378 M. L. Elie de Beaumount on the Structure and 



I shall only pause an instant to present some details that possess 

 an interest which is in some measure collateral. 



On the 19th September 1834 I ascended to the summit of 

 Mount Etna with M. Leopold de Buch, Professor Link, M. 

 Achille Richard, and several other savans. It has appeared to 

 me proper that a narrative of this excursion should form part 

 of the documents to warrant and support my investigation ; but, 

 in the present analysis, I shall only extract from this account 

 the two following remarks. 



It has been ascertained that the greater number of the appear- 

 ances of flames which accompany volcanic eruptions, are only 

 the effect of the rays of light which emanate from the incandes- 

 cent lava, and which are reflected by the molecules of vesicular 

 Tapour and of dust disseminated by the eruption in the atmo- 

 sphere. In consequence of this observation, doubts have been 

 raised as to whether volcanos, in any case, produce real flames. 

 These doubts have been already removed by Sir H. Davy in re- 

 gard to Vesuvius, where he ascertained, during a small eruption, 

 the existence of a real jet of flame ; and we ourselves have ob^ 

 served on Etna incontestable volcanic flames. Having left the 

 Casa ingUse about an hour and a half before daybreak, in order 

 to ascend to the edge of ih^ crater, the feeble light of the stars 

 -enabled us to perceive, on the commencement of the acclivity of 

 the upper cone, a white space whose colour was caused by the 

 alteration of the rocks, and by saline efllorescences having a very 

 styptic taste. In the midst of this space, at several points, we 

 distinguished pale and scarcely luminous flames, which seemed 

 to issue from the earth ; they occupied the orifices of several 

 irregular openings, which were from one to two yards in width, 

 and were only the enlargements of a tortuous crevice. These 

 flames were evidently produced by a gas disengaged from the 

 crevice, and which did not find the oxygen necessary for its com- 

 bustion till it reached the external air. The combustion took 

 place alrtiost exactly at the level of the surface of the ground. 

 The flamo rarely rose to the height of a yard; it produced a 

 sound somewhat intermittent, pretty analogous to that of several 

 lighted fagots, or rather that which is heard at the bottom of a 

 blast-fufnace when the blowing apparatus is badly constructed. 

 The gslses produced by the combustion did not impede the 



