Nettle, or Urtica, L. a genus of plants, comprising 57 species, three of which are natives of Britain ; namely,

1. The urens, or LesseR StiNging Nettle, which is frequent on rubbish and cultivated lands ; it flowers from July to September— The leaves of this species, according to LinnAeus, are gathered and cut to pieces, in order to be mixed with the food of young turkies:— the whole plant is refused by every kind of cattle, and ought therefore to be carefully extirpated from pastures.

2. The dioica, or Common Nettle, grows on ditch-banks, and among rubbish ; it flowers in the month of July. This species has a square, firm stem, three or four feet high, with long-pointed, serrated leaves, that are furnished with stings, having at their base small vesicles full of a corrosive liquor; and which, on being touched, excite a blister, accompanied with a burning and painful sensation.

The Common Nettle, though generally considered as a noxious weed, is of extensive utility : its young tops may be boiled during the spring, and eaten as a substitute for greens ; being not only nourishing, but mildly aperient. In the Western Islands of Scotland, a rennet is prepared, by adding a quart of salt to three pints of a strong decoction of nettles 5 a table-spoonful of which is said to be sufficient to coagulate a bowl of milk. The leaves are employed for feeding poultry; and especially in the winter, when boiled, they promote the laying of eggs :—in a fresh state, they are refused by horses, sheep, goats, cows, and hogs; though asses devour them eagerly. When dry, they are eaten : by cows, for which they are an ex- . cellent food, increasing the quanti-ty, and improving the quality, of their milk : According toM.VAN Geuns, such fodder is an effectual preservative against the contagious distemper affecting horned cattle.

The roots of the Common Nettle, when boiled, communicate a yellow tinge to yarn. But the most valuable part, is its fibrous stalk or stem; which, on being dressed in a manner similar to flax or hemp, has, in some parts of Europe, been advantageously manufactured into cloth. This useful branch of industry has also been attempted in Britain, and a coarse kind of durable canvas was produced, which is considerably harder than the cloth manufactured from hemp or flax. As, however, this plant requires a rich soil to obtain it in any quantity, and, as a much greater degree of attention and accuracy is necessary in the operation of rating, than is requisite either for flax or hemp, Dr. Anderson is of opinion, that the cultivation of the nettle will be attended with difficulty. - From the rind, as well as the woody substance of the stalk, Dr. Schaeffer has produced a very good white writing paper ; though that manufactured by M. De Villette, in France, was of a dark-green colour.—The seeds, on expression, afford an useful lamp-oil.

In a medicinal view, the whole plant, and particularly the root, is esteemed to be diuretic ; and has, therefore, been recommended in the jaundice and in nephritic complaints.—A leaf, if placed on the tongue, and pressed against the roof of the mouth, is said to be efficacious in bleeding at the nose; and instances have occurred, in which paralytic limbs have been recovered by stinging them with nettles. If credit be due to some authors, the expressed juice of this plant is a valuable remedy to the asthmatic and consumptive.

3. The pilulifera, or Roman-Nettle, growing among rubbish, and on old walls. It is fou d chiefly in the vicinity of Yarmouth, and on the eastern coast of England: it flowers in the month of August.

Both the last mentioned species possess similar properties ; and, as the Common Nettle, in particular, acquires the height of six feet, when sown in September or October, on an indifferent soil, Funke strongly recommends its culture; nay, he maintains, that after the second year of its growth, it thrives rapidly, reproduces itself annually, and may be mown two or three times eyery year. In this respect, it promises to become an excellent fodder for cattle.

Nettle. - Some interesting experiments have lately been made by M. Zannetini, in Italy; from which it appears, that the flowers is a lever, in which is inserted an iron pin ; that passes through the centre of the bed-stones, and communicates with various machinery, that sets the whole in motion. - Our limits not permitting us to detail its constituent parts, we can only add, that a drawer containing three sieves is placed under the stones, for the reception and sifting of the meal. The price of this mill is 16, or, with the drawers and sieves, 17 guineas; and the machine is asserted to grind six bushels of grain, in one day. with perfect ease. - A farther account of Mr. W.'s ingenious contrivance may be found in the 38th vol. of " Annals of Agriculture, " where his description is illustrated with an appropriate plate - See also Water-mills; in this Appendix.