FRIDAY.--On Friday, the 21st of August, rumours were current through the city that one, if not two ships had been wrecked during the previous night off the entrance to the harbour, and the greatest excitement prevailed in consequence; especially as the reports stated that one of the vessels was the "Vocalist," an emigrant ship with over 500 persons on board. The state of the weather for a day or two past had been such as to justify the most serious apprehensions. The day previous it had been particularly stormy, and the wind had shifted to nearly every point of the compass, having been during the fore part of the day, in the N.E. quarter, with a heavy sea from the eastward. Towards the evening it shifted to the W. and N.W., and by midnight it blew a gale at S., veering to S.E. towards the morning, with a tremendous sea setting in dead upon the land. The ship "Europa," from Bremen, which arrived in Sydney on Thursday morning, reported having been in company with a large ship for five days off this coast, and a steamer that came in the same day, also gave information of having seen a "large ship" near the land, bearing East; but neither of them could report her name. The steamer "Grafton," Captain Wiseman, from the Clarence River, while entering Port Jackson this morning (Friday), was the first who gave the alarm. Captain W. reported that he had passed, floating between the Heads, numerous pieces of ship timbers, bedding, bales of goods, and other articles, denoting a recent wreck. At about half-past seven a.m., however, Mr. Hydes, one of the pilots stationed at Watson's Bay, perceived indications of a shipwreck in the vicinity, and, in company with another pilot, Mr. Robson, whom he immediately informed of the circumstance, he at once proceeded to examine carefully the rocky coast, and at length discovered the portion of a large vessel ashore between the "Gap" and the Lighthouse; they supposed her to have been of at least 1000 tons burthen, and of American build, the fittings that could be seen being of unpainted white deal, similar to that ordinarily used in emigrant ships, the fastenings of copper, figure head a gilt scroll, masts and bowsprit hooped.