This they do by closing a valve leading to the nasal passages, and forcing it by means of air through the blow-hole placed in the upper part of the head. It is this necessity of whales for breathing at the surface which enables man to make them his prey, in spite of their immense strength, while their spouts point out to him the place where they are to be found. The remarks I have made apply in common to the two chief sorts of whales, but the Greenland whale is a very different animal from the sperm whale, of which we were in search. The Greenland whale, (_Balaena mysticetus_), is also called the common, true, or whale-bone whale. I remember once, in a man-of-war, falling in with a dead whale in a perfect calm. We towed it alongside, but so ignorant was everybody on board of natural history, that no one knew where the whale-bone was to be found. At the cost of great trouble, with a horrible odour to our noses, we cut out a jaw-bone; which was perfectly valueless, except to make the front of a summer-house for our commander; and we then let our prize go with its rich contents, and glad enough we were to get rid of it. The Greenland whale is less in size than the sperm--its length being about 60 feet. The head occupies about a third of the entire length. It is narrow above, and broad, flat, and rounded beneath, so as to allow it to move rapidly under the water. The body is largest about the middle, and tapers suddenly towards the tail. The general colour is a blackish-grey, with part of the lower jaw, and throat, and belly white. The lips are five or six feet high, the eyes very small, and the external opening of the ears scarcely perceptible. The pectoral fins or arms are not long, and are placed about two feet behind the angle of the lips. The black whale has no teeth; but from the upper palate and jaw there hang down perpendicularly numerous parallel laminae--the baleen, or whale-bone, as it is called. [Footnote: The baleen or whale-bone I have described forms a most valuable portion of the produce afforded by the black whale, although not so valuable as the oil extracted from the same animal.] These filaments fill up the whole of the cavity of the mouth, and form a most complete strainer, so that only the most minute animals can enter. This is necessary, as the swallow is too small to admit even the smallest fish. When a black whale feeds, it throws up millions of small animals at a time with its thick lower lip, into the straining apparatus I have described; and as they are scarcely perceptible to the naked eye, when its vast size is considered some slight notion may be formed of the prodigious number it must consume at meal.