On the Production of Flames in Volcanoes, 231 



it is properly purified, makes little or no difference in the illu- 

 minating power. Of course, in making this remark, it must 

 be understood that it does not at all bear on the loss that may 

 be sustained, by the diminution in the quantity of gas, by 

 leakage in the pipes, and otherwise ; a point which it is diffi- 

 cult to decide, where a company disposes of its gas, partly by 

 meter, and partly by contract according to the time, but which 

 does not affect the consumer, who has to pay for the gas that 

 passes through his meter, or by the time his burners are in use. 



On the Production of Flames in Volcanoes^ and the conse- 

 quences that may be drawn therefrom. By M. Leopold 



PiLLA. 



The question, whether volcanic phenomena are accompanied with 

 flames, is, in my opinion, of so much importance in the science of the 

 earth, that the attention of natural philosophers cannot be too strongly 

 drawn to it ; doubts are still left in the mind respecting it, which ought 

 to be removed. The greater number of men of science who have de- 

 voted themselves to the study of volcanoes, deny that there is any mani- 

 festation of this phenomenon in volcanic eruptions ; and they in general 

 think, that what the vulgar, and even many writers, have called /awi«5, 

 is nothing else than the reflection of the light produced by the burning 

 substances on the walls of the craters, and on the column of smoke which 

 issues from them. I may be permitted to quote, in reference to this, the 

 following passages from most respectable authors. 



" An unanswerable proof of the insufliciency of this hypothesis (the 

 disengagement of hydrogen gas in the eruptions of Stromboli) is the fol- 

 lowing. When the bubbles of the boiling lava burst by the escape of 

 the enclosed gas, who does not see that if this gas consisted of hydro- 

 gen, it ought, at that moment, to become inflamed on the surface of the 

 lava ? Now, it is very certain that in no eruption do we ever see the 

 slightest flame on the lava."* 



" The different metallic combustibles and metalloids may decompose 

 water, in proportion to the degree of aflSnity they possess with the 

 oxygen of the latter, and give rise to the series of acids and oxides 

 which appear in volcanoes. We ought, however, to observe, that the 

 hydrogen, on leaving its state of combination, never reaches the aper- 

 tures which vomit fire, and which are in communication with the atmo- 



• Spallanzani, Viaggi alle Due-Sicilie, t. iii. cap. 21. 



