July, 1835. IQUIQUE. 445 



may be, the existence of a crust of a soluble substance over the 

 whole face of the country, shows how extraordinarily dry the 

 climate must have been for a period long antecedent. 



At night I slept at the house of the oisTier of one of the 

 saltpetre mines. The country is here equally unproductive 

 with that near the coast ; but water, though having rather a 

 bitter and brackish taste, can be procured by digging. The 

 well at this house was thirty- six yards deep. As scarcely 

 any rain falls, it is evident the water is not derived from 

 that source ; indeed if it were, it could not fail to be as salt 

 as brine, for the whole surrounding country is incrusted 

 with various saline substances. We must therefore con- 

 clude that it percolates from some distant and more humid 

 region, probably the mountains of the higher Cordillera. In 

 that direction there are a few small villages, such as Tarapaca, 

 where the inhabitants, having more water, are enabled to 

 irrigate some little land, and produce hay, on which the 

 mules and asses employed in carrying the saltpetre are fed. 



The nitrate of soda is sold at the ship^s side at fourteen 

 shillings per hundred pounds. The chief expense is the tran- 

 sport to the sea-coast. The mine itself consists of a stratum 

 between two and three feet thick, of the hard and nearly pure 

 salt, lying close beneath the surface. The stratum follows the 

 margin of a grand basin or plain, which manifestly must once 

 have been either a lake or inland sea : the elevation at present 

 is 3300 feet above the level of the Pacific. On our return we 

 made a detour by the mines of Guantajaya. The village 

 consists solely of the houses of the miners, and the place is 

 utterly destitute of every necessary ; — even water being 

 brought thirty miles on the backs of animals. At present 

 the mines yield little ; though formerly they were very pro- 

 ductive. One has a depth of four hundred yards, and out of 

 it masses of silver were taken so pure, that it was only re- 

 quired to melt them in order to run them into bars. We 

 reached Iquique after sunset : I went on board, and then the 

 Beagle weighed for Lima. I Avas very glad to have seen 



