128 PRINCIPLES OF RURAL ECONOMICS 



or locations. Such high prices or ground rents are paid for space 

 in these centers that many enterprises are forced to locate at a 

 distance from the center in order to avoid the tremendous ex- 

 pense of a central location. Thus a recessive tendency shows 

 itself, a countermovement away from the more densely pop- 

 ulated areas toward the suburbs. But the fact that there is such 

 severe competition for the central locations, when the advantages 

 for physical production are no greater, but where the opportuni- 

 ties are better for selling the products or buying the raw mate- 

 rials, shows how thoroughly urban industries and urban peoples 

 are dominated by the question of markets, and how they therefore 

 tend to concentrate themselves in more and more densely pop- 

 ulated centers. Even the dispersive tendency noted above is 

 usually not strong enough to offset the tendency of large cities 

 to grow more rapidly than small cities and towns. 



Again, there are sometimes marked physical advantages, like 

 mines, water power, building materials, etc., which explain the 

 location of a city. These physical advantages may be of limited 

 extent or quantity. When the city has grown to the limit set by 

 the natural physical advantage, there is sometimes a tendency 

 for the increasing or surplus population to move to a new loca- 

 tion where new and unused physical advantages are to be found. 

 Thus new and small towns sometimes actually grow at the ex- 

 pense of the older and larger ones. This is particularly the 

 case when new mines are opened, but it sometimes follows the 

 development of a new source of power, such as water power. 

 These are almost the only cases where the movement of urban 

 populations is not determined by a search for markets. Being 

 determined by a search for natural resources, which might be in- 

 cluded in a definition of land, this movement resembles the move- 

 ment of rural populations, which is determined by the search 

 for land. But cities of this type are exceptions to the general 

 rule and do not themselves represent the general tendency of 



