TURBITH MINERAL

is the yellow sub sulphate of mercury. TURF ( Peat , Scotch; Tourbe , Fr.; Torf , Germ.); consists of vegetable matter, chiefly of the mo family, in a state of partial decomposition by the action of water. Cut, during summer, into brick-shaped pieces, and dried, it is extensively used as fuel by the peasantry in every region where it abounds. The dense black turf, which forms the lower stratum of a peat-mo , is much contaminated with iron, sulphur, sand, ., while the lighter turf of the upper strata, though nearly pure vegetable matter, is too bulky for transportation, and too porous for factory fuel. These defects have been happily removed by Mr. Williams, managing director of the Dublin Steam Navigation Company, who has recently obtained a patent for a method of converting the lightest and purest beds of peat-mo , or bog, into the four following products: 1. A brown combustible solid, denser than oak; 2. A charcoal, twice as compact as that of hard wood; 3. A factitious coal; and 4. A factitious coke; each of which po e es very valuable properties. Mr. D’Ernst, artificer of fire-works to Vauxhall, has proved, by the severe test of coloured fires, that the turf charcoal of Mr. Williams is 20 per cent. more combustible than that of oak. Mr. Oldham, engineer of the Bank of England, has applied it in softening his steel plates and dies, with remarkable succe . But one of the most important results of Mr. Williams’s invention is, that with 10 cwts. of pitcoal, and 2 1 ⁄ 2 cwts. of his factitious coal, the same steam power is now obtained, in navigating the Company’s ships, as with 17 1 ⁄ 2 cwts. of pitcoal alone; thereby saving 30 per cent. in the stowage of fuel. What a prospect is thus opened up of turning to admirable account the unprofitable bogs of Ireland; and of producing, from their inexhaustible stores, a superior fuel for every purpose of arts and engineering. The turf is treated as follows:—Immediately after being dug, it is triturated under revolving edge-wheels, faced with iron plates perforated all over their surface, and is forced by the pre ure through these apertures, till it becomes a species of pap, which is freed from the greater part of its moisture by squeezing in a hydraulic pre between layers of cay a cloth, then dried, and coked in suitable ovens.—(See Charcoal , and Pitcoal, coking of .) Mr. Williams makes his factitious coal by incorporating with pitch or rosin, melted in a cauldron, as much of the above charcoal, ground to powder, as will form a doughy ma , which is moulded into bricks in its hot and plastic state. From the experiments of M. Le Sage, detailed in the 5th volume of “The Repertory of Arts,” charred ordinary turf seems to be capable of producing a far more intense heat than common charcoal. It has been found preferable to all other fuel for case-hardening iron, tempering steel, forging horseshoes, and welding gun-barrels. Since turf is partially carbonized in its native state, when it is condensed by the hydraulic pre , and fully charred, it must evidently afford a charcoal very superior in calorific power to the porous substance generated from wood by fire.