2 Phenomena and Causes of Hail Storms. 



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



MEETING OF ALL THE ELEMENTS OF STORMS 5 tllO clouds are VCry 



black J 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 rafcly occur in any 

 form in the torrid zone;f 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 uorld, the 

 South of France is most remarkable for frequent and violent hail 

 storms, louring the year 182'9, an insurance company was form- 

 ed in France for the special purpose of affording protection against 



their ravages. 



3. The most violent hail storms occer chiefly during 

 the warmer half of the year, and most freq^uently in the 



fiOTTEST 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 FKEquENT- 



LY exhibit in THE CENTRE A NUCLEUS WHICH IS tV'HlTE AND PO- 

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

 transparent or of an opake whlte^ 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 w^cll 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- 



the clouds, where the hail stones he- 



/ 



/ 



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

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

 everv reason to believe, rolls uo to the final size of the hail stone, bv 



J, 



* PliiL Trans. Vols. IV, and V. 



t Rees says never; but the Ed. Ttmyc. Art Phys. Geog. say^, * at k 

 not less than 1500 or 2000 f<;ct.' V. Tilloch's Miig. Vol. XLIII, p. 191. 



