BARLEY, in chemistry, is the seed of the hordeum vulgare, which will be de scribed hereafter. Great crops of it are reared annually, partly as an article of food, and partly as a material from which malt liquors and ardent spirits are drawn. This species of corn has been examined of late with considerable attention by chemists, partly in order to form correct conceptions, if possible, of the nature of the process of fermentation, and partly to ascertain the constituents of barley. Fourcroy and Vauquelin published seve ral ingenious remarks and experiments on it in 1806, and Einhof published a still more elaborate analysis about the com mencement of the same year, having ex amined this grain in different stages of its growth, and after it was fully ripe. When unripe barley-corns are triturated with water, the liquid acquires a milky colour. If this process be continued, adding fresh portions of water as long as the liquid passes off muddy, there re mains only a green husky matter. When this matter is macerated a sufficient time in cold water, it acquires a greenish grey colour, and when dry has the appearance of vegetable fibre. The water in which it was macerated, when boiled, deposits a few flakes of albumen, and when evapo rated to dryness, leaves a small portion of extractive. The water with which th e bar ley was at first triturated is at first milky,
. and gradually deposits a white powder ; yet it does not become transparent, though allowed to stand a considerable time. When filtered, it passes through transpa rent, while a slimy substance, of a green ish grey colour, remains upon the filter. This substance possesses the properties of gluten. When the solution, now trans parent, and of a yellowish colour, is boil ed, it deposits flakes of albumen. It red dens litmus paper, and is strongly preci pitated by lime-water, nitrate of lead, and sulphate of iron, indicating the presence of phosphoric salts. The liquid being eva porated to the consistence of a syrup, and the residue treated with alcohol, the solution diluted with water, and the alco hol distilled off, to separate some gluten which still remained, a syrupy matter was obtained having a sweet taste, which was considered as the saccharine matter of the barley. A portion refused to dissolve in alcohol. This portion was considered as extractive. The white powder, which precipitated from the water in which the barley had been originally triturated, pos sessed the properties of starch.
BARLEr-corn, the least of our long mea sures, being the third of an inch.