NOME IV. TUFO. 



order to reach the crater, being covered with 

 this lava, we were consequently obliged to ad- 

 vance over it, following our guide, who picked 

 his steps, choosing those drosses to tread upon 

 which were the least friable ; but our labour was 

 vain, since, on reaching the looked-for term of 

 our journey, so great a quantity of smoke issued 

 as entirely to fill the mouth of the crater, and 

 prohibit all approach. 



" The guide, who had paid a visit to the same 

 spot some days before, informed me that he per- 

 ceived a considerable increase in the fermenta- 

 tion of the mountain ; and what he stated was 

 confirmed by a smoke, which ascended from a 

 number of the chasms of Monte Rosso, although 

 this mountain is at a distance of three miles from 

 the crater. 



" Before I quitted the lava, I placed the ther- 

 mometer on a piece of heavy dross, about the 

 middle of the current ; the mercury, in two mi- 

 nutes, rose to 224; (72^ Fahrenheit*). 



* " The difficulty of the situation did not admit of my making 

 experiments with the electrometer; but on examining this instru- 

 ment, at the distance of a mile from the crater, I found the diver- 

 gency of the balls extended to three lines and a fraction ; this I then 

 perceived to be owing to a cloud, which was passing perpendicularly 

 over my head ; when the foot of the electrometer touched the earth, 

 the electricity disappeared ; and repeating afterwards the experiment, 

 : I found the divergency did not exceed one line." 



