THE EARTH. 83 



The famous Bishop Berkley gives an account 

 of one of these eruptions in a manner something 

 differing from the former.* " In the year 1717, 

 and the middle of April, with much difficulty I 

 reached the top of Mount Vesuvius, in which I 

 saw a vast aperture full of smoke, which hindered 

 me from seeing its depth and figure. I heard 

 within that horrid gulf certain extraordinary 

 sounds, which seemed to proceed from the bowels 

 of the mountain, a sort of murmuring, sighing, 

 dashing sound, and between whiles a noise like 

 that of thunder or cannon, with a clattering like 

 that of tiles falling from the tops of houses into 

 the streets. Sometimes, as the wind changed, 

 the smoke grew thinner, discovering a very ruddy 

 flame, and the circumference of the crater streak- 

 ed with red, and several shades of yellow. After 

 an hour's stay, the smoke being moved by the 

 wind, gave us short and partial prospects of the 

 great hollow : in the flat bottom of which I could 

 discern two furnaces almost contiguous ; that on 

 the left seeming about three yards over, glowing 

 with ruddy flame, and throwing up red-hot stones 

 with a hideous noise, which, as they fell back, 

 caused the clattering already taken notice of. 

 May 8. in the morning, I ascended the top of 

 Vesuvius a second time, and found a different 

 face of things. The smoke ascending upright, 

 gave a full prospect of the crater, which, as I 

 could judge, was about a mile in circumference, 

 and a hundred yar.ls deep. A conical mount 



* Phil. Trans, vol. ii. p. 209. 



