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Ob. XXV.] 



FLUID LAVA. 



G23 



scoriae, were thrown up to the height of at least 10 000 

 feet, having the appearance of a column of fire.* Some of 

 these were directed by the winds towards Ottajano, and some 

 of them, falling almost perpendicularly, still red-hot and 

 liquid, on Vesuvius, covered its whole cone, part of the 

 mountain of Somma, and the valley (the Atrio) between 



them. 



matter 



„„ that which was continually issuing fresh from the crater 

 formed with it one complete body of fire, which could not be 

 less than two miles and a half in breadth, and of the extra- 

 ordinary height above mentioned, casting a heat to the dis- 

 tance of at least six miles round it. Dr. Clarke, also, in his 

 account of the eruption of 1793, says that millions of red-hot 

 stones were shot into the air full half the height of the cone 

 itself, and then bending, fell all round in a "fine arch. On 

 another occasion he says that, as they fell, they covered 

 nearly half the cone with fire. 



The same author has also described the different appear- 

 ance of the lava at its source, and at some distance from it 

 when it had descended into the plains below. At the point 

 where it issued, in 1793, from an arched chasm in the side of 

 the mountain, the vivid torrent rushed with the velocity of a 

 flood. It was in perfect fusion, unattended with any scorice 

 on its surface, or any gross materials not in a state of com- 

 plete solution. It flowed with the translucency of honey, 

 ' in regular channels, cut finer than art can imitate, and 



flowing with all the splendour of the sun.' < _ 



Hamilton,' he continues, < had conceived that no stones thrown 

 upon a current of lava would make any impression. I was 

 soon convinced of the contrary. Light bodies, indeed, of 



Sir William 



made 



pression even at the source ; but bodies of sixty, seventy, and 

 eighty pounds were seen to form a kind of bed on the surface 

 of the lava, and float away with it. A stone of 300 cwt., that 

 had been thrown out by the crater, lay near the source of 

 the current of lava : I raised it upon one end, and then let it 

 taxi upon the liquid lava ; when it gradually sunk beneath the 

 surface, and disappeared. If I wished to describe the manner 



* Campi Phlegrai. 



