390 



ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1908. 



influence of the trade winds. Clouds fire not seen passing to the 

 Cordillera from the Pacific. The mists of the coast which drift in- 

 land from the Pacific form at the season when the sky in the Cor- 

 dillera is clear and their movements are with the land and sea breezes. 

 Systematic observations of the rainfall in the Andes region have been 

 carried on at only one locality, namely, Cailloma, which is situated 

 north of Arequipa and just to the east of the Continental Divide. 



From the published data 

 the writer has constructed 

 the accompanying dia- 

 grams (figs. 3 and 4) 

 which show the annual 

 and monthh^ variations 

 of the rainfall. 



The Cordilleras of the 

 Andes. 



Description by Humboldt, 

 1802. 



Although Humboldt 

 did not have Peru as an 

 object of special study 

 and did not visit the 

 country excepting to see 

 the coast at Pisco and 

 Lima and to travel in the 

 northern highlands be- 

 tween Cajamarca and the 

 Maranon,*^ he neverthe- 

 less gave a graphic and 

 to a large extent a correct 

 description of the chain 

 of the Andes, availing 

 himself of data furnished 

 by others. He says, in sub- 

 stance, that in southern 

 Peru there are two branches of the Andes Avhich include between 

 them the Titicaca basin. To the north of the Titicaca basin there 

 is a knot which includes Vilcanota, Carabaya, Abancay, Huando, 

 and Parinacochas. After this knot of Cuzco and Parinacochas, in 

 latitude 14° S., the Andes present a second bifurcation, and north- 

 ward the two chains lie on the east and west of the river Jauja. 



Fig. 3. 



-Annual variation of rainfall at Cailloma 

 during seven years. 



° Raimondi, El Peru, Volume I, page 15. 



