616 MANUAL OF NATURAL HISTORY. 



light steel-gray; 2, with Platinum as 

 " Platin-Iridium," in small grains, sp. gr. 

 = 16-17, white. Fusible only before the 

 oxy-hydrogen blowpipe. Solutions of its 

 salts present varied colours. Symb. Ir. 



2. FAMILY. Osmiides. Minerals containing Os- 



mium. Occur with ores of Iridium, and 

 Platinum, sp. gr. = 7. Fusible before the 

 oxy-hydrogen blowpipe. Forms with oxy- 

 gen a volatile acid, with a pungent smell 

 resembling that of chlorine. Symb. Os. 



3. FAMILY. Vanadiides. Minerals containing com- 



pounds of Vanadium. Occur as Vanadic 

 acid combined, 1, with lead or "Vanadinite," 

 hexagonal, H. = 2*5 3, sp. gr. = 6'9, brown- 

 ish-yellow ; 2, combined with iron or with 

 copper. Dissolves in Nitro-hydrocliloric acid ; 

 forms coloured solutions. Symb. V. 



4*. FAMILY. Telluriides. Minerals containing 

 Tellurium, either native or in combination. 

 Occur 1, pure as "Native Tellurium/' lamellar 

 or granular, H. = 2 2'5, sp. gr. = 6'2, white; 

 2, in combination with other metals as gold 

 or " Graphic Tellurium/' prismatic, H.= 1/5-2, 

 sp. gr. 5'7 8*2, gray; also with bismuth, 

 silveTj and lead. Tellurium volatizes before 

 the blowpipe, emitting no odour. Symb. Te. 



5. FAMILY. Bismuthides. Minerals containing 

 Bismuth either native or variously combined. 

 Occur 1, pure or "Native Bismuth," rhom- 

 bohedral, H. = 2 2 '5, sp. gr. = 9 '7, reddish- 



