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Mr. Williams stated that peat employed in connexion with coal makes a most improved coke. If one-fourth of Lancashire peat be added to three-fourths of coal, a coke which the iron-masters pronounce to be the best for the manufacture of iron is produced, whereas coke from the coal simply cannot be used for this purpose.

Extracts from Smeaton's MS. Papers, communicated by John Farey, M. Inst. C. E.

Iron with

Mr. Smeaton, in a letter dated 25 Nov. 1778, remarks, that he had Smelting seen at Furness Fells in Lancashire a Blast Furnace for smelting Peat. iron with peat. This peat iron, made by Mr. Wilkinson, possessed extremely small grain, and the metallic atoms being very closely combined; and was found to answer well when mixed with other iron for making slit mill rollers.

Peat.

Mr. Farey also communicated some extracts from the papers of Use of Mr. Mushet respecting the manufacture of iron with peat; the quality of the fuel, and the nature of the iron produced therefrom.

Feb. 12, 1839.

The PRESIDENT in the Chair.

The following were ballotted for and elected:-Robert Hawthorn, Nicholas Harvey, William West, as Members; J. R. M'Clean, as a Graduate; E. W. Brayley, as an Associate; and General Sir John F. Burgoyne, R.E., as an Honorary Member.

Cement.

Mr. Simpson presented some pieces of iron hooping which had Iron and been imbedded for 26 years in cement, and which were blue as when first put in; the iron hooping had been placed round stone pipes at their junction, and covered with cement. From these specimens it is evident that a coating of cement is a perfect preventive of corrosion.

G

Peat and
Resin Fuel

"On the Properties and Composition of the Peat and Resin Fuel." By C. Wye Williams, A. Inst. C. E.

The nature of the fuel being of great importance in the manufacture of iron and arts generally, it is interesting to inquire into the value of peat for these purposes. Peat may also be used for railroad engines, and with peculiar advantage, being free from many of the impurities of gas cokes: it may also be used in combination with resin, or other bituminous substances, as a fuel for long voyages. The bogs of Ireland were, nearly 30 years ago, designated by a Mr. Griffiths as mines above ground; who remarked, also, that the iron founders in Dublin might probably, ere long, be supplied with turf-charcoal, which is superior to every other for their purpose. The attention of the author was directed to the use of peat for the steamers on the Shannon, where coal is necessarily dear, and peat was at first used only for economy; the impediments to its use, from its bulk and dampness, being great. The property of holding and absorbing moisture is also a great impediment to its use, particularly in wet seasons, the only remedy for which is great care during the process of drying and in its subsequent preparation, any care being amply repaid by the diminished consumption. The evils of its bulk and low specific gravity may be obviated by compressing it when dry; when compressed perfectly dry, and kept free from moisture, it will preserve its bulk. From some observations of Tredgold, respecting the earthy impurities and odour of peat when burnt, it is obvious that he experimented on peats from the lower strata; but the author, in opposition to several eminent philosophers, maintains that turf coke may be made more effective than wood charcoal. The author, in his first experiments, came to the same conclusions for using the lower though impurer strata, simply because they were the denser, and rejecting the lighter kinds. The lower strata sometimes contains peat of a tolerable purity, but generally the upper and lighter portions are superior in the purity of the carbon, the intensity and quality of its heat, to those portions which have acquired density by time and natural pressure. When the density is acquired by artificial pressure, we have a substance superior to any other for all purposes of metallurgy.

The difficulty in the conversion of turf into coke has hitherto lain in depriving it of its volatile substances, so as to make a pure carbon, and in avoiding waste by partial combustion. This is effected by an union of the distillatory with the stifling process; the volatile substances are expelled in the oven, and when sufficiently charred the stifling process is adopted. Turf for the forge must

have a greater density than that acquired by this process. This is effected by pulverising or bruising it, so as to destroy the fibrous character, and bring the component parts into closer and more permanent contact. By the union of these processes, any density may be given to the fuel which will combine the purity of vegetable charcoal with the density of mineral coke. The specific gravities of the turf hard pressed (water being 1000) is 1160-of the coke from the hard pressed 1040. Thus, the hard pressed turf is denser than the densest wood, and the turf coke double the density of charcoal and equal to coal coke.

The test adopted by the author, after Berthier, of the calorific power, or relative power of absorbing oxygen, is the quantity of metallic lead reduced from its state of oxide by given weights of the several fuels. Pure carbon gives 340 grains, wood charcoal 307, turf coke 277, best coal coke 277.

Thus we have a measure of the relative quantities of heat; but intensity of heat is often of more consequence than quantity, and intensity depends on the density of the fuel. Berthier remarks, that the superiority of coke to wood charcoal is owing to its density. In the above comparison, no account is taken of the impurities of the fuels; consequently, turf coke, being free of sulphur, has great advantages. The author finds that iron worked with turf coke is sooner brought to a welding heat, works softer, and comparatively free from scales.

