He had not got more than half through it, when a low drowsy whinny made reply from the depths of the darkness before him, and the heart of Richard leaped in his bosom for joy.

He ceased a moment, then whistled again.

Again came the response, but this time, although still soft and low, free from all the woolliness of sleep.

Once more he whistled, and once more came the answer.

Certain at length of the direction, he dropped on his hands and knees, and crawled carefully along for a few yards, then stopped, whistled again, and listened.