NOME II. VESICULAR LAVA. 339 



ardent wishes. The volcanic craters, which are 

 still burning more or less, are usually surrounded 

 with hot sulphureous acid steams, which issue 

 from their sides and rise in the air. From these 

 the summit of Etna is not exempt; but the 

 largest of them rose to the west, and I was oti 

 the south-east side. Here likewise four or five 

 streams of smoke arose from a part somewhat 

 lower, and through these it was necessary to 

 pass; since on one side was a dreadful preci- 

 pice, and on the other so steep a declivity, that 

 I and my companion, from weakness and fatigue, 

 were unable to ascend it ; and it was with the 

 utmost difficulty that our two guides made their 

 way up it, notwithstanding they were so much 

 accustomed to such laborious expeditions. We 

 continued our journey, therefore, through the 

 midst of the vapours ; but, though we ran as fast 

 as the ground and our strength would permit, the 

 sulphureous steams with which they were load- 

 ed were extremely offensive and prejudicial to 

 respiration, and affected me in particular so 

 much, that for some moments I was deprived of 

 sense ; and found, by experience, how danger- 

 ous an undertaking it is to visit volcanic regions 

 infested by such vapours. 



" Having passed this place, and recovered by Crater, 

 degrees my former presence of mind, in less than 



