TRANSFORMATION AND EQUIVALENCE OF FORCES. 227 



there can be but a small total of results in the shape of art- 

 products and scientific discoveries. The correlation 

 of the social with the physical forces through the inter- 

 mediation of the vital ones, is, however, most clearly shown 

 in the different amounts of activity displayed by the same 

 society according as its members are supplied with different 

 amounts of force from the external world. In the effects of 

 good and bad harvests, we yearly see this relation illustrated. 

 A greatly deficient yield of wheat is soon followed by a 

 diminution of business. Factories are worked half-time, or 

 close entirely; railway traffic falls; retailers find their sales 

 much lessened; house-building is almost suspended; and if 

 the scarcity rises to famine, a thinning of the population still 

 more diminishes the industrial vivacity. Conversely, an 

 unusually abundant harvest, occurring under conditions not 

 otherwise unfavourable, both excites the old producing and 

 distributing agencies and sets up new ones. The surplus so- 

 cial energy finds vent in speculative enterprises. Capital 

 seeking investment carries out inventions that have been 

 lying unutilized. Labour is expended in opening new chan- 

 nels of communication. There is increased encouragement 

 to those who furnish the luxuries of life and minister to the 

 aesthetic faculties. There are more marriages, and a greater 

 rate of increase in population. Thus the social organism 

 grows larger, more complex, and more active. When, 

 as happens with most civilized nations, the whole of the ma- 

 terials for subsistence are not drawn from the area inhabited, 

 but are partly imported, the people are still supported by 

 certain harvests elsewhere grown at the expense of certain 

 physical forces. Our own cotton-spinners and weavers 

 supply the most conspicuous instance of a section in 

 one nation living, in great part, on imported commodi- 

 ties, purchased by the labour they expend on other im- 

 ported commodities. But though the social activities 

 of Lancashire are due chiefly to materials not drawn 

 from our own soil, they are none the less evolved from 



