VALVE OF BIRDS TO MAN. 83 



tudes of the Pacific, near the equator, guano once accumulated 

 in tremendous deposits. It dried quickly, and where there 

 were no rains to wash it away it was preserved with njost of its 

 fertilizing constituents intact. The guano found on islands 

 outside the dry latitudes is of less value, as its nitrogen is 

 quickly washed out or dissipated. The iuiportance of guano 

 as a fertilizer was recognized in Peru by the Indians more 

 than three centuries ago. Under the Incas the birds on the 

 Chincha Islands were carefullj'^ protected, and the deposits 

 of guano jealously guarded. It is said that .the penalty of 

 death was inflicted on any one who killed birds near these 

 rocks in the breeding season. 



Humboldt, returning from his .travels in tropical America 

 in 1804, carried some samples of guano to Europe, and first 

 called attention to the value of the deposits of this substance 

 on the Chincha Islands ; but it was nearly forty years later 

 that guano became a stimulus to intensive agriculture, and 

 furnished a source of revenue to civilized nations. The vast 

 deposits on these three islands covered the rocks in some 

 places to a depth of ninety or one hundred feet. The amount 

 still undisturbed in 1853 was estimated by the oflicial sur- 

 veyors of the Peruvian government as twelve million, three 

 hundred and seventy-six thousand, one hundred tons. Its 

 use was first attempted in England in 1840 ; at that time the 

 beds seemed inexhaustible. The guano trade soon became 

 so important as to be a source of diplomatic correspondence 

 between nations. It is said to have brought Peru and Chile 

 to the verge of war. By 1850 the price of Peruvian guano 

 had advanced in the United States to fifty dollars a ton, and 

 American enterprise began to seek guano elsewhere. 



Americans have since filed with the government claims 

 to about seventy-five guano islands in the South Pacific or 

 in the Caribbean Sea. The vast deposits on the Chinchas 

 are nearly exhausted, and fertilizers are now manufactured to 

 supply the demand. Undoubtedly, however, the discovery 

 and use of guano marked the beginning of the present enor- 

 mous trade in commercial fertilizers. The manurial value 

 of the phosphoric acid and nitrogen contained in fish has 

 now become quite generally recognized, and fleets of small 



