Water, next to wood, is the great want of the plains and of the Great Basin. Travel along either base of the Rocky Mountains, and you are constantly meeting joyous, bounding streams, flowing rapidly forth from each ravine and coursing to the arid plain; but follow them a few miles and they begin to diminish in volume, and, unless intercepted by a copious river, often dwindle to nothing. The Republican fork of the Kansas or Kaw River, after a course of some thirty to fifty miles, sinks suddenly into its bed, which thence for twenty miles exhibits nothing but a waste of yellow sand. Of course there are seasons when this bed is covered with water throughout; but I describe what I saw early in June, when a teamster dug eight feet into that sand without finding a drop of the coveted liquid for his thirst-maddened oxen. Two months later, I observed the dry bed stretched several miles farther up and down what in winter is the river. Passing over to Big Sandy, the most northerly tributary of the Arkansas, I found dry sand (often incrusted with some white alkaline deposit) the rule; water the rare exception throughout the twenty or thirty miles of its course nearest its source. At Denver, on the 6th of June, Cherry Creek contributed to the South Platte a volume amply sufficient to run an ordinary grist-mill; ten days afterwards its bed was dry as a doctrinal sermon. My first encampment on the North Platte above Laramie was by a sparkling, dancing stream a yard wide, which could hardly have been forced through a nine-inch ring; but though its current was rapid and the Platte but three miles off, the thirsty earth and air drank up every drop by the way. Big Sandy, Little Sandy and _Dry_ Sandy are the three tributaries to be crossed between South Pass and the Colorado, and the latter justifies its name through the better part of each year. Golden River runs through too deep a narrow valley and bears too strong a current from the snowy peaks in which it heads to be thus dried up; so with Bear, Welso, and the Timpanagos or Jordan, the principal affluents of Salt Lake, which tumble and roar between lofty peaks the greater part of their respective courses; but when you have crossed the Jordan, moving California-ward, you will not find another decent mill-stream for the five hundred miles that you traverse on your direct (Simpson's) route to the sink of the Carson. At intervals which seem very long, you find a spring, a scanty but welcome stream rushing down between two mountains, to be speedily drunk up by the thirsty plain and valley at their base; but you will oftener pass some 'sink' or depression below the general level of the valley you are traversing, where a shrewd guess has led to brackish or sulphurous water by digging two or three feet. A mail station-keeper lost his oxen, at a point a hundred miles south-west of Salt Lake; they had wandered southward on the desert, and he followed their trail for (as he estimated) a hundred miles, without finding a drop of water, when he gave them up, still a day's tramp ahead of him, and turned back to save his own life and that of his suffering horse. He might, I presume, have gone a hundred miles further without finding aught to drink but their blood.