INORGANIC ELEMENTS OP 



CHAPTER 



THE COMPOUNDS OF THE INORGANIC ELEMENTS 

 OF PLANTS. 



The inorganic elements of plants, viz. potash; soda; 

 magnesia; lime; phosphoric acid; sulphuric acid; silica 

 and chlorine, exist in combination; and never in their 

 original elementary condition as simple substances. It has 

 been shown that the organic substance of plants contains- 

 four elementary substances ; oxygen, hydrogen, carbon, and 

 nitrogen in various proportions; and that the inorganic 

 part of them is made up of eight elements ; mentioned in a 

 previous chapter ; and rarely of a very small portion of a 

 few others chiefly, aluminium, iron and manganese. These 

 eight elements are chiefly in combination as shown in the 

 following enumeration of them. 



With the exception of sulphur these elementary bodies- 

 are not known to exist on the surface of the globe in their 

 simple uncombined state, but in combination as above men- 

 tioned they form the greater part of the mass of the earth 

 and of the soil upon its surface. It is these combinations- 

 which are of interest to the farmer in his study of the prin- 

 ciples and laws of vegetable growth. 



POTASSIUM AND ITS COMPOUNDS. 



POTASSIUM is of most importance in its form of 

 CARBONATE OF POTASH, 



