during Pari o/" 1 83 1 . ^55 



Volta founded his ingenious but untenable theory of their 

 formation. In the centre of each was a small white opaque 

 nucleus, the size of a pea, and evidently one of the hail- 

 stones usually seen in England, to which the French give the 

 name of gresil, confining the term grele to the larger masses 

 of ice now under our observation. This nucleus of gresil 

 was enclosed in a coat about half an inch thick of ice con- 

 siderably more transparent than it, but still somewhat opaque, 

 as though of snow melted and then frozen again, and exter- 

 nally the rest of the mass was of ice perfectly transparent, and 

 as compact and hard as possible, resounding like a pebble, and 

 not breaking when thrown on the floor. The inhabitants of 

 Lausanne, aware that the cinereous and puffed up appearance 

 of the clouds charged with this tremendous aerial artillery 

 portended more than a mere thunder-storm, had adopted 

 the precaution of closing their Venetian shutters ; but such 

 windows as were deprived of this protection had almost every 

 pane broken : and much damage was done to the tiles of all 

 the houses, and to the gardens and vineyards * ; but less than 

 might have been expected, owing to the short duration of the 

 storm, which did not last longer than seven or eight minutes, 

 and to the circumstance of the hailstones not being very 

 numerous. 



Moisture. — It might be expected that, in so wet a summer, 

 the air would be saturated with moisture ; and, from compa- 

 rative observations on those natural hygrometers which every 

 where present themselves, I am persuaded that more moisture 

 existed in the air at Geneva during the month of May, than 

 at Pisa in the month of December, which was even more 

 rainy. I am ignorant how far the summers generally may 

 deserve the same character as the present one ; but that, in 

 winter, the air in Switzerland is considerably drier than in 

 England at that season seems proved by the fact, that one 

 of my friends at Berne keeps, during winter, his orange and 

 myrtle trees, laurustinuses, pomegranates, fig trees, and various 

 other plants, in a cellar lighted only by three small windows, 

 which are opened occasionally in fine weather, but are en- 

 tirely covered with straw during all the hard frost ; so that 

 the plants must be in total darkness great part of the long 

 winter, during which, from the beginning of November to the 

 end of April, they are placed in this subterranean green- 

 house. Under similar treatment, I apprehend that, in most 

 winters in England, orange trees and other evergreens would 

 have their leaves destroyed by mould ; and would be so ma- 



* The remarks well elucidate Dr. Mitchell's article (Vol. IV. p. 551.) on 

 " Hail in the South of France, and Insurance against loss by it," — J. D. 



