' . [ J 4i ] 
corn-fields, vineyards, and fome woodlands, upon 
which the matter lay to a great thicknefs, and they fay 
retain'd its heat for a long while. I was informed even 
by feveral, who had been on the fpot 4 months after 
the eruption, that the matter (which they call the 
lava) was yet fo hot, that they could not walk 
upon it : which fhews it muff be of a prodigious 
depth or thicknefs. This matter, it feems, is not of 
the fame quality nor fubftance all the way thro’ the 
body of it j for I obferved, when I went to the the- 
atre, as I defcended, that the fides of the paffage at 
tne entrance were a fort of mould, 8 or 10 feet thick ; 
after which appeared ftone, of a blackifh or dark- 
grey colour, to the thicknefs of about a yard or 4 feet 3 
then another layer of fandy earth, under which was 
a layer of the fame fort of ftone ; and that it conti- 
nued firatum fuper Jiratum , till I got to the bottom. 
The theatre and the houfes feem all to have been 
filled with earth, and being heavier at that inftant 
than any other part, of which the matter was com- 
pounded, fubfded firft. I know a cubic block of • 
ftone is heavier than a lump of any earth of the fame 
dimenfions. Therefore you may imagine, that the 
ftony part of the matter fhould precipitate firft ; but 
my notion is, that when this ftony matter was liqui- 
fied, and boiling with heat, it was lighter in pro- 
portion than the earthy part ; and that the inftant 
the boiling degree of heat was over, it could not ga- 
ther its parts together quick enough to form a com- 
pact heavy body, before the earthy part fubfided. I 
have examined this done, and find it has not, every-- 
where, the fame folidity. Reafons might be given 
for that, but 1 will not trouble you with them now: 
I wilh 
