untaba nokia download

Clarke's figures have the molecular formula: Na 2 O 0.173 \ / K 2 O 0.090 A1O 045 SiO 2 3.0 aO 0.264 I F * o 8 O 'o49 "I Ti 2 ' 022 MgO 0.327 P 2 5 0.005 FeO 0.146 J ( The melting point of such a mixture would be about 1,200 C. As the temperature of the earth, according to the figure adopted by the British Association, increases 1 C. for every 117ft. in depth, it follows that we have at least 25 miles of solid earth beneath us. Owing, however, to the pressure of the superincumbent strata, the melting point of the rocks is probably raised appreciably, but the depth given indicates a minimum limit. The specific gravity of the primary rocks of the earth's crust is 2.6, while that of the whole earth is 5.5, the difference being due either to pressure or to the sinking of the heavier elements towards the centre. The primary, Cm AM 1C CHEMISTRY. or igneous, rocks are classified according to their silica content, the following table giving the most important, with the essential minerals of which they are composed. PRIMARY ROCKS. Group Silica Vitreous Hemi-cry-