346 SILICATES. P Phosphoric acid . . 0-12 Silica 37-oo Boracic acid . . . 7-68 Alumina 33-09 Bed oxide of iron . . 9-33 Protoxide of iron . . e-19 Protox. of manganese — Magnesia .... 2-68 Lime 0-50 Soda 1-39 Potash 0-66 In analysis t the red oxide manganese. 1 r S t U — 0*12 trace trace — 36-74 36-61 36-82 37-24 38-43 8-00 7-62 8'70 7-62 8-06 34-40 32-92 35-50 33-97 34-25 761 8-13 6-67 10-77 9-98 8-60 9-51 7'68 1-95 l - 44 — o-ii — — — 1'76 0-78 1-56 3-65 3-84 0-86 0-72 0-81 0-62 0’44 1-02 1-36 0-98 1-93 1-36 0-47 0-68 0-09 0-82 0-30 of iron contains some oxide of Analyses of dark violet, blue, green tourmaline generally con taining lithia and iron along with manganese, and in which the proportions of oxygen in the bases b, » and in the acids are nearly as the numbers 1, 9, 12, v blue, from Sarapulsk near Mursinsk, w violet, from Elba, x green, from Elba, y green, from Paris in the state of Maine, z green, from tho Brazils, n green, from Chesterfield in Massachusetts:— G Pluorine . . . Phosphoric acid . Silica .... Boracic acid . . Alumina . . . Bed oxide of iron Oxide of manganese Protoxide of iron Magnesia . . . Lime .... Soda .... Lithia .... Potash .... V W X 3162 2-942 3-112 1-75 2-00 2-35 0-06 — — 38-30 36'71 38-19 6-32 7-11 7-68 36-17 36-00 39-16 6-36 7-14 3 14 3-71 (Ma 5'62 4'26 3-84 — — 0-53 2-30 l'OO 0-27 0-80 0-84 2-37 2-04 2-40 — — 0-74 0-33 0’38 0-34 y Z a 3-089 3-107 3-108 2'00 2-09 2-10 — traces —■ 38-47 38-66 40-26 7-69 7-29 7-79 40-93 38-40 38-00 3-08 6-13 2 - 61 1-66 073) 0-90 — 2'00 3'80 1-21 0'73 0-80 0-88 1-14 0-81 2-36 2-37 2-09 1-47 1-20 0-20 0-36 0-37 0'04 Analyses of red tourmaline containing lithia but no iron, in which the proportions of the oxygen in the bases a, ft and in the acids are nearly as tho numbers 1, 12, 16, /3 from Elba, ,y from Paris in Maine, 5 from Schaitansk in the Ural, t from Bozena in Moravia, probably decomposed:—
