22 CONTENTS. 



Use of the aerial State 159 



Liquidity 162 



Natural Chymistry - - - 163 



Mobility of Air -.-...*. 1(55 



Air the Vehicle of Sensation 166 



Fineness of Air - 168 



Fringes . ic9 



Sensibility of Air * - 169 



Effects of Heat on Air The Weather - - - - 170 



Ascent of Smoke 172 



Signs of Rain 173 



Winds .......... 174 



The Spring - 175 



Progress of the Year 178 



Rivers 180 



Value of Water 182 



Evaporation 182 



Cold Hoar-frost 185 



Catching Cold 18G 



London Fog 188 



few 192 



Morning Dew 194 



Breathing Combustion 195 



Vapour in the Air 199 



Descent of Vapour 202 



Meteors and meteoric Stones ...... 208 



Mountain Air and Mountain Mists ..... 209 



Clouds Currents in the Air - - . . - -211 



Whirlwinds 213 



Thunder-storms 214 



March of the Thunder-cloud 216 



Boiling Springs - - 219 



SECTION VII. 



WATER AND EARTH. 



General Effects of Air and Water upon the Earth - - 220 



Softer Strata of the Earth 222 



Rocks and their Productions 223 



The " Scotch Laird" and the Pebbles - - - -225 



Where to study Rocks 227 



Action of Water on the Earth 223 



Pressure of Water - -- - - - - - 229 



Characters of Mountains ....... 232 



Valleys and Basins ........ 233 



Formation of Rocks -- - - - . . . 234 



Action of Rivers ........ 236 



