MANURE. 159 



decomposable, their nitrogen would have given equal 

 results. 



To observe, then, the difference between salts of ammo- 

 nia unequally decomposable, let the amounts of hay produced 

 by 100 parts of nitrogen from each salt be compared. Un- 

 influenced by the considerations which have been offered, 

 these should be alike. 



The sal-ammoniac gave, for every 

 100 parts of nitrogen, 24,395 parts of hay. 



The sulphate gave, for every 100 

 parts of nitrogen, 21,660 parts of hay. 



2,735 



Now, this difference is attributable to the greater stability 

 of sulphate of ammonia. It gives up its alkali slower. The 

 plant does not so readily dissociate the elements of the salt. 



If, on the other hand, the bone-liquor is examined, it is 

 found that, because it was readily decomposed, 100 parts of 

 its nitrogen produced 24,355 parts of hay, coinciding almost 

 exactly with the product from sal-ammoniac, and confirming 

 thus the principle that nitrogen measures the value of a 

 manure. 



When all circumstances are equal, 100 nitrogen always 

 produce like effects, no matter what may be its origin. 

 Among the most important circumstances which influence 

 manure, are drought and wet. The season has its influence, 

 and years differing by temperature, moisture, and dryness, 

 show different results from the same manure. 



But it is not as muriate or sulphate that the ammonia of 

 manure is ordinarily found. 



Putrefaction gives rise to carbonate of ammonia. It has 

 been proved that the degree of saturation has no effect on 

 the result. It is of no practical importance whether the 



