470 NTOBATES. Metallic acids . . . . Yttria Protox. iron. . . . . Protox. mangan. . . . Lime Ox. uranium . . . . Magnesia Protox. cer. ox. lanthan. Loss ign a b 0 d e 56-38 56-00 55-91 61-33 57-81 9-15 11-04 8'36 19-74 18-30 15-43 15-90 15-94 8-06 13-61 0 - 92 1’02 1-88 1-00 2-08 0'31 0'50 14-16 16'70 16'77 U 6-64 1-87 0-80 0-75 0-75 T1 1-50 5'90 2-27 — — 1-66 The metallic acids in analyses a, b, c are a mixture of niobic and scheelic acids. The acid in analyses d, e is supposed by Hermann to be that of a new metal, ilmenium. According to H. Rose, it is a mixture of niobic and scheelic acids, which possesses all the properties of the substance called ilmenic acid. Is found in imbedded flattened grains, with aeschynite, im bedded in felspar in the Ilmen mountains near Miask. Accord ing to H. and G-. Rose, the mineral called yttroilmenite by Hermann is samarskite. 305. AESCHYNITE.—Aeschynite ; Beudant. Dystomes Melan-Glanz, Mohs. Aeschynit; Hausmann, Haidinger. Prismatic. 011,010=36°3l'; 101,001 =33° 40'‘4; 110,100=63° 39''5. a loo, b 010 cleavage, 0 001, 0 111. ca 90° o' oa 68‘ 3 18' me 90 0 oc 56 28 va 36 47 oo' 43 24 VC 53 13 oo" 96 56 vv' 106 26 o'o" 112 52 mm 52 41 om 33 34 rr 89 26 Combinations. camv, camo , amrvo. FIG. 464. iiui-j miu eaun otner; ine oiner faces uneven. Cleavage, b, traces. Fracture imperfect con- choidal...uneven. Faintly translucent on the edges...opaque. Lustre imperfect metallic; the surfaces of fracture resinous, bright. Iron-black... brown; hyacinth-red by transmitted light. Streak yellowish-brown. Brittle. H = 5'5. g = 5'1...6'3. , . n matrass yields a little water and traces of hydrofluoric acid. Before the blowpipe intumesces and becomes yellow or