360 Voyage of the Novara. 



up under the co-operation of several other scientific gentlemen, 

 the quantity of guano on the northernmost island, in Septem- 

 ber, 1853, was 4,189,477 Peruvian tons (about 3,740,866 tons 

 English); the middle island about 2,237,954 English tons, 

 and the southernmost 5,072,032 English tons ; or the entire 

 cubical mass was at that period about 11,050,852 tons Eng- 

 lish. Assuming an average price, this would imply a money 

 value of about £120,000,000. Since 1841, when the first 

 considerable sliipment was made, to 1861, there had been 

 exported from the Chincha Islands 3,000,000 tons of guano, 

 wortli about 135,000,000 dollars (£29,250,000). 



At first, owing to the enormous mass of guano left to accu- 

 mulate undisturbed for centuries, the very natural error was 

 made of reckoning the quantity deposited at too high an 

 estimate, and the amount annually taken at too low a figure.* 

 Hence it happened that a few native and many foreign 

 writers have spoken of these islands as affording a supply 

 which only centuries could exhaust. It is now, however, 

 ascertained that, supposing the export proceeds at its present 

 rate, only 25 to 30 years Avill elapse ere the entire strata of 



* Only the immense numbers of sea-fowl, their extraordinary voracity, and the 

 bounteous provision for supplying them with food, can furnish any possible explana- 

 tion of the enormous mass accumulated here, even allowing for such a lapse of time. 

 Mr. Tschudi, in the'course of his travels in Peru, once kept for several days a live Sula 

 varierjata, w^hich he was continually feeding with fish. He carefully collected the 

 excrement, wl>en, notwithstanding these birds eat much less in captivity than in a 

 state of nature, it voided in a day from 3| to 5 oz. ! According to other investiga- 

 tions in natural history, it seems that the pelican eats 20 lbs. a day offish. 



