1. A heavy, malleable, ductile metal (Fe), of
which some papermaking beaters are constructed.
Minute specks of iron, which is chemically active,
sometimes break off, enter the papermaking slurry,
and become part of the paper. Iron may act as a
catalyst in the conversion of sulfur dioxide into
sulfuric acid, which is highly destructive to
paper. 2. An old measure of the thickness of a
leather, one iron being equal to 1/48 inch. See
SUBSTANCE TABLE .