118 ELEMENTARY AGEICULTUKAL CHEMISTRY 



fluctuations, and differ somewhat with different manures, so 

 that the following figures are only to be taken as examples : 



Value " Per Unit." 



s. d. s. d. 



Nitrogen 10 to 12 



(= ammonia, 8s. 3cZ. to 9s. lO^d.) 

 Soluble phosphorus pentoxide . . . 4 1 to 5 5 



(= soluble phosphates, 2s. Bd. to 3-?.) 

 Insoluble pho.-phori-.s pentoxide . . . 2 6 to 2 9 



(= insoluble phosphates. Is. id. to Is, 7d.) 

 Potassium 4 to 4 7 



(= potash, 3s. id. to 3s. 9d.) 



An example of the valuation of a manure from analysis may 

 be useful. Suppose it is desired to calculate the value per ton 

 of a mixed manure having the following proportions of fer- 

 tilising ingredients : 



rer cent. 



Ammonia 5 



Soluble phosphates 15 



Insoluble phosphates 7 



Potash 3 



Assuming that the unit value for ammonia 4s 9s., for soluble 

 phosphates 25. Qd., for insoluble phosphates Is. (Jd., for 

 potash 3s. Gd.f the value per ton would be calculated thus : 



Ammonia 



Soluble phosphates . 

 Insoluble phospliatcs 

 Potash . 



iL6 3 6 



