SEASONAL WINDS ETESIANS 



are heated somewhat by the dull cloudy light that 

 can pierce to them and are less rigid during the 

 day than by night. Furthermore, all heat naturally 

 dispels cloud and drives it off from itself. There- 

 fore the sun likewise has the same effect. For that 

 reason some people suppose that the blast must 

 come from the direction in which the sun lies. But 

 this opinion is manifestly false, seeing that the 

 breeze sets in any direction, and one can sometimes 

 sail right toward the sunrise with all canvas set. 

 That could not happen if the wind were always 

 coming from the direction of the sun. 



THE Etesian winds, too, which some drag into the i 

 discussion, do not give much support to their con- 

 tention. First, I will tell you what their opinion is, 

 and, secondly, why it is not mine. The Etesians, 

 say they, do not blow in winter, because at the 

 season of the shortest days the effect of the sun 

 ceases before the cold is overcome. So, snow 

 accumulates then and freezes hard. In summer 

 the Etesian winds begin to blow at the time 

 when the day is lengthened out and the sun's 

 rays come down straight upon us. Probably, there- 

 fore, the snows smitten by the greater heat exhale 

 more moisture. The earth likewise breathes more 

 freely when uncovered and relieved of the snow. 

 So more particles issue from the northern portion of 2 

 the heavens, and are wafted toward our quarter, 

 which lies lower and is warmer. From this the 

 Etesians derive their impulse ; wherefore they begin 

 at the summer solstice, and do not blow strongly 



