The resolute tone which Preble took in this and other communications had the desired effect. In three days after the Emperor arrived he had consented to renew the treaty his father had made with the United States, and had ordered the release of all the Americans that had been seized, together with their property. At the same time the orders which had been given to capture American vessels were revoked; whereupon Preble restored the "Mirboka," and withdrew his own order to seize the vessels of Morocco. This done, he sailed for Tripoli. Already the "Philadelphia," with the schooner "Vixen" in company, had taken her station before the enemy's port, and preparations were made to maintain a strict blockade. It needed two vessels at least for this service; for if any accident happened to one alone, she would certainly be lost, being so far from help and close to the watchful guards of the enemy's harbor. Nevertheless, immediately after his arrival Captain Bainbridge heard from a Neapolitan merchantman that one of the enemy's corsairs had sailed the day before, and he sent the "Vixen" off to find her. Next day, it being the 31st of October, a Tripolitan vessel was descried to the eastward of the city, attempting to work into the harbor. Captain Bainbridge at once gave chase. The wily Tripolitan kept on his course, not far from the shore, where he knew the water was full of reefs and sunken rocks which he could easily avoid, but which he hoped might prove a trap for his unsuspecting enemy. And so it came about; for the captain, whose zeal, as we have already seen, was sometimes greater than his prudence, forgetting the dangers of the treacherous coast, followed the Tripolitan, with a fair breeze and a good eight-knot speed, until suddenly the water began to shoal. Then realizing for the first time his peril, he turned his vessel's head off shore. But it was now too late; and an instant later the "Philadelphia" had shot up on a sunken reef, where she hung hard and fast, her great stem and bowsprit pointing upward in the air. [Illustration: "HE CUT AWAY THE ANCHORS, ... BUT STILL THE SHIP HUNG FAST."] Even now the captain did not lose his confidence, and setting all sail he tried to force the vessel over; but this only had the effect of thrusting her higher on the rocks, and making escape more hopeless than ever. It was clear that this plan would not work. The boats were then sent out with leadsmen, who found deep water astern of the ship, and the yards were braced aback, and every one watched anxiously to see if she would not back off; but she did not move an inch. Then Bainbridge tried to lighten her. He cut away the anchors and threw overboard the forward guns, but still the ship hung fast.