In the middle of the eighteenth century the steam engine began to supplant the muscular power of men and animals, which had theretofore been only feebly supplemented by windmills and water wheels. And now we use steam and gas engines and water power to generate potent electric currents which do their work far from the source of supply. Mechanical ingenuity has utilized all this undreamed-of energy in innumerable novel ways for producing old and new commodities in tremendous quantities and distributing them with incredible rapidity throughout the earth. Vast factories have sprung up, with their laborious multitudes engaged on minute contributions to the finished article; overgrown cities sprawl over the neighboring green fields and pastures; long freight trains of steel cars thunder across continents; monstrous masses of wealth pile up, are reinvested, and applied to making the whole system more and more inconceivably intricate and interdependent; and incidentally there is hurry and worry and discontent and hazard beyond belief for a creature who has to grasp it all and control it all with a mind reared on that of an animal, a child, and a savage. As if these changes were not astounding enough, now has come the chemist who devotes himself to making not new _commodities_ (or old ones in new ways), but new _substances_. He juggles with the atoms of carbon, hydrogen, oxygen, nitrogen, chlorine, and the rest, and far outruns the workings of nature. Up to date he has been able to produce artfully over two hundred thousand compounds, for some of which mankind formerly depended on the alchemy of animals and plants. He can make foodstuffs out of sewage; he can entrap the nitrogen in the air and use it to raise wheat to feed, or high explosives to slaughter, his fellows. He no longer relies on plants and animals for dyes and perfumes. In short, a chemical discovery may at any moment devastate an immemorial industry and leave both capital and labor in the lurch. The day may not be far distant when, should the chemist learn to control the incredible interatomic energy, the steam engine will seem as complete an anachronism as the treadmill. The uttermost parts of the earth have been visited by Europeans, and commerce has brought all races of the globe into close touch. We have now to reckon with every nation under heaven, as was shown in the World War. At the same time steam and electrical communication have been so perfected that space has been practically annihilated as regards speech, and in matters of transportation reduced to perhaps a fifth. So all the peoples of the earth form economically a loose and, as yet, scarcely acknowledged federation of man, in which the fate of any member may affect the affairs of all the others, no matter how remote they may be geographically.