CONTENTS. 



True meaning of the word AGRICULTURE, page 1 



Division of bodies into organic and inorganic substances, ... 4 



Organic elements of plants. 



Carbon, 6 



Hydrogen, 7 



Oxygen, 9 



Nitrogen, 11 



Inorganic part of plants, or ash. 



Potash, 16 



Soda, 17 



Lime, 17 



Magnesia, 17 



Iron, 18 



Manganese, 19 



Silica, 19 



Chlorine, 20 



Sulphuric acid, 21 



Phosphoric acid, 22 



Variations in the composition of ash, 23 



Sources of the organic food of plants. 



Carbonic acid gas, 28 



Quantity of, in the atmosphere, 30 



Absorbed by the leaves of plants, 31 



Furnishes carbon to the plant, 32 



Carbon also derived from organic substances in the soil, .... 33 



Sources of oxygen and hydrogen of plants, 35 



Sources of nitrogen of plants, 35 



Ammonia, 36 



Nitric acid, 37 



