As these uneasy thoughts thronged, a faint sound borne by the wind caused him to turn his head with a nervous start, and he saw something moving in the deeper darkness that surrounded the swamp. He pulled up the pony, tightening his grip on the rifle, and strained his eyes, trying to make out what this moving object was. The wavering mists were very thick, and he thought at first that it might be nothing worse than a denser gathering of the deadly vapor creeping out of the swamp. The fog suddenly fell like a heavy curtain, and he could see nothing. And then lifting again, it gave him a fleeting glimpse of a body of horsemen riding rapidly in the edge of the forest, as if seeking the shadow of the trees. He could see only the black outline of the swiftly moving shapes, but he knew that they must be part of the band which was filling the whole country with terror, violence, and death. None other could be riding at night toward Duff's Fort. He thought of the money in his pocket, and felt the thumping of his heart as his hand involuntarily went up to touch it, making sure that it was still safe. He sat motionless--scarcely daring to breathe--watching the shadows till he suddenly realized with a breath of relief that they were going the other way, in the opposite direction from his own road. And then after waiting and watching a little longer, in order to make sure that they were out of sight, he rode on. The courage and calmness which he had found in himself under this test, heartened him and made him the more determined to control his wandering fancy. Looking now neither to the right nor the left, he pressed on through the clearing toward the buffalo track in the border of the forest which would lead him into the Wilderness Road. Sternly setting his thoughts on the errand that was taking him to the salt-works, he began to think of the place in which they were situated, and to wonder why so bare, so brown, and so desolate a spot should have been called Green Lick. There was no greenness about it, and not the slightest sign that there ever had been any verdure, although it still lay in the very heart of an almost tropical forest. It must surely have been as it was now since time immemorial. Myriads of wild beasts coming and going through numberless centuries to drink the salt water, had trodden the earth around it as hard as iron, and had worn it down far below the surface of the surrounding country. The boy had seen it often, but always by daylight, and never alone, so that he noted many things now which he had not observed before. The huge bison must have gone over that well-beaten track one by one, to judge by its narrowness. He could see it dimly, running into the clearing like a black line beginning far off between the bordering trees; but as he looked, the darkness deepened, the mists thickened, and a look of unreality came over familiar objects. And then through the wavering gloom there suddenly