geographical revolution transformed the earth's surface. "It introduced a new race of men," writes H. de B. Gibbins, "men who work with machinery instead of with their hands, who cluster together in cities instead of spreading over the land, men who trade with those of other nations as readily as with those of their own town, men whose workshops are moved by the great forces of nature and whose market is no longer the city or country but the world itself." Measured by the crude standards of gross wealth and numbers, the people of the earth have flourished mightily since the dominion of coal began. The aggregate wealth of the world has increased to fabulous proportions. The average expectation of life among Western peoples has doubled. Between 1800 and 1910 the world's population rose from approximately 640,000,000 to 1,616,000,000. The population of England, which had increased only fifteen per cent from 1651 to 1751, increased two hundred per cent during the next century. Between 1816 and 1910, the population of France increased fifty per cent, of Germany three hundred per cent, of the United States seventeen hundred per cent. Moreover the drive of coal's energy immensely stimulated men's inventive faculties. It transformed Kay's "flying shuttle" and Hargreaves' "spinning jenny" from clever toys into instruments of large-scale production, the crude steam engines of Newcomen and Watt into the great modern locomotive and the turbine engine; it made possible the large-scale production of telegraph wires and ocean cables, the cylinder press and typesetting machines, the electrical dynamo, the internal-combustion engine, the aeroplane, and even the space-ranging modern telescope. It lifted the veil from the seven seas, broke down the physical barriers between the peoples of the earth, forged the steel framework of national and international government. The commercial and political primacy which England held for more than one hundred and fifty years rested upon her abundant fields of easily accessible coal. The cosmic energy flowing out from her mines spread her trade and her surplus population to the four corners of the earth and made her triumphant over Spain and Holland--nations poor in coal. The coal of Westphalia, associated with the iron ores of Lorraine, welded the States of Germany into the empire of the latter nineteenth century and hurled her green-grey armies across her frontiers in the mad adventure of 1914. The vast, rich coal fields of North America have transformed the United States from an agricultural appanage of Europe into the foremost manufacturing and commercial nation in the world. The future of Russia lies largely in the coal fields of the Donetz basin. The imperfectly surveyed coal and ore fields of China and Siberia are probably the strongest of the magnets drawing the Powers into the problem of the Pacific. Coal and the continuing industrial revolution are still shaping the destiny of mankind.