ACHING, the process of whitening or depriving objects of colour, an
operation incessantly in activity in nature by the influence of light,
air and moisture. The art of bleaching, of which we have here to treat,
consists in inducing the rapid operation of whitening agencies, and as
an industry it is mostly directed to cotton, linen, silk, wool and other
textile fibres, but it is also applied to the whitening of paper-pulp,
bees'-wax and some oils and other substances. The term bleaching is
derived from the A.-S. _blaecan_, to bleach, or to fade, from which also
comes the cognate German word _bleichen_, to whiten or render pale.
Bleachers, down to the end of the 18th century, were known in England as
"whitsters," a name obviously derived from the nature of their calling.

The operation of bleaching must from its very nature be of the same
antiquity as the work of washing textures of linen, cotton or other
vegetable fibres. Clothing repeatedly washed, and exposed in the open
air to dry, gradually assumes a whiter and whiter hue, and our ancestors
cannot have failed to notice and take advantage of this fact. Scarcely
anything is known with certainty of the art of bleaching as practised by
the nations of antiquity. Egypt in early ages was the great centre of
textile manufactures, and her white and coloured linens were in high
repute among contemporary nations. As a uniformly well-bleached basis is
necessary for the production of a satisfactory dye on cloth, it may be
assumed that the Egyptians were fairly proficient in bleaching, and that
still more so were the Phoenicians with their brilliant and famous
purple dyes. We learn, from Pliny, that different plants, and likewise
the ashes of plants, which no doubt contained alkali, were employed as
detergents. He mentions particularly the _Struthium_ as much used for
bleaching in Greece, a plant which has been identified by some with
_Gypsophila Struthium_. But as it does not appear from John Sibthorp's
_Flora Graeca_, edited by Sir James Smith, that this species is a native
of Greece, Dr Sibthorp's conjecture that the _Struthium_ of the ancients
was the _Saponaria officinalis_, a plant common in Greece, is certainly
more probable.

In modern times, down to the middle of the 18th century, the Dutch
possessed almost a monopoly of the bleaching trade although we find
mention of bleach-works at Southwark near London as early as the middle
of the 17th century. It was customary to sen