GUANO. 169 



over numerous localities in the intertropical regions. It abounds 

 on many of the rocky islets of the Eed Sea, where the life-teeming 

 waters afford sustenance to innumerable sea-gulls, cormorants, 

 and pelicans ; but its most widely celebrated stores cover the small 

 Chincha Islands, not far from Pisco, about a hundred miles to the 

 south of Callao, where they form enormous layers 50 or 60 feet deep. 



The upper strata are of a greyish-brown colour, which lower 

 down becomes darker ; and in the inferior strata the colour is a 

 rusty red, as if tinged by oxide of iron. The guano becomes 

 progressively more and more compact from the surface down- 

 wards, a circumstance naturally accounted for by the gradual 

 deposit of the strata and the increasing superincumbent weight. 

 As is universally known, guano is formed of the excrements of 

 different kinds of marine birds ; but the species which Tschudi, 

 the celebrated Peruvian traveller, more particularly enumerates 

 are — Larus Tnodestus (Tschudi), Rhynchops nigra (Linn.), 

 Plotus ankmga (Linn.), Pelecanus thayus (Mol.), Phalacro- 

 corax Gaimardii and albigula (Tsch.), and chiefly the Sula 

 variegata (Tsch.). 



The immense flocks of these birds, as they fly along the coast, 

 appear like aerial islands ; and when their vast numbers, their 

 extraordinary voracity, and the facility with which they procure 

 their food are considered, we cannot be surprised at the magni- 

 tude of the beds of guano which have resulted from the uninter- 

 rupted accumulations of countless ages. During the first year 

 of the deposit the strata are white, and the guano is then called 

 'Guano bianco. In the opinion of the Peruvian cultivators, this 

 is the most efficacious kind. As soon as the dealers in guano 

 begin to work one of the beds, the island on which it is formed 

 is abandoned by the birds. It has also been remarked that, since 

 the increase of trade and navigation, they have withdrawn from 

 the islands in the neighbourhood of the ports. Under the em- 

 -pire of the Incas, the guano was regardedas an important branch 

 of state economy. It was forbidden, on pain of death, to kill 

 the young birds. Each island had its own inspector, and was 

 •assigned to a certain province. The whole distance between 

 Arica and Chaucay, a lengta of two hundred nautical miles, was 

 exclusively manured with guano. These wise provisions have 

 been entirely forgotten by the Spaniards, but the Peruvians now 

 ■ begin to discover the error of their former masters, and look 



