no DISCOVERY REPORTS 



coast, from lat. 4° S to lat. 32° S, may be described as a desert : on this western coast, northward of 

 lat. 4° S, where the trade wind loses its regularity, and heavy torrents of rain fall periodically, the 

 shores of the Pacific, so utterly desert in Peru, assume near Capo Blanco the character of luxuriance 

 so celebrated at Guayaquil and Panama. Hence in the southern and northern parts of the continent, 

 the forest and desert occupy reversed positions with regard to the Cordillera, and these positions are 

 apparently determined by the direction of the prevalent winds. 



These features are illustrated in Plate XIV. But for certain details of meteorology, as, 

 for example, the implication that trade winds traverse the Cordillera, for which the reader 

 is referred to pp. 124 and 195, the description is as apt on the centenary of his visit 

 as on the day it was made. The Peru Coastal Current reaches its normal development 

 off that arid strip of the west coast described by Darwin as falling between the luxuriant 

 forests of Ecuador and the rank vegetation of the Patagonian Islands, that is between 

 the parallels of 4° S lat. and 32-40° S lat. 



Under abnormal conditions a reversal of the current brings hot equatorial water 

 southwards along the coasts of Peru. This counter-current, usually known by the name 

 El Nino,^ is a seasonal occurrence of varying severity and happens usually in the 

 months of January to March. With the hot counter-current come northerly wind and 

 heavy rains which in some years work havoc on a coast that normally enjoys a dry climate 

 and where the majority of buildings are of mud (adobe). In the sea the effects are 

 equally disastrous. Fish and the lesser forms of life are killed by the sudden rise of 

 temperature and drift on to the shore in enormous quantity. Widespread putrefaction 

 ensues, and sulphuretted hydrogen emitted with other decomposition products blackens 

 the paintwork of ships lying in harbour. This has come to be called the " Callao Painter ", 

 and locally by the name of aguaje. The loss of food is at once felt by the guano birds, 

 which leave their rookeries. The young, deserted in their nests, are the first to perish, 

 but adults also die or succumb to disease with great loss to the guano industry. 



HISTORICAL 



Many theories have been put forward to explain the presence of cool water on the 

 Peruvian and Chilean coasts. Humboldt's classic hypothesis was published in 181 1 

 after his visit to the west coast ; but his were by no means the first of the observations 

 about this interesting region.^ 



In 1543, within eleven years of Pizarro's conquest, Zarate was sent to Peru as 

 Treasurer-General by order of the King of Spain, and his account of the country is 

 recognized as one of the most authoritative of the early records. Accuracy on points of 

 fact and recognition of essential problems make his geographical observations of great 

 interest. They are contained in the following extract from Kerr's translation : 



It may appear difficult to some of my readers to comprehend why no rain should fall in the plain 

 of Peru, considering that the country is bounded along the whole of one side by the sea, where many 



1 Carrillo (1892) states that the counter-current is called "El Niiio" (meaning "the child") by local fisher- 

 men because it is most noticeable after Christmas. 



^ The Royal Geographical Society has published an account of the earlier observations before and after 

 Humboldt's time, and this forms an historical introduction to the present report. 



