NOETH-CAKOLINA GEOLOGICAL SURVEY. 63 



Chlorine, 4.24 



Sulphuric acid, 0.12 



Phosphates of lime, magnesia and iron, 32.25 



Carbonic acid, 8.95 



Lime, 30.85 



Magnesia, 0.36 



Silica, 0.21 



Soluble silica, 0.80 



Organic matter, 5.70 



100.18 



The pine tree gives an ash on combustion differing slightlj 

 from the foregoing, viz : 



BARK. 



Potash, 2.86 



Soda, 3.17 



Chloride sodium, 0.03 



Sulphuric acid, 3.48 



Carbonic acid, 24.33 



Lime, 31.48 



Magnesia, 0.01 



Phosphate of lime, magnesia and peroxide of iron, 22.12 



Organic matter, 3.58 



Silica, 13.40 



The most important addition which the bark of this species 

 of pine will add to the soil is soluble silica and lime, the alka- 

 lies are comparatively unimportant. 



36. The benefit which has been attributed to the stand- 

 ing dead trees is not probably due entirely to the ash which 

 the bark and limbs furnish. A more important effect may 

 be obtained by the moisture which is retained by the spread- 

 ing roots in the soil, each of which must absorb considerable 

 water and retain it for a long time. The practice adopted in 

 this particular is better adapted to a warm than a colder 

 climate. The shade even of the trunks of forest trees would 

 be detrimental to the maize crop in JSTew England or New 

 York, more, as I believe, than all the benefits to be expected 

 either from its decaying wood or the increased water in the 

 soil. 



