CONTENTS. 



Introduction, 



Page. 



7 



PART L—The Baw Materials of Plant Food. 



First Chapter— Matter and its Forms, - - - 13 



Second Chapter — The Organic Elements, - - 17 



Third Chapter— Carbon, Its Nature and Action, - - 19 



Fourth Chapter — Oxygen and How it Acts, - - 24 



Fifth Chapter— Nitrogen, Its Nature and Effect, - - 26 



Sixth Chapter — Acids, Alkalies and Salts, - - 30 

 Seventh Chapter — The Mineral Plant Constituents: Lime, 



Salt, Sulphur, Soda, Magnesia and Silicon, - - 36 

 Eighth Chapter — The Mineral Plant Constituents: Phos- 

 phorus and Potassium, ... - 43 

 Ninth Chapter — Chemical Symbols, Formulas and Atomic 



Weights, 47 



PART II.— The Available Sources of Supply. 



Tenth Chapter — What Our Soils are Made of, - 55 

 Eleventh Chapter — The Soil as Cheapest Source of Plant 



Food, 61 



Twelfth Chapter — The Essential Plant Foods and their 



Trade Values, .-.--. 65 

 Thirteenth Chapter— The Worth of Domestic Manure, 70 

 Fourteenth Chapter — Value of other Domestic Manures, 78 

 Fifteenth Chapter — The Concentrated Complete Man- 

 ures, ._.---- 84 

 Sixteenth Chapter— Where can we get our Nitrogen ? - 93 



