Now that it has been hunted so much, apparently the sperm-whale does not grow to so great a size as it did in days gone by. Yet it is a very big animal, for a full-grown male will attain to a length of sixty or even seventy feet, while even a baby whale is from eleven to fourteen feet long, or as big as a big walrus. And, strange to say, the head is almost as large as the body and tail put together. This is chiefly due to the fact that there is a great cavity in the skull, which contains the valuable substance we call spermaceti. When one of these whales is killed, the head is cut off, and a kind of well is dug in the forehead, from which the spermaceti is drawn to the surface in buckets, as much as thirty barrels being sometimes taken from a single animal. Besides this, the blubber yields a large quantity of very valuable oil, which burns with a much clearer and stronger light than ordinary whale-oil. And sometimes a curious substance called ambergris is found in its body. It is used in making certain kinds of scent, and is quite costly, although as much as fifty pounds of it have sometimes been taken from a single whale. Sperm-whales are generally seen in companies, which are known as schools. In olden days there were sometimes as many as two hundred whales in one of these schools. But so many of the great creatures have been killed by whalers that it is now quite the exception to see more than four or five together. These whales are very playful creatures, and may often be seen gamboling on the surface of the sea, and now and then breaching, or leaping completely out of the water and falling back again with a tremendous splash. They feed chiefly upon the great cuttles, or squids, which are so plentiful in some parts of the ocean, but also devour large numbers of cod and other fishes. But how they manage to catch these fishes nobody quite seems to know. These whales were formerly hunted by means of a small boat, in the bow of which stood a man with a long spear, or harpoon, in his hand, attached to an enormous coil of rope. As soon as this was hurled at a whale the boat was backed, so as to escape the stroke of its tail, and the whale would then sound, or dive to the depth of perhaps three-quarters of a mile. As soon as he rose he was driven down again, as already described, before he had had time to finish spouting, and at last, when quite exhausted, was killed by means of a very long and sharp-edged lance. Nowadays, however, the harpoon is generally fired from a ship by means of a gun, and as a charge of gun-cotton is placed in the harpoon's head, which explodes as soon as the weapon enters the body of the whale, such a severe wound is caused that the animal very soon dies. BOTTLE-NOSED WHALES