VI 11 CONTENTS. 



The organic substances of plants. 



Structure and functions of the roots, p. 39 



Of the stem and bark, 40 



Of the leaves, 41 



Properties and composition of water, 42 



Woody fibre, 44 



Starch, 44 



Sugar and gum, 45 



Dextrine, 40 



Gluten, legumin, casein, albumen. 47 



Sources of the supply of carbon to plants, 48 



Of hydrogen and oxygen, 50 



Of nitrogen, 51 



The soil. 



Composition, general, 5$ 



Of its organic part, 53 



Necessity of this part, and how it is to be kept up, 54 



Derivation and classification of soils, 56 



Number and names of inorganic substances in, 59 



Reason for fertility or barrenness in, 61 



Mechanical improvement of, 65 



Evil effects of too much moisture in, 66 



Draining, 68 



Proper depth, 69 



Materials to be used : stones, 70 



Tiles,... 71 



Subsoil and trench ploughing-, 73 



Relations between the soil and plant, 74 



Composition of ash from crops, 7i> 



Classification of plants according to the composition of their 



ash, 79 



Effect of these classes upon the soil, 81 



Of special manures, 81 



Of plaster of paris, or gypsum, 83 



Of rotations in cropping, 85 



Manures. 



Necessity for, 89 



Irrigation, 



Vegetable manures ; green crops, 



Straw, 



Seaweed , rape dust, 



Animal manures; blood, llesh, Iniir, wool, 



Bones 



Dissolved in sulphuric acid. . .'. 



