Barium

(bair'i-um.) [Gr. baros, heavy.] (Chem.) The metallic basis of the earth baryta, which latter body was first recognized as a distinct substance by Scheele in1774, and the metal obtained by Davy in 1808. It is of a silver-white color, rapidly oxidizing in the air. At. weight, 63.5; Symbol Ba. The Oxide of B., or Baryta, prepared by igniting nitrate of B., is a grayish, friable ma , soluble in water, forming a strongly alkaline solution. Sp. gr. 4-70; Form. Ba20. Sprinkled with a small quantity of water, it forms a white hydrate, with great evolution of heat and expansion of volume; Form. Ba HO; when di olved in water and crystallized, it separates in transparent colorle prisms, which contain 4 atoms of water. The native Carbonate of B., called Barolite or Witherite, occurring in small ma es of a light yellowish color and fibrous structure, and the Sulphate of B., which frequently occurs in the form of beautiful crystals, are found abundantly in lead mines, and are remarkable for their weight. B. compounds heated before the blow-pipe communicate a beautiful green color to the flame. All its soluble salts are highly poisonous. [s. 74]