It having been agreed, in a council held at the camp of St. Germaine's, as suggested in the foregoing letter, to take possession of Leghorn, not a moment was lost, by Lord Nelson, in preparing for that expedition. The King and Queen of Naples, affected by the very indifferent state of his lordship's health, and fearing that the exertion might prove too much for their chief protector, wished him to remain at Naples. When the queen, accordingly, through the medium of Lady Hamilton, advised him to send the troops; he instantly directed her to inform her majesty, that it was his custom, in order to succeed, not to say--"Go!" but--"Let us go!" Such was the dispatch used on this occasion, that all the troops were embarked, and his lordship sailed from the Bay of Naples, on the 22d instant. The Vanguard, Culloden, Minotaur, and Alliance, were the only British ships, on board of which were about two thousand seven hundred soldiers; and, in the Portuguese Principe Real, Albuquerque, and St. Sebastian, two thousand four hundred. In all, five thousand, one hundred and twenty-three. As it blew a strong gale all that night, and the following day, none but the British kept company with the Vanguard, which arrived in Leghorn Road on the 28th. The ministers of their Majesties of Great Britain and of the Two Sicilies, the Honourable William Windham and the Duke Di Sangro, immediately going on board the Vanguard, and being of opinion that a summons in the name of Admiral Lord Nelson, as well as that of the Neapolitan General Naselli, would be proper, the following was instantly prepared. "We, the commanders of the troops of the King of the Two Sicilies, and of the squadron of his Britannic Majesty, now before Leghorn, demand of the Governor of Leghorn the free and instant admission of his Sicilian Majesty's troops into the town and fortress of Leghorn, and every thing thereunto depending. If you refuse, we have power to enforce our just demand; which will, undoubtedly, instantly be done. "Naselli, General. "Nelson, Rear-Admiral." Captain Troubridge, accompanied by the two ministers, went on shore with this summons: and he returned, at eight in the evening, with a capitulation signed; in consequence of which the troops were immediately landed, and possession taken of the town and fortress of Leghorn.