478 



PHYSICAL GEOGRAPHY. 



A Snow Storm. 



mentions the case of a woman near Yeovil in Somersetshire, who remained thus 

 entombed for seven days, and was taken out alive, and recovered. A similar imprison 

 ment in the snow for eight days was endured by another in Cambridgeshire in the year 

 1799, who heard the bells go two Sundays for church while in the drift, was at last 

 rescued, but died through well-intended, but injudicious treatment. The fertility of the 

 soil is also largely promoted by the nitrogen which the snow takes up from the atmo 

 sphere. 



Hail is another form under which the aqueous vapours abstracted from the earth are 

 occasionally returned to it. The theory of Volta refers the formation of hail to the play 

 of electricity rapidly abstracting heat from the molecules of vapour in the atmosphere. 

 The common hypothesis is that of the congelation of globules of rain in their fall, by 

 passing through a stratum of dry and cold air. To account for the production of such 

 an intense degree of cold, very partial in its range, is the grand difficulty, for hail 

 generally falls in hot sultry weather. It has been remarked, that hail very rarely falls 

 at night, and is scarcely known at all in latitudes higher than 60. The course of a hail 

 storm is commonly very narrow in proportion to its length. In July 1788, a storm 

 memorable for the havoc it made, passed over France in two parallel lines from south-west 

 to north-east. The one line extended about 500 miles in length, and the other about 600 

 miles, each having a mean breadth of only 9 miles, an interval of 15 miles occurring 

 between them, in which the rain fell in torrents.- Halley describes, in the Philosophical 

 Transactions, a hail-storm of very scanty breadth, in the year 1697, which passed from 

 Snowdon in Wales, through Flintshire, cutting the north-west corner of Cheshire, and 



xtendmg through Lancashire in a right line from Ormskirk to Blackburn, on the 

 borders of Yorkshire. The hail-stones of this storm were of very considerable dimensions, 

 ploughing up the earth and burying themselves in the ground, killing poultry and sheep 

 and completely ruining the rising corn. Leslie estimates that hail-stones, an inch in 



uimeter, fall with a velocity of 70 feet per second, or at the rate of about 50 miles 



