For the preparation of kelp these plants are dried, by exposure for some time to the sun and air. They are then burnt by degrees in a kelp furnace, which is generally a round hole dug in the earth. When the furnace is nearly filled with the remains of the burnt sea-weeds, the whole is briskly agitated with a rake or hook, till it is compacted, or becomes of a shining glutinous consistence, in appearance not unlike melted iron. It is then allowed to cool, and is afterwards placed in storehouses for exportation. In this state it is an impure kind of carbonat of soda. In the Orkney Islands every consideration is sacrificed to the making of kelp, nearly 3,000 tons of which are annually sent to market and sold at Leith, Newcastle, and other places, at the rate of from seven to ten pounds per ton of twenty-one hundred weight. The inhabitants of Gothland boil this plant with coarse meal, as food for swine; and the poorer classes of Scania thatch their cottages with it, and also employ it as fuel. In the Hebrides it is customary to dry cheese, without using any salt, by covering it with the ashes of the bladder fucus, which abound in saline particles. This and other sea-weeds serve as a winter food for cattle, which regularly frequent the shores for them at the ebb of the tide: they are also used as manure for land. A soapy liquor which is found in the bladders of this plant is sometimes externally applied as a medicine for dispersing scrofulous and scorbutic swellings, by simply bruising them in the hand and rubbing them on the parts affected. When this plant is calcined or burnt in the open air, a black and saline powder is produced, which, under the name of _vegetable æthiops_, has been recommended as a dentrifice, and for other uses. 289. _EATABLE WINGED FUCUS, or BLADDERLOCKS_ (Fucus esculentus), _is a simple, undivided, and sword-shaped sea-weed, which is olive-coloured, and sometime several yards in length_. _Its stem is four-cornered, runs through the whole length of the leaf, and is winged at the base._ This plant, which is very common on some of the shores of Scotland, and also on those of Cornwall, and several parts of North Wales, is a grateful food to cattle; and its stalk, when boiled, constitutes a very favourite dish in Scotland. The proper season for gathering it is the month of September, when it is in higher perfection than at any other time of the year. 290. _SWEET FUCUS_ (Fucus saccharinus) _is a simple, undivided, and sword-shaped sea-weed, without any rib, of leathery consistence, and tawny green colour; and frequently five or six feet in length_. _Its stalk is round and hard._