( 5°5 ) t FOURTH SPECIES. Schaum Earth, or Foaming Earth. S chaumerde,—Werner. id. Emm. b. i. f. 484,—Schaum Kalk, Lett. 2. p- 39^. Silvery Chalk, Kina. vol. 1. p. 78.,-L’ecume de terre, Broch. t. 1. p. 557* External Charatters. I It has a very light yellowifh, nearly filver "diite colour, and fometimes approaches to greyifh 'vhite. Occurs maffive and diffeminated, alfo fometimes loofe and compofed of fine Icaly particles, or inter mediate between friable and loofe. Its luftre is intermediate between fhining and gliftening; the loofe varieties are glimmering, and intermediate between femi-metallic and pearly, but in cline more to the latter. Generally