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CHAPTER II. 



INORGANIC PART OF PLANTS. 



The ash, or inorganic part of plants. Names of substances which 

 constitute this part : Potash, Soda, Lime, Magnesia, Oxide of 

 Iron, Oxide of Manganese, Silica, Chlorine, Sulphuric acid, 

 Phosphoric acid. Description of their several properties. 



SECTION I. SUBSTANCES WHICH CONSTITUTE THE INORGANIC 

 PART OF PLANTS. 



It will be remembered, that although by far the 

 larger portion of the plant disappears wjien fire is 

 applied, there is always something remaining called 

 the ash, or, as has been before explained, the inorganic 

 part. This name inorganic was given to denote a 

 striking difference between these two great classes of 

 bodies, the organic and the inorganic : the one being 

 products of life and living organs; the other only 

 taken by the organs to answer certain purposes, not 

 having been formed by them, and not like them liable 

 to quick destruction. 



This ash constitutes so small a part of all living 

 plants, that it was for a long time thought to be a 

 species of accidental impurity; but after a time, it 

 was found that certain substances were almost always 

 present in the ash of every cultivated plant. The 

 ash of the same plant, grown on different soils, was 

 found to have a composition of nearly the same nature; 

 thus showing that it did not take in indiscriminately 

 everything that might come in contact with its roots, 

 but had a certain power of selection. 



