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By W. R. Jones

composition, he cannot reasonably asl; the manufacturer to guarantee that this composition shall give certain physical results. W. R. Jones, Pittsburgh, Pa. : The question that naturally occlun to me is this: Has Dr. Dudley in his inveatigtrtions been aiming to prove a theory, or has he been guided by an earnest desire to discover what are the proper elements in the composition of a good-wearing steel rail ? Unfortunately, for correct chemical information, he has omitted in his analgw two very importnat elements,—sulpbur and copper. Now, before we will even begin to admit the correctnets of Dr. Dudley's conclusions and the formula he prescribes, we will at the start question the propriety of any chenlist or scientist prescribing a formula for making steel when he has iguared such important ele ments as sulphur aud copper. I, for one, will not accept any such formula. Are we sure, or is Dr. Daclley sure, that the chemical analyseq embodied in his paper are correct? This may seem a presumptuous queetion, yet, with my experience with chenlists, I naturally doubt the correctness of the analyse8, and, before I will accept them as correct, I will ask that comparative tests of phosphorous and man ganese be made by the Pennsylvania Railroad chemists and the chemists of the leading steel-works in the country. Let us first verify the correctness of the analyses before we consider the con clusions. I can enumerate a great number of instances in which chemists have differed very widely in their determinations of phos phorus and manganese. A prominent iron fitam made a contract with the Edgar Thomson Steel Company to deliver pig metal guar anteed to be between 0.07 and 0.08 phosphorus; an analysis by our chemist resulted in phosphorus 0.148 and 0.152,—a rather startling difference! Again, a sample bar of steel, in which our chemist reported phosphorus 0.11, was tested by a chemist of au other Bessemer works, ana his determinations were phosphorus between 0.07 and 0.08: A leading engineering establishmeut of Pittsbdrgh bought iron claimed by a chemical analysis to contain 0.08 phosphorus; our Mr. Ford found phosphorus 0.145. A chem ist connected with an open-hearth works reported manganese in a piece of steel, 1.14; in a second determination from the same piece of steel, by the same chemist, manganese was reported 0.43. The chemist was kept in ignorauce of the fact that both samples were from the saw piece of steel. Two dctermiuations for manganese

Jan 1, 1881

By Rich Akerman

as 1866, I wish to assure both these gentlemen that I had not seen the section when I designed mine, :md even if I had, I should not have then dared to put it forth as a standard for English rail makers; tind the soundness of my opinion has a simple but conclusive proof in the statement made concerning the extra price which was at that time required for their production. I need not say that I highly approve of the original Welch section, for it is in principle similar to the design which I made ufteen yeam subsequently; and from a professional point of view I would fully concecle to Mr. Welch the credit of first designing the modern steel-rail section. From com- mercial, matter of tict, and practical point of view, he was, however, before his time by many years; or to put it in another way, rail making was ten years behind its time when the new metal steel was first introduced for rails. If his design has been incorrectly identified with my name (as the sections are similar in principle, though they differ in thickness of flange and web), I beg to say (1st) that I much regret the misun- Understanding which has arisen through no fault of niine, aud (2d) that no confusion has been intentionally created by me. It is a pity that the section designed so long ago has not been made public at an earlier date, as it would make a really goal stand- and pattern, anil even now be quite equal to present requirements. In conclusion, I wish to say that I have never desired to claim any invention or novelty by the publication of my sections; they Were put forth as being such as English railmakers could and would produce at the ordinary market. price, and as being the best and most suitable to be so obtained. Had Mr. Welch or Mr. Holley put forward theirs ten or fifteen years ago, I should have been the first to recommend theru. In fact I should have been glad to see their narnes associated with rail patterns in their own country, in the same way as mine has been. PROFESSOR RICH. AKERMAN, STOCKHOLM, SWEDEN: i AGREE with your (Mr. Sandberg's) views that it is too early yet to stipulate only one definite chemical composition in the rails. Such a stipulation, I think, might he justified, if it were not for the manganese; but this metal changes the properties of the iron aud steel in tho same direc- tion ae carbon, silicon. and phosphorus, by increasing its tensile strength, stiffness, hardness, and brittleaess. If the iron and steel does not only contain carbon and manganese but also phosphorus,

