MANUAL OF NATURAL HISTORY. 607 



the addition of nitre ; solutions of its salts 

 are green. Symb. Ni. 



9. Family. — Cobaltides. Minerals containing com- 



pounds of Cobalt. Occur 1, as Sulphuret, or 

 " Syepoorite," massive, sp. gr. 5-4, yellowish 

 steel-gray, with magnetic pyrites at Syepoor ; 

 2, with Sulphur and Arsenic, or " Cobalti- 

 glance," hemihedral, sp. gr. 6-29, fl. = 5*5 ? 

 metallic, reddish, brittle, often with copper 

 pyrites ; 3, as Arseniate, or " Cobalt-bloom/" 

 in oblique prisms, or botryoidal and fibrous, 

 sp. gr. 2*9, H. = 2-2*5, reddish, sectile, with 

 other cobalt ores. Oxide of cobalt forms 

 with borax a deep blue glass ; solutions of 

 the salts are bright red, when anhydrous they 

 are blue. Symb. Co. 



10. Family. — Manganides. Minerals containing 



compounds of Manganese. Occur, ] , rarely 

 as Sulphur et or Arseniuret 2, as Oxide, 1, 

 Anhydrous "peroxide or "Pyrolusite," trime- 

 tric, sp. g. 4-8, H. = 2-2*5, blackish, metallic ; 

 2, Sesquioxide or " Hausmannite/' dimetric, 

 sp. gr. 4*7, H. = 5-5*5, sub-metallic, brownish- 

 black ; 3, Hydrated Sesquioxide or " Man- 

 ganite," trimetric, sp. gr. 4*3, H. = 4, iron- 

 black, sub-metallic ; 3, combined with Baryta 

 or " Psilomelane," massive and botryoidal, 

 sp. gr. 4*4, H. = 5-6, sub-metallic, brownish- 

 black ; 4, with iron, cobalt, or copper, as 

 "Wad," "Earthy Cobalt," or " Cupreous- 

 Manganese," amorphous, sp. gr. 3-3*7, 



