136 HOW CROPS GROW. 



• CHAPTER II. 

 THE ASH OF PLANTS. 



§ 1. 

 THE INGREDIENTS OP THE ASH. 



As has been stated, the volatile or destructible part of ■ 

 plants, i. e., the part which is converted into gases or 

 vapors under the ordinary conditions of burning, con- 

 sists chiefly of Carbon, Hydrogen, Oxygen and Nitro- 

 gen, together with small quantities of Sulphur and Phos- 

 phorus. These elements, and such of their compounds 

 as are of general occurrence in agricultural plants, viz., 

 the Organic Proximate Principles', have been already 

 described in detail. 



The non-volatile part or ash of plants also contains, 

 or may contain, Carbon, Oxygen, Sulphur, and Phos- 

 phorus. It is, however, in general, chiefly made up of 

 eight other elements, whose common compounds are 

 permanent at the ordinary heat of burning. 



In the subjoined table, the names of the 13 elements 

 of the ash of plants are given, and they are grouped 

 under two heads, the non-metals and the metals, by rea- 

 son of an important distinction in their chemical nature. 



ELEMENTS OP THE ASH OF PLANTS. 



Mon-Metals. Metals. 



Oxygen. Potassium. 



Carbon. Sodium. 



Sulphur. Calcium. 



Phosphorus. Magnesium, 



Silicon. Iron. 



Chlorine. Manganese. 



If to the above be added 



Hydrogen and Nitrogen 



