Whatever may be the original source of our known species of grain, and of their numerous varieties, it cannot be doubted that their existence, at the present time, is a great blessing to man. Of wheat there are upwards of a hundred and fifty known varieties, of barley upwards of thirty, and of oats about sixty. While the different species--wheat, barley, and oats--are each specially confined to large but limited regions of the earth's surface, the different varieties adapt themselves to the varied conditions of soil and climate which exist within the natural geographical region of each, and to the different uses for which each species is intended to be employed. Thus the influence of variety upon the adaptation of the oat to the soil, climate, and wants of a given locality, is shown by the following observations:-- "The Siberian oat is cultivated in the poorer soils and higher districts, resists the force of the wind, and yields a grain well adapted for the support of farm-horses. The straw is fine and pliable, and makes an excellent dry fodder for cattle and horses, the saccharine matter in the joints being very sensible to the taste. It comes early to maturity, and hence its name." The Tartarian oat, from the peculiarity of its form, and from its "possessing a beard, is of such a hardy nature as to thrive in soils and climates where the other grains cannot be raised. It is much cultivated in England, and not at all in Scotland. It is a coarse grain, more fit for horse-food than to make into meal. The grain is dark coloured and awny; the straw coarse, harsh, brittle, and rather short." The reader will see from this extract that the English "food for horses" is, in reality, not the same thing as the "chief o' Scotia's food;" and that a little agricultural knowledge would have prevented Dr Johnson from exhibiting, in the same sentence, an example of both his ignorance and his venom. Variety affects appearance and quality; and how these are to be consulted in reference to the market in which the grain is to be sold, may be gathered from the following:--