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selves of the hot blast to introduce inferior and cheaper materials, and the result has been, that the quantity of coldblast iron, which by official returns is stated to exceed 770,000 tons in the year 1840,—and therefore at that time exceeded one-half of the whole annual make of the country,was in 1860 estimated (for there were no official returns) at about 150,000 tons, not much more than one-thirtieth of the whole make of that year.
It is not contended that the cold blast exclusively produces tough iron of high quality. The precise effect of the hot blast is much disputed among practical and scientific men, nor has it ever been satisfactorily ascertained whether, if the materials were precisely the same, the quality of the produce would be deteriorated by the lot blast. But the hot blast may be applied to any materials, from the very best to the very worst; the cold blast can be applied only to the best, and hence its produce bears a higher price than the best of the hot blast in the market, either because practical men think it really better, or because they are willing to pay more for an article which is guaranteed by its very name. The introduction of the hot blast has conferred an infinite benefit on the iron trade and on the country, but it has brought with it a redundant supply of an inferior article, and an unlimited power (and with the power the temptation) to practise false economy and to commit fraud. Hence have arisen two results which have generally been confounded, and which it is desirable to keep distinct. The one is, that there has taken place a notable deterioration in the manufacture. There is annually.produced a larger quantity of inferior iron than can be used for reservoirs, cisterns, and the multifarious purposes to which inferior iron is legitimately applicable, and at periods of unusual demand the inducement to produce quantity at the expense of quality acts with irresistible force. At the first establishment of railways, for instancethe time is now remote, and truth has oozed out — in the hurry and eagerness of the moment, the manufacturers were often urged by the surveyors to send “any rubbish,' provided it were made smooth and looked nice, and were delivered quickly. But at all times the cheap and inferior quality is forced into use by competition. Competition acts feebly in an early state of society, and in a different direction from that which it takes in a more advanced stage of civilisation. Its first aim is to produce something more costly and more choice, to win the patronage of the few; its
* Vide a pamphlet entitled • What is good Iron, and How to get it.' London : 1862. From which we have borrowed some of these curious facts.
next is to bring the luxuries of the few within the reach of the many; cheapness becomes its chief object, and often ends in being its sole object. We long cherished the belief that no iron is so bad that it could not be turned to some account; but
practical men affirm too confidently to admit of dispute, that iron is produced which is good for nothing but to sell, and woe betide those who fall in with it. Dî meliora piis, erroremque hostibus
· ‘illum.' It is remarkable how little the danger of a deterioration in the manufacture seems to have attracted the attention of professional writers on the subject. Mr. Scrivener, in the second edition of his history of the iron trade, published in 1854, announces with exultation that in that year the annual make had reached the amount of 2,700,000 tons (since so much exceeded); but the only drawback he apprehends is that the resources of the country should not long suffice for so large a production, and no fear of possible falling off in the quality seems to cross his mind.
The second result to which we have alluded is not less important. Amid the vast increase of different qualities of iron, to which it would be an abuse of language to apply the word bad, as they are excellent for the different purposes to which they are specially applicable, there is a very insufficient supply of the best tough iron, the kind of iron which is needed when the material is to be subjected to much manipulation, and is required to maintain its toughness to the last — the kind which, above all others, is required for the manufacture of armourplates.
The reader is aware that wrought iron is brought to its perfection by repeated working; but some kinds of iron reach their perfection after very few heatings, and all kinds after a certain number of heatings begin to decline in quality till at last they are utterly worthless. Mr. Clay tells us that in six workings iron of ordinary quality attained its highest degree of strength, improving at each stage, but after each of six subsequent workings it successively sustained an inferior test. (Metals and their Alloys, p. 317.) Superior iron would endure further
. mauipulation ; but it is only the very best which will bear the repeated heating and reheating to which the armour-plate is subjected, without losing its fibrous texture and its toughness. It is for this reason, moreover, that iron in the half-manufactured state, of which we have spoken, the “puddled bar,' is recommended as the proper material for an armour-plate. In a more advanced state, iron, however good in quality, has not enough vitality left in it to endure the manipulation to which it must be subjected.
In the use of the new ironstones great skill has been attained in devising mixtures, so as to correct the opposite defects of the several ingredients; but the correction is insufficient to produce a material that will answer purposes for which a high degree of toughness is required. For these purposes the only iron which is entirely suitable is that produced from the clay ironstones. We observe, with entire coincidence of opinion, that Mr. Fairbairn, in his lecture, assumes that none other can be thought of for the plating of ships. He confines his tests to these alone. When the value of the argillaceous ores for the production of tough iron,-- which was the leading maxim of the old iron trade, -is thoroughly and practically recognised, the improvement which has been made of late years will be as solid as it is striking; but unhappily this recognition is opposed with all the zeal which interest combined with local attachments and prejudices can inspire. Most manufacturers are very much in the hands of their managers; the manager has a strong interest in keeping down cost: on this his credit depends, and no way of keeping down cost is so convenient to himself as economy in the quality of the materials. Moreover, he probably has come from one of the new iron districts, and he brings with him the practice and the maxims of the district where he has received his training. No stronger confirmation of this can be given than Mr. Fairbairn's remark, that “white iron is almost always preferred for forge purposes. Now, in the same page Mr. Fairbairn tells us that 'the pigs in which carbon most predominates that is to say, the grey
pigs,) have, as a rule, been least contaminated with other impurities during the process of smelting, and are in many • respects preferable for the manufacture of wrought iron,' and the grey forge iron bears a higher price in the market, because it is acknowledged to be the most valuable. But so many managers have been reared in districts where the materials will produce none but lighter-coloured iron for forge purposes, that, by habit, they have learned to prefer the inferior article even without reference to its greater cheapness.
