EARTH COAL OR EARTHY BROWN COAL. 373 then made into bricks, and dried. Sometimes it is inter mixed with small black coal, to increase the intensity of the heat. Its ashes are used with advantage as a ma nure ; and a colour resembling umber is prepared from it. Observations. 1. It passes into Bituminous Wood, from which it differs principally in its state of aggregation. 2. Umber or Cologne Earth is said to be a variety of earth coal. 3. When much iron-pyrites is dispersed through it, alum is prepared from it, as is the case<at Muhlbach, and Komothau in Bohemia. 4. Its name is derived from its state of aggregation. Third Subspecies. Alum Earth. Alaunerde, Werner. fcrra aluminaris, Wall. t. ii. p. 32.-—Alaunerde, Wid. s. 398.— Id. Estner, b. ii. s. 647. Id. Emm. b. ii. s. 299.—Aluminite biturnincux, Lam. t. ii. p. II6.—Ln terre alumineuse, Brock. t. i. p. 383.—Alaunerde, llcitss, b. ii. 3. s. 152. Id. Lud. b. i. s. 110. Id. Suck. 2ter th. s. 528. Id. Bert. s. 218. Id. Mohs, b. ii. s. 311. Id. Leonhard, label, s. 48. Id. Karsten, Tabel. s. 58—Erdige Afterkohle, Ilaus. s. 116.—Alaunerde, Bens, b. ii. s. 1063. External Characters. Its colours are blackish-brown, and brownish-black. A a 3 It
