perienced the influence of an opposite current of air, of a different hygrometric and thermometric condition; facts which tend in some degree to explain the means by which the equilibrium of the atmosphere under certain conditions is maintained in those regions. Count Strzelecki further informed me of the following seemingly anomalous circumstance,—that at the height of 6,000 feet he found the current of air blowing at right angles to both the lower strata, also of a different hygrometric and thermometric condition, but warmer than the interstratum.
Our approach to St. Paul's Rocks, for which we were steering, was indicated by the appearance of the sea-birds which inhabit them, and at nine the next morning their two higher points were seen like specks on the horizon, at a distance of three or four leagues: the lower and smaller rocks gradually rose into view on nearing them, but our ships having been carried during the night so far to leeward, by a strong westerly current which we found to prevail here, we could not fetch them until late in the evening.
Nov. 29.We landed early the next morning, but not without difficulty, owing to the surf and swell which broke through the several channels into the central basin. We found the steep north-eastern side of the cove the most practicable point, and near it we obtained our observations. These remarkable rocks, which lie in lat. 0° 56′ N. and long. 29° 20′ W., and more than five hun-
