22 

 THE GUANO OF PERU. 



Along the coast of Peru there are many islands varying in size from 

 projecting rocks to islands of some miles in circumference. Forages 

 sea birds and seals have made their homes in the sheltered coves and 

 nooks. The fish brought ashore for their young, the excrement of 

 the birds, the dead bodies of the birds, and even the eggs, have 

 contributed to this supply of phosphoric acid and nitrogen. Deposits 

 have sometimes been found under a considerable layer of earth or sand. 

 They may be composed of a thick stratum of pure guano, or intermixed 

 with sand and earth and shells. 



Some of the nitrogen contained in these guanos is in the form of 

 free ammonia and other easily decomposable compounds. So strong is 

 this ammonia sometimes that the fumes given off from guano stored 

 in the hold of the ship are almost unbearable. The preservation of 

 so much of the nitrogen is due to the lack of rains that would leach 

 it out. The dry sheltered spots where the guano is found have been 

 an almost perfect storehouse where decomposition could go on making 

 the fertilizing elements in a reasonably available form and yet conserv- 

 ing them. In this respect these islands differ from most of the guano 

 islands of the Middle Pacific; there, the phosphates are high but the 

 nitrogen is rather low. 



About 1845 shipments of guano began to be made to Europe and 

 other countries, and soon the Peruvian guano gained a worldwide rep- 

 utation. At the present time the exportations of guano are limited. 

 The agriculturalists in Peru are permitted to gather guano for their 

 estates by conforming to certain regulations. In this way an excellent 

 fertilizer containing a fair quantity of two of the costly elements of 

 plant food can be obtained at a very reasonable figure. Few other 

 countries are so blessed in this respect. 



The guanos of Peru may be divided into three classes: those con- 

 taining a high percentage of phosphoric acid and comparatively low 

 nitrogen; those containing a fair percentage of phosphoric acid and 

 high nitrogen; and those containing a fair amount of each. The first 

 class is exported to considerable extent; the second class is found only 

 in small quantities; the third class is the one used by many of the es- 

 tates and is of value chiefly for its nitrogen, as many of the soils are 

 already well supplied with available phosphoric acid. This class has 

 many features peculiar to chemically prepared fertilizers. 



