URANIUM. U

Atomic Weight 238.5. A metallic element, belonging to the chromium group. It was first isolated in 1842 by E. M. Peligot, although its existence had been recognized many years prior to that date. It was named in 1789 after the planet Uranus, discovered in the year 1781, by Henschel. Its chief ore is pitch-blende, and it po e es radio-active properties. It is a white, heavy metal, capable of taking a high polish, with a specific gravity of 18.7 and a melting point of 1500°C. The metal forms two series of salts, uranous and uranyl, but the trioxide also has acidic properties, forming salts with metallic bases, such as sodium diuranate, which is used for coloring gla and pottery. Uranium and its compounds are also used in the manufacture of steel, and of incandescent mantles.