302 TOUR THROUGH ITALY. [1804. 



light again ; I fancy this is from the humidity. I 

 had brought a large bottle of pure water, and I emptied 

 nine-tenths of it carefully at the deepest part of the 

 air, which had not been much agitated ; then corked 

 and agitated for a minute. Eapid absorption ; much 

 more than with common carbonic -acid gas. Took 

 from the grotto a full mouthful, and tasted nothing 

 but heat. 



Air of grotto not at all bad ; the heat great. 

 If you look along the stratum you see a very singular 

 appearance. At a certain height very unequal, for 

 the ground is unequal you see a level of mist, one 

 definite line between the good and bad air ; the latter 

 being like steam, and hot. It lies like water in a cup, 

 and the heat does not make any mixture. 



Baths of St Girolamo in neighbourhood on banks 

 of lake : modern building, with chimneys which 

 steam like smoke. The vapour is very hot, and is sul- 

 phurous and hydrogenous. In one part, if a light is 

 held, it smokes black, without flame. At other times, 

 was told, it flamed. Suppose this depends on propor- 

 tion of water and sulphur. In some places it is acid, 

 and forms acidulous sulphates, which abound in great 

 masses; most frequently acid and sulphurous, and 

 hydrogenous. 



Keturned to Naples. Mountain had a dull red 

 light over it ; rather fine ; and the passage of the 

 grotto was in a high degree picturesque. Torches 

 were necessary. 



Nov. 2. After breakfast, went to the Monte ; 



