There are other species of whales which are useful, in a certain degree, to mankind, for the oil that is yielded by their bodies; but few of them are objects of pursuit, on account of the difficulty there is in killing them, or of the very inferior quantity of oil which they afford. The blades of their whalebone are also too small to be of any use as an object of commerce. 120. _The BLUNT-HEADED CACHALOT, or SPERMACETI WHALE_ (Physeter macrocephalus) _is a marine animal from sixty to seventy feet in length, with large teeth in the under jaw, which fit into corresponding sockets of the upper jaw; the orifice of the spiracle single, and at the upper part of the extremity of the muzzle; and without any fin upon the back._ _The head occupies about one-third of the length of the whole body. The colour of this whale is generally black, but, in the old animals, the under parts become whitish. The skin is smooth, oily, and almost as soft to the touch as silk._ _It is most frequently seen in the northern ocean, in the latitudes of Greenland, Spitzbergen, and Iceland; yet it is occasionally observed off the British coasts, and sometimes even in the Mediterranean._ Lucrative as the several parts of these animals are, the whale-fishers have a great dread of them, in consequence of their astonishing activity in the water. Much care is requisite, in striking the harpoon, to keep the boats out of danger of being overturned, and great dexterity in following their track. From the relation given by the Danish voyagers Olafsen and Povelsen, it would appear that the spermaceti whales become occasionally so ferocious as even to seize the fishing boats with their teeth, and, in an instant, to destroy the whole crew. Notwithstanding all these dangers, so highly valued are they that they are searched for with much assiduity: and happy are the owners of those vessels which can obtain the greatest number of them. The _oil_ that is obtained from them is not in great quantity, but is of excellent quality. In burning it yields a bright flame, without exhaling any noxious smell.