It may be said that the population of those parts of Oregon, Washington, Idaho, Wyoming, and Montana, which are embraced in the watershed of the Columbia, is probably nearly a million and a quarter. The population of the area in British Columbia is scanty, but rapidly increasing. The productive capacity is very great. A rough estimate of production in the valley of the Columbia for the year 1908 would probably give a grain production of seventy million bushels, a lumber output of three billion feet, a mineral output worth sixty million dollars, and a combined output of pastoral, horticultural, fishing, and miscellaneous industries of fifty millions of dollars. Such figures indicate that the Columbia River is already a factor in world commerce. Yet its development is but begun. What is to be its part in the world commerce of the future? Inspection of a map will show that the Columbia possesses the only water-level route from the vast productive regions of the Inland Empire to the seaboard. As has been shown in the course of this volume, the River is navigable throughout the larger part of its course from Revelstoke in British Columbia to the ocean. In that distance there is one canal, with locks. That is at the Cascades, sixty-five miles from Portland. Before the River can be continuously navigable it will be necessary that a canal be constructed to overcome the obstructions at the Dalles, a few miles above the city of that name, another at Priest Rapids, seventy miles above Pasco, and still another at Kettle Falls. The Government is already engaged in the first of these works. The second seems comparatively near of accomplishment by reason of work done and projected by a powerful irrigation company. Nothing has yet been done at Kettle Falls, but it would be comparatively a light task to provide canal and locks at that point. Besides these larger obstructions there are several rapids at points between Kettle Falls and the Dalles which impede navigation at certain stages of water. The Government has made surveys of these sections of the River, and has announced that with comparatively small outlay the rocks and reefs may be removed, the channels deepened and straightened, and the River made navigable. One thing may be emphasised in this connection, and this is that the Columbia River has mainly a rocky bed, and hence work on the channels is permanent. It will not cut and fill, nor pile up islands and bars as does the Missouri. In view of the capability of the River to carry great water traffic, and in view of the fact that railroad traffic is seeking and will still more seek the down-hill grade to the sea, it becomes a question of great interest what the future commerce of the River will be.