want of water and of wood. More than once we had no other fuel than the dry bison-dung, and three times at our camping ground water failed us. This is a hard trial for man and horse, especially after traveling all day under the burning sun of the month of August. Another kind of torment, still less supportable when the heat is most intense, is the appearance of fantastical rivers and lakes in the verge of the horizon, seeming to invite the weary traveler to advance and refresh his wasted strength upon their banks. Fatigue and thirst picture in the distance verdure, shade and coolness awaiting him. The illusion increases the desire of quenching your burning thirst. You hasten onward to reach the goal. Hour succeeds hour; the deceitful mirage heightens in brilliancy, and the panting, exhausted traveler presses on without a suspicion that the phantom flies before him. In an open, elevated region, where the atmosphere is in continual agitation, this effect may be easily produced by the reverberation of the sun's rays from the surface of these vast prairies, throwing the various tints of the verdure upon the deep blue of the firmament.
Besides the difficulties arising from the nature of the ground, there are others which summer always brings with its myriads of insects. Among these, the most to be dreaded is the gad-fly, the sting of which will make the gentlest horse bound with rage. Happily for the horse in these plains, Providence has bestowed upon him a defender as skilful as devoted; the starling, unalarmed by the presence of man, which, wheeling ever about the rider, lights on the back of the horse or on his load, to dart with wonderful skill upon the malicious insect which is about to attack his traveling companion.
For ourselves, we were obliged to wage continual war upon the swarms of mosquitoes and their allies the gnats. The latter teased us by day, the former, more cowardly, attacked us by night. These famished enemies, the product of the stagnant waters and decaying plants, at the approach of a convoy rush from their infected abodes, and accom