support four times the population, though the condition of the lowest stratum may not be better. And this amazing advance of wealth is not due to the fact that Englishmen of to-day have better brains for mathematics than the Englishmen of Newton's time; but to the accumulation of capital, the improvement of the natural conditions of the soil, the turning to account of vast masses of material, previously neglected; to the invention of machinery, and so forth; all of which imply, not necessarily the very slightest improvement of natural capacity, but simply the growth of knowledge, and the fact that each generation has preserved more than it has consumed. What we call progress or civilisation, which means, whatever else it may or may not mean, a gigantic increase in the power of man over nature, is due, therefore, to the one fact that man can accumulate. He can modify the earth in such a way as to facilitate the labours of the coming generations; he can make tools which last beyond his own time, and which themselves become, as it were, the ancestors of incomparably superior tools; he can, moreover, accumulate and transmit knowledge, not merely the knowledge of facts, but the knowledge of scientific laws and of useful inventions, and of the right methods of investigating facts. When Newton made a discovery, he made it for all the following generations; and, though it may well be that no superior or even equal intellect has since arisen to carry on his work, the dwarf now stands on the shoulders of the giant. It is not simply that we know more facts. The modes of mathematical inquiry differ as much from those which Newton could employ, as the latest steam engine from the crude fire machine before the time of Watt; and an average undergraduate can solve with ease problems which once puzzled the greatest intellects that ever appeared among men. Man, then, can accumulate; and that simple fact enables every generation enormously to surpass its predecessors. Accumulation, again, is, of course, a form of inheritance. We are born heirs to the intellectual as well as to the material fortunes of our ancestors. But, it is obvious, this is something very different from heredity. It supposes an alteration, not in the man, but in his surroundings or his education in the widest sense; not in his intellectual capacity, but in the knowledge which it can attain and the rules which it has worked out. In order that a man may be capable either of bequeathing or inheriting, he must have certain faculties; he must be an observing, remembering, reasoning animal; but he may become indefinitely richer, not from any improvement in his powers of observing and remembering and using, but simply from the change in his position. People's memories, it is sometimes suggested, have been weakened by the invention of printing. But, weakened or not, we have an incomparably greater knowledge of the past than was formerly