Buck-Wheat, the Polyg-num. fagapyrum, L. a species of the Persicaria, also called snakeweed, bucke, branks, French wheat, or crap. As this useful plant requires no botanical description, we shall proceed to state its most approved method of culture, and important uses in agriculture : both subjects being intimately connected.

Buck-wheat was introduced into Europe nearly four centuries since ; and, according to Gerards Herbal, cultivated in England, about the year 1597.—It is a native of the northern parts of Asia. During the last thirty years it has excited the attention of able agriculturists, who have furnished us with the following result of their experience. This grain delights in a mellow, dry, loose, sandy soil, but does not thrive so well in a free loamy stone-brash, and should never be sown in wet, poachy ground. It requires little or no manure, but frequent sun-shine. On heaths newly ploughed up, the turf of which has been burnt, or that have been manured with wood-ashes, its vegetation is luxuriant. The proper season for sowing is the last week in May, or the beginning of June; and though it may be sown much earlier or later, yet, in the former case it is exposed to the night-frosts of April and May, or, in the latter, it may be too late for arriving at maturity. In the year 1/8/, however, a crop of buck wheat was obtained, that had been sown so late as the 22d of July. A shower of rain, alter the seed is harrowed in, greatly promotes its growth, and it generally appears above ground in five or six days.

Buck-wheat is in flower throughout the summer, and would yield much larger crops, if all the grains would uniformly ripen, and could be collected at the same time. From one to three bushels are sown on each acre, in this country : and the Germans calculate sixty pounds weight to every hundred square rods of land. Three months only are required for bringing it to maturity, and it produces from twelve to twenty-fold. The most economical manner of harvesting this grain is, by pulling it out of the ground, like flax, stripping it of the seeds by the hand, and collecting them into aprons. Thus all the ripe seeds are easily separated, before they are put into bags, to be conveyed to the granaryj while the straw is left, till dry, in the field. In this state, it affords an excellent substitute for hay; and it is affirmed, that the German farmer obtains, at less expence than by mowing and drying the whole, in the usual way, ten times the quantity of corn.

Another variety of this grain was, about a century ago, introduced into Germany, and has lately also been cultivated in Britain, known by the name of SiberianBuch-wheat. It possesses considerable advantages over the former ; because it is not only a fourth part heavier in the grain, but also more palatable, and, in this respect, resembles rice. It thrives in the poorest soil, is not affected by cold, and, being more disposed to branch out, and spread its stalks, requires scarcely one half of the seed necessary for the culture of the preceding species.

From repeated experiments, made in this country, it appears that the culture of buck-wheat ought, in many cases, to be adopted in preference to a summer-fallowing; as the crop produced is not only so much clear gain, but also affords a considerable quantity of straw, for fodder and manure ; beside which, it is a more advantageous preparation for the next crop. There will be sufficient time to sow the land with buck-wheat after spring feedings, a crop of turnip-rooted cabbage, or vetches. When sown in July, buck-wheat is an excellent sheltering crop to clover 3 and two crops of this grain have, in favourable years, been obtained from the same land. Mr. Arthur Young, in the sixth volume of the "Annals of Agriculture, " has inserted an instructive paper, communicated by the Rev. R. Moseley (Sept. 11th, 1786), from which we learn the following valuable facts: That three crops were sown on the same ground, between autumn and autumn, with only three ploughings, namely, winter-tares in September, with one ploughing, which were reaped early in the succeeding summer ; then immediately buck-wheat was sown, after one ploughing and harrowing : in September the buck-wheat was ploughed in, and wheat was sown on this one ploughing, the crop of which was great. Thus, says Mr. Young, as the spring advances, and the sun becomes powerful enough to exhale the humidity of the land, the crop also advances, and screens it from the action of his beams. The weeds in the soil vegetating with the young tares, are either strangled by their luxuriance, or cut off with them, before they produce seed. This crop is cleared from the land so early, that the soil would remain exposed to the sun for three months, in the most scorching heat of the summer ; and, if thus left exposed, the three ploughings would be hurtful to the soil, except that they might destroy some weeds. Hence, to give one ploughing immediately, and harrow in buck-wheat, saves expence; and the growing herbage shades the earth, when it most requires to be protected : by this management, a dressing of manure is gained at the cheapest possible rate. In short, to introduce a system more complete, is not in the power of science.

