The Iron Age 1891-10-15: Vol 48

‘THE Defending New York Harbor. The Engineering Department of the United States Army is perfecting the last details of plans to complete the defenses of New York. These plans are for a great fort of modern mortar batteries at Plumb Island, to be constructed facing the ocean and defending the broad gateway of the harbor. The Plumb Island mortar batteries are to be arranged in two fortifications of earthworks standing side by side and fac- ing the ocean at a southwest angle. Each fort is to be 600 by 400 feet, according to Gen. Henry C. Abbott, president of the Board of Engineers, in whose office the plans have been prepared. The ramparts EN DAN RLU ft Y NEWYORK. Re THE of the forts are to be 35 feet above ebb tide, and the guns will rest on a body of cement raised 10 feet above low water. The interior of each fort is to be divided into four pits, each containing four of those terrible engines of destruction—12- inch howitzers, The guns will be fired out of a great well, as the earth walls of the fort will rise 25 feet above the level on which the cannons are operated. The mortars will thus be entirely invisible from the ocean. In the deep pits the guns will be perfectly protected tin the impact of the shot thrown by the enemy, as the mounds of earth forming the ramparts are to be of a thickness impenetrable by any known projectile. Between the pits will be storage magazines for powder, pro- tected by masonry and earth, and there are to be extensive magazines for high explo- sives located at some distance from the IRON AGE THURSDAY, OCTOBER 15, 1891. The 32 great guns for the two Plumb |The Ball Automatic Cut Off Engines. Island batteries are to be of the new pat- —_—— tern of 12-inch mortars known as howitz- Last week the Ball & Wood Co. of 15 ers, of which successful tests have recently | Cortlandt street, New York City, finished been made at Sandy Hook. They are | the first engine built at their new works at breech-loading, and constructed on the | Elizabethport, N. J. It is a simple en- built-up plan, steel lined, rifle bored | gine, similar to the one of which an en- and steel hooped. They are much longer | graving is here presented, having a cylin- than the old pattern of mortar, and | der diameter of 15 inches and a stroke of are capable of extreme accuracy in fir-|16 inches. It will be placed in the Tren- ing. The projectile for one of these|ton (N. J.) State House. monster cannons, which, dropped on the} The Ball Automatic Cut Off Engine was deck of the best armored ironclad in ex- | introduced in 1882 and atiracted attention istence, would pierce the entire ship, is of | chiefly because of 1ts novel system of regu- solid bulk of steel, 3 feet long, weighing | lation, in which the governor performed 625 pounds and costing $300. Eighty | the functions of a dynamometer, and this pounds of powder will drive this large | ‘‘ weighing of the load” became one of the projectile 8 miles. The gun will also' governing forces. This was the first en- BALL AUTOMATIC CUT OFF ENGINES. throw shells containing high explosives. | gine offered for sale under an ironclad con- By this means it can drop enough nitro- | tract to forfeit the engine if it could not be glycerine on a ship’s deck to scatter an/| made to fully hold to speed under full ironclad into 10,000 pieces. load. In 1886, F. HM. Ball, the inventor ee of this engine, discovered a method of ob- The census bulletin just issued giving | taining the desired result on an entirely the population of the State of New York | different theory, and as the new device by minor civil divisions shows in a strik- | presented fewer mechanical difficulties in ing way the tendency of large towns and | large engines and showed more correct cities to attract to themselves the rural | performarce under changes of boiler press- population. Under the census of 1880 the | ure, the weighing of the load device was population returned for the State was | entirely superseded by the later construc- 5,082,871; under the census of 1890 the | tion which, with the latest modifications, population returned was 5,997,853, an in- | is illustrated in Figs. 2and 3. The theory crease of 914,982, or 18 per cent., during | of this governor may be superficially de- the decade. During the same decade the | scribed as a peculiar balancing of the cen- inhabitants of cities and towns numbering | trifugal and centripetal forces, represented over 4000 people increased 38.71 per cent. | respectively by the swinging weights and In 1880 there were 60 cities and villages | the longsprings. The latter are supple- having a population of 4000 or more. | mente’ by the short spring having on its These places had an aggregate population | base the piston of a fluid dash pot. The batteries. The os magazines for! of 2,743,632, Under the present census | hub of the governor wheel is shown with each battery will hold 100 tons. In the rear the two forts will not be parquetted, | but will be left open. there are 84 cities and villages having a | the eccentric A bolted securely to its outer population of 4000 or more, with an aggre- | end, thus becoming practically a part of gate population of 3,805,577. the hub. This eccentric is provided with a eer ee 626 THE IRON AGE. October 15, 1891 an eccentric strap, B, made in halves and held in place on the eccentric by a flange on one side and the plate C bolted to the other side, as shown in the figure. The governor weights are connected by links D to studs in the side of eccentric strap, so that the strap and plate C are turned slightly around the eccentric by the radial movement of the weights. This plate C carries a crank pin, E, which, through the medium of a connecting rod, actuates the valve. The radial movement of the weights is thus made to turn the plate C around its center, which is eccen- tric to the shaft, and the crank pin E is thus moved through the arc of a circle whose center is the center of the plate, and the various points of cut off are thus obtained. The curved path of the crank pin is made to give almost a constant lead to the valve until a very early cut off is reached, when the lead rapidly disappears and prevents the engine from run- ning away. A much better indicator card, with earlier points of cut off, is thus produced that would be possible if the crank pin moved in a straight line when changing the point of cut off. It will be observed that only two moving surfaces are inter- posed between the shaft and the connect- ing rod which actuates the valve. Of these the crank pin is practically the only wearing surface, as it is the only one con- stantly in motion relatively to the surfaces with which it is in contact. The other, the eccentric strap, only moves on the eccentric when the weights change their position. The wear here, if appreciable, can be taken up in the usual manner for eccentric Fig. 2.