A gale of wind prevented the American vessels from commencing operations before the 3d of August. On that day Com. Preble stood in within a league of Tripoli, with a pleasant breeze from the eastward. Here he wore ship, with his head off the land, and signaled all the vessels to pass within hail of the Constitution. As the brigs and schooners passed the frigate each commander was ordered to prepare for an attack. Every thing was previously arranged, and the ardor of the young men under the orders of Preble being of the highest character, in one hour every man and craft were ready for the contemplated service. The harbor of Tripoli lies in a shallow indentation of the coast, being tolerably protected against easterly and westerly gales by the formation of the land, while a reef of rocks, which stretches for a mile and a half in a northeasterly course, commencing at the town itself, breaks the seas that roll in from the northward. This reef extends near half a mile from the walls, entirely above water, and is of sufficient height and width to receive water batteries, containing the Lazaretto and one or two forts. It is this commencement of the reef which constitutes what is usually termed the mole, and behind it lies the harbor proper. At its termination is a narrow opening in the reef which is called the western entrance, through which it is possible for a ship to pass, though the channel is not more than two hundred feet in width. Beyond this passage the rocks reappear, with intervals between them, though lying on shoals with from one and a half to five and a half feet of water. The line of rocks and shoals extends more than a mile outside of the western entrance. Beyond its termination is the principal entrance to Tripoli, which is of sufficient width though not altogether free from shoals. The distance across the bay, from the northeastern extremity of the rocks to what is called the English fort, on the main land, is about two thousand yards, or quite within the effective range of heavy guns. In the bottom of the bay, or at the southeastern angle of the town, stands the bashaw’s castle, a work of some size and force. It lies rather more than half a mile from the western entrance, and somewhat more than a mile from the outer extremity of the reef. Thus any thing within the rocks is commanded by all the water defences of the place, while shot from the castle, and more especially from the natural mole, would reach a considerable distance into the offing. Some artificial works aided in rendering the northwestern corner of the harbor still more secure, and this place is usually called the galley mole. Near this is the ordinary landing, and it is the spot that may properly be termed the port.