CONTENTS xiil 



71. Color 98 



72. Refraction and Dispersion 100 



73. The Rainbow . . . 101 



74. Diffusion of Light . 102 



75. Twilight 103 



76. Transmission of Light Shadows 104 



77. Eclipses . . 104 



78. Measurement of Light 105 



79. Photography , . . .107 



80. The Atmosphere and its Composition . ... . . 109 



81. Weight of the Air , 110 



82. Atmospheric Pressure and the Barometer .... 112 



83. Boiling from Another Point of View 114 



84. "Suction" . .,' . ,. ^.' . . . . .115 



85. Pumps . . . . . ; .. '.; .... .--:":, .116 



86. The Siphon . . . , . \ . " V . . . . .117 



87. Nitrogen and its Uses . . ', * . . . . 118 



88. Effects of Painting Wood Preservation . . . .120 



89. Carbon Dioxide . . . ...... 122 



90. The Chemical Engine . . .;>, ., . . ... . 124 



91. Other Constituents of the Atmosphere . :'.... ' . . 125 



92. Atmospheric Electricity . . ... .' . .126 



93. Warming the Air 127 



94. Winds . . . . . . . . . . .128 



95. Kinds of Winds 129 



96. Velocity of Winds . 130 



97. Resolution of Forces . . . . . 131 



98. The Theory of the Kite . . . . . . . 133 



99. The Theory of the Aeroplane 135 



100. Sailing a Boat 137 



101. Humidity .138 



102. Dew ". 139 



103. Frost 141 



104. Fog and Clouds 142 



105. Snow and Hail 143 



106. Rainfall Cyclones . 144 



107. Weather Observations . 146 



108. Weather and Climate 148 



109. Weather Instruments . 149 



