The mystery increased.
The river seemed to end abruptly in a sand bank.
It was true.
All vegetation ceased; the oasis had been crossed.
The green grass was to give way to dry sand.
That did not surprise them.
They expected it, but what puzzled them was that a little stream, rising from springs at one end of the rectangular oasis, had swollen into a river, whose rippling waves showed a strong current, and when some great lake was expected, or another river, of which it might be tributary, nothing was found but sand.
“It was all a mirage,” suggested Max.
“What do you mean?”
“Why, we only imagined the river.”