CHEMICAL DEPARTMENT. 37 



NOTES REGARDING ANALYSES OF MANURES. 



The three ingredients of greatest importance in manures are phos- 

 phoric acid, nitrogen, and potash. 



1. Phosphoric Acid is present in manures as such, and also as phos- 

 phates of lime, magnesia, iron, and alumina. 



Phosphate of Lime is most important, and exists in two states, insoluble 

 and soluble. 



Insoluble — 



Insoluble phosphate of lime, called also") , . ■, ^ .„„, 

 Tricalcic phosphate, and i contams about 46% 



Tribasic phosphate of lime, ) phosphoric acid. 



Soluble — 



Soluble phosphate of lime, called also ") , . , <- ci o/ 



Monocalcic phosphate of lime, and erroneously > ^o^f ms about bl /, 

 Monobasic phosphate of lime, ( phosphoric acid. 



Some analysts prefer to state the soluble phosphate as 



Biphosphate of lime, called also ) contains about 72% 



Monobasic phosphate, ) phosphoric acid. 



The soluble phosphates are usually stated as equivalent to 

 so much tricalcic or insoluble phosphate. 



Soluble phosphate, multiplied by H | ^'^''triJdciT pho'sphajf 

 Biphosphate, „ „ Ij | ^^e&vly. 



Much confusion has arisen from the various methods of stating soluble fhos- 

 phate. To escape from this confusion, it has noio become the custom to 

 consider the term " soluble phosphate " to mean " phosjohate of lime 

 rendered soluble." In other words, soluble phosphate means 



THE INSOLUBLE PHOSPHATE FROM WHICH IT WAS DERIVED. 



Phosphate of magnesia occurs in small quantity in bones, &c., and is 



usually reckoned as tricalcic phosphate. 

 Phosphates of iron and alumina, when occurring in small quantity, 



are usually reckoned as tricalcic phosphate, but if the quantity is 



considerable it should be separately estimated. 



2. Nitrogen occurs in manures mostly in three forms — Ammonia salts, 



nitrates, and albuminoid matter. 



Ammonia sulphate (pure), contains 25f % ammonia. 



Ammonium chloride (pure), „ 31|% „ 



Nitrate of soda (pure), contains nitrogen equal to 20°/o ammonia. 



Albuminoid matter contains about 16% nitrogen, equal to about 19% 



ammonia, most of which sooner or later becomes available as plant 



food. 



3. Potash is found in small amount in most manures, and should be 



reckoned as anhydrous potash (K2O). 

 Sulphate of potash (pure), contains potassium = 54% anhydrous potash. 

 Muriate of potash (pure), contains potassium = fully 63% anhydrous 

 potash. 



