O NE of the principal characteristics of modern technically advanced nations is the use of large amounts of inanimate power. Cheap, reliable, and adequate power is necessary not only for the development of large-scale manufacturing but also for innumerable other uses, such as the maintenance and extension of transportation facilities and the improvement of agricultural practices and processes, and for the countless amenities of life that are commonplace in areas of Northwest European culture. In fact, so important is power that it is often used as a rough index of economic development.