, CONTENTS. 



Introduction ..17 



DIVISION I. 



THE ATMOSPHERE AS RELATED TO VEGETATION. 



CHAPTER I . 



Atmospheric Air as the Food of Plants. 



§ 1. Chemical Composition of the Atmosphere 21 



§ 2. Relation of Oxygen Gas to Vegetable Nutrition 22 



§3. " " Nitrogen Gas to " " 26 



§ 4. " " Atmospheric Water to Vegetable Nutrition 34 



§ 5. " " Carbonic Acid Gas " " " 38 



§6. » " Atmospheric Ammonia to " " 49 



§ 7. Ozone 63 



§ 8. Compounds of Nitrogen and Oxygen in the Atmosphere 70 



§ 9. Other Ingredients of the Atmosphere 91 



§ 10. Recapitulation of the Atmospheric Supplies of Food to Crops 94 



§ 11. Assimilation of Atmospheric Food 97 



S 12. Tabular View of the Relations of the Atmospheric Ingredients to the 

 Lifeof Plants 98 



CHAPTER II. 



The Atmosphere as Physically Related to Vegetation. 



S 1. Manner of Absorption of Gaseous Food by Plants »» 



DIVISION II. 



THE SOIL AS RELATED TO VEGETABLE PRODUCTION. 



CHAPTER I. 



Introductory 104 



7 



