He nodded as he spoke, and put the flask to his lips, while the guide, who made no rejoinder, eyed him with a grave, stern expression of countenance.

That night they all encamped under the shade of a small clump of trees, kindled several large fires, and, heartily glad to be relieved of their back-burdens, sat down to enjoy supper. After it was over pipes were smoked and stories told, until it was time to retire to rest. Then each man lay down under his blanket, the sky being his canopy, and the howling of the wolves his lullaby.

It seemed to each sleeper, when awakened next morning, that he had only just closed his eyes, so sound had been his repose, and there was a great deal of violent yawning, stretching, grumbling, and winking before the whole party was finally aroused and ready to set forth. However, they got under way at last, and early in the forenoon came to the edge of a sandy plain, which appeared to be interminable, with scarcely a blade of grass on it. Here they halted for a few minutes.

“How wide is the plain, guide?” inquired Frank.

“Forty miles,” replied the man, “and there’s not a drop of water to be had till the end of the first twenty. We’ll get there about sundown, and replenish our kegs, if it’s not all gone dry. Let me warn you, however, to use the water you have sparingly.”

“Do we encamp at the end o’ the first twenty?” asked Jeffson.

“Yes, you’ll find it a long enough day’s march.”

No one made any reply, but by their looks they appeared to think nothing of a twenty-mile walk. They found, however, that such a distance, traversed over loose sand ankle-deep, and under a burning sun, was not what any of them had been accustomed to.

On entering the plain they observed that the heat had opened cracks and fissures in the earth, which omitted a fiery heat. At intervals pyramids of sand arose, which were borne with great velocity through the air, sometimes appearing in the shape of columns sixty feet high, which moved majestically over the plain. Ere long some of these clouds of sand enveloped them, and they were accompanied by hot winds, which seemed to shrivel up, not only the skin, but the very vitals of the travellers. The pores of their skin closed, producing feverish heat in the blood and terrible thirst, while their eyes became inflamed by the dazzling glare of the sun on the white sand.

Of course most of the party applied pretty frequently to their water-kegs and bottles. Even Bradling gave up his brandy, and was content to refresh himself with the little of the pure element which chanced to remain in his formerly despised, but now cherished, water-bottle. The guides carried skins of water for themselves and the mules, but these they opened very seldom, knowing full well the torments that would ensue if they should run short before getting across the scorching desert.