It took time for Smith to regain his balance. When he did, the same unbroken expanse of sky once more met his gaze; but it was not long until, out of the corners of those unblinking eyes, he could make out bleary forms which shortly resolved themselves into mountain tops. It was odd, the way things suddenly flashed into full view. One second they would be blurred and unrecognizable; the next, sharply outlined and distinct as anything the engineer had ever seen. Yet, there seemed to be no change in the focus of those eyes. It wasn't as though they were telescopic, either. Not until long afterward did Smith understand the meaning of this. The mountains grew higher and nearer. Before long it seemed as though the aircraft was entering some sort of a canon. Its sides were only sparsely covered with vegetation, and all of it was quite brown, as though the season were autumn. For the most part the surface was of broken rock and boulders. Within a space of three or four minutes the engineer counted not less than ten buzzards. The unknown operator of the machine, however, paid no attention to them, but continued his extraordinary watch of the heavens. Smith began to wonder if the chap were not seated in an air-tight, sound-proof chamber, deep in the hull of some great aerial cruiser, with his eyes glued fast to a periscope. "Maybe a sky patrol," thought the man of the earth; "a cop on the lookout for aerial smugglers, like as not." And then came another of those terrifying stops. This time, as soon as he could collect his senses, the engineer saw that the machine had landed approximately in the middle of the canon, and presumably among the boulders in its bottom. For all about it were the tops of gigantic rocks, most of them worn smooth from water action. And, as soon as the engine stopped, Smith plainly heard the roar of water right at hand. He could not see it, however. Why in the name of wonder didn't the fellow look down, for a change? The craft began to move. This time its motion was smoother arguing an even surface. However, it had not gone far before, to the engineer's astonishment, it began to move straight down a slope so steep that no mechanism with which Smith was familiar could possibly have clung to it. As this happened, his adopted eyes told him that the craft was located upon one of those enormous boulders, in the center of a stream of such absolute immensity that he fairly gasped. The thing was--colossal! And yet it was true. The unseen machine deliberately moved along until it was actually clinging, not to the top, but to the side of the rock. The water appeared to be about five yards beneath, to the right. To the left was the sky, while the center of that strange vision was now upon a similar boulder seemingly a quarter of a mile distant, farther out in the stream. But the fellow at the periscope didn't change position one whit!