820

APPENDIX.

dissolve and enter into fusion, so as to form an entire and com-pact mass, I should decidedly call bituminous.

5. There yet remains another class of iron making coals, viz.,the anthracite, which, properly speaking, do not form a coke atall, in the usual acceptation of the term. Water and hydrogen areexpelled in small quantites during the distillation, and a slightdiminution of bulk is sustained, but no new arrangement, as isthe case in the usual transition of coal into coke; the fractureremains the same, and equally conchoidal as before, without thecellular structure peculiar to coke; a structure, to ensure whichin the most limited degree, would require the coal in coking toevolve at least 10 per cent, of carboniferous flame. When coalbecomes anthracitous, or is passing into the state of anthracite, itis found sometimes divided into laminae of flame coal and anthra-cite ; the former in coking assuming the cellular arrangement,but the latter remaining unchanged as to structure, though agood deal discoloured by the discharge of the gas from the flamepart of the coal.

To understand correctly the definitions and descriptions whichmay be made use of in the course of these details, it is necessaryto state, that the general structure of the red ash coal is cubical,but of the white ash various—cubical, rhomboidal, and oblong.In some of the veins near Merthyr , a conical arrangement is fre-quently observed, with an approach to a regular crystallization.When the cubical, rhomboidal, and conical structures prevail,accompanied with a minimum proportion of bituminous matter,the affinity of aggregation is frequently so much reduced as t&present fractures of a regular granular structure in the form ofcubes or imperfect rhombs, and held together by a slight adhe-sive force.

SECTION I.

COALS OF THE SOUTH WALES COAL BASIN.

Analyses of seven varieties of the Mynyddyswyn vein of coal;so called from its having been worked in the parish of that name.Thickness from 3g to 4 feet, and yielding from 3000 to 4000 tonsof marketable coal per acre; and of which the produce of 150acres at least per annum, is dug and carried to Newport for sale.