[ 7 } 
(4. in Plan. I.) I obferved, in my way to Naples, 
which was in lefs than two hours after I had left the 
mountain, that the lava had actually covered three 
miles of the very road through which we had re- 
treated. It is aftonifhing that it fhould have run fo 
faff ; as I have fince leen, that the river of lava, in 
the Atrio di Cavaiio, was 60 and 70 feet deep, and 
in fome places near two miles broad. When his 
Sicilian majefty quitted Portici, the noife was greatly 
increafed, and the confufion of the air from the ex- 
plolions was fo violent, that, in the king’s palace, 
doors and windows were forced open, and even one 
door there, which was locked, was neverthelefs burfl 
open. At Naples, the fame night, many windows 
and doors dev/ open ; in my houle, which is not on 
the fide of the town next Vefuvius, I tried the ex- 
periment of unbolting my windows, when they flew 
wide open upon every explofion of the mountain. 
Befides thefe explofions, which were very frequent, 
there was a continued fubterraneous and violent 
rumbling noife, which lafted this night about five 
hours. I have imagined that this extraordinary noife 
might be owing to the lava in the bowels of the 
mountain having met with a depofition of rain wa- 
ter, and that the conflict between the fire and the 
water may, in fome meafure, account for fo ex- 
traordinary a crackling and hiding noife. Padre 
Torre, who has wrote lb much and fo well upon the 
fubjedt of Mount Vefuvius, is alfo of my opinion ; 
and indeed it is natural to imagine, that there may 
be rain water lodged in many of the caverns of the 
mountain, as, in the great eruption of Mount Vefu- 
vius in 1663, it is well attefted, that feveral towns, 
among 
