Elements of chemistry, in two volumes / by John Murray.

  • Murray, John.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Elements of chemistry, in two volumes / by John Murray. Source: Wellcome Collection.

    75/768 (page 63)
    G3 kingdom ; and its metallic base, which has been obtained by Sir H. Davy, is denominated Lithium. Lithina is extracted from these minerals by calcining them with nitrate or carbonate of barytes, then adding muriatic acid, which dissolves the barytes and alumina, and the lithina, leaving the silica. From this solution the barytes is precipitated by sulphuric acid, and the alumina by carbonate of ammonia; by evaporation, exposure to heat, and solution, sulphate of lithina is obtained nearly pure. Acetate of barytes precipitates the sulphuric acid, and acetate of lithina is obtained, which, by heat, is con- verted into carbonate. An easier process is recommend- ed by Berzelius, that of mixing spodumene or petalite in powder with twice its weight of fluor spar, and heating with sulphuric acid : the fluoric acid disengaged dissolves the silex, and escapes in the gaseous form ; and there re- mains only sulphates of lithina and alumina : by boiling with solution of ammonia, filtering, evaporating to dry- ness, and exposing to a red heat, pure sulphate of lithina is obtained, which may be converted into the carbonate. The alkali may be obtained pure by abstracting this acid. Lithina thus obtained is of a white colour: exposed to the air it absorbs carbonic acid, and becomes a carbonate. Its taste is caustic, and it changes the vegetable colours to a green. It is less soluble in water than potash or soda, and it is scarcely soluble in alcohol. From its low com- bining weight, its capacity of saturation, in relation to the acids, is superior to that of the other alkalis, a circum- stance which first led to its discovery. It consists, ac- cording to Dr Thomson, of one atom of lithium, 10, and one of oxygen, 8 ; hence its equivalent is 18. Ihe greater number of its salts are very soluble in wa- ter, and also very fusible. The Carbonate melts at a red heat: when heated in a platina crucible, it acts strongly