380 CALORIFICATION. 



itself a passage through various fissures which 

 it makes, but converts a vast quantity of water 

 into vapor and steam ; by whose united aid, 

 the resistance of the incumbent mass of earth 

 is overcome, and a general overthrow produced, 

 attended with all the consequences which have 

 been detailed. 



Some there are, who question the efficiency 

 in the means to produce the end ; and Di\ 

 Stukely, in particular, supposes that the earth- 

 quake in Asia Minor, which extended over a 

 circle of 300 miles in diameter, could not have 

 been produced by the explosion of the greatest 

 quantity of gunpowder that can be conceived ; 

 and he starts this objection for the purpose of 

 strengthening his favourite doctrine, of an elec-r 

 trie shock. According to my view of the sub- 

 ject, both suppositions are perfectly compati- 

 ble ; as the electric fire is a species belonging 

 to the same genus as fire in general, it is produc- 

 ed by the same means, and produces the same 

 effect. 



We have a multitude of facts to show that 

 the .solar rays, concentrated by means of a lens, 

 in an exhausted receiver, produce fire the most 

 intense, as well as on the summit of the most 

 lofty mountains : and it may be mentioned as 

 one, amongst other circumstances, which dis- 

 tinguishes light from fire, that while we possess 

 the most ready means of concentrating to a 



