WHIRLWIND 205 



which always traverses the same spot and is 

 roused to fury by the mere giddy whirling, is a 

 whirlwind. If it is a very fierce one, and revolves 

 longer than ordinary, it ignites and causes what 

 the Greeks call a fire-wind (TT/O^O-TT^), which is 

 just a fiery whirlwind. The bursting of such 

 winds from the clouds produces almost all the 

 disasters by which herds are carried off and ships 

 lifted, bodily, right out of the water. Further, 

 some winds produce different ones by dispersing 

 the air and driving it before them in other directions 

 than that toward which they themselves have bent 

 their course. 



It occurs to me at the moment to mention 4 

 a parallel to wind that may be drawn from drops 

 of moisture. The single drops may begin to 

 incline downwards and be on the verge of giving 

 way, but yet do not manage to fall. When, how- 

 ever, several have united and the mass has imparted 

 strength, then they are said to flow and to move. 

 So, as long as there are slight movements of the 

 atmosphere disturbed at several points, they do not 

 produce wind. The latter begins only when all 

 those movements are united and concentrated in a 

 single effort. Air differs from wind in degree alone. 

 A more violent air is a wind ; air in turn is gently 

 flowing atmosphere. 



XIV 



LET me now recall a remark that I had made early 

 in this book, namely, that wind issues from cave or 

 inner recess of earth. The whole earth is not of 

 solid compact constitution down to its lowest 

 foundations, but at many points is hollow, 



