146 LIVING LIGHTS. 



phosphorescent. ' Ordinary hail-stones are the size of small 

 peas, but they occasionally occur large enough to kill human 

 beings ; and I have seen them so large in the Sierra Madre 

 Mountains that any shelter was preferable to exposure to 

 them. In 1707 a hail-storm occurred at the town of Como, 

 Switzerland, doing an incredible amount of damage, some 

 of the stones weighing nearly ten ounces. Darwin describes 

 a storm upon the South American pampas, in which the 

 stones that fell were large enough to kill powerful animals. 



Ice has often been observed to emit luminous sparks ; , and 

 probably one of the grandest spectacles ever witnessed, is 

 the luminous cap of a snow-covered mountain. The glaciers 

 of the Alps have been seen bathed in a soft phosphoric glow, 

 the icy rivers being distinctly marked by the phenomenon, 

 which is so brilliant, at times, that the appearance of a second 

 sunset is occasioned. Not only are the summits of Alpine 

 peaks and the glaciers luminous, but the valleys of Piedmont, 

 Valais, and others have been seen to emit from their cover- 

 ing of snow a soft blue light of singular beauty. So intense 

 is this light about the cap of Mount Blanc, it has been 

 photographed. Luminous vapors or mists may be mentioned 

 in this connection. Several times in the history of this 

 country, luminous mists or fogs have been recorded. Massa- 

 chusetts was visited by one some years ago, in which the 

 fog was so dense that observers, a few feet away were in- 

 visible, yet darkness was not an accompaniment; ^ the mist 

 seemed to be light-emitting itself, having a reddish, metallic 

 hue. Others described it as a fiery red or yellow, while 

 to some it appeared to be composed of faintly luminous 

 matter. 



In the year 1783 all Europe and a portion of Asia were 



