POTASSIUM. 439 



IV. Metals proper, of which the protoxides are isomorphous 

 with magnesia, with bismuth nine metals : 



Manganese. 

 Iron. 

 Cobalt. 

 Nickel. 



Cadmium. 

 Copper. 

 Lead. 

 Bismuth. 



Zinc. 



V. Other metals proper having isomorphous relations with 

 the magnesian family seven metals : 



Tin. 



Titanium. 



Chromium, 



Tungsten. 



Molybdenum. 



Tellurium. 



Vanadium. 



VI. Metals isomorphous with phosphorus two metals : 



Arsenic. Antimony. 



VII. Metals proper, not included in the foregoing classes, of 

 which the oxides are not reduced by heat alone four metals : 



Uranium. 

 Cerium. 



Lantanum. 



Columbium or Tantalum. 



VIII. Metals proper, of which the oxides are reduced to the 

 metallic state by heat, (noble metals) three metals : 



Mercury. Gold. 



Silver. | 



IX. Metals peculiar to native platinum (noble metals) five 

 metals :* 



Platinum. Osmium. 



Palladium. Rhodium. 



Iridium. 



ORDER I. 



METALLIC BASES OF THE ALKALIES. 



SECTION I. 

 POTASSIUM. 



Syn. KALIUM. Eg. 490 or 39.3; K. 



The alkalies and earths have long been named and distin- 

 guished from each other, but they were not known to be the 

 oxides of peculiar metals till a recent period. The terms ap- 



