72 Notice of Active and Extinct Volcanos. 



the prodigious extent, inconceivable energy, and indefinite 

 continuance, and successive reproduction, of volcanic phe- 

 nomena. 



It is plainly impossible, that such results should take their 

 origin from a few comparatively puny beds of common com- 

 bustibles, and we must obviously seek for other causes more 

 extensive and more powerful ; and which are not limited in 

 their range, their energy, or their capability of reproduction. 



5. Gay Lussac* urged, with much force, against the theory 

 of burning combustibles being the cause of volcanic action, 

 that the atmosphere cannot possibly penetrate to those seats 

 of volcanic power, when there is brought into action a pres- 

 sure capable of raising a column of melted lava, three times 

 as heavy as water, to the elevation of one mile or several 

 miles. The objection seems unanswerable, as far as the at- 

 mosphere is concerned : although we may suppose, that the 

 combustion is sustained by water, provided there are com- 

 bustibles capable of decomposing that fluid, which would not 

 be the fact, with either of the combustibles named, except 

 coal, and that only at the temperature of intense ignition, 

 which must not only be produced, but must also be sustained 

 in some other way, as the affusion of water upon ignited coal, 

 unless there is also a copious supply of air, soon puts an end 

 to the combustion. 



Earthquakes, fyc. 



Professor Daubeny, in settling " what appearances are to 

 be considered as establishing the existence of volcanic 

 action," states, that " some are unwilling to admit earth- 

 quakes, as any probable indication of subterranean fire, 

 whilst others not only include them, but go so far as to 

 class hot springs, gaseous exhalations, and the eruptions of 

 mud and petroleum amongst volcanic phenomena." 



Our author reasons with candor and moderation, as to the 

 question, whether earthquakes and volcanos depend upon 

 the same cause. On this point, however, we humbly con- 

 ceive, that there can scarcely be any ground for hesitation. 



Volcanic eruptions are invariably preceded, and accompa- 

 nied by earthquakes, and when the volcano discharges its 

 contents, the earthquakes immediately relent, and ultimately 

 Cease. It is plain, therefore, that those causes which produce 



*Annales de Chimie and de Physique, v. xxii. p. 415. 



