Twice over, as the diagonal ascent grew steeper, the blacks halted for about half-an-hour, and the prisoners were glad to lie down in the shelter of one of the lava blocks with which the slope was strewn, the cool air which came from the sea being fresh and invigorating; and the second time Ned suddenly exclaimed-- "Not going to take us up to the top, are they, and pitch us into the fire?" "Not likely, Ned," replied Jack; "but we little expected to make the ascent like this." "With our hands tied behind us, sir." "I believe they are going this way so as to avoid the forest, and as soon as we get a little farther round they will begin to descend on the other side." Jack's idea proved to be correct, for upon reaching a spot where nothing but a friable slope of fine ashes kept them from the summit, the leader suddenly leaped down into a hollow which was scored into the mountain side, and began to descend, followed by the rest. "Due west," said Jack thoughtfully. "Why, Ned, we shall reach the shore far from where we left the yacht." "If it goes straight down, sir; but is it west?" "Yes, we are going straight for the sun now, and this gash in the mountain grows deeper. Look." "Yes, that's right, sir; but I do wish we could get to some water now. It's a dry journey from here to the shore, and you're beginning to be done up." "Yes, Ned," said Jack wearily; "I am beginning to be done up now." CHAPTER THIRTY SIX. RUNNING THE REEF. The whole of that journey down the rugged gash in the mountain side was a prolonged agony to Jack, but he fought like a hero to keep his feet, and at last, satisfied that he could not escape, the man who had surprised him and treated him as his own prize caught him by the shoulder as he was tottering down the descent, with the stones every here and there giving way beneath his feet, and about to fall heavily. The next minute his numbed and swollen hands were set at liberty, so that he could better preserve his balance, and the first use he made of them was to point to Ned's bonds, with the result that the man's captor entered into a short colloquy with Jack's; and the savage fitted an arrow to his bow and took aim, half drawing the arrow to the head, while he jabbered away and scowled menacingly, showing his white teeth the while. "What does he mean by that, Mr Jack? going to shoot me--a coward?" "No, no; he means he will untie your hands, but that if you attempt to escape an arrow will go faster than you can run, and he will bring you down." "And very kind of him too, sir. But I shan't run away without you, sir. Here, undo 'em then, blackie." He bent forward so as to raise his tied hands, and the black began to unfasten the cane.