232 On the Production of Flames in Volcanoes, 



spheric air, because we have never seen JlameSj either on the crater while in 

 action, nor on the surface of the running lavas."* 



'* One of the consequences of Davy's hypothesis, and perhaps the most 

 important, would be the disengagement by the craters of volcanoes of an 

 enormous quantity of hydrogen, either free, or combined with other 

 principles, if it really be the water which, by its oxygen, induces vol- 

 canic fires. It does not appear, however, that the disengagement of 

 hydrogen is very frequent in volcanoes. Although, during my abode at 

 Naples, in 1805, with my friends Messrs Alexander de Humboldt and 

 Leopold de Buch, I had an opportunity of witnessing at Vesuvius fre- 

 quent explosions, which threw out broken lava to a height of more than 

 200 yards, I never perceived any inflammation of hydrogen. "t 



" The brilliant light reflected by the clouds of aqueous vapour and 

 ashes suspended over the cone, produces this appearance, which is so 

 often described under the erroneous denomination of Jlames, in the ac- 

 counts of volcanic erruptions by inexperienced observers, who have no 

 acquaintance with science."| 



Sir Henry de la Beche, when describing the phenomena of an eruption 

 of Vesuvius, expresses himself thus : " The solid substances thrown up by 

 the volcano, appeared like a numerous discharge of red balls, while the 

 light of the burning mass in the interior of the crater, reflected some- 

 times in a very vivid manner by the column of vapours above, produced, 

 to the view of an observer, placed at a certain distance, the appearance 

 of flames, which there are strong reasons for believing to be illusory. It is at 

 least very certain, that almost all the cases of this nature which have been cited, 

 have no other cause than a refection of light, which varies in intensity with the 

 activity of the volcano."^ 



" The vapours illuminated by the incandescent substances which fill 

 the craters, or cover their walls, have often been taken for flames. But 

 this illusion has been combated by a great number of observers, who have 

 affirmed that true fames never issue from the crater of a volcano,'' \\ 



I myself, also, drawn away by so many authorities, when I commenced 

 to observe the phenomena of Vesuvius, said, " "We ought to take care 

 in such cases not to mistake the luminous radiation produced by the 

 stones and incandescent scoriae for flames, an error into which many 

 people have fallen ;"1I and, in fact, when I wrote this sentence, I had 

 never observed flames from Vesuvius. 



* Covelli, Storia dei fenomeni del Vesuvio, § xc. 



t Gay-Lussac, Reflexions sur les Volcans (Ann.de Chim. et de Phys. t. xxii.) 

 J Poulet Scrope, Considerations on Volcanoes, cap. 2, § 1. 

 § Manuel de Geologic (art. Volcans en activite). 



II Brongniart, Des Volcans et des terrains volcaniques (Art. du Diet. d'Hist. 

 Nat.). 



^ Spet. del Vesuv. fasc. 1, § xxvii. 



