38 Proceedings of the Royal Physical Society. 



Ohservatory. — This is situated on Monte Canteroni, which 

 divided the two streams of the northern lava, and was conse- 

 quently exposed the whole time to the scorching heat and 

 mephitic vapours of the slag running red-hot past it on each 

 side, as well as to the showers of ashes and scoria on its roof, 

 which also rattled with the fall of the bombs and splinters of 

 rock. 



Professor Palmieri and his assistant were therefore entitled 

 to every meed of praise for their heroic resolution to abide by 

 their instruments, and watch the progress of one of nature's 

 grandest exhibitions. 



Vegetation. — Everything organic was of course destroyed 

 under the huge banks of the lava streams, but much more 

 serious and more extensive destruction to agriculture and 

 horticulture was effected by the dust showers. 



Most of the vineyards and market gardens round Vesuvius 

 for several miles were buried, and immolated by the acrid 

 dust, especially when the rains came and washed it down 

 afterwards into mud. 



Cone and Crater. — The Great Cone was split open all along 

 its north side from the top to the bottom, and let out of the 

 fissure the great flood of lava into the Atrio del Cavallo, and 

 was likewise cracked on the south side, to let out the south 

 stream of lava. 



The Crater was wholly altered from what it had been 

 before, and was now converted into a pit 600 feet deep, 

 divided into two halves, east and west, by a wall of rock, 

 that had fallen across during the throes of the volcano. 



A new crater was formed in the Atrio del Cavallo, and 

 poured out extra supplies of ashes and vapours between the 

 cliffs of Monte Somma, and Monte Canteroni. 



Meteorological Phenomena. — The weather, prior to and during 

 the first half of the eruption, was fine and clear, but subse- 

 quently thunderstorms and showers of rain prevailed un- 

 interruptedly for several days. 



These rains washed the country all round of the deposit of 

 ashes, cleansed the streets and houses of Naples, and the 

 roads and trees in the country, but occasioned damage in low 

 lying parts from the accumulation of debris. 



