which at the other end of the scale a London tradesman will spend on a restaurant dinner for the purpose of sitting at table with a duke--or the thousandth part of the sum which the same tradesman will spend in philanthropy or otherwise, for the sake of acquiring an empty title from a monarch who has lost all power of exercising any physical force whatsoever. Which process, judged by all things that men desire, gives the better result, the physical force of blood and iron which we see, or the intellectual or psychic force which we cannot see? The principle which operates in the limited fashion which I have indicated, operates with no less force in the larger domain of modern international politics. The wealth of the world is not represented by a fixed amount of gold or money now in the possession of one Power, and now in the possession of another, but depends on all the unchecked multiple activities of a community for the time being. Check that activity, whether by imposing tribute, or disadvantageous commercial conditions, or an unwelcome administration which sets up sterile political agitation, and you get less wealth--less wealth for the conqueror, as well as less for the conquered. The broadest statement of the case is that all experience--especially the experience indicated in the last chapter--shows that in trade by free consent, carrying mutual benefit, we get larger results for effort expended than in the exercise of physical force, which attempts to exact advantage for one party at the expense of the other. I am not arguing over again the thesis of the first part of this book; but, as we shall see presently, the general principle of the diminishing factor of physical force in the affairs of the world carries with it a psychological change in human nature which modifies radically our impulses to sheer physical conflict. What it is important just now to keep in mind, is the incalculable intensification of this diminution of physical force by our mechanical development. The principle was obviously less true for Rome than it is for Great Britain or America: Rome, however imperfectly, lived largely by tribute. The sheer mechanical development of the modern world has rendered tribute in the Roman sense impossible. Rome did not have to create markets and find a field for the employment of her capital. We do. What result does this carry? Rome could afford to be relatively indifferent to the prosperity of her subject territory. We cannot. If the territory is not prosperous we have no market, and we have no field for our investments, and that is why we are checked at every point from doing what Rome was able to do. You can to some extent exact tribute by force; you cannot compel a man to buy your goods by force if he does not want them, and has not got the money to pay for them. Now, the difference which we see here has been brought about by the interaction of a whole series of mechanical