Over a great part of the West, water power is very abundant and the suggestion has been made that the electric energy which can be developed by means of water power could be used in the cultural operations of the dry-farm. With the development of the trolley car which does not run on rails it would not seem impossible that in favorable localities electricity could be made to serve the farmer in the mechanical tillage of the dry-farm. The substitution of steam and other energy for horse power is yet in the future. Undoubtedly, it will come, but only as improvements are made in the machines. There is here also a great field for being of high service to the farmers who are attempting to reclaim the great deserts of the world. As stated at the beginning of this chapter, dry-farming would probably have been an impossibilityfifty or a hundred years ago because of the absence of suitable machinery. The future of dry-farming rests almost wholly, so far as its profits are concerned, upon the development of new and more suitable machinery for the tillage of the soil in accordance with the established principles of dry-farming. Finally, the recommendations made by Merrill may here be inserted. A dry-farmer for best work should be supplied with the following implements in addition to the necessary wagons and hand tools:-- One Plow. One Disk. One Smoothing Harrow. One Drill Seeder. One Harvester or Header. One Mowing Machine. CHAPTER XVI IRRIGATION AND DRY-FARMING Irrigation-farming and dry-farming are both systems of agriculture devised for the reclamation of countries that ordinarily receive an annual rainfall of twenty inches or less. Irrigation-farming cannot of itself reclaim the arid regions of the world, for the available water supply of arid countries when it shall have been conserved in the best possible way cannot be made to irrigate more than one fifth of the thirsty land. This means that under the highest possible development of irrigation, at least in the United States, there will be five or six acres of unirrigated or dry-farm land for every acre of irrigated land. Irrigation development cannot possibly, therefore, render the dry-farm movement valueless. On the other hand, dry-farming is furthered by the development of irrigation farming, for both these systems of agriculture are characterized by advantages that make irrigation and dry-farming supplementary to each other in the successful development of any arid region.