360 SILICATES. a b C d e / Soda 13-36 16-83 16-44 14-93 16-91 20-46 Potash 7-13 6'60 4-94 4'72 4’52 — Lime 0-90 0-84 1-77 1’82 2-01 — Ox. of iron and man. 1-50 1-07 0-65 0-39 0-44 — Water 1-39 1-39 0-21 0'21 0-21 0-62 Analyses of coloured varieties (elseolite) q from Friedrikswiim (green), h from Eriedrikswam (brown' , i, k from Brevig (brown), Z, m from Miask (white), all by Scheerer, n by Bromeis:— "rom Miask (white) 3 h i k Z m n Silica . . . 45'3l 45-55 44-59 44-48 44-30 44-07 42-33 Alumina . . 32'63 32-00 32-14 32-03 33-25 33-12 34-39 Soda . . . 15’95 16-09 16-67 16-76 16-02 15-70 16-26 Potash . . . 5'45 5-02 5-10 5'24 6-85 5-69 6’95 Lime . . . 0’33 trace 0-28 0-24 0-32 0-26 0-47 Bed ox. iron . 0'45 1-41 0-86 1-30 0-82 0-67 trace Magnesia . . — — — — 0-07 trace 0’45 Water . . . O'flO 0-78 2-05 2-06 — 0-90 0-92 According to Bromeis and Scheerer, nepheline and elseolite contain traces of hydrochloric and sulphuric acids. In attached and imbedded crystals and massive. The white varieties (nepheline) are found on Monte Somma in matter ejected from Vesuvius, in a basaltic rock at Capo di Bove near Eome, in dolerite on the Katzenbuekel near Heidel berg, Meiges in Hessia, the Lobau mountain in Saxony, Miask. The coloured varieties (elseolite) in syenite near Laurvig and Brevig in Norway, near Miask in the Ural. 203. LEUCITE.—Leucite; Phillips. Trapezoidaler Amphigen-Spath; Mohs. Ilai dinger. Cubic. d on cleavage, n 211. Amphigene; Hauy. Leucit; llausmann, Fia. 377. dd’ nd nn / nn 00“ o 64 44 48 11 33 33 Cleavage, d, very imperfect, extending a very small distance below the surface. Eracture conchoidal... uneven. Semi-trans parent... translucent. Lustre vitreous ; the surface of fracture