PHOSPHORUS 59 



(found in Australasia) have been so washed by 

 rain as to contain little or no nitrogen. 



Dry Peruvian guano contains its nitrogen in the 

 form of uric acid and urates; when these have 

 undergone partial decomposition, the guano be- 

 comes damp and contains ammonium carbonate, 

 to fix which a " dissolved " guano is made by treat- 

 ing with sulphuric acid, the ammonia being con- 

 verted into ammonium sulphate and the calcium 

 phosphate rendered soluble. An " equalized " 

 guano is a Peruvian guano in which the percentage 

 of ammonia has been brought up by suitable 

 admixtures. 



