I. While I doubt that there is _any_ land above water that would not be improved by a good system of underdrains, I am sure that there is a great deal that could not at present be drained to profit. Forests, hill-side pastures, and most dry gravelly or sandy tracts, I place in this category. Perhaps one-third of New-England, half of the Middle States, and three-fourths of the Mississippi Valley, may ultimately be drained with profit. II. _All_ swamp lands without exception, nearly all clay soils, and a majority of the flat or gently rolling lands of this country, must eventually be drained, if they are to be tilled with the best results. I doubt that there is a garden on earth that would not be (unless it already had been) improved by thorough underdraining. III. The uses of underdrains are many and diverse. To carry off surplus water, though the most obvious, stands by no means alone. 1. Underdrained land may be plowed and sowed considerably earlier in Spring than undrained soil of like quality. 2. Drained fields lose far less than others of their fertility by washing. 3. They are not so liable to be gullied by sudden thaws or flooding rains. 4. Where a field has been deeply subsoiled, I am confident that it will remain mellow and permeable by roots longer than if undrained. 5. Less water being evaporated from drained than from undrained land, the soil will be warmer throughout the growing season; hence, the crop will be heavier, and will mature earlier. 6. Being more porous and less compact, I think the soil of a drained field retains more moisture in a season of drouth, and its growing plants suffer less therefrom, than if it were undrained. In short, I thoroughly believe in underdraining. IV. Yet I advise no man to run into debt for draining, as I can imagine a mortgage on a farm so heavy and pressing as to be even a greater nuisance than stagnant water in its soil. Labor and tile are dear with us; I do not expect that either will ever be so cheap here as in England or Belgium. What I _would_ have each farmer in moderate circumstances do is to _drain his wettest field_ next Fall--that is, after finishing his haying and before cutting up his corn--taking care to secure abundant fall to carry off the water in time of flood, and doing his work thoroughly. Having done this, let him subsoil deeply, fertilize amply, till carefully, and watch the result. I think it will soon satisfy him that such draining pays.