428 ZINC. Physical Character. It becomes phosphorescent by friction ; and, according to Bergmann, as powerfully under water as in the air. Chemical Characters. It decrepitates before the blowpipe, becomes grey, but is infusible either alone or with borax. Constituent Parts. • Yellow Blende from Scharfenberg. Zinc, - . 64 Sulphur, - - 20 Iron, 5 Fluoric acid, > 4 Silica, _ 1 Water, - 6 100 Bergmann, OpuscuL t. II. p. 345' Geognostic Situation. It occurs in veins in primitive transition and floet2 rocks, where it is generally associated with galena '° r lead-glance. Geographic Situation. It occurs along with galena or lead-glance, copp er ' pyrites, copper-green, red cobalt ochre, and heavy-spar, in Veins that traverse quartz-rock, at Clitlon Mine, near Tyndrum in Perthshire ; also in Flintshire. Very beau tiful specimens are met with at Ratieborziz in Bohemia, where it is associated with galena or lead-glance, grey cop per'