At noon the latitude was observed to be 32 degrees 30 minutes 42 seconds, but by the land it was only 32 degrees 23 minutes 30 seconds, a difference of 7 minutes 12 seconds. This error was occasioned by the haze which concealed the true horizon, and caused an appearance of land all round us, on which rocks, sandy beaches, and trees were so plainly formed that the officer of the watch actually reported two islands on the western horizon. This was the most remarkable instance of mirage that we ever witnessed; the haze had only commenced a few minutes before noon, whilst the observation for the latitude was in the act of being taken; and immediately after I was employed upon the chart for half an hour, puzzling myself in attempting to reconcile the observed latitude with the bearings of the land. This curious phenomenon was also witnessed by the French in Geographe Bay. During the time this magical appearance continued, we had very light airs from the southward: the barometrical column fell to 29.76 inches, but the hygrometer indicated an extraordinary dryness of the air. At sunset the haze cleared away, when Rottnest Island was seen, bearing between North 10 degrees and 32 degrees East (magnetic); a breeze then freshened from West-South-West but gradually veered round to the southward; and at nine o'clock was very light from South-East. January 13. During the night we made short tacks. At four o'clock in the morning (13th) the latitude by the moon's meridional altitude was 32 degrees 16 minutes 17 seconds, and soon afterwards Rottnest was in sight in the North-North-East. At six o'clock the sky was clouded, and the weather threatened to be bad; the mercury fell to 29.69 inches, upon which all sail was made off the land, as appearances indicated a westerly gale: but after an interval of two hours, during which we had a fresh breeze from North-West by West, the weather cleared up and we steered towards Rottnest Island. January 14.