106 



the earth. By this means many earthquakes have bee 

 occasioned, and whole cities swallowed up. This \v 

 undoubtedly the caus-e of the great earthquake at For 

 Royal, and of that which swallowed up Lima. 3. A' 

 pent up in the bowels of the earth, if it be at any time 

 rareiitd and expanded, will struggle for vent with in- 

 credible force, and thereby both shake and tear the 

 earlh. 4. "But the usual cause of the most violent 

 earthquakes is sulphur, or some other inflammable mat- 

 ter, taking fire in the cavities of the earth, and bursting 

 t hrongrT \\hatever opposes. 



There are scarce any countries that are much subject 

 to earthquakes, which have not some burning mountain. 

 And whenever any earthquake happens, this is constantly 

 in flames, Indeed where it not that these vents thus dis- 

 gorge the fire, it would make far greater havoc than it 

 does; probably it would make the whole country for a 

 vast space round quite uninhabitable. Yea, so benefi- 

 cial are these, that we do not want instances of countries 

 frequently annoyed by earthquakes, which upon the 

 breaking out of a volcano, have been wholly delivered 

 from them. 



Perhups what causes most earthquakes of this kind, is 

 the pyrites, or iron-stone, which will take fire of itself. 

 The eiirtb, \\e know, abounds in cavities, which are, at 

 certain times, full of inflammable vapours. This the 

 damps in mines shew, which being fired, do every thing 

 as in an earthquake, only in a less degree. And the py- 

 rites only, of ail known minerals, yields this inflamma- 

 ble vapour. Nor is any mineral or ore whatever, sul- 

 phureous, but what is more or less mixed with the pyri- 

 tes. But probably the pyrites of the burning mountains, 

 is more sulphureous than ours. It is likewise in far 

 greater quantities in all the countries round the Mediter- 

 ranean than in England : a plain reason why earth- 

 quakes are se much more frequent, and more violent 

 there. 



An artificial earthquake may be made thus. 

 twenty pounds of sulphur to twenty of iron filings. 

 Mix and temper these with water, so as to form a mass 



