Gallium

[From Gallia, in honor of France.] (Chem.) A metallic element (symbol Ga., atomic weight 70), discovered in 1875 by a French chemist, Lecoq de Boisbaudran, though predicted as ekaluminum by Men dele jeff when, in announcing his Periodic Law, he showed that an element must exist having intermediate properties between aluminum and indium. It is a triad element. It is obtained by di olving zinc blende in sulphuric acid and placing in the solution plates of zinc till the disengagement of hydrogen becomes slow, but is still perceptible, by which means the greater portion of the various metals contained in the ore is precipitated; the clear filtered liquid is then heated with a large exce of zinc; the resulting gelatinous precipitate, consisting chiefly of alumina, basic salts of zinc, and gallium, is redi olved in hydrochloric acid and again heated with zinc, which gives a precipitate in which the G. is more concentrated. This precipitate is redi olved in hydrochloric acid, the solution is treated with hydrogen sulphide, and the filtered liquid, after the expulsion of the H.S., is fractionally precipitated with ammonium carbonate, till the solution of the resulting precipitate in hydrochloric acid no longer gives any indication of the presence of G. when examined by the spectroscope. The precipitates are collected and di olved in sulphuric acid, and cautiously evaporated till the free sulphuric acid is expelled; the residue, when cold, is digested with water till it is di olved, the nearly neutral solution is boiled, the basic gallium sulphate is precipitated and filtered while hot, and then di olved in a small quantity of sulphuric acid, treated with exce of potash, till the precipitate is redi olved and then precipitated by a stream of CO.. Finally the G. oxide is redi olved in the smallest quantity of sulphuric acid, the solution mixed with exce of slightly acid ammonium acetate, then H.S gas is pa ed through the liquid; the filtered acetic solution is diluted with water, and heated to boiling, whereby the greater part of the G. is precipitated as oxide; this precipitate is filtered off bot, washed with boiling water and redi olved in sulphuric acid, and the solution mixed with a slight exce of potash and filtered, whereby a pure alkaline solution of G. in obtained. Metallic G. is gotten by the electrolysis of this alkaline solution, platinum electrodes being used, and the positive electrode being larger than the neg a tive on which the metallic G. is precipitated, which is detached by dipping the platinum plate in warm water and bending it backward and forward. G. is a silver white metal, which melts at 86° F. It is hard, very slightly malleable, and leaves a bluish-gray trace on paper. When melted it adheres to gla . It does not tarnish in the air. Its specific gravity is 5-95. It gives brilliant violet line in the spectrum. When heated in the air it oxidizes on the surface and does not volatilize. It di olves in hydrochloric acid with disengagement of hydrogen. It is scarcely attacked by nitric acid in the cold; but when heated it di olves slowly, with evolution of nitrous fumes. It forms salts. Gallivant', v. n. (Perhaps a corruption of gallant .) To roam about for pleasure, especially with or after one of the opposite sex; to flirt.-To run after trivial matters. Gallocy'an in, n. (Chem.) A coal-tar product used for dyeing cotton, silk or wool a violet color; called the "new fast-violet."