The prodigious forces discovered and exploited through many decades by the inventive genius and tireless energy of the European peoples seemed in the middle of the nineteenth century to carry them upwards to the very zenith of their power. The states of Europe might subsequently rule over dominions still more extensive, command armies still larger, and possess weapons more terrible by far in their destructive range; yet, as time went on, their supremacy would be increasingly open to challenge from the peoples of other continents. In the years 1830–70, however, it was scarcely questioned. This was a period when the European states were free from serious threat of political dominance by any one among them, and when, prone though they as ever were to shifting antagonisms, they were not more permanently divided into hostile and highly armed camps. Their wars were relatively brief and the loss of life relatively small. Conflict had not yet attained the suicidal proportions of 1914–18, and, although men of vision like Tocqueville and Gioberti could foretell the immense future power of the United States or Russia, it was not until after that first ‘world war’ that a European statesman would write of the decadence of Europe and a European thinker dilate upon the decline of the West.

This supremacy the European peoples owed above all to their near monopoly of the new skills and machines born of the Industrial Revolution and to the extraordinary and simultaneous increase in their own numbers. These phenomena had become manifest well back in the eighteenth century and had led intelligent men to ponder deeply upon their significance.