The people of whom I have been speaking are principally the men of the First Stone Age, when the art of polishing tools and weapons had not been found out. They simply chipped these things out of the flints and left them very rough; but the men of the next, or Second Stone Age, made great improvements. They ground their flint knives and axes with other stones, and rubbed them down to sharp edges and points, so that they must have been much more useful for killing and cutting up the animals they hunted. All their bone and horn tools are much better made, and sometimes ornamented prettily with marks cut upon them. The Second Stone Age men evidently wore clothing, most probably made of the skins of animals—for the long strips of bone with a hole at one end which you see in the picture could not have been used for any other purpose, except to draw threads through something. The threads were very likely either the sinews of animals pulled out of the flesh, or thin strips of their skins, or perhaps the inner bark of a tree twisted into a kind of string. In the colder parts of Europe and America these ancient people would need some protection from the weather. How then did the people of the First Stone Age manage, if they had no bone needles, as I think they had not, with which to make clothing? They must have wrapped themselves in the skins just as they came from the backs of the animals. It is not easy to be always sure, when we find a cave and all these relics of pre-historic man, whether the inhabitants belonged to the First or the Second Stone Age. Sometimes there are signs of polishing and grinding on the tools, and then we may suppose that men were gradually getting more skilful, until they finished off all their weapons beautifully. But there is such a very great difference in the perfection of these useful articles found in some places and those found in others that we have no doubt men made slow progress, from the rough or First Stone Age, to the polished or Second Stone Age.