Car·bon n.  Chem.
 1. An elementary substance, not metallic in its nature, which is present in all organic compounds. Atomic weight 11.97. Symbol C. it is combustible, and forms the base of lampblack and charcoal, and enters largely into mineral coals. In its pure crystallized state it constitutes the diamond, the hardest of known substances, occuring in monometric crystals like the octahedron, etc. Another modification is graphite, or blacklead, and in this it is soft, and occurs in hexagonal prisms or tables. When united with oxygen it forms carbon dioxide, commonly called carbonic acid, or carbonic oxide, according to the proportions of the oxygen; when united with hydrogen, it forms various compounds called hydrocarbons. Compare Diamond, and Graphite.
 2. Elec. A carbon rod or pencil used in an arc lamp; also, a plate or piece of carbon used as one of the elements of a voltaic battery.
 Carbon compounds, Compounds of carbon Chem., those compounds consisting largely of carbon, commonly produced by animals and plants, and hence called organic compounds, though their synthesis may be effected in many cases in the laboratory.
    The formation of the compounds of carbon is not dependent upon the life process.   --I. Remsen
 -- carbon copy, originally, a copy of a document made by use of a carbon paper, but now used generally to refer to any copy of a document made by a mechanical process, such as xerographic copying.
 Carbon dioxide, Carbon monoxide. Chem. See under Carbonic.
 Carbon light Elec., an extremely brilliant electric light produced by passing a galvanic current through two carbon points kept constantly with their apexes neary in contact.
 Carbon point Elec., a small cylinder or bit of gas carbon moved forward by clockwork so that, as it is burned away by the electric current, it shall constantly maintain its proper relation to the opposing point.
 Carbon paper, a thin type of paper coated with a dark-colored waxy substance which can be transferred to another sheet of paper underneath it by pressing on the carbon paper.  It is used by placing a sheet between two sheets of ordinary writing paper, and then writing or typing on the top sheet, by which process a copy of the writing or typing is transferred to the second sheet below, making a copy without the need for writing or typing a second time.  Multiple sheets may be used, with a carbon paper placed above each plain paper to which an impression is to be transferred.  In 1997 such paper was still used, particularly to make multiple copies of filled-in purchase invoice forms, but in most applications this technique has been superseded by the more faithful xerographic reproduction and computerized printing processes.
 Carbon tissue, paper coated with gelatine and pigment, used in the autotype process of photography. --Abney.
 Gas carbon, a compact variety of carbon obtained as an incrustation on the interior of gas retorts, and used for the manufacture of the carbon rods of pencils for the voltaic, arc, and for the plates of voltaic batteries, etc.
 ◄ ►