“Water? No; only a peculiar effect seen in the atmosphere over a heated plain. We shall see no water till we near the mountains on the other side. But there, talk as little as you can, and avoid this heated dust which rises from the mules’ hoofs.”
“It’s wonderful!” cried Ned thoughtfully. “I felt sure that we were near a beautiful lake.”
“Such as deceives travellers sometimes.”
“Ah, it’s bad,” said Griggs, “when you’re crossing a plain, choking with thirst, and the water-bottles are empty. A sight like that has driven men mad before now with disappointment.”
The boys recalled these words over and over again during their journey, for from the very first they realised what a tramp through such a desert meant—the sun came down with scorching power, and it was reflected up from the white sand and salt. At mid-day when they halted where there was no shadow but that cast by their four-footed companions, there was not a breath of air, and the poor brutes stood with hanging heads and drooping ears, panting and even sighing, while when the evening drew near the wind swept boisterously over the plain, but brought no refreshment, for not only was it hot, but it wafted up the fine, irritating dust and produced additional sensations of thirst.
The march was kept on long after sundown, when another halt was made for refreshment; but there seemed to be none, for the amount of water used was small in the extreme, and after about an hour’s wait, during which the baggage animals had been relieved of their burdens, the doctor rose.
“Now then,” he said sternly, “load up. We must keep on all through the night, and refresh again at daybreak.”
“Refresh!” said Wilton dismally.
“Well, rest the mules,” replied the doctor. “Then go on again for three or four hours and try and sleep through the hottest part of the day.”
“What about keeping our course correctly through the night?” said Bourne.