Mechanism of Stromboli. 503 



its diameter about 510 feet. This statement .can only be received as 

 approximate, as at that date the brim of the crater cannot have been 

 extremely different from what it was in 1864 ; and the bounding walls, 

 which are of material the greater part of which is as ancient as is the 

 island itself, can scarcely admit of its ever having been circular, or much 

 different from the irregular gulf it presented when I saw it. From our 

 position of observation, every thing around us was of the sable colouring 

 of black lava and volcanic sand. We could not see with any distinctness 

 the fundus or bottom of the crater, a cloud of vapour issuing from its 

 bottom, and in places from its sides, nearly filling the cavity, and obscur- 

 ing the bottom even between the outbursts. This vapour smelled strongly 

 of hydrosulphuric-acid gas. At all the lower part, as well as I could 

 discern, the steep and solid walls of the crater merged into a very steep 

 funnel-shaped talus of loose materials, at the centre and bottom of which 

 was the aperture of the tube or " chimney " of the volcano. This has 

 been described by Hoffman as entering the funnel by three apertures. 

 Judging from the form of the column of steam, dust, stones, &c., as seen 

 at the first moment of ejection, the aperture appeared to me to be a single 

 one, irregular in form, and with its longest dimension in the direction of 

 the greatest width of the crater itself. Looking down from our position 

 over the foreshortened slope of black debris which plunged into the sea 

 900 feet below us, the two jaws of the Schiarrazza are seen to be com- 

 posed of huge broken-off beds of lava, which dip to seaward at various 

 depths below the surface ; these, partly by superficial decomposition, 

 partly by being covered with serpulse and corallines, are of a nearly white 

 colour ; and as we stood with the sun at our backs, the sea above these 

 beds, at either side of the Schiarrazza, on which the sun was shining, pre- 

 sented the most glorious tints, varying with the depth of the water from 

 golden-yellow to the purest emerald-green, while between these, and look- 

 ing right down over the black slope of debris, the deeper sea was of an 

 intense indigo, passing off into blackness. Nothing in the way of natural 

 colouring and wild outline combined could exceed the weird horror and 

 intense beauty of contrast when a burst from the volcano sent forth in 

 the midst its volumes of white steam and dust, which, seen by the 

 reflected light of the sunbeams shining through it, appeared of every tint 

 of ruddy brown or blood-red. From what precedes, and by reference to 

 Diagram JS"o. 1, it will be seen that the bottom of the crater-funnel can- 

 not be more than 300, or at most 400 feet above the level of the sea where 

 the tube or tubes enter it, and that the statement made by Mr. Serope 

 (' Volcanos,' p. 332, 2nd edition), viz. " the lip of the orifice at the 

 bottom of the crater is some 2000 feet above the level of the sea," is 

 largely in excess of the truth. Were that a fact, the brim of the crater, 

 which is 300 to 400 feet above the bottom, would be situated within a height 

 of about 175 feet according to Smyth's measurement, or within about 

 300 to 400 feet according to my measurement of the highest point of the 



