The stranger began laughing.
"I accept," she said. "I recognise the Yankee in that proposition."
After this, the conversation ceased, and their entire attention was concentrated on the prairie. The most profound calm still continued to brood over the desert; apparently, all was in the same state as at sunset. Still the stranger's piercing eyes distinguished on the river bank several wild beasts flying precipitately, and others escaping across the river, instead of continuing to drink. One of the truest axioms in the desert is:—there can be no effect without a cause. Everything has a reason in the prairie, all is analysed or commented on; a leaf does not fall from a tree, a bird fly away, without the observer knowing or guessing why it has happened.
After a few moments of profound examination, the stranger seized the emigrant's arm, and bending down to his ear, said in a weak voice, like the sighing of the breeze, one word which made him tremble, as she stretched out her arm in the direction of the plain.
"Look!"
Black bent forward.
"Oh!" he said a minute after, "what is the meaning of this?"
The prairie, as we have already mentioned, was covered in several places by blocks of granite and dead trees; singularly enough, these black dots, at first a considerable distance from the camp, seemed approaching insensibly, and now were only a short way from it. As it was physically impossible for rocks and trees to move of their own accord, there must be a cause for this, which the worthy emigrant, whose mind was anything but subtle, cudgelled his brains in vain to guess. This new Birnam Wood, which moved all alone, made him excessively uncomfortable; his son and servants had also noticed the same fact, though equally unable to account for it. Black remarked specially that a tree he remembered perfectly well seeing that same evening more than one hundred and fifty feet from the mound, had suddenly come so close, that it was hardly thirty paces off. The stranger, without evincing any emotion, whispered—
"They are the Indians!"
"The Indians?" he said, "impossible!"