[ " ] 
agitated j but when by any accident the humours 
are checked, and do not find a free pafiage through 
their ufual channel, the body is agitated, and tumours 
appear in other parts of that body, but foon after the 
humours return again to their former channel. In a 
fimilar manner one may conceive Vefuvius to be the 
prefent great channel, through which nature dif- * 
charges fome of the foul humours of the earth when 
thefe humours are checked by any accident or fiop- 
page in this channel for any conliderable time, earth- 
quakes will be frequent in its neighbourhood, and 
explofions may be apprehended even at fome diftance 
from it. This was the cafe in the year 1538, Vefuvius 
having been quiet for near 400 years. There was 
no eruption from its great crater from the year 1 139 
to the great eruption of 1631, and the top of the 
mountain began to lofe all figns of fire. As it is 
not foreign to my purpofe, and will ferve to (hew 
how greatly they are miftaken, who place the feat 
of the fire in the centre or towards the top of a 
volcano, I -will give you a curious defcription of 
the fiate of the crater of Vefuvius, after having 
been free from eruptions 492 years, as related 
by Eracini, who defcended into it not long before the 
eruption of 1631 : “ The crater was five miles in 
“ circumference, and about a thoufand paces deepAts 
fides were covered with brufii wood,' and at the 
“ bottom there was a plain on which cattle grazed. 
** In the woody parts, boars frequently harboured ; 
“ in the midfi; of the plain, within the crater, w''as a 
“ narrow pafiage, through which, by a winding path, 
“ you could defeend about a mile amongft rocks and 
flones, till you came to another more (pacious 
C 2 ‘‘ plain 
