"With these rocks well wet down I wouldn't care much about having to run back to the land," muttered Harry, dryly. "However, I won't have to go back on my own feet. Tom will have the boat out here, and undoubtedly he will plan to have us both taken back to shore after we get through cruising around here. We should have brought the boat out in the first place." A night bird screamed, then flapped its wings close to Harry's face in its flight past him. The young engineer saw the moving wings for an instant; then they vanished into the black beyond. Farther out some other kind of bird screamed. The whole situation was a weird one, but Harry was no coward, though a less courageous youth would have found the situation hard on his nerves. Still another night bird screamed, of some species with which Hazelton was wholly unacquainted. The cry was answered by some sort of strange call from the shore. "It's a fine thing that I'm not superstitious," laughed the young engineer to himself, "or I'd surely feel cold chills chasing each other up and down my spine." As it was, Harry shivered slightly, though not from fear. With the increasing wind it was growing chilly out there for one who could not warm himself with exercise. "It's a long time, or it seems so," muttered the young engineer presently. "Yet I'll wager that Tom is hustling himself and others on the very jump." Again the call of a night bird, and once more a sound from shore seemed to answer it. "Real birds?" wondered Hazelton, with a start of sudden curiosity. "Or have I been listening to human signals? If so, the signals can't cover any good or honest purpose." That train of thought set him to listening more acutely than before. Yet, as no more calls reached his ears the attention of the young engineer soon began to flag. The monotonous lapping of the waves against the stone wall, the constant splashing of water over the rocks and the steady blowing of the wind all tended to make the watcher feel drowsy. "What on earth can be keeping good old Tom?" Harry wondered, more than once. It would have been well, indeed, had Harry kept his eyes turned oftener toward the shore end of the wall. In that case he might more speedily have detected the wriggling, snake-like movement of the big negro moving toward him. With great caution the huge prowler came onward, raising his head a few inches every now and then and listening. The black man's nostrils moved feverishly. He was using them, as a dog would have done, to scent any signs of alarm on the part of the human quarry that he was after. At last Harry Hazelton turned sharply, for his own ears were attuned to the stillnesses of the western forests and his hearing was unusually acute. He had just heard a sound on the wall, not far away. Instantly the young engineer was on the alert. Then his eyes, piercing the darkness, made out the crawling, dark form, which did not appear to be more than fifty feet away from him.