3S On the Efficacy of Paragreles. 



the rapidly decreasing temperature, as we ascend from the 

 earth's surface, it must happen that the clouds will frequently 

 be so elevated, that a congelation of the watery particles will 

 ensue ; but it is by no means certain that this is always the 

 fact when hail is formed during the warm season: the con- 

 trary is more probable from observation. But even suppo- 

 sing the theory to be perfect in this particular, there is a cir- 

 cumstance, for which it finds no place. " Hail is most fre- 

 quently attendant upon thunder ; and it is upon such occa- 

 sions that the hailstones are sometimes enormously large and 

 destructive. 11 * Is not then this connexion of a high degree of 

 electricity with hailstorms too general, and too uniform, to be 

 passed over, as uninteresting, in attempting to account for the 

 phenomena 1 So it appears to us. That electricity per- 

 forms a very important part in the formation of hail is estab- 

 lished from the facts, — that hailstorms are usually accompa- 

 nied by large quantities of that fluid ; — and that by discharg- 

 ing the electricity of a cloud, (by means of Paragreles) the 

 formation of hail is prevented. 



How then does the electric fluid aid in freezing the drops 

 of water? is the question for our consideration; and its an- 

 swer may be deduced from what we know to be the effects 

 of the discharge of an electric battery. De meme que l 1 

 on determine la formation de l 1 eau par l 1 etincelle elec- 

 trique, on est parvenu aussi a la decomposer. On l 1 est 

 d 1 abord servi, pour cela, de violentes decharges transmises 

 a travers ce liquide, et qui y perduisaient des explosions ac- 

 compagnees d 1 etincelles. 11 ! The explosions of an electric 

 cloud,will therefore, in passing through the surrounding water, 

 decompose a part of it ; and the quantity will be incompara- 

 bly greater than by our batteries, as the cause is inconceiva- 

 bly more powerful. We may very reasonably conclude, there- 

 fore, that considerable quantities of water will be resolved 

 into its constituent gases. But the water, in passing from 

 the fluid to the gaseous state, will absorb very large quanti- 

 ties of heat ; which is required to convert the bases of the 

 gases into the seriform state ; and this heat must be derived 

 from the adjacent fluid ; and consequently there will be a 

 great reduction of temperature, sufficient in many cases tc 

 freeze the particles of water. 



* Rees' Encyclopedia, Art. Hail. 



f Biot, Traite de Physique, Tom. 2, p. 436. 