—The Governor. straps, and ‘by removing the plate and scraping the side of eccentric strap any side motion can always be eliminated. There seems to be no reason why this mechanism should not outlast the engine and always run smoothly and quietly. In the use of a governer of this descrip- tion no restrictions are imposed in the ehoice of a valve. The valve here em- ployed, shown in Figs. 4 and 5, is made in two —_ having its faces opposite, and ‘| with telescopic sleeves connecting the two parts and allowing each face to be pressed =— its corresponding seat in the steam chest. Steam is admitted to the interior of the sleeves and thence through the ports into the cylinder, from which it is exhausted by the ends of the valve into the steam chest, and out through the ex- haust pipe at the bottom. The diameter of these sleeves determines the amount of pressure with which each part of the valve is held to its seat. A judicious choice se- cures just enough pressure for good con- tact, and not enough to make unnecessary friction and wear. These features are embodied in all the styles of engines built by the Ball & Wood Company, and are the outgrowth of long and intimate acquaintance with steam- engine construction. The company also build tandem, cross and vertical compound and triple-expansion engines. The gen- eral form of the latter is that of a double — The low-pressure cylinder is di- vided between two cylinders of moderate size, whose combined capacity represents the actual low-pressure cylinder. These divided cylinders are placed side by side next the frame, and tandem with one is the high-pressure and with the other the medium-pressure cylinder. F ———— EE The Cleveland Jron Trade Review says: ‘* Importations of cotton ties from England have entirely ceased. . . . In July, Fig. 3.—Details of Governor. 1890, we imported of ‘hoops or ties for baling purposes, barrel hoops and hoop or band iron or steel, flared, splayed or THE BALL AUTOMATIC CUT OFF ENGINES. punched,’ 9,215,082 pounds, valued at October 15, 1891 THE IRON AGE, 627 $134,499. During the seven months end-| bridge or breakage of a rail under the ing July 31, 1890, we imported 16,392,- 920 pounds, valued at $242,426. No im- ortations whatever have been made dur- ing the past seven months.” A Factor of Safety. Although the term ‘ Factor of Safety ” was originally adopted as a technical ex- pression by civil and architectural engi- neers, it has, by imperceptible degrees, become almost universally used in connec- tion with all branches of constructive en- gineering. It may be defined as a numeri- cal expression of the value or that per centage of the ultimate or breaking strain, Fig. 4.—The Valve. strain of a rapidly-moving passenger train ; the explosion of a boiler on a steamer out of reach of the shore? In such accidents as these, the destruction of possibly thou- sands of dollars worth of property, becomes a matter of relatively little importance as compared with the wholesale destruction of human life, which is the almost inevit- able consequence. And yet the daily papers tell us of the continual occurrence of just such accidents; and although from their very frequency they may fail to attract more than passing attention, unless of an unusually appalling character, the fact remains that the loss of even a single life entails upon some one a terrible load of responsibility. If the cause of the breakage leading to such results may be traced to the careless or ignorant use of the all-important factor of safety in origi- nally designing the construction, to whom does this responsibility belong if not to the engineer? Therefore the engineer be- comes another, or, in fact, the factor of safety, for to him is entrusted the problem, and of his skill the factor of safety is the creation. By none will the truth of this assertion be more promptly conceded than by the really competent and conscientious engi- neer. There are many instanceson record in which this feeling of responsibility for disaster caused by the failure of their work has driven such men to insanity or suicide, and, in not a few of these, subse- quent investigation has shown the cause Fig. 5.—The Valve and Steam Chest. THE BALL AUTOMATIC CUT OFF ENGINES. of the material, which may be safely sup- orted by the different elements or mem- ers entering into the construction of a building, bridge, machine or other struct- ure subjected to such strains, ‘“*factor of safety of 4” means 25 per cent. of the breaking strain; 5, 20 per cent.; 8, 124 per cent., &. Unquestionably one of the most impor- tant of the multifariousfunctions of the en- gineer is that of determining what this num- ber should be. It is essentially a matte- of judgment, dependent solely on the ex- perience and professional skill of the indi- vidual. Since the safety of life and prop- erty may depend upon its correctness, it becomes one of the gravest responsibilities possible to be voluntarily assumed. What, for instance, can be conceived more terrible in its effects than the col- lapse of a large dwelling, manufacturing or office building; the fall of a railway to have been distinctly due to other than constructive faults But there are engineers and so-called | engineers, The former, as a rule, men of Thus, a/more than average intellectual caliber, | whose naturally analytical habit of thought |leads them instinctively to consider the | relation between cause and effect. To such | —even though not originally educated for | the profession—the necessity for a general understanding of theoretical and applied ‘science becomes at once apparent as the | very basis of the technical information re- quired to enable them to follow this occu- pation. Such men, and only such, are fit material of which to make engineers. _And the greater their attainments, from study and practical experience, the more they are able to realize how exceedingly limited is their knowledge, as compared | with what there is still before them un- ‘ learned. In sharp contrast to the former class is the man who “‘ knows it all.” He also is engaged in engineering pursuits. But he sneers at science, says ‘‘ theory and prac- tice don’t always agree,” despises ‘‘ book engineers” and works by ‘rule of thumb ;” glorying in the thought (and in the very frequent expression of it) that ‘*he is a practical man and didn’t need to learn his business out of books.” This man, if designing a machine, building or what not, will consult his 2-foot rule, and with his two thumb nails moving back and forth on the graduations, will finally come to a decision and ‘‘ guess he’ll make that rod of 2-inch iron,” or ‘‘ that plate 4 inch thick ;” and it is so ordered. Heis totally and sometimes willfully oblivious to the fact that there are very simple rules and data which would enable him to calculate instead of guess what the size should be, provided his boasted ‘‘ practical” knowl- edge and experience of the physical proper- ties of the different forms as well as kinds of material is adequate to the occasion. He has then but to decide as to the proper factor of safety, and the strength of his construction becomes a known quantity— that is, the safe though not necessarily the maximum strength. But he has no use for formule, tables, nor calculations, nor for the factor of safety ; though why there should be any more necessity for accurate measurements in executing the work than in designing it, for using his foot rule and tape measure than his mathematical rules and data, would puzzle a logical mind to determine. Surely it cannot be any more important that the individual .members of the construction should be of dimensions which will admit of their being properly assembled, than that, as a whole, they should possess sufficient strength to render them safe to use for the purpose for which the construction was designed. If he wished to truss a 20-foot beam, to increase its capacity 25,000 pounds, it would seem to be quite as foolish to use a rod of proper length, 1 inch diameter, when 2 inch was required, as it would be to try to make one of proper diameter of 10 feet length answer the purpose for the given span. By the foregoing it is not by any means intended to convey the idea that only the highly educated are fit to be intrusted with work of thischaracter. On the con- trary, there are many among the ablest en- gineers inthe profession whose early ad- vantages were of the least, and yet they have attained to deservedly high reputa- tion by their skill through natural ability alone. But it may be safely asserted that they have been, without exception, men of the quality of intellect we have described, and that, before they be- came thus proficient, the necessary tech- nical education has been acquired against any and all obstacles. On the other hand, neither does it fol- low that, because a man may have a thorough technical and general scientific education, he will make a competent engineer. He has the formule at his fin- ger ends; knows the strength of material ; can work out problems involving the use of the higher mathematics, and in all respects, save one, possesses the requisite qualifications of an engineer. But he lacks the judgment necessary to enable him to correctly determine his factor of safety, without which all of his other knowledge is, not useless, but positively dangerous; it is like an arch with the keystone left out. Or, it may be that, while possessing the judgment, he is deficient in wisdom to follow it, and allows his desire to reduce cost, or some other motive, to tempt him into reducing his factor of safety below the number dictated by his judgment, and deliberately taking risks involving not only the safety of his professional reputa- tion, but that of the property and lives of others who were not consulted, nor had any voice as to whether or not they were Pern 628 THE IRON AGE, October 15, 1891 - willing to share the risk. In other words, he takes the risk at other people’s expense. We are not sure that this character of in- competency—for such it undoubtedly is— may not be considered as the most dan generous of all; and, that it exists to a serious extent, is beyond question. It is due to the active competition for the secur- ing of contracts, in which the generally satisfactory design, costing the least money, is the one usually sure of acceptance. This applies more particularly to architectural engineering, which of late years has be- come of the greatest importance as to magnitude of operations, owing to the im- mense number of large buildings continu- ally being erected; and in no class of work could the risk be more inexcusable, por the results more appalling in case of disaster. Of course it does not follow that be- cause the strength is insufficient to in- sure safety, the structure must inevitably give way. It was the ‘‘last straw that broke the camel’s back;” so in testing material up to its breaking strength, it bears to within an infinitessimal amount the strain which finally produces rupture. An overloaded column, wall or girder will not give way until the breaking strain is fully reached, but the elastic limit of the material once passed, the danger becomes imminent-—the least un- usual jar, vibration or increase of load in any manner being liable to produce rup- ture. Cases might be cited, ad infinitum, in illustration of this fact, where buildings, bridges and other structures have given way, when under no preceptible increase of the ordinary load, and upon investi gation as to causes of the accident, which naturally followed, it would be discovered that the ordinary load was close to the breaking limit. It not un- frequently happens that a building which was properly designed to bear the strains due to the purpose originally intended, may be wrecked by a criminal