IV CONTENTS. 



PART IV. 

 SOUND. 



I. Origin and Transmission of Sound . . . . 114 



II. Vocal arid Musical Sounds . . . . . . 120 



in. Reflection of Sounds ,124 



PART V. 



HEAT. 



I. Nature and Origin of Heat j 129 



II. The Sun a Source of Heat 133 



III. Other Sources of Heat besides the Sun ... 136 



IV. How Heat is Communicated 143 



V. The Phenomena of Dew 162 



VI. Reflection, Absorption, and Transmission of Heat . 171 

 VII. Effects of Heat 176 



PART VL 



VENTILATION AND WARMING, COMBUSTION, RESPIRATION, 

 AND NUTRITION. 



I. "Warming and Ventilation . . . . . . 204 



II. Combustion 220 



1IL Respiration and Nutrition ... . 233 



PART VII. 



LIGHT, AND HOW WE SEE. 



I. Nature and Laws of Light 241 



II. Structure of the Eye and the Phenomena of Vision . 262 



PART VIII. 



ELECTRICITY, GALVANISM, MAGNETISM, AND ELECTRO- 

 MAGNETISM. 



I. Electricity 275 



II. Galvanism 289 



III. Magnetism 295 



IV. Electro-Magnetism 299 



PART IX. 



FAMILIAR CHEMISTRY. 303 



