It is true that in the Southern States there are some millions of acres, chiefly timber lands, which at no remote time will be occupied for agricultural purposes. Westward toward the Great Plains, the lands in what I have, in the body of this volume, termed the Humid Region have passed from the hands of the General Government. To this statement there are some small exceptions here and there--fractional tracts, which, for special reasons, have not been considered desirable by persons in search of lands for purposes of investment or occupation. In the Sub-humid Region settlements are rapidly extending westward to the verge of the country where agriculture is possible without irrigation. In the Humid Region of the Columbia the agricultural lands are largely covered by great forests, and for this reason settlements will progress slowly, as the lands must be cleared of their timber. The redemption of the Arid Region involves engineering problems requiring for their solution the greatest skill. In the present volume only these lands are considered. Had I been able to execute the original plan to my satisfaction, I should have treated of the coast swamps of the South Atlantic and the Gulf slopes, the Everglade lands of the Floridian Peninsula, the flood plain lands of the great rivers of the south, which have heretofore been made available only to a limited extent by a system of levees, and the lake swamp lands found about the headwaters of the Mississippi and the region of the upper Great Lakes. All of these lands require either drainage or protection from overflow, and the engineering problems involved are of diverse nature. These lands are to be redeemed from excessive humidity, while the former are to be redeemed from excessive aridity. When the excessively humid lands are redeemed, their fertility is almost inexhaustible, and the agricultural capacity of the United States will eventually be largely increased by the rescue of these lands from their present valueless condition. In like manner, on the other hand, the arid lands, so far as they can be redeemed by irrigation, will perennially yield bountiful crops, as the means for their redemption involves their constant fertilization.