Jan 1, 1881

By Edmund C. Pechin

The Lucy furnace, owned by Messrs. Carnegie, Kloman & Co., and located on the Alleghany River, on the outskirts of Pittsburgh, is a splendid modern furnace, 75 feet high, and 20 feet bosh. She had been working well on low grade ores of about 50 per cent., producing daily 68 to 75 tons. There was on stock 500 tons of Republic ore, one of the purest and best of the Lake Superior ores, averaging over 68 per cent. of iron, which had been procured for the purpose of making a trial for Bessemer iron. This was charged by itself, and Mr. Skelding, the founder, reports that he did not succeed in getting a single cast when it came down, before the furnace chilled from the hearth to the top of the boshes, some 25 feet. Every effort was made to save her, without avail, and the disagree-

By C. P. Karr

For several years, the Bureau of Standards has been working in cooperation with an Advisory Committee on non-ferrous metals on various phases of the production and testing of zinc bronzes. The work has dealt especially with the type of metal known as "Admiralty bronze" in England and as "Government bronze" in this country and consisting of 88 copper, 10 tin, and 2 zinc. Several reports have been made on this subject and these should be considered in connection with this paper.' First Series of Five Foundry Tests A very brief summary of the first series of five foundry tests has been made12 but for the sake of clearness the results are given here in different form. The five foundries cooperating in this investigation were: Ohio Brass Co., Mansfield, Ohio; Titanium Alloy Mfg. Co., Niagara Falls, N. Y.; Packard Motor Car Co., Detroit, Mich.; National Cash Register Co., Dayton, Ohio; Bureau of Standards, Washington, D. C. The object of the work was to determine whether uniform results could be obtained with this alloy in different foundries working under definite instructions. One of the participating foundries prepared, from virgin metal, a stock of ingots of the composition 88 copper, 10 tin, 2 zinc, and at the same time poured nine test bars from this melt of virgin metal. The results of the physical tests of these bars are shown in Table 1. Examination of this table shows that the highest and most nearly uniform results were obtained when the virgin metal was cast flat in chill molds and the lowest and- most variable results were encountered when it was cast, vertical in green-sand molds. In this, as in all other tables, the mean deviation was obtained by the usual method of taking the average of the differences of the individual values from the average values.

Jan 1, 1921

By C. F. Smart

The heat treatment of the bronze composed of 88 per cent. copper, 10 per cent. tin, and 2 per cent. zinc, has been investigated by H. S. and J. G. S. Primrose,' and also by the U. S. Bureau of Standards.2 The results obtained by H. S. and J. G. S. Primrose on dry-sand castings subjected to reheating followed by air cooling, or by quenching in water, are shown in Figs. 1 and 2. The values for tensile strength have been converted from tons per square inch to pounds per square inch. Figs. 3 and 4, have been plotted from values obtained by the Bureau of Standards on material of the same composition and treatment. Both investigations show that the ductility of the cast bronze is improved by heating to 700' C. and cooling in air, the strength not being impaired by this treatment. They are not in agreement, howevcr, as to the effect of quenching, Messrs. Primrose reporting a decrease, and the Bureau of Standards an increase, in both strength and ductility when the cast bronze is heated to 600' or 700' C. and quenched. The present investigation was undertaken to study the effect of annealing followed by different rates of cooling, and, in particular, the

