[ r 4 ] 
explofion are without exception according to this de- 
scription ; but to return to my narrative. 
After having feafled our eyes with the glorious 
profpect above-mentioned (for which, as Spartian 
tells us, the emperor Adrian was at the trouble of 
afcending Etna), we looked into the great crater, 
which, as near as we could judge, is about two miles 
and a half in circumference ; we did not think it fafe 
to go round and meafure it, as Some parts feemed to 
be very tender ground. The infide of the crater, 
which is incruiled with Salts and Sulphurs like that 
of Vefuvius, is in the form of an inverted hollow 
cone, and its depth nearly anfwers to the height of 
the little mountain that crowns the 2:reat volcano. 
The fmoak, iffuing abundantly from the fides and 
bottom, prevented our Seeing quite down ; but the 
wind clearing away the Smoak from time to time, I 
Saw this inverted cone contracted almoft to a point ; 
and, from repeated observations, I dare fay, that in 
all volcanos, the depth of the craters will be found 
to correfpond nearly to the height of the conical 
mountains of cinders which ulually crown them : 
in Short, I look upon the cratersas a fort of fufpended 
funnels, under which are vail caverns and abyfles. 
The formation of Such conical mountains with their 
craters are eafily accounted for, by the fall of the 
flones, cinders, and allies, emitted at the time of an 
eruption. 
The Smoak of Etna, though very Sulphureous, did 
not appear to me So fetid and difagreeable as that of 
Vefuvius; but -our guide told me that its quality 
varies, as I know that of Vefuvius does, according 
to 
