G. Poulett Scrope — The Mechanism of Stromboli. 541 



indeed, himself noticed strings of lava which looked like dykes, in 

 the face of the great rent, but is unwilling to admit that tliey are 

 such, considering them merely long flakes or ropy portions of lava 

 that had fallen from above. The fact I have to mention in support 

 of the contrary view is the remarkable one mentioned by Spal- 

 lanzani, Hoffmann, myself, and others, that besides the opening at the 

 bottom of the crater which is filled to the brim with boiling lava, and 

 whence the explosive discharges of scoriae, etc., take place, there is, 

 or was at the several times of our visits, at least one other orifice, 

 empty to all appearance, but from which steam, seemingly dry, is 

 constantly rushing up with a dull roar and frequent stifled detona- 

 tions. This steam must proceed from lava at a lower level than 

 that of the proximate vent only a few yards off, with which it is 

 evidently not in communication for some distance down. It is 

 therefore easy to believe that other openings may give issue to lava 

 at a still higher level on the outer flank of the Schiarazza, without 

 the crater being necessarily filled at the same time. Similar facts 

 have been often recorded. For example, M. Deville saw on the 

 summit of Vesuvius, in 1856, two contiguous small craters, within 

 one of which a pool of incandescent lava continually bubbled up, 

 while the bottom of the other, at a lower level by at least 300 feet, 

 was empty; showing, as he justly observes, the extreme localization 

 of the ascending lava in separate, though closely adjoining, fissures 

 or chimneys. The parallel between the two cases is complete. 

 Several of the distinguished observers already mentioned have de- 

 scribed within the crater of Stromboli a number of additional mouths, 

 sometimes amounting to seven, and discharging either steam, stones, 

 or lava streams, and acting singly or in concert. In short, it appears 

 probable that the bottom of the crater of Stromboli, like that of 

 many other volcanos, is a mere crust of scoriform lava liable to 

 variations both in its level and in the number and character of its 

 openings. 



Enough has been said to show that there is no ground whatever 

 for attributing to Stromboli any mechanism different from that of 

 ordinary volcanos. Its activity is sluggish, and has continued for 

 a very long period. But this is a phase by no means unexampled. 

 The volcano of Masaya, in the State of Nicaragua, has been in a 

 similar condition of moderate eruptive activity since the year 1529 

 at least, (see Volcanos, 1862, p. 33), discharging at intervals of 

 fifteen minutes jets of red-hot lava fragments from its crater. 

 Mr. Squiers, in his recent work on Nicaragua, confirmed this fact. 

 Again, on the Pacific coast of Central America, in the province of 

 Guatemala, another volcano, Isalco, has been in a condition of 

 permanent activity since 1770, in which year a cone was first thrown 

 up on a plain, and has been growing in size ever since. Mr. 

 Squiers represents it as being 2,500 feet high at the time of his 

 visit, and its explosions as regularly recurring at intervals of twenty 

 minutes. This statement is borne out by the diary of my friend 

 Mr. Chas. Eden, written on board the U.S. Packet " Guatemala," in the 

 gulf of Eonseca, in the year 1859, which I have now before me. He 



