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372 NATIVE METALS AND 1 2. 3. 4. o. 6. 9, Fig. l,the primary ; a rhombic dodecahedron. Fig. 2, the same, of which eight of the solid angles are replaced by as many triangular planes; which, in fig. 3, are increased greatly, forming the passage of the rhombic dodecahedron into the regular octahedron, fig. 4. Fig 5 is an octahedron, which has received an increase of crystalline laminae progressively di minishing in size, on opposite faces ; this crystal form3 the passage of the octahedron into the tetrahedron, fig. 6, in which the triangular planes of fig. S have received a still further increase of laminne. Fig. 7, a regular octahedron, of which the six solid angles are replaced by quadrangular planes, which are increased and complete in fig. 8, the cube. Fig. 9, a crystal in the general form of the rhombic dodecahedron (fig. 1), but mo dified in part with the small equilateral triangular planes of fig. 2, and of which the edges are alternately replaced by isosceles triangular planes inclining on the solid angles. Blende (the black-jack of English miners) is a mineral of very frequent occurrence, being met with in beds and veins accom* panying most of the ores of silver and lead. It is found not only crystallized as above, and in macles, but massive, fibrous, and botryoidal. Ihe dark-coloured crystalline varieties are prin* cipally from Derbyshire, Cumberland, and Cornwall, though many splendid specimens are also brought from Transylvania, Hungary, and the Ilartz. A transparent bright-yellow variety accompanies bournonite and fahlerz at Kapnik; a still more brilliant one of an oil-green colour occurs at Schemnitz; while Pon P' or P" 120* 00' H. P; P', or P" on u 133 00 P on t, or cf 144 44 — a on c, e\ or c". 23 15 — e. on t' ore" 109 28 — if one" over a 70 31 — ^■ong-overa 129 31 —