Native Argill, ift Tribe. Native ArgHl. Lac Lunae of fome. Reinethon Erde of Werner. Colour, pure white. Found in neßs, in compa&ed rounded kidney- form maffes. Luflre, 0. Tranfparency, o. Fraäure, earthy. Fragments, 0. Hardnefs, 4, brittle. Sp. gr. moderate. Feels meagre, but foft. Adheres very flightly to the tongue, ßains ve- ry flightly. Does not readily diffufe itfelf in water. Infufible at 166 0 . It fometimes effervefees with acids, being fatu- rated with fixed air, a circumftance which is rarely obferved in earths of the argillaceous kinds ; and to this union we may aferibe its meagre feel, flight adherence to the tongue, and litde attrac- tion to water. It is not perfeflly pure ; for, it was found by Mr. Schreiber to contain a very fmall proportion of aerated calx, and in forns fpecimens a little gypfum,- alfo ferne feeble traces of ironj but (as it leems) no fiiex, which diftiu- guiflies it from clays properly fo called. It has been found at Halles, in Magdeburgh, and, as fome fay, at Verona, Of