The first part of the night we had the wind at North-North-East, the breeze steady, and the water as smooth as glass; but as the watch wore on, quick flashes of forked lightning, and the suspicious appearance of gathering clouds in the South-East, gave warning of the unwelcome approach of a heavy squall. HEAVY SQUALL. At eleven we lay becalmed for ten minutes between two contending winds; that from the South, however, presently prevailed, and shifting to the South-East, blew hard: meantime, a dark mass of clouds in the East-South-East appeared suddenly to assume the form of a deep-caverned archway, and moved rapidly towards us; in a few minutes, the ship was heeling majestically to the passing gust, the lightning flashed vividly and rapidly around us, alternately concealing and revealing the troubled surface of the foam-covered sea, while the thunder rolled heavily over our heads. The squall was heavy while it lasted, commencing at East-South-East and ending at East-North-East. It was accompanied by heavy rain. Towards the end of the middle watch, the weather began to assume a more settled appearance, and we had a moderate breeze from the north; but between five and six o'clock A.M., it shifted suddenly by the West to South-South-East, and became light. We sounded repeatedly during the night in from 32 to 35 fathoms, the same kind of bottom as before; which we found agree very well with those reported in the account of the French expedition under Captain Baudin. From the specimens of the squalls we experienced the last two nights, and which appear to be pretty regular in their visitation, I am inclined to believe they do not extend any considerable distance from the land. They give the seaman ample warning of their approach; yet, since they always come on in the night, when their violence cannot be properly estimated, the ship's head should (if circumstances permit) be kept to the westward (West-North-West) until the short-lived fury of the storm has exhausted itself. January 15. We progressed with light and variable airs through the day, gradually shoaling our water till nine P.M., when the anchor was dropped in 14 fathoms, having previously passed over a rocky ledge of apparently coral formation, in 13 1/2 fathoms. The land over the south point of Roebuck Bay bore East-South-East, about 17 miles distant; but we did not see it till the following morning. DRIVEN FROM THE ANCHORAGE.