X CONTENTS 



Problems, experiments, and questions ; Part taken in plant and 

 animal life. Pages 37-41. 



CHAPTER VI 



Nitrogen. Occurrence ; Preparation ; Properties ; Importance ; 

 Problems, experiments, and questions ; Part taken in plant and 

 animal life. Pages 42-45. 



CHAPTER VII 



Carbon. Occurrence ; Preparation ; Properties ; Coal ; Allotro- 

 pism ; A reducing agent ; Combustion ; Spontaneous Combustion ; 

 A decolorizer and deodorizer ; Products of combustion ; Com- 

 pounds of carbon ; Importance ; Experiments and questions ; Part 

 taken in plant and animal life. Pages 46-55. 



CHAPTER VIII 



Water. Chemical composition ; Physical properties ; Water of 

 crystallization ; Natural waters ; Impurities and relation to dis- 

 eases ; Location of wells ; Mineral impurities ; Contamination of 

 drinking water : Methods of improving drinking waters ; Water 

 filters ; Experiments and questions. Pages 56-65. 



CHAPTER IX 



Air. A mechanical mixture ; Carbon dioxid ; Ammonium com- 

 pounds ; Moisture ; Ozone and hydrogen peroxid ; Argon and 

 helium ; Organic impurities and ventilation of rooms; Air, a source 

 of plant food ; Sources of contamination of air; Experiments and 

 questions; Importance of air in plant and animal life. Pages 66-71. 



CHAPTER X 



Acids, Bases, Salts and Neutralization. Classification of ele- 

 ments; Acids; Bases; Salts; Radicals; Naming of acids; Naming 

 of bases ; Naming of Salts ; Double salts ; Acid salts ; Basicity of 

 acids ; Two series of salts. Pages 72-79. 



CHAPTER XI 



Hydrochloric Acid, Chlorin and Chlorids. Occurrence ; Prepara- 

 tion ; Properties : Preparation of chlorin ; Properties ; The chlorin 



