Journal of the Chemical Society Abstracts
An a 1 y t i ca 1 C h e m i s t r y. Witt's Filtering Apparatus. By A. BORNTRAGER (Ber., 19, 1690). Microscopic Analysis of Minerals. By T. H. BEHRENS (Rec. Trav. Chim., 5,1-33) .--This paper contains a description of methods used for the analysis of small fragments of minerals with the aid of the microscope, based on the detection of the various constituents by conversion into various compounds, the crystallographic f orrns o r appearance of which are well known. The mineral is dissolved in
... is dissolved in hydrofluoric acid, o r an acidified solution of ammonium fluoride, and the fluorides converted into sulphates under such conditions that the fluosilicates and fluoaluminates only remain unaltered. Then in the concentrated solution obtained, the calcium is detected in the form of sulphate, the potassium as the platinochloridc, sodium as a double sulphate of cerium and sodium, lithium as sulphate after separation of the calcium sulphate, and barium and strontium also as sulphates. The double phosphate serves to indicate the presence oE magnesium, and an alcoholic solution of alizarin, $hat of aluminium. For the detection of chlorine, mercurous is preferable to silver chloride ; for fluorine, the best reagent is sodium chloride, the fluoride being previously converted into a silicofluoride. Test analyses are given, which were made with 0.0002 gram of tourmaline, of an apophyllite, a boracite, and other minerals.