Introduction to the study of inorganic chemistry / by William Allen Miller.

  • Miller, William Allen, 1817-1870.
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: Introduction to the study of inorganic chemistry / by William Allen Miller. Source: Wellcome Collection.

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    hydrogen a white, passing throiigli brownish-red into black. Their reactions with potassic iodide have been already noticed. (64) 2. Silver : Synib. Ag; Atom. IVt. 108.—This beautiful metal has been known and prized from the earliest ages. It is found commonly in the native state, and almost invariably accompanies galena in small quantity, in the form of sulphide. Mercury is used on a large scale for dissolving metallic silver, and separating it from earthy and other im- purities, but the metallurgic processes by which silver is extracted are somewhat elaborate, and are described in the text book on ‘ Metallurgy.’ Silver has a white colour, with a tinge of red. It po.s- sesses considerable tenacity and malleability, so that it may be drawn into verj' thin wire, and hammered into leaf. It is softer and more fusible than cojjper, and requires a tem- ])erature of 1023° C. for its fusion : though it is scarcely ^olatile in ordinary furnaces, it may even be made to boil under the very intense heat of the oxyhydrogen jet. As a conductor of heat and electricity, it is unsurpassed. It does not become oxidized at any temperature; but it has a sin- gular power of absorbing o.xygen when in a state of fusion, and giving up the gas suddenly when it solidifies. It com- bines slowly with chlorine, bromine, and iodine. Its alliac- tion for sulphur is very considerable ; the brown tarnish that silver acquires by exposure to the air is due to the formation of a thin film of argentic sulphide, in consequence of tiie action of the metal on the traces of sulphuretted hydrogen occasionally present in the air. This tarnish may be removed by rubbing the surface with a solution of ])otassic cyanide. Nitric acid is the best solvent for silver ; but it may also be dissolved by boiling sulphuric acid, with escaj)eof sulj)luirous anliydridc. Silver is seldom used alone, as it is too soft to resist wear • but when alloyed with cither 7I, or 10 [)cr cent.