150 «/. W. Judd — On Volcanos. 



tions, and a full glare of fire, illuminating the storm at intervals, 

 and presenting an awful and magnificent spectacle. At times, how- 

 ever, when the wind shifted a point or two, our admiration was 

 checked, and we were obliged to run below, to avoid a thick cloud 

 of minute sand and ashes, that instantly covered the vessel and filled 

 her with a suffocating heat." 



A little later Stromboli was visited by two English geologists, each 

 of whom had paid particular attention to the character of volcanic ac- 

 tion, and who were therefore well qualified to describe what they saw. 



In May, 1819, Mr. Poulett Scrope ascended the mountain, and thus 

 describes what he witnessed : " Two rude openings show themselves 

 among the black chaotic rocks of scoriform lava which form the 

 floor of the crater. One of these is to appearance empty ; but from 

 it there proceeds, at intervals of a few minutes, a rush of vapour 

 with a roaring sound, like that of a smelting furnace when the door 

 is opened, but infinitely louder. It lasts about a minute. Within 

 the other aperture, which is perhaps 20 feet in diameter, and but a 

 few yards distant, may be distinctly perceived a body of molten 

 matter, having a vivid glow even by day, approaching to that of 

 white heat, which rises and falls at intervals of 10 to 15 minutes. 

 Each time that it reaches in its rise the lip of the orifice, it opens at 

 the centre, like a great bubble bursting, and discharges upwards an 

 explosive volume of dense vapour, with a shower of fragments of 

 incandescent lava and ragged scorias, which rise to the height of 

 several hundred feet above the lip of the crater. Many of the 

 fragments do not reach so high. Part of them fall back within its 

 circuit to be again rejected. A considerable proportion, however, 

 falling on the steep talus already described on the north side of the 

 vent, roll or slide down into the sea ; and it is evident, from the 

 crater continuing to retain its depth and form, that sooner or later, 

 after perhaps repeated ejection, all must find their way there, to be 

 distributed over the bottom of the Mediterranean." 



As bearing on the variations in the intensity of action of the 

 volcano, Mr. Scrope adds : " In the foul weather of winter I was 

 assured by the inhabitants that the eruptions are sometimes very 

 violent, and that the whole flank of the mountain immediately 

 below the crater is then occasionally rent by a fissure, which dis- 

 charges lava into the sea, but nrnst very soon be sealed up again, as 

 the lava shortly after finds its way once more to the summit and 

 boils up there as before." 



A few years later (in 1824 ? ) Dr. Daubeny visited Stromboli, but 

 did not approach sufficiently near to the crater to observe its 

 phenomena very minutely. He says : " The minor explosions were 

 in general almost continuous, but that the greater ones, which alone 

 were audible below, take place at intervals of about seven minutes : 

 the latter are sufficiently terrific." 



In 1825 Stromboli was visited by M. Biot, and in 1829 by M. 

 Virlet and the commission despatched to the Morea by the French 

 Academy. Each of these authors speaks of the explosions taking 

 place at short intervals. 



In 1831 the phenomena of this interesting volcano were studied at 



