382 WASHINGTON AND DAY VOLCANOES OP SOUTHERN ITALY 



ward strongly acid, dust-laden, and very irritating. This ash was damp 

 in many places, especially near the top and down the south and southeast 

 slopes, where it was impregnated and covered with salts. Most of these 

 saline incrustations were white, but there were also yellow and greenish 

 patches, these last being especially prominent on the southeast slope, 

 where they extended quite to the bottom of the cone and are well shown 

 in plate 17. The salts, mostlj'^ white, were also abundant down the north 

 slope and about the bocca on the northeast, as shown in plate 19. A pre- 

 liminary examination shows that these salts are mostly mixed sulphates 

 and chlorides of soda and less potash and ammonia. In places there was 

 sufficient copper present to copper a knife blade. 



Considerable steam was rising from the south and east slopes of the 

 cone, issuing from small fumaroles at possibly fifty more or less fixed 

 spots. The other slopes of the cone were quite free from these emanations. 



The inside walls of the crater from top to bottom are covered by a 

 somewhat festooned arrangement of fresh ash which reveals little struc- 

 ture to the observer. The bottom of the crater is something over 450 

 meters below the present rim, and appears to be entirely inaccessible, not 

 alo]ie because of the steepness of the walls, but because of the treacherous 

 ash deposits and the smoke, which is usually so thick that few who have 

 made the climb to the summit have been rewarded with a view of the 

 interior. We were fortunate enough to obtain a clear view of the bottom 

 of the crater, obscured only l)y a thin film of bluish smoke, on two occa- 

 sions — the smoke, by the way, being much more transparent to the eye 

 than to tlie camera, even when the lens is moderately screened against 

 blue. A photographic view down to the bottom of the crater is therefore 

 exceedingly difficult to obtain and is not altogether satisfactory when 

 obtained (plate 18). 



In appearance the bottom of the crater is nearly flat in the west half 

 aiul is usually covered with ash. The guides are accustomed to call atten- 

 tion to five openings, of wdiich only two could be clearly distinguished at 

 the time of our visit — one a round well perhaps 40 meters in diameter and 

 20 meters deep, with a flat floor of ash. This well is located near the 

 north wall, a little to the west of the middle, and has at least two openings, 

 both in its side walls. The smoke which emanated from this well at in- 

 tervals came invariably from the northeast opening, and usually emerged 

 from the top of the well into the open crater. Occasionally it appeared 

 to roll across the floor of the well and disappear into the opening in the 

 opposite wall without emerging into the crater at all — an extraordinary 

 phenomenon which is perhaps to be explained through a subterranean 

 connection between the central crater and the outside crater, to be de- 

 scribed below. No fresh lava was visible in the well or elsewhere in the 