Jan 1, 1921

By F. E. Bash

Previous to the war, this country depended on Europe for its supply of a number of alloys of great importance in the manufacture of electrical apparatus and equipment. When this source was cut off shortly after the beginning of hostilities and the small stocks in the United States were exhausted, either inferior substitutes had to be used or the manufacture of the apparatus suspended. Since electrical equipment was of primary importance in the prosecution of the war, the substitutes had to be used until the composition and processes of manufacture of the alloys could be determined. Included among these alloys was one generally known as manganin, which is composed chiefly of copper and manganese and which, beside having a low-temperature coefficient of resistance, has a low thermal electromotive force against copper. These qualities make it valuable for the manufacture of electrical instruments and machines in which it is used in the shape of wire, rod, and strip. As a result of these circumstances, an investigation was started to determine how manganin could be made on a commercial basis so that a product of uniform quality and the necessary electrical characteristics could be produced. The object was to procure an alloy with temperature coefficient of resistance not greater than 1 X 1X per " C. and a thermal e.m.f. against copper no greater than that of the imported material. It is characteristic of manganin that the temperature-resistance curve is not a straight line but has a peak, which varies in position with different samples; it is most desirable, however, to have it at a temperature of 25' C. if possible. The coefficients of manganin from all records available ranged from a large negative to a large positive value. The composition as reported by different authorities is given in Table I. Prof. Matthew A. Hunter, of Rensselaer Polytechnic Institute, made up a number of small melts of manganin in a graphite crucible and the one that he reported as having the best cocfficient gave the following analysis: Copper, 83.6 per cent.; nickel 2.5 per cent.; manganese, 13.6 per cent.; iron, 0.3 per cent. An analysis of a sample of German manganin gave the following: Copper, 82.6 per cent.; nickel, 3.8 pcr cent.; manganese, 12.8 per cent.; iron 0.7 per cent.

Jan 1, 1921

By R. H. Richards

The spitzlutte, as described by Rittinger, is an instrument by which saud is sorted in a continual upward-flowing stream of water. Its usual firm is that of a pointed box, placed with the point downward, the box receiving. its feed of sand and water on one side and discharging its tailings on the other. The sorted product or concentration is discharged at the bottom, at the apex of the box, through which it falls against an upward current of water, which current serves to effect the sorting and separation. To make this exposure to the quicksand condition still more effective, an inverted dam is placed across the spitzlutte, which forces the sand in its passage from the feed side to the discharge to pass clown into the more active portion of the upward-flowing current of water. In the form adopted for small tests in the mining laboratory of the Massachusetts Institute of Technology (see accompaaying sketch) the feed is'throogh a central funnel instead of being at the side, and the apex of this funnel, extending down nearly to the apex of the cone, talks the place of the inverted dam in the large spitzlutte. To keep the experiment perfectly under control a bulb or bottle is attached by a rubber connecting-tube to receive the concentrations, and between this bottle and the apex of the spitzlutte is placed a glass tube of conical form, with a side tube for' the admission of water. By regulating the admission of water through this tube the concentration may be allowed to go down into the bulb as fast or as slowly as the richness of the ore seem.; to demand. This spitzlutte may be used on products that have been previously sized to take out the heavy mineral. As an example of this a test was made upon a sample of ore where the galena, blende, and quartz were much mixed up, but separated fairly when crushed. The sample of ore was from Newburyport, and assayed 16.61) per cent. lead.. After sizing through a series of sieves the ore yielded conceutrations and tailings to the spitzlutte as follows :

Jan 1, 1881

By Thomas M. Drown

ZING is, as is well known, very brittle at a temperature of about 210' C. (410' F.), and may then be readily pulverized in a mortar. By sifting it may be obtained of uniform grain. I have been accustomed to prepare products passing through 40, 60, and 80-mesh sieves, and also by bolting through a fine handkerchief. The principal analytical uses to which I have hitherto applied this material are to the reduction of iron directly from the ore by heating it with the pulverized zinc, and the reduction of ferric to ferrous compounds in solution. In the first case the pulverized ore, 0.5 gram or less, is intimately mixed with about ten times its weight of the pulverized zinc (the finer the zinc the better), in a porcelain crucible, and this mixture is covered with about the same amount of zinc. The crncible is then heated at the top of the flame of a Bunsen bhrner, at a dull red heat, for about ten minutes. The crucible should not be covered. When cool, the crucible, with its contents, is placed in a flask treated with hot dilute sulphuric acid, and brought quickly to a boil. The zinc and reduced iron are dissolved in a few minutes and the flask is then tightly corked and allowed to cool. When cool, the iron is directly titrated by potassium permanganate.

