At six hundred feet, he leveled off and sent the _Loening_ speeding in a circle around the island. The house, a one-story bungalow, built of native stone with hollow tile roof, stood on a craggy knoll near the center of the island. Bill saw that this slight eminence held unusual factors of defense. Not only was it impossible to look down on the house from any other point on the island, but the rocky ground sloped steeply on all sides from the top of the knoll. The one bad feature of the place was the number of large boulders nature had splattered up and down the incline. Behind twelve or fifteen of these big stones and completely ringing the little fortress above them, crouched the party of armed men.