Nothing would be more interesting than a series of wellconducted experiments to test the properties and qualities of the principal - makes' of iron in the kingdom. But the work is one of great labour and expense, and would require a complete practical knowledge of the trade and the manufacture, which it would be difficult to find in combination with the requisite mechanical and scientific skill. Many insulated sets of experiments of great interest have been made. But the difference of their dates, and the want of this local and practical know
ledge in the experimenters, much impair their utility as guides. The tabular statement of the strength of different kinds of iron which Mr. Fairbairn gives (Table VII.) in his work on the application of iron to building purposes, is interesting chiefly as a matter of history. Since his trials were made nineteen of the works he mentions have been abandoned (not all of them permanently it is to be hoped), three of them have been pulled down, and one has been converted into a railway station. Of those which are quoted as producing cold-blast iron, ten are now using the hot-blast. Moreover, as far as we can judge, all the kinds of iron are not of the same denomination; that is to say, some are more suitable for forge, and some for foundry purposes, and therefore are not such as can be fairly compared with each other. But the descriptions of the iron are somewhat vaguely given, and we presume that what puzzles us can be explained by the diversity of nomenclature prevailing at different times and in different districts. In the year 1858 the iron masters were invited by an advertisement of the Ordnance Office to send in specimens of their make, to be subjected to a series of chemical and mechanical tests. Unquestionably to comply would have been patriotic and politic too on the part of the iron masters, especially those who produced the best iron; but the invitation was clogged with conditions which excited jealousy, and manufacturers whose iron enjoyed the highest repute were precisely those who had the least reason for wishing to enter into the proposed competition. Out of more than two hundred iron masters only eighteen sent in specimens, and of this small number only four are among those whose iron Mr. Fairbairn selected as the subjects of his own experiments.* The result is that though the report of these experiments published by the Ordnance Office contains much important information, it is but a very slight contribution towards the great desideratum, a full account of the properties of the different kinds of pig iron which form the raw material of the iron manufacture of the United Kingdom.
To take a general survey of the products of the British manufacture, and to compare them with those of foreign lands, we turn to the International Exhibition. The most profitable object of such a comparison would be to note the
* A private manufacturer would have ordered 'trial lots' of iron from the firms who in his opinion manufactured the best iron of the description he wanted. The more nearly Government can assimilate its course to that of a private firm, the more efficient its operations will be.
many points on which we may derive some useful hints from the industry and skill of strangers; but at present we desire only to form some idea of our relative position with respect to the means of national defence. And, considered with reference to this object, the survey is highly satisfactory. The improvement in the iron department since the last Exhibition of 1851 is very remarkable. The dimensions of some of the specimens exhibited are such as we believe cannot be equalled by any other country; but we are not entitled to draw this conclusion from the absence of any foreign specimens of equal size, as the transport of such large masses would be both difficult and costly. Great progress has been made in the art of casting. The large pipes of 4ft. diameter, for the conveyance of the waters of Loch Katrine to Glasgow, would have gladdened the heart of James Watt, when in his early days he toiled so hard, and for long in vain, to get the cylinders for his steam engines cast 'straight. And how great is the progress since those days when the benefit of Sir Hugh Myddleton's New River was almost neutralised by the foulness of the perishable wooden pipes by which its water was distributed ! The forging of the large masses of iron for the engines of the war vessels is very superior. Nothing can be better than the work of the cross heads' and 'connecting rods for the frigates, and the 'crank shaft' of the 'Achilles' is a masterpiece in respect of size and soundness.
In large rolled sections the superiority rests with our manufacturers. Neither in quality nor in size does any other country exhibit iron so well adapted for the reconstruction of the navy. The great difficulty is to lay down mills for what are called in the trade “extra sizes.' But the extra sizes of one period are the ordinary sizes of another; and the roll-turners of twenty, ten, or even five years ago, would be astonished at the specifications which are of every-day occurrence now; and when even larger sizes are needed, we do not doubt that mills will be found to execute the orders. Much of the improvement which has taken place must be ascribed to the energy of the new districts, where the iron was suited to fewer purposes than that of the old districts, and greater exertions were needed to bring it into general use. It is ever thus. It is the poorer soils and the less
. genial climates that call out the most active energies of the farmer. At this time we are assured that there is not a mill in Staffordshire that can roll an armour-plate, and scarcely more than one hammer to forge one.
This should be amended. A visit to the Exhibition makes it clear that we can produce steel of the very finest quality from native materials, and for