Limestone. 495 Phyjical Character. « Many varieties of calc fpar, as Mr Hatchett informs- become phofphorefcent when laid on burning c °al. Iiauy has made a fnmlar obfervation. Geogiiostic Situation. It occurs venigenous in almoft every rock from granite to the neweft floetz trap \ it is even found in Pluvial land. The veins are lonntimes very new, b ut others are foold as to be nearly of cotemporaneous formation with the rocks in which they run It alfo frequently lines drufy cavities. 1 Occurs in a great variety of mineral veins, and in Uiany of them it chara&erifes the formation. Geographic Situation. It is fo univerfally diffributed that an enumeration °f its localities would be unneceffary in a work like l be prefent; therefore 1 fhall only mention, that many °f its ntoil beautiful and rare cryftallizations are found in Derbyfhire in England, in Ireland. Saxony, ^ance and Spain; each country affording peculiar Var ieties, which no doubt, in many cafes, correfpond ' v »h the different mineral vein formations in the dif- lri &s where they occur. Obfet vatiens