74 The Theory of Explojtons. 



always exifts ill the ftate of gas, and the more this gas is 

 accumulated, the more the amount of fpecific heat muft alfo 

 be augmented. 



This being premifed, whenever the lightning (which is 

 only an accumulation of elcftric gas, difcharged from one 

 cloud to pafs to another containing a lefs quantity) happens, 

 in its courfe, to ftrike a tree, &c. the tree becomes fo fud- 

 denly overcharged with caloric, that the air and other con- 

 ftituent parts of it, which are difpofed rapidly to combine 

 with heat, undergo expanfion, and thereby fliivcr the tree, 

 in order to force a paflage, and to fet themfelves at liberty. 1 

 cannot compare this phenomenon to any thing better than 

 to the difcharge of a cannon or of a muflcet ; for every body 

 knows that the difcharge of a cannon is owing to the fudden 

 expanfion of the conflituent parts of the powder by the in- 

 trodu6lion of caloric. 



In like manner, I have every reafon to believe that the 

 violent rending of a tree, by lightning or the eleftric gas, is 

 owing to a fimilar caufe ; that is, a fudden accumulation of 

 caloric, which expands, with violence, the air, &c. lodged in 

 the interllices of that body. This opinion will be readily 

 embraced, if it be confidered that the eleftric gas melts the 

 metals. If, indeed, the metals be fuddenly melted by this 

 gas, or rather by the caloric which it contains, is it not 

 thereby demonftrated that fuch a degree of heat is fufficient 

 immediately to fet fire to all combuftible* bodies, and fo far 

 to expand the air contained in the tree as to caufe the rend- 

 ing of its parts ? 



If animals which are killed by a ftroke of lightning, or by 

 the accumulation of the electric gas, receive no apparent in- 

 jury, fuch as laceration of their parts, as in the cafe of the 

 tree, their death muft be owing to a decompofition produced 

 in their bodies. This opinion, which has never been at- 

 tended to, flial! be fully developed and difcufled in another 

 work. I proceed, therefore, to the third part of my fubjedt j 



• The experiment of MefT;;. Lavoificr and Meunier, in which they 

 caufed an eleftii" I'p^rk to pafs thiouj;h j b:!lloon wh.ch contained oxygen 

 and hydrogen, to produce combuftion in order to form water, provtsliow 

 lir^e a t^uantity of caloric is contaiaed in the clcitric gas. 



ta 



