138 



Analysis and Valuation of Manures 



[223 



order the percentages of moisture, organic matter, P 2 5 , CaO, 

 difference (alkalis, &c), and sand, stating as footnotes the per- 

 centage of N and its equivalent of ammonia, and also the equi- 

 valent of P 2 5 in Ca 3 P 2 8 . The more common method, 

 however, is to calculate out the Ca 3 P 2 8 equivalent to the CaO 

 present, and set out the analysis thus : 



A Bats' guano contains about 12 per cent, phosphate of 

 lime, with 5 per cent, of organic nitrogen and 4 per cent, of 

 nitric nitrogen. 



223. Fish Manure, or fish guano, is analysed exactly 

 like guano, with the exception that the oil is estimated. This 

 is done in the same manner as the oil in oil cakes (see para- 

 graphs 140, 141, and 142). The oil should not be above 3 per 

 cent., as it forms a protective covering and prevents the manure 

 from rotting in the ground. 



