IV 



Contents* 



WATER. 

 XIX. RIVERS AND FLOODS, . . .152 



XX. TIDES, 161 



XXI. WHAT Is A SPONGE ? . . .167 

 XXII. WATER AND ICE, . . .177 



XXIII. STORED ENERGY IN WATER, . 182 



XXIV. WHY DOES ICE FLOAT ? . .192 

 XXV. GLACIERS, . . . . .198 



XXVI. EVIDENCES AND THEORIES OF AN 



ICE AGE, 207 



XXVII. GLACIAL AND PREGLACIAL LAKES 



AND RIVERS, . . . .217 

 XXVIII. SOME EFFECTS OF THE GLACIAL 



PERIOD, 230 



XXIX. DRAINAGE BEFORE THE ICE AGE, 239 



