TJTANIUM.'— CHROMIUM. 123 



dissolving the metal in nitromuriatic acid, and di- 

 luting the solution with a large quantity of water. 



Tellurium combines with hydrogen, and with it 

 forms a gaseous substance, called telluretted hy- 

 drogen. 



This metal is scarce, and its combinations yet 

 little known. 



TITANIUM. 



This metal is rare. It was discovered in a 

 mineral, found in Cornwall, called menachanite. 

 It was afterwards procured from another mineral, 

 titanite, and some others. The metal when pure 

 is brittle, very infusible, of a brass or copper co- 

 lour, easily tarnishes in the air, and oxidizes by 

 heat. There appear to be three oxides of titanium, 

 the blue, the red, and the xvhite. 



The ores of titanium are either pure crystallized 

 oxide, or the oxide united to iron, or to silex. 



CHROMIUM. 



This substance, little known in the metallic state, 

 is important on account of the fine pigments it 

 affords. It is capable of being acidified, and the 

 chromic acid forms salts. The beautiful mineral 

 called red-lead of Siberia, is a chromate of lead. 

 This is now artificially prepared, and is a very va- 

 luable and beautiful yellow pigment. The chro- 

 mic acid also unites to iron, the chromate of iron 

 being found native ; and it is from this that the 

 chromic acid is procured and united to lead, to 

 form the chromate of lead. Chromate of iron is, 

 therefore, much sought after, and is found in 

 greatest abundance in America, from whence our 

 colour-makers chiefly procure it. 



