Twenty feet high their nesting-homes often are, and pyramidal in shape. Wild cattle can climb upon them with impunity without crushing them, the walls are so solid. A dozen men can find shelter in some of their chambers, and native hunters do often lie in wait inside them when out after wild animals. They construct galleries also which are as wide as the bore of a large cannon, and which run three and four feet underground. The nests are said to be five hundred times as high as the ant's body, and it has been estimated that if we built our houses as high, proportionately, they would be four or five times as high as the pyramids of Egypt, on which we look with such wonder and awe. In speaking of the havoc some ants make, let us also remember some good service rendered. In the West Indies there is a red cockroach which is four times as large as the English one. It smells horridly, and scents everything that it touches, is far more destructive than the ant, and quite omnivorous. Now, although one cockroach in bulk outweighs two hundred ants, the latter little creatures kill and devour innumerable cockroaches. Whenever an ant comes upon a cockroach that is at rest, eating, or in its hole, suddenly myriads appear, swarm round it, as if by magic, surround it completely, and then, with one consent, rush all over it, and as it is dragged away, you see only a mass of ants moving along. All the time they carry they are busily devouring it, until only its shell is left. We read also that in forests in Switzerland and Sweden the ants form lofty hillocks which serve as a compass to travellers who have lost their way by night or in a fog. The nests being always made from east to west, their peak is at the east end, which is steep, the ridge sloping, however, gently down to the nest. So the wanderer can tell from these ant-hills in which direction he ought to go. Tamerlane, the great Tartar prince, learned a helpful lesson from an ant once, when he had taken refuge from the pursuing enemy in a ruined building. Having to stay there for hours, at the end of his resources, ready to give way to despair, his attention was attracted by an ant which was carrying something larger than itself up a high wall. Noticing that it often let its burden drop, he began to count the number of times that it began the ascent again, and he found that sixty-nine times it failed, its burden falling to the ground. The seventieth time was a success. "This sight," he said, "gave me courage at the moment, and I have never forgotten the lesson it taught me."