After 1870 there was developed on a large scale an unprecedented situation, and the economic condition of Europe became during the next fifty years unstable and peculiar. The pressure of population on food, which had already been balanced by the accessibility of supplies from America, became for the first time in recorded history definitely reversed. As numbers increased, food was actually easier to secure. Larger proportional returns from an increasing scale of production became true of agriculture as well as industry. With the growth of the European population there were more emigrants on the one hand to till the soil of the new countries, and, on the other, more workmen were available in Europe to prepare the industrial products and capital goods which were to maintain the emigrant populations in their new homes, and to build the railways and ships which were to make accessible to Europe food and raw products from distant sources. Up to about 1900 a unit of labor applied to industry yielded year by year a purchasing power over an increasing quantity of food. It is possible that about the year 1900 this process began to be reversed, and a diminishing yield of Nature to man's effort was beginning to reassert itself. But the tendency of cereals to rise in real cost was balanced by other improvements; and--one of many novelties--the resources of tropical Africa then for the first time came into large employ, and a great traffic in oil-seeds began to bring to the table of Europe in a new and cheaper form one of the essential foodstuffs of mankind. In this economic Eldorado, in this economic Utopia, as the earlier economists would have deemed it, most of us were brought up. That happy age lost sight of a view of the world which filled with deep-seated melancholy the founders of our Political Economy. Before the eighteenth century mankind entertained no false hopes. To lay the illusions which grew popular at that age's latter end, Malthus disclosed a Devil. For half a century all serious economical writings held that Devil in clear prospect. For the next half century he was chained up and out of sight. Now perhaps we have loosed him again.