, I have introduced into the drawing of those used at Saranac the guard-plate used at Ironville. The interest which has been taken in the preparation of this paper by those gentlemen who have contributed the drawings, has been supplemented by gentlemen in Europe who have taken the trouble to read the proof. In France it has been read by Mr. Lodin, of the School of Mines, and by Mr. Chaper, of Paris, and in Germany by Dr. Wedding, of Berlin, and Mr. Luhrman, of Osnabruck. The preparation of the paper has been much more difficult than was anticipated, and its value has been very much enhanced by Dr. Raymond's kind assistance and cooperation; and to him, as well as to all the other gentlemen, Iam very much indebted. It was at first proposed to add to the paper the names of all the tools used in these various furnaces. It was found, however, that this would make such

Jan 1, 1888