Clays are compact soils, not only by reason of the fineness of their particles, but because the predominating alumina swells and becomes pasty when it is wet, and thus prevents the passage of water through them. On this account, soils that are too compact, especially if they be underlaid by stiff clay subsoils, are not so well adapted to orcharding as those that are more porous. This is especially true of level lands, upon which water accumulates, to the great injury of the fruit-trees planted upon them; but even in hilly situations, with good natural surface drainage, the excess of clay is indicated by a "spouty" condition of the surface. So many varieties succeed in clayey lands, however, and some are so superior in their products when planted upon clays, that we need not be discouraged by this apparent difficulty; it may be overcome by the ingenuity of the skillful farmer. Thorough or under-drainage will remedy all the evils of clay soils, and bring out their superior advantages. This will be more fully explained in another place. Much may be done toward removing the redundant moisture, even in the flat clay lands of the prairies and other extended plateaus, by the simple means of ridging up the lands with the plow. What is familiarly called "back-furrowing" enables the plowman to raise a ridge upon which to plant his trees, and at the same time he opens a furrow for the escape of surface water. While a portion of the redundant moisture is thus removed, another great object of drainage is not attained: I allude to the aeration of the soil. * * * * * From what has been said upon a previous page, it might be inferred, that as the apple may be cultivated upon soils of such great diversity as those that occur over the range of territory indicated, as well as upon the western coast of this continent, and in the temperate regions of the Old World, the peculiar soils that are characterized by their underlying rocks would be equally acceptable, whether these were granites, shales, sandstones, or limestones. Such is not the fact, however, and we have found, in this utilitarian age, that geology has much to do with the planting of an orchard. There are varieties that succeed better upon one rock than upon another, and there are those that fail to be remunerative when transplanted to a rock, which to them is obnoxious, though it may be a very paradise to other varieties. * * * * * These observations are becoming a matter of great importance to orchardists, and we may hope that the study of this subject will be developed into some certain data, and that the future discussions of our pomological societies will furnish reliable information to orchard planters. FOOTNOTES: [19] See Lawrence Young's Experiments, in _Western Horticultural Review_, Vol. I. page 190, in Report of Kentucky State Fruit Committee to American Pomological Congress, for 1850.