That the climate is changing cannot be denied ; but this 

 change is covering thousands of years, and it is not com- 

 passed by the little span of recorded history. Though thou- 

 sands of years have elapsed since the ice-sheet began to re- 

 treat, we have to go but a few hundred miles to the Yosemite 

 National Park to see regions not yet beyond the glacial con- 

 ditions of that era. 



Non-Periodic Fluctuations Occur. 



Climates change from age to age, but the systematic 

 record of past events is limited to so short a space of time 

 that no change has been observed, and no general increase 

 or decrease in either temperature or rainfall has been recorded. 



It seems a far cry back to the golden days of '49, when 

 a rain gage was set up in the oldest California Mission at 

 San Diego; but how many hundred times fifty years have 

 elapsed since the days when the lava met the sea at Point of 

 Rocks at the IMexican boundary? One is a historic period and 

 the other is a geologic epoch. 



10 



