settlement is a self-centered unit; and formerly this quality was even more evident than now, when industrial develop- ment has stirred some of the desert settlements out of their age-old lethargy. Unchanging as the fundamentals of desert economy must be, in general, there are certain modifications due to industrial development. Thus the influence of the large city of Iquique, which must subsist entirely upon im- ported foodstuffs, is spread over a large radius. Pica and Matilla supply a part of the fruit and vegetables consumed at the port and through the exchange have acquired a taste for the products of the town. Laborers are in high demand through the nitrate region, and the population of the oases, crowded from the standpoint of water supply and food re- sources, are often drawn upon for the services of the nitrate establishment, though the most important supply comes from the more densely populated south.
Farther south an important group of oases of which San Pedro de Atacama is the center enters into wider geographical relations with the nitrate districts. It lies at a much higher elevation in a distinct border zone partaking of the life of both mountain and desert. It will be described later (Ch, - XID) after the account of the trans-cordilleran cattle trade upon which it is primarily dependent.
The Development of the Nitrate Desert
In extreme contrast to the old self-sufficient communities of the piedmont oases are the new groupings dependent on the exploitation of mineral wealth. The first coast settlement between Arica and Copiapé to attain any importance was the little Changos settlement of Cobija (latitude 22° 30’ S.) established early in the eighteenth century as a customs house for suppression of active contraband trade in silver from the Bolivian mines,
Following the Wars of Liberation the first notable new development on the coast of Atacama was the resurrection of the port in 1829. The first step undertaken was careful organization of the water supply. The best well close to the