The author then describes the resin fuel as an artificial coal produced by imitating the process of nature, in the best combinations peculiar to coal. Natural pit coal consists of bituminous, carbonaceous, and various foreign ingredients, of which sulphur is in abundance, and very injurious. The resin fuel consists of resin, the purest available bitumen, and turf coke, the purest vegetable carbon. Thus, the greatest heating power exists in the smallest bulk, and the excess of bitumen and deficiency of carbon, as in cannel coal, or excess of carbon and deficiency of bitumen, as in anthracite, may be avoided. Resin, notwithstanding its price, is used in steam navigation, but very disadvantageously, in combination with cinders, as it melts and passes off in a state of vapour, not entering readily into combustion with the oxygen of the atmosphere. But in the resin fuel, in consequence of the extraordinary attraction which subsists between carbon and oxygen, the resin has its full combustible and calorific effect. In the furnaces of boilers, a solid cinder is requisite, which may be produced by adding some of the inferior bitumen, as pitch and tar. The fuel is manufactured by adding turf coke, in a state of powder, to the bitumen in a melting state, and in such quan

tities as to saturate each other. The average price of the fuel is 40s. per ton. Its use was fully tested in the voyages of the Royal William, in which 20 cwt. of coal, with 2 cwt. of the fuel, did the work of 26 cwt. of coal. The suddenness of the action and the great increase of heat for a small increase in its consumption, render it of great value in cases of emergency. The author concludes by expressing his conviction, after ten years' experience, that the turf bogs of Ireland may be rendered available for many important uses in

the arts.

Coke Fuel.

Coke

Mr. Lowe called the attention of the meeting to the valuable mass of facts which had recently been recorded. It was on these that the chemist must build his theory of combustion, and not strain his theory to the facts. We cannot doubt the facts of Apsley Pellatt and Josiah Parkes; men of undoubted acuteness and close observation, and not to be deceived. Marcus Bull again, under totally dissimilar circumstances, viz. the raising by 10° the temperature of a chamber, exquisitely insulated, and observing how long it can be maintained at this temperature by a given weight of different fuels; and accurately noting the loss sustained by the wood in the process of coking, came to similar results. With respect to shell bark hiccory, whose specific gravity is the same as that of water, and loses three-fourths of its weight by coking, Marcus Bull finds that equal heat is produced by 6 lbs. of hiccory charcoal, and by 15 lbs. of dry wood. So that we may say a given weight of the dry wood produces just double the effect it would if made into charcoal.

There is clearly something in coal and wood whose action is not beneficial, as the residual coke does, according to these three men, produce the same effect as the original weight of fuel. The resumè of these experiments shews, that to deprive bituminous coal of certain portions of oxygen, carbon, and hydrogen, is not to depreciate its heating powers; according to Mr. Williams' experiments we find, that to add a bituminous substance to a pure coke or carbon, is greatly to increase its heating power. It is fearful to think how often we are self-deceived; men do so lean to their preconceived notions and to their wishes. He could almost always get a yea or a nay indifferently from his workmen. The person who would not be deceived, and rightly study the laws of combustion, must himself turn stoker.

To say that no heating powers are given off by the process of Ovens. coking, would be just as absurd as to give credence to the statements

that every thing can be done by coke ovens. This is proved by the statements of Mr. Cubitt, in the first volume of the Transactions, who applied, at Ipswich, the waste heat of coke ovens to heating gas retorts, and the same is still done at Reading. Whether the coke it produces is equally good with that made in the usual routine, remains to be proved. But to say that the 15 cwt. of coke, produced from a ton of coal, is equal in heating powers to the original ton, is to say that there were no heating powers from the 9 or 10,000 cubic feet of gas produced, or the 10 gallons of tar. The contrary is selfevident, and the whole mystery is cleared up by supposing that in the ordinary routine of furnaces most of the bituminous and gaseous products pass up the chimney, asking for heat rather than giving off.

any

Mr. Horne particularly called attention to the fact mentioned by Mr. Williams of the fibre being broken down. Most experiments on compression had failed from this having been neglected.

Mr. John Taylor had for seven years worked coke ovens for the purpose of distilling wood. Several tons of coal were coked every week, and three large retorts, 6 feet by 8, were worked. The heat of one coke oven was effective for four of these retorts, and the coke sold for the cost of the coal. Here there was clearly an available heat. There is great difference in the mode in which fuel is employed; coke is peculiarly valuable in a locomotive, because of the draught; the bituminous coal of North Wales is bad for steam engines, as compared with the coal of South Wales. Of this he knew a striking instance. Soon after Messrs. Grose had erected, in Cornwall, their famous 80 million engine, one in every respect similar was erected in North Wales. A duty of 70 or 80 millions was expected. It never rose above 45°. They tried some Swansea coal-the duty immediately reached 70 millions. The bituminous effect of the North Wales coal is lost-it distils off; and this is shewn by the fact, that when fresh coal is thrown into the furnaces in North Wales a cloud of smoke issues from the chimney, but in Cornwall no smoke is visible.

They once had occasion to try wood, and the hot blast which succeeds so well with coke will not do with wood, and in all the metallurge process the wood must be coked. Turf charcoal has, to his knowledge, been in use at Dartmoor for forty years. For welding, and all fine works, it is the best. Peat has been most extensively used in the North for smelting lead ore; now a small quantity of coal is mixed with it. He had used peat in a reverberatory furnace for calcining lead ore, and for this purpose dry peat, with a small

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