GUANO. 129 



America, Africa, Australia, the West Indies, and islands in 

 the Pacific. The original Peruvian guano, the deposits of 

 which are now exhausted, was a very valuable and concen- 

 trated manure, containing nearly half its weight of ammonium 

 salts urate, C 6 H S (NH 4 )N 4 0, oxalate, (NH 4 ) 2 C 2 O 4 , and phos- 

 phate, (NH 4 ) 8 P0 4 , together with calcium phosphate and potash 

 compounds. 



It contained from 11 to 16% of nitrogen and from 10 to 12% 

 of phosphorus pentoxide. 



The guano now obtainable contains much less nitrogen 

 (about half or a little more), though often much more phos- 

 phates. 



Two varieties of guano are now imported : 



(1) Nitrogenous and phosphatic. These have accumulated in 



practically rainless districts and the excreta which 

 formed them have been desiccated before much fer- 

 mentation was possible. True Peruvian guano from 

 the Chincha Islands, and Ichaboe guano, a recent de- 

 posit, are examples of such guanos, the latter usually 

 containing from 7 to 11% nitrogen and 5 to 15% phos- 

 phorus pentoxide. 



(2) Phosphatic. These are the remains left after the weather- 



ing by rain, &c., of the dung of sea birds. Owing to 

 the moist state in which it has been kept the nitro- 

 genous matter has been lost, by solution or volatili- 

 sation, and only the mineral (phosphatic) portion 

 left. 



Considerable deposits of guano were discovered about four 

 years ago on islands lying off Damaraland, on the AYest 

 Coast of Africa, and are being extensively worked. 



An analysis of Damaraland guano gave the following num- 

 bers" : 



Earth, Jahresbericht iiber Agric.-Chem. 1900, 118. 



