276 QUESTIONS. 



7G. What takes place when vapor is formed ? How is rain supposed 

 to be brought on ? 



CHAPTER IV. 77. What instruments measure the changes which 

 take place in the atmosphere ? 78. On what principle is the thermom 

 eter constructed ? 79. By what experiment is this proved ? But what 

 other ? 80. Describe Fahrenheit s thermometer. What is meant by 

 graduated? What is the freezing point? Goon. The boiling point ? 

 Degrees? How far need a thermometer be graduated? 81. On what 

 principle is a barometer constructed? How can it be weighed? How 

 heavy is air ? Water ? 82. The effects of the weight of the air ? The 

 purpose of a barometer ? 83 How is a barometer constructed ? 84. 

 Why does the mercury rise in the barometer ? How are changes in the 

 weather foreshown ? 85. What is the pressure of the air on a square 

 inch ? 80. How is fair weather foreshown ? How foul weather ? How 

 a violent wind? 87. A Lowell barometer ? Describe it. A vernier ? 

 88. How far may change of weather be predicted ? What has been 

 done to discover the laws of storms ? 89. Signs of rain ? 90. The 

 principle of the hygrometer? 91. How is a hygrometer made? 92. 

 A still more delicate one ? 93. The use of these three instruments ? 

 94. What do variations in the temperature of the air depend on ? 95. 

 What changes take place in the column of air above us ? 9G. What do 

 variations in the moisture depend on ? Which winds are moist winds ? 

 Which dry and cold ? On what else does the moisture depend ? How 

 does heat act ? 97. Other atmospheric phenomena ? 98. On what docs 

 the formation of dew depend ? Radiation of heat ? What kind of sur 

 face radiates most abundantly ? Why? What happens when the sun 

 sets ? What &quot;becomes of the heat ? How is dew formed ? Why is it 

 not formed in a cloudy night ? 99. How is hoar-frost formed ? 100. 

 Climate of a country? 101. New England climate? 102. Influence 

 of climate? Acclimatize? 103. Causes of diversity of climate? Gen 

 eral? Second? Third? Another? 104. Some of the local causes? 

 After a rain in summer, if the clouds disperse at night, why is it com 

 monly cool ? If it continues cloudy at night, why does the heat com 

 monly continue ? 



CHAPTER V. 105. Water? How abundant is it? How important 

 to plants ? 10G. A still more powerful solvent ? 107. Three forms of 

 water ? On what do they depend ? First form ? Describe the change 

 which takes place from the action of heat? The freezing point? 

 Latent heat? Second form? Describe the effect of heat upon it. 

 What is meant by evaporate? How much heat is required to boil 



