NORTH-CAROLINA GEOLOGICAL SURVEY. 77 



Sulphuric acid, 1.461) 



Chlorine, 0.561 



Soluble silica, , 10.020 



Silica, 3.800 



Percentage of ash, 3.137 



The pea in composition is closely related to the cereals,and 

 in nutritive powers ranks high. Indeed the leguminous plants 

 as a class stand at the head of a certain class of nutrients. 

 The bean employed for food gives more muscle or strength 

 of muscle and endurance than the cereals. This is due in 

 part no doubt to its phosphoric acid and nitrogenous matters. 



It appears from the foregoing that the greater the amount 

 of nutrient power the more valuable they are as fertilizers. 

 Weeds which bear only small seeds, or which are composed 

 of lime, are less useful than leguminous plants, and others 

 which are closely related to the cereals. 



51. The composition of another plant which" may be in- 

 teresting in another point of view is tobacco. I design to 

 show by the analysis how much the tobacco exhausts the soil, 

 and of what elements. 



Thus, one hundred parts of the ash consist of 



Potash, 4.260 



Soda, 6.140 



Lime, 48.000 



Magnesia, 9.180 



Phosphates of lime and magnesia, etc., 14300 



Sulphuric acid, 8.420 



Chlorine 1.100 



Silica and sand, 4.800 



Soluble silica, 3.800 



100.000 



This tobacco grew in Rockingham county,, and was regard- 

 ed by the manufacturer as fine as any which is grown in the 

 northern counties, The result, however, of this analysis sur- 

 prised me, as it contained so much less of potash than can be 

 expected in the best of tobacco. It is found' by many analy- 



