382 NORTHERN CHILE chap. 



may have been greater. As the peculiarly arid character of the 

 climate is evidently a consequence of the height of the 

 Cordillera, we may feel almost sure that before the later 

 elevations, the atmosphere could not have been so completely 

 drained of its moisture as it now is ; and as the rise has been 

 gradual, so would have been the change in climate. On this 

 notion of a change of climate since the buildings were inhabited, 

 the ruins must be of extreme antiquity, but I do not think 

 their preservation under the Chilian climate any great difficulty. 

 We must also admit on this notion (and this perhaps is a 

 greater difficulty) that man has inhabited South America for an 

 immensely long period, inasmuch as any change of climate 

 effected by the elevation of the land must have been extremely 

 gradual. At Valparaiso, within the last 220 years, the rise 

 has been somewhat less than 19 feet: at Lima a sea- beach has 

 certainly been upheaved from 80 to 90 feet, within the Indio- 

 human period : but such small elevations could have had little 

 power in deflecting the moisture-bringing atmospheric currents. 

 Dr. Lund, however, found human .skeletons in the caves of Brazil, 

 the appearance of which induced him to believe that the 

 Indian race has existed during a vast lapse of time in South 

 America. 



When at Lima, I conversed on these subjects ^ with Mr. 

 Gill, a civil engineer, who had seen much of the interior country. 

 He told me that a conjecture of a change of climate had some- 

 times crossed his mind ; but that he thought that the greater 

 portion of land, now incapable of cultivation, but covered with 

 Indian ruins, had been reduced to this state by the water- 

 conduits, which the Indians formerly constructed on so 

 wonderful a scale, having been injured by neglect and by 

 subterranean movements. I may here mention that the 

 Peruvians actually carried their irrigating streams in tunnels 

 through hills of solid rock. Mr. Gill told me he had been 

 employed professionally to examine one ; he found the passage 

 low, narrow, crooked, and not of uniform breadth, but of very 

 considerable length. Is it not most wonderful that men should 



^ Temple, in his travels thiough Upper Peru, or Bolivia, in going from Potosi to 

 Oruro, says, " I saw many Indian villages or dwellin<;s in ruins, up even to the very 

 tops of the mountains, attesting a former jiopulation where now all is desolate." 

 He makes similar remarks in another place ; but I cannot tell whether this desolation 

 has been caused by a want of population, or by an altered condition of the land. 



