CONTENTS. 



Page 



The sun 134 



Proper motions of stars 135 



Double and multiple stars 136 



Distances, masses, and apparent diameters of stars . . .137 



Variable aspect of the heavens 138 



Nebulous milky-way ^ ' -f* r 't f\i ?f 4\'^\ * * -^ 



Successive propagation of light /'* . . 143 



TERRESTRIAL PHENOMENA. 



General view 4 . . 145 



Figure of the earth 154 



Density of the earth . . j i<J'-'V r '. .159 



Internal heat of the earth 161 



Mean temperature of the earth . ... .164 



Terrestrial magnetism /' V x '-/>! , . . . 167 

 Polar light, or aurora . . . . , . . ] 79 



Reaction of the interior of the earth on its exterior . . .189 

 Earthquakes . . > , ; fj ;,, r ,;; .,,,,., -;j *<,,.', . . 191 

 Eruptions of gas . ...'., + I..A 205 



Hot and cold springs 207 



Mud volcanoes . , . . . , . . 211 

 Volcanoes . < 213 



Geological description of the earth's crust .. . . . .235 



Fundamental classification of rocks ..... 236 



Endogenous or erupted rocks .' . .. . 238 



Exogenous or sedimentary rocks 241 



Metamorphic rocks . .- .' . . . , 244 



Artificial production of simple minerals . . . .256 

 Conglomerates ...*... . . 257 

 General chemical constituents of rocks . . . .258 



Palaeontology Fossil organic remains 260 



Palseozoology Fossil animals 261 



Palseophytology Fossil plants * 268 



Palseogeography State of the surface of the globe at 

 different geological epochs 274 



