2. When we come to the cave-dwellers we see marked signs of a higher civilization. The first and most important of these signs undoubtedly is the _evidence_ of knowledge how to procure fire. We see a much greater variety in the implements used by the cave-dwellers. This, no doubt, is due _in part_ to the disappearance of a portion of the implements of the drift age; but still we must take things as we find them. And putting side by side the specimens of the drift-implements and the cave-implements, we are at once struck by the superiority of the latter in make and in variety of form. Thirdly, as has already been pointed out, we have here the earliest traces of art. On that subject it is not necessary again to dwell. * * * * * 3. And now pass on to the second stone age, and see what progress man has made in the interval which separates the two periods. We begin with the society represented by the kitchen-middens. We do not possess any certainly polished-stone implements from these refuse-heaps. But I do not lay any great stress upon the invention of the art of polishing or even of grinding the stone; though that was not without importance, for it enabled the men of the second stone age to make use of much harder and more durable sorts of stone for their cutting implements. The earliest stone-age men made their implements of all sorts almost exclusively of flints, because the flint was a stone not difficult to chip into shape and to give an edge to by chipping. But when it comes to polishing or grinding instead of chipping an edge upon stones, there are a variety of other kinds of stone which are much more durable and much more serviceable than flints are, for the very reason that they are not liable to chip, and these stones (jade, granite, greenstone, obsidian, or one or other of the marbles, for example) we find a good deal employed during the latter stone age. What, however, is more significant than would be the use of polished-stone implements by the kitchen-midden men is the evidence of their use of canoes, and therefore the evidence that they understood the art of navigation. Next after that we must place the use of the bow, which also was probably known to the earliest men of the polished-stone age, but not to those of the preceding era. Finally, we have the beginning of domestication of animals in the domestication of the dog. But we have as yet no beginning of agriculture. * * * * *