124 URANIUM. —COLUMBIUM.— CERIUM, 



The pure metal is of a tin colour ; it is very 

 brittle, and is said to be magnetic. It is very in- 

 fusible, and is not altered by the air, though when 

 heated it is converted to an oxide. 



Besides its acid, it seems to combine with oxy- 

 gen in two other proportions, forming the green 

 and hroTdon oxides. 



URANIUM. 



This metal was discovered by Werner, in a mi- 

 neral called peclihlende, a blackish mineral re- 

 sembling pitch. 



Metallic uranium is brittle, and veiy infusible. 

 It is of a grey colour. It is obtained with extreme 

 difficulty, and little known. 



Its oxide is greenish-yellow, and is found native, 

 resembling green mica, and also in an earthy 

 state. 



COLUMBIUM. 



This metal was discovered by Mr. Hatchet in 

 analyzing an ore from North America. It has 

 since been found in the minerals called tantalite 

 and yttro-tantalite. The metal has been procured 

 by Berzelius. It is of an iron colour, hard and 

 brittle, and passes into an oxide at a red heat. 



Its oxide is white. Its combinations are little 

 known ; but it is one of the acidifiable metals. 



CERIUM, 



This metal was lately discovered by Berzelius, 

 in a mineral which has been called cerite. The 

 characters of the metal are imperfectly known, as 



