178 THE POPULAR SCIENCE MONTHLY 



greater than the entire population of Britain. The total British coal 

 production at present — 290,000,000 tons yearly — consequently repre- 

 sents a working capacity more than ten times that of the whole popula- 

 tion in terms of men, while the annual export of coal from Britain is 

 equal to the emigration of ten million laborers. 



Every horse power of available mechanical energy, therefore, should 

 be estimated, not simply as a form of power permitting the use of appli- 

 ances and processes which neither human nor animal energy could make 

 available, but also as so many added members of the population which do 

 not make any increased demands on the soil for food and the materials of 

 clothing or shelter. The possession of this resource in abundance has, 

 in the past, permitted nations to develop at a rate, or to an extent, 

 which bore no relation to their ability to supply locally the necessities 

 of life: the development instead being on a basis of exchanging the 

 products of their mechanical power for the materials of food and cloth- 

 ing. This existence on a basis of exchange, however, involves the 

 operation of two fundamental conditions. First, the important utiliza- 

 tion of power does not appear until national development has passed 

 beyond the stage of scanty population, hence it is logically one of the 

 later stages of evolution. Second, the exchange depends on the exist- 

 ence of other national areas still in the early stages of evolution, not 

 taxing their opportunities to their full capacity, and consequently 

 capable of yielding a surplus of the fundamental necessities of life. 



Such excessive development through the operation of one physical 

 factor which temporarily overtops all others, as has resulted from the 

 use of coal in Germany, for example, however strong the nation may 

 appear at the time, is not a safe measure of the true strength and 

 permanence of the nation. It may subsequently be greatly reduced by 

 the natural changing of conditions, for unless the nation possesses in 

 itself some ready substitute for coal when its supply is exhausted, as it 

 inevitably will be exhausted comparatively soon for most nations, that 

 nation must look forward to a future in which there are likely to be 

 necessary certain sharp readjustments, with respect to its ability to 

 take care of its own people. Moreover, as the nations now producing 

 a surplus of necessities continue to advance in their own evolution and 

 trend toward the maximum of their own capacity to feed, clothe and 

 shelter a population, other readjustments, of perhaps even more sweep- 

 ing character, may be necessary in those places where extensive growth 

 has been based primarily on tlie means of generating mechanical energy. 

 The stage wherein national importance in industry, commerce and 

 population is derived from resources of coal is in any case transitory, 

 and represents only one step in the gradual adjustment of all nations 

 to their physical surroundings. 



Water power in abundance, on the contrary, may be regarded as an 