carelessness in overloading it many times beyond what was contemplated in its design. This, of course, is po fault of the engineer, al- though he may possibly have to bear the blame, at least until investigation shall have exonerated him, which is by no means a certainty, as some can testify to their sorrow. As to the different points to be considered in determining the factor of safety, their name is legion. The chemical and physical properties of ma- terials, the shape and probable condition of comparative soundness of the various mem- bers, uniformity or variability of con- ditions affecting the strains, &c., are some of the most important points, but there are others which, though quite as impor- tant, are not so apparent, and are more easily overlooked. It is the consideration of these multifarious features, overlook- ing none, and giving to each its correct relative as well as individual importance to enable him to arrive at its true value, which constitutes the engineer ‘‘a,” if not **the”™ factor of safety. I Under the beneficent rule of President Diaz Mexico continues to prosper. The revenues of the country have steadily in- creased during the‘last six years and for 1891 the total is estimated at $41,400,000. The debt now consists of $52,500,000 ex- ternal 6 per cent. bonds; $30,000,000 of 6 per cent. bonds issued for railway sub- sidies, and $24,000,000 internal bonds bearing 8 per cent. interest. The Govern- ment is also responsible for $6,500,000 bonds of the Tehuantepec Railroad and $2,500,000 6 per cent. silver bonds of the Monterey Railroad. On the total, interest of about $6,250,000 a year is required. With the prosperity indicated by the —_ of exports of home produce there as been a rapid increase in the income of the nation. BY W. H. Magnetic Ore Concentration.* HOFFMAN, M.E., CROTON NETIC IRON MINES, N. Y. MAG- The writer does not claim a right to dis- cuss this subject as a furnmaceman or user of iron ore in this new form. His efforts have been confined to mining, preparing and separating the magnetic ore from the gangue. Two years’ experience in ex- perimenting and another two years in pro- ducing concentrates on a commercial scale have led me to believe that the new trade of making concentrates must be well learned in all of its details. If thee have been any partial failures in this most useful branch of the iron business, the failures have been caused chiefly ,by inex- perience or lack of patience. Although I have, within the past five years, con- structed machinery for water jigging and wet magnetic separation, I shall only speak of the dry magnetic process here. Three years ago I was engaged by J. D. Cheever, the lessee of the Croton Magnetic Iron Mines at Brewster, N. Y., to adapt an old water jigging mill to the magnetic process. Theore to be treated is described by Messrs John Birkinbine and W. B. Kunhardt in a late report on the Croton Magnetic Iron Mines, as consisting of com- pact, moderately fine-grained magnetite in a gangue composed mainly of quartz and hornblend, besides feldspar, apatite and mica, and more or less pyrite and pyrrho- tite, and they say ‘‘ it is highly satisfactory that the grain of the ore permits a fair disintegration of its constituents by crush- ing it to pass a 12-mesh screen, inasmuch as a finer mineralization would increase the cost of concentration, as hereafter de- scribed.” Similar descriptions have been given Emerson McMillan, F. W. Gordon and Prof. N. 8. Shaler. By these gentlemen the average amount of metallic iron in the ore beds is stated to range from 87 to 42 per cent., the average sulphur from 1.7 to 2.2 and the phosphorus from 0.070 to 0.426. Practical work has shown the average amount of phosphorus to be 0.232. Since May 1, 1891, we have been roasting and concentrating this material to 68 per cent. in metallic iron, 0.44 in sulphur and 0.036 in phosphorus. Previous to this the concentrates ran about 66 per cent. in iron. Up to September 1, 1891, opening by drifting and prospecting with the diamond drill has exposed at least 8,000,000 tons of ore, ‘while it can be seen by a fair examin- ation of the property that there is not less than three times this amount of ore in these mines, and this estimate does not in- clude the mining rights owned personally by J. D. Cheever. Before the old water jigging mill was erected, some eight years ago, the product of these mines was sorted to remove the more sulphury ore, and was shipped di- rectly to furnaces making foundry irons. In order to meet the requirements of pur- chasers the mining company were obliged to reject, in cobbing, 2} tons to get 1 ton of shipping ore containing 51 per cent. of metallic iron and not more than 1 per cent. in sulphur. About 50,000 tons of this class of ore was shipped from these mines, The old dumps from this sorting are now being crushed and separated by the new process, Commercial success in concentrating any ore includes economical mining, prepara- tion and separation ; but in the Croton ore the presence of sulphur calls for very economical roasting as well as economy in all the other processes. The cheap roast- ing of the ore of the Croton Mine, which contains about 2 per cent. of sulphur, was * Read at the Glen Summit meeting of the American Institute of Mining Engineers. really one of the first problems encountered in reclaiming that property, and was really as important a factor as the concentration. A series of experiments was made to de- termine the best size for economical roast- ing, and as the end of three months a size that would pass through a 23 inch ring was adopted as giving the most rapid work for the quantity of fuelconsumed. Crude Lima oil is used for roasting. Through experi- ments conducted by our general foreman, T. Blass, we found the average consumption of fuel oil to be 3.75 gallons ; but by en- larging the combustion chambers we have reduced this amount to a little over 3.6 gallons per ton of raw ore. The cost of the oil is 2} cents per gallon, making a fuel cost of 84 cents per ton of raw ore. The labor of filling and discharging amounts to only 3 cents per ton, as this work is largely automatic. The average temperature is 1250° F. Davis-Colby roast- ers, remodeled to