DOMAIN XII. VOLCANIC. 



of the sea, we know, from the ejection of 

 new islands in the seas of Greece; and in 

 the Atlantic near Iceland, and the Azores. 

 It may therefore be considered as a most 

 rational conclusion, that, as the ocean oc- 

 cupies two-thirds of this globe, numerous 

 volcanoes may exist at such depths, that 

 their effects are wholly unperceivable. 

 Dolomieu seems to have demonstrated that Depth of fuel. 

 the matter, which supplies the prodigious 

 eruptions of volcanoes, must lie at an im- 

 mense depth beneath the crust of the earth. 

 This position may be argued, 1. from the 

 surprising extent of earthquakes, felt from 

 Lisbon to Scotland, a space of 15 degrees, 

 or about 1000 British miles. 2. From the 

 prodigious quantity of matter ejected in 

 the course of ages ; from the comparatively 

 small craters of Etna, for example, whole 

 mountains, nay territories have issued ; 

 which, if drawn from a space near the 

 surface, the mountain must long since have 

 sunk into its own abysses. 3. From the 

 nature of the lava, which, in some in- 

 stances, has burst through the superincum- 



