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plates of 25 or 30 tons, which were afterwards consolidated under the crushing blows of the 80 ton hammer. At St. Chamond, near St. Etienne, are to be found two ladles, each capable of holding more than 25 tons of fluid steel; and there the needful power of resistance is sought to be conferred on armour plating by annealing the pieces in a cistern containing 100 tons of oil.

Perhaps a still more impressive illustration of the vast power of the appliances employed in the manufacture of iron is furnished in forging the coils for ordnance purposes, as first suggested and first practised by Sir William Armstrong. It is, indeed, a marvellous sight to behold a mass of metal, sometimes weighing as much as 50 tons, drawn from a cavern heated to dazzling brilliancy, and then to watch the ponderous steam hammer effect a weld, many yards in length, so perfectly as to be able to resist the tremendous strain which modern artillery has to endure.

Thus it may be said that, about the commencement of the present century, 20 or 30 tons of metal per week, as dribbled from our blast furnaces, was handed over to the Lancashire fire and its accompanying hammer of puny dimensions. By their united action something like a ton of wrought iron bars was obtained every 24 hours; which bars could only be sold at prices that forbade their use except in very limited quantities. From this primitive state of the process we pass to the blast furnace, driven with heated air, and furnishing 20 puddling furnaces with a weekly supply of something like 250 tons of metal apiece. In these 20 furnaces the laborious exertions of 80 men were required to agitate the molten iron, so as to expose a succession of fresh surfaces to that chemical action, by which it was purged from the foreign substances acquired during the smelting of the ore. The heat of the puddling furnace, being far below that required to fuse the iron, when separated from its associated carbon and other bodies, all the workman could do was to soften his product, and then, by hard manual labour, cause it to stick piece by piece together in the furnace itself.

In the puddling furnace something like an hour and a half was needed for dealing with 4 to 5 cwts. of pig; and two good men did well if they laid 22 cwts. of puddled bars on the bank, for a day's work. In

place of this laborious operation, 7 or 8 tons of metal are now brought direct in one charge from the blast furnace, to the converting vessel; and the same air which burns off the impurities, by its passage through the iron, dispenses with the use of any other motive power, than that furnished by the blowing engine. In 15 or 20 minutes the crude metal is malleable iron; and the change is wrought with such rapidity, that the heat evolved by the combustion of the impurities is intense enough to maintain the contents of the converter in a perfectly fluid condition.

Chemically, as stated above, the product is malleable iron; mechanically, it possesses certain points of dissimilarity. Upon our ability to modify these latter will depend the realization of those prophecies, which predict the complete supersession of iron by what is generally, but often somewhat improperly, denominated steel.

Leaving the past and looking to the future history of this national industry, the question uppermost in the minds of our iron masters is, undoubtedly, the application of ordinary British pig iron to the manufacture of ingot metal or steel. The Transactions of the Iron and Steel Institute are replete with proofs of the attention which this problem has received for some years past at the hands of its members and others.

By some it may be considered premature to declare that the elimination of the phosphorus, which constitutes the barrier to the use of pig iron obtained from our clay ironstones, bids fair to become a generally accepted process in our steel works. The laws, however, which govern the removal of this hurtful ingredient are sufficiently well understood, and enough has actually been done to justify the assertion that it is a subject which has progressed far beyond the region of experimental research. In illustration of the complete success which has attended the application of the Basic process, in the removal of phosphorus during the process of conversion by the Bessemer system, the average composition of 47 rails, made of the best hematite iron from the works of three makers, is contrasted with that of 20 rails made at the Eston works, from pig containing probably 1.75 per cent. of phosphorus. Both lots were taken indiscriminately as received by the North Eastern Railway, and analysed in the laboratory of that Company.

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With such results before us as those recorded in the above figures, it is clear that the only question which requires consideration in connection with the removal of phosphorus from iron is the cost at which it can be accomplished. In other words, can the cheap pig of Cleveland, when burthened with the expense attending the Basic treatment, compete with the dearer metal of Lancashire and Cumberland, which latter can be converted into steel by a somewhat simpler manipulation? This is the question to which those interested in metallurgical science in Great Britain still await a definite answer.

