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OXIDES, EAHTIIS, AND ACIDS. FIG. 287 FIG. 285. FIG. 286. := * Forms and combinations, a, o, d, ao, od, ds, aod, odm, odep, odems, aoyz. The faces d usually striated parallel to their inter sections with o ; p smooth but curved ; the faces of the other forms usually smooth and even. Twins. Twin-face o. Cleav- age. a, o distinct...traces. Fracture conchoidal...uneven. Opaque. Lustre metallic, sometimes imperfect. Iron-black. Streak black. Brittle, n = 5-5... 6-5. G = 4-96... 5 20. Fusible before the blowpipe with very great difficulty. In the inner flame imparts a bottle-green colour to borax. In powder is perfectly soluble in warm hydrochloric acid. FeJPe, red oxide of iron 68'97, protoxide of iron 35'03, or iron 72-41, oxygen 27'59. Analyses of magnetite a from Norra in Sweden by Berzelius, b crystallized from Dannemora in Sweden, c massive from Grelli- vara in Lapland, d crystallized from Berggieshiibel in Saxony, e crystallized from the Tyrol, all by Karsten, f crystallized by Fuchs:— a b C d e / 11 Red oxide of iron 69 69-95 69-40 67-95 67-66 68‘40 1 Protoxide of iron 31 29-63 28-25 29-92 28-66 30*88 : Titanic iron oxide — 0-25 3-31 — - Earthy matter — 0-15 — 1-86 — — In attached and imbedded crystals, and disseminated, in chlorite slate, serpentine, granite, syenite, basalt, &c.; usually massive in beds with augite, amphibole, garnet, quartz, calcite, pyrite, hematite, in gneiss, mica slate, chlorite slate, horn blende slate, clay slate, greenstone, marble, very seldom in veins; sometimes in rounded grains in alluvium in Stream works with gold, platinum and various gems. Is found in enormous masses in Norway near Arendal and other places in Sweden, Dannemora in Upland, the island of Uto, near Norberg in Westmanland, Philipstad in Wermeland, on the Q-rengcsberg in Dalarne, on the Taberg mountains in Smaland, in Lapland in the mountains Kurunavara and Luos-