Notice of Active and Extinct Volcanos. 71 



There are many reasons why this theory, however plausi- 

 ble, appears untenable. 



1. The quantity of any of the ordinary combustibles, which 

 could be supposed to be present in any one place, would be 

 totally inadequate to the effect. Reasoning, analogically, 

 from our knowledge of other parts of the world — what sup- 

 ply of coal, bitumen, or sulphur could be adequate to sustain 

 the fires of Vesuvius, or of Etna, of Hecla, of Cotopaxi, of 

 Teneriffe, of Sumboa, or of Kirauea ! The most powerful 

 beds of coal are but a few yards in thickness, and a few 

 miles in extent. A few capital operations of any principal 

 volcano would soon destroy the greatest existing bed of com- 

 bustibles, and instead of continuing from age to age, as ma- 

 ny of them do, all would soon be exhausted by the intense- 

 ness of their own energy, and the consumption of their inad- 

 equate magazines of fuel. 



2. There are many volcanic countries, (indeed most are 

 of this description) where the geological structure and asso- 

 ciations are such, as to forbid the existence of coal, the only 

 combustible, sufficiently abundant to countenance such a 

 theory. We should look in vain for many active volcanos, 

 in countries of the coal formation, or of the anthracite series. 

 Although volcanic fires, occasionally force a passage through 

 any and every species of formation, there is reason to be- 

 lieve, that they are deep seated — probably even in the primi- 

 tive rocks, and in granite itself, where,, of course, there is no 

 coal and little sulphur. 



3. When also (in the language of our author,) " we exam- 

 ine more narrowly into the analogies between the effects of 

 volcanic fires, and those which we know to result from the 

 combustion of either of these materials, we are soon brought 

 to confess the inadequacy of such an hypothesis to account 

 for the facts before us. What resemblance, for example, do 

 the porcelain-jaspers and other pseudo-volcanic rocks, as 

 they are improperly termed, which we observe in coal mines, 

 that have been for centuries in a state of inflammation, bear 

 to the lavas and the ejected masses of a genuine volcano ; 

 or where do we observe from them the same evolution of 

 aeriform fluids, and of streams of melted materials which 

 are so characteristic of the latter ?" 



4. The fermentation of pyrites and the combustion of sul- 

 phur and bitumen and coal, although they do, without doubt 

 produce certain effects, and sometimes those that are consid- 

 erable, still these causes are totally inadequate to account for 



