A HARMONIZATION OF FIRST AND SECOND NATURES*
研究第一自然（区位优势）和第二自然（集聚经济）如何共同影响产业选址，发现绝对区位优势导致平稳集聚，比较优势则引发突变式集聚。
ABSTRACT This paper investigates the joint impact of the first nature and the second nature forces on industry location. Toward this aim, we develop a two-region new economic geography model where local factor congestion and location advantages compete with demand linkages and product market crowding. In particular, we study the case of absolute location advantage in a single industry model and the case of comparative advantages in a two-industry model. We characterize the structure of industries and discuss the possibilities of catastrophic changes, endogenous industrial asymmetries and specialization. We find that absolute location advantage are associated with a smooth agglomeration process and comparative advantages with a catastrophic process.