CONTENTS xi 



PAGE 



Heavier Than Water. Density of Solids Lighter Than 

 Water. Common Uses of Water. Hardness of Water. 

 Purification of Water. City Water Supply. 



CHAPTER VIII 



HEAT. V. Y ,' . , ., ...>' . .' . ... . 126 



Sources of Heat. Heat by Friction. Heat by Com- 

 pression. Heat from Chemical Action. The Sun. 

 Measurement of Temperature. Effects of Heat. 

 Expansion. r- Expansion of Liquids. Expansion of Gases. 

 Fusion. Vaporization. Boiling. Relation of Boil- 

 ing Point to Pressure. Laws of Ebullition. 



CHAPTER IX 



QUANTITY OF HEAT AND TRANSMISSION OF HEAT . . . 137 



The Calorie. Heat Capacity. - Latent Heat. Trans- 

 I ference of Heat. Conductivity of the Earth. Conduc- 

 tivity and Sensation. The Fireless Cooker. The Thermos 

 Bottle. The Davy Safety Lamp. Convection in Liquids. 

 Convection in Gases. Radiation. Heating and Ven- | 

 tilating of Buildings. - Hot-air Heating. Hot-water Heat- A 

 ing. The Thermostat. Ventilation. Need of Moisture ) 

 in the Air. 



CHAPTER X 



WEATHER . . ' \ . .. : Y , . . . . . 152 



Meaning of the Term " Weather." Functions of the Air. 

 Colors of the Atmosphere. Air Density. Isobars. 

 Atmospheric Temperature. The Thermograph. Iso- 

 therms. Change of Temperature with the Seasons. 

 Movements of the Atmosphere. - Terrestrial or Planetary 

 Winds. Trade Winds. Prevailing Westerlies. Cy- 

 clonic Winds. Hurricanes. Winds with Special Names. 

 Monsoons. Humidity and Precipitation. The Dew 

 Point. Dew and Frost. Clouds. Cumulus Clouds. 

 Cirrus Clouds. Stratus Clouds. Rainfall. Thunder- 

 storms. Weather Changes. The W^eather Bureau. 