burn fuel oil, are used for a portion of this work, the remaining portion being done in a roaster of new type designed by the writer. The Davis-Colby roasters have been in operation nearly three years and have done excellent service. The ore is conveyed automatically from the roasters to the Sturtevant mills, where it is ground to 12-mesh size, all coarser material from the screens being returned to these mills by elevators. Barring the nu- merous experiments with various types of magnetic separators, the experiments in crushing have been the most elaborate. Nearly all the best-known methods of grinding ores have been tried at the Croton Mines during the past three years. Some of these machines have been tested for a year or more, but about 15 months ago we became thoroughly satisfied that the Stur- tevant mill was far superior to any other machine for grinding iron ores. The screen-block openings in the Stur- tevant mills are 4 inch wide, and the coareest material passing through them is less than ,', inch thick, while the finest material would be rejected by a 60-mesh screen. The ore enters the Sturtevant mills at a temperature of about 350°, be- ing cooled from about 1200° by a water bath on its way up the conveyor. Under these conditions the ore is quite friable, and we have no difficulty in grinding 22 tons per hour with the 20-inch mill and 16 tons in the same time with the 15-inch mill. One set of Sturtevant-mill bushings will grind from 4000 to 6000 tons of ore, according to the depth of the chill in the bushing, the cost of each set being $16. The screen blocks for this amount of ore cost $9. This is less than one-half the cost of renewal on any other machine formerly used at our mill. At 22 tons per hour the 20-inch mill requires 94 horse- power to drive it, but it will be remem- bered that the product is finished on these mills. The 15-inch mill requires 70 horse- power. The ground ore is elevated from the dis- charging nozzles of the Sturtevant mills to the several screens, covered with slotted steel plates made by the Harrington & King Perforating Company. The slots are ys X $ inch in some plates and , x 4 in others. The slotted plates are easily re- moved, and when the requirements are ex- acting as to phosphorus we - substitute plates of , mesh on two of our five screens. We have demonstrated by ex- haustive experiments that two sizes of screen plates, three sets coarse and two sets fine, will prepare the ore containing 0.426 in phosphorus (the greatest amount we have 1n the mine) for a separation hav- ing 0.036 with two passes on the magnetic separators. Ordinarily the phosphorus in the Croton ore runs from 0.1 to 0.3 per cent. When the phosphorus runs higher than six-tenths three sizes of screen plates should be used, delivering to three receiv- ing bins, and each size should be treated separately on the magnetic separators; and October 15, 1891 629 I am positive that this treatment will in- sure a Bessemer product running not over 0.05 in phosphorus, using nearly any of the New York State magnetites that are free from titanium. In some experiments we have used 18- mesh screens, and with ore prepared for this grade we were enabled to produce continuously, with two passes, concentrates showing 70 60 metallic iron, 0.018 phos- phorus and 0.220 sulphur. Of course the silica was extremely low. With the latest Hoffman separator, using 12-mesh screen, and making two passes, we have produced concentrates showing 70.93 metallic iron, 0.017 phosphorus and 0.231 sulphur; and by using 18.mesh screens we can depend THE IRON AGE. We always reply, as little as any other por- tion of the process. Seven cents per gross ton of concentrates is a liberal allowance, and this includes all repairs to separators. We shall reduce this to less than 6 cents soon. Repairs and supplies throughout our milling plant amount to 1,5; cents per ton of raw ore ground. Hence it will be readily seer that the feature of the prob- lem of magnetic separation is the initial mill grinding or granulating. The very cheapest process is absolutely necessary, as most of the ores to,be reclaimed will ana- lyze less than 40 per cent. metallic iron, and that means from 2 to 3 tons of ore to produce 1 ton of concentrates. Using Sturtevant mills and 22 per cent. ore, we MACHINE FOR THREADING BICYCLE SPOKES. on 71 per cent. concentrates with one pass | on this machine. ** Examinations for the purpose of detect- ing screen, shute and bin leaks must be made at least twice a week. The screens deliver their finished product to two bins | placed on the floor above the separating | department, each having a capacity of 80 | tons. Eight shutes deliver the ore to the | separators, ninein number, The separators | were designed and constructed by W. D. | Hoffman and T. Blass, at our mines. On' eight of the machines the ore is passed before the magnets twice to bring the loss | in tailings to 8 per cent. Our superin- | tendent, W. D. Hoffman, has lately de- signed two new separators, one of which is giving with one pass concentrates of 68 to 70 per cent., with a loss of only 6} per cent. of iron in the tailings. As patents are now pending, these machines cannot be described here. People frequently ask how much it costs to separate the iron ore from the gangue. can pay a small profit at our plant. Crushers and rolls require 28 per cent. ore to pay at the present price of concentrates. We contract our mining and initial crush- in gready for and delivered to roasters to Charles Vivian of Brewster, N. Y., at an average price of $1.38 per cubic yard. The ore weighs from 5500 to 6800 pounds per yard. Weare selling concentrates at present to six furnaces, which use from 35 to 53 per cent. of them in their regular mixture. The furnacemen tell us that their flux and fuel are reduced, but most of them decline to give the exact amount. We have yet to receive a complaint from any of our customers as to quality or fine- ness. An accurate, though condensed, state- ment of the cost of mining, crusbing, roasting, preparing, and separating one gross ton of 68 per cent. concentrates, from 2} tons of 88 per cent. ore, accord- ing to the present daily practice at the ings run, in iron, from 7 to 8 per cent. About one-third of the ore is taken from the old dumps. On the basis given below 580 tons is crushed every 20 hours, with a production of about 265 tons of concen- trates in the same time: Statement of Cost. Mining, crushing, and delivering to roast- ers 2 1-5 tons of raw ore, at 234 gross tons per yard...... A<sae Roasting, including top filling.......... 