SUN AND CLIMATIC VARIATION 55 



Poles, and this would have sufficed to bring about a complete 

 alteration in the seasons, or even to have caused their dis- 

 appearance. They might equally well have altered the 

 geographical position of the Poles without increasing the 

 periodic modifications of the inclination of the earth's axis 

 to the ecliptic. It is, however, only after the inadequacy of 

 explanations based on astronomical calculations has been 

 demonstrated that these new data can be studied to advantage. 1 



1 For questions relating to climate see Febvre's Geographical Introduction 

 to History. 



