1835.] BAY OF CALLAO. 349 



seems to have been deposited as the laud slowly rose above the 

 level of the sea. The salt is white, very hard, and compact : it 

 occurs in water-worn nodules projecting from the agglutinated 

 sand, and is associated with much gypsum. The appearance of 

 this superficial mass very closely resembled that of a country after 

 snow, before the last dirty patches are thawed. The existence of 

 this crust of a soluble substance over the whole face of the country, 

 shows how extraordinarily dry the climate must have been for a 

 long period. 



At night I slept at the house of the owner of one of the saltpetre 

 mines. The country is here as unproductive as near the coast ; 

 but water, having rather a bitter and brackish taste, can be pro- 

 cured by digging wells. The well at this house was thirty-six 

 yards deep : as scarcely any rain falls, it is evident the water is 

 not thus derived ; 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 conclude that it 

 percolates under ground from the Cordillera, though distant many 

 leagues. In that direction there are a few small villages, where 

 the inhabitants, having more water, are enabled to irrigate a little 

 land, and raise hay, on which the mules and asses, employed in 

 carrying the saltpetre, are fed. The nitrate of soda was now 

 selling at the ship's side at fourteen shillings per hundred pounds : 

 the chief expense is its transport to the sea-coast. The mine 

 consists of a hard stratum, between two and three feet thick, of the 

 nitrate mingled with a little of the sulphate of soda and a good 

 deal of common salt. It lies close beneath the surface, and follows 

 for a length of one hundred and fifty miles the margin of a grand 

 basin or plain ; this, from its outline, manifestly must once have 

 been a lake, or more probably an inland arm of the sea, as may be 

 inferred from the presence of iodic salts in the saline stratum. 

 The surface of the plain is 3300 feet above the Pacific. 



ISth. We anchored in the Bay of Callao, the seaport of Lima, 

 the capital of Peru. We stayed here six weeks, but from the 

 troubled state of public affairs, I saw very little of the country. 

 During our whole visit the climate was far from being so delight- 

 ful, as it is generally represented. A dull heavy bank of clouds 

 constantly hung over the land, so that during the first sixteen days 

 I had onlv one view of the Cordillera behind Lima. These moun- 