Jan 1, 1879

By Charles O. Thomson

When a wire rod of iron or of steel is immersed in a hot solution of common salt, allowed to remain long enough to bring the metal to the temperature of the brine, and withdrawn, the surface of the rod is irregularly covered with a deposit of crystals of salt. These crystals adhere to the cod with great firmnes, in consequence, doubtless, of a thin film of ferric hydrate, which is formed between them and the rod as the water dries off. The rod can now be reduced, by successive passes through a dic or draw-plate, without any

Jan 1, 1881

By E. F. Loiseau

Until June, 1868, it had not been attempted, either in this country or abroad, to manufacture by mechanical means, from anthracite coal-dust, artificial fuel for domestic use. Several attempts had been made to utilize coal-waste by converting it into a fuel for manufacturing purposes, but none of the processes were original, and they were merely applications of the well-known European processes and machinery, slightly modified by American ingenuity and mechanical skill. With one exception all those attempts have been failures. The great difficulty in the application of European processes and machinery has always been the limited production, and the excessive cost of the manufactured product, as compared with the cost of mining and preparing the ordinary anthracite coal for the market. The only serious and intelligent attempt to manufacture, on a large scale, artificial fuel for manufacturing purposes, has been made by the Anthracite Fuel Company, whose works are erected at Fort Ewen, near Rondout, New York. This company, organized under the auspices of the Delaware and Hudson Canal Company, had to go through the usual course of difficulties, breakages, and disappointments, which seems to be the lot of every new industry. Thanks, however, to the energy and perseverance of Mr. L. L. Crounsse, a gentleman of means, from Washington, D. C, the enterprise succeeded, and it is to-day established on a permanent basis. In order to increase the production, and to reduce its cost, the Anthracite Fuel Company was compelled to change most of its •plant, and to erect more powerful machinery, producing lumps of a larger size, almost twice the size of the lumps made previously by the same company. This increase in the size of the lumps has been resorted to in Europe as well as in this country, in order to increase

Jan 1, 1879

By Charles A. Morgan

The proms of mire drawing depends upon the property which certain metals possess, termed ductility, which is defined in Brande's Dictionary of Science as a property inconhequcnce of which metals may be drawn out at length wilhotit interrupting the continuity of their constituent parts. As ticfincd thy M. Tresca, it is the property of flowing when subjected to pressure, and ie termed by him the "flow of solids," in his paper, read before the AcaiXemy of Sciences in Paris, November, 1866 * In the simple language of the wire shop, it is that quality in certain metals that thcm to be drawn (or etretched) out througl~ a tapering hole in a metal block or die, the die being more dense and harder than the metal to be redud. It is a fact well known to tllose slrillet1 in the ai*, that to eu~xeed in drawing iron or steel wire, it is of' the utmost, importance to have tborough lubritatiun, as a lack of it woullii udu-se abrasion of the wire, or of the walls of the tapering hole in the dia or plate, and quickly put an end to the operation. In drawing coarse or large sizes of pire, say & inoh diameter, the pressure upon the sides of the tay~dng hole, where the wire comes i.u contact with the die, so great that an ordina,y labricaot is equeezed out when the nsoal rc~luctions iu size are matie, and abrasion takea place. In order to meet this diffic:ulty, and emure proper lubrication, it has been a ccmmon prtictice for yazrs to apply a paste made of rye or wheaten flour, or lime, to the surface of the wire to be drawn, and when the pnstc is dry, to smwr tl~e wire with tallow or grease; the wire is then ready to be draw, the dried pa serving fo prevent the lubricant from being presetf out in the prows. Some years since, when Bessemer metal came iargely into use material for wire, 'the writer fourid that its dmwing requid so much more power than iron wire, that he was led to institute a. series of trials to ascertain the difference in power required. It was fotind that Bessemer wire requircd from 100 to 200 per cent. more power to makc the same reduction in sizes than soft iron wire, the difference depending npou the amount of carbon and other chemical constitu-

