Potato-flour, which consists entirely of starch, makes a fine light bread, easily raised. Wheaten-flour, which contains little gluten, approaches in this respect to potato-flour. When the quantity of gluten is large, greater care is required to make a good light bread; but the bread from such flour is generally found to be more nutritive in its quality. A dough peculiarly rich in gluten is required for the manufacture of macaroni and vermicelli; such is said to be the flour naturally produced in southern Italy. By the above table it appears, that the use of richer animal, or poorer vegetable manures, would enable the farmer to raise, at his pleasure, either a rich macaroni wheat, or one poor in gluten suited for the makers of fancy bread. An equally striking effect is not produced upon other kinds of grain by varying the manure. Thus the proportions of starch and gluten in the dry grain of barley and oats, differently manured, were found to be as follows:— BARLEY. OATS. Starch. Gluten. Starch. Gluten. Blood, 66½ 6½ 60 5½ Night-soil, 66 6½ 60 5 Sheep dung, 66½ 6½ 61 4½ Horse dung, 66 6½ 61½ 4½ Cow dung, 69 3½ 62 3½ Vegetable manure, 69 3 66½ 2¼ Unmanured, 69½ 3 66½ 2¼ Though a variation in the proportion of gluten can be observed in both of these kinds of grain, according as one or other of the above kinds of manure was employed, yet neither the average quantity of gluten present in them, nor the variations to which the quantity is liable, are at all equal in amount to what are observed in the case of wheat. The malting of barley is known to be affected by a variety of circumstances. It should be so uniform in ripeness as to sprout uniformly, so that no part of it should be beginning to shoot when the rest has already germinated sufficiently for the maker’s purpose. On this perfect sprouting of the _whole_ depends in some degree the swelling of the malt, which is of considerable consequence to the manufacturer.