HAIL. 151 



receive successive coatings of snow and ice as they 

 passed successively through the snow- and rain- 

 clouds, and would finally fall as characteristically- 

 shaped hailstones. 



The theory now generally received in regard to 

 the formation of hailstones is, that in such storms 

 the wind rotates around a vertical rather than 

 around a horizontal axis. If such a whirling mo- 

 tion exists between a neighboring rain- and snow- 

 cloud, the particles of snow would be successively 

 dipped into the rain- and snow-clouds, and would 

 thus receive alternate layers of ice and snow. 



A somewhat similar theory regards a hail-storm 

 as belonging to the type of the ordinary tornado. 

 The whirling motion of the air is supposed to 

 produce the alternate coatings of ice and snow by 

 the alternate exposure of the moisture to the dif- 

 ferent temperatures found in the denser and rarer 

 portions of the space around which the wind is 

 whirling. 



Hail-storms often cause great damage. A single 

 hail-storm in France has been known to cause loss 

 to the agricultural districts amounting to the sum 

 of at least one million pounds sterling. 



Although the exact cause of hail-storms is at 

 present unknown, yet the storms never occur 



