3 3 2 Sirontbian Genus. SIXTH GENUS. Stronthian Earth. ift Species. Combined with fixed air, Stronthianite. ITS colouris light, ot whitifh greea. It is found in large fhapelefs mafles. Its luftre, from 2 to 3. Its tranfparency, 2. Its fradture, thick ftriated, fometimes prefent- ing diftindt columnar concretions. Its hardnefs, 5. Its fpec. grav. from 3,4 to 3,644« It burns to lims in a heat of 140°, and eafily vitrifies with the clay of the crucibles. It effervefces with the nitrous and muriatic acids, and forms with them eafily cryftallizable falts, but which are ptecipitable by barytic lime water. seventh