2 Phenomena and Causes of Hail Storms. 



1. Hail storms, when violent, are characterized by the 

 MEETING OF ALL THE ELEMENTS OF STORMS ; the clouds are Very 

 black; they are strongly agitated, and fly swiftly through the air, or 

 more frequently rush towards each other, attended by high winds 

 and terrific thunder and lightning.* 



2. Hail storms, of the foregoing character, are confined 

 CHIEFLY TO THE TEMPERATE ZONES. They rarely occur in any 

 form in the torrid zone ;-j- and when they do, it is chiefly on high 

 mountains. Hail is indeed frequent in the polar regions ; but it is 

 of the ordinary kind before mentioned, and is therefore not the 

 subject of our present inquiry. Of all places in the world, the 

 South of France is most remarkable for frequent and violent hail 

 storms. During the year 1829, an insurance company was form- 

 ed in France for the special purpose of affording protection against 

 their ravages. 



3. The most violent hail storms occur chiefly during 



THE warmer half OF THE YEAR, AND MOST FREq,UENTLY IN THE 



hottest months. 



4. The hail stones that fall during the same storm, are 



FOUND to be much SMALLER ON THE TOPS OF MOUNTAINS THAN IN 

 THE NEIGHBORING PLAINS. 



5. Though hail stones are of various forms, yet they freq,uent- 



LY EXHIBIT IN THE CENTRE A NUCLEUS WHICH IS WHITE AND PO- 

 ROUS, while the other parts consist of concentric layers of ice, either 

 transparent or of an opake white, or alternately transparent and 

 opake. 



6. A SHOWER of hail DURING THE WARMER SEASON OF THE 

 YEAR, IS often' FOLLOWED BY COOLER WEATHER ; in Spring and 



fall particularly, hail is a v/ell known precursor of cold. 



Whatever may be the remoter cause of this phenomenon, we can 

 be at no loss for the immediate cause, namely, a sudden and extra- 

 ordinary cold in the region of the clouds, luhere the hail stones he- 

 gin to form: Nor can there be any doubt, that the degree of cold by 

 which the nucleus is congealed, must be very intense, — far below 

 32°, or the freezing point of water, — since this nucleus, as there is 

 every reason to believe, rolls up to the final size of the hail stone, by 



Thil. Trans. Vols. IV, and V. 



t Rees says never; but the Ed. Encyc. Art. Phys. Geog. says, ' at an elevation 

 act less than 1500 or 2000 feet.' V. Tilloch's Map;. Vol. XLIII, p. 191. 