The effect, in an economic point of view, produced by the various improvements briefly reviewed in the present Section, is little short of marvellous. During the 40 years already alluded to as ending in 1826, pig iron was rarely quoted below £5, while the average over the entire period may be taken at £7 per ton. Recently we have seen the same article sold at 32s., and steel rails of the highest quality have been obtained for a considerably less sum than the lowest average price of pig iron during any year of the 40 years above referred to. This great change in the cost of production is, to some extent, to be ascribed to the discoveries of such ores as the Black Band, and those found in Cleveland and analogous districts. The chief source of economy is, however, unquestionably due to the improvements introduced into the manufacture itself.

SECTION III.

ON THE DIRECT PROCESSES FOR MAKING MALLEABLE IRON.

MALLEABLE iron and steel are obtained, as has been described, by the circuitous method of first making pig iron, and then removing the foreign matter which the metal has taken up in the furnace from the materials used in smelting. Any process, therefore, having for its object the production of malleable iron from the ore at one operation, is distinguished by the use of the word "Direct."

No serious attempt has been made to revive in this country the obsolete and almost forgotten Catalan furnace-much less its more humble predecessor, the low hearth of Asia and of Africa. It is desirable nevertheless to consider briefly the conditions of this primitive mode of procedure, in order that we may more correctly appreciate the ground upon which it is now sought to resuscitate a process, now so long abandoned in almost every iron making community in the world.

I have had no opportunity of inspecting such a furnace as that previously referred to, and described to me by Colonel Grant; but, according to Dr. Percy,1 in the operation as pursued in Asia, the structure costs under ten shillings, and the furnacemen are satisfied with three half-pence per diem. Even at this miserable rate of wages, the cost of labour on the raw mass or ball is probably much more than that at which the same ore could be converted into a steel rail ready for use, by men earning on an average 4s. or 5s. per day. In producing the bloom, six times its weight of charcoal is used, and half the iron contained in the ore is lost. In reheating the crude lump for forging into a bar, one half its weight is wasted, and again there is a considerable expenditure of charcoal. We are probably within the mark in accepting

1 Work on Iron and Steel.

as a fact, that ten times as much fuel and three times as much ore are required, for every unit of metal produced, as is consumed in the blast furnace and Bessemer process together.

Some Catalan furnaces, which I had an opportunity of examining in North Carolina, were near 3 feet from back to front and 2 feet from side to side, by 18 inches or 2 feet in depth. They were blown by a trombe-a very simple form of apparatus, in which the current of air is produced by water falling through a square upright box of wood, the blast being conveyed to the hearth through stems of trees bored for the purpose. Into the furnace are thrown charcoal and ore, the latter in small fragments. The hot embers, and the masonry heated by the previous charge, quickly cause combustion to pervade the mass, when the blast is turned on.

In this direct mode of dealing with the ore, as in the blast furnace proper, there are two distinct stages through which the mineral has to pass: viz., first, the expulsion of the oxygen with which the iron is associated, and secondly, the raising of the reduced metal to a welding heat in the bloomary, or to the fusing point in the blast furnace. Again, so far as economy of combustible is concerned, it is essential that the intensely heated gases, generated at the tuyeres, should communicate as much of their heat as possible to the materials, on their way downwards in the furnace. Failing this, the loss by the gases escaping into the atmosphere at a high temperature is exceedingly great.

It will be most suitable to defer considering, with the proper degree of minuteness, the questions raised by the conditions just enumerated, until we are describing the action of the blast furnace. It will be convenient, however, to mention at the present moment that, as the office of reduction is to withdraw oxygen from the ore, it is of importance that the gases near the tuyeres should be as free from this gas as possible, otherwise there would be a risk of reoxidizing the metal. This is the case in the blast furnace, because reduction is performed in the upper part of the furnace during the gradual and slow passage of the ore downwards; but in the Catalan or any similar furnace, much of the mineral is deoxidized at or near the tuyeres. Hence arises the necessity of burning additional quantities of carbon, to give sufficient reducing energy to the gases at this point. Even with this precaution,

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