304 Dr. Donati on the 



and vitreous amphigene, imbedded in a vitreous paste. The 

 heavy scoriaceous lava, which fell in Ottajano, and on the 

 point del Palo, from one to eight inches in diameter, consist 

 also of pyroxene and vitreous amphigene. The great mass of 

 lava is very tenacious, slaggy, and brown ; the scoriaceous 

 part rough and uneven, with crystallized pyroxene (which is 

 usually the bisunitain variety), covered with brown fused coat 

 ing, and internally of a deep green colour. These scoriae con- 

 tain but little lime, and a large proportion of iron. The brown 

 sand, which fell on the night of the 26th, consisted of micro- 

 scopic particles of scoriae, pumice, a mixture of amphigene 

 and vitreous pyroxene, laminae of mica, and a large quantity 

 of magnetic iron in a state of the finest powder, a large pro- 

 portion of permuriate of iron, some muriate of soda, and a 

 small portion of sulphate of soda. I could not at this time 

 descend to the bottom of the crater to observe the sublima- 

 tions in the funnel, because, although extinguished, there was 

 yet danger. 



APPENDIX. 



Vesuvius, after the 28th of March, presented no visible 

 alteration till the 3d of July, except in the enlargement and 

 extinction of the vertical fissures on the north-east, which had 

 glowed so vividly. An undulatory trembling of the earth was 

 sensibly felt at Marsala in Sicily, about the 15th of June ; and 

 towards the end of the month an explosion of gas took place 

 in the isle of Ischia, which considerably damaged the sur- 

 rounding land. It was observed very distinctly at Castella- 

 mare, and along the coast as far as Plantelleria ; and the baro- 

 meters and thermometers rose and fell in a very extraordinary 

 manner. 



On the abovementioned day (July 3), at three in the after- 

 noon, one of the volcanic mouths near the centre of the crater 

 re-opened, and, dislodging all the extraneous materials that 

 lay upon and around it, threw into the air, with rumbling and 

 bellowing sounds, brilliant fire, with dense smoke of various 

 colours, and very shortly spread itself into a large basin ; the 

 fused substances which it furnished, falling again upon itself, 



