I found that I had several erroneous notions of my own to correct. I always fancied that a porpoise was a great fat lumbering sleepy animal, simply because people are accustomed to say "as fat as a porpoise." In reality he is a gracefully formed, remarkably fast, sociable, warm-hearted, or rather warm-blooded fellow, with a coat of fat like a paletot on his back, to keep out the chill of the icy seas. He is more like a hunter than a pig; and, as to "rolling and wallowing," those are expressions used by poets who never saw a porpoise dashing away at twenty or thirty knots an hour, or a whole shoal bearing down upon a ship like a troop of light horse, and escorting her for miles and miles, careering away, darting round and round her as if she were only going at the speed of some heavy baggage waggon; and humbling the pride of those who have been before hugging themselves with the pleasing idea that she has been moving along at a tremendous speed. The back fin is triangular and near the tail; and as the active fish plunges forward through the tumbling seas, the fin seen for an instant, and looking like his back, makes him appear as if he was rolling slowly on in the water--a very different movement from what he really makes, which is rapid in the extreme. While talking of cetaceous animals, to which order the porpoise belongs, I must remark on a very common error held by seaman as well as landsmen, that whales spout out water. The idea is, that the water is taken into the stomach while the whale is feeding, and ejected when he rises to the surface. This is in no sense the case. What the whale spouts forth is a steam-like air, dense with mucous vapour, of which he must empty his lungs before he can take in a fresh supply of atmospheric air to enable him to dive down again to the depths of the ocean. We were now enjoying the north-east trade wind. The latitude in which these winds are to be met with varies by several degrees, according to the season of the year. An indication that we were entering them was shown by the barometer, which had previously been low, falling still more from 30 degrees 3 minutes to 30 degrees 2 minutes, and even lower. But if I was to go on describing all the phenomena I observed, and all the information on natural history I obtained, I should have no space left for my own adventures, or an account of the countries I visited. I spoke of Mr Vernon, a clergyman. At first he had been ill, but when he recovered he made a great effort to have religious services held on board on each Sunday, as well as on other days of the week. The captain and first mate, as may be supposed, objected to the measure. "People might go to church when they got on shore if they liked, but on board his ship he was not going to have anything of that sort," was the captain's reply.