This delicate task was undertaken. It was necessary to avoid even a tread heavier than common, a fall of the boat-hook, or a collision with the vessel, as the slightest noise became distinctly audible in the profound stillness of deep night. Once enlightened as to his real position, however, Paul saw with his mind's eye obstructions that another might not have avoided. He knew exactly where to lay his hand, when to bear off, and when to approach nearer to the side of the ship, as he warily drew the boat along the massive hull.--The yard of the launch luckily leaned towards the reef, and offered no impediment. In this manner, then, the two gentlemen hauled their boat as far as the bows of the ship, and Paul was on the point of giving a last push, with a view to shove it to as great a distance possible ahead of the packet, when its movement was suddenly and violently arrested. Chapter XXV. And when the hours of rest Come, like a calm upon the mid-sea brine Hushing its billowy breast-- The quiet of that moment, too, is thine; It breathes of him who keeps The vast and helpless city while it sleeps. BRYANT. It was chilling to meet with this unexpected and sudden check at so critical a moment. The first impression was, that some one of the hundreds of Arabs, who were known to be near, had laid a hand on the launch; but this fear vanished on examination. No one was visible, and the side of the boat was untouched. The boat-hook could find no impediment in the water, and it was not possible that they could again be aground. Raising the boat-hook over his head, Paul soon detected the obstacle. The line used by the barbarians in their efforts to move the ship was stretched from the forecastle to the reef, and it lay against the boat's mast. It was severed with caution; but the short end slipped from the hand of Mr. Sharp, who cut the rope, and fell into the water. The noise was heard, and the watch on the deck of the ship made a rush towards her side. No time was to be lost; but Paul, who still held the outer end of the line, pulled on it vigorously, hauling the boat swiftly from the ship, and, at the same time, a little in advance. As soon as this was done, he dropped the line and seized the tiller-ropes, in order to keep the launch's head in a direction between the two dangers--the ship and the reef. This was not done without some little noise; the footfall on the roof, and the plash of the water when it received the line, were audible; and even the element washing under the bows of the boat was heard. The Arabs of the ship called to those on the reef, and the latter answered. They took the alarm, and awoke their comrades, for, knowing as they did, that the party of Captain Truck was still at liberty, they apprehended an attack.