The cognate industry of bleaching has been carried on since early in the 18th century, and large ironworks grew up in the latter half of the 19th century.
In the presence of water it frequently acts as a bleaching agent, the bleaching process in this case being one of reduction.
It is prepared on the industrial scale for the manufacture of sulphuric acid, for the preparation of sodium sulphate by the Hargreaves process, and for use as a bleaching-disinfecting agent and as a preservative.
The chief business is in butter, eggs, cattle and pigs, while bleaching, dyeing and shipbuilding are also carried on here.
The leading industries are ship-building, bleaching and the making of flax and glue.