INTER-DEPENDENCE AND INTEGRATION. 405 



tion implies roads, vehicles, canals, boats and ships, which 

 can come into existence only as fast as the various kinds of 

 production develop ; and evidently these can develop only as 

 fast as the different articles produced in different localities 

 are interchanged by distributors. Once more, both there 

 developments depend on the development of an instrument 

 ality which substitutes purchase for barter. With a good 

 monetary system the resistance to exchange disappears; 

 relative values of things can be measured ; current prices can 

 be recognized; and there arises competition with all the 

 cheapenings, stimulations, and improvements resulting from 

 it. And that production and distribution may be thus facili 

 tated the medium of exchange has to be differentiated and 

 developed within itself; since, until to a metallic currency 

 there is added a currency of paper promises-to-pay, various 

 in their kinds, all the larger and remoter commercial trans 

 actions are greatly impeded. 



See, then, how great has become the interdependence. 

 Different kinds of production aid one another. Distribution, 

 while depending for its roads and vehicles on various kinds 

 of production, makes production more abundant and varied. 

 While a developed and differentiated currency furthers pro 

 duction and raises the rate of distribution. Thus, by their 

 mutual influences, the structures carrying on these processes 

 become more and more integrated. 



764. But no adequate idea of this integration can be 

 formed without contemplating other manifestations of it 

 more special in their kinds. 



First among these may be set down the cooperation of 

 separate processes and appliances in wider and more varied 

 ways. Some man, observing how a housemaid trundling a 

 mop dispersed the water, saw that by the aid of centrifugal 

 force various things might be dried and others separated. 

 Among results of his thought here are some. Masses of wet 

 sugar placed in a rotating drum with a perforated periphery, 



