society would quickly run down to the simple reality of control by nature. Vast numbers would die in consequence.
Productive power, in short, is a far more important element of reality in relation to modern civilisation than is accumulated wealth. The total visible wealth of a civilised country, notwithstanding the antiquity of some of its treasures, is generally estimated as equal to the output of not more than seven or eight years. The significance of this statement does not lie in its precise accuracy, but in the rapid growth of its practical meaning for modem men, owing to their dependence on a machinery of production, mechanical and social, which in the past four or five generations has become increasingly delicate and complicated. For every advance in the application of science there has been a corresponding change in social organisation. It was by no mere coincidence that Adam Smith was discussing the division of labour when James Watt was inventing the steam-engine. Nor, in our own time, is it by blind coincidence that beside the invention of the internal combustion engine—the key to the motor-car, submarine, and aeroplane—must be placed an unparalleled extension of the credit system. Lubrication of metal machinery depends on