26 The Meteorological Cycle 



favor the next synthetic step." There is an intricate 

 maze of capillary spaces and air-ducts in the soil. 



Whether the soil was a cradle for emergent organ- 

 isms or not, it has been, throughout the ages, of in- 

 calculable importance in the persistent circulation 

 of matter and in what is called the meteorological 

 cycle. 



Water- vapor is drawn up from the sea and with 

 the help of dust-particles forms clouds which the wind 

 seems to shepherd across the sky. They condense on 

 the cold rocks of the mountains and the springs are 

 fed. With the help of the entrapped carbonic acid 

 the water filches mineral matter from the rocks, and 

 the streamlets form rivers which feed the sea. And 

 then the mist rises again. 



This unending cycle regulates the temperature on 

 land and sea, it mobilizes and disperses raw materials, 

 it canalizes the earth and gives approximate con- 

 stancy of composition to the waters of the ocean. 

 "Perhaps," as Professor Chamberlin says, "there is 

 no fact in the earth's career more remarkable than 

 the fidelity with which the very narrow ranges of 

 temperature, and the not less narrow ranges of 

 atmospheric constituents essential to the evolution 

 of life, have been maintained, while oscillations 

 within these permissible ranges have freely pre- 

 vailed. These limits and these oscillations were per- 

 haps as imperative for life's origin as for its pro- 

 longed maintenance." In the course of ages the 

 changes of climate have often supplied a spur and 