Jan 1, 1881

By William P. Shinn

Jan 1, 1881

By Charles M. Rolker

The Mariposa estate, a grant made by the Mexican Government to Juan 13. Alvarado, during the time when California was still under the dominion of Mexico, was purchased in 1847 by J. C. Fremont, and the United States patent issued to him in 1856. By sale, or its equivalent, money advanced, the property came into the hands of the Mariposa Company, June 25th, 1863, and through a varied existence of work and temporary inactivity, has as yet been kept as an undivided property, and rests at present with the Mariposa Land and Mining Company of California. I pass over this period of 15 years without giving the history of the ups and downs of the estate, partly because it is familiar to many, and also because I think in such a case this paper would assume too much the character of a narrative. The estate is situated in Mariposa County, California, about 170 miles southeast of San Francisco. It begins in lat. 37' 26' 38'' north, and long. 119' 55' west, and runs 6 miles north; thence 69 miles west; thence 5 miles northwesterly towards the Merced River; thence 84 miles southerly; thence 3 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 2 miles southerly; thence 2 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 1 mile northerly, and thence 2 miles easterly to the place of the beginning; embracing 44,387 acres (70 sq. miles) more or less. To describe this vast estate in detail as to its full geology, its numerous quartz veins, its many facilities to exploit them and work them by cheap methods, would lead me further than I intend to go at present, and I will content myself to describe the latest workings of the company and its immediate field of operations. As long ago as 1860 the late Dr. Adelberg advised the running of an adit from the northwestern edge of the estate at Benton Mills 011 the Mereed River. His object was to undercut the deepest workings of the then paying mines on the estate—the Pine Tree and Josephine. Following this advice, the tunnel known as "River Tunnel " was commenced. Its entrance is in S. 5, T. 4, s. R. 17 E. It is run in

Jan 1, 1879

By T. F. Witheree

The Fletcherville Furnace was built in 1864 and 1865, making its first blast from August until October of the latter year, when it was blown out to prevent its " bunging-up." Repairs were made in time to enable it to be blown in again December 12th, 1865, the blast ending October 7th, 1866. Total product 1921.15 tons iron, an average of 6.8.2.5 tons per day, from ores yielding 44.8 per cent. Consumption of charcoal 223.2 bushels per ton of iron. The furnace journal up to this time shows no record of furnace dimensions, or temperature of the blast, but as near as can be ascertained, they were as follows, viz.: Height of stack, 42 feet. Diameter of bosh, 11 feet. Angle of bosh, 71/2 inches to 12 inches rise, about 58°. Diameter of open tunnel head, 42 inches. Number of tuyeres 3 ; each 3 inches in diameter. Dam 15 inches high. Tuyeres 24 inches high. Tymp 224 inches high. Diameter of steam cylinder, 20) inches. } Diameter of blast cylinder, 64 inches. } Stroke 5 feet. The engine is direct-acting horizontal non-condensing. December 26th, 1866, the furnace was again put in blast, having been considerably altered in the crucible; the height of stack, bosh, and tunnel head remaining as before. Six tuyeres were put in, three in each of the side arches. The hearth or crucible was rectangular in form, 3 feet wide x 31/2 feet long x 64 feet high. Inclination of bosh 58°. Height of tuyeres 26 inches; nozzles 21/4 inches diameter. Temperature of blast estimated to be about 500°.