0.23 RE POON cccinciseake <eecauass 03 io and screening... ...... ... 22 Daily renewals, supplies and repairs of all machinery and roasters... .... ..... -. 5G Separating, including labor and power... 07 Delivery to Harlem Railroad switch, in- cluding railroad repairs ........ 04 Otfice and laboratory expemses.... .... . .U4 Insurance, interest and taxes on plant... .13 $1.95 During the last winter and spring a continuous run of five months was made of 20 hours each day, and the average cost of a gross ton of concentrates for the whole term was $2.10. Improvements have reduced this amount to the figures of $1.95, given above. Analyses are made at our laboratory daily of ore at mines, ore after leaving roasters, concentrates and tailings, by G. K. Volckening, Jr., our chemist. The following analyses cover an average two weeks’ shipments in July, August and September of the present year. All concentrates were from screens with slots jj; x 4 inch, and all samples were from carloads: July Aug. | Sept. 15 10 5. July 7. Metallic iron, dried at 212° F..... . | 68.55 | 68.080 68.259 70.090 Phosphorus, dried at Ziv° F..... 0.0865 0.0368 0.030) 0.045 Sulphur, dried at Siz? F .... 0.240 0.340 0.475 0170 Silica, dried at 212 Wuvada ‘eeageda as 3.500 3.610 2.951) 2.513 Rm — Machine for Threading Bicycle Spokes. The Capitol Mfg. Company of Chicago, Ill., have designed a new machine espe- cially intended for threading bicycle spokes. The threading head as used on this machine is similar to the Adame automatic, which we described in a pre- vious issue, with the exception that the dies can be universally adjusted, and one movement of a spanner, which is applied to a ring on the back part of the head, moves all four dies simultaneously. The dies can be adjusted to the very smallest fraction of an inch. The carriage is pro- vided with self-clamping and releasing vises, and all the operator has to do is to feed the machine. The thread is cut to its proper length, when the dies open and discharge the work automatically. The adjustment to cut the proper length is very simple, and the force pump sup- plies a continuous flow of oil. These ma- chines are also available for a number of other purposes, such as threading small rods, &c. The capacity of the machine is from the smallest to 4 wire. Some of the principal manufacturers of bicycles are now using these machines. I Although only seven years in existence, the salmon canning industry of Alaska has become more important than that of any other region. The increase in growth dur- ing the past few years has been phenomenal, especially in 1889, when the pack of 675, - 000 cases represented an increase of 377,- 000 cases over the previous year. How long the supply of salmon can keep up under this enormous drain cannot be pre- dicted, but it would seem that in any event Alaska is to be the great salmon Croton Mines, is given below. The tail-' region of the future. 630 WORLD'S FAIR NOTES. Progress on the Buildings. In every department of coastruction work at the grounds has been greatly ad- vanced the past week. Upon each of the buildings a larger number of men are now employed than hitherto, and this is true of all branches, grading, foundation-making, substructure, superstructure, iron work, staff-making, modeling and decoration, and landscape development. Summarized, the present state of the work upon the building is as follows : Manufactures and Liberal Arts.—Nearly one half of the foundation work is fin- ished and one-quarter of the area is now ready for flooring, in which about 350,000 feet of tumber has already been put in. Two gangs of men have been employed in floor laying and have followed up the foundation work as soon as it has been completed section by section. The work- ing force on the building has been doubled since last week. Fisheries and Aquaria.—The founda- tions are all in, sawmills running full ca- pacity cutting timber for superstructure. At present there is plenty of material to go on with. The construction track to the building has been increased and im- proved. Woman’s Building -—The roof structure is being commenced at the south end. Wood work of the entire edifice is well closed in, and the exterior covering of ‘*staff” is placed for the two loggias, or inner courts, of the west side of the north end of the building. Horticultural Building.—The founda- tion is completed, uprights are being placed for the superstructure, the piling for the dome is finished and the ironwork for the dome is arriving. Fine Art Gallery.—At the site of this building in the improved portion of the park, engineers and their assistants have begun work. The construction track is to be built at once and ground to be broken this week. Transportation Building. — The wood work the entire length of the building, approximately 1000 feet north and south, is nearly completed for the first story. Work on the second story is being advanced at the south end of the structure. Mines and Mining Building.—Three of the great iron trusses at the south end are now completed and all the supporting iron columns are in. The carpentry work is wellenough along to permit of exterior covering in some sections at an early date. Electricity Building.—Nearly all the main flooring is now finished and super- structure work will be begun early next week. Administration Building.—Foundation work is all in and iron work will be started as soon as the iron for building arrives. It is expected by the 15th. Agricultural Building —The founda- tions are practically completed and super- structure will be begun this week. Pier and Casino.