516 MINERALOGT. 



18. Titanium. This Metal is of a reddish Copper colour, 

 and so extremely difficult of fusion, that attempts to re- 

 duce it to a pure Metallic state, have rarely succeeded. 



It is found combined with oxyde of Iron, Manganese, 

 Silex, &c. ; it was formerly employed in painting on porce- 

 lain, but has fallen into disuse from the want of uniformity 

 in its colour. 



19. Tantalium. This is a very rare Metal, it is about six 

 times heavier than water, its external has a slight 

 Metallic lustre, but the interior is dull and nearly 

 black. ; 



Tantalium has only been found in Sweden and Finland, 

 combined viith the oxydes of Iron and Manganese, as also 

 with the rare earth Yttria. 



20. MoLYBDENA. Like the last this is exceedingly rare, has 

 never been found pure, and is with difficulty reduced to 

 a pure state, having only been obtained in brittle in- 

 fusible grains. 



It is found in a Mineral state combined with Sulphur, and 

 in the Acid state with Lead. 



21. Tungsten. This is a hard, brittle, granular MetuI, of 

 a light steel grey colour, and brilliant Metallic lustre. 



It is found combined wi*b oxyde of Iron, Manganese, and 

 Silex, and occurs in most places abounding with Tin ; it has 



