174 



pet that surrounds the crater, We plunged the 

 thermometer into them, and saw it rise rapidly 

 to 68 and 75 degrees. It no doubt indicated 

 a higher temperature, but we could not observe 

 the instrument till we had drawn it up, lest we 

 should burn our hands. M. Gordier found se- 

 veral crevices, the heat of which was that of 

 boiling water. It might be thought, that these 

 vapours, which are emitted in gusts, contain 

 muriatic or sulphurous acid ; but when con- 

 densed, they have no particular taste ; and ex- 

 periments, which several naturalists * have made 

 with reagents, prove, that the chimneys of the 

 Peak exhale only pure water. This phenome- 

 non, analogous to what I observed in the crater 

 of Jorullo, deserves the more attention, as mu- 

 riatic acid abounds in the greater part of vol- 

 canoes, and as Mr. Vauquelin has discovered it 

 even in the porphyritic lavas of Sarcouy in Au- 

 vergne. 



I sketched on the spot a view -f- of the interior 

 edge of the crater, as it presented itself in the 

 descent by the eastern break. Nothing is more 

 striking than the manner, in which these strata . 

 of lavas are piled on one another, exhibiting the 

 sinuosities of the calcareous rock of the higher 

 Alps. These enormous ledges, sometimes hori- 

 zontal, at others inclined and undulating, remind 



* Voyage de La Perouse, t. iii, p. 2. 

 + Picturesque Atlas, folio, PL 54. 