—On the great pier all the principal construction work is finished and work will be begun on the *‘ mole ” or semi-circular connection of the Manufact- ures Building at once. Bids for Machinery Hall, Bids for Machinery Hall were opened on the 7th inst. by Chief Burnham. Owing to the peculiar form of the bids for iron work, the construction department is un- able to furnish the total of the lowest bids. The iron workers bid by the pound instead of by the job, and it will not be known until the building is finished how much that part of it is to cost. The low- est figures on the iron work were those of Binder & Seifert, 3.698 cents per pound. Exclusive of the iron work, the buildiog THE IRON AGE. will cost $645,910, the lowest bids being as follows: Carpentry work, Probst Con- struction Company, $358,217; painting and glazing, Reilly & Barker, $10,693; exterior covering, Staff Decorating Com- pany, $159,000; roofing, $118,000. J. A. McGonigle of Leavenworth, Kan., bid $318,800 for the carpentry work, painting and glazing, which is $50,110 below the sum of the next lowest bids for that work. The contracts will be let soon by the Grounds and Buildings Committee. Government Building Contracts, The Secretary of the Treasury awarded contracts for the Government building, at Chicago, to four different contractors, as follows: To James F. Reese, Chicago, wood work, painting and glazing; to Haugh, Ketcham & Co., Indianapolis, the entire iron work; to the Northwestern Construction Company of Chicago, gal- vanized iron and metal work; to George S. Lyon & Sons, Chicago, the plumbing. The aggregate cost of the contracts will be $316,757. By dividing up the contracts Architect Edbrooke makes a saving of $22,000. Contracts for the Art Palace, Contracts for the construction of the Art Palace were awarded on the 5th inst. by the Committee on Grounds and Buildings, as follows: Masonry, John Griffiths, $149,- 700; carpentry work, Steinmetz .& Eilen- berger, $68,793; galvanized iron work, J. C. McFarland, $42,855; structural iron work, A. Gottlieb, $51,400. Contracts for other portions of the work were not awarded. Lake Front Assembly Hall. Closely associated with the World’s Fair, but not forming a part of the group of buildings on the grounds, will be an important structure to be erected on the Lake front nearthe heart of the city. It will be known as the Lake Front Assembly Hall, and will be used during the Expo- sition for national and international as- semblies. After the exposition it will be used by the Chicago Art Institute as their permanent quarters. Part of the cost of erection is to be furnished by the exposition authorities and part will be raised by private subscription by the citizens of Chicago. The construction of the building was definitely decided upon last week. It will stand about where the old Interstate Exposition building is now located, which is to be removed within the next two or three months. Plans for the new building have been completed, and they provide for a very elaborate edifice, in the classic renais- sance. The building is to cost $600,000, Contracts will shortly be let. The Engineers’ Congress, E. L. Corthell, chairman of the General Committee of the World’s Congress Aux- iliary on Engineering Congresses, and chairman of the Executive Committee of General Committee of the Engineering So- cieties of the United States, has recently arrived home after an extended tour through European countries, in which he had occasion to come into personal com- munication with distinguished representa- tives of nearly all of the important engi- neering interests of the Continent. Inthe countries he visited he says nearly all the engineers he met signified their intention of coming to the congresses and the expo- sition. He attended the annual conven- tion of the Mechanical Engineering So- ciety of Germany, held at Dusseldorf. This society numbers about 6000 members, and the council decided to accept the in- vitation to take part in the congresses. Mr. Corthell was informed by the presi- dent of the Society of Civil Engineers and Architects of Germany, which also num- bers about 6000, that they had acted on the invitation and had gladly accepted it. October 15, 189) Letters have been received also from engi- neering societies in countries which he was not able to visit, expressing a great inter- est in the proposed congress, and giving assurance that their councils would act upon the matter immediately after their vacation. There has been also received a communication from the president of the Mexican Association of Engineers and Architects, with the information that the association is glad to accept the invitation, and that it will send delegates to the congress, Planning Their Exhibits. Two American industries of national importance are preparing to do something unusual at the Exposition. One is the National Association of Woolen Manu- facturers and the other is the American Pottery Association. Chief Allison has received from the secretary of the former association a resolution passed by its Executive Committee at a recent meeting, which provides for a special committee to confer with the Chief of the Department of Manufactures, and also resolves that the association shall make such a display of manufactured woolen goods as has never before been seen. The idea is to outrank the European representatives of the same industry. B. W. Blair, secre- tary of the Pottery Association, has applied for 225 blank appiications for space, and the secretary adds that the pottery makers of the United States intend to show European manufacturers that this country has made great strides in that particular branch. Brevities. Professor Ward, mineralogist, of Roch- ester, N. Y., called on Director-General Davis last week and offered to bring his entire collection of geological specimens to the fair. Professor Ward’s collection is considered one of the finest in the country. It represents the work of vears. At the Philadelphia centennial the col- lection was given a space of 120 x 130 feet. Frederick Bathurst of the Australian Mining Standard, writes to chief Handy that the last issue of the Standard con- tains a leader on the World’s Fair which he is sure will be appreciated. He adds: ‘*T may state that we have determined to make the Australian mineral exhibit one of the finest in the show, and I trust, there- fore, you will keep us well posted. Director George Schneider has received advices from Berlin to the