MINERALOQICAL CHEMISTRY. Mineralogical Chemistry. ii. 117 Hausmannite in the Batesville District Arkansas. H. D. MISER and J. G. FAIRCHILD ( J . TT7ashington Acad. Sci. 1920 10 1-8).-The abundant manganese ores of this district consist of the oxides psilomelane hausmannite braunite manganite pyrolusite and wad the first two which occur intimately intergrown being the commonest. They occur as irregular masses weighing from less than a pound to 22 tons embedded in clay limestone shale sandstone etc. The hausmannite however occurs as a replacement material only in the limestone and as a residual material in clay derived from limestone. Analysis I is of a sample from the W. T. Gray mine near Pfeiffer and I1 from Club House mine near Cushman; they correspond with hausmannite (Mn,O,) with 13% and 31% admixed psilomelane respectively.MnO. 0. Fe,O,. AlI.03. SiO,. CaO. I. ...... 91.38 7.78 Nil. Nil. Nil. Trace 11. ...... 90.40 8-87 0*48* 0.10 Trace - MgO. BaO. H,O. Total. Sp. gr. 1. ...... Trace 0-26 0.62 100-04 4.836 II. ...... Trace Nil. 1.03 100.88 4-778 * Fe,O trace. The ' braunite' desoribed by Penrose in 1891 is shown to be such a mixture of hausmannite and psilomelane. Braunite is readily distinguished by the fact that it yields considerable gelatinous silica. L. J. S.ii. 118 ABSTRACTS OF CHEMICAL PAPERS. Analyses of Dolomites. ALBERT R.OTHROCK and J . B. SHunrAKm (Chem. News 1920 120 29-31).-The following analyses of dolo- mite rocks and dolomitic limestones from various localities show considerable variations from typical dolomite CaMg(CO,) which ccntains CaCO 54*35% MgCO 45.65%.I white compact crystal- line from Ossining New York. 11 dark grey massive from Cum- berland. 111 light-coloured massive from Cerro Gordo Inyo Co. California. IV grey compact with conchoidal fracture from Frankenstein Silesia ; this approaches magnesite. V white corn- pact and crystalline resembling marble from near Keeler Cali- fornia. VI greyish-white crumbly and saccharoidal from the Binnenthal Switzerland. VII hard compact from Gerolstein Rhine. VIII light colour with pearly lustre from Costa da Val Tyrol ; 2CaC03,MgC0,,FeC0,. IX greyish-white compact from New Almadin California. X light grey granular and porous from Raible Carinthia. XI. grey large crystals from Brewster’s New York. XII a outer layer of pale pink crystals b inner portion of dark grey crystals.XIII grey from ‘The Dolomites,’ Tyrol. XIV from the Brenner Pass. CaCO,. MgCO,. Fe,O,. Al,03. SiO,. Total. Sp. gr. I. ...... 51-97 37.40 0.20 Trace 10.61 100.18 2-93 11. ...... 57.59 24.98 16-05 0-87 0.56 100.05 2.88 III. ...... 87-88 11.85 0.09 - 0.06 99.88 2.57 V. ...... 66.08 1.15 0.06 - 32-57 99.86 2.7 VII. ...... 52.93 44.33 0.80 0.22 1-23 99-51 2-82 IX. ...... 53-28 45-18 8.57 - 0.4 100.11 ? 2.8 XII~. ...... 56-63 41.37 1-18 0.63 0.23 io0.04 - XII~. ...... 57.18 36-83 0.89 1-16 3-96 100.02 - XIII. ...... 94.21 4.15 0.56 0.57 0.48 99.97 2-73 IV. ...... 27.04 67.91 3.71 0.73 0.13 99.52 2.9 VI. ...... 49-00 40.23 0.48 - 10-84 100.55 2.85 VIII. ...... 49-59 24.50 2.36 - 0.12 100.01* 3.01 X. .,.... 54.64 45-18 Trace 0.28 0.23 100.33 2-7 XI. ...... 59.98 36.83 2.44 - 0.33 99.58 2.9 -+ XIV. ...... 96.25 2-98 0.50 0.35 100.08 - * Including FeC0,,23.44. L. J. S.