THE SPATIAL ORIGIN OF COMMERCE*
研究了分散与集中对生产率的不同影响，发现中间商在区域中心聚集能缓解空间矛盾，使城市作为中间贸易平台存在，无需生产、运输或交换的规模报酬递增。
Although dispersion raises productivity by relieving crowding, concentration promotes trade. The participation of specialist middlemen, who tend to cluster around the regional center, in the trading process would mitigate such tensions, for it becomes less urgent for others to scramble for central locations then from the increase in the density of economic activities around such locations. A city, populated by a cluster of middlemen, that serves as a platform for intermediate trade among producers in surrounding areas can exist without any increasing returns in production, transportation, and exchange. Indirect trade and pure commerce may, thus, have a spatial origin.