effect that the associated chemical works of the German Empire had agreed to make a full and comprehensive exhibit at the Exposition in 1893. As is well known, the German Empire leads all the world in the matter of the chemical manufactures, and the ex- hibit thus determined upon cannot fail to be one of the most attractive and instruct- ive at the exposition. October 30 will be the World’s Fair day at the Texas State Fair at Dallas. That day every ove who owns stock in the Texas World’s Fair Association will be admitted free to the fair, and the association will try to have every visitor buy some of the stock. Texas is trying to raise a World’s Fair fund of $300,000, and has already made most encouraging progress. There will be not less than 25 restau- rants, as well as numerous cafés in the exposition buildings. It is the intention of the exposition authorities to protect visitors from exorbitant charges. —— EE A verdict of $7000 was obtained by the New York State authorities against the New York, New Haven and Hartford Rail- road Company, as penalties under the act forbidding the use of stoves in passenger coaches. October 15, 1891 THE IRON AGE 631 THE NEW MORTARS. Their Design and Manufacture. BY A. A. FULLER AND F, N, CONNET. Builders’ Iron Foundry of Providence, R. I., calls for 30 cast-iron mortar bodies, which are already completed; the second, with the Midvale Steel Company of Nice- town, Pa., calls for 30 sets of steel hoops }and mortar forgings, which are partially completed; the third, with the Builders’ | Iron Foundry, calls for the fiuishing: and ™ Through the courtesy of the Stevens In-| assembling of 30 12-inch breech-loading dicator of the Stevens Institute of Tech- mortars, which are now building. This nology of Hoboken, N. J , we are enabled | paper will treat only of the first and third contracts. to present the following very complete by the circulation of water through the core, according to the Rodman process, so that no excessive strains shall remain; radial, tangential and longitudinal test specimens from disks B and D, Fig. 1, cut from both muzzle and breech ends of the mortar, to have an elastic limit of about 11,000 pounds and a tensile strength be- tween 30,000 and 37,000 pounds per square inch, or nearly double the strength of ordinary cast iron; one-fifth of the en- tire casting to be cut off fora shrink or B Hoopes. SSSSSSS|SSSNSSSSSISSSSSSSSSSSSSSN LLLLLZ A ty: SOLS? LLL Fig. 2.—Arrangement of Hoops and Fig. 3.—Outline of Finished Mortar. description of the construction of the 12- AST IRON BooyZ24 Z | | ! ' no | i ! ‘ t x | ae — ee | 2 Ei, a) gantry | Ty ' ai ? | \ ' - . zi! | ’ | i * | = oe. i / ’ | | i lh. 0 | \ | N ° 2 | A -— ; A - 3!) S zit 4 ! | | | | | ' © < r rr? | | | | | | ‘ | o x Ne Ra | SQUARE INCH an? r | COMPRESSION FOR A&B Hoops. \, en ve a ee. oS os ! IPER INCH! IN DIAM. | fin ne Pin emtas did cate wn - o | ; | ; vz ° Ca) e ¢t a e a ° Fig. 1.—Outline of Cast-Iron Body. LL Compression Diegrams FABRICATION OF 12-INCH MORTARS. These mortars are of the French type, | inch rifled mortars now building for the | with breech-loading mechanism similar to Government. This subject is viewed | that introduced by De Bange, and, as their with unusual interest, owing to the fact | name implies, have cast-iron bodies with that guns of this kind are now at Sandy | two rows of steel hoops shrunk thereon. | Hook and will be tested during the next | These bodies have a 12-inch bore, are 129 | few months: inches long and 314 inches diameter, while | the diameter over hoops is 413% inches. The ‘‘ chase,” or forward conical part, The official designation of this type of | tapers down to 224 inches, as shown in gun is ‘12-inch breech-loading rifled | Fig. 1. mortar, cast-iron body, steel hooped, 14} The Specifications tons,” and the first lot of the same for our | in the first contract call for the casting to own Government includes the fulfillment | be made from charcoal pig and to be cast of three contracts. The first, with the | vertically, breech downward; to be cooled General Description, Fig. 4.—Diagram of Boring and Rifling Machine. sinking head, E, Fig. 1. From the disks are also to be cut two ‘‘initial stress ” rings, one near the bore and the other near the exterior. The diameter of each is observed previous to its be- ing parted off, and if initial com- pression be prescnt this diameter will increase after separation and a corres- ponding decrease will result from initial tension. The former is, of course, desired near the bore and the latter near the ex- terior. The metal is also tested for specific gravity and hardness; the latter is a com- parative test, and is made by forcing a 682 THE IRON AGE. Standard steel pyramid into the metal and | ply a reduction in length due to shrink- noting the depth to which it sinks under constant pressure. Most of the above tests are made on the Emery testing machine, at the Watertown Arsenal. Method of Casting. The body is cast vertically in a pit. The flask consists of six flanged cylinders, 57 inches inside diameter, clamped together. Each of the five upper sections of the mold is 3 feet higb, and is formed by ramming ‘‘dry sand” about a cylindrical pattern 33 inches diameter; the lower section, how- ever, is but 1 foot high, and contains a cast-iron pot placed in the center, around which the sand is rammed solid to a depth of 12 inches, thus forming a bottom for the mold; the rim of this pot protruding into the cavity of the mold fuses with the molten metal, seals the end of the hole made by the core and prevents the water from penetrating the sand when turned directly into the bore after the re- moval of the core. This core consists of a hollow fluted column about 8} inches outside diameter, wrapped with 4-inch manila rope, covered with about 3 inch of loam and faced with graphite. It is placed vertically in the center of the mold, and through its interior cold water is made to circulate. The metal is melted in what is known as an air furnace, which is a structure resembling the reverberatory furnace in its general characteristics, except that it has a tap hole at the lowest point of the hearth. The combustion takes place over grate bars, the hot gases passing over