His Majesty's ship, Thetis, Captain Samuel Burgess, sailed from Rio Janeiro on the evening of the 4th of December, 1830, having a large amount of treasure on board. The weather was so thick, that as they worked out of the harbour, the islands at its entrance were not visible; but as the evening was tolerably fine, with the exception of the fog, Captain Burgess determined to persevere in his course. The following morning the fog dispersed, but it was soon succeeded by such heavy rain, that the obscurity was nearly as great as before. The ship continued her course with the wind upon the starboard tack, until half-past one in the afternoon, when, from the reckoning, they supposed Cape Frio to be about thirty-eight miles distant, lying north 36 deg. east. From the hour of their departure from Rio Janeiro, till the time of which we speak, neither sun, moon, nor stars had been visible. On account of the cross sea, which appeared to impede the progress of the vessel, and the lightness of the wind, her course was kept east by north until two o'clock, when it was changed to E.N.E. At four o'clock P.M. it was calculated that they had run about nineteen miles, and that they must be nearly abreast of Cape Frio, and about twenty-four miles distant from it. The weather clearing up at that time, they discovered a large ship, with all sail set, standing in shore, and no land being visible, they concluded that they were still further from land than they had reckoned, and therefore they changed their course again to N.E. by E. At five o'clock the people were mustered at quarters, and then a looming of land was seen to the N.N.W., which, according to their calculation, was the direction Cape Frio would bear; and there being no land near it that could have the same appearance, the reckoning was considered correct, and a prudent proportion of sail was made, regard being had to the state of the weather, and the course they were steering. Between six and seven o'clock P.M. the rain again began to fall; the fog returned, and became gradually so thick, that it was impossible to see the length of the ship. At eight P.M. the watch was mustered, and the men placed at their stations to keep a vigilant look-out, while the officer of the watch went forward himself to see that the sails were well trimmed, and that every one was on the alert. At half-past eight, when the captain had retired to his cabin, and was waiting for the usual evening report from the master, a midshipman entered with the startling intelligence that land had been seen close ahead, the ship at the time going at the rate of eight or nine miles an hour.