erysfallized Bodies contained in Lava. 4g 



has made the same mislake. and a much greater, when he 

 says, he saw pieces of wood slightly scorched in entire rocks 

 of the lava of Etna. 



I am in possession of a large piece of vitreous Liva which 

 I brought from the island of Vulcano, which may explain 

 this illusion. It has great bubbles, which are much elongated 

 by the flowing of the lava, and their surface is traced with 

 thready fissures, having the appearance of ligneous fibres^ 

 increased by the hue which the fumes have given them that 

 are exhaled constantly from the substance in fusion. Several 

 people who have seen this lava took it at first for wood. I 

 have another vitreous piece of lava from Lipari, the matter 

 of which is drawn out into threads so minute and so close 

 that no agatized fossil wood, the fibres of which are 

 very distinct, has more the appearance of wood than this 

 piece has, nor has it a vitreous lustre. 1 have another spe- 

 cimen, vitreous also, one of the surfaces of which, having 

 been the outer one, is traced with a multitude of very small 

 threads, arranged in some places in undulations, like thd 

 ligneous fibres round a knotty piece of wood. 



From these examples I was led to believe that the Spe- 

 cimen from the Island of Bourbon is entirely lava, with a 

 ligneous appearance upon one of its faces : because in every 

 such case, a vegetable, even in the state of wood, after its 

 combustion, which is inevitable, can only leave a void space 

 in the lava and traces of charcoal, but never the impression 

 of fibres, and far less the fibres themselves. 



In order to lay a foundation for his favourite opinion, M» 

 Fleuriau de Bellevue hazards several reasonings, which I 

 shall not follov/, because facts and not conjectures are want- 

 ing. One of his arguments is the foUowing : " The large 

 pieces of lava, which perform the first part in the eruptions 

 of volcanoes, dart out of the crater itself, as well as from 

 the sides of the mountain or its base. They come rapidly 

 out of the fires of the vcjlcano also, being incomparably 

 hotter than the substances which remain at rest in the crater. 

 This immense heat and this rapidity cause thum lo be 

 squirted out and to Jloto duivn like watery and cannot admit 



Vol. iia. Mo. 109. Jw//e IbOJ. D of 



