The thought of the _Mirabelle_ brought Chris's mission on the pirate ship into sharper focus. He glanced up at the sky; there was little time left in which to work safely, for Claggett Chew's sharp eyes had noticed the infinitesimal scar on his cheek and his astute brain had put two and two together. Chris wondered, with a new start of horror, if Claggett Chew could read his thoughts, and if this was why he had stared at him with such intensity. Well, he shrugged, he knew what had to be done and if he worked quickly, and Claggett Chew's swoon lasted long enough, not even he could stop him. Looking about to make sure he was unobserved, he took his own shape again with a sigh of relief. It was almost like holding one's breath for long periods of time, to be in the shape of a bird or a mouse, but to be himself, he knew, held even greater dangers. For the first time he opened the leather bag at his neck and felt inside. The first thing his fingers closed on he pulled out. He turned the object in his palm toward the starlight to see what it might be. It was a folding knife in a case of tortoise shell inlaid with strange signs in silver and mother-of-pearl. Chris opened it--the blade was razor-sharp--and put it experimentally point down on the wood of the deck. As if by itself the blade revolved with immense speed, sinking in so fast that only just in time did Chris snatch it out and hold it more tightly. Trying it out he found that the blade would go through anything, sometimes so easily as to scarcely seem to cut, leaving no trace of a mark, it was so keen. At other times when he pressed on it, the blade whirled around, boring a hole as deep as might be necessary. What a useful gadget! Chris thought. This is just what I need and now is the time! he said to himself, and sprang up the nearest of the _Vulture's_ three masts. What he had to do would take long, and there was little time left that night in which to do it. For he intended slitting the lines of the rigging here and there, not so deeply that they would give way at once and be soon repaired, but so that with the first hard blow the lines would break. Growing daylight should have warned him long before he was done, for Chris wished also to slit the sails, very slightly, when they had been unfurled and the _Vulture_ was under way. The sound of voices broke his absorption in his task. Looking down from the top of the mainmast where he clung, Chris saw a boatload of returning sailors and realized with a start that it was nearly sunup. In a moment a rat ran down the mast to disappear into the foul-smelling hold of the pirate vessel.