Why does it prevent the throwing out of grain in winter? Why does it enable us to work sooner after rains? Why does it keep off the effects of cold weather longer in the fall?] 11. _Soils are, thereby, rendered earlier in spring_, because the water, which rendered them cold, heavy, and untillable, is earlier removed, leaving them earlier in a growing condition. 12. _The throwing out of grain in winter_ is prevented, because the water falling on the earth is immediately removed instead of remaining to throw up the soil by freezing, as it always does from the upright position taken by the particles of ice. 13. _We are enabled to work sooner after rains_, because the water descends, and is immediately removed instead of lying to be taken off by the slow process of evaporation, and sinking through a heavy soil. 14. _The effects of cold weather are kept off longer in the fall_, because the excess of water is removed, which would produce an unfertile condition on the first appearance of cold weather. The drains also, from causes already named (3), keep the soil warmer than before being drained, thus actually lengthening the season, by making the soil warm enough for vegetable growth earlier in spring, and later in autumn. [How does it prevent lands from becoming sour? Why does it hasten the decay of roots, and the comminution of mineral matters? How does it prevent the abstraction of heat from the soil?] 15. _Lands are prevented from becoming sour by the formation of acetic acid_, etc., because these acids are produced in the soil only when the decomposition of organic matter is arrested by the _antiseptic_ (preserving) powers of water. If the water is removed, the decomposition of the organic matter assumes a healthy form, while the acids already produced are neutralized by atmospheric influences, and the soil is restored from sorrel to a condition in which it is fitted for the growth of more valuable plants. 16. _The decay of roots_, etc., is allowed to proceed, because the preservative influence of too much water is removed. Wood, leaves, or other vegetable matter kept continually under water, will last for ages; while, if exposed to the action of the weather, as in under-drained soils, they soon decay. The presence of too much water, by excluding the oxygen of the air, prevents the _comminution of matters_ necessary to fertility. [How much heat does water take up in becoming vapor? Why does water sprinkled on a floor render it cooler? Why is not a cubic inch of vapor warmer than a cubic inch of water? Why does a wet cloth on the head make it cooler when fanned? How does this principle apply to the soil?] 17. _The evaporation of water, and the consequent abstraction of heat from the soil, is in a great measure prevented_ by draining the water out at the _bottom_ of the soil, instead of leaving it to be dried off from the surface.