43 Observations vpori the 



llzcci form, if it is not that, because, all the substances 

 havinjT been melted, there can be nothing except glass ia 

 their whole mass ? 



I niav even add, that it is much more extraordinary that 

 ve should, from the operations of our trifling workshops, 

 infer ihe degree of power of the fires of volcanoes, and 

 t'.ms ascribe to them an unlimited extent; and more extra- 

 ordinary still, hence to conclude the origin and formation 

 of the primordial rocks and mountains. Let ns restrict 

 ourselves to the effects produced by our own resources ; 

 and not throw ourselves into a labyrinth of illusions, by 

 concluding from small effects to great ones ; for, our means 

 being only artificial, they are not those which nature em- 

 ploys. 



'* The naturalists," M. Fleuriau de Bellcvuc proceeds, 

 *' who think that the crystals contained in lava remained 

 untouched in the midst of their fluid paste, pass over in si- 

 lence the observation of those who, as Spallanzani and Hu- 

 bert relate, have seen the lava gush out at different times as 

 water giishes out of a fountain, and form a multitude of very 

 bri'>k rivulets ; and lastly possess a degree of fluidity suffi- 

 cient for introducing itself into the smallest interstices of 

 the bodies it penetrates :" and he adds in a note, " M. Faujas 

 has in his collection a piece of a palm tree from the island 

 of Bourbon, which proves that the fluidity of the lava has 

 been very great, since it was introduced even into the fibres 

 of wood." 



An impossibility would result from this fact, if it were 

 true, i. e. that there might be lavas in fusion without incan- 

 descence ; for a body which is so combustible as a piece of 

 palm tree, or any other vegetable, would have been burnt 

 and consumed, or reduced into charcoal, on the first contact 

 of the lava. Here there is a mistake, therefore. Either the 

 matter which surrounds the piece of palm tree is not lava, 

 or the matter surrounded is not a venetable. I have read in 

 the account of a voyage lo Iceland, translated and pub- 

 lished at Paris in 1S02, that the Danish travellers thought 

 tbey saw wood in a piece of the lava of Hecla. Count de Borch 



has 

 1 