By Hon. Abrams S. Hewitt

Gentlemen : If my first words were other than those of thanks for the high honor of being called to preside over the American Institute of Mining Engineers, I should do injustice alike to you and to my own sense of the obligation, under which I have been placed by your voluntary choice. When the position was first suggested to me, I resolutely declined to allow the use of my name, on the ground that, by training and occopation, I was not entitled to this honor, which, it then seemed to me, should be conferred only on a professional engineer. In fact, the history of the Institute, which had honored itself, as well as my distinguished predecessors, David Thomas, Rossiter W. Raymond, and Alexander L. Holley, by elevating then] to its highest office, seemed to indicate the line and the limit of safe precedent, in which I did not then see how I could be included. But my scruples were finally removed by the consideration that, as in the course of human industry, the pioneer, of whom Mr. Thomas was so marked a type, must precede the mining engineer, so fitly personified in Dr. Raymond, and be followed by the mechanical engineer, whose incarnation we behold in Mr. Holley; so all these must be supplemented by the man of affairs and finance, in order that "enterprises of great pith and moment" may be prosecuted to a successful issue. I felt, therefore, that I had no longer any right to resist your preference, or to deprive myself of what I must regard as the crowning honor of an active career. On an occasion like the present it seems appropriate to review the history in this country, during the last hundred years, of those industries which the Institute of Mining Engineers specially represents. There is much in the story with which other members of this body are more familiarly acquainted than myself; yet I fancy that to all of them, and not less to our distinguished and most heartily welcome gnests from abroad, a comprehensive outline of the progress of mining and metallurgy in the United States mill prove interesting. I ask your attention, therefore, to a condensed account of that subject, embracing a statement of the beginnings of the industry on our shores, of the notable events attending its increase, and of its present

By Persifor Frazer

I DESIRE to say that, owing to the number of papers which have been more or less crowded at this session of the Institute, and the fact that, as one of the Local Committee, I have the distinguished honor to feel somewhat like one of the hosts, I should not tax the patience of members at this late hour, but would have my paper read by title were it in any way possible to do this. But the task I have set myself this evening is to present to the eyes of the members of the Institute certain objects which have occupied more or less of my time during the last eighteen months or two years. The objects I allude to are some of the igneous rocks of this country, which, until quite recently, have been less understood than any others. It will be well known to some of the members that some of the cooled lavas of a previous age of our planet, when not directly coarsely crystalline and granular, were considered and spoken of as " natural glasses," or perfectly uncrystalline, vitreous, or hyaline masses of matter. Among the first results of the use of the microscope was the dispersion of this fallacy. Sir David Brewster, Mr. H. C. Sorby, and William Nichol (the discoverer of the celebrated calcite prism, which bears his name), had, with greater or less success, examined sections of various rocks and minerals, both by transmitted and reflected light, and also in the form of powder. But, until the genius of Vogelsang undertook the subject, these investigations had no permanent value, nor did they constitute an independent line of mineralogical and geological research. Since the close of his labors, by Vogelsang's premature and much-lamented death, the subject has been made one of renewed interest by his brother-in-law, Ferdinand Zirkel, as well as by Rosenbusch, Tschermak, and many others abroad, and at home by the commencement of a systematic study of the traps of Connecticut by Messrs. E. D. Dana and G. W. Hawes, of New Haven, and by the splendid set of described sections of the traps of the West which have been furnished by Zirkel to illustrate Clarence King's report. I had the honor of presenting a large number of thin sections of our traps at the Washington meeting, for the inspection of the members, with the aid of a table microscope belonging to the Smithsonian Institution. Here I propose to project these sections upon the

By Lewis A. Riley

I desire to submit, for the consideration and information of the members of the Institute, the following data, drawings, and tables, showing what I believe will be interesting information with regard to the diamond drill, and its uses in developing mineral lands. I would first say that the results given have been obtained during the past two years by means of two drilling machines belonging to the Lehigh Valley Coal Company, operating on their coal lands in the Mahanoy, Lehigh, and Wyoming regions. 1st. A tabulated statement, giving location of borings, date, progress, total cost, itemized cost per foot, etc. 2d. Section showing strata bored in Nos. 5 and 10 holes at Mt. Carmel, see Plate VI. 3d. Section showing strata bored in No. 19 hole at Hazleton, see Plate VI. 4th. Photograph and description of drill No. 2. From the first it will be seen that the total number of test-holes bored up to May 1st of this year is 24; 9 of these are in the Mahanoy region, 6 in the Lehigh region, and 10 in the Wyoming region, in all of which cores have been taken for the whole distance. The total distance bored is 9902 feet. The majority of the holes have been put down for the purpose of proving the lower veins of the coal series, and have had to encounter the harder rocks of the coal formation. Much of the distance has been through the lower conglomerates, going in some cases through the coarse egg conglomerate, the foundation of the coal deposit, and to the green sandstone and red shale which underlie it. These lower sandrocks and conglomerates are among the hardest known to geologists, and present a formidable resistance to the exploring drill. This fact must be taken into consideratiotl in comparisons of cost of drilling, and when considered will still further improve the very favorable results I am able to show in my statement of costs. In illustration, I will cite the work of one bit when boring in the upper or softer rocks of the Wyoming region, where 280 feet were obtained without resetting, while in the Lehigh and Mahanoy regions, in the lower and harder rocks, bits set with the same quality of diamonds would only bore from 3 to 20 feet before being worn out. In this connection it may

