NOKTH-CAKOLINA GEOLOGICAL STJKVEY. 61 



the source from whence they are derived, as those which be- 

 long to the three kingdoms of nature, the mineral, vegetable 

 and animal, but such a division is really of small importance, 

 inasmuch as it will be perceived from the foregoing remarks 

 that all fertilizers may be traced back to the mineral kingdom, 

 even ammonia is strictly a mineral, although it abounds in 

 both the vegetable and animal kingdoms in certain combina- 

 tions. Proximately, they are either animal or vegetable ; but 

 in either case they are of a mineral origin. The fertilizers 

 which will come up for examination are ashes, marls, excre- 

 ments of animals and green crops. 



35. It needs no argument to prove the value of ashes as 

 fertilizers, we 'have only to inspect the foregoing tables of the 

 composition of the ashes of wheat, maize, oats and potatoes. 

 The composition of the ashes of forest trees brings us to the 

 same results, and as much dependence is placed upon the 

 decomposition of the standing trees in the cultivated fields it 

 is important that the fertilizers thus obtained may be shown. 

 We are obliged, in this case, to resort to the analyses of the 

 ash obtained directly by combustion. The results, however, 

 are the same in the natural process of decay as by combustion, 

 and the decayed bark, limbs and 'twigs furnish ultimately 

 what they would have furnished were they consumed by 

 fire. 



The white oak, for example, quercus alba, furnishes by 

 cumbustion an ash composed of the following elements. First 

 the bark of the trunk, which contains : 



Potash, 0.25 



Soda, 2.57 



Sodium, 0.08 



Chlorine, 0.12 



Sulphuric acid, 0.03 



Phosphates of lime and magnesia, 10.10 



Carbonic acid, 29.00 



Lime, 54.89 



Magnesia, 0.20 



Silica, 0.25 



Soluble silica, 0.25 



Organic matter, 1.16 



