We have seen, so far, that the early traces of man’s existence point to a gradual improvement in the state of his civilization, to the acquirement of fresh knowledge, and the practice of fresh arts. The rude stone implements of the early drift-period are replaced by the more carefully manufactured ones of the polished-stone age, and these again are succeeded by implements of bronze and of iron. By degrees also the arts of domesticating animals and of tilling the land are learnt; and by steps, which we shall hereafter describe, the art of writing is developed from the early pictorial rock-sculptures. Now, in order that each step in this process of civilization should be preserved for the benefit of the next generation, and that the people of each period should start from the vantage-ground obtained by their predecessors, there must have been frequent intercommunication between the different individuals who lived at the same time; so that the discovery or improvement of each one should be made known to others, and become part of the common stock of human knowledge. In the very earliest times, then, men probably lived collected together in societies of greater or less extent. We know that this is the case now with all savage tribes; and as in many respects the early races of the drift-beds seem to have resembled some now existing savage tribes in their mode of life, employing, to a certain extent, the same implements, and living on the same sort of food, this adds to the probability of their gregariousness. The fact, too, that the stone implements of the first stone period have generally been found collected near together in particular places, indicates these places as the sites of early settlements. Beyond this, however, we can say very little of the social state of these early stone-age people. Small traces of any burial-ground or tomb of so great an antiquity have yet been found, and all that we can say of them with any certainty is, that their life must have been very rude and primitive. Although they were collected together in groups, these groups could not have been large, and each must have been generally situated at a considerable distance from the next, for the only means of support for the men of that time was derived from hunting and fishing. Now it requires a very large space of land to support a man who lives entirely by hunting; and this must have been more particularly the case in those times when the weapons used by the huntsman were so rude, that it is difficult for us now to understand how he could ever have succeeded in obtaining an adequate supply of food by such means. Supposing that the same extent of territory were required for the support of a man in those times as was required in Australia by the native population, the whole of Europe could only have supported about seventy-six thousand inhabitants, or about one person to every four thousand now in existence.