It appears to be undecided, whether buck-wheat improves or impoverishes the soil. There can be no doubt that it will produce the latter effect, like all plants mat are suffered to run to seed; and, on the contrary, that it renders the soil more fertile, when ploughed in, before the seeds are formed. Such, atleast, is the opinion of Mr.BoRDley, a respectable American farmer, and Mr. Farrer, a considerable corn-factor in London. But Mr. Young, whose knowledge and reputation are equally great, observes, on the strength of his own experience, that this plant ameliorates the soil insomuch, that the farmer may have any crop after it, especially ivheat ; for which reason it is (1784) commonly cultivated about Norwich,

One of the principal uses of buck-wheat in this country, is that of feeding horses. Mr. Farrer advises it to be mixed with bran, chaff, or grains, either whole or broken in a mill. When consumed in the state of grass, it flushes cows with milk ; hence it is presumed, that the meal mixed with grains would have the same good eff ct, and enrich the milk. One bushel of it is equal to two bushels of oats, even mixed with beans, and four times the quantity of bran ; it will be full food for a horse a-week, and require much less hay. According to his experience, eight bushels of luck wheat meal will go as far as twelve bushels of barley meal. But the American farmers assert, that it is an improper food for horses on a journey, or employed in active labour ; though its, meal when mixed with other corn, or cut straw, answers well even for horses in a slow draught. It is unquestionably a cheap corn, subservient to many good purposes, and peculiarly excellent for fattening hogs and poultry : the former are said to become intoxicated by eating the whole plant; but no such effect takes place from the seeds alone. Dr. Withering observes, that sheep feeding upon this vegetable, become unhealthy; but it is relished by cows and goats.

For culinary purposes, also, the grain of the buck-wheat is used in various forms, and affords a nutritious meal, which is not apt to turn sour on the stomach. Mixed with barley, it is, in Tuscany, baked into bread, which possesses the property of retaining its moisture much longer than that of pure wheat ; and though of a darker colour, it is equally nourishing. In Germany, a very palatable grit, or a granulated meal, serving as an ingredient in pottage, puddings, etc. is prepared of buck-w heat; and if the seed be pure, the produce of each bushel is ten pecks. In the electorate of Brandenburgb, not only ale and beer is brewed from a mixture of it with malt, but likewise a very excellent spirit of a blueish shade is obtained by distillation ; the flavour of which resembles that of French brandy. The taste and colour of stale beer, may be much improved by adding a small quantity of the flour of this grain.

From this, as well as the preceding species of buck-wheat, the Tar-tars prepare a delicious food, by simply blanching the seeds, with-out mills or ovens, in a manner very ingenious, and applicable to most other species of grain. They first pour cold water on the seed, and stir it well, in order to bring the light and imperfect grains to the top, which are thrown away with the water. Then the wet corn is put in sacks, where it is suffered to remain from ten to twelve hours : thus, after swelling a little, it is roasted over a slow tire in iron pans, and continually stirred till the grain becomes tolerably hard, so that it feels tough and clastic between the teeth. In this manner, the husks soon crack, and may easily be separated from the kernel, in one of the plainest domestic implements, a wooden mortar, or a bruising machine made of the hollow trunk of a tree. By this process, the grain acquires a yellow transparent appearance, and is much improved in taste.

From the fresh blossoms of these plants, Dambourney dyed wool, prepared with bismuth and tin, of a beautiful brown colour; and, from the dryed flower-bundles, different shades of green. Those of the Siberian species, in particular, yielded a fine yellow, which, on boiling the wool still longer in the dye, changed into a golden tint, and at length assumed a brilliant yellow.

There is a third species of buck-wheat, the culture of which has lately been strongly recommended by Professor Pallas, and Dr. Withering; and which we shall presently describe.

Buck-Wheat, the Climbing, black bindweed, or climbing snakeweed ; the Polygonum convolvulus, L. a native vegetable, growing about corn-fields, gardens, and hedges; it flowers in June and July. Its seeds are as good as those of the two preceding species, are produced in greater quantity, may be more easily collected, as they ripen more uniform y, and the plants bear cold better than the exotics before mentioned. According to Linnaeus, cows and goats eat it, but sheep, swine, and horses, refuse it.

Its culture in fields is, however, attended with this inconvenience, that its creeping stalks must be supported by brush-wood, and it is consequently better a apted for being cultivated in gardens.

It is remarkable, that most British and foreign writers indiscrimi-nately recommend the culture of the buck-wheat, likewise, on account of its Bowers, which are very grateful, and beneficial to bees ; and that Dr. Darwin, in particular (see page 230 of this Encyclopaedia), mentions a species of buck-wheat, the Polygonum, melitmpyrum, of which we can find no account in the botanical works of this country: with deference to his profound knowledge of natural history, we are almost inclined to think, the Doctor alludes to a very different species of buck-wheat (perhaps cow-wheat) that is not cultivated in Britain.