PHOSPHATIC GUANOS. 



331 



III. — Natural Caribbean Guano. 



Found. 



Represented. 



Phosphoric acid, 

 Lime, 



Sulphuric acid, 

 Moisture, 



25.5 to 26.5 



It was a pulverulent mass, like the two preceding samples, 



containing less carbonate of lime. 



IV. — Natural Serrano Island Guano. 



Phosphoric acid, 12.16 



Lime, 49.25 



Sulphuric acid, 0.58 



Organic matter, 3.00 



Moisture, 10.30 



The bone phosphate in this article amounted only to from 

 26 to 27 per cent., whilst the carbonate of lime reaches from 

 62 to 63 per cent. The natural mechanical condition of this 

 material, like that of the preceding samples, is very favorable 

 for speedy reaction. 



These four samples of mineral phosphates represent a 

 numerous class of so-called phospho-guanos, which, on 

 account of their richness in phosphoric acid and their excel- 

 lent natural mechanical condition deserve in a particular 

 degree the attention of all agriculturists. 



As the majority of these mineral guanos contain, usually, 

 more or less carbonate of lime, they are unprofitable for the 

 manufacture of superphosphates ; their competition in the 

 general market is thereby limited, and they sell consequently 

 at a comparatively low price ; from |18 to $20 per ton, by a 

 guarantee of from 24 to 25 per cent, of phosphoric acid. In 

 my previous report I have referred already to the value of 

 these phosphates for direct application in general farming. 



To incorporate daily a certain amount into the fresh barn- 

 yard manure by scattering it over the manure pile, or to 

 compost them for some months previous to their designed 



