DIGGING AND DRYING PEAT. 53 in Northumberland as well as Yorkshire considerable quantities of peat firing are expended. It is scarcely possible to pass-in the Summer season especially, through those parts of Ireland which are remote from the capital and the larger towns, without witnessing somewhere or other, the operations of the turf-diggers. The turf-spade, in shape is not unlike that used by gardeners in general; but is lighter and narrower. With this implement, the workman first cuts away, in a sort of large cubical sods, the superior turfy stratum of the bog: as this is comparatively loose and light, it is presently dried and ready for use. On digging lower, the substance of the peat becomes more moist and compact, and appears more like rotten wood than the roots of moss; it has, however, a sufficient degree of fibrous connexion to admit of its being readily raised in masses somewhat resembling large bricks. These quadrangular clods, which the digger cuts out and throws up with great dexterity, are heaped in small stacks to dry; after which, they are either used on the spot, or carted away by purchasers, according to circumstances -to preserve them through the Winter, the piles are sometimes thatched. On sinking still lower in the bog, the matter becomes less solid, loses its coherency, and assumes the consistency of black sludge; this is laded out with a scoop, similar to that used by brickmakers for wetting their clay, and is thrown upon a smooth floor or bottom, where, from exposure to the air, it stiffens and consolidates; it is then cut and cross-cut with the spade into cubic masses which, on becoming dry, are found to burn with great freedom, in consequence of the bituminous saturation, to which the matter of them seems to have been subjected. The accumulations of peat differ considerably in area, depth, and quality. On the banks of the Shannon, one of the moss tracts is stated to be about fifty miles in length, by two or three miles in breadth. In mountainous situations the depth of the bed is seldom above three feet-rarely so much: in bogs and low grounds, into which alluvial peat is "drifted," it is sometimes found forty feet thick-though fully one-half of this volume is water.* The quality of peat varies according to the different situations where it is formed; as those places differ in drainage; in the nature of the vegetables they produce; and in the kind and quantity of alluvium deposited among the dead vegetable matter. The conditions of purity, compactness and weight, are required in those kinds which have been sometimes estimated as equal to inferior coals. Dr. Mac Cullocht considers peat as presenting five obvious varieties, depending upon situation, viz.,mountain peat, marsh peat, lake peat, forest peat, and marine peat: he likewise gives lists of such bog and other plants as he conceives enter most largely into the composition of each kind. As a fuel, however, Mr. Tredgoldt appears to consider it sufficient to divide peat into two kinds only-the first, that which is compact and heavy, of a brownish black colour, and with scarcely any vestiges of its vegetable origin * Inundations of fluid peat have occasionally taken place to a considerable extent. In most of the instances recorded, the bogs have become so saturated with moisture, that, lying aslope above some subjacent level, they have slid or flowed down. A notable instance of this sort was the irruption of a part of the Solway Moss, which at the time [1772] consisted of 1300 acres very deep and tender: a part of this mass, on being deluged with rain, flowed from its ancient bed, and covered 300 acres of the adjoining land, to a depth of 30 feet.-Phil. Trans. vol. xiii. p. 305. Abridgment. + Edin. Phil. Journal. Vol. ii. p. 40. Tredgold on Warm, and Vent. Buildings, p. 44. VARIETIES, AND CHARRING. 55 remaining; this is the best kind :-the second is light and spongy, of a brown colour, and seems to be a mass of dead plants and roots which have undergone little change; it inflames readily and is quickly consumed. It must be remarked, however, that so highly imflammable are some even of the denser kinds, that the characteristic distinctions of bituminised wood are considered insufficient to explain the circumstance—and hence, the Ince peat of Lancashire is believed to be penetrated by petroleum derived from some bituminous spring.. According to the authority above named, the weight of a cubic foot of peat, varies from 44lbs. to 70lbs.; the denser variety affording about 40 per cent. of charcoal. Sir H. Davy has stated that in general, one hundred parts of dry peat contain from 60 to 99 parts of matter destructible by fire, and the residuum consists of earths, usually of the same kinds as the substratum, as clay, marl, lime, &c. The practice of charring turf obtained at an early period, especially in Germany where it was much used: it is said to have been employed in this state at the Freyberg smelting houses about the year 1560, though the undertaking, Beckmann assures us, was not attended with success. In some parts of Bohemia, Silesia, Upper Saxony and other places, as we learn from the same authority, it is common to subject the turf used in working metals, to a certain degree of combustion in kilns or furnaces; after undergoing this process, it is considered that it kindles sooner, burns with less air, and forms a more moderate and uniform fire. Attempts to substitute peat treated as above, for charcoal in some of the smelting establishments of this country, were not unknown during the earlier part of the seventeenth century. And at this day, a description of peat called in some parts of Devonshire "Blackwood," is, when cut, dried and charred, used by the smiths in tempering edge-tools. "Turf," says an Irish writer, Dr. King,* “is accounted a tolerably sweet fire; and having very impolitically destroyed our wood, and not as yet found stone coal, except in a few places, we could hardly live without some bogs; when the turf is charred, it serves to work iron, and even to make it in a bloomery or ironwork; turf charred, I reckon the sweetest and wholesomest fire that can be; fitter for a chamber, and for consumptive people, than either wood, stone coal, or charcoal." Notwithstanding this truly Irish eulogy of the national bog fuel, one of the strongest objections to the use of peat for domestic fires is the disagreeable odour it emits while burning. But in this, as in many other instances, we are reminded of the adage de gustibus nil disputandum; for Mr. Loudon, in his interesting Encyclopædia of Cottage, Farm, and Villa Architecture, mentions that, in most parts of the Highlands of Scotland, peat fuel is so abundant, and the people so attached to peat smoke, that when new houses, built with stone and lime, with chimneys to carry off the smoke, were introduced on the Marquis of Stafford's estates, many of the farmers refused to live in them; and it took years, before others could be reconciled to the clean and cold appearance which they alleged was produced by the want of smoke. * Phil. Trans. Vol. xv. Abridgment. 1685. CHAPTER IV. NATURAL HISTORY OF COAL. Nature and origin of Coal-Different opinions which have been entertained on that subject-Hypothetical queries answered-Inferences and illustrations of the vegetable origin of Coal-Chemical investigations of Mr. Hatchett-Three conditions of Fossil Fuel; submerged forests, lignites or bituminized wood, and true Coal-Description of the Bovey Coal formation-Supposed state of the atmosphere at the period when the Coal Vegetables flourished-Remarks on the prodigious supply of materials-Forests and drift wood-Have the vegetable matters forming the Coal strata been floated from a distance, or did they originally grow in situations near to those places where, in their changed condition, they are now found? Causes which may have operated in effecting the bituminization of the Coal plants—Opinions of Mr. Penn and others-Supposed peaty origin of Coal-Anthracite. OF the formations or suites of strata already briefly described towards the close of Chapter II., that containing the carbonaceous deposits is the most interesting its age and composition, involve problems |