By W. S. Ayres

By Adolph Henry

The manufacture of wheels of metal for locomotives and cars constitutes an important branch of the iron industry, and one closely related, moreover, to many of the conditions of railway practice, such as speed, safety of passengers, and economy of working. It has been, also, since the introduction of iron roads, a subject of constant study on the part both of engineers of construction and iron manufacturers. The car-wheels at first used in Europe had spokes of wrought iron and a hub of cast iron. Subsequently endeavors were made to make the wheels entirely of wrought iron, by forging successively the different parts which constituted the hub, spokes, and rim. By this treatment the expansion of the heated portions at the last forgings gave rise to interior ruptures in the already cold and finished parts. The metal was thus strained before use, and the wheels broke frequently in service. It was in consequence of these failures, doubtless, that the engineers of this country were led to employ exclusively wheels of cast iron. The railway companies are nevertheless greatly interested in the reduction of the weight of rolling stock, while preserving abundant, strength, and by the employment of wroughtiron wheels one may attain this double end if the defects of manufacture which we have just mentioned are avoided. This may be accomplished by making the wheels in such a manner that the different parts are welded at the same time, whereby the interior strains which so frequently give rise to ruptures in wheels successively forged are avoided. This result has been attained by what is known in France as the Arbel process, of which I will give you a short description if you will kindly give me a few minutes' attention. The process may be briefly summed up as follows: A pile of puddled bars of the general form of the wheel to be made is prepared,

By I. Lowthian Bell

THERE has been probably no improvement introduced into the manufacture of iron which created more surprise in the minds of practical smelters and of scientific men than Neilson's discovery of the hot blast. In 1829, Messrs. Dunlop & Co. consumed at the Clyde Works, near Glasgow, nearly 79 tons of coal to make a ton of pig iron, of which about 20 cwts. was employed under the boilers of the blowing engines, leaving nearly 7 tons for the consumption of the furnace itself. In the year 1833, by heating the air to 612' F. (322' C.), they redoccd the 79 tons to 3 tons by the mere burning of 8 cwts. of coal in the apparatus for raising the blast to this temperature. The statenlent just given is strictly true in a commercial sense, but when we come to consider the question as one of physical science, it is necessary to eliminate some of the conditions which conduced to so extraordinary a result. Anterior to Neilson's time the fuel employed in smelting iron was coke, and it was supposed at that period, erroneously, however, that coal in its raw state, when burned with cold air, was totsally unfit for the purpose in question. This mineral, as it was obtained from the Lanarkshire coal-field, contained about 35 per cent. of volatile matter, but the process of charring it was performed in so unskilful a manner that instead of receiving 88 cwts. of coke from 135 cwts. of coal, 60 cwts. only was the product of the operation. Again, the reduced colisumption of carbon in the furnace itself was accompanied by a corresponding diminution of blast, and this was followed by an economy of half a ton in engine coal. After making a proper allowance, however, for all these collateral circumstances, we are within the mark when we admit that in actual coke, which is really the form the fuel has to assume before it is burnt in the blast-furnace, not less than 30 cwts. was saved by heating the blast to 615° F. (322° C.). This unexpected economy, be it remembered, was obtained by the combustion of the 8 cwts. of coal, somewhat wastefully applied in the hot-air apparatus. Numerous have been the opirlions advanced by different authorities in the scientific world to account for the apparent anomaly, bat none,