The Phosphates of America. 21 



Very large deposits of phosphates of alumina and iron have 

 been discovered in the islands of Kedonda and Alta Vela, and 

 were at first mistaken and shipped in large quantities for phosphate 

 of lime. Upon complete analysis in London, however, their true 

 nature was discovered, and being quite unsuitable for the manu- 

 facture of superphosphate, they were denounced by leading agri- 

 cultural chemists as valueless for fertilizer purposes. The cargoes 

 were consequently refused by the consignees and thrown upon the 

 market at very low prices ; and so great was the prejudice against 

 them that a long time elapsed before they met with any purchas- 

 ers. The detailed composition of these phosphates is shown in 

 the following analysis, made by us from a fair and well-selected 

 sample : 



Moisture 12.36 



Water of combination 4.13 



* Phosphoric acid 30.22 



Lime 4.16 



Magnesia traces 



Oxide of iron 7.04 



Alumina 24.00 



Carbonic acid None 



Sulphuric acid " 



Fluorine traces 



Insoluble sandy matter 18.09 



100.00 



* Equal to 65.87 per cent, of tribasic phosphate of lime. 



It appears to have been forgotten, overlooked, or ignored, by the 

 opponents of these phosphates that the phosphoric acid in the soil 

 invariably exists in the form of phosphates of iron and alumina. 

 The so-called experts had probably not then learned what they are 

 now compelled to admit, that although some difficulty may attend 

 their decomposition in the factory or their transformation into 

 chemical fertilizers, these phosphates are extremely valuable in the 

 raw state if very finely ground as a direct manure. 



Nor is this a matter of any personal opinion or prejudice, for as 

 we and others have frequently shown, the iron and alumina in the 

 soils exercise an immediate transforming action upon the phosphate 

 of lime introduced into them in both natural arid artificial forms. 



Any one can demonstrate this transformation by adding either 

 peroxide of iron or alumina, or both, to a solution of lime phos- 

 phates in water charged with carbonic-acid gas (ordinary car- 



