MINERALOGICAL CHEMISTRY. Mineralogical Chemistry. ii. 145 Errors in Silicate Analyses Composition of Alkali-free Aluminous Augites. G. TSCHERMAK (Centr. Mz’n. 191 6 L-9)- General remarks on the errors in the methods used in analysis personal errors and erxors due t o impurities of the material. Analyses made by-different authors on the same sample of material o r of a mineral from the same occurrence are compared and criti- cised. A further reply t o Boeke (A. 1911 ii 283) regarding the components assumed to enter into the composition of the alkali-free aluminous augites and a criticism of the analvses plotted in his diagrams many of which are rejected as untrustworthy. The author still maintains that the condition p=q+r holds in the formula pSi0,,qMg0,rCa0,sA1203. L. J. S. Identity of Kalk-Cancrinite and Meionite. L. H. BORGSTROM (Jahrh. 3Ji17. 1915 ii Ref. 310; from Ofz1cr.s. Fitiskn V e t . SOC Pb?h. 1915 57 ,4fd. A No. 6 l-3).-TJemberg’s (1876) analysis of kalk-cancrinite from Vesuvius agrees very closely with Borg- strorn’s carbonate-meionite CaCO,,SCaAl,Si,O (A. 1915 ii 836). The physical characters and paragenesis are also in agree- ment. L. J. s. F. JADIN and A. AXTRUC (Compt. re17d. 1916 162 196-197).-The authors have examined the waters from fifteen springs in the Alps for man- gailesel and find that they are on the whole poorer in manganese than the1 natural waters of the Central Plateau but richer than those of the Vosges mountains (compare A. 1914 ii 378 739). The presence of iron exerts a marked influence on the manganese content increasing i t considerably. Manganese in Some Springe in the Alps. W. G.