WOOD-TIN, OR CORNISH TIN-ORE. 447 Externally it is glistening. Internally it is feebly glistening or glimmering, and the lustre is resinous, inclining to pearly. The fracture is delicate, straight, scopiform, and stel lular fibrous. The fragments are wedge-shaped and splintery. It usually occurs in large and coarse granular distinct concretions, which are intersected by curved and thin la mellar concretions, and the colour-delineation is in the direction of the latter. It is opaque. It is hard. The streak is shining, and yellowish-brown. It is brittle. It is easily frangible. It is uncommonly heavy. Specific gravity, 5.800, Brunnich. 6.450, Klaproth. Chemical Characters. Before the blowpipe, it becomes brownish-red, and de- crepitates, but is not fused, or reduced to the metallic state : when strongly heated in a charcoal crucible, it af fords about 73 per cent, of metallic tin. Constituent Parts. Oxide of Tin, - 91 Oxide of Iron, - 9 100 100 Vauquelin, N. Journ. Collet-Descotils, Ann. d. Chem. b. v. s. 231. d. Chem. t. liii. p. 268. Mexican. 95 a Gt agnostic