In the meantime the land in the valley below had been growing more fertile, for each year the spring floods had left a rich soil deposit behind them. The farmer down there had been innocently stealing the land above him, but not all of it, for much had been carried out to sea. It is not possible to prevent this entirely, but much of the loss might have been avoided by leaving the hilltops, which are never well fitted for cultivation, covered with forests. In this way the soil-wash from above is prevented and the streams run gently and with only a small amount of muddy deposit, forming proper drainage for the soil. The preserving of the forests on the great mountain ranges of the country, where nature has placed them, will mean in the one matter of soil-wash, fruitful lands and bountiful harvests, instead of barren, wasted lands, desolated by floods and seamed by great ravines, carrying desolation to the lands below them. But in many cases the trees are already cut away. Here replanting becomes necessary and should be done in every case where soil-wash is beginning on the mountain tops. It is almost equally desirable to plant small shrubs and bushes as an undergrowth, so that the roots may form a thick mat below the ground to hold the water in the soil, and permit it to filter through slowly. In Massachusetts, the tracks of the Boston and Albany Railroad are depressed so that trains may pass below the level of the highways. In order to protect the banks from erosion, the sloping sides of this roadway have been planted with trailing rose-bushes and other vines which have thickly matted roots. These serve a double purpose in preventing landslides and washouts on the tracks, and in adding greatly to the attractiveness of the scenery along the railway. The poorest land of a farm is always found on the hilltops, because even with the greatest care there is always considerable waste of the top-soil. This land, then, should never be used for field crops. It should constitute the woodland, or if this is not possible, the pasture-land of the farm, for the grass roots protect the soil and prevent it from washing away, and the profits on the hay are at least as great as any other crop which could be grown on hill land. But when erosion has been checked and the top-soil preserved, when the soil is thoroughly fertilized, and a proper rotation of crops established, there are still other lessons to be learned in order to make our country as productive as it might be, as it will _need_ to be to support the population that we shall have by the end of the century. As a nation we undertake to farm too much land and do it carelessly. The invention of labor-saving machinery has made it possible to farm hundreds and even thousands of acres together with little physical labor. This has made farmers heedless of small amounts of land wasted.