J. W. Judd — On Volcanos. 105 



Liparote to accompany him into the crater. A resolute Calabrian, 

 banished for his crimes to Lipari, was at last prevailed upon, by 

 the offer of a large reward, to make the venture. Spallanzani 

 describes the bottom of the crater as being oval in form, perhaps 

 one-third of a mile in circumference, and covered With sand like 

 the sides. The walls were almost perpendicular, and so high that 

 Spallanzani judged them to exceed a quarter of a mile. It was 

 only on the south-east side of the crater, where some of the 

 materials had slipped from the sides, and formed a sloping talus, 

 that access was possible. 



In the centre of the bottom rose a small hill, about 45 feet in 

 diameter, from every part of which a dense white smoke arose, its 

 surface being encrusted with salts. On the west side of the crater- 

 floor a mouth 30 feet in circumference gave off a column of dense 

 white smoke with a loud roaring noise, and the explosions from this 

 aperture had evidently blown away part of the adjacent crater- wall. 

 Such was the heat and sulphurous stench proceeding from this "bocca" 

 that it was impossible to approach it closely ; its sides, however, could 

 be seen to be coated with stalactites composed of sulphur and 

 various salts. A spring of water, also depositing stalactites, was seen 

 issuing at a height of about eight feet from the floor of the crater. 

 All over the interior of the crater, and at many points around it, 

 innumerable fumaroles poured forth jets of vapour, and in many 

 places it was only necessary to stamp with the foot in order to pro- 

 duce fresh ones. The gas issuing from these apertures, the sides of 

 which were intensely hot, sometimes extinguished a candle brought 

 near them; but at other times the gas itself became ignited, and 

 burned for several minutes with a bluish-red flame. At night several 

 bluish flames could be seen rising from the bottom to the height of 

 half a foot or sometimes higher ; and these were most numerous and 

 conspicuous in the central eminence. 



Spallanzani describes the heat at the bottom as being so great as 

 to burn his feet, causing him to seek refuge on the large blocks of 

 lava scattered about. The odour of sulphuretted hydrogen was so 

 strong as greatly to affect his respiration ; it was in consequence very 

 difficult to walk round the crater, and quite impossible to cross it 

 near the middle. The action of the acid vapours on the fragments 

 of glassy rock was very marked ; and in one case Spallanzani was 

 able to observe the commencement of change produced in a piece of 

 black lava, which he jammed into the mouth of a fumarole and re- 

 examined after the lapse of 32 days. 



These clear descriptions of the great Italian philosopher enable us 

 to refer without doubt to the grand eruption of 1786 the pro- 

 duction of the existing vast crater of Vulcano ; and this crater, it 

 is probable, did not undergo any material changes, except in the 

 number, position, products, and violence of discharge in its fumaroles, 

 till the eruptions of 1873-4. That the signs of activity should have 

 been much more marked two years after the great eruption than they 

 afterwards became is no more than might have been expected. The 

 amount of igneous action going on in 1788 was sufficient to cause 

 an obscure red glow oyer the crater